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Matrix Metalloproteinases and Diabetic Vascular Complications
Abstract
Diabetes mellitus (DM) is associated with an increased incidence of cardiovascular events and microvascular complications. These complications contribute to the morbidity and mortality associated with DM. There is increasing evidence supporting a role for matrix metalloproteinases (MMPs) and their inhibitors (tissue inhibitors of matrix metalloproteinases - TIMPs) in the atherosclerotic process. However, the relationship between MMPs/TIMPs and diabetic angiopathy is less well defined. Hyperglycemia directly or indirectly (eg, via oxidative stress or advanced glycation products) increases MMP expression and activity. These changes are associated with histologic alterations in large vessels. On the other hand, low proteolytic activity of MMPs contributes to diabetic nephropathy. Within atherosclerotic plaques an imbalance between MMPs and TIMPs may induce matrix degradation, resulting in an increased risk of plaque rupture. Furthermore, because MMPs enhance blood coagulability, MMPs and TIMPs may play a role in acute thrombotic occlusion of vessels and consequent cardiovascular events. Some drugs can inhibit MMP activity. However, the precise mechanisms involved are still not defined. Further research is required to demonstrate the causative relationship between MMPs/TIMPs and diabetic atherosclerosis. It also remains to be established if the long-term administration of MMP inhibitors can prevent acute cardiovascular events.
... ECM turnover is tightly controlled through a set of MMPs and their inhibitors, the tissue inhibitors of metalloproteinase (TIMPs). Multiple lines of evidence have shown that the MMPs/TIMPs equilibrium is disturbed in DM (Kadoglou et al., 2005). One important growth factor that governs ECM protein synthesis and degradation is TGF-β. ...
... Despite the wide variation in reported MMP activity or expression in plasma or in tissue, which might reflect the complexity of ECM environment and the duration of hyperglycaemia, these studies have proved that DM induces an important dysregulation of MMP/TIMP system resulting in pathological vascular remodelling. In general, it is thought that hyperglycaemia tips the MMPs/TIMP balance towards the breakdown of ECM components (Kadoglou et al., 2005). However, the local enzyme activity in a specific tissue might be different. ...
... Moreover, it has been observed that DM protects the aorta against aneurysm growth by modulating ECM synthesis/degradation in the vessel wall (Raffort et al., 2018). In contrast, in atherosclerotic plaques, the activity/level of MMPs has been reported to be increased in diabetic patients resulting in plaque destabilisation (Kadoglou et al., 2005). Therefore, it is plausible that the diabetic environment in the current study has resulted in ECM thickening, in particular, collagen by downregulation of MMPs in the aorta wall. ...
... In addition to this, bosentan administration rather than atorvastatin triggered VSMCs' accumulation in the plaques, the predominant cellular sources of the ECM [38]. Our findings are of clinical relevance, since the alteration in MMP/TIMP balance has been associated with atherosclerotic plaque vulnerability and adverse cardiovascular events in a clinical setting [39,40]. Hence, bosentan seems to possess the potential of reducing plaque vulnerability, even at a lower extent than atorvastatin, by shifting the balance between the production and degradation of ECM towards higher intra-plaque collagen and elastin within the atherosclerotic lesions [41]. ...
... For each parameter, we then averaged all values of all sections per mouse. For the measurement of the relative concentrations of the stained molecules by immunohistochemistry, the segmental stained plaque area was expressed as the percentage of the whole atherosclerotic plaque area [39]. We then averaged the values of all plaques per animal and then for each group. ...
Bosentan, an endothelin receptor antagonist (ERA), has potential anti-atherosclerotic properties. We investigated the complementary effects of bosentan and atorvastatin on the progression and composition of the atherosclerotic lesions in diabetic mice. Forty-eight male ApoE−/− mice were fed high-fat diet (HFD) for 14 weeks. At week 8, diabetes was induced with streptozotocin, and mice were randomized into four groups: (1) control/COG: no intervention; (2) ΒOG: bosentan 100 mg/kg/day per os; (3) ATG: atorvastatin 20 mg/kg/day per os; and (4) BO + ATG: combined administration of bosentan and atorvastatin. The intra-plaque contents of collagen, elastin, monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-a (TNF-a), matrix metalloproteinases (MMP-2, -3, -9), and TIMP-1 were determined. The percentage of lumen stenosis was significantly lower across all treated groups: BOG: 19.5 ± 2.2%, ATG: 12.8 ± 4.8%, and BO + ATG: 9.1 ± 2.7% compared to controls (24.6 ± 4.8%, p < 0.001). The administration of both atorvastatin and bosentan resulted in significantly higher collagen content and thicker fibrous cap versus COG (p < 0.01). All intervention groups showed lower relative intra-plaque concentrations of MCP-1, MMP-3, and MMP-9 and a higher TIMP-1concentration compared to COG (p < 0.001). Importantly, latter parameters presented lower levels when bosentan was combined with atorvastatin compared to COG (p < 0.05). Bosentan treatment in diabetic, atherosclerotic ApoE−/− mice delayed the atherosclerosis progression and enhanced plaques’ stability, showing modest but additive effects with atorvastatin, which are promising in atherosclerotic cardiovascular diseases.
... Based on recent data, MMP-9 displays potent proatherogenic properties by promoting fibrous-cap degradation and plaque destabilization [8,28]. The association between coronary artery disease (CAD) and elevated serum MMP-9 levels is well established, while reducing MMP-9 levels is associated with favourable long-term cardiovascular outcomes [29,30]. ...
... Growing evidence supports the protective role of TIMP-2, an inhibitor of MMP-2 and MMP-9, against cardiovascular disease [28,37]. Its pharmaceutical and non-pharmaceutical modification has recently emerged as a novel therapeutic target [38]. ...
Aim
To evaluate the effects of exercise training (ET) on cardiac extracellular matrix (ECM) proteins homeostasis and cardiac dysfunction in mice with diabetic cardiomyopathy.
Methods
Thirty-six male C57BL/6 mice were randomized into 3 groups for 8 weeks (12mice/group): Diabetic control-DC: Diabetes was induced by single streptozotocin injection (200mg/kg i.p.); Diabetic exercise-DE: Diabetic mice underwent ET program on motorized-treadmill (6-times/week, 60min/session); Non-diabetic control-NDC: Vehicle-treated, sedentary, non-diabetic mice served as controls. Before euthanasia, all groups underwent transthoracic echocardiography (TTE). Post-mortem, left-ventricle (LV) samples were histologically analysed for ECM proteins (collagen, elastin), matrix metalloproteinases (MMPs) and their tissue inhibitors (TIMPs).
Results
DC group showed significantly higher cardiac contents of collagen and MMP-9 and lower elastic concentration than NDC (p < 0.001). The implementation of ET completely outweighed those diabetes-induced changes (DE vs NDC, p > 0.05). TIMP-1 levels significantly increased across all groups (DC: 18.98 ± 3.47%, DE: 24.24 ± 2.36%, NDC: 46.36 ± 5.91%; p < 0.05), while MMP-9/TIMP-1 ratio followed a reverse pattern. ET tended to increase MMP-2 concentrations versus DC (p = 0.055), but did not achieve non-diabetic levels (p < 0.05). TIMP-2 cardiac concentrations remained unaltered throughout the study (p > 0.05). Importantly, ET ameliorated both LV end-systolic internal diameter (LVESD) (p < 0.001) and the percentage of LV fractional shortening (FS%) (p = 0.006) compared to DC. Despite that favorable effect, the cardiac function level of DE group remained worse than NDC group (%FS: p = 0.002; LVESD: p < 0.001).
Conclusion
Systemic ET may favorably change ECM proteins, MMP-9 and TIMP-1 cardiac concentrations in mice with diabetic cardiomyopathy. Those results were associated with partial improvement of echocardiography-assessed cardiac function, indicating a therapeutic effect of ET in diabetic cardiomyopathy.
... Hyperglycemia is well known to produce increases in oxidative stress, being NADPH oxidase the main source of ROS [20]. Furthermore, oxidative stress promotes the increase of MMPs activities in the early phase of diabetic nephropathy [21][22][23]. Therefore, the aim of this study was to explore whether hyperglycemic levels change the expression of claudins-2 and -5 and to examine if such changes are dependent on oxidative stress and the activity of metalloproteinases affecting the proximal tubule and glomeruli functions, respectively. ...
... Hyperglycemia and oxidative stress have been correlated with an elevation of MMP-2 and MMP-9 activity in early diabetic nephropathy [21][22][23]. Therefore, we evaluated the renal activity of these metalloproteinases, which might explain the decreased expression of claudin-2 and claudin-5 due to proteolytic degradation. ...
Aims
This study attempts to elicit whether the level of hyperglycemia in an early stage of diabetic nephropathy changes the renal expression of claudins-2 and -5 and to determine the involvement of glucose-induced oxidative stress.
Main methods
Streptozotocin-induced type-1 and type-2 diabetic (DM1, DM2)-rat models were used. At 14-week old, the rats were placed in metabolic cages to evaluate proteinuria, creatinine clearance, and electrolyte excretion. Proximal tubules and glomeruli were isolated and analyzed by Western blot and immunofluorescence. Renal oxidative stress and metalloproteinase activities were evaluated.
Key findings
We found that claudin-5 expression in glomeruli and claudin-2 expression in proximal tubules were significantly reduced in DM1 versus DM2 model, paralleling with higher proteinuria and loss of sodium and potassium reabsorption, increased malondialdehyde levels, but lower antioxidant capacity in both models. Enzymatic activity of MMP-2 and-9 was increased in both diabetic groups versus control being higher in DM1 than DM2, suggesting higher claudin's degradation.
Significance
The level of hyperglycemia determines the time-dependent progression to diabetic nephropathy; hyperglycemia-induced oxidative stress parallels an increase in metalloproteinases (MMPs) activities consequently affecting the integrity of claudin-2 and -5 in glomerulus and proximal tubule. Our results suggest that chronic high-glycemia levels in early stages of diabetic nephropathy decrease expression of claudins-2 and -5, increase oxidative stress, and induce MMP-activity faster than chronic middle-glycemia levels.
... Pancreatic β cell apoptosis is present in both type 1 and 2 DM [90]. Diabetes mellitus is believed to stimulate the production of several MMPs which contribute to macrovascular and microvascular complications such as coronary artery disease, peripheral arterial disease, stroke, nephropathy, neuropathy, and retinopathy [91]. Experimental DM in rodents is associated with β cell apoptosis that leads to hyperglycemia, the macrophage proinflammatory cytokine (IL-1β in combination with IFN-γ and TNF-α), playing an essential role in β cell dysfunction and death [92]. ...
... Experimental DM in rodents is associated with β cell apoptosis that leads to hyperglycemia, the macrophage proinflammatory cytokine (IL-1β in combination with IFN-γ and TNF-α), playing an essential role in β cell dysfunction and death [92]. Hyperglycemia, directly or indirectly (e.g., via oxidative stress or advanced glycation products) increases MMP expression and activity [91]. There is also evidence that both type 1 and type 2 DM are associated with systemic inflammation, and activated leukocytes can release substances that mediate endothelial damage and vascular destabilization (e.g., matrix metalloproteinases) [93][94][95]. ...
Curcumin (CC) is known to have anti-inflammatory and anti-oxidative properties and has already been tested for its efficiency in different diseases including diabetes mellitus (DM). New formulations and route administration were designed to obtain products with higher bioavailability. Our study aimed to test the effect of intraperitoneal (i.p.) administration of liposomal curcumin (lCC) as pre-treatment in streptozotocin(STZ)-induced DM in rats on oxidative stress, liver, and pancreatic functional parameters. Forty-two Wistar-Bratislava rats were randomly divided into six groups (seven animals/group): control (no diabetes), control-STZ (STZ-induced DM —60 mg/100g body weight a single dose intraperitoneal administration, and no CC pre-treatment), two groups with DM and CC pre-treatment (1mg/100g bw—STZ + CC1, 2 mg/100g bw—STZ + CC2), and two groups with DM and lCC pre-treatment (1 mg/100g bw—STZ + lCC1, 2 mg/100g bw—STZ + lCC1). Intraperitoneal administration of Curcumin in diabetic rats showed a significant reduction of nitric oxide, malondialdehyde, total oxidative stress, and catalase for both evaluated formulations (CC and lCC) compared to control group (p < 0.005), with higher efficacy of lCC formulation compared to CC solution (p < 0.002, excepting catalase for STZ + CC2vs. STZ + lCC1when p = 0.0845). The CC and lCC showed hepatoprotective and hypoglycemic effects, a decrease in oxidative stress and improvement in anti-oxidative capacity status against STZ-induced DM in rats (p < 0.002). The lCC also proved better efficacy on MMP-2, and -9 plasma levels as compared to CC (p < 0.003, excepting STZ + CC2 vs. STZ + lCC1 comparison with p = 0.0553). The lCC demonstrated significantly better efficacy as compared to curcumin solution on all serum levels of the investigated markers, sustaining its possible use as adjuvant therapy in DM.
... In addition to this, bosentan administration rather than atorvastatin triggered plaque infiltration by VSMCs, the predominant cellular sources of the ECM [35]. Our findings are of clinical relevance, since the alteration in MMP/TIMP balance has been associated with atherosclerotic plaque vulnerability and adverse cardiovascular events in clinical setting [36,37]. Hence, bosentan seems to possess the potential of reducing plaque vulnerability, even at a lower extent than atorvastatin, by shifting the balance between production and degradation of ECM towards increased intra-plaque collagen and elastin within the atherosclerotic lesions [38]. ...
Bosentan, an endothelin-receptor antagonist (ERA), has potential anti-atherosclerotic properties. We investigated the complementary effects of bosentan and atorvastatin on the progression and composition of the atherosclerotic lesions in diabetic mice. Forty-eight male apoE-/- mice were fed high-fat diet (HFD) for 14 weeks. At week 8, diabetes was induced with streptozotocin and mice were randomized into 4 groups: 1) Control/COG: no intervention. 2) ΒΟG: bosentan 100 mg/kg/day per os. 3) ATG: atorvastatin 20mg/kg/day per os). 4) BO+ATG: Combined administration of bosentan and atorvastatin. The intra-plaque contents of collagen, elastin, monocyte chemoattractant protein-1 (MCP-1), tumor necrosis factor-a (TNF-a), matrix-metalloproteinases (MMP-2,-3,-9), and TIMP-1 concentrations were determined. The percentage of lumen stenosis significantly decreased across all treated groups: BOG: 19.5±2.2%, ATG: 12.8±4.8%, BO+ATG: 9.1±2.7% compared to controls (24.6±4.8%, p<0.001). Both atorvastatin and bosentan significantly increased collagen content and fibrous cap thickness versus COG (p<0.01). All intervention groups reduced the relative intra-plaque concentrations of MCP-1, MMP-3,-9, and increased TIMP-1 compared to COG (p<0.001). Importantly, bosentan showed modest but additive to atorvastatin effects on the latter parameters compared COG (p<0.05). Bosentan treatment in diabetic, atherosclerotic apoE-/- mice delayed the atherosclerosis progression and enhanced plaques’ stability, showing modest but complementary effects with atorvastatin, which are promising in atherosclerotic cardiovascular diseases.
... Scientists are creating nanoparticle compositions with antidiabetic plant components to expand their application. 67,68 Nanoparticle-based herbal medicines have better targeted efficacy, bioavailability, toxicity, and biocompatibility than larger ones. Below are lipid-based and inorganic nanocarrier formulations being tested for diabetic treatment. ...
Diabetes, a chronic metabolic disorder, results in high blood glucose levels due to insufficient insulin production or ineffective insulin utilization. Management entails lifestyle changes, exercise, and medication adherence. Monitoring blood sugar levels, healthy eating, and medication are crucial for controlling diabetes and preventing complications. The illness, currently incurable, necessitates management strategies for regulation. Medical treatments are expensive and require long-term adherence, leading many, especially those from low-income nations, to resort to herbal remedies. However, phytocompounds, though promising, often suffer from limited bioavailability due to poor solubility, permeability, or rapid elimination. Plant nanomedicines offer a promising avenue to address these challenges and alleviate the financial strain on disadvantaged populations. Encapsulated treatments using plant extracts or antidiabetic chemicals at the nanoscale have shown promising results. Our study aims to provide a thorough examination of lipid- and inorganic-based nanoparticulate delivery systems combined with plant extracts or phytocompounds for diabetes management Our analysis will highlight both the advantages and limitations of these systems for future clinical application. Examined studies revealed that nanoparticulate formulations displayed strong antidiabetic effects at lower doses compared to individual plant extracts or phytocompounds. Additionally, nanoparticulate systems have effectively addressed the issue of low bioavailability in herbal medications, showing promise for enhanced therapeutic outcomes.
... VSMC (Vascular Smooth Muscle Cell) proliferation at sites of endothelial cell injury and subsequent lipid deposition play a role in atheroma formation, and MMPs appear to be involved in these processes (16). MMP expression is increased in the atherosclerotic plaque, and activation of MMPs appears to facilitate atherogenesis, platelet aggregation and plaque destabilization (16,17,18). ...
... Stroke patients with diminished collaterals have a rate of worsening four times higher and a better collateral status can be considered an independent predictor of an improved functional outcome [38]. A good collateral circulation was associated also with better functional recovery at 90 days [39]. ...
Cerebral collateral circulation is a network of blood vessels which stabilizes blood flow and maintains cerebral perfusion whenever the main arteries fail to provide an adequate blood supply, as happens in ischemic stroke. These arterial networks are able to divert blood flow to hypoperfused cerebral areas. The extent of the collateral circulation determines the volume of the salvageable tissue, the so-called “penumbra”. Clinically, this is associated with greater efficacy of reperfusion therapies (thrombolysis and thrombectomy) in terms of better short- and long-term functional outcomes, lower incidence of hemorrhagic transformation and of malignant oedema, and smaller cerebral infarctions. Recent advancements in brain imaging techniques (CT and MRI) allow us to study these anastomotic networks in detail and increase the likelihood of making effective therapeutic choices. In this narrative review we will investigate the pathophysiology, the clinical aspects, and the possible diagnostic and therapeutic role of collateral circulation in acute ischemic stroke.
... Notably, MMP2 activity was higher in diabetic patients with PAD compared to diabetic patients without PAD. These results indicate that deregulation of these MMPs and subsequent increase in proteolysis may contribute to the pathogenesis of diabetes vascular complications [200,201]. Importantly, MMP9 serum concentrations (but not MMP2) were previously shown to be increased in patients with cardiovascular disease due to acute myocardial infarction and MMP9 was proposed as a marker of inflammation in this disease [202]. ...
Matrix metalloproteinases (MMPs) are a family of zinc-activated peptidases that can be classified into six major classes, including gelatinases, collagenases, stromelysins, matrilysins, membrane type metalloproteinases, and other unclassified MMPs. The activity of MMPs is regulated by natural inhibitors called tissue inhibitors of metalloproteinases (TIMPs). MMPs are involved in a wide range of biological processes, both in normal physiological conditions and pathological states. While some of these functions occur during development, others occur in postnatal life. Although the roles of several MMPs have been extensively studied in cancer and inflammation, their function in metabolism and metabolic diseases have only recently begun to be uncovered, particularly over the last two decades. This review aims to summarize the current knowledge regarding the metabolic roles of metalloproteinases in physiology, with a strong emphasis on adipose tissue homeostasis, and to highlight the consequences of impaired or exacerbated MMP actions in the development of metabolic disorders such as obesity, fatty liver disease, and type 2 diabetes.
... There is limited information about the role of TIMPs in the pathophysiology of T2D and obesity [44]. Most studies investigated their role in complications of T2D, such as cardiovascular diseases [45], foot ulcerations [46], or diabetic nephropathy [47]. A clinical study found that pro-MMP-9 levels were elevated, whereas TIMP-1 and TIMP-2 levels were reduced, in patients with T2D, compared to controls with NGR. ...
Previously, we found that human pancreatic preadipocytes (PPAs) and islets influence each other and that the crosstalk with the fatty liver via the hepatokine fetuin-A/palmitate induces inflammatory responses. Here, we examined whether the mRNA-expression of pancreatic extracellular matrix (ECM)-forming and -degrading components differ in PPAs from individuals with normal glucose regulation (PPAs-NGR), prediabetes (PPAs-PD), and type 2 diabetes (PPAs-T2D), and whether fetuin-A/palmitate impacts ECM-formation/degradation and associated monocyte invasion. Human pancreatic resections were analyzed (immuno)histologically. PPAs were studied for mRNA expression by real-time PCR and protein secretion by Luminex analysis. Furthermore, co-cultures with human islets and monocyte migration assays in Transwell plates were conducted. We found that in comparison with NGR-PPAs, TIMP-2 mRNA levels were lower in PPAs-PD, and TGF-β1 mRNA levels were higher in PPAs-T2D. Fetuin-A/palmitate reduced fibronectin, decorin, TIMP-1/-2 and TGF-ß1 mRNA levels. Only fibronectin was strongly downregulated by fetuin-A/palmitate independently of the glycemic status. Co-culturing of PPAs with islets increased TIMP-1 mRNA expression in islets. Fetuin-A/palmitate increased MMP-1, usherin and dermatopontin mRNA-levels in co-cultured islets. A transmigration assay showed increased monocyte migration towards PPAs, which was enhanced by fetuin-A/palmitate. This was more pronounced in PPAs-T2D. The expression of distinct ECM components differs in PPAs-PD and PPAs-T2D compared to PPAs-NGR, suggesting that ECM alterations can occur even in mild hyperglycemia. Fetuin-A/palmitate impacts on ECM formation/degradation in PPAs and co-cultured islets. Fetuin-A/palmitate also enhances monocyte migration, a process which might impact on matrix turnover.
... This is true for many organs, including the periodontium, for CMs implanted in diabetic animals (our studies [43][44][45][46]) and for other degradable devices implanted in diabetic animals [34][35][36]. Increased lysis of various tissues in diabetics accompanies the exaggerated inflammation [14][15][16][17][18][19][20][63][64][65]. By inference, this is corroborated by our findings that addition of tetracycline (anti-collagenolytic) and hyaluronic acid (anti-inflammatory) to the membranes mitigated their excessive resorption in diabetic rats (our studies [43][44][45][46]). ...
Uncontrolled diabetes is characterized by aberrant inflammatory reactions and increased collagenolysis. We have reported that it accelerates the degradation of implanted collagen membranes (CM), thus compromising their function in regenerative procedures. In recent years, a group of physiological anti-inflammatory agents called specialized pro-resolving lipid mediators (SPMs) have been tested as a treatment for various inflammatory conditions, either systemically or locally, via medical devices. Yet, no study has tested their effect on the fate of the biodegradable material itself. Here, we measured the in vitro release over time of 100 or 800 ng resolvin D1 (RvD1) incorporated into CM discs. In vivo, diabetes was induced in rats with streptozotocin, while buffer-injected (normoglycemic) rats served as controls. Resolvins (100 or 800 ng of RvD1 or RvE1) were added to biotin-labeled CM discs, which were implanted sub-periosteally over the calvaria of rats. Membrane thickness, density, and uniformity were determined by quantitative histology after 3 weeks. In vitro, significant amounts of RvD1 were released over 1–8 days, depending on the amount loaded. In vivo, CMs from diabetic animals were thinner, more porous, and more variable in thickness and density. The addition of RvD1 or RvE1 improved their regularity, increased their density, and reduced their invasion by the host tissue significantly. We conclude that addition of resolvins to biodegradable medical devices can protect them from excessive degradation in systemic conditions characterized by high degree of collagenolysis.
... However, whether this alteration in catalase levels is related to the decrease in APOA1 On the other hand, hyperglycemia in diabetic patients can increase the expression of MMP in macrophages and endothelial cells due to oxidative damage. MMPs are known as endopeptidases that target extracellular matrix proteins, some of which play an important role in remodeling venous tissue (33,34). Due to its role in diabetes, MMP9 is one of the most interesting MMP family members. ...
... It seems that genetic susceptibility plays a role in developing such complications [5]. It has been postulated that zinc-dependent endopeptidases called matrix metalloproteinases (MMPs), are very important in remodelling the extracellular matrix, and therefore they have an impact on the onset and progression of diabetic vascular complications [6][7]. The regulation of MMPs is very complex, depending not only on the regulation of their tissue inhibitors, but also on the regulation of MMP gene expressions by transcriptional factors and epigenetic modifications [8]. ...
Vascular complications are the leading cause of increased morbidity and mortality of diabetic patients. It has been postulated that matrix metalloproteinases MMP-2 and MMP-9 , zinc-dependent endopeptidases through remodeling of the extracellular matrix, can contribute to the onset and progression of diabetic vascular complications. The aim of our study was to assess whether there is a major difference in single nucleotide polymorphisms in the MMP-2 (at position -1306C˃T) and MMP-9 (at position -1562C˃T) gene in type 2 diabetic patients and healthy controls and to determine whether there is an association of these gene variants with the presence of microvascular complications in diabetic patients. Our study included 102 type 2 diabetes patients and a control group which was comprised of 56 healthy controls. All diabetic patients were screened for microvascular diabetes complications. Genotypes were detected by polymerase chain reactions followed by restriction analyses with specific endonucleases and their frequencies were determined. The MMP-2 variant -1306C>T showed a negative correlation with type 2 diabetes (p=0.028). It was also shown that the presence of the -1306C allele increases the probability of developing type 2 diabetes. This was a 2.2 fold increase and that the -1306 T allele has a protective role in regards to type 2 diabetes. The MMP-2 variant -1306T showed a negative correlation with diabetic polyneuropathy (p=0.017), meaning that allele-1306T has a protective role in regards to diabetic polyneuropathy while the presence of allele -1306C increases the probability of developing diabetic polyneuropathy by 3.4 fold. Our study showed that the MMP-2 gene variant (-1306C) doubles the risk of developing type 2 diabetes, and for the first time an association of this gene variant and the presence of diabetic polyneuropathy was shown.
... Так, хорошо известно, что гликирование белков, наблюдаемое у больных сахарным диабетом, приводит к изменению их свойств [14], это касается и ММП [19,20]. Однако проблема взаимоотношений между ММП и их ингибиторами до сих пор остается малоизученной и требует дальнейшего изучения [18,21]. ...
The aim of the study was to test the hypothesis on the possible reason for the decrease in the activity of matrix metalloproteinases (MMPs) as a consequence of the high concentration of their tissue inhibitors (TIMPs) in the blood serum of patients with type 2 diabetes mellitus (T2DM). Material and methods. In the experimental part of the article, we used the blood serum of patients under observation in the clinic of the Federal Research Center of Fundamental and Translational Medicine. According to the content of glycated hemoglobin (HbA1С) in blood serum, the patients were divided into 3 groups: at the stage of compensation (6.0–6.5 % HbA1С), at the stage of subcompensation (6.6–7.0 % HbA 1С) and decompensation (> 7.0 % HbA1С). The activity of MMPs 2 and 7 in blood serum samples was measured by a fluorimetric method using a fluorescent substrate specific for these MMPs. The concentration of TIMP-1 (inhibitor of all non-membrane-bound MMPs) and TIMP-2 (active against MMP-2 and -7) in blood serum were determined by enzyme immunoassay. Results and discussion. In patients with T2DM, the MMP-2 and -7 activities decreased, more pronouncedly at the stage of decompensation. An increase in the concentration of TIMP-1 was observed in the serum of all patients, while no significant changes in the content of TIMP-2 were found. At the stage of decompensation, a decrease in MMP activity was accompanied by a decrease in the content of insulin, C-peptide and a corresponding increase in the level of proinsulin. An inverse correlation was found between the concentrations of TIMP-1 and insulin in patients at the stage of decompensation of T2DM. It is assumed that the activity of MMP-2 and -7, in comparison with their inhibitors, forms stronger correlations with the parameters of carbohydrate metabolism.
... TIMPs are found to be reduced in diabetic chronic wounds which aggravates the problem [27][28][29][30]. The imbalance between MMP and TIMP levels is a major cause of hyperglycemia, hyperlipidemia and hypertension in diabetic ulcers and chronic wounds [31,32]. The overexpression of MMP-13 and MMP-9 is linked to a high concentration of glucose at the wound site [33]. ...
1. Diabetic chronic wounds, mainly foot ulcers, constitute one of the most common complications of poorly managed diabetes mellitus. The most typical reasons are insufficient glycemic management, latent neuropathy, peripheral vascular disease, and neglected foot care. In addition, it is a common cause of foot osteomyelitis and amputation of the lower extremities. Patients are admitted in larger numbers attributable to chronic wounds compared to any other diabetic disease. In the United States, diabetes is currently the most common cause of non-traumatic amputations. Approximately five percent of diabetics develop foot ulcers, and one percent require amputation. Therefore, it is necessary to identify sources of lead with wound-healing properties. Redox imbalance due to excessive oxidative stress is one of the causes for the development of diabetic wounds. Antioxidants have been shown to decrease the progression of diabetic neuropathy by scavenging ROS, regenerating endogenous and exogenous antioxidants, and reversing redox imbalance. Matrix metalloproteinases (MMPs) play vital roles in numerous phases of the wound healing process. Antioxidant and fibroblast cell migration activity of Marantodes pumilum (MP) crude extract has previously been reported. Through their antioxidant, epithelialization, collagen synthesis, and fibroblast migration activities, the authors hypothesise that naringin, eicosane and octacosane identified in the MP extract may have wound-healing properties. 2. The present study aims to identify the bioactive components present in the dichloromethane (DCM) extract of M. pumilum and evaluate their antioxidant and wound healing activity. Bioactive components were identified using LCMS, HPTLC and GCMS. Excision wound on STZ-induced diabetic rat model, human dermal fibroblast (HDF) cell line and colorimetric antioxidant assays were used to evaluate wound healing and antioxidant activities, respectively. Molecular docking and pkCMS software would be utilised to predict binding energy and affinity, as well as ADME parameters. 3. Naringin (NAR), eicosane (EIC), and octacosane (OCT) present in MP displayed antioxidant action and wound excision closure. Histological examination HDF cell line demonstrates epithelialization, collagen production, fibroblast migration, polymorphonuclear leukocyte migration (PNML), and fibroblast movement. The results of molecular docking indicate a substantial attraction and contact between MMPs. pkCMS prediction indicates inadequate blood-brain barrier permeability, low toxicity, and absence of hepatotoxicity. 4. Wound healing properties of (NEO) naringin, eicosane and octacosane may be the result of their antioxidant properties and possible interactions with MMP.
... Metalloproteinase expression is always related to cell apoptosis in many pathologies. Hyperglycaemia is believed to induce the production of metalloproteinases, which can increase the risks of vascular complications [67,68]. ...
Diabetes mellitus is a prevalent metabolic syndrome that is associated with high blood glucose levels. The number of diabetic patients is increasing every year and the total number of cases is expected to reach more than 600 million worldwide by 2045. Modern antidiabetic drugs alleviate hyperglycaemia and complications that are caused by high blood glucose levels. However, due to the side effects of these drugs, plant extracts and bioactive compounds with antidiabetic properties have been gaining attention as alternative treatments for diabetes. Natural products are biocompatible, cheaper and expected to cause fewer side effects than the current antidiabetic drugs. In this review, various nanocarrier systems are discussed, such as liposomes, niosomes, polymeric nanoparticles, nanoemulsions, solid lipid nanoparticles and metallic nanoparticles. These systems have been applied to overcome the limitations of the current drugs and simultaneously improve the efficacy of plant-based antidiabetic drugs. The main challenges in the formulation of plant-based nanocarriers are the loading capacity of the plant extracts and the stability of the carriers. A brief review of lipid nanocarriers and the amphipathic properties of phospholipids and liposomes that encapsulate hydrophilic, hydrophobic and amphiphilic drugs is also described. A special emphasis is placed on metallic nanoparticles, with their advantages and associated complications being reported to highlight their effectiveness for treating hyperglycaemia. The present review could be an interesting paper for researchers who are working in the field of using plant extract-loaded nanoparticles as antidiabetic therapies.
... Studies have confirmed MMP-9 plasma concentrations predicted stroke and cardiovascular death in patients with ≥ 50% carotid stenosis, although not independently (Eldrup et al. 2006;Jefferis et al. 2010). The positive predictive value of MMP-9 was significantly enhanced when combined with other members of the MMP family (MMP-7, MMP-8 and MMP-12 and their tissue inhibitor TIMP-1) (Jiang et al. 2004;NP Kadoglou and Liapis 2004) or with plaque echolucency (NP Kadoglou et al. 2005). ...
Background
Atherosclerosis is a chronic lipid-driven inflammatory disease with infiltration of low-density lipoprotein and is considered as the pivotal step in plaque formation. The aim of the review is to get into the fine details of pathophysiologic mechanisms responsible for atherosclerosis with atherosclerotic lesion classification. It also provides a summary of current biomarkers other than the traditional risk factors so that new treatment modalities can emerge and reduce the morbidity and mortality associated with atherosclerosis.
Main body
In the classification of atherosclerosis made by American Heart Association (AHA), AHA Type I lesion is the earliest vascular change described microscopically. AHA Type II lesion is primarily composed of abundant macrophages. AHA Type III lesion is the earliest of progressive lesions, while AHA Type IV lesion consists of an acellular necrotic core. Various biomarkers are implicated in different stages of the pathophysiological mechanism of plaque formation and evolution. C Reactive Protein plays a direct role in promoting the inflammatory component of atherosclerosis. Fibrinogen was demonstrated to be elevated among patients with acute thrombosis. Higher leukocyte count is associated with a greater cardiovascular risk. Cytokines have been implicated in atheroma formation and complications. High rates of protease activated receptor expression are also induced by interleukin-6 secretion in atherosclerotic lesions and areas of vascular tissue injury. Cluster of differentiation 40 receptor and its ligand have been also detected in atherosclerotic plaques. Osteopontin, acidic phosphoprotein, and osteoprotegerin have emerged as novel markers of atherosclerotic plaque composition. There are also overproductions of matrix metalloproteinases in the rupture-prone regions and promote lipid-necrotic core formation in the atherosclerotic plaque. Myeloperoxidase has been proposed as a marker of plaque instability. Oxidized low-density lipoprotein receptor 1 provides a route of entry for oxidized low-density lipoprotein into the endothelium. A human atherosclerotic lesion also expresses lipoprotein-associated phospholipase A 2 .
Short conclusion
Atherosclerotic plaques are the battlefield between an unbalanced immune response and lipid accumulation in the intima of arteries. Most of the biomarkers associated with atherosclerosis are indicators of inflammatory response and will also be used for medical purposes.
... There is an increase in the expression of MMP in smooth muscle cells and macrophages in atherosclerosis, which leads to the destabilization of the atherosclerotic process in the vascular wall. A particularly high level of MMP is observed in the accumulation of foam cells area and the area of the shoulder of the plaque [3][4][5][6]. MMPs are involved in the development and progression of atherosclerosis, and changes in their level are associated with an increased risk of cardiovascular morbidity and mortality [7][8][9]. ...
This work is aimed at studying the relationship of matrix metalloproteinases with calcification of the coronary arteries. The study included 78 people with coronary heart disease (CHD) and 36 without CHD. Blood and samples of coronary arteries obtained as a result of endarterectomy were examined. Serum levels of metalloproteinases (MMP) MMP-1, MMP-2, MMP-3, MMP-7, MMP-9, MMP-10, MMP-12, and MMP-13 were determined by multiplex analysis. In blood vessel samples, MMP-1, MMP-3, MMP-7, and MMP-9 were determined by enzyme immunoassay; MMP-9 expression was evaluated by immunohistochemistry. Patients with CHD had higher serum levels of MMP-1, MMP-7, and MMP-12. Blood levels of MMP-1 and MMP-3 were associated with calcium levels, MMP-9 with osteoprotegerin and osteonectin, MMP-7 and MMP-10 with osteoprotegerin, MMP-12 with osteocalcin, and MMP-13 with osteopontin. Calcified plaques had higher levels of MMP-1 and MMP-9 compared to plaques without calcification. The relative risk of coronary arteries calcification was associated with MMP-9, which is confirmed by the results of immunohistochemistry. The results obtained indicate the participation of some MMPs, and especially MMP-9, in the calcification processes. The study can serve as a basis for the further study of the possibility of using MMP-1, MMP-7 and MMP-12 as potential biomarkers of CHD.
... 8 Increased MMP activity has been correlated with increased matrix turnover in atherosclerosis, especially in diabetic nephropathy, with glomerular basement membrane thickening. 9 MMPs are zinc-and calcium-dependent endopeptidases, able to degrade and rebuild proteins like collagen, elastin, gelatine and casein. 10 Increased plasma levels of MMPs have been observed in people with type 1 diabetes, while increased levels of serum MMP-9, as well as increased MMP-9-to-Tissue inhibitor of metalloproteinase (TIMP) ratio, have been related to retinopathy. ...
Background
Tissue inhibitor of metalloproteinase-1 (TIMP-1) has been suggested as a marker for abnormal regulation of tissue remodelling in type 1 diabetes. Metalloproteinase-9 (MMP-9) has been associated with matrix turnover, and Neutrophil gelatinase associated lipocalin (NGAL) is a marker of tubular injury in diabetic nephropathy. The aim was to analyse these biomarkers to unmask early diabetic complications.
Methods
Thirty-three type 1 diabetes patients, aged 20–35 years, and disease duration 20 ± 5.3 years were included. Along with clinical examination, neurophysiological measurements, routine biochemistry, plasma concentrations of TIMP-1, MMP-9 and NGAL were determined with immunoenzymatic techniques.
Results
TIMP-1 correlated with abnormal unilateral and bilateral vibratory sense foot perception ( r = −0.49 and r = −0.51, respectively), foot neuropathy impairment assessment score (NIA; r = −0.55), neuropathy symptom assessment score ( r = 0.42), microalbuminuria ( r = 0.50) and eGFR ( r = −0.45). MMP-9 correlated with impaired foot NIA ( r = 0.51). Multiple regression analysis showed an association for TIMP-1 ( p = 0.004) with impaired neurophysiological examinations and renal dysfunction along with NGAL ( p = 0.016 and p = 0.015 respectively).
Conclusions
This study suggests that plasma levels of TIMP-1, MMP-9 and NGAL may serve as useful biomarkers in unravelling subclinical neuropathy and nephropathy in type 1 diabetes.
... In diabetes, they escalated inflammation, endothelial function impairment, vascular remodelling as well as thrombus generation [120]. The loss of balance among MMPs along with their inhibitors demonstrated in diabetes is correlated with the generation along with destability of atherosclerotic plaques [121]. Hence, endothelial function impairment is a main aetiological factor in aiding in chances of CVD in T1DM as well as T2DM subjects as demonstrated In figure 3. ...
Earlier we have already evaluated in detail the initiation of atherosclerosis in both type1 diabetes mellitus( T1DM) as well as type2 diabetes mellitus ( T2DM) and details of acetylation end-glycation- products(AGE), receptor for AGE(RAGE) role of neutrophil extracellular trap formation and influence on cardiovascular disease (CVD) .Further we reviewed how CVD is avoided with better Sodium Glucose Transporter 2( SGLT2) inhibitors in both T1DM as well as T2DM. Further we have emphasized on use of weight neutral hypoglycaemics to reduce the morbidity with escalation of diabesity. Also we reviewed importance of microRNA’S, inHDL transport, significance of use of proprotein convertase subtilisin /kexin type9(PCSK9) inhibitors Here we tried to concentrate on reducing same by understanding how this DM might influence the cardiovascular System( CVS) alterations as well as changes caused by them in the amounts of plasma proteins as well as metal ions, changed lipid metabolism(causing changed metabolic control), cardiac lipotoxicity as well as atherosclerosis, endothelial impairment, platelets hyperreactivation along with the existence of procoagulant particles in the blood in aetiopathogenesis of CVD with lipid metabolism, sphingosine-1 phosphate ;alteration in coagulation parameters in both T1DM as well as T2DM. Thus we conducted a systematic review regarding same with utilization of search engines like pubmed, MEDLINE, Google scholar, Web of Science, scopus, Embase, using MeSH terms like fibrinogen; thrombin; antithrombin; antiplasmin; plasminogen activator inhibitor -1 (PAI-1), von Willebrand factor ; factor V, factor VII, factor IX, factor X factor, factor XII,tissue factor, metal ions like Ca2+ATPase, Zn2+, Cu2+, Mg2+, Fe3+ iron, platelet hyperactivation; platelet microparticles; complement alteration; endothelial impairment role of lipid metabolism LDL levels, High density lipoproteins High density lipoproteins (HDL) levels in type1 diabetes mellitus as well as type2 diabetes mellitus as well as from 1980’s till 2029 till date. We found a total of 650 articles out of which we selected 167 articles for this review. No meta-analysis was done. Thus we consider each step by step in influencing CVS risk and what prophylaxis is needed to avoid the CVD complications in each of DM along with influence in COVID mortality.
Keywords : T1DM; (T2DM; cardiovascular disease; hypercoagulability in diabetes; platelet hyperactivation
... In diabetes, they escalated inflammation, endothelial function impairment, vascular remodelling as well as thrombus generation [120]. The loss of balance among MMPs along with their inhibitors demonstrated in diabetes is correlated with the generation along with destability of atherosclerotic plaques [121]. Hence, endothelial function impairment is a main aetiological factor in aiding in chances of CVD in T1DM as well as T2DM subjects as demonstrated In figure 3. ...
Earlier we have already evaluated in detail the initiation of atherosclerosis in both type1 diabetes mellitus(T1DM) as well as type2 diabetes mellitus (T2DM) and details of acetylation end-glycation-products(AGE), receptor for AGE(RAGE) role of neutrophil extracellular trap formation and influence on cardiovascular disease (CVD) .Further we reviewed how CVD is avoided with better Sodium Glucose Transporter 2(SGLT2) inhibitors in both T1DM as well as T2DM. Further we have emphasized on use of weight neutral hypoglycaemics to reduce the morbidity with escalation of diabesity. Also we reviewed importance of microRNA'S, inHDL transport, significance of use of proprotein convertase subtilisin /kexin type9(PCSK9) inhibitors Here we tried to concentrate on reducing same by understanding how this DM might influence the cardiovascular System(CVS) alterations as well as changes caused by them in the amounts of plasma proteins as well as metal ions, changed lipid metabolism(causing changed metabolic control), cardiac lipotoxicity as well as atherosclerosis, endothelial impairment, platelets hyperreactivation along with the existence of procoagulant particles in the blood in aetiopathogenesis of CVD with lipid metabolism, sphingosine-1 phosphate ;alteration in coagulation parameters in both T1DM as well as T2DM. Thus we conducted a systematic review regarding same with utilization of search engines like pubmed, MEDLINE, Google scholar, Web of Science, scopus, Embase, using MeSH terms like fibrinogen; thrombin; antithrombin; antiplasmin; plasminogen activator inhibitor-1 (PAI-1), von Willebrand factor ; factor V, factor VII, factor IX, factor X factor, factor XII,tissue factor, metal ions like Ca2+ATPase, Zn2+, Cu2+, Mg2+, Fe3+ iron, platelet hyperactivation; platelet microparticles; complement alteration; dendothelial impairment role of lipid metabolism LDL levels, High density lipoproteins High density lipoproteins (HDL) levels in type1 diabetes mellitus as well as type2 diabetes mellitus as well as from 1980's till 2029 till date. We found a total of 650 articles out of which we selected 167 articles for this review. No meta-analysis was done. Thus we consider each step by step in influencing CVS risk and what prophylaxis is needed to avoid the CVD complications in each of DM along with influence in COVID mortality.
... compared with baseline, 68 and data suggest that increased blood glucose levels can activate TGF-β. 69 Decorin, an inhibitor of TGF-β1 that is upregulated in people with Peyronie's disease, 35 was also upregulated by 650% ± 60% of control values in the kidney tissue of people with diabetic nephropathy compared with healthy kidney tissue. 55 In advanced stages of diabetic nephropathy, decorin deposition was found in fibrotic areas and colocalized with type I collagen. ...
Introduction
Fibrosis is characterized by dysregulation and accumulation of extracellular matrix. Peyronie's disease and Dupuytren disease are fibroproliferative disorders of the tunica albuginea of the penis and fascia of the hand, respectively. Chronic hyperglycaemia due to diabetes mellitus can also lead to tissue injury and fibrosis. A meta‐analysis has shown a relationship between Dupuytren disease and diabetes (overall odds ratio, 3.1; 95% confidence interval, 2.7‐3.5). This review explores commonalities in the pathogenesis of Peyronie's disease, Dupuytren disease and diabetes.
Methods
A search of the PubMed database was conducted using the search terms “diabetes” AND “Peyronie's disease”; and “diabetes” AND “Dupuytren.”
Results
Genome‐wide association and gene expression studies conducted with tissue from people with Peyronie's disease or Dupuytren disease identified signalling pathways associated with wingless‐type mammary‐tumour virus integration site signalling, extracellular matrix modulation and inflammation. Biochemical studies confirmed the importance of these pathways in the pathogenesis of fibrosis with Peyronie's disease and Dupuytren disease. Dysregulation of matrix metalloproteinase activity associated with extracellular matrix breakdown was implicated in fibroproliferative complications of diabetes and in the aetiology of Peyronie's disease and Dupuytren disease. A notable percentage of people with diabetes have comorbid Peyronie's disease and/or Dupuytren disease.
Conclusions
Studies have not been performed to identify fibroproliferative pathways that all 3 conditions might have in common, but data suggest that common pathways are involved in the fibroproliferative processes of Peyronie's disease, Dupuytren disease, and diabetes.
... The overexpression of MMP-13 and MMP-9 is associated with high glucose concentration at wound site [125]. The imbalance between MMP and TIMP level is a major cause of hyperglycemia, hyperlipidemia and hypertension during the condition of chronic wounds/diabetic ulcers [126,127]. In the state of chronic wounds, the migration of inflammatory cells is followed by imbalanced fibroblast clotting which lead to secrete the ECM proteins. ...
Management of diabetic foot remains a major challenge for healthcare system. Though wound healing is a multiphase process and involved multiple biomarkers that acts in stepwise manner, pathophysiology diabetic foot ulcers is still not much clear and need standardization. Matrix metalloproteinases (MMPs) are often linked with non-healing characteristic of diabetic foot ulcers. They play vital roles in various phases of healing process. Major functions are removal of damaged extracellular matrix in inflammatory phase, breakdown of capillary basement membrane prior to angiogenesis and facilitation in fibroblast migration during proliferation phase. For efficient healing, these enzymes are needed in certain amount only. Imbalance of these enzymes leads to excessive degradation which has been linked with the non-healing nature of diabetic ulcers. This chapter will shed light on the role of MMP’s in various phases of wound healing and the inhibitors of MMP’s from natural as well as synthetic origin. It would help researchers and physicians to the understand nature of diabetic foot more clearly and design of strategies for diabetic foot management.
... Amongst the large family of MMPs, MMP-2 (or Gelatinase-A), which is constitutively expressed in the heart and vessel wall, and MMP-9 (or Gelatinase-B), an inducible protease whose presence in tissues is associated with the infiltration of inflammatory cells, when changed in their activities or concentrations, contribute to the proteolysis of structural and contractile proteins of ECM, cardiomyocytes, and VSMCs, leading to maintenance of high BP and CVD development and progression. 3,11,[23][24][25][26] Starting from this evidence, many studies and clinical trials 25-28 observed a notable higher MMP-9 serum levels in hypertensive patients compared to normotensive controls. [27][28][29][30] In the Anglo-Scandinavian Cardiac Outcomes Trial (ASCOT) study, Tayebjee and collegues 29 demonstrated that in uncontrolled hypertensive patients (eg, stage 3 of HT) circulating plasma concentrations of MMP-9 and TIMP-1, measured by ELISA, were significantly higher compared to normotensive controls at baseline. ...
Matrix metalloproteinases (MMPs) are important extracellular enzymes involved in many physiological and pathological processes. Changes in the activity and concentration of specific MMPs, as well as the unbalance with their inhibitors (tissue inhibitors of metalloproteinases – TIMPs), have been described as a part of the pathogenic cascade promoted by arterial hypertension. MMPs are able to degrade various protein substrates in the extracellular matrix, to influence endothelial cells function, vascular smooth muscle cells migration, proliferation and contraction, and to stimulate cardiomyocytes changes. All these processes can be activated by chronically elevated blood pressure values. Animal and human studies demonstrated the key function of MMPs in the pathogenesis of hypertension-mediated vascular, cardiac, and renal damage, besides age and blood pressure values. Thus, the role of MMPs as biomarkers of hypertension-mediated organ damage and potential pharmacological treatment targets to prevent further cardiovascular and renal complications in hypertensive population is increasingly supported. In this review, we aimed to describe the main scientific evidence about the behavior of MMPs in the development of vascular, cardiac, and renal damage in hypertensive patients.
... Matrix metalloproteinases (MMPs) comprise a broad group of zinccontaining calcium-dependent endopeptidases that regulate, among other processes, extracellular matrix degradation, cell migration, apoptosis, and wound healing [18]. Under normal conditions, there is a balance between the MMPs and their inhibitors, called tissue inhibitors of metalloproteinases (TIMPs). ...
Background
Mental stress (MS) is related to endothelial dysfunction in overweight/obese men. It is believed that the pro-oxidant profile, associated with an imbalance in the vascular remodeling process, may contribute to deleterious effects of MS on endothelial function. However, it is unknown whether administration of ascorbic acid (AA), a potent antioxidant, can prevent oxidative and remodeling dysfunction during MS in these subjects.
Methods
Fourteen overweight/obese grade I men (27 ± 7 years; 29.7 ± 2.6 kg·m⁻²) underwent the Stroop Color Word Test for 5 min to induce MS after AA (3 g) or placebo (PL, 0.9% NaCl) intravenous infusions. Venous blood samples were collected at baseline and the last minute of MS to measure nitrite concentration (chemiluminescence), protein carbonylation, thiobarbituric acid reactive substances (TBARS) and catalase activity (colorimetric assays), superoxide dismutase (SOD; immunoenzymatic assay), activities of active/inactive (pro) forms of metalloproteinases-9 and -2 (MMP; zymography) and its respective tissue inhibitors concentration (TIMP-1 and TIMP-2; immunoenzymatic assays).
Results
At baseline, MMP-9 activity (p < 0.01), the MMP-9/proMMP-9 ratio (p = 0.02) and TIMP-1 concentration (p = 0.05) were reduced, whereas proMPP-9 activity was increased (p = 0.02) after AA compared to PL infusion. After PL infusion, MS increased protein carbonylation (p < 0.01), catalase (p < 0.01), and the MMP-9/proMMP-9 ratio (p = 0.04) when compared to baseline. AA infusion reduced protein carbonylation (p = 0.02), MMP-9 activity (p < 0.01), and MMP-9/pro-MMP-9 ratio (p < 0.01), while SOD (p = 0.04 vs baseline), proMPP-9 (p < 0.01 vs PL), MMP-2 (p < 0.01 vs PL) and TIMP-2 (p = 0.02 vs baseline) remained elevated during MS.
Conclusions
AA appears to minimize the oxidative imbalance and vascular remodeling induced by MS.
... In diabetes, they increase inflammation, endothelial dysfunction, vascular remodelling and thrombus formation [155,156]. The imbalance of matrix metalloproteinases and their inhibitors observed in diabetes is associated with the formation and destabilisation of atherosclerotic plaques [157,158]. Thus, endothelial dysfunction is a major factor contributing to the risk of cardiovascular disease in individuals with T1DM and T2DM, as summarised in Figure 3. The changes in inflammation, oxidative stress and blood levels of glucose, insulin and lipids associated with T1DM and T2DM cause endothelial dysfunction, which itself results in an increase in the risk of cardiovascular disease. ...
Diabetes (both type-1 and type-2) affects millions of individuals worldwide. A major cause of death for individuals with diabetes is cardiovascular diseases, in part since both types of diabetes lead to physiological changes that affect haemostasis. Those changes include altered concentrations of coagulatory proteins, hyper-activation of platelets, changes in metal ion homeostasis, alterations in lipid metabolism (leading to lipotoxicity in the heart and atherosclerosis), the presence of pro-coagulatory microparticles and endothelial dysfunction. In this review, we explore the different mechanisms by which diabetes leads to an increased risk of developing coagulatory disorders and how this differs between type-1 and type-2 diabetes.
... MMPs levels have been elevated in patients with metabolic syndrome or diabetes mellitus (types 1 and 2), which can contribute to a higher incidence of diabetic complications (63)(64)(65). Koromantzos et al. examined the effects of conservative treatment of periodontal disease, at the levels of high-sensitivity C reactive protein, d-8-iso prostaglandins as markers of oxidative stress and MMP-2 and MMP-9, in patients with diabetes (66). The results showed that conservative therapy in patients with moderate to advanced periodontal disease and diabetes did not lead to a statistically significant effect on the levels of examined markers. ...
Diabetes mellitus, a chronic disease considered by the World Health Organization to be an epidemic, is now recognized as one of the factors behind the onset of periodontal disease. The connection between periodontal disease, which is an irreversible inflammatory disease of the supporting tissue of the teeth, and systemic diseases is reflected in the existence of common risk factors, subgingival dental biofilm, as a constant source of proinflamma-tory cytokines synthesized intensely in inflammatory periodontium. Diabetes mellitus leads to increased oxidative stress in periodontal tissues causing worsening of the disease and periodontopathy exacerbates deficiency of pancreatic β-cells. The most important role in primary inflammatory response in the pathogenesis of periodontopathy is played by neutrophils. Neutrophils cause periodontium destruction by the release of enzymes (matrix metalloproteinases), cytotoxic substances (free radicals, reactive oxygen and nitrogen species) and the expression of membrane receptors. Matrix metalloproteinases within the “protease network” are critical to many physiological and pathological processes, including immunity, inflammation, bone resorption and wound healing. Matrix metalloproteinases levels are elevated in patients with metabolic syndrome and diabetes mellitus, which may contribute to more frequent complications. In this paper, the review of available literature data shows the correlation between periodontal disease and diabetes mellitus, as well as the role of matrix metalloproteinases and oxidative stress in these. In this regard, determining the value of matrix metalloproteinases may be helpful in the diagnosis of periodontal disease complicated by diabetes mellitus. Also, the parameters of oxidative stress could help to clarify the mechanisms of pathogenesis and etiology of periodontal disease, or indicate the potential benefit of antioxidant supplementation in these individuals. As the role of matrix metalloproteinases has not been fully clarified in the pathogenesis of periodontopathy, additional studies will be needed to indicate their importance.
... MMPs are also involved in the development of type 1 and type 2 diabetes (DM) [17]. In more than half of patients with type 2 diabetes, coronary artery disease develops [18,19]. ...
Background:
Arterial hypertension (HT) is a serious and prevalent epidemiological factor in the development of coronary artery disease (CAD). Metalloproteinases (MMPs), especially MMP-2 and MMP-9, and their natural endogenous tissue inhibitors (TIMPs) are involved in the pathogenesis of HT and its complications. MMPs are also involved in the development of diabetes (DM), a risk factor for CAD. The aim of the study was to explore the influence of CAD, HT, and DM on changes in plasma levels of MMP-2 and MMP-9 and their inhibitor TIMP-4.
Methods and results:
The study involved 70 patients with stable CAD admitted for coronary angiography and 15 healthy subjects. Whole blood samples were collected prior to angiography. MMP-2, MMP-9, and TIMP-4 levels in plasma were estimated using ELISA tests. CAD patients showed a significantly increased level of TIMP-4 and decreased level of MMP-2 in comparison to healthy controls (p=0.011 and p=0.037, respectively). Concentration of MMP-2, MMP-9, and TIMP-4 did not differ in the group with and without hypertension. Patients with DM presented higher MMP-2 level than patients without DM (p < 0.001). Multiple regression analysis of the influence of independent variables such as CAD stage, DM, and HT on MMP-2, MMP-9, and TIMP-4 showed that only DM was independently associated with a higher level of MMP-2 (β = 0.42, R2 = 0.17, p < 0.001).
Conclusion:
Data showed that patients with CAD presented higher TIMP-4 and lower MMP-2 concentration regardless of HT and DM. HT had no effect on MMP-2, MMP-9, and TIMP-4 levels in serum. DM was independently associated with higher MMP-2 concentration; however, co-occurrence of CAD and DM was associated with the balance in the MMP-2 level. Concentration of MMP-9 did not change significantly in any of the analysed groups.
... Although cerebrovascular accidents are among the primary causes of mortality in patients with DM (33) and diabetes-related cognitive dysfunction has long been recognized (20) , only a few studies have investigated the effects of diabetes on the vasculature of the CNS. Microvascular complications of diabetes mellitus include diminished perfusion, abnormal endothelial proliferation, and increased permeability (16,33) . The underlying mechanism is not clearly understood; one of the potential causes may be alteration of the blood-brain barrier (BBB) (22) . ...
Background: Reperfusion following ischemia can lead to more injuries than ischemia itself especially in diabetic patients. The aim of this study was to evaluate the effect of dexmedetomidine on ischemia-reperfusion injury (IRI) in rats with have hepatic IRI and diabetes mellitus. Methodology: Twenty-eight Wistar Albino rats were randomised into four groups as control (C), diabetic (DC), diabetic with hepatic ischemia-reperfusion injury (DIR), and diabetic but administered dexmedetomidine followed by hepatic IRI (DIRD) groups. Hepatic tissue samples were evaluated histopathologically by semiquantitative methods. Malondialdehyde (MDA), superoxide dismutase (SOD), glutathion s-transpherase (GST), and catalase (CAT) enzyme levels were investigated in liver and kidney tissues as oxidative state parameters. Results: In Group DIR; hepatocyte degeneration, sinusoidal dilatation, pycnotic nucleus, and necrotic cells were found to be more in rat hepatic tissue; while mononuclear cell infiltration was higher in the parenchyme. MDA levels were significantly lower; but SOD levels were significantly higher in Group DIRD with regard to Group DIR. In the IRI induced diabetic rats’ hepatic and nephrotic tissues MDA levels, showing oxidative injury, were found to be lower. SOD levels, showing early antioxidant activity, were higher. Conclusion: The enzymatic findings of our study together with the hepatic histopathology indicate that dexmedetomidine has a potential role to decrease IRI. Key words: Hepatic ischemia reperfusion injury; Diabetes mellitus; Dexmedetomidine; Rat; MDA; SOD Citation: Sezen SC, Işık B, Bilge M, Arslan M, Çomu FM, Öztürk L, Kesimci E, Kavutçu M. Effect of dexmedetomidine on ischemia-reperfusion injury of liver and kidney tissues in experimental diabetes and hepatic ischemia-reperfusion injury induced rats. Anaesth Pain & Intensive Care 2016;20(2):143-149 Received: 21 November 2015; Reviewed: 10, 24 December 2015, 9, 10 June 2016; Corrected: 12 December 2015; Accepted: 10 June 2016 INTRODUCTİON Perioperative acute tissue injury induced by ischemia-reperfusion is a comman clinical event caused by reduced blood supply to the tissue being compromised during major surgery. Ischemia leads to cellular injury by depleting cellular energy deposits and resulting in accumulation of toxic metabolites. The reperfusion of tissues that have remained in ischemic conditions causes even more damage.1 Furthermore hepatic ischemia-reperfusion injury (IRI) demonstrates a strong relationship with peri-operative acute kidney injury.2 The etiology of diabetic complications is strongly associated with increased oxidative stress (OS). Diabetic patients are known to have a high risk of developing OS or IRI which results with tissue failure.3 The most important role in ischemia and reperfusion is played by free oxygen radicals.1 In diabetes, characterized by hyperglycemia, even more free oxygen radicals are produced due to oxidation of glucose and glycosylation of proteins.3 The structures which are most sensitive to free oxygen radicals in the cells are membrane lipids, proteins, nucleic acids and deoxyribonucleic acids.1 It has been reported that endogenous antioxidant enzymes [superoxide dismutase (SOD), glutathion s-transpherase (GST), catalase (CAT)] play an important role to alleviate IRI.4-8 Also some pharmacological agents have certain effects on IRI.1 The anesthetic agents influence endogenous antioxidant systems and free oxygen radical formation.9-12 Dexmedetomidine is a selective α-2 adrenoceptor agonist agent. It has been described as a useful and safe adjunct in many clinical applications. It has been found that it may increase urine output by considerably redistributing cardiac output, inhibiting vasopressin secretion and maintaining renal blood flow and glomerular filtration. Previous studies demonstrated that dexmedetomidine provides protection against renal, focal cerebral, cardiac, testicular, and tourniquet-induced IRI.13-18 Arslan et al observed that dexmedetomidine protected against lipid peroxidation and cellular membrane alterations in hepatic IRI, when given before induction of ischemia.17 Si et al18 demonstrated that dexmedetomidine treatment results in a partial but significant attenuation of renal demage induced by IRI through the inactivation of JAK/STAT signaling pathway in an in vivo model. The efficacy of the dexmedetomidine for IRI in diabetic patient is not resarched yet. The purpose of this experimental study was to evaluate the biochemical and histological effects of dexmedetomidine on hepatic IRI in diabetic rat’s hepatic and renal tissue. METHODOLOGY Animals and Experimental Protocol: This study was conducted in the Physiology Laboratory of Kirikkale University upon the consent of the Experimental Animals Ethics Committee of Kirikkale University. All of the procedures were performed according to the accepted standards of the Guide for the Care and Use of Laboratory Animals. In the study, 28 male Wistar Albino rats, weighing between 250 and 300 g, raised under the same environmental conditions, were used. The rats were kept under 20-21 oC at cycles of 12-hour daylight and 12-hour darkness and had free access to food until 2 hours before the anesthesia procedure. The animals were randomly separated into four groups, each containing 7 rats. Diabetes was induced by a single intraperitoneal injection of streptozotocin (Sigma Chemical, St. Louis, MO, USA) at a dose of 65 mg/kg body weight. The blood glucose levels were measured at 72 hrs following this injection. Rats were classified as diabetic if their fasting blood glucose (FBG) levels exceeded 250 mg/dl, and only animals with FBGs of > 250 mg/dl were included in the diabetic groups (diabetes only, diabetes plus ischemia-reperfusion and diabetes plus dexmedetomidine-ischemia-reperfusion). The rats were kept alive 4 weeks after streptozotocin injection to allow development of chronic diabetes before they were exposed to ischemia-reperfusion.(19) The rats were weighed before the study. Rats were anesthetized with intraperitoneal ketamine 100 mg/kg. The chest and abdomen were shaved and each animal was fixed in a supine position on the operating table. The abdomen was cleaned with 1% polyvinyl iodine and when dry, the operating field was covered with a sterile drape and median laparotomy was performed. There were four experimental groups (Group C (sham-control; n = 7), (Group DC (diabetes-sham-control; n = 7), Group DIR (diabetes-ischemia-reperfusion; n = 7), and Group DIRD (diabetes-ischemia-reperfusion-dexmedetomidine; n = 7). Sham operation was performed on the rats in Group C and Group DC. The sham operation consisted of mobilization of the hepatic pedicle only. The rats in this group were sacrificed 90 min after the procedure. Hepatic I/R injury was induced in Groups DIR and DIRD respectively with hepatic pedicle clamping using a vascular clamp as in the previous study of Arslan et al.(17) After an ischemic period of 45 min, the vascular clamp was removed. A reperfusion period was maintained for 45 min. In Group DIRD, dexmedetomidine hydrochloride 100 μg/kg, (Precedex 100 μg/2 ml, Abbott®, Abbott Laboratory, North Chicago, Illinois, USA) was administrated via intraperitoneal route 30 minutes before surgery. All the rats were given ketamine 100 mg/kg intraperitoneally and intracardiac blood samples were obtained. Preserving the tissue integrity by avoiding trauma, liver and renal biopsy samples were obtained. Biochemical Analysis: The liver and renal tissues were first washed with cold deionized water to discard blood contamination and then homogenized in a homogenizer. Measurements on cell contest require an initial preparation of the tissues. The preparation procedure may involve grinding of the tissue in a ground glass tissue blender using a rotor driven by a simple electric motor. The homogenizer as a tissue blender similar to the typical kitchen blender is used to emulsify and pulverize the tissue (Heidolph Instruments GMBH & CO KGDiax 900 Germany®) at 1000 U for about 3 min. After centrifugation at 10,000 g for about 60 min, the upper clear layer was taken. MDA levels were determined using the method of Van Ye et al,(20) based on the reaction of MDA with thiobarbituric acid (TBA). In the TBA test reaction, MDA and TBA react in acid pH to form a pink pigment with an absorption maximum at 532 nm. Arbitrary values obtained were compared with a series of standard solutions (1,1,3,3-tetraethoxypropane). Results were expressed as nmol/mg.protein. Part of the homogenate was extracted in ethanol/chloroform mixture (5/3 v/v) to discard the lipid fraction, which caused interferences in the activity measurements of T-SOD, CAT and GST activities. After centrifugation at 10.000 x g for 60 min, the upper clear layer was removed and used for the T-SOD, CAT, GST enzyme activity measurement by methods as described by Durak et al21, Aebi22 and Habig et al23 respectively. One unit of SOD activity was defined as the enzyme protein amount causing 50% inhibition in NBTH2 reduction rate and result were expressed in U/mg protein. The CAT activity method is based on the measurement of absorbance decrease due to H2O2 consumption at 240 nm. The GST activity method is based on the measurement of absorbance changes at 340 nm due to formation of GSH-CDNB complex. Histological determinations: Semiquantitative evaluation technique used by Abdel-Wahhab et al(24) was applied for interpreting the structural changes investigated in hepatic tissues of control and research groups. According to this, (-) (negative point) represents no structural change, while (+) (one positive point) represents mild, (++) (two positive points) medium and (+++) (three positive points) represents severe structural changes. Statistical analysis: The Statistical Package for the Social Sciences (SPSS, Chicago, IL, USA) 20.0 softwre was used for the statistical analysis. Variations in oxidative state parameters, and histopathological examination between study groups were assessed using the Kruskal-Wallis test. The Bonferroni-adjusted Mann-Whitney U-test was used after significant Kruskal-Wallis to determine which groups differed from the others. Results were expressed as mean ± standard deviation (Mean ± SD). Statistical significance was set at a p value < 0.05 for all analyses. RESULTS There was statistically significant difference observed between the groups with respect to findings from the histological changes in the rat liver tissue (hepatocyte degeneration, sinüsoidal dilatation, pycnotic nucleus, prenecrotic cell) determined by light microscopy according to semiquantitative evaluation techniques (p < 0.0001). In Group DIR, hepatocyte degeneration was significantly high compared to Group C, Group DC and Group DIRD (p < 0.0001, p < 0.0001, p = 0.002, respectively), (Table 1, Figure 1-4). Similarly, sinüsoidal dilatation was significantly higher in Group DIR (p < 0.0001, p = 0.004, p = 0.015, respectively). Although, pcynotic nucleus was decreased in Group DIRD, it did not make a significant difference in comparison to Group DIR (p = 0.053), (Table 1, Figure 1-4). The prenecrotic cells were significantly increased in Group DIR, with respect to Group C, Group DC and Group DIRD (p < 0.0001, p = 0.004, p < 0.0001, respectively), (Table 1, Figure 1-4). Table 1. The comparison of histological changes in rat hepatic tissue [Mean ± SD)] p**: Statistical significance was set at a p value < 0.05 for Kruskal-Wallis test *p < 0.05: When compared with Group DIR Figure 1: Light microscopic view of hepatic tissue of Group C (control). VC: vena centralis, *: sinusoids. ®: hepatocytes, k: Kupffer cells, G: glycogen granules, mc: minimal cellular changes, Hematoxilen & Eosin x 40 Figure 2: Light-microscopic view of hepatic tissue of Group DC (diabetes mellitus control) (G: Glycogen granules increased in number, (VC: vena centralis, *:sinusoids. ®:hepatocytes, k:Kupffer cells, G: glycogen granules, mc: minimal cellular changes; Hematoxylin & Eosin x 40) Figure 3: Light-microscopic view of hepatic tissue of Group DIR (Diabetes Mellitus and ischemia-reperfusion) (VC: vena centralis, (H) degenerative and hydrophic hepatocytes, (dej) vena centralis degeneration (centrolobar injury) (*): sinusoid dilatation. (←) pycnotic and hyperchromatic nuclei, MNL: mononuclear cell infiltration, (¯) congestion, K: Kupffer cell hyperplasia, () vacuolar degeneration (Hematoxylin & Eosin x 40) Figure 4: Light-microscopic view of hepatic tissue of Group DIRD (Diabetes Mellitus and ischemia-reperfusion together with dexmedetomidine applied group) (VC: vena centralis, (MNL) mononuclear cell infiltration, (dej) hydrophilic degeneration in hepatocytes around vena centralis, (conj) congestion, G: glycogen granules, (←) pycnotic and hyperchromatic nuclei, sinusoid dilatation (*) (Hematoxylin & Eosin x 40) Besides, in liver tissue parenchyma, MN cellular infiltration was a light microscopic finding; and showed significant changes among the groups (p < 0.0001). This was significantly higher in Group DIR, compared to Group C, DC, and DIRD (p < 0.0001, p=0.007, p = 0.007, respectively), (Table 1, Figure 1-4). The enzymatic activity of MDA, SOD and GST in hepatic tissues showed significant differences among the groups [(p = 0.019), (p = 0.034). (p = 0.008) respectively]. MDA enzyme activity was significantly incresed in Group DIR, according to Group C and Group DIRD (p = 0.011, p = 0.016, respectively), (Table 2). In Group DIR SOD enzyme activity was lower with respect to Group C and Group DIRD (p = 0.010, p = 0.038, respectively), (Table 2). The GST enzyme activity was significantly higher in Group DIR, when compared to Group C, DC and DIRD (p = 0.007, p = 0.038, p = 0.039, respectively), (Table 2). Table 2. Oxidative state parameters in rat hepatic tissue [Mean ± SD] p**: Statistical significance was set at a p value < 0.05 for Kruskal-Wallis test *p < 0.05: When compared with Group DIR The enzymatic activity of MDA, SOD in renal tissues, showed significant differences among the groups [(p < 0.0001), (p = 0.008) respectively ]. MDA enzyme activity was significantly incresed in Group DIR, according to Group C and Group DIRD (p < 0.0001, p < 0.0001, respectively). Also MDA enzyme activity level was significantly increased in Group DC, in comparison to Group C and Group DIRD (p = 0.003, p = 0.001, respectively), (Table 3). In Group DIR SOD enzyme activity was lower with respect to Group C and Group DIRD (p = 0.032, p = 0.013, respectively), (Table 3). The GST enzyme activity was significantly higher in Group DIR than the other three groups, however; CAT levels were similar among the groups (Table 3). Table 3: Oxidative state parameters in rat nephrotic tissue [Mean ± SD)] p**: Statistical significance was set at a p value < 0.05 for Kruskal-Wallis test *p < 0.05: When compared with Group DIR DISCUSSION In this study, we have reported the protective effect of dexmedetomidine in experimental hepatic and renal IRI model in the rat by investigating the MDA and SOD levels biochemically. Besides, hepatic histopathological findings also supported our report. Ischemic damage may occur with trauma, hemorrhagic shock, and some surgical interventions, mainly hepatic and renal resections. Reperfusion following ischemia results in even more injury than ischemia itself. IRI is an inflammatory response accompanied by free radical formation, leucocyte migration and activation, sinusoidal endothelial cellular damage, deteoriated microcirculation and coagulation and complement system activation.1 We also detected injury in hepatic and renal tissue caused by reperfusion following ischemia in liver. Experimental and clinical evidence indicates that OS is involved in both the pathogenesis and the complications of diabetes mellitus.25,26 Diabetes mellitus is a serious risk factor for the development of renal and cardiovascular disease. It is also related to fatty changes in the liver.27 Diabetes-related organ damage seems to be the result of multiple mechanisms. Diabetes has been associated with increased free radical reactions and oxidant tissue damage in STZ-induced diabetic rats and also in patients.26Oxidative stress has been implicated in the destruction of pancreatic β-cells28 and could largely contribute to the oxidant tissue damage associated with chronic hyperglycemia.29 A number of reports have shown that antioxidants can attenuate the complications of diabetes in patients30 and in experimental models.28,31 This study demonstrated that diabetes causes a tendency to increase the IRI. There is a lot of investigations related to the pharmacological agents or food supplements applied for decreasing OS and IRI. Antioxidant agents paly an important role in IRI by effecting antioxidant system or lessening the formation of ROS. It has been reported that anesthetic agents too, are effective in oxidative stress.1 During surgical interventions, it seems rational to get benefit from anesthetic agents in prevention of OS caused by IRI instead of using other agents. It has been declared that; dexmedetomidine; as an α-2 agonist with sedative, hypnotic properties; is important in prevention of renal, focal, cerebral, cardiac, testicular and tourniquet-induced IRI.13-18 On the other hand Bostankolu et al. concluded that dexmedetomidine did not have an additional protective role for tournique induced IRI during routine general anesthesia.32 In this study; we have shown that dexmedetomidine has a reducing effect in IRI in diabetic rats. Some biochemical tests and histopathological evaluations are applied for bringing up oxidative stress and IRI in the tissues. Reactive oxygen species (ROS) that appear with reperfusion injury damage cellular structures through the process of the lipid peroxidation of cellular membranes and yield toxic metabolites such as MDA.33 As an important intermidiate product in lipid peroxidation, MDA is used as a sensitive marker of IRI.34 ROS-induced tissue injury is triggered by various defense mechanisms.35 The first defence mechanisms include the antioxidant enzymes of SOD, CAT, and GPx. These endogenous antioxidants are the first lines of defence against oxidative stres and act by scavenging potentially damaging free radical moieties.36 There is a balance between ROS and the scavenging capacity of antioxidant enzymes.1-8 In this study, for evaluation of oxidative damage and antioxidant activity, MDS, SOD, GST and CAT levels were determined in liver and kidney tissues. MDA levels in hepatic and renal tissues were higher in Group DIR compared to Group C and Group DIRD. GST levels were higher in Group DIR compared to all the other three groups. When the groups were arranged from highest to lowest order, with respect to CAT levels, the order was; Group DIR, Group DIRD, Group DC and Group C. However, the difference was not significant. The acute phase reactant MDA, as a marker of OS, was found to be high in Group DIR and low in Group DIRD. This could be interpreted as the presence of protective effect of dexmedetomidine in IRI. IRI developing in splanchnic area causes injury also in the other organs.35 Leithead et al showed that clinically significant hepatic IRI demonstrates a strong relationship with peri-operative acute kidney injury.2 In our experimental research that showed correlation to that of research by Leithead et al. After hepatic IRI in diabetic rats renal OS marker MDA levels were significantly more in Group DIR than Group DIRD. In our study, we observed histopathological changes in the ischemic liver tissue and alterations in the level of MDA, SOD, GST and CAT levels which are OS markers. Histopathological changes of the liver tissues are hepatocyt degeneration, sinusoidal dilatation, nuclear picnosis, celluler necrosis, mononuclear cell infiltrationat paranchimal tissue. These histopathological injury scores were significantly lower in the Group DIRD than those in group DIR. LIMITATION Study limitation is there was no negative control group, as this type of surgical intervention is not possible in rats without anesthesia. CONCLUSION The enzymatic findings of our study together with the hepatic histopathology indicate that dexmedetomidine has a potential role to decrease ischemia-reperfusion injury. Conflict of interest and funding: The authors have not received any funding or benefits from industry or elsewhere to conduct this study. Author contribution: ŞCS: Concept, conduction of the study work and manuscript editing; BI: the main author to write the article; MB & MK: biochemical analysis; MA: manuscript writing; FMÇ: helped us with experimental study; LÖ & EK: collection of data REFERENCES Collard CD, Gelman S. Pathophysiology, clinical manifestations, and prevention of ischemia-reperfusion injury. Anesthesiology. 2001;94(6):1133. [PubMed] [Free full text] Leithead JA, Armstrong MJ, Corbett C, Andrew M, Kothari C, Gunson BK, et al. Hepatic ischemia reperfusion injury is associated with acute kidney injury following donation after brain death liver transplantation. Transpl Int. 2013;26(11):1116. doi: 10.1111/tri.12175. [PubMed] [Free full text] Panés J, Kurose I, Rodriguez-Vaca D, Anderson DC, Miyasaka M, Tso P, et al. Diabetes exacerbates inflammatory responses to ischemia-reperfusion. Circulation. 1996;93(1):161. [PubMed] [Free full text] Touyz RM. Reactive oxygen species and angiotensin II signaling in vascular cells-implications in cardiovascular disease. Braz J Med Biol Res. 2004;37:1263. [PubMed] [Free full text] Olivares-Corichi IM, Ceballos G, Ortega-Camarillo C, Guzman-Grenfell AM, Hicks JJ. Reactive oxygen species (ROS) induce chemical and structural changes on human insulin in vitro, including alterations in its immunoreactivity. Front Biosci. 2005;10:834. [PubMed] Witko-Sarsat V, Friedlander M, Capeillere-Blandin C, Nguyen-Khoa T, Nguyen AT, Zingraff J, et al. Advanced oxidation protein products as a novel marker of oxidative stress in uremia. Kidney Int. 1996;49:1304. [PubMed] Harman D. Free radical theory of aging: An update: Increasing the functional life span. Ann N Y Acad Sci. 2006;1067:10. [PubMed] Nita DA, Nita V, Spulber S, Moldovan M, Popa DP, Zagrean AM, Zagrean L. Oxidative damage following cerebral ischemia depends on reperfusion – a biochemical study in rat. J Cell Mol Med. 2001;5:163–170. [PubMed] [Free full text] Annecke T, Kubitz JC, Kahr S, Hilberath JM, Langer K, Kemming GI, et al. Effects of sevoflurane and propofol on ischaemia-reperfusion injury after thoracic-aortic occlusion in pigs. Br J Anaesth. 2007;98(5):581. [PubMed] [Free full text] De Hert SG, Van der Linden PJ, Cromheecke S, Meeus R, Nelis A, Van Reeth V, ten Broecke PW, et al. Cardioprotective properties of sevoflurane in patients undergoing coronary surgery with cardiopulmonary bypass are related to the modalities of its administration. Anesthesiology. 2004;101(2):299. [PubMed] [Free full text] Yuzer H, Yuzbasioglu MF, Ciralik H, Kurutas EB, Ozkan OV, Bulbuloglu E, et al. Effects of intravenous anesthetics on renal ischemia/reperfusion injury. Ren Fail. 2009;31(4):290. [PubMed] [Free full text] Lee HT, Ota-Setlik A, Fu Y, Nasr SH, Emala CW. Differential protective effects of volatile anesthetics against renal ischemia-reperfusion injury in vivo. Anesthesiology. 2004;101(6):1313. [PubMed] [Free full text] Lai YC, Tsai PS, Huang CJ. Effects of dexmedetomidine on regulating endotoxin-induced up-regulation of inflammatory molecules in murine macrophages. J Surg Res. 2009;154(2):212. doi: 10.1016/j.jss.2008.07.010. [PubMed] Yoshitomi O, Cho S, Hara T, Shibata I, Maekawa T, Ureshino H, Sumikawa K. Direct protective effects of dexmedetomidine against myocardial ischemia-reperfusion injury in anesthetized pigs. Shock. 2012;38(1):92. doi: 10.1097/SHK.0b013e318254d3fb. [PubMed] Jolkkonen J, Puurunen K, Koistinaho J, Kauppinen R, Haapalinna A, Nieminen L, et al. Neuroprotection by the alpha2-adrenoceptor agonist, dexmedetomidine, in rat focal cerebral ischemia. Eur J Pharmacol. 1999;372(1):31. [PubMed] Kocoglu H, Ozturk H, Ozturk H, Yilmaz F, Gulcu N. Effect of dexmedetomidine on ischemia-reperfusion injury in rat kidney: a histopathologic study. Ren Fail. 2009;31(1):70. doi: 10.1080/08860220802546487. [PubMed] Arslan M, Çomu FM, Küçük A, Öztürk L, Yaylak F. Dexmedetomidine protects against lipid peroxidation and erythrocyte deformability alterations in experimental hepatic ischemia reperfusion injury. Libyan J Med. 2012;7. doi: 10.3402/ljm.v7i0.18185 [PubMed] [Free full text] Si Y, Bao H, Han L, Shi H, Zhang Y, Xu L, et al. Dexmedetomidine protects against renal ischemia and reperfusion injury by inhibiting the JAK/STAT signaling activation. J Transl Med. 2013;11(1):141. doi: 10.1186/1479-5876-11-141. [PubMed][Free full text] Türeci E, İş M, Üzüm G, Akyüz F, Ulu MO, Döşoğlu M, et al. Alterations in blood-brain barrier after traumatic brain injury in streptozotocin-induced diabetic rats. J Nervous Sys Surgery 2009;2(2):79. [Free full text] Van Ye TM, Roza AM, Pieper GM, Henderson J Jr, Johnson JP, Adams MB. Inhibition of intestinal lipid peroxidation does not minimize morphological damage. J Surg Res 1993;55:553. [PubMed] Durak I, Canbolat O, Kavutcu M, Öztürk HS, Yurtarslanı Z. Activities of total, cytoplasmic and mihochondrial superoxide dismutase enzymes in sera and pleural fluids from patient with lung cancer. J Clin Lab Anal 1996;10:17. [PubMed] Aebi H. Catalase. In: H.U.Bergmeyer (Ed): Methods of Enzymatic Analysis, Academic Press , New York and London, 1974;pp.673-677. Habig WH, Pabst MJ, Jakoby WB. Glutathione S-transferases. The first enzymatic step in mercapturic acid formation. J Biol Chem 1974;249:7130. [PubMed] [Free full text] Abdel-Wahhab MA, Nada SA, Arbid MS. Ochratoxicosis: Prevention of developmental toxicity by L-methionine in rats. J Appl Toxicol 1999;19:7. [PubMed] Wolff SP. Diabetes mellitus and free radicals: free radicals, transition metals and oxidative stress in the aetiology of diabetes mellitus and complications. Br Med Bull. 1993;49:642. [PubMed] [Free full text] West IC. Radicals and oxidative stress in diabetes. Diabet Med. 2000;17:171–180. [PubMed] Wanless IR, Lentz JS. Fatty liver hepatitis (steatohepatitis) and obesity: an autopsy study with analysis risk factors. Hepatology. 1990;12:1106. [PubMed] Hotta M, Tashiro F, Ikegami H, Niwa H, Ogihara T, Yodoi J, Miyazaki J. Pancreatic cell-specific expression of thioredoxin, an antioxidative and antiapoptotic protein, prevents autoimmune and streptozotocin-induced diabetes. J Exp Med. 1998;188:1445. [PubMed] [Free full text] Baynes JW. Role of oxidative stress in the development of complications in diabetes. Diabetes. 1991;40:405. [PubMed] Borcea V, Nourooz-Zadeh J, Wolff SP, Klevesath M, Hofmann M, Urich H, et al. α-Lipoic acid decreases oxidative stress even in diabetic patients with poor glycemic control and albuminuria. Free Radic Biol Med. 1999;26:1495. [PubMed] Fitzl G, Martin R, Dettmer D, Hermsdorf V, Drews H, Welt K. Protective effect of ginkgo biloba extract EGb 761 on myocardium of experimentally diabetic rats, I: ultrastructural and biochemical investigation on cardiomyocytes. Exp Toxicol Pathol. 1999;51:189. [PubMed] Bostankolu E, Ayoglu H, Yurtlu S, Okyay RD, Erdogan G, Deniz Y, et al. Dexmedetomidine did not reduce the effects of tourniquet-induced ischemia-reperfusion injury during general anesthesia. Kaohsiung J Med Sci. 2013;29(2):75. doi: 10.1016/j.kjms.2012.08.013. [PubMed] [Free full text] Wakai A, Wang JH, Winter DC, Street JT, O’Sullivan RG, Redmond HP. Tourniquet-induced systemic inflammatory response in extremity surgery. J Trauma 2001;51:922. [PubMed] Concannon MJ, Kester CG, Welsh CF, Puckett CL. Patterns of free-radical production after tourniquet ischemia implications for the hand surgeon. Plast Reconstr Surg 1992;89:846. [PubMed] Grisham MB, Granger DN. Free radicals: reactive metabolites of oxygen as mediators of postischemic reperfusion injury. In: Martson A, Bulkley GB, Fiddian-Green RG, Haglund U, editors. Splanchnic İschemia and Multiple Organ Failure. St Louis, MO: Mosby;1989. pp. 135–144. Mccard JM. The evolution of free radicals and oxidative stress. Am J Med 2000;108:652. [PubMed]
... These previous reports indicate that diabetic microenvironment may enhance NF-κB activity and synthesis of MMPs, which alter the biomechanical characteristics of ECM. Of note, MMPs are a family of ECM-degrading enzymes, which catalyse both collagen and proteoglycan degradation including collagenases (MMP-1 and 13), the expression of which are enhanced in high glucose concentration [52,53]. MMP-13 has been reported as a highly expressed proteinase in OA, which can degrade both type II collagen and aggrecan [54]. ...
Diabetes mellitus (DM) is well-known to exert complications such as retinopathy, cardiomyopathy and neuropathy. However, in recent years, an elevated osteoarthritis (OA) complaints among diabetics have been observed, portending the risk of diabetic OA. Since formation of advanced glycation end products (AGE) is believed to be the etiology of various diseases under hyperglycemic conditions, we firstly established that streptozotocin-induced DM could potentiate the development of OA in C57BL/6J mouse model, and further explored the intra-articularly administered adipose-derived stem cell (ADSC) therapy focusing on underlying AGE-associated mechanism. Our results demonstrated that hyperglycemic mice exhibited OA-like structural impairments including a proteoglycan loss and articular cartilage fibrillations in knee joint. Highly expressed levels of carboxymethyl lysine (CML), an AGE and their receptors (RAGE), which are hallmarks of hyperglycemic microenvironment were manifested. The elevated oxidative stress in diabetic OA knee-joint was revealed through increased levels of malondialdehyde (MDA). Further, oxidative stress-activated nuclear factor kappa B (NF-κB), the marker of proinflammatory signalling pathway was also accrued; and levels of matrix metalloproteinase-1 and 13 were upregulated. However, ADSC treatment attenuated all OA-like changes by 4 weeks, and dampened levels of CML, RAGE, MDA, NF-κB, MMP-1 and 13. These results suggest that during repair and regeneration, ADSCs inhibited glycation-mediated inflammatory cascade and rejuvenated cartilaginous tissue, thereby promoting knee-joint integrity in diabetic milieu.
... Studies from rat hind-limb ischemia models suggest that in diabetic conditions, MMP activity is inhibited and thus angiogenesis is prevented. 6 The aim of this research is to qualify Black tea as reducer of Diabetic Cardiac Complications. Flavonoids (polyphenols) are present as major constituents in all form of the Tea. ...
... As expected, the levels of inflammatory cytokines, and consequently those of MMP-12, were significantly higher in T2DM patients that showed more prominent impairment of CV structure and function than nonT2DM subjects. Therefore, targeting inflammatory and MMPs' pathways could be a part of the strategy to prevent and control diabetesrelated CV complications [11,50]. ...
Abstract Background The relationship between dyslipidemia, inflammation and CV organ damage in type 2 diabetes mellitus (T2DM) is complex. Insulin resistance and inflammatory cytokines interleukins (ILs) increase plasma triglycerides (TG). ILs also up-regulate expression of matrix-metalloproteinases (MMPs) that, together with TG, decrease high density lipoprotein cholesterol (HDL) levels. High TG, low HDL, increased ILs and MMPs trigger structural and functional changes in different parts of cardiovascular (CV) system. To understand better the role of lipids and inflammation in CV organ damage, the present study investigated the inter-relationships between lipids, ILs and MMPs, as well as the associations of lipids, ILs and MMPs with various CV measures, both in diabetic and non-diabetic population (nonT2DM). Methods In T2DM patients (N = 191) and nonT2DM subjects (N = 94) were assessed carotid intima-media thickness (cIMT) and inter-adventitial diameter (IADiam), carotid wave speed (ccaWS), carotid-femoral pulse wave velocity (cfPWV), left ventricular (LV) mass, LV systolic (s′) and early diastolic (e′) longitudinal velocities of mitral annulus, together with glycemic control, lipid profile, IL-6, IL-18 and MMP-12. Results T2DM patients, as compared to nonT2DM subjects, had significantly higher plasma levels of IL-6, IL-18, MMP-12 and lower HDL (P
... Growing evidences support the protective role of TIMPs as inhibitors of MMP-2 and MMP-9 against cardiovascular diseases (34,35). TIMP-1 as an inhibitor of a wide range of MMPs are inversely associated with plaque atherosclerosis instability and its poor prognosis of cardiovascular disease (36). ...
Background. Myocardial fibrosis is identified as a major side effect of Diabetes Mellitus on the heart. Some bio-markers including the ratio of matrix metalloproteinases and their inhibitors in collagen synthesis and collagen degradation are clinically useful in the diagnosis and identification of myocardial fibrosis. In addition, regular aerobic exercise training is one of the major and non-pharmacological solutions for preserving and promoting cardiovascular health.
Objectives. Thus, the current research aims at investigating the effect of aerobic training on levels of matrix metalloproteinase-9 (MMP-9) and tissue inhibitor of matrix metalloproteinase 1 (TIMP1) in diabetic rats.
Methods. 30 male Wistar rats were randomly divided into 3 groups (healthy control, diabetic control, and exercise diabetic). Diabetes was induced by intraperitoneal injection of streptozotocin at 55 mg/kg per body weight. The exercise program comprised eight weeks of running on a bar for 60 minutes at a speed of 25 m/min. Biopsy was carried out 48 h after the last exercise session, and cardiac levels of MMP-9 and TIMP-1 values were measured by the ELISA sandwich method.
Results. The findings of the current research indicated that diabetes induction caused significant increase in cardiac levels of MMP-9 and significant reduction of TIMP-1 compared to the healthy group. In addition, it was revealed that the implementation of 8 weeks-aerobic exercise significantly reduced cardiac levels of MMP-9 and significantly increased TIMP-1 compared to the group without exercise.
Conclusions. The execution of aerobic training in diabetic rats inhibited progressive factors of myocardial fibrosis and thus fibrosis risk in diabetic heart is highly reduced.
... A growing body of evidence supports the involvement of dysregulated MMPs in cardiovascular diseases (CVDs) including atherosclerosis, aneurysms, and hypertension. Atherosclerotic plaques showed increased expression of MMP-1, MMP-2, and MMP-9 as well as a disturbed ratio of MMPs and tissue inhibitors of metalloproteinase (TIMPs) (3,23). Patients with acute myocardial infarction, unstable angina, and hypertension exhibited higher levels of circulating MMPs such as MMP-2 and MMP-9 relative to healthy individuals (11,22). ...
The glycocalyx is crucial for normal endothelial function. It also tethers extracellular superoxide dismutase (SOD3), which protects the endothelium against oxidative damage. Proteolytic enzymes [matrix metalloproteinases (MMPs)] are capable of disrupting endothelial cell surface proteins, such as syndecans, resulting in derangements of the endothelial glycocalyx. We sought to test the role of MMPs in oxidative stress-mediated disruption of the endothelial glycocalyx and examine the effect of pharmacological inhibition of MMPs on mitigating this detrimental effect. We also examined the role of histone deacetylase (HDAC) in the oxidative stress-mediated MMP induction and glycocalyx remodeling. Oxidative stress was experimentally induced in human adipose microvascular endothelial cells using H 2 O 2 and buthionine sulfoximine in the presence and absence of potent MMP and HDAC inhibitors. H 2 O 2 and buthionine sulfoximine resulted in a notable loss of the endothelial glycocalyx; they also increased the expression and proteolytic activity of MMP-2 and MMP-9 and subsequently increased the shedding of syndecan-1 and SOD3 from the endothelial cell surface. MMP upregulation was accompanied by a decline in mRNA and protein levels of their inhibitors, tissue inhibitors of metalloproteinase (TIMPs; TIMP-1 and TIMP-3). Furthermore, oxidative stress induced HDAC activity. Inhibition of MMPs and HDAC reversed syndecan-1 and SOD3 shedding and maintained endothelial glycocalyx integrity. HDAC inhibition increased TIMP expression and reduced MMP expression and activity in endothelial cells. Our findings shed light on MMPs and HDAC as therapeutically targetable mechanisms in oxidative stress-induced glycocalyx remodeling.
... 15 Clinically, matrix metalloproteinases (MMPs) have been shown to be overexpressed in subjects with DM, resulting in a compromised ECM. [16][17][18][19] During the repair phase of diabetic tendon healing, production of collagen I, collagen III, and glycosaminoglycans are decreased. 20,21 Changes to the levels of growth factors, reduced cellular proliferation, decreased angiogenesis, and a compromised ECM are some of the contributing factors resulting in compromised tendon healing in patients with diabetes. ...
Introduction:
Healing of tendon injuries is often plagued by significant scar formation and compromised biomechanical function. For those with diabetes, these injuries are further complicated by alterations to the extracellular matrix of the tendon, poor circulation, and delayed wound healing; consequently, complications and re-rupture rates for patients with diabetes are reported higher than the typical patient population. Placental derived membranes, specifically dehydrated human amnion/chorion membranes (dACMs), have been utilized clinically as an adhesion barrier, and these membranes have been shown to reduce scarring and aid in tissue repair.
Objective:
The purpose of this study was to evaluate the effect of dACMs on tendon repair in a diabetic model with impaired healing.
Materials and methods:
Using a type II diabetic model (BBZDR/WOR rats), a full-thickness injury was made through the Achilles tendon and repaired using a modified Kessler method. Repaired tendons were wrapped with dACM or left unwrapped as a control (n = 15/group; n = 30 total). Tendons were retrieved at 14 (n = 5/group; n = 10 total) or 28 days (n = 10/group; n = 20 total) and evaluated using histology, immunofluorescence, and biomechanical testing.
Results:
Treatment of tendons with dACM resulted in reduced failure rates, increased cell migration, and improved mechanical properties (compared with unwrapped controls). The dACM-treated tendons also showed changes in the production of several important biomarkers to tendon healing at both 14 and 28 days; most notably, Scleraxis was found to be upregulated in dACM-treated tendons.
Conclusions:
This study highlights a promising treatment option for this challenging clinical population.
... These previous reports indicate that diabetic microenvironment may enhance NF-κB activity and synthesis of MMPs, which alter the biomechanical characteristics of ECM. Of note, MMPs are a family of ECM-degrading enzymes, which catalyse both collagen and proteoglycan degradation including collagenases (MMP-1 and 13), the expression of which are enhanced in high glucose concentration [52,53]. MMP-13 has been reported as a highly expressed proteinase in OA, which can degrade both type II collagen and aggrecan [54]. ...
Diabetes mellitus (DM) is well-known to exert complications such as retinopathy, cardiomyopathy and neuropathy. However, in recent years, an elevated osteoarthritis (OA) complaints among diabetics have been observed, portending the risk of diabetic OA. Since formation of advanced glycation end products (AGE) is believed to be the etiology of various diseases under hyperglycemic conditions, we firstly established that streptozotocin-induced DM could potentiate the development of OA in C57BL/6J mouse model, and further explored the intra-articularly administered adipose-derived stem cell (ADSC) therapy focusing on underlying AGE-associated mechanism. Our results demonstrated that hyperglycemic mice exhibited OA-like structural impairments including a proteoglycan loss and articular cartilage fibrillations in knee joint. Highly expressed levels of carboxymethyl lysine (CML), an AGE and their receptors (RAGE), which are hallmarks of hyperglycemic microenvironment were manifested. The elevated oxidative stress in diabetic OA knee-joint was revealed through increased levels of malondialdehyde (MDA). Further, oxidative stress-activated nuclear factor kappa B (NF-κB), the marker of proinflammatory signalling pathway was also accrued; and levels of matrix metalloproteinase-1 and 13 were upregulated. However, ADSC treatment attenuated all OA-like changes by 4 weeks, and dampened levels of CML, RAGE, MDA, NF-κB, MMP-1 and 13. These results suggest that during repair and regeneration, ADSCs inhibited glycation-mediated inflammatory cascade and rejuvenated cartilaginous tissue, thereby promoting knee-joint integrity in diabetic milieu.
... As a result, it was obtained that at high glucose concentrations collagen degradation is induced by overproduction of MMPs, which leads to a vulnerable tissue [68]. Adding the MMPs also to the process of generation of diabetic fibrosis, this being a pathology differentiated by the excess of MMPs in the ECM generating changes in the same. ...
High blood glucose levels are a hallmark of the metabolic syndrome known as diabetes mellitus. More than 600 million people will have diabetes by 2045 as the global prevalence of the disease continues to rise. Contemporary antidiabetic drugs reduce hyperglycemia and its consequences. However, these drugs come with undesirable side effects, so it's encouraging that research into plant extracts and bioactive substances with antidiabetic characteristics is on the rise. Natural remedies are preferable to conventional anti-diabetic drugs since they are safer for the body, more affordable and have fewer potential adverse effects. Biological macromolecules such as liposomes, niosomes, polymeric nanoparticles, solid lipid nanoparticles, nanoemulsions and metallic nanoparticles are explored in this review. Current drug restrictions have been addressed, and the effectiveness of plant-based antidiabetic therapies has enhanced the merits of these methods. Plant extracts' loading capacity and the carriers' stability are the primary obstacles in developing plant-based nanocarriers. Hydrophilic, hydrophobic, and amphiphilic drugs are covered, and a brief overview of the amphipathic features of liposomes, phospholipids, and lipid nanocarriers is provided. Metallic nanoparticles' benefits and attendant risks are highlighted to emphasize their efficiency in treating hyperglycemia. Researchers interested in the potential of nanoparticles loaded with plant extracts as antidiabetic therapeutics may find the current helpful review.
Aim: Complementary effects of dabigatran etexilate (DE), exercise training (ET) and combination (DE+ET) on the development and composition of the atherosclerotic lesions in diabetic apoE knockout (apoE-/-) mice. Methods: In 48 male apoE-/- diabetic mice, streptozotocin (STZ) was induced for 5 consecutive days. Mice received figh-fat diet (HFD) for 8 weeks and were randomized into 4 groups (1.Control/CG, 2.DEG: HFD with DE, 3.ETG: ET on treadmill, 4.DE+ETG: Combination DE and ET treatment). At the end of 8th week, all mice were euthanatized and morphometry of the aortic lesions at the level of aortic valve was obtained. Collagen, elastin, TNF-a, MCP-1, matrix-metalloproteinases (MMP-2,-3,-9), and TIMP-1 concentration within plaques at aortic valve were determined. Results: All active groups had significantly smaller aorta stenosis (DEG:7.9±2.2%, ETG:17.3±5.3%, DE+ETG:7.1±2.7%) compared to CG (23.3±5.5% p<0.05), reduced the relative intra-plaque concentrations of macrophages, MCP-1, MMP-3 and MMP-9, and considerably increased collagen, elastin and TIMP-1 (p<0.05). Group 4 showed the most pronounced results (p<0.05). Both DEG and DE+ETG significantly reduced MMP-2 and TNF-a concentrations compared to ETG and CG (p<0.010). Conclusion: DE and ET treatment in diabetic apoE-/- mice showed complementary amelioration of atherosclerotic lesions development and stability, mediated by the anti-inflammatory modulation of both DE and ET.
Aims:
The aim of this study was to investigate the effects of pioglitazone on reactive oxygen species (ROS), expressions/activities of MMPs and TIMP-2, and VSMC proliferation and vascular reactivity in high glucose (HG)-induced human saphenous vein (HSV) grafts.
Methods:
HSV grafts (n = 10) obtained from patients undergoing CABG were incubated with 30 mM glucose and/or 10 μM pioglitazone or 0.1 % DMSO for 24 h after endothelium removal. ROS levels were examined by chemiluminescence assay, MMP-2,-9,-14, TIMP-2, and α-SMA expression/activity was determined by gelatine zymography/immunohistochemistry. Vascular reactivity to potassium chloride, noradrenaline, serotonin, prostaglandin F2α and papaverine was assessed in HSVs.
Results:
HG induced superoxide anion (SA) (123 %) and other ROS levels (159 %), up-regulated MMP-2 expression (180 %)/activity (79 %), MMP-14 expression (24 %) and MMP-9 activity while down-regulating TIMP-2 expression (27 %). HG elevated total MMP-2/TIMP-2 ratio (483 %) and MMP-14/TIMP-2 ratio (78 %). However, HG plus pioglitazone inhibited SA (30 %) and other ROS levels (29 %), down-regulated MMP-2 expression (76 %)/activity (83 %), MMP-14 expression (38 %) and MMP-9 activity, while reversing TIMP-2 expression (44 %). HG plus pioglitazone decreased total MMP-2/TIMP-2 ratio (91 %) and MMP-14/TIMP-2 ratio (59 %). HG impaired contractions to all agents but pioglitazone improved them.
Conclusions:
Pioglitazone may contribute to the prevention of restenosis and maintaining vascular function in HSV grafts of DM patients undergoing CABG.
Diabetes is a chronic disease state in which the pancreas fails to secrete sufficient insulin, resulting in elevation of the blood glucose levels. As one of the most prevalent diseases worldwide, diabetes is recognized as a global health concern that, if undiagnosed or untreated, can lead to serious and life-threatening complications, such as kidney failure, cardiovascular disease and diabetic retinopathy. Despite progress in the diagnosis of diabetes, limitations still exist with current analytical techniques and, therefore, the development of precise sensing devices for on-site, real-time detection of diabetes is needed. Biosensors have contributed significantly in the field of the diabetes healthcare, due to their cost-effectiveness, portability, ease of use, and rapid assay time. Recently, there has developed a preference for the utilization of aptamers over antibodies in designing biosensors. Aptasensors, biosensors made with aptamers, offer potential in the diagnosis of diabetes. Aptamers, due to having lower molecular weight, low price, and stability over a wide temperature range and pH range, their in vitro synthesis, and the ability to refold after being removed from denaturing conditions compared to antibodies, have some distinctive characteristics as well as diverse types, such as optical FNA-based biosensors, colorimetric biosensors, fluorescent biosensors and electrochemical FNA-based biosensors. With this in mind, we highlight the recent developments and novel perspectives in the field of aptasensor design to quantitatively monitor diabetes biomarkers. Finally, some results are highlighted to offer a basis for future design of aptasensor kits for diabetes diagnosis.
Aims
Few studies investigated the association of genetic difference in metalloproteinase-2 (MMP-2) gene with diabetic retinopathy but with mixed outcome. To investigate the association between a set of MMP-2 genetic variants and the risk of diabetic retinopathy (DR) in Tunisian population with type 2 diabetes.
Subjects and methods
A retrospective case-control study comprising a total of 779 type 2 diabetes patients with or without diabetic retinopathy was conducted. Genotyping was prepared by TaqMan® SNP genotyping qRT-PCR. The variants used were rs243865 (C/T), rs243864 (T/G), rs243866 (G/T) and rs2285053 (C/T).
Results
The minor allele frequency (MAF) of the rs243864 MMP-2 variant was significantly higher among diabetic retinopathy patients. Setting homozygous wild type genotype carrier as reference, the rs243864T/G allele was associated with increased risk of diabetic retinopathy under the dominant, recessive, and additive models which persisted when key covariates were controlled for, while a reduced risk of diabetic retinopathy progression was seen after adjustment between non-proliferative and proliferative diabetic patients. Furthermore, the heterozygous genotype GT of the rs243866 variant is positively associated with the risk of proliferative diabetic retinopathy in the additive model. A limited linkage disequilibrium (LD) was revealed between the four-matrix metalloproteinase-2 variants. Four-loci haplotype analysis identified, GCTC, TTTC, and GCTT haplotypes to be positively associated with the risk of diabetic retinopathy.
Conclusion
Our findings demonstrate that the MMP-2 variant rs243864 and 243,866 are related to the susceptibility to diabetic retinopathy and the progression of the disease in Tunisian population with type 2 diabetes.
Aim/hypothesis The aim of our study was to characterize the human salivary proteome and determine the changes in protein expression in 2 different stages of diabetic retinopathy with type-2 diabetes mellitus: (1) with non-proliferative diabetic retinopathy (NPDR) and (2) with proliferative diabetic retinopathy (PDR). Type-2 diabetes without diabetic retinopathy (XDR) was designated as control. Method In this study, 45 saliva samples were collected (15 samples from XDR control group, 15 samples from NPDR disease group and 15 samples from PDR disease group). Salivary proteins were extracted, reduced, alkylated, trypsin digested and labeled with iTRAQ before analyzing by Orbitrap fusion tribrid mass spectrometer. Proteins annotation, fold change calculation and statistical analysis were interrogated by Proteome Discoverer. Biological pathway analysis was performed by Ingenuity Pathway Analysis. Data are available via ProteomeXchange with identifiers PXD003723-PX003725. Results A total of 315 proteins were identified from the salivary proteome and 119 proteins were found to be differentially expressed. The differentially expressed proteins from the NPDR disease group and the PDR disease group were assigned to respective canonical pathways indicating increased LXR/RXR activation, FXR/RXR activation, acute phase response signaling, sucrose degradation V and regulation of actin-based motility by Rho in the PDR disease group compared to the NPDR disease group Conclusions/Interpretation Progression from non-proliferative to proliferative retinopathy in type-2 diabetic patients is a complex multi-mechanism and systemic process. Furthermore, saliva was shown to be a feasible alternative sample source for diabetic retinopathy biomarkers.
Aim/hypothesis The aim of our study was to characterize the human salivary proteome and determine the changes in protein expression in 2 different stages of diabetic retinopathy with type-2 diabetes mellitus: (1) with non-proliferative diabetic retinopathy (NPDR) and (2) with proliferative diabetic retinopathy (PDR). Type-2 diabetes without diabetic retinopathy (XDR) was designated as control. Method In this study, 45 saliva samples were collected (15 samples from XDR control group, 15 samples from NPDR disease group and 15 samples from PDR disease group). Salivary proteins were extracted, reduced, alkylated, trypsin digested and labeled with iTRAQ before analyzing by Orbitrap fusion tribrid mass spectrometer. Proteins annotation, fold change calculation and statistical analysis were interrogated by Proteome Discoverer. Biological pathway analysis was performed by Ingenuity Pathway Analysis. Data are available via ProteomeXchange with identifiers PXD003723-PX003725. Results A total of 315 proteins were identified from the salivary proteome and 119 proteins were found to be differentially expressed. The differentially expressed proteins from the NPDR disease group and the PDR disease group were assigned to respective canonical pathways indicating increased LXR/RXR activation, FXR/RXR activation, acute phase response signaling, sucrose degradation V and regulation of actin-based motility by Rho in the PDR disease group compared to the NPDR disease group Conclusions/Interpretation Progression from non-proliferative to proliferative retinopathy in type-2 diabetic patients is a complex multi-mechanism and systemic process. Furthermore, saliva was shown to be a feasible alternative sample source for diabetic retinopathy biomarkers.
Hyperglycemia caused by diabetes mellitus, in sensitive tissues such as the kidney, can cause dysfunction by damaging the blood vessels. Matrix metalloproteinases (MMPs), especially MMP-2 and MMP-9, play a significant role in the degradation of proteins and angiogenesis; while epidermal growth factor receptor (EGFR) is involved in the recovery of damaged tissues. Herein, we investigated the relationship between MMP-2 and MMP-9 / EGFR in the kidney tissues of streptozotocin-induced Wistar male rats. We also examined the effects of resveratrol known as a strong tissue-protective on these changes. Diabetes was induced by streptozotocin (55 mg/kg) and trans-resveratrol (20 mg/kg/day intraperitoneal) was used for treatment. Rats were divided into 4 groups as control, resveratrol (Res), diabetes (Diab) and diabetes plus resveratrol (Diab+Res). Superoxide dismutase (SOD) and catalase (CAT) levels were significantly decreased in the kidneys in the diabetic group, whereas nitrite / nitrate, urea, creatine kinase (CK) and uric acid concentrations increased. MMP-2, MMP-9, calcium-binding protein B (S100B) and platelet-derived growth factor (PDGF) concentrations of kidney were increased although reduced EGFR in the diabetes group. Resveratrol supplementation markedly restored all these structures. Diabetes activates MMP related inflammation and oxidative stress by suppressing antioxidant enzymes in the kidney tissues. Resveratrol has partly modulatory effects on diabetes-induced changes.
Diabetes mellitus is a serious debilitating epidemic affecting all social strata, imposing huge health, social and economic burdens. Diabetic neuropathic pain, an important microvascular complication of diabetes mellitus, characterized by allodynia and hyperalgesia, is recognized as one of the most difficult types of pain to treat. The development of tolerance, inadequate relief and potential toxicity of classical antinociceptives warrant the investigation of newer agents to relieve this pain. Reactive oxygen/nitrogen species, cytokines and matrix metalloproteinases (MMPs) are implicated in the pathogenesis of diabetic neuropathy. The present study was designed to explore the effect of naringenin, a citrus flavonoid, on streptozotocin induced diabetic neuropathic pain in Wistar rats. After 8 weeks of diabetes induction, rats developed neuropathy which was evident from marked hyperalgesia and allodynia associated with enhanced oxidative-nitrosative stress, release of inflammatory mediators (TNF-α, TGF-1β), MMP-9 activation and decreased motor nerve conduction velocity. Treatment with naringenin (25, 50, 100 mg kg⁻¹) for 4 weeks starting from the 5th week of streptozotocin injection significantly attenuated behavioral, biochemical and molecular changes, along with alterations in motor nerve conduction velocity in a dose-dependent manner. Moreover, diabetic rats treated with insulin-naringenin combination produced a more pronounced effect as compared to individual drugs. The major finding of the study is that insulin alone corrected the hyperglycemia and partially reversed the pain response in diabetic rats. However, combination with naringenin not only attenuated the diabetic condition but also reversed neuropathic pain through modulation of oxidative–nitrosative stress, inflammatory cytokine release and MMP inhibition in the diabetic rats. Modulation of MMP-9 by a natural flavonoid like naringenin seems to be a novel approach to target diabetic neuropathic pain.
Diabetes mellitus is one of the largest global health emergencies threating public health worldwide. Chronic elevation of blood glucose level can lead to injury of blood vessels resulting in chronic diabetic complication, that is, diabetic vasculopathy. With respect to this vascular dysfunction in brain vasculature, diabetes mellitus confers an increased risk of ischemic stroke. Strokes in patients with diabetes are usually associated with a worse outcome. The cerebrovascular protection is not only limited to prevention of diabetes but also diabetes-induced detrimental changes in vascular structure and function before the occurrence of stroke. Effective and acute prevention of vascular dysfunction and blood–brain barrier disruption following acute ischemic stroke is important in diabetic stroke treatment.
Matrix metalloproteinases (MMPs) are a family of zinc-dependent endopeptidases that degrade various proteins in the extracellular matrix (ECM). Typically, MMPs have a propeptide sequence, a catalytic metalloproteinase domain with catalytic zinc, a hinge region or linker peptide, and a hemopexin domain. MMPs are commonly classified on the basis of their substrates and the organization of their structural domains into collagenases, gelatinases, stromelysins, matrilysins, membrane-type (MT)-MMPs, and other MMPs. MMPs are secreted by many cells including fibroblasts, vascular smooth muscle (VSM), and leukocytes. MMPs are regulated at the level of mRNA expression and by activation through removal of the propeptide domain from their latent zymogen form. MMPs are often secreted in an inactive proMMP form, which is cleaved to the active form by various proteinases including other MMPs. MMPs degrade various protein substrates in ECM including collagen and elastin. MMPs could also influence endothelial cell function as well as VSM cell migration, proliferation, Ca²⁺ signaling, and contraction. MMPs play a role in vascular tissue remodeling during various biological processes such as angiogenesis, embryogenesis, morphogenesis, and wound repair. Alterations in specific MMPs could influence arterial remodeling and lead to various pathological disorders such as hypertension, preeclampsia, atherosclerosis, aneurysm formation, as well as excessive venous dilation and lower extremity venous disease. MMPs are often regulated by endogenous tissue inhibitors of metalloproteinases (TIMPs), and the MMP/TIMP ratio often determines the extent of ECM protein degradation and tissue remodeling. MMPs may serve as biomarkers and potential therapeutic targets for certain vascular disorders.
We have recently found matrix metalloproteinase-2 (MMP-2) in human platelets and reported that the release of this enzyme during platelet activation stimulates aggregation. We have now identified matrix metalloproteinase-9 (MMP-9) in human platelets and resistance-sized (approximately 200 microm) arteries. Resting platelets released small quantities of pro-MMP-9. Maximal release of MMP-9 was detected during partial (appr. 30% maximum) aggregation with thrombin. However, maximal release of MMP-2 was associated with maximal aggregation. MMP-9 antibodies induced aggregation of resting platelets and potentiated aggregation of platelets induced by thrombin and collagen. Moreover, MMP-9 microisolated from arteries as well as recombinant human MMP-9 (0.1-30 ng/ml) inhibited thrombin and collagen-induced aggregation. We conclude that MMP-9 is an inhibitor of aggregation and in this action opposes the effects of MMP-2. The MMP-2/MMP-9 system may play an important role in the regulation of platelet-platelet and platelet-vessel wall interactions.
Certain matrix metalloproteinases (MMP) are expressed within the fibrous areas surrounding acellular lipid cores of atherosclerotic plaques, suggesting that these proteinases degrade matrix proteins within these areas and weaken the structural integrity of the lesion. We report that matrilysin and macrophage metalloelastase, two broad-acting MMPs, were expressed in human atherosclerotic lesions in carotid endarterectomy samples (n = 18) but were not expressed in normal arteries (n = 7). In situ hybridization and immunohistochemistry revealed prominent expression of matrilysin in cells confined to the border between acellular lipid cores and overlying fibrous areas, a distribution distinct from other MMPs found in similar lesions. Metalloelastase was expressed in these same border areas. Matrilysin was present in lipid-laden macrophages, identified by staining with anti-CD-68 antibody. Furthermore, endarterectomy tissue in organ culture released matrilysin. Staining for versican demonstrated that this vascular proteoglycan was present at sites of matrilysin expression. Biochemical studies showed that matrilysin degraded versican much more efficiently than other MMPs present in atherosclerotic lesions. Our findings suggest that matrilysin, specifically expressed in atherosclerotic lesions, could cleave structural proteoglycans and other matrix components, potentially leading to separation of caps and shoulders from lipid cores.
Blood platelets limit blood loss at sites of vascular injury by forming a mechanical plug. They are also involved in thrombosis, atherosclerosis, inflammation and metastasis. Platelet activation is essential for these physiological and pathological reactions and depends upon their adhesion to the vessel wall and attachment to each other in the aggregation process. The two known pathways of aggregation are mediated by the release of endoperoxides/thromboxane A2 and ADP which amplify platelet aggregation. Here we report the identification of a new pathway of aggregation which is mediated by the release of a metalloproteinase enzyme, gelatinase A.
Thickening and reduplication of the tubular basement membrane has been reported as an early event in diabetic nephropathy. In the current study we examined the effects of elevated D-glucose concentrations on human proximal tubular (HPTC) type IV collagen and fibronectin turnover. Incubation of confluent growth arrested HPTC with 25 mM D-glucose led to accumulation of both type IV collagen and fibronectin. This effect was maximal at 48 hours and represented a sevenfold increase for fibronectin (N = 4, P = 0.04), and a threefold increase for type IV collagen (N = 3, P = 0.03) over cells exposed to 5 mM D-glucose controls. This increase was not dependent on new gene transcription for either protein. Tissue inhibitor of metalloproteinases (TIMP 1 + TIMP 2) were induced following addition of 25 mM D-glucose, but not when cells were exposed to 5 mM D-glucose. Twenty-four hours after the addition of 25 mM D-glucose there was an eightfold increase in TIMP 1 (P = 0.009, N = 4), and a tenfold increase in TIMP 2 levels (P = 0.003, N = 4), over the control values for both inhibitors. The increase in both TIMP 1 and TIMP 2 in response to 25 mM D-glucose was abrogated in a dose dependent manner by the aldose reductase inhibitor sorbinil. Gelatin-substrate gel zymography showed increased activity of gelatinase A, but not of gelatinase B in response to the addition of 25 mM D-glucose to HPTC. The induction of gelatinase A was accompanied by increased gelatinase A mRNA expression, which was inhibited both by protein kinase C (PKC) depletion using PMA pre-treatment, and by the addition of a PKC inhibitor. These data demonstrate that the glucose-induced accumulation of type IV collagen and fibronectin is unrelated to increased gene transcription, but may involve alterations in the degradative pathway of these basement membrane constituents. Furthermore, the data demonstrate that glucose may simultaneously activate two intracellular pathways (the polyol pathway and a PKC dependent activation pathway), which are involved in mediating separate, complementary effects on cell function.
Regulation of mesangial matrix deposition is a dynamic phenomenon involving synthetic and degradative processes. The latter involve a number of matrix metalloproteinases (MMP) and tissue inhibitors of matrix metalloproteinases (TIMP). Experimental studies suggest that mesangial matrix degradation is inhibited in diabetic nephropathy, and that this phenomenon has a pathogenic role. The expression of genes for MMP2 and TIMP2 in human diabetic nephropathy was investigated. Reverse transcription polymerase chain reaction was carried out in microdissected glomeruli and tubulo-interstitium obtained from kidney biopsies. We studied 16 NIDDM patients, 5 patients with glomerulonephritis or chronic kidney transplant rejection, and 5 normal control subjects. Albumin excretion rate and renal histology for NIDDM patients were available. Contrary to TIMP2 which was expressed both in tubulo-interstitium and glomeruli in almost all renal biopsies, MMP2 gene down-regulation was observed in glomeruli from all NIDDM patients, irrespective of the albumin excretion rate, and of renal histology. In contrast, this gene was expressed in biopsies from other subjects (chi(2) = 20.6; p = 0.000). In conclusion, this study demonstrates that: 1) in glomeruli of NIDDM patients the MMP2 gene is down-regulated; 2) in biopsies of NIDDM patients the MMP2/TIMP2 pattern is peculiar for NIDDM; 3) the MMP2 gene down-regulation is observed in all NIDDM patients, irrespective of the level of albuminuria and of renal histology. MMP2 gene down-regulation seems to be a molecular epiphenomenon of diabetes, rather than a marker of diabetic nephropathy.
Type 2 (non-insulin-dependent) diabetes is associated with a marked increase in the risk of coronary heart disease. It has been debated whether patients with diabetes who have not had myocardial infarctions should be treated as aggressively for cardiovascular risk factors as patients who have had myocardial infarctions.
To address this issue, we compared the seven-year incidence of myocardial infarction (fatal and nonfatal) among 1373 nondiabetic subjects with the incidence among 1059 diabetic subjects, all from a Finnish population-based study.
The seven-year incidence rates of myocardial infarction in nondiabetic subjects with and without prior myocardial infarction at base line were 18.8 percent and 3.5 percent, respectively (P<0.001). The seven-year incidence rates of myocardial infarction in diabetic subjects with and without prior myocardial infarction at base line were 45.0 percent and 20.2 percent, respectively (P<0.001). The hazard ratio for death from coronary heart disease for diabetic subjects without prior myocardial infarction as compared with nondiabetic subjects with prior myocardial infarction was not significantly different from 1.0 (hazard ratio, 1.4; 95 percent confidence interval, 0.7 to 2.6) after adjustment for age and sex, suggesting similar risks of infarction in the two groups. After further adjustment for total cholesterol, hypertension, and smoking, this hazard ratio remained close to 1.0 (hazard ratio, 1.2; 95 percent confidence interval, 0.6 to 2.4).
Our data suggest that diabetic patients without previous myocardial infarction have as high a risk of myocardial infarction as nondiabetic patients with previous myocardial infarction. These data provide a rationale for treating cardiovascular risk factors in diabetic patients as aggressively as in nondiabetic patients with prior myocardial infarction.
To estimate the prevalence of diabetes and the number of people with diabetes who are > or =20 years of age in all countries of the world for three points in time, i.e., the years 1995, 2000, and 2025, and to calculate additional parameters, such as sex ratio, urban-rural ratio, and the age structure of the diabetic population.
Age-specific diabetes prevalence estimates were applied to United Nations population estimates and projections for the number of adults aged > or =20 years in all countries of the world. For developing countries, urban and rural populations were considered separately
Prevalence of diabetes in adults worldwide was estimated to be 4.0% in 1995 and to rise to 5.4% by the year 2025. It is higher in developed than in developing countries. The number of adults with diabetes in the world will rise from 135 million in 1995 to 300 million in the year 2025. The major part of this numerical increase will occur in developing countries. There will be a 42% increase, from 51 to 72 million, in the developed countries and a 170% increase, from 84 to 228 million, in the developing countries. Thus, by the year 2025, >75% of people with diabetes will reside in developing countries, as compared with 62% in 1995. The countries with the largest number of people with diabetes are, and will be in the year 2025, India, China, and the U.S. In developing countries, the majority of people with diabetes are in the age range of 45-64 years. In the developed countries, the majority of people with diabetes are aged > or =65 years. This pattern will be accentuated by the year 2025. There are more women than men with diabetes, especially in developed countries. In the future, diabetes will be increasingly concentrated in urban areas.
This report supports earlier predictions of the epidemic nature of diabetes in the world during the first quarter of the 21st century. It also provides a provisional picture of the characteristics of the epidemic. Worldwide surveillance of diabetes is a necessary first step toward its prevention and control, which is now recognized as an urgent priority.
We have previously shown that human platelets express matrix metalloproteinase-2 (MMP-2) and that the release of this enzyme during platelet activation mediates the ADP- and thromboxane-independent part of aggregation. We have now used immunogold electron microscopy, flow cytometry. Western blot analysis and zymography methods to study the ultrastructural localization of MMP-2 in human washed platelets. Platelet aggregation was stimulated by collagen and the MMP-2 immunoreactivity of platelets was followed during various stages of aggregation. In resting platelets, MMP-2 was randomly distributed in the platelet cytosol without detectable association with platelet granules. Platelet aggregation caused the translocation of MMP-2 from the cytosol to the extracellular space. During the early stages of aggregation, MMP-2 remained in close association with the platelet plasma membrane. We conclude that the interactions of MMP-2 with platelet surface membranes mediate the aggregatory response induced by this enzyme.
Stromelysin-3 is an unusual matrix metalloproteinase, being released in the active rather than zymogen form and having a
distinct substrate specificity, targeting serine proteinase inhibitors (serpins), which regulate cellular functions involved
in atherosclerosis. We report here that human atherosclerotic plaques (n = 7) express stromelysin-3 in situ, whereas fatty streaks (n = 5) and normal arterial specimens (n = 5) contain little or no stromelysin-3. Stromelysin-3 mRNA and protein colocalized with endothelial cells, smooth muscle
cells, and macrophages within the lesion. In vitro, usual inducers of matrix metalloproteinases such as interleukin-1, interferon-γ,
or tumor necrosis factor α did not augment stromelysin-3 in vascular wall cells. However, T cell–derived as well as recombinant
CD40 ligand (CD40L, CD154), an inflammatory mediator recently localized in atheroma, induced de novo synthesis of stromelysin-3.
In addition, stromelysin-3 mRNA and protein colocalized with CD40L and CD40 within atheroma. In accordance with the in situ
and in vitro data obtained with human material, interruption of the CD40–CD40L signaling pathway in low density lipoprotein
receptor–deficient hyperlipidemic mice substantially decreased expression of the enzyme within atherosclerotic plaques. These
observations establish the expression of the unusual matrix metalloproteinase stromelysin-3 in human atherosclerotic lesions
and implicate CD40–CD40L signaling in its regulation, thus providing a possible new pathway that triggers complications within
atherosclerotic lesions.
Plasma leptin levels correlate strongly with increased total adipose tissue, a known risk factor for type 2 diabetes, yet the role of leptin in the etiology of diabetes remains unclear. We sought to determine whether leptin is a risk factor for development of diabetes in Japanese Americans.
We compared baseline leptin levels in 370 nondiabetic Japanese Americans who remained nondiabetic for 5-6 years of follow-up with those of 40 nondiabetic Japanese Americans who developed diabetes during follow-up. All participants had computed tomography measurements of baseline subcutaneous chest, abdomen, thigh, and intra-abdominal fat, with total fat defined as the sum of all these measurements.
The mean age was 51.7 +/- 11.7 years for men and 51.9 +/- 12.0 years for women. The 23 men who developed diabetes had significantly higher leptin levels than the 212 men who remained nondiabetic (P < 0.01). Among men, baseline leptin levels predicted diabetes risk independent of baseline total fat, insulin, insulin resistance, glucose, or age in separate multiple logistic regression models (relative risk adjusted for baseline total fat = 1.80 per SD increase [2.7 ng/ml], 95% CI 1.02-3.17). This association was particularly strong among men in the top decile for intra-abdominal fat. In contrast, the 17 women who developed diabetes had leptin levels similar to those of the 158 women who remained nondiabetic (P = 0.31).
Among Japanese Americans, increased baseline leptin levels are associated with increased risk of developing diabetes in men but not in women.
Symptomatic carotid disease resulting from generation of thromboemboli has been associated with plaque instability and intraplaque hemorrhage. These features of the lesion could be influenced by the fragility and position of neovessels within the plaque. The purpose of this study was to determine whether any association exists between neovessel density, position, morphology, and thromboembolic sequelae.
Carotid endarterectomy samples were collected from 15 asymptomatic patients with greater than 80% stenoses and from 13 highly symptomatic patients who had suffered ipsilateral carotid stenotic events within 1 month of surgery. Both groups were matched for gender, age, risk factors, degree of carotid artery stenosis, and plaque size. Samples were stained with hematoxylin/eosin and van Geison. Immunohistochemistry was performed by using an endothelial specific antibody to CD31. Plaques were assessed for histologic characteristics, and neovessels were counted and characterized by size, site, and shape.
There were significantly more neovessels in plaques (P <.00001) and fibrous caps (P <.0001) in symptomatic compared with asymptomatic plaques. Neovessels in symptomatic plaques were larger (P <.004) and more irregular. There was a significant increase in plaque necrosis and rupture in symptomatic plaques. Plaque hemorrhage and rupture were associated with more neovessels within the plaque (P <.017, P <.001) and within the fibrous cap (P <.046, P <.004). Patients with preoperative and intraoperative embolization had significantly more plaque and fibrous cap neovessels (P <.025, P <.001).
Symptomatic carotid disease is associated with increased neovascularization within the atherosclerotic plaque and fibrous cap. These vessels are larger and more irregular and may contribute to plaque instability and the onset of thromboembolic sequelae.
Acute disruption of atherosclerotic plaques precedes the onset of clinical syndromes, and studies have implicated a role for matrix metalloproteinases (MMPs) in this process. The aim of this study was to establish the character, level, and expression of MMPs in carotid plaques and to correlate this with clinical status, cerebral embolization, and histology.
Plaques were obtained from 75 consecutive patients undergoing carotid endarterectomy and divided into 4 groups according to symptomatology (group 1, asymptomatic; group 2, symptomatic >6 months before surgery; group 3, symptomatic within 1 to 6 months; group 4, symptomatic within 1 month). All patients underwent preoperative and intraoperative transcranial Doppler monitoring. Plaques were subjected to histological examination and quantification of MMPs by zymography and ELISA.
The level of MMP-9 was significantly higher in group 4 (median 125.7 ng/mL for group 4, median <32 ng/mL for all other groups; P=0.003), with no difference in the levels of MMPs 1, 2, or 3. Furthermore, the MMP-9 concentration was significantly higher in plaques undergoing spontaneous embolization (P=0.019) and those with histological evidence of plaque instability (P<0.03). In situ hybridization demonstrated increased MMP-9 expression in highly symptomatic plaques in areas of intense inflammatory infiltrate.
The concentration, production, and expression of MMP-9 is significantly higher in unstable carotid plaques. If this proves to be a causal relationship, MMP-9 may be a strong candidate for pharmacotherapy aimed at stabilizing plaques and preventing stroke.
Matrix metalloproteinase 2 (MMP2) has been reported to be secreted by collagen-stimulated platelets, and active MMP2 has been shown to play a role in platelet aggregation. It has been demonstrated that MMP2 activation is dependent on the complex (membrane type 1 [MT1]-MMP/tissue inhibitor of MMP2 [TIMP2]) receptor and MMP2. We have investigated human platelets as a possible source of MT1-MMP, and we have studied its role in MMP2 activation and in platelet aggregation. Gelatin zymograms showed the existence of MMP2 at proforms (68 kd) and activated-enzyme forms (62-59 kd) in supernatants of resting and activated platelets, respectively. No gelatinolytic activity was associated with the platelet pellet after aggregation, suggesting a total release of MMP2 during cell activation. By Western blot analysis in nonreduced conditions, MT1-MMP was found on resting platelet membranes in 2 forms–the inactive 45-kd form and an apparent 89-kd form, which totally disappeared under reduced conditions. After platelet degranulation, only the 45-kd form was detected. Reverse transcription–polymerase chain reaction experiments showed the expression in platelets of messenger RNA encoding for MMP2, MT1-MMP, and TIMP2. Flow cytometry analysis showed that MT1-MMP, MMP2, and TIMP2 expressions were enhanced at the activated platelet surface. MMP inhibitors, recombinant TIMP2, and synthetic BB94 inhibited collagen-induced platelet aggregation in a concentration-dependent manner, indicating the role of activated MT1-MMP in the modulation of platelet function. In conclusion, our results demonstrate the expression of the trimolecular complex components (MT1-MMP/TIMP2/MMP2) by blood platelets as well as the ability of MMP inhibitors to modulate the aggregating response.
Vascular remodeling, defined as any enduring change in the size and/or composition of an adult blood vessel, allows adaptation and repair. On the other hand, inappropriate remodeling, including its absence, underlies the pathogenesis of major cardiovascular diseases, such as atherosclerosis and restenosis. Since degradation of the extracellular matrix scaffold enables reshaping of tissue, participation of specialized enzymes called matrix metalloproteinases (MMPs) has become the object of intense recent interest in relation to physiological (“good”) and pathological (“bad”) vascular remodeling. Experimental evidence acquired in vitro and in vivo suggests that the major drivers of vascular remodeling, hemodynamics, injury, inflammation, and oxidative stress, regulate MMP expression and activity. Alternatively, nonspecific MMP inhibition seems to oppose remodeling, as suggested by the inhibition of intimal thickening and outward arterial remodeling. An emerging concept is that MMP-related genetic variations may contribute to heterogeneity in the presentation and natural history of atherosclerosis. The hypothesis that MMPs contribute to weakening of atherosclerotic plaques is especially attractive for the potential development of therapeutic interventions aimed at preventing plaque disruption (“the ugly”), a major cause of acute cardiovascular events. However, the current lack of appropriate experimental tools, including availability of specific MMP inhibitors and pertinent animal models, still limits our understanding of the many actions and relative contributions of specific MMPs. Our future potential ability to control vascular remodeling via regulation of MMPs will also depend on reaching a consensus of what is indeed “good” or “bad” vascular remodeling, concepts that have continued to evolve and change.
Background There is conflicting evidence on the benefits of foods rich in vitamin E (alpha-tocopherol), n-3 polyunsaturated fatty acids (PUFA), and their pharmacological substitutes. We investigated the effects of these substances as supplements in patients who had myocardial infarction. Methods From October, 1993, to September, 1995, 11324 patients surviving recent (less than or equal to 3 months) myocardial infarction were randomly assigned supplements of n-3 PUFA (Ig daily, n=2836), vitamin E (300 mg daily, n=2830), both (n=2830), or none (control, n=2828) for 3.5 years. The primary combined efficacy endpoint was death, non-fatal myocardial infarction, and stroke. Intention-to-treat analyses were done according to a factorial design (two-way) and by treatment group (four-way). Findings Treatment with n-3 PUFA, but not vitamin E, significantly lowered the risk of the primary endpoint (relative risk decrease 10% [95% CI 1-18] by two-way analysis, 15% [2-26] by four-way analysis). Benefit was attributable to a decrease in the risk of death (14% [3-24] two-way, 20% [6-33] four-way) and cardiovascular death (17% [3-29] two-way, 30% [13-44] four-way). The effect of the combined treatment was similar to that for n-3 PUFA for the primary endpoint (14% [1-26]) and for fatal events (20% [5-33]). Interpretation Dietary supplementation with n-3 PUFA led to a clinically important and satistically significant benefit. Vitamin E had no benefit. Its effects on fatal cardiovascular events require further exploration.
AIM
To examine epiretinal membranes of proliferative diabetic retinopathy (PDR) for the presence of selective matrix metalloproteinases (MMPs) and their natural inhibitors (TIMPs), in order to determine whether neovascularisation and fibrosis, characteristic of this complication of diabetes mellitus, are associated with specific anomalies of MMP or TIMP expression.
METHODS
The presence of selected MMPs and TIMPs was investigated in 24 fibrovascular epiretinal membranes of PDR, and the findings compared with that observed in 21 avascular epiretinal membranes of proliferative vitreoretinopathy (PVR) and five normal retinas. Specimens were examined for deposition of interstitial collagenase (MMP-1), stromelysin-1 (MMP-3), gelatinase A (MMP-2), gelatinase B (MMP-9), and three tissue inhibitors of metalloproteinases (TIMP-1, TIMP-2, and TIMP-3).
RESULTS
The results showed that unlike normal retina, which constitutively expresses MMP-1 and TIMP-2, a large proportion of PDR membranes (> 62%) stained for MMP-1, MMP-2, MMP-3, MMP-9, TIMP-1, TIMP-2, and TIMP-3. There were no differences in the expression of these molecules when compared with PVR membranes. A characteristic staining for MMP-9 was observed within the perivascular matrix of PDR membranes, and there was a significant increase in TIMP-2 expression by PDR membranes (p= 0.036) when compared with PVR membranes.
CONCLUSIONS
The findings that MMPs involved in degradation of fibrovascular tissue matrix, as well as TIMP-1 and TIMP-2, are found in a large proportion of PDR membranes, and that their expression does not differ from that of PVR membranes, suggest the existence of common pathways of extracellular matrix degradation in pathological processes leading to retinal neovascularisation and fibrosis.
Background: Statins reduce cardiovascular events to a greater extent than can be explained by their effect on lipids. Several studies have attempted to elucidate mechanisms by which statins reduce cardiovascular risk. Purpose: To summarize the effects of statins on nonlipid serum markers and to correlate statins' effect on serum markers with lipid levels and cardiovascular outcomes. Data Sources: MEDLINE (1980 to 2003) search limited to English-language articles. Study Selection: Studies reporting original data in at least 10 participants on the effect of statins on outcomes of interest, excluding studies of cerivastatin, drug combinations, and patients with organ transplants. Data Extraction: Study design, sample size, treatment, and outcome data extracted on the basis of preestablished criteria. When appropriate, meta-analysis was performed by using a random-effects model. Data Synthesis: All statins are effective at lowering C-reactive protein levels, and the effect is not dose-dependent. Studies do not demonstrate a correlation between statins' effects on C-reactive protein levels and on lipids or cardiovascular outcomes. Statins do not affect fibrinogen levels, and limited data suggest little effect on lipid oxidation, tissue plasminogen activator, or plasminogen activator inhibitor. Platelet aggregation data are inconclusive. Conclusions: Among nonlipid serum markers examined, only C-reactive protein levels are statistically significantly affected by statins. These findings suggest that statin-mediated anti-inflammatory effects may contribute to the ability of statins to reduce risk for cardiovascular disease. Overall, however, available data are insufficient to support recommendations for using nonlipid serum markers in decisions regarding statin therapy for individual patients.
Background— Several studies suggest a role for an increased circulating pool of tissue factor (TF) in atherothrombotic diseases. Furthermore, certain cardiovascular risk factors, such as diabetes, hyperlipemia, and smoking, are associated with a higher incidence of thrombotic complications. We hypothesized that the observed increased blood thrombogenicity (BT) observed in patients with type 2 diabetes mellitus may be mediated via an increased circulating tissue factor activity. We have extended our study to smokers and hyperlipidemic subjects.
Methods and Results— Poorly controlled patients with type 2 diabetes mellitus (n=36), smokers (n=10), and untreated hyperlipidemic subjects (n=10) were studied. Circulating TF was immunocaptured from plasma, relipidated, and quantified by factor Xa (FXa) generation in the presence of factor VIIa. BT was assessed as thrombus formation on the Badimon perfusion chamber. Patients with improvement in glycemic control showed a reduction in circulating TF (362±135 versus 243±74 pmol/L per min FXa, P=0.0001). A similar effect was observed in BT (15 445±1130 versus 12 072±596 μm/mm², P=0.01). Two hours after smoking 2 cigarettes, TF was increased (217±72 versus 283±106 pmol/L per min FXa, P=0.003). Hyperlipidemic subjects showed higher TF (237±63 versus 195±44 pmol/L per min FXa, P=0.035) than healthy volunteers.
Conclusions— These findings suggest that high levels of circulating TF may be the mechanism of action responsible for the increased thrombotic complications associated with the presence of these cardiovascular risk factors. These observations strongly emphasize the usefulness of the management of the patients based on their global risk assessment.
— Matrix metalloproteinases (MMPs) are proteolytic enzymes that degrade extracellular matrix proteins. These enzymes are implicated in a variety of physiological and pathological events characterized by extracellular matrix remodeling. Recent studies suggest that MMPs may have a signaling capacity, but direct evidence supporting this concept is lacking. In the present study, we demonstrate that outside-in signals delivered by exogenous MMP-1 (interstitial collagenase) markedly increase the number of tyrosine-phosphorylated proteins in platelets. Active MMP-1 also targets β3 integrins to areas of cell contact and primes platelets for aggregation. Examination of the endogenous enzyme demonstrated that activated platelets process latent MMP-1 into its active form. Neutralization of MMP-1 activity with MMP inhibitors or specific blocking antibodies markedly attenuates agonist-induced phosphorylation of intracellular proteins, movement of β3 integrins to cell contact points, and intercellular aggregation. The finding that MMP-1 is rapidly activated in platelets and controls functional responses identifies a new role for this metalloproteinase as a signaling molecule that regulates thrombotic events.
Regulation of the extracellular matrix (ECM) is an important therapeutic target that can potentially attenuate the adverse ventricular remodeling seen in the progression of heart failure. Matrix metalloproteinases (MMPs) degrade numerous ECM proteins. Importantly, the activation of MMPs and their endogenous inhibitors (TIMPs) are associated with ventricular remodeling. Bioactive-molecules (vasoactive peptides) become activated in proportion to the magnitude of heart failure and have been demonstrated to affect directly collagen degradation as well as collagen synthesis in the myocardium. Pro-fibrotic factors such as norepinephrine, angiotensin II, and endothelin-1 stimulate fibrosis by modulating collagen synthesis and MMP/TIMP activity. Antagonism of these bioactive-molecules has produced improved hemodynamic performance concomitant with modulation of MMP/TIMP activity and in association with reverse remodeling. The natriuretic peptides and nitric oxide, both of which function via the second messenger cGMP, demonstrate anti-fibrotic actions by inhibiting collagen synthesis and by stimulating MMP activity. Furthermore, bioactive-molecules along with certain cytokines are reported to amplify MMP activity, suggesting that different signaling systems work together to modulate ECM turnover. Taken together, the evidence supports an important functional role for bioactive-molecules in the regulation of ECM turnover and suggests that pharmacological intervention at the level of such bioactive molecules may provide potential therapeutic strategies for attenuation of the adverse ventricular remodeling associated with the progression of heart failure.
Mononuclear phagocytes play an important role in atherosclerosis and its sequela plaque rupture in part by their secretion of matrix metalloproteinases (MMPs), including MMP-9. Peroxisomal proliferator-activated receptor γ (PPARγ), a transcription factor in the nuclear receptor superfamily, regulates gene expression in response to various activators, including 15-deoxy-Δ12,14-prostaglandin J2 and the antidiabetic agent troglitazone. The role of PPARγ in human atherosclerosis is unexplored. We report here that monocytes/macrophages in human atherosclerotic lesions (n = 12) express immunostainable PPARγ. Normal artery specimens (n = 6) reveal minimal immunoreactive PPARγ. Human monocytes and monocyte-derived macrophages cultured for 6 days in 5% human serum expressed PPARγ mRNA and protein by reverse transcription-polymerase chain reaction and Western blotting, respectively. In addition, PPARγ mRNA expression in U937 cells increased during phorbol 12-myristate 13 acetate-induced differentiation. Stimulation of PPARγ with troglitazone or 15-deoxy-Δ12,14-prostaglandin J2 in human monocyte-derived macrophages inhibited MMP-9 gelatinolytic activity in a concentration-dependent fashion as revealed by zymography. This inhibition correlates with decreased MMP-9 secretion as determined by Western blotting. Thus, PPARγ is present in macrophages in human atherosclerotic lesions and may regulate expression and activity of MMP-9, an enzyme implicated in plaque rupture. PPARγ is likely to be an important regulator of monocyte/macrophage function with relevance for human atherosclerotic disease.
Dysregulated extracellular matrix (ECM) metabolism may contribute to vascular remodeling during atherogenesis. The ability of vascular cells to synthesize the components of ECM is well characterized, but less is known about their capacity to degrade ECM and the factors that may regulate this process. We therefore studied the expression of matrix metalloproteinases (MMPs), enzymes that degrade various components of ECM, and of tissue inhibitors of MMPs (TIMPs) by untreated or cytokine-stimulated human smooth muscle cells (SMC). Messenger RNA was studied by Northern blotting, and proteins secreted in culture by SMC were identified by immunoprecipitation. Gelatinolytic and caseinolytic activity of MMPs was detected zymographically. SMC constitutively produced a 72 kDa type IV gelatinase (GL), TIMP-1, and TIMP-2. Upon stimulation with IL1 or TNF alpha, SMC synthesized in addition 92 kDa GL, stromelysin, and interstitial collagenase, MMPs that together can degrade all of the ECM components. IL1 or TNF alpha did not alter the level of TIMP mRNA and protein, suggesting that a net excess of MMP production under these conditions may promote breakdown of the vascular ECM. To test the in vivo relevance of these in vitro findings, we analyzed immunohistochemically normal human arteries and carotid atheromas. Normal tissue and the medial layer underlying lesions stained uniformly for 72 kDa GL and TIMPs 1 and 2. Lesions showed regionally increased MMP expression: the shoulders of atherosclerotic plaques contained stromelysin and 92 kDa GL associated with SMC, and clusters of macrophage-derived foam cells associated with the lipid core stained intensely for all MMPs studied. Endothelial cells covering atheroma or of the plaque microvasculature contained interstitial collagenase. In pathological conditions associated with local release of cytokines in the vessel wall, enhanced regional expression of vascular MMPs may contribute to SMC migration and weakening of matrix that would favor plaque rupture, events associated with the development or complication of the atherosclerotic lesions.
Peroxisome proliferator-activated receptors (PPARs) are ligand-activated transcription factors that directly control numerous genes of lipid metabolism by binding to response elements in the promoter. It has recently been proposed that PPARγ may also regulate genes for proinflammatory proteins, not through PPRE binding but by interaction with transcription factors AP-1, STAT, and NF-κB. Recent studies with cultured human monocytes, however, have failed to observe an inhibitory effect of PPARγ agonists on induced expression of TNFα and IL-6, genes known to be controlled by AP-1, STAT, and NF-κB. In a similar fashion, we show here that PPARα (fenofibrate) or PPARγ (rosiglitazone) agonists failed to modulate LPS-induced secretion of IL-8 in THP-1 cells. When we made parallel observations on another gene, matrix metalloproteinase 9 (MMP-9), we were surprised to find profound downregulation of LPS-induced secretion by both PPARα or PPARγ agonists. These findings suggest that PPAR may regulate only a subset of the proinflammatory genes controlled by AP-1, STAT, and NF-κB. Effects of PPARs on MMP-9 may account for the beneficial effect of PPAR agonists in animal models of atherosclerosis.
This is a prospective evaluation of the effect of structured care of dyslipidemia with atorvas tatin (strict implementation of guidelines) versus usual care (physician's standard of care) on morbidity and mortality of patients with coronary heart disease (CHD) and diabetes mellitus (DM). From 1600 consecutive CHD patients randomized to either form of care in the GREek Atorvastatin and CHD Evaluation Study (GREACE), 313 had DM: 161 in the structured care arm and 152 in the usual care arm. All patients were followed up for a mean of 3 years. In the structured care group, patients were treated with atorvastatin to achieve the National Cholesterol Education Program (NCEP) low-density lipoprotein cholesterol (LDL-C) treatment goal of < 2.6 mmol/L (100 mg/dL). Primary endpoints were all-cause and coronary mortality, coronary morbidity, and stroke. In the structured care group, 156 patients (97%) were taking atorvastatin (10-80 mg/day; mean, 23.7 mg/day) throughout the study; the NCEP LDL-C treatment goal was reached by 150 patients (93%). Only 17% (n = 26) of the usual care patients were on long-term hypolipidemic drug treatment and 4% (n = 6) reached the NCEP LDL-C treatment goal. During the study, 46 of 152 (30.3%) CHD patients with DM on usual care experienced a major vascular event or died versus 20 of 161 (12.5%) patients on structured care; relative risk reduction (RRR) 58%, p < 0.0001. RRR for all-cause mortality was 52%, p = 0.049; coronary mortality 62%, p = 0.042; coronary morbidity 59%, p < 0.002; and stroke 68%, p = 0.046. Event rate curves started deviating from the sixth treatment month and the RRR was almost 60% by the 12th month. RRRs remained at that level until the end of the study, when they became statistically significant. The cost/life-year gained with structured care was estimated at US $6200. In CHD patients with DM, structured care of dyslipidemia with atorvastatin to achieve the NCEP LDL-C treatment goal, reduces all-cause and coronary mortality, coronary morbidity, and stroke by more than one half within a 3-year period, in comparison to usual care. Clinical benefit is manifested as early as the sixth month of treatment.
Background
We previously reported the prevalence and associations of abdominal aortic aneurysm (AAA) in 73,451 veterans aged 50 to 79 years who underwent ultrasound screening.
Objective
To understand the prevalence of and principal positive and negative risk factors for AAA, and to assess reproducibility of our previous findings.
Methods
In the new cohort of veterans undergoing screening, 52,745 subjects aged 50 to 79 without history of AAA underwent successful ultrasound screening for AAA, after completing a questionnaire on demographics and potential risk factors.
Results
We detected AAA of 4.0 cm or larger in 613 participants (1.2%; compared with 1.4% in the earlier cohort). The direction and magnitude of the important associations reported in the first cohort were confirmed. Respective odds ratios for the major associations with AAA for the second and for the combined cohorts were as follows: 1.81 and 1.71 for age (per 7 years), 0.12 and 0.18 for female sex, 0.59 and 0.53 for black race, 1.94 and 1.94 for family history of AAA, 4.45 and 5.07 for smoking, 0.50 and 0.52 for diabetes, and 1.60 and 1.66 for atherosclerotic diseases. The excess prevalence associated with smoking accounted for 75% of all AAAs of 4.0 cm or larger in the total population of 126,196. Associations for AAA of 3.0 to 3.9 cm were similar but tended to be somewhat weaker.
Conclusions
Our findings confirm our previous cohort findings. Age, smoking, family history of AAA, and atherosclerotic diseases remained the principal positive associations with AAA, and female sex, diabetes, and black race remained the principal negative associations.
Effects of glucose on matrix metalloproteinase and plasmin activities in mesangial cells: Possible role in diabetic nephropathy.Diabetic nephropathy is characterized by an accumulation of mesangium matrix that correlates well with the loss of kidney function. High glucose concentration is known to increase the synthesis of many matrix components. Recently, we have shown that degradation of matrix also decreases in diabetes. The major enzymes responsible for matrix degradation are the matrix metalloproteinases. The physiology of these enzymes is complex and their activity is tightly regulated at many levels. At the transcriptional level matrix metalloproteinase (MMP) expression is increased by protein kinase C (PKC) agonists, and some growth factors. In contrast transforming growth factor (TGF)- can decrease MMP expression. Once synthesized, MMPs are secreted as inactive pro-enzymes that are activated by other MMPs or plasmin. To effect this, plasmin must be liberated from plasminogen in the pericellular environment. In turn, activated MMPs can be inhibited by binding to specific inhibitors known as tissue inhibitor of metalloproteinases (TIMP). Cell culture and animal studies have shown that high glucose (HG) decreases expression of MMPs and increases expression of TIMPs. HG can also affect MMP activation by decreasing plasmin availability and reducing expression of a membrane-bound MMP called MT1-MMP. How HG induces these changes remains to be fully elucidated. One possibility is that HG can increase TGF-, which may in turn alter MMP promoter activity; this area is currently being studied in our laboratory.Keywords: matrix metalloproteinase, plasmin, transforming growth factor-, diabetic nephropathy, matrix degradation
LR: 20061115; JID: 7501160; 0 (Antilipemic Agents); 0 (Cholesterol, HDL); 0 (Cholesterol, LDL); 57-88-5 (Cholesterol); CIN: JAMA. 2001 Nov 21;286(19):2401; author reply 2401-2. PMID: 11712930; CIN: JAMA. 2001 Nov 21;286(19):2400-1; author reply 2401-2. PMID: 11712929; CIN: JAMA. 2001 Nov 21;286(19):2400; author reply 2401-2. PMID: 11712928; CIN: JAMA. 2001 Nov 21;286(19):2400; author reply 2401-2. PMID: 11712927; CIN: JAMA. 2001 May 16;285(19):2508-9. PMID: 11368705; CIN: JAMA. 2003 Apr 16;289(15):1928; author reply 1929. PMID: 12697793; CIN: JAMA. 2001 Aug 1;286(5):533-5. PMID: 11476650; CIN: JAMA. 2001 Nov 21;286(19):2401-2. PMID: 11712931; ppublish
Human mesangial cells (HMC) grown in high glucose environments synthesize excessive amounts of extracellular matrix proteins (ECM). The promoter regions of certain ECM genes contain TPA (phorbol ester)-responsive element (TRE) motifs that bind the transcription factor, activator protein-1 (AP-1), a complex of Jun and other phosphoproteins. AP-1 binding to the TRE promoter is regulated by the quantity, composition and post-translational modifications of proteins in the AP-1 complex. We report an increased binding of AP-1 to TRE oligonucleotides in HMC cultured chronically (5 days) in high glucose environments (30 mM d-glucose). This increased binding is not due to differences in the nuclear quantity of AP-1 proteins or in the composition of the AP-1 complex when compared to AP-1 proteins from cells grown in normal glucose (5 mM d-glucose). A 30 mM l-glucose environment also increased AP-1 binding, but to a degree less than d-glucose. The increased AP-1 binding was partly reversed by treatment of HMC with Calphostin C or Bisindolylmaleimide I suggesting a partial role of the protein kinase C (PKC) pathway in mediating AP-1 binding. AP-1 binding was unaffected by treatment of cells with the MEK inhibitor PD 98059. In addition, increased AP-1 binding persisted for at least 48 hours after media glucose concentrations were normalized. The level of Jun-NH2-terminal kinase (JNK) activity and the phosphorylation of the JNK kinase, SEK1, were unchanged by chronic high glucose concentrations. These studies suggest that in HMC cultured in chronic high glucose, post-translational modifications increase the binding of AP-1 to the TRE motif.
To clarify the roles of metalloproteinases and their inhibitor (TIMP) in diabetic glomerulopathy, we studied the effect of a high glucose concentration on the gene expression of metalloproteinase transin and TIMP as well as collagen type IV and laminin in cultured rat mesangial cells (MCs). In the high glucose group, collagen type IV, laminin, and TIMP mRNA levels were all elevated in a concentration-dependent manner, whereas transin expression was suppressed. Osmotic control of high glucose with mannitol selectively stimulated TIMP expression. We hypothesize that high glucose decreases matrix-degrading activity as well as increases matrix productivity in MCs.
Intraplatelet serotonin (5-HT) content was determined in 23 patients with type I (insulin-dependent) diabetes mellitus (IDDM), 23 patients with type II (non-insulin-dependent) diabetes mellitus (NIDDM), 29 patients with peripheral vascular disease (PVD) and 34 age-matched normal subjects. Intraplatelet 5-HT content in normal subjects showed an age-related decline (r = -0.45; P less than 0.008), as has been previously demonstrated. The median 5-HT content in platelets of the young normal subjects was 4.36 (range: 3.62-6.79) nmol 10(-9) platelets, while that in the elderly normal subjects was 3.87 (range: 2.8-6.0) nmol 10(-9) platelets and that in young + elderly subjects was 4.05 (range: 2.8-6.8) nmol 10(-9) platelets. The median intraplatelet 5-HT content was significantly lower (P less than 0.002) in IDDM patients: 3.0 (range 1.3-6.3), NIDDM patients: 2.5 (range 1.7-5.8), PVD patients: 2.42 (range 0.94-4.98) nmol 10(-9) platelets than that in all young + elderly healthy subjects. The presence of hypertension in DM patients caused a small but significant (P less than 0.05) decrease in intraplatelet 5-HT content, whilst its presence had no effect in PVD patients. In a smaller study, it was established that NIDDM and PVD patients have significantly (P less than 0.002) greater plasma 5-HT concentrations than controls. Insulin-dependent diabetes mellitus patients had greater plasma 5-HT concentrations but this did not achieve statistical significance despite a 66% increment in its value.(ABSTRACT TRUNCATED AT 250 WORDS)
Acute coronary ischemia is usually initiated by rupture of atherosclerotic plaque, leading to intracoronary thrombosis and clinical sequelae. The proximate cause of plaque rupture is unknown. Accordingly, we investigated the potential role of the 92-kD gelatinase member of the matrix metalloproteinase family in acute coronary ischemia.
Coronary atherectomy specimens from patients with atherosclerosis and an acute ischemic syndrome consistent with recent plaque rupture (unstable angina) (n = 12) were immunostained for the presence of 92-kD gelatinase; the results were compared with those obtained by identical study of atherectomy specimens from patients with atherosclerosis and angina but without acute ischemia (stable angina) (n = 12). Positive immunostaining for 92-kD gelatinase was present in 83% of specimens from both unstable and stable angina patients. However, intracellular localization of enzyme (indicating active synthesis) was documented in 10 of 10 positively stained specimens from patients with unstable angina compared with 3 of 10 positively stained specimens from patients with stable angina. Macrophages and smooth muscle cells were the major sources of 92-kD gelatinase in all specimens examined by immunostaining of adjacent sections.
92-kD gelatinase is commonly expressed in coronary arterial atherosclerotic lesions. Active synthesis of 92-kD gelatinase by macrophages and smooth muscle cells in atherosclerotic lesions may play a pathogenic role in the development of acute coronary ischemia.
We investigated serum levels of type III procollagen aminopeptide (CIII), 7S type IV collagen (CIV), and tissue inhibitor of metalloproteinase (TIMP) in 33 patients with type II diabetes mellitus (DM) without uremia (serum creatinine less than 1.5 mg/dl). The patients were divided into three groups based on measurement of the urinary albumin excretion (UAE) index obtained during two morning outpatient clinic visits: non-proteinuric patients (n = 11), UAE index less than 2.26 mg/mmol Cr; patients with microalbuminuria (n = 15), UAE index of 2.26 - 22.6 mg/mmol Cr; and patients with proteinuria (n = 7), UAE index more than 22.6 mg/mmol Cr. Serum levels of CIV and TIMP in patients with microalbuminuria and proteinuria were significantly higher than non-proteinuric patients (ANOVA, p <0.05). Serum levels of CIII in patients with proteinuria were significantly higher than those in non-proteinuric patients (p < 0.05). There was a significant positive correlation between CIV and TIMP (r = 0.502, p < 0.003), but no correlation was observed between CIII and TIMP. These results demonstrated that serum CIII and CIV increases as diabetic nephropathy progresses in terms of increasing proteinuria in type II DM patients, suggesting feasibility and usefulness of measuring serum CIV and CIII in assessing diabetic nephropathy. The increase in TIMP may be, at least in part, a possible cause for the increase in serum CIV in type II DM patients.
Although abdominal aortic aneurysms (AAAs) exhibit increased expression of matrix metalloproteinases (MMPs), the functional balance between MMPs and their tissue inhibitors (TIMPs) remains uncertain. This report compares the proteolytic activity in normal aorta, aorto-occlusive disease (AOD), and AAA by use of a novel in situ zymographic technique.
Infrarenal aortic specimens were obtained from 25 patients undergoing surgery for AOD or AAA and were compared with normal aortic tissue (n = 7) obtained from cadavers. Immunohistochemical staining was performed for collagenase (MMP-1), gelatinase A (MMP-2), stromelysin (MMP-3), TIMP-1, and TIMP-2. Net proteolytic activity was determined with in situ zymography whereby aortic sections were incubated on fluorescently labeled substrate. Proteolytic activity was detected under epifluorescent examination. Compared with normal aortic tissue, AOD and AAA tissue demonstrated marked increases in MMP-1 and MMP-3 immunoreactivity, predominantly in the neointima, and modest increases in TIMP-1. MMP-2 was increased in the diseased aortas, and TIMP-2 was abundant in normal, AOD, and AAA samples. Zymography revealed proteolytic activity in AOD and AAA tissues with active digestion of casein and gelatin substrate, particularly on the luminal portion of the specimens. Normal specimens exhibited no lytic activity. Comparison of AOD and AAA specimens revealed no difference in MMP/TIMP immunoreactivity or net proteolytic activity.
MMP expression is markedly increased in AOD and AAA samples, and an imbalance between MMPs and their inhibitors results in similar proteolytic activity. The eventual formation of aneurysmal or occlusive lesions appears not to result from an ongoing difference in the proteolytic pattern.
Matrix metalloproteinase (MMP) gene expression occurs under tightly regulated mechanisms that lead to cell and tissue-specific expression of the individual genes. Despite this differential expression, there exists a high degree of similarity among the cis-acting elements in the MMP promoters. The Activator Protein-1 (AP-1) site at approximately -70 bp upstream of the transcriptional start site has long been thought to play a dominant role in the transcriptional activation of the MMP promoters, particularly in response to stimulation with phorbol myristate acetate (PMA). However, more recent data indicate that basal transcription, as well as transactivation by PMA, cytokines, and growth factors requires the specific interaction of AP-1 with other cis-acting elements. Particularly important are PEA3 sites, located either adjacent to this AP-1 site or more distally. On the otherhand, the AP-1 site plays a dominant role in repression of MMPs by transforming growth factor beta (TGF-beta), retinoids and glucocorticoids, although some AP-1 independent mechanisms may also contribute. While the AP-1 site is involved in tissue-specific expression of MMPs, the presence of one or more AP-2 elements appears critical. Thus, the AP-1 site, alone, does not regulate transcription of MMPs. Rather, there is an essential interaction with other cis-acting sequences in the promoters and with certain transcription factors that bind to these sequences. Together, these complex interactions control the transcription of the MMPs in response to particular inducers and repressors.
Homozygous mice with a null mutation in the MMP-9/gelatinase B gene exhibit an abnormal pattern of skeletal growth plate vascularization and ossification. Although hypertrophic chondrocytes develop normally, apoptosis, vascularization, and ossification are delayed, resulting in progressive lengthening of the growth plate to about eight times normal. After 3 weeks postnatal, aberrant apoptosis, vascularization, and ossification compensate to remodel the enlarged growth plate and ultimately produce an axial skeleton of normal appearance. Transplantation of wild-type bone marrow cells rescues vascularization and ossification in gelatinase B-null growth plates, indicating that these processes are mediated by gelatinase B-expressing cells of bone marrow origin, designated chondroclasts. Growth plates from gelatinase B-null mice in culture show a delayed release of an angiogenic activator, establishing a role for this proteinase in controlling angiogenesis.
We determined plasma metalloproteinase-9 (MMP-9) concentrations in 30 patients with non-insulin-dependent diabetes mellitus (NIDDM) at an initial examination (baseline) and on three separate occasions during a 48-month follow-up period. All patients had normal urinary albumin excretion (<20 microg/min) at the first three examinations. At the fourth examination (48 months after the first examination), 22 patients had normal urinary albumin excretion and eight had microalbuminuria (median, 36.4 microg/min; range, 20.2 to 46.6 microg/min). Compared with patients with normal urinary albumin excretion, patients with microalbuminuria had significantly higher plasma levels of MMP-9 at the second (56+/-14 microg/L v36+/-12 microg/L; P < 0.05), third (88+/-23 microg/L v 39+/-14 microg/L; P < 0.01), and fourth (117+/-30 microg/L v 44+/-16 microg/L; P < 0.01) examinations, but not at the first examination (34+/-12 microg/L v 33+/-14 microg/L; P=NS). An increase in plasma MMP-9 concentrations preceded the occurrence of microalbuminuria within 4 years. The groups did not differ with regard to age, sex, duration of NIDDM, blood pressure, or mean glycated hemoglobin. In addition, the eight patients with microalbuminuria were treated with an angiotensin-converting enzyme inhibitor (cilazapril; 0.5 mg once daily) for 6 months. Microalbuminuria was reduced to within the normal range, and plasma MMP-9 concentrations were significantly decreased with the cilazapril treatment (52+/-18 microg/L; P < 0.01). However, serum MMP-1 and tissue inhibitor of MMP-1 showed no change during the study period. These data suggest that plasma MMP-9 concentrations preceded and may predict the development of microalbuminuria in NIDDM.
Migration of vascular smooth muscle cells (VSMCs) plays an important role in atherogenesis and restenosis after arterial interventions. The expression of matrix metalloproteinases (MMPs), particularly MMP-9, contributes to VSMC migration. This process requires degradation of basal laminae and other components of the arterial extracellular matrix. Peroxisome proliferator-activated receptors (PPARs), members of the nuclear receptor family, regulate gene expression after activation by various ligands. Recent studies have suggested opposing effects of PPAR gamma (PPARgamma) activation on atherogenesis. The present study tested the hypotheses that human VSMCs express PPAR alpha (PPARalpha) and PPARgamma and that PPAR agonists in VSMCs modulate MMP-9 expression and activity, as well as VSMC migration. Human VSMCs expressed PPARalpha and PPARgamma mRNA and protein. Treatment of VSMCs with the PPARgamma ligands troglitazone and the naturally occurring 15-deoxy-Delta12, 14-prostaglandin J2 (15d-PGJ2) decreased phorbol 12-myristate 13-acetate-induced MMP-9 mRNA and protein levels, as well as MMP-9 gelatinolytic activity in the supernatants in a concentration-dependent manner. Six different PPARalpha activators lacked such effects. Addition of prostaglandin F2alpha, known to limit PPARgamma activity, diminished the MMP-9 inhibition seen with either troglitazone or 15d-PGJ2, further implicating PPARgamma in these effects. Finally, troglitazone and 15d-PGJ2 inhibited the platelet-derived growth factor-BB-induced migration of VSMCs in vitro in a concentration-dependent manner. PPARgamma activation may regulate VSMC migration and expression and activity of MMP-9. Thus, PPARgamma activation in VSMCs, via the antidiabetic agent troglitazone or naturally occurring ligands, may act to counterbalance other potentially proatherosclerotic PPARgamma effects.
Diabetes is a major risk factor for coronary and peripheral artery diseases. Although diabetic patients often present with advanced forms of these diseases, it is not known whether the compensatory mechanisms to vascular ischemia are affected in this condition. Accordingly, we sought to determine whether diabetes could: 1) impair the development of new collateral vessel formation in response to tissue ischemia and 2) inhibit cytokine-induced therapeutic neovascularization. Hindlimb ischemia was created by femoral artery ligation in nonobese diabetic mice (NOD mice, n = 20) and in control C57 mice (n = 20). Hindlimb perfusion was evaluated by serial laser Doppler studies after the surgery. In NOD mice, measurement of the Doppler flow ratio between the ischemic and the normal limb indicated that restoration of perfusion in the ischemic hindlimb was significantly impaired. At day 14 after surgery, Doppler flow ratio in the NOD mice was 0.49+/-0.04 versus 0.73+/-0.06 for the C57 mice (P< or =0.005). This impairment in blood flow recovery persisted throughout the duration of the study with Doppler flow ratio values at day 35 of 0.50+/-0.05 versus 0.90+/-0.07 in the NOD and C57 mice, respectively (P< or =0.001). CD31 immunostaining confirmed the laser Doppler data by showing a significant reduction in capillary density in the NOD mice at 35 days after surgery (302+/-4 capillaries/mm2 versus 782+/-78 in C57 mice (P< or =0.005). The reduction in neovascularization in the NOD mice was the result of a lower level of vascular endothelial growth factor (VEGF) in the ischemic tissues, as assessed by Northern blot, Western blot and immunohistochemistry. The central role of VEGF was confirmed by showing that normal levels of neovascularization (compared with C57) could be achieved in NOD mice that had been supplemented for this growth factor via intramuscular injection of an adenoviral vector encoding for VEGF. We conclude that 1) diabetes impairs endogenous neovascularization of ischemic tissues; 2) the impairment in new blood vessel formation results from reduced expression of VEGF; and 3) cytokine supplementation achieved by intramuscular adeno-VEGF gene transfer restores neovascularization in a mouse model of diabetes.
Although myocardial ischemia is known to be significantly related to the development of coronary collateral vessels (CCVs), there is considerable variation between patients with ischemic heart disease in the presence of collateral development. The nature of this variability is not well known. Likewise, it remains unclear whether diabetes mellitus (DM) has any effect on CCVs. The aim of this study was to evaluate the effect of DM on CCVs.
Of the patients who underwent coronary angiography during the interval between March 1, 1993, and June 20, 1998, in our institution, 306 were diabetic. Those patients in whom coronary angiography is normal or severity of coronary artery stenosis is thought not to be sufficient for the development of CCVs (<75%) were excluded from the study. A total of 205 patients (mean age, 59+/-8 years) met the criteria for the DM group. For case-control matching, 205 consecutive nondiabetic patients (mean age, 58+/-9 years) who had >/=1 diseased vessel with >75% stenosis were included in the control group. The CCVs were graded according to the Rentrop scoring system, and the collateral score was calculated by summing the Rentrop numbers of every patient. There was no statistical difference between patients with and without DM in clinical baseline characteristics. The mean number of diseased vessels in the DM group (1.58+/-0.68) was higher than that in the nondiabetic group (1.42+/-0.65, P=0.005). The mean collateral score was 2.41+/-2.20 in the DM group and 2.60+/-2.39 in the control group. After confounding variables were controlled for, the collateral score in the diabetic group was significantly different from that in the nondiabetic group (P=0.034).
Our findings suggest that CCV development is poorer in patients with than in patients without DM. Thus, we can speculate that DM is an important factor affecting CCV development.
Several recent studies attempted to classify plaques as those prone to cause clinical manifestations (vulnerable, atheromatous plaques) or those less frequently associated with acute thrombotic complication (stable, fibrous plaques). Defining the cellular and molecular mechanisms that underlie these morphological features remains a challenge. Because interstitial forms of collagen determine the biomechanical strength of the atherosclerotic lesion, this study investigated expression of the collagen-degrading matrix metalloproteinase (MMP) interstitial collagenase-3 (MMP-13) and the previously studied MMP-1 in human atheroma and used a novel technique to test the hypothesis that collagenolysis in atheromatous lesions exceeds that in fibrous human atherosclerotic lesions.
Human carotid atherosclerotic plaques, similar in size, were separated by conventional morphological characteristics into fibrous (n=10) and atheromatous (n=10) lesions. Immunohistochemical and Western blot analysis demonstrated increased levels of MMP-1 and MMP-13 in atheromatous versus fibrous plaques. In addition, collagenase-cleaved type I collagen, demonstrated by a novel cleavage-specific antibody, colocalized with MMP-1- and MMP-13-positive macrophages. Macrophages, rather than endothelial or smooth muscle cells, expressed MMP-13 and MMP-1 on stimulation in vitro. Furthermore, Western blot analysis demonstrated loss of interstitial collagen type I and increased collagenolysis in atheromatous versus fibrous lesions. Finally, atheromatous plaques contained higher levels of proinflammatory cytokines, activators of MMPs.
This report demonstrates that atheromatous rather than fibrous plaques might be prone to rupture due to increased collagenolysis associated with macrophages, probably mediated by the interstitial collagenases MMP-1 and MMP-13.
Matrix metalloproteinases (MMPs) are expressed in atherosclerotic plaques, where in their active form, they may contribute to vascular remodeling and plaque disruption. In this study, we tested the hypothesis that membrane type 1 MMP (MT1-MMP), a novel transmembrane MMP that activates pro-MMP-2 (gelatinase A), is expressed in human atherosclerotic plaques and that its expression is regulated by proinflammatory molecules.
MT1-MMP expression was examined in normal and atherosclerotic human arteries by immunocytochemistry with specific antibodies. MT1-MMP expression in human saphenous vein-derived smooth muscle cells (SMCs) maintained in tissue culture was determined under basal conditions and in response to proinflammatory molecules (interleukin [IL]-1alpha, tumor necrosis factor [TNF]-alpha, and oxidized LDL [ox-LDL]) by use of Northern blot and ribonuclease protection assays for mRNA, Western blot and immunoprecipitation for protein, and gelatin zymography for catalytic activity. Medial SMCs of normal vessel wall expressed MT1-MMP. In atherosclerotic arteries, MT1-MMP expression was noted within the complex atheroma colocalizing with SMCs and macrophages (Mphi). Cultured SMCs constitutively expressed MT1-MMP mRNA and protein, which increased 2- to 4-fold over control in a time-dependent manner within 4 to 8 hours of exposure to IL-1alpha, TNF-alpha, and ox-LDL (thiobarbituric acid-reactive substances, 13.4 nmol/mg LDL protein), whereas native LDL had no effect. Flow cytometry revealed MT1-MMP expression by human monocyte-derived Mphi, which increased 3.8-fold over baseline within 6 hours after exposure to 10 ng/mL TNF-alpha.
This study demonstrates that MT1-MMP, an activator of pro-MMP-2, is expressed by SMCs and Mphi in human atherosclerotic plaques. Furthermore, proinflammatory molecules upregulate MT1-MMP expression in vascular SMCs and Mphi. Thus, activation of SMCs and Mphi by proinflammatory molecules may influence extracellular matrix remodeling in atherosclerosis by regulating MT1-MMP expression.
Wound healing is characterized by hemostasis, re-epithelialization, granulation tissue formation, and remodeling of the extracellular matrix. Matrix metalloproteinases and their specific inhibitors, TIMPs, contribute to these events. We investigated a total of 47 samples of normally healing wounds, chronic venous ulcers, ulcerative vasculitis, and suction blisters using immunohistochemistry and in situ hybridization, to clarify the role of TIMPs in normal and aberrant wound repair. Expression of TIMP-1 and -3 mRNAs was found in proliferating keratinocytes in 3- to 5-day-old normally healing wounds, whereas no epidermal expression was detected in chronic ulcers. However, TIMP-3 protein was found in the proliferating epidermis in 20 of 24 samples representing both full-thickness acute and chronic wounds. TIMP-1 and TIMP-3 also were abundantly expressed by spindle-shaped, fibroblast-like, and plump, macrophage-like stromal cells, as well as by endothelial cells. In normally healing wounds, TIMP-2 protein localized under the migrating epithelial tip and to the stromal tissue under the eschar more frequently than in chronic ulcers. Occasional staining for TIMP-4 protein was detected in stromal cells of chronic ulcers near blood vessels. Our results indicate that TIMP-1 and TIMP-3 may be involved both in the regeneration of the epidermis by stabilizing the basement membrane zone and in the regulation of stromal remodeling and angiogenesis of the wound bed. Lack of TIMP-2 near the migrating epithelial wound edges might contribute to uncontrolled activity of MMP-2 in chronic ulcers. We conclude also that TIMPs are temporally and spatially tightly regulated and that the imbalance between metalloproteinases and TIMPs-1, -2, and -3 may lead to delayed wound healing.
Both Type I and Type II diabetes mellitus (DM) have been associated with unusually aggressive periodontitis. Accordingly, rat models of both types of DM were used to study (i) mechanisms mediating this systemic/local interaction and (ii) new pharmacologic approaches involving a series of chemically modified tetracyclines (CMTs) that have lost their antimicrobial but retained their host-modulating (e.g., MMP-inhibitory) properties. In vitro experiments on tissues from Type I DM rats demonstrated that several of these CMTs were better matrix metalloproteinase (MMP) inhibitors than was antibacterial doxycycline (doxy), except for CMT-5, which, unlike the other MMP inhibitors, was found not to react with zinc. Data from in vivo studies on the same rat model generally supported the relative efficacy of these compounds: the CMTs and doxy were found to inhibit MMP activity, enzyme expression, and alveolar bone loss. To examine other long-term complications such as nephropathy and retinopathy, a Type II (ZDF) model of DM was studied. Treatment of these DM rats with CMT-8 produced a 37% (p < 0.05), 93% (p < 0.001), and 50% (p < 0.01) reduction in the incidence of cataract development, proteinuria, and tooth loss, respectively; whereas the doxy-treated ZDF rats showed little or no effect on these parameters. CMT treatment decreased mortality of the Type II ZDF diabetic animals, clearly indicating that CMTs, but not commercially available antibiotic tetracyclines (TCs), may have therapeutic applications for the long-term management of diabetes.
This statement examines the cardiovascular complications of diabetes mellitus and considers opportunities for their prevention. These complications include coronary heart disease (CHD), stroke, peripheral arterial disease, nephropathy, retinopathy, and possibly neuropathy and cardiomyopathy. Because of the aging of the population and an increasing prevalence of obesity and sedentary life habits in the United States, the prevalence of diabetes is increasing. Thus, diabetes must take its place alongside the other major risk factors as important causes of cardiovascular disease (CVD). In fact, from the point of view of cardiovascular medicine, it may be appropriate to say, “diabetes is a cardiovascular disease.”
The most prevalent form of diabetes mellitus is type 2 diabetes. This disorder typically makes its appearance later in life. The underlying metabolic causes of type 2 diabetes are the combination of impairment in insulin-mediated glucose disposal (insulin resistance) and defective secretion of insulin by pancreatic β-cells. Insulin resistance develops from obesity and physical inactivity, acting on a substrate of genetic susceptibility.1 2 Insulin secretion declines with advancing age,3 4 and this decline may be accelerated by genetic factors.5 6 Insulin resistance typically precedes the onset of type 2 diabetes and is commonly accompanied by other cardiovascular risk factors: dyslipidemia, hypertension, and prothrombotic factors.7 8 The common clustering of these risk factors in a single individual has been called the metabolic syndrome. Many patients with the metabolic syndrome manifest impaired fasting glucose (IFG)9 even when they do not have overt diabetes mellitus.10 The metabolic syndrome commonly precedes the development of type 2 diabetes by many years11 ; of great importance, the risk factors that constitute this syndrome contribute independently to CVD risk.
Recently, new criteria have been accepted for the diagnosis of diabetes.9 The upper threshold of fasting plasma glucose for the …
Subjects who convert to type 2 diabetes mellitus have increased cardiovascular risk factors relative to nonconverters. However, it is not known whether these atherogenic changes in the prediabetic state are predominantly due to insulin resistance, decreased insulin secretion, or both.
We examined this issue in the 7-year follow-up of the San Antonio Heart Study, in which 195 of 1734 subjects converted to type 2 diabetes. At baseline, converters had significantly higher body mass index, waist circumference, triglyceride concentration, and blood pressure and lower HDL cholesterol than nonconverters. Atherogenic changes in converters were markedly attenuated (and no longer significant) after adjustment for the homeostasis model assessment of insulin resistance (HOMA IR, a surrogate for insulin resistance); in contrast, the differences in risk factors between converters and nonconverters increased after adjustment for the ratio of early insulin increment to early glucose increment (DeltaI(30-0)/DeltaG(30-0)) during an oral glucose tolerance test (a surrogate for insulin secretion). We also compared converters who had a predominant insulin resistance (high HOMA IR and high DeltaI(30-0)/DeltaG(30-0)) (n=56) and converters who had a predominant decrease in insulin secretion (low HOMA IR and low DeltaI(30-0)/DeltaG(30-0)) (n=31) with nonconverters (n=1539). Only the converters who were insulin resistant had higher blood pressure and triglyceride levels and lower HDL cholesterol levels than nonconverters.
Our data suggest that atherogenic changes in the prediabetic state are mainly seen in insulin-resistant subjects and that strategies to prevent type 2 diabetes might focus on insulin-sensitizing interventions rather than interventions that increase insulin secretion because of potential effects on cardiovascular risk.
Abdominal aortic aneurysms (AAAs) have historically been considered to be a manifestation of atherosclerosis. However, there are epidemiologic and biochemical differences between occlusive atherosclerotic disease and aneurysmal disease of the aorta. A case-control study was performed to investigate risk factors for AAA at the two tertiary care hospitals in Winnipeg, Manitoba, Canada, between June 1992 and December 1995 to investigate risk factors for AAA. Newly diagnosed cases of AAA (n = 98) were compared with non-AAA controls (n = 102), who underwent ultrasound for indications similar to those of the cases. Compared with that for never smokers, the adjusted odds ratio (OR) was 2.75 (95% confidence interval (CI): 0.85, 8.91) for 1-19 pack-years, 7.31 (95% CI: 2.44, 21.9) for 20-34 pack-years, 7.35 (95% CI: 2.40, 22.5) for 35-49 pack-years, and 9.55 (95% CI: 2.81, 32.5) for 50 or more pack-years. Other factors significantly associated with AAA were male gender (OR = 2.68, 95% CI: 1.26, 5.73), diastolic blood pressure (OR per 10 mmHg = 1.88, 95% CI: 1.31, 2.69), and family history of AAA (OR = 4.77, 95% CI: 1.26, 18.1). There was an inverse association between diabetes mellitus and AAA (OR = 0.32, 95% CI: 0.12, 0.88). Neither clinical hypercholesterolemia nor serum levels of total cholesterol, low density lipoprotein cholesterol, and high density lipoprotein cholesterol was associated with AAA. The results of this study suggest that the risk factors for AAA differ from those for atherosclerosis and that atherosclerosis per se is not an adequate explanation as the cause of AAAs.