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Extracellular superoxide dismutase and cardiovascular disease
Abstract
Excessive production and/or inadequate removal of reactive oxygen species, especially superoxide anion (O(2)(*-)), have been implicated in the pathogenesis of many cardiovascular diseases, including atherosclerosis, hypertension, diabetes, and in endothelial dysfunction by decreasing nitric oxide (NO) bioactivity. Since the vascular levels of O(2)(*-) are regulated by the superoxide dismutase (SOD) enzymes, a role of SOD in the cardiovascular disease is of substantial interest. Particularly, a major form of SOD in the vessel wall is the extracellular SOD (ecSOD). This review will discuss the characteristics of ecSOD and the role of ecSOD in cardiovascular diseases.
... Humans are continually exposed to RONS from both endogenous (e.g., from aerobic metabolism and the immune response) and exogenous sources (e.g., tobacco smoke, UV light, etc.) and thus, antioxidants function to help prevent/curb high levels of oxidative stress and maintain redox homeostasis. Accordingly, aerobic organisms possess an intricate antioxidant defence system [35] that comprises an orchestrated synergism between several endogenous and exogenous antioxidants attempting to control the RONS produced in cells and tissues [36,37] which arise as a consequence of everyday activities such as the food we eat [38]. Oxidative stress is defined as 'an imbalance between oxidants and antioxidants in favor (sic) of the oxidants, leading to a disruption of redox signaling (sic) and control' [39]. ...
... •− production that was subsequently able to react with endothelium-derived NO • (via eNOS) to impair blood vessel function. The consequences of this (and similar reactions that elevate vascular RONS) may be detrimental to cardiovascular function by reducing NO • bioactivity and increasing the formation of the ONOO − [37], possibly leading to endothelial dysfunction and a pro-atherogenic environment [5]. ONOO − interacts with lipids, DNA, and proteins via direct or indirect radical mechanisms, and its generation has been cited in the pathogenesis of stroke, myocardial infarction, atherosclerosis, circulatory shock, and chronic inflammatory diseases [99,100]. ...
Compelling research has documented how the circadian system is essential for the maintenance of several key biological processes including homeostasis, cardiovascular control, and glucose metabolism. Circadian clock disruptions, or losses of rhythmicity, have been implicated in the development of several diseases, premature ageing, and are regarded as health risks. Redox reactions involving reactive oxygen and nitrogen species (RONS) regulate several physiological functions such as cell signalling and the immune response. However, oxidative stress is associated with the pathological effects of RONS, resulting in a loss of cell signalling and damaging modifications to important molecules such as DNA. Direct connections have been established between circadian rhythms and oxidative stress on the basis that disruptions to circadian rhythms can affect redox biology, and vice versa, in a bi-directional relationship. For instance, the expression and activity of several key antioxidant enzymes (SOD, GPx, and CAT) appear to follow circadian patterns. Consequently, the ability to unravel these interactions has opened an exciting area of redox biology. Exercise exerts numerous benefits to health and, as a potent environmental cue, has the capacity to adjust disrupted circadian systems. In fact, the response to a given exercise stimulus may also exhibit circadian variation. At the same time, the relationship between exercise, RONS, and oxidative stress has also been scrutinised, whereby it is clear that exercise-induced RONS can elicit both helpful and potentially harmful health effects that are dependent on the type, intensity, and duration of exercise. To date, it appears that the emerging interface between circadian rhythmicity and oxidative stress/redox metabolism has not been explored in relation to exercise. This review aims to summarise the evidence supporting the conceptual link between the circadian clock, oxidative stress/redox homeostasis, and exercise stimuli. We believe carefully designed investigations of this nexus are required, which could be harnessed to tackle theories concerned with, for example, the existence of an optimal time to exercise to accrue physiological benefits.
... SOD, one of the most primitive antioxidant enzymes found in human and other mammals, has three isomeric forms (Miao and Clair, 2009); all isoenzymes function to the removal of superoxide anion and suppress OS. It has been found that there is a marked increase in SOD3 activity in atherosclerotic lesion (Fukai et al., 2002). Catalase functions in the decomposition of hydrogen peroxide, which is derived from SOD activity or from any other sources, and thus protects the cellular components from oxidative damage (Chelikani et al., 2004). ...
... One study found that anemia could affect the clinical outcomes in ACS patients (Keough-Ryan et al., 2005). In erythrocytes, SOD1 plays the major role as enzymatic antioxidant to control the level of ROS (Fukai et al., 2002) along with catalase and GPx. Therefore, increase in OS may have some effect on the activity of enzymatic antioxidants. ...
Destabilization of atherosclerotic plaque in the coronary artery is the result of Oxidative Stress (OS) that damage the myocardial tissues in Acute Coronary Syndrome (ACS). This study investigated the activities of certain circulatory and cellular antioxidant- and glutathione-associated enzymes in ACS patients in comparison to a control group. Standard assay methods were followed to evaluate the activities of Superoxide Dismutase (SOD), catalase, Glutathione-S-transferase (GST), Glutathione Peroxidase (GPx) and Glutathione Reductase (GR). For data analysis, the categorical variables were measured in percentages, and continuous variables were expressed in means and standard deviations. The ACS patients had significantly higher activities of circulatory SOD, GPx and GST compared to the controls (4.36 ± 2.28 U/mL, 49.20 ± 14.12 U/mL and 5.02 ± 3.03 U/mL versus 2.87 ± 1.28 U/mL, 21.53 ± 10.80 U/mL and 3.03 ± 1.99 U/mL, respectively) but their catalase and GR activities were significantly lower. While the catalase activities in the erythrocyte and leukocyte lysates were similar in both groups, the leukocyte SOD activity was significantly lower in patients. A significant positive correlation was found between the GR and catalase activities in patients. The circulatory enzymes SOD, GPx and GST are over-expressed in controlling excessive OS, while the reduced activities of catalase and GR could be the consequence, suggesting therapeutic potentials of using enzymes in reducing OS-mediated endothelial injury in ACS patients.
... Superoxide radicals are intimately involved in oxidative stress and easily converted to other ROS, making it complicated to evaluate their pathogenic pathways [33]. High levels of ROS, especially superoxide radicals, have been implicated in cardiovascular diseases (heart failure, hypertension, diabetes, hypercholesterolemia, and atherosclerosis), Parkinson's disease, and cancers [34,35]. As a natural antioxidant enzyme, superoxide dismutase (SOD) uses metal as a cofactor and catalyzes the dismutation of superoxide radicals to hydrogen peroxide and oxygen. ...
Antioxidant enzymes such as catalase, superoxide dismutase, and glutathione peroxidase play important roles in the inhibition of oxidative-damage-related pathological diseases. However, natural antioxidant enzymes face some limitations, including low stability, high cost, and less flexibility. Recently, antioxidant nanozymes have emerged as promising materials to replace natural antioxidant enzymes for their stability, cost savings, and flexible design. The present review firstly discusses the mechanisms of antioxidant nanozymes, focusing on catalase-, superoxide dismutase-, and glutathione peroxidase-like activities. Then, we summarize the main strategies for the manipulation of antioxidant nanozymes based on their size, morphology, composition, surface modification, and modification with a metal-organic framework. Furthermore, the applications of antioxidant nanozymes in medicine and healthcare are also discussed as potential biological applications. In brief, this review provides useful information for the further development of antioxidant nanozymes, offering opportunities to improve current limitations and expand the application of antioxidant nanozymes.
... Superoxide dismutase (SOD) is an enzyme that scavenges superoxide anion, thereby regulating the downstream reaction of superoxide with nitric oxide to form peroxynitrite anion, a reaction responsible for many pathological proceses [196]. SOD is a thought to correlate directly with the body' level of OS. ...
Oxidative stress (OS) is mediated by reactive oxygen species (ROS), which in cardiovascular and other disease states, damage DNA, lipids, proteins, other cellular and extra-cellular components. OS is both initiated by, and triggers inflammation, cardiomyocyte apoptosis, matrix remodeling, myocardial fibrosis, and neurohumoral activation. These have been linked to the development of heart failure (HF). Circulating biomarkers generated by OS offer potential utility in patient management and therapeutic targeting. Novel OS-related biomarkers such as NADPH oxidases (sNox2-dp, Nrf2), advanced glycation end-products (AGE), and myeloperoxidase (MPO), are signaling molecules reflecting pathobiological changes in HF. This review aims to evaluate current OS-related biomarkers and their associations with clinical outcomes and to highlight those with greatest promise in diagnosis, risk stratification and therapeutic targeting in HF.
... NO upregulates SOD3 expression in human VSMCs [60]. However, SOD3 expression may be decreased in atherosclerosis due to reductions in NO bioavailability [61]. The effect of SOD-3 on atherogenesis is unclear; after one month of high fat feeding SOD-3 deletion led to a slight decrease in plaque area but by three months no differences were observed [62]. ...
Atherosclerosis is a chronic inflammatory disease of the vascular system and is the leading cause of cardiovascular diseases worldwide. Excessive generation of reactive oxygen species (ROS) leads to a state of oxidative stress which is a major risk factor for the development and progression of atherosclerosis. ROS are important for maintaining vascular health through their potent signalling properties. However, ROS also activate pro-atherogenic processes such as inflammation, endothelial dysfunction and altered lipid metabolism. As such, considerable efforts have been made to identify and characterise sources of oxidative stress in blood vessels. Major enzymatic sources of vascular ROS include NADPH oxidases, xanthine oxidase, nitric oxide synthases and mitochondrial electron transport chains. The production of ROS is balanced by ROS-scavenging antioxidant systems which may become dysfunctional in disease, contributing to oxidative stress. Changes in the expression and function of ROS sources and antioxidants have been observed in human atherosclerosis while in vitro and in vivo animal models have provided mechanistic insight into their functions. There is considerable interest in utilising antioxidant molecules to balance vascular oxidative stress, yet clinical trials are yet to demonstrate any atheroprotective effects of these molecules. Here we will review the contribution of ROS and oxidative stress to atherosclerosis and will discuss potential strategies to ameliorate these aspects of the disease.
... Aerobic cells possess antioxidant systems, which combat the production of ROS, in particular, the superoxide anion (0 2 _) during cellular respiration and substrate oxidation (Martin, 1984, Hinshaw et al., 1992, Berman and Martin, 1993, Meharg et al., 1993, Doan et al., 1994, Okayama et aI., 1997. The presence of ROS at low levels is vital for biochemical survival, as they often represent an integral part of intracellular signalling and immunological defence mechanisms (KeIrn et aI., , Fukai et al., 2002, Klink et aI., 2003. ...
p>Peripheral neuropathy is an insidious complication of diabetes mellitus with notable secondary events, such as vascular dysfunction and plantar ulceration. Traditional doctrine maintains that diabetic ulceration is a direct consequence of concurrent neuropathy and pressure. It was hypothesised that neuropathic ulceration is promoted by capillary occlusion, the resultant hypoxia leading to expeditious cell death. The Golgi enzyme, core 2 transferase, was implicated in this event, given its mediation of intercellular signalling and leukocyte / endothelial adhesion. Hence, an upregulation of this particular facilitator would increase leukocyte / endothelial binding and thereby, effect microcirculatory stasis and post-occlusion ischaemia.
Type II diabetic study groups, with and without neuropathy (n=20), were canvassed and set against aged matched non-diabetic controls (n=5). All participants were subjected to anthropometric testing prior to venous blood sampling for the key marker, core 2 transferase. Additional blood chemistry and clinical testing (VPT and 10g monofilament) was further undertaken to demonstrate possible correlations with core 2 transferase upregulation.
The outcome of this study identified that core 2 transferase was significantly elevated in both diabetic study groups, in comparison to control participants (p<0.001). This trend was further continued, when comparing diabetic neuropathic individuals to both remaining groups (p<0.001). Subsequent linear regression modelling identified three principal correlations with core 2 transferase over-expression: VPT, 10g monofilament and creatinine levels. Using each of the above correlations as independent co-variates, adjusted models identified a very robust Rsq of 0.911 (91% predictability) for VPT and creatinine, as clinical markers for core 2 transferase specificity.
Consequently, these findings positively implicate core 2 transferase activity within a diabetic population and moreover, offer validated clinical tools to facilitate its early detection.</p
... The MnSOD2 resides in the mitochondrial matrix [97]. Lastly, the Cu/Zn SOD SOD3 is typically released into the extracellular space (Table 2) [98]. ...
Chemotherapy-induced intestinal mucositis (CIM) is a significant dose-limiting adverse reaction brought on by the cancer treatment. Multiple studies reported that reactive oxygen species (ROS) is rapidly produced during the initial stages of chemotherapy, when the drugs elicit direct damage to intestinal mucosal cells, which, in turn, results in necrosis, mitochondrial dysfunction, and ROS production. However, the mechanism behind the intestinal redox system-based induction of intestinal mucosal injury and necrosis of CIM is still undetermined. In this article, we summarized relevant information regarding the intestinal redox system, including the composition and regulation of redox enzymes, ROS generation, and its regulation in the intestine. We innovatively proposed the intestinal redox “Tai Chi” theory and revealed its significance in the pathogenesis of CIM. We also conducted an extensive review of the English language-based literatures involving oxidative stress (OS) and its involvement in the pathological mechanisms of CIM. From the date of inception till July 31, 2021, 51 related articles were selected. Based on our analysis of these articles, only five chemotherapeutic drugs, namely, MTX, 5-FU, cisplatin, CPT-11, and oxaliplatin were shown to trigger the ROS-based pathological mechanisms of CIM. We also discussed the redox system-mediated modulation of CIM pathogenesis via elaboration of the relationship between chemotherapeutic drugs and the redox system. It is our belief that this overview of the intestinal redox system and its role in CIM pathogenesis will greatly enhance research direction and improve CIM management in the future.
... Both microminerals and macrominerals quantified are not very far from the reference values collected by Costa et al. [9] for Laminaria sp. Zinc, manganese and copper display a key cofactor role of antioxidant enzymes, such as superoxide dismutase [43]. As far it concerns to iron, this metallic chemical element is known to be essential to life, but it is poorly soluble in biological fluids and toxic when exists in excess. ...
Background
The Laminaria digitata is an abundant macroalga and a sustainable feedstock for poultry nutrition. L. digitata is a good source of essential amino acids, carbohydrates and vitamins, including A, D, E, and K, as well as triacylglycerols and minerals, in particular iron and calcium. However, the few studies available in the literature with broilers document the application of this macroalga as a dietary supplement rather than a feed ingredient. No study has addressed up until now the effects of a high-level incorporation (> 2% in the diet) of L. digitata on plasma biochemical markers and hepatic lipid composition, as well as minerals and pigments profile in the liver of broilers. Our experimental design included one hundred and twenty Ross 308 male birds contained in 40 wired-floor cages and distributed to the following diets at 22 days of age ( n = 10) for 15 days: 1) a corn-soybean basal diet (Control); 2) the basal diet plus 15% of L. digitata (LA); 3) the basal diet plus 15% of L. digitata with 0.005% of Rovabio® Excel AP (LAR); and 4) the basal diet plus 15% of L. digitata with 0.01% of the recombinant CAZyme, alginate lyase (LAE).
Results
L. digitata compromised birds’ growth performance by causing a reduction in final body weight. It was found an increase in hepatic n -3 and n -6 fatty acids, in particular C18:2 n -6, C18:3 n -6, C20:4 n -6, C20:5 n -3, C22:5 n -3 and C22:6 n -3 with the addition of the macroalga, with or without feed enzymes, to the broiler diets. Also, the beneficial C18:3 n -3 fatty acid was increased by combining L. digitata and commercial Rovabio® Excel AP compared to the control diet. The sum of SFA, MUFA and the n -6 /n -3 PUFA ratio were decreased by L. digitata , regardless the addition of exogenous enzymes. β-carotene was enhanced by L. digitata , individually or combined with CAZymes, being also responsible for a positive increase in total pigments. Macrominerals, in particular phosphorous and sulphur, were increased in the liver of broilers fed L. digitata individually relative to the control. For microminerals, copper, iron and the correspondent sum were consistently elevated in the liver of broilers fed L. digitata , individually or combined with exogenous CAZymes. The powerful discriminant analysis tool based on the hepatic characterization revealed a good separation between the control group and L. digitata diets but failed to discriminate the addition of feed enzymes.
Conclusions
Overall, this study highlights the value of L. digitata as a feed ingredient for the poultry industry. Moreover, we can conclude that the effect of L. digitata overpowers the effect of feed enzymes, both the Rovabio® Excel AP and the alginate lyase. Having in mind the negative effects observed on birds’ performance, our main recommendation at this stage is to restraint L. digitata incorporation level in forthcoming nutritional studies.
... These studies foster the concept that extracellular antioxidant coating is probably a novel strategy for the management of diabetes. In supporting this concept, extracellular superoxide dismutase (EcSOD) has an important role in protecting against diabetes-related oxidative stress [51,52] and in improving diabetic complications such as albuminuria [53], nephropathy [54], cardiovascular disease [55], and retinopathy [56]. Like EGCG, the >50 kDa fraction also exhibits antioxidant traits. ...
The present study investigated the influence of epigallocatechin-3-gallate (EGCG) and its autoxidation products on insulin sensitivity in db/db mice. Compared to EGCG, autoxidation products of EGCG alleviated diabetic symptoms by suppressing the deleterious renal axis of the renin-angiotensin system (RAS), activating the beneficial hepatic axis of RAS, and downregulating hepatic and renal SELENOP and TXNIP. A molecular weight fraction study demonstrated that polymeric oxidation products were of essential importance. The mechanism of action involved coating polymeric oxidation products on the cell surface to protect against cholesterol loading, which induces abnormal RAS. Moreover, polymeric oxidation products could regulate RAS and SELENOP at doses that were far below cytotoxicity. The proof-of-principal demonstrations of EGCG-derived polymeric oxidation products open a new avenue for discovering highly active polymeric oxidation products based on the oxidation of naturally occurring polyphenols to manage diabetes and other diseases involving abnormal RAS.
... Данный фермент, кодируемый геном Sod1, участвует в системе детоксикации супероксидных радикалов и обеспечивает защиту от окислительного стресса. Изменения активности SOD1 и экспрессии кодирующего ее гена были выявлены при различных заболеваниях, сопровождающихся активацией свободнорадикальных процессов [8,9]. Считается, что такие антиоксидантные ферменты, как супероксиддисмутаза, принимающие непосредственное участие в детоксикации активных форм кислорода, необходимы для выживания клеток [10]. ...
The aim of the study was to study the effect of hepatoprotective drugs on the expression of the Sod1 gene in rats with ethanol liver damage.
Materials and methods . Male outbred white rats were used in the experiment. Five groups of animals were formed, 14 individuals each. Distilled water was administered to rats of the 1st group (control); Group 2 — ethanol at a dose of 5 g/kg of body weight; Group 3 — ethanol and heptor at a dose of 72 mg/kg; Group 4 — ethanol and mexidol at a dose of 50 mg/kg; Group 5 — ethanol and OMU at a dose of 50 mg/kg. The drugs were administered 1 hour before the introduction of ethanol. 24 and 72 hours after the introduction of ethanol (7 individuals), the animals were decapitated and the liver was removed. The expression level of the Sod1 gene was assessed using real-time reverse transcription PCR.
Results . The fold change in Sod1 expression in rat liver after 24 h practically did not change in response to the introduction of ethanol to the animals. A tendency to a slight decrease was observed in relation to changes in the expression of Sod1 with the use of heptor and mexidol, while under the influence of OMU, the expression level increased moderately. After 72 h, the exposure to ethanol was accompanied by a slight decrease in the frequency of expression of the Sod1 gene. A similar trend was observed with respect to changes in Sod1 expression with the use of heptor, mexidol, and OMU.
Conclusion . The results obtained indicate that the introduction of both ethanol and the prophylactic use of hepatoprotective drugs did not lead to significant changes in the level of Sod1 gene expression in rat liver. Additional studies are needed to identify the mechanisms of regulation of the antioxidant system, as well as the search for drugs that affect the transcriptional activity of genes.
... In the arousal dynamics, ecto-SOD Akita et al., 2007), on the one hand, and RBC SOD, on the other hand, maintain Frontiers in Physiology | www.frontiersin.org 11 October 2021 | Volume 12 | Article 730657 the vascular NO level by removing O 2 •and thus play an important role in maintaining the requisite vascular tone and blood pressure (Fukai, 2002). It is noteworthy that during the arousal of ground squirrels, the plasma NO level steadily increases, however this increase becomes particularly significant upon reaching the Tb 25°C ( Figure 3B). ...
The hibernation of small mammals is characterized by long torpor bouts alternating with short periods of arousal. During arousal, due to a significant increase in oxygen consumption, tissue perfusion, and the launch of thermogenesis in cells, a large amount of reactive oxygen species (ROS) and nitrogen (RNS) can be formed, which can trigger oxidative stress in cells. To estimate this possibility, we studied the intensity of free-radical processes in the red blood cells (RBCs) of little ground squirrels (LGS; Spermophilus pygmaeus) in the dynamics of arousal from hibernation. We found that in the torpid state, the degree of generation of ROS and RNS (8.3%, p>0.09; 20.7%, p<0.001, respectively), the degree of oxidative modification of membrane lipids and RBC proteins is at a low level (47%, p<0.001; 82.7%, p<0.001, respectively) compared to the summer control. At the same time, the activity of superoxide dismutase (SOD) and catalase (CAT) in RBC is significantly reduced (32.8%, p<0.001; 22.2%, p<0.001, respectively), but not the level of glutathione (GSH). In the torpid state, SOD is activated by exogenous GSH in concentration-dependent manner, which indicates reversible enzyme inhibition. During the arousal of ground squirrels, when the body temperature reaches 25°C, RBCs are exposed oxidative stress. This is confirmed by the maximum increase in the level of uric acid (25.4%, p<0.001) in plasma, a marker of oxidative modification of lipids [thiobarbituric acid reactive substances (TBARS); 82%, p < 0.001] and proteins (carbonyl groups; 499%, p < 0.001) in RBC membranes, as well as the decrease in the level of GSH (19.7%, p < 0.001) in erythrocytes relative to the torpid state and activity of SOD and CAT in erythrocytes to values at the Tb 20°C. After full recovery of body temperature, the level of GSH increases, the ratio of SOD/CAT is restored, which significantly reduces the degree of oxidative damage of lipids and proteins of RBC membranes. Thus, the oxidative stress detected at Tb 25°C was transient and physiologically regulated.
... Nitric oxide is among the most important reactive nitrogen types. Vascular occlusions occur because of the decrease in NO bioactivity (Fukai et al., 2002). NO and oxygen radicals are extremely reactive and react rapidly to form nitrite, nitrate, and most importantly peroxynitrite anion (Singh et al., 2004). ...
The aim of this study was to investigate the effects of Lactobacillus farciminis on growth traits and antioxidant status in preweaning and postweaning Tuj lambs. Twenty lambs were divided into four groups, regardless of gender, with a mean live weight of 7.81 ± 0.50 kg. At the start of the experiment, the average age of the lambs was seven days. During the six-week preweaning period, control (C) lambs were fed with colostrum only, and Lactobacillus farciminis was given orally to the treated lambs at 1 g/day/lamb (L1), 2 g/day/lamb (L2) or 4 g/day/lamb (L3). The experiment continued for a total of 22 weeks. During the first six weeks, bodyweight (BW) increased significantly in L1 at the sixth week. Also during this period, bodyweight gain (BWG) in L2 at 2 - 3 weeks and in L3 at 5 - 6 weeks differed from C. In the subsequent period, BW and BWG were not affected by probiotic supplementation. The effects of probiotic supplementation on malondialdehyde (MDA), nitric oxide (NO), superoxide dismutase (SOD), glutathione peroxidase (GPx), and catalase (CAT) were significant throughout the experiment, with the effect on glutathione (GSH) also being important in the first six weeks. Thus, Lactobacillus farciminis provided orally to Tuj breed lambs could be used to improve their antioxidant status without compromising growth.
... The low level of SOD as observed in this study agrees with previous findings [59,60,61,62]. Various studies had shown association between reduction in SOD level and diabetic complications like diabetic foot ulcer [63], nephropathy [64], albuminuria [65] and cardiovascular diseases [66]. Therefore, improving SOD level may be a promising target in reducing oxidative stress and its related diabetic complications [67]. ...
Cellular damage due to oxidative stress had been implicated in the pathogenesis of many diseases including diabetes mellitus. This study was to investigate possible amelioration of oxidative stress in diabetes mellitus by aqueous leaf extract of Terminalia catappa. Wistar rats weighing 200 -250g was divided into nine groups with 6 rats per group. The main test group has 5 groups while the group for assessing possible mechanism had 4 groups. Group 1 (control) and group 2(non-diabetic) received orally per kg body weight; 0.5ml distilled water and 130mg of Terminalia catappa respectively. Group 3 (diabetic), group 4 (diabetic + extract) and group 5 (diabetic + insulin) also respectively received 0.5ml distilled water, 130mg Terminalia. catappa extract and 0.75UI insulin subcutaneously. Groups 6, 7, 8 and 9 administered orally with aspirin; 30mg/kg, meloxicam; 2mg/kg and combination of extract with aspirin and meloxicam respectively. The experiment lasted for 14 days and glucose level ≥ 200mg/dl was considered diabetic following intraperitoneal injection of 150mg/kg body weight of alloxan. Results showed significant (p<0.05) increase in serum low density lipoprotein cholesterol (LDL-c), malondialdehyde (MDA) and a significant (p<0.05) decrease in superoxide dismutase (SOD) in diabetic group compared with control. The LDL and MDA were significantly (p<0.05) reduced while SOD increased significantly (p<0.05) when compared with diabetic group and the control following administration of Terminalia catappa, aspirin, meloxicam and insulin. The leaf extract of Terminalia catappa possess possible ameliorating potential on oxidative stress induced damages by impeding lipid peroxidation but improved on antioxidant enzyme in diabetic condition.
... The increase of antioxidant enzymes in response to high ROS concentrations might be a compensatory response during early-stages of obesity development, in order to maintain the oxidative balance until the antioxidant capacity is depleted [57]. A sustained increase in the endogenous activity of antioxidant enzymes can reduce the incidence of oxidative stress and associated metabolic disorders by regulating ROS production [62,63]. For instance, antioxidant treatment improves insulin function in people living with diabetes [64]. ...
Adipose tissue (AT) storage capacity is central in the maintenance of whole-body homeostasis, especially in obesity states. However, sustained nutrients overflow may dysregulate this function resulting in adipocytes hypertrophy, AT hypoxia, inflammation and oxidative stress. Systemic inflammation may also contribute to the disruption of AT redox equilibrium. AT and systemic oxidative stress have been involved in the development of obesity-associated insulin resistance (IR) and type 2 diabetes (T2D) through several mechanisms. Interestingly, fat accumulation, body fat distribution and the degree of how adiposity translates into cardio-metabolic diseases differ between ethnicities. Populations of African ancestry have a higher prevalence of obesity and higher T2D risk than populations of European ancestry, mainly driven by higher rates among African women. Considering the reported ethnic-specific differences in AT distribution and function and higher levels of systemic oxidative stress markers, oxidative stress is a potential contributor to the higher susceptibility for metabolic diseases in African women. This review summarizes existing evidence supporting this hypothesis while acknowledging a lack of data on AT oxidative stress in relation to IR in Africans, and the potential influence of other ethnicity-related modulators (e.g., genetic-environment interplay, socioeconomic factors) for consideration in future studies with different ethnicities.
... SOD2 and SOD3 represent two out of three members of the SOD family and are the most important line of antioxidant defense systems against ROS. 56 In our case, we hypothesized that more ROS could be generated by the coexistence of both OA and T2DM diseases when compared to OA/T2DM − patients, which might be caused by a lower expression of both SOD2 and SOD3 in OA/T2DM + patients. In addition to cellular oxidative stress pathways, ECM-related pathways have been found enriched in the OA/T2DM − group. ...
Osteoarthritis (OA) is a multifactorial pathology and comprises a wide range of distinct phenotypes. In this context, the characterization of the different molecular profiles associated with each phenotype can improve the classification of OA. In particular, OA can coexist with type 2 diabetes mellitus (T2DM). This study investigates lipidomic and proteomic differences between human OA/T2DM– and OA/T2DM⁺ cartilage through a multimodal mass spectrometry approach. Human cartilage samples were obtained after total knee replacement from OA/T2DM– and OA/T2DM⁺ patients. Label-free proteomics was employed to study differences in protein abundance and matrix-assisted laser desorption/ionization (MALDI) mass spectrometry imaging (MSI) for spatially resolved-lipid analysis. Label-free proteomic analysis showed differences between OA/T2DM– and OA/T2DM⁺ phenotypes in several metabolic pathways such as lipid regulation. Interestingly, phospholipase A2 protein was found increased within the OA/T2DM⁺ cohort. In addition, MALDI-MSI experiments revealed that phosphatidylcholine and sphingomyelin species were characteristic of the OA/T2DM– group, whereas lysolipids were more characteristic of the OA/T2DM⁺ phenotype. The data also pointed out differences in phospholipid content between superficial and deep layers of the cartilage. Our study shows distinctively different lipid and protein profiles between OA/T2DM– and OA/T2DM⁺ human cartilage, demonstrating the importance of subclassification of the OA disease for better personalized treatments.
... Mammals express three SODs isoforms: the cytoplasmic copper/zinc-dependent SOD (SOD1; Cu/ZnSOD is a 32 kDa homodimeric enzyme), the mitochondrial manganese-dependent SOD (SOD2; MnSOD is an 88 kDa homotetrameric enzyme), and the extracellular Cu/ZnSOD (SOD3; is also dependent upon copper and zinc, contains a signaling peptide sequence, and exists as a homotetramer of 135 kDa) [25,26]. Several studies have reported a relationship between SOD3 and pathological conditions that involve vascular dysfunction, such as diabetes and cardiovascular disease [26,27]. ...
Vascular diseases are major causes of death worldwide, causing pathologies including diabetes, atherosclerosis, and chronic obstructive pulmonary disease (COPD). Exposure of the vascular system to a variety of stressors and inducers has been implicated in the development of various human diseases, including chronic inflammatory diseases. In the vascular wall, antioxidant enzymes form the first line of defense against oxidative stress. Recently, extensive research into the beneficial effects of phytochemicals has been conducted; phytochemicals are found in commonly used spices, fruits, and herbs, and are used to prevent various pathologic conditions, including vascular diseases. The present review aims to highlight the effects of dietary phytochemicals role on antioxidant enzymes in vascular diseases.
... Meals with higher glycemic index induce greater inflammatory response compared to meals with lower glycemic index (Muñoz and Costa, 2013). Also in this context, postprandial hypertriglyceridemia would trigger a transient pro-inflammatory state with higher production of IL-6 and IL-8, both responsible for stimulating the production of reactive oxygen species by leukocytes, thereby favoring OS (Fukai et al., 2002;Mc Clean et al., 2007). Wallace et al. (2010) showed a significant positive correlation between lipemia and production of free radicals, leukocyte superoxide anion, nitrotyrosine, TBARS and PGF-2α. ...
Oxidative stress (OS) has been strongly associated with postprandial lipemia (PPL) in humans, and still requires further investigation in dogs. However, since lipemia interferes with spectrophotometric determinations such as those used to assess OS, the present study investigated the effect of PPL on OS parameters of healthy dogs. Twenty dogs had lipemic postprandial samples compared to the average of two non-lipemic moments. Subsequently, PPL was simulated in vitro using a commercial lipid emulsion and twelve pools of non-lipemic serum of these dogs were used to simulate the minimum, median and maximum concentrations of triglycerides obtained during the lipemic state. Serum OS parameters were assessed using the antioxidants uric acid, albumin and total bilirubin; total antioxidant capacity (TAC); total oxidant capacity (TOC); and lipid peroxidation. In vivo PPL caused an increase in albumin, TAC-CUPRAC, TAC-FRAP, uric acid (p < 0.0001), TOC (p = 0.0012) and total bilirubin (p = 0.0245); reduction of TAC-ABTS (p = 0.0008); and did not alter the lipid peroxidation (p = 0.8983). In vitro, levels of albumin increased at the three lipemic concentrations (p < 0.0001), uric acid increased in the median and maximum levels (p < 0.0001), and total bilirubin concentration increased only at the maximum lipemic level (p = 0.0012). All lipemic levels tested increased TAC-ABTS (p = 0.0011) and TAC-FRAP (p < 0.0001). TAC-CUPRAC (p = 0.5002), TOC (p = 0.5938) and lipid peroxidation (p = 0.4235) were not affected by in vitro lipemia. In conclusion, both the in vivo postprandial state and in vitro simulated lipemia affect oxidative stress markers in dogs depending on the oxidative stress marker, and thus the postprandial state and/or lipemic samples should be avoided.
... Copyright © 2015 by the authors; licensee MDPI, Basel, Switzerland. detoxify superoxide anion radicals [28] and impaired vascular function or even lethality in SOD knockout mice [22,29,30]. Superoxide and related or reactive oxygen species (ROS) products (e.g. ...
Global epidemiological studies reported a shift from maternal/infectious communicable diseases to chronic non-communicable diseases and a major part is attributable to atherosclerosis and metabolic disorders. Accordingly, ischemic heart disease was identified as a leading risk factor for global mortality and morbidity with a prevalence of 128 million people. Almost 9 million premature deaths can be attributed to ischemic heart disease and subsequent acute myocardial infarction and heart failure, also representing a substantial socioeconomic burden. As evidenced by typical oxidative stress markers such as lipid peroxidation products or oxidized DNA/RNA bases, the formation of reactive oxygen species by various sources (NADPH oxidases, xanthine oxidase and mitochondrial resperatory chain) plays a central role for the severity of ischemia/reperfusion damage. The underlying mechanisms comprise direct oxidative damage but also adverse redox-regulation of kinase and calcium signaling, inflammation and cardiac remodeling among others. These processes and the role of reactive oxygen species are discussed in the present review. We also present and discuss potential targets for redox-based therapies that are either already established in the clinics (e.g. guanylyl cyclase activators and stimulators) or at least successfully tested in preclinical models of myocardial infarction and heart failure (mitochondria-targeted antioxidants). However, reactive oxygen species have not only detrimental effects but are also involved in essential cellular signaling and may even act protective as seen by ischemic pre- and post-conditioning or eustress – which makes redox therapy quite challenging.
... Vascular oxidative stress has broad effects on blood vessel function, and is central to the onset and progression of many cardiovascular diseases (74). ROS are also inducers of tumor angiogenesis via the generation of oxidized lipids and the induction of the HIF-1a/VEGF-A pathway in EC and VSMC (75). ...
Tumor-infiltrating lymphocytes (TILs) are major players in the immune-mediated control of cancer and the response to immunotherapy. In primary cancers, however, TILs are commonly absent, suggesting T-cell entry into the tumor microenvironment (TME) to be selectively restricted. Blood and lymph vessels are the first barriers that circulating T-cells must cross to reach the tumor parenchyma. Certainly, the crossing of the endothelial cell (EC) basement membrane (EC-BM)-an extracellular matrix underlying EC-is a limiting step in T-cell diapedesis. This review highlights new data suggesting the antioxidant enzyme superoxide dismutase-3 (SOD3) to be a regulator of EC-BM composition in the tumor vasculature. In the EC, SOD3 induces vascular normalization and endows the EC-BM with the capacity for the extravasation of effector T-cells into the TME, which it achieves via the WNT signaling pathway. However, when activated in tumor cells, this same pathway is reported to exclude TILs. SOD3 also regulates TIL density in primary human colorectal cancers (CRC), thus affecting the relapse rate and patient survival.
... This equilibrium is a part of a process that protects tissue damage versus oxidative stress. [6,30] Therefore, imbalance between oxidative reagents and antioxidants is unfavorable condition to maintain right cellular function. This phenomenon can lead to blood pressure increment and heart remodeling. ...
Background:
Aerobic exercises induce adaptations that improve physiological function. However, aerobic exercises, oxidative reproduction may lead to injury and other health issues such as adverse cardiac effects. The aim of this study is to evaluate the effect of aerobic exercises on protein expression change in the heart left ventricle to determine the advantages and disadvantages related to this mode of exercise.
Methods:
Male Wistar rats were randomized into two groups; trained (T) and control (C). Animals from T group were trained for 8 weeks, and then 2D LC-MS/MS iTRAQ method was used for extracting and analyzing the left ventricular proteins. Certain proteins that were highlighted in the special process were selected for further analysis via protein-protein interaction network (PPI) method. The identified proteins were enriched via gene ontology (GO) to find biological terms.
Results:
We identify five overexpressed antioxidant proteins in T group compared with C group including extracellular superoxide dismutase [Cu-Zn], Frataxin, protein kinase C delta type, STE20/SPS1-related proline-alanine-rich protein kinase, and amyloid-beta A4 protein.
Conclusions:
Findings indicate that catalase and insulin are two exercise-related proteins. However, they were not included in the significant differentially expressed proteins. Finally it was found that enhancement of antioxidative activity is a direct effect of aerobic exercises.
... Free radicals have also been implicated in congestive heart failure, the annual incidence of which is one to five per 1000 person, and the relative incidence doubles for each decade of life after the age of 45. Experimental evidence suggests a direct link between free radical production and CHF [9,10], and the presence of ROS in circulating blood is also the key intermediary related to vascular injury and organ dysfunction [10][11][12]. The use of nanoscale materials is growing exponentially as concerns rise about the human hazards to it. ...
Background: Cyclophosphamide (CP) is used for the treatment of ovarian cancer, breast cancer, chronic lymphocytic leukemia, non-Hodgkin’s lymphoma, neuroblastoma, soft tissue sarcoma, rhabdomyosarcoma, and Wilms’ tumor. It causes dyslipidemia in experimental animals. Zinc oxide is the most widely used nanoparticles among various nanomaterials. Zinc oxide nanoparticles were ameliorated hepatotoxicity, hematotoxicity oxidative stress, and disturbance in the antioxidant defense system induced by cyclophosphamide in experimental animals.
Objectives: The present study aimed to evaluate the anti-dyslipidemic effect of zinc oxide nanoparticles against cyclophosphamide-induced by dyslipidemia in male albino rats.
Materials and Methods: Twenty-four adult male rats (Sprague Dawley) were grouped randomly into four groups of six rats each. Group I. Control group: Received 0.2 ml saline /day i.p. injection for 14 days (day by day), group II (nZnO group): Received nZnO (5 mg/kg) /day b.w., intraperitoneally for 14 days, Group III (CP group): Received CP 20 mg/kg/day body weight (b.w.) day by day for 14 days by intraperitoneal injection, Group IV
(CP + ZnO NPs group): Received nZnO group: Received nZnO (5 mg/kg/day) b.w., intraperitoneally for 14 days, plus CP 20 mg/kg/day body weight (b.w.) day by day for 14 days by intraperitoneal injection. At the end of the experimental period, rats were anesthetized using light ether. Blood samples were taken and prepared for biochemical measurements.
Results: Administration of CP to rats resulted in a significant increase (p<0.05) in the levels of serum total cholesterol, triglycerides, and LDL cholesterol and a significant decrease (p<0.05) in serum HDL-cholesterol, as compared to control group. Conversely, the groups treated with nZnO showed a significant decrease (p<0.05) in serum total cholesterol, triglycerides, and LDL-cholesterol and a significant increase (p<0.05) in serum HDL-cholesterol, as compared to CP group.
Conclusion: It can be concluded that exposure of rats to CP induced dyslipidemia and treatment of rats with zinc oxide nano-particles and CP together prevented dyslipidemia induced by CP. These results may provide further visions into the proper treatment of patients by improving the side effects of chemotherapy. However further studies are necessary to establish optimal doses of nZnO and receive the best safety profile.
Keywords: Zinc oxide nanoparticles, Anti-dyslipidemia, Anti-hyperlipidemia, Cyclophosphamide, Lipid profile, Albino rats.
... Mn SOD (SOD2) contains manganese and it is predominantly found in the mitochondrial matrix (27). The third one, Cu/Zn extracellular SOD (SOD3), also contains copper and zinc and is secreted in the extracellular space (28). Superoxide radical anions are unstable molecules, commonly produced by aerobic metabolism. ...
Superoxide dismutase is widespread in the human body, including skin and its appendages. Here, we focus on human skin copper/zinc superoxide dismutase, the enzyme that protects skin and its appendages against reactive oxygen species. Human skin copper/zinc superoxide dismutase resides in the cytoplasm of keratinocytes, where up to 90% of cellular reactive oxygen species is produced. Factors other than cell type, such as gender, age and diseased state influence its location in skin tissues. We review current knowledge of skin copper/zinc superoxide dismutase including recent studies in an attempt to contribute to solving the question of its remaining unexplained functions. The research described here may be applicable to pathologies associated with oxidative stress. However, recent studies on copper/zinc superoxide dismutase in yeast reveal that its predominant function may be in signaling pathways rather than in scavenging superoxide ions. If confirmed in the skin, novel approaches might be developed to unravel the enzyme's remaining mysteries.
... 3 Superoxide dismutase (SOD) is an antioxidant enzyme, involved in the catabolism of the superoxide anion. [4][5][6] A particularly important pathophysiological event related to ROS is oxidation of lipids, in particular of low-density lipoprotein (LDL), 7 a process that is central to atherosclerotic lesion formation. ...
Cardiovascular disease (CVD), one of the main mortality causes worldwide is considered to be affected by general oxidative stress and inadequacy antioxidant system. Superoxide dismutase 1 (SOD1), a cytosolic antioxidant enzyme has a key role in neutralizing the excessive prooxidant by scavenging the super oxide anions. SOD1 polymorphic variants exhibit the altered activity properties. In the current study, we are aimed to investigate the association between the SOD1 polymorphism and CVD prevalence. A 6‐years case control follow up study was designed to genotype the 526 participants (311 controls and 215 cases) for studying the 50 bp INS/DEL polymorphism at SOD1 promoter gene and analyze their blood lipid profile and anthropometric characteristics. Among the two possible alleles of the SOD1 gene (Wild [W] and Mutant [M]) the meaningful association was detected between the Mutants’ frequency and the prevalence of CVD patients (p‐value <.001). The W and M allele refer to inserted and deleted 50 bp in the polymorphic site of the SOD1 promoter, respectively. The WM and MM genotypes' frequency which indicate the wild heterozygotes and Mutant homozygotes, respectively, were significantly correlated with the prevalence of cardiovascular disease (p‐value <.001). The present study has the potential to introduce the 50 bp INS/DEL polymorphism of SOD1 genotyping as a novel unique diagnostic approach for screening the high risk CVD.
... The superoxide radical anion (O 2 • − ) can be formed from different sources such as xanthine oxidase, NADPH (nicotinamide adenine dinucleotide phosphate) oxidases, uncoupled NO synthases and the mitochondrial respiratory chain, and represent in many ways a direct antagonist of nitric oxide as shown by the famous experiment by Gryglewski et al. [12]. The existence of superoxide dismutases (mitochondrial MnSOD and cytosolic/extracellular Cu, Zn-SOD) implies that superoxide may be harmful for the cell [13], which is supported by the fact that deficiency in MnSOD is lethal [14,15] and deficiency in Cu, Zn-SOD renders mice susceptible to cardiovascular and neuronal complications [16][17][18]. ...
Background:
Reactive oxygen and nitrogen species (RONS such as H2O2, nitric oxide) are generated within the organism. Whereas physiological formation rates confer redox regulation of essential cellular functions and provide the basis for adaptive stress responses, their excessive formation contributes to impaired cellular function or even cell death, organ dysfunction and severe disease phenotypes of the entire organism. Therefore, quantification of RONS formation and knowledge of their tissue/cell/compartment-specific distribution is of great biological and clinical importance.
Methods:
Here, we used a high-performance/pressure liquid chromatography (HPLC) assay to quantify the superoxide-specific oxidation product of the mitochondria-targeted fluorescence dye triphenylphosphonium-linked hydroethidium (mitoSOX) in biochemical systems and three animal models with established oxidative stress. Type 1 diabetes (single injection of streptozotocin), hypertension (infusion of angiotensin-II for 7 days) and nitrate tolerance (infusion of nitroglycerin for 4 days) was induced in male Wistar rats.
Results:
The usefulness of mitoSOX/HPLC for quantification of mitochondrial superoxide was confirmed by xanthine oxidase activity as well as isolated stimulated rat heart mitochondria in the presence or absence of superoxide scavengers. Vascular function was assessed by isometric tension methodology and was impaired in the rat models of oxidative stress. Vascular dysfunction correlated with increased mitoSOX oxidation but also classical RONS detection assays as well as typical markers of oxidative stress.
Conclusion:
mitoSOX/HPLC represents a valid method for detection of mitochondrial superoxide formation in tissues of different animal disease models and correlates well with functional parameters and other markers of oxidative stress.
... Diabetic cardiovascular diseases ROS induces oxidation of lipids especially low-density lipoproteins (LDL), which are important for the development of atherosclerotic lesion formation [19]. Hence, oxidative stress is considered a causative agent in the pathogenesis of several cardiovascular diseases such as atherosclerosis, hypertension, and diabetes. ...
Free radicals and other oxidants are critical determinants of the cellular signaling pathways involved in the pathogenesis of several human diseases including inflammatory diseases. Numerous studies have demonstrated the protective effects of antioxidant enzymes during inflammation by elimination of free radicals. The superoxide dismutase (SOD), an antioxidant enzyme, plays an essential pathogenic role in the inflammatory diseases by not only catalyzing the conversion of the superoxide to hydrogen peroxide and oxygen but also affecting immune responses. There are three distinct isoforms of SOD, which distribute in different cellular compartments such as cytosolic SOD1, mitochondrial SOD2, and extracellular SOD3. Many studies have investigated the anti-oxidative effects of SOD3 in the inflammatory diseases. Herein, in this review, we focus on the current understanding of SOD3 as a therapeutic protein in inflammatory diseases such as skin, autoimmune, lung, and cardiovascular inflammatory diseases. Moreover, the mechanism(s) by which SOD3 modulates immune responses and signal initiation in the pathogenesis of the diseases will be further discussed.
... SOD3, or extracellular superoxide dismutase EcSOD, is localized in the extracellular matrix and binds to the glycocalyx in cell surfaces [54]. SOD3 functions neutralize from O 2 • − by the membrane-bound NOXs to H 2 O 2 [54][55][56]. The role of SOD3 in cancer is less known. ...
Cellular reactive oxygen species (ROS) status is stabilized by a balance of ROS generation and elimination called redox homeostasis. ROS is increased by activation of endoplasmic reticulum stress, nicotinamide adenine dinucleotide phosphate (NADPH) oxidase family members and adenosine triphosphate (ATP) synthesis of mitochondria. Increased ROS is detoxified by superoxide dismutase, catalase, and peroxiredoxins. ROS has a role as a secondary messenger in signal transduction. Cancer cells induce fluctuations of redox homeostasis by variation of ROS regulated machinery, leading to increased tumorigenesis and chemoresistance. Redox-mediated mechanisms of chemoresistance include endoplasmic reticulum stress-mediated autophagy, increased cell cycle progression, and increased conversion to metastasis or cancer stem-like cells. This review discusses changes of the redox state in tumorigenesis and redox-mediated mechanisms involved in tolerance to chemotherapeutic drugs in cancer.
PURPOSE: The purpose of this study was to characterize the associations between inflammatory and oxidative stress biomarkers, demographic, polysomnographic and spirometric parameters in patients with suspected obstructive sleep apnea (OSA) and/or obstructive airway disease.
METHODS: This was a cross-sectional exploratory study of patients referred to the University of British Columbia Sleep Clinic who had a diagnostic polysomnogram for suspected OSA. All patients had samples collected for measurements of IL-10, IL-6, e-selectin, endostatin, VCAM-1, ICAM-1, PDGF, thrombospondin-2, 8-OHdG, 8-isoprostane and superoxide dismutase. Spearman correlation and multiple linear regression were used to identify predictors of biomarkers.
RESULTS: A total of 63 patients were included: 65% male, mean age 53 years and body mass index (BMI) 33 kg/m². Inflammatory biomarkers were associated with female sex (IL-6, coefficient 0.51, p = 0.032), FEV1 (IL-6, coefficient −0.02, p = 0.013) and BMI (VCAM-1, coefficient 0.009, p = 0.051). The oxidative stress marker, 8-OHdG, was associated with hypoxemia in rapid eye movement (REM) sleep (coefficient 0.006, p = 0.02). Age and BMI were both independently associated with percentage of time spent below SpO2 90%. REM sleep and patients with overlap conditions and OSA had greater degree of REM and nonrapid eye movement (NREM) sleep hypoxemia than control group. Lastly, there were no differences in oxidative or inflammatory biomarkers between control, OSA, obstructive airway disease and overlap groups though the number of patients in each group were small.
CONCLUSION: Female sex, lower FEV1 and increased BMI were independent predictors of increased inflammatory biomarker levels. The oxidative stress marker 8-OHdG was associated with hypoxemia indices of REM. Larger studies are warranted to delineate biomarker profiles in patients with overlap conditions.
Alzheimer's disease (AD) is a progressive neurodegenerative disorder of the brain that leads to irreversible loss of neurons with age, resulting in severe memory loss and cognitive dysfunctions. Currently, AD can neither be prevented nor cured. It is estimated that as on today 26.6 million suffer worldwide and in future, Alzheimer's is predicted to affect 1 in 85 people globally by 2050. Major AD pathological indices are formation of brain: Senile Plaques (SP), Neurofibrillary Tangles, Cholinergic neuronal Loss (Synapse loss) and neurodegeneration. Oxidative stress and Amyloid β-peptide [Aβ] deposition are hallmarks of AD. In the present study, D-Galactose is used to induce AD, since it was already reported that D-galactose, is a normal metabolic substance, when exceeds the normal levels will produce Reactive Oxygen Species (ROS), enhances Advanced Glycation End-products (AGE) through oxidative metabolism and accelerates formation of oxidative lesions in brain, finally leading to AD.
Superoxide dismutase (SOD) is one of the most abundant antioxidant enzymes in aerobic organisms as it neutralizes superoxide radicals (O2•−) and protects against oxidative stress. In both prokaryotes and eukaryotes, this enzyme has evolved separately in different forms - Cu/Zn-SOD, Mn-SOD, Fe-SOD, and Ni-SOD, based on the metal cofactors attached to their active sites. These metals are involved in the transition of electronic charges during the catalysis of the O2•− dismutation reaction. SODs have shown their therapeutic potential against reactive oxygen species-mediated diseases in many in vitro and in vivo studies as well as in clinical trials. As SOD administration has certain limitations due to their low half-life, use SOD mimetics have been very promising in this case. However, excess of SOD in circulation due to overexpression or over administration can be detrimental for the body, which reveals that this antioxidant has a dark side as well.
Cardiovascular diseases remain the leading cause of death in recent decades worldwide, especially in developed countries. Cardiovascular pathology can begin with risk factors that can cause local vascular damage and end with systemic complications leading to organ failure and death, which makes it necessary to understand the biochemistry of events associated with the entire process of progression of cardiovascular diseases and is crucial for diagnosis, prevention and treatment. It is known that the state of blood vessels is influenced by multiple factors of hemodynamic conditions, extracellular signaling proteins, including interleukins, cytokines, and intracellular biochemical molecules, including reactive oxygen and nitrogen species. The aim of the work was to evaluate the factors of oxidative stress and antioxidant protection in patients with coronary heart disease. The study included 96 patients of working age with a verified diagnosis of coronary artery disease. Statistical analysis was carried out using the StatTech v. 2.6.5. To assess the diagnostic significance of quantitative signs in predicting a certain outcome, the method of analyzing ROC curves was used. The article presents data on the quantitative content of nitric oxide, myeloperoxidase, superoxide dismutase in the blood serum of patients with coronary heart disease (acute myocardial infarction and unstable angina pectoris), describes the relationship between changes in their level, and assesses the diagnostic significance of the studied parameters. The obtained data on the production of nitric oxide, myeloperoxidase and superoxide dismutase in patients with acute myocardial infarction and unstable angina indicate an important prognostic value of assessing oxidative stress and the antioxidant system for early risk stratification of adverse outcomes in patients with coronary heart disease.
Fluorophores with aggregation-induced emission (AIE) are characterized by many advantageous features for biomedical applications, including excellent photostability and enhanced fluorescent emission in aqueous milieu with minimal aggregation caused quenching (ACQ) effect. The abnormal levels of biomarkers are closely correlated with various diseases. Hence developing new strategies for detection and imaging of disease biomarkers fluorescently and optoacoustically is of high significance for early diagnosis of diseases. Probes (contrast agents) play essential roles in fluorescent and optoacoustic imaging. They have been extensively explored and applied in recent years, which induce the emergence of a variety of new probes in particular the biomarker-activatable probes based on smart AIEgens for fluorescence and optoacoustic imaging. In this review, we aim to summarize the latest development and progress as well as biomedical applications of the biomarker-activatable probes based on smart AIEgens. We focus on their design strategies and highlight the prospects and challenges in fluorescent and optoacoustic imaging.
Snake envenomation is a common but neglected disease that affects millions of people around the world annually. Among venomous snake species in Brazil, the tropical rattlesnake (Crotalus durissus terrificus) accounts for the highest number of fatal envenomations and is responsible for the second highest number of bites. Snake venoms are complex secretions which, upon injection, trigger diverse physiological effects that can cause significant injury or death. The components of C. d. terrificus venom exhibit neurotoxic, myotoxic, hemotoxic, nephrotoxic, and cardiotoxic properties which present clinically as alteration of central nervous system function, motor paralysis, seizures, eyelid ptosis, ophthalmoplesia, blurred vision, coagulation disorders, rhabdomyolysis, myoglobinuria, and cardiorespiratory arrest. In this study, we focused on proteomic characterization of the cardiotoxic effects of C. d. terrificus venom in mouse models. We injected venom at half the lethal dose (LD50) into the gastrocnemius muscle. Mouse hearts were removed at set time points after venom injection (1 h, 6 h, 12 h, or 24 h) and subjected to trypsin digestion prior to high-resolution mass spectrometry. We analyzed the proteomic profiles of >1300 proteins and observed that several proteins showed noteworthy changes in their quantitative profiles, likely reflecting the toxic activity of venom components. Among the affected proteins were several associated with cellular deregulation and tissue damage. Changes in heart protein abundance offer insights into how they may work synergistically upon envenomation.
Significance
Venom of the tropical rattlesnake (Crotalus durissus terririficus) is known to be neurotoxic, myotoxic, nephrotoxic and cardiotoxic. Although there are several studies describing the biochemical effects of this venom, no work has yet described its proteomic effects in the cardiac tissue of mice. In this work, we describe the changes in several mouse cardiac proteins upon venom treatment. Our data shed new light on the clinical outcome of the envenomation by C. d. terrificus, as well as candidate proteins that could be investigated in efforts to improve current treatment approaches or in the development of novel therapeutic interventions in order to reduce mortality and morbidity resulting from envenomation.
Superoxide dismutases (SODs) are ancient enzymes of widespread importance present in all domains of life. Many insights have been gained into these important enzymes over the 50 years since their initial description, but recent studies in the context of microbial pathogenesis have resulted in findings that challenge long established dogmas. The repertoire of SODs that bacterial pathogens encode is diverse both in number and in metal dependencies, including copper, copper and zinc, manganese, iron, and cambialistic enzymes. Other bacteria also possess nickel dependent SODs. Compartmentalization of SODs only partially explains their diversity. The need for pathogens to maintain SOD activity across distinct hostile environments encountered during infection, including those limited for essential metals, is also a driver of repertoire diversity. SOD research using pathogenic microbes has also revealed the apparent biochemical ease with which metal specificity can change within the most common family of SODs. Collectively, these studies are revealing the dynamic nature of SOD evolution, both that of individual SOD enzymes that can change their metal specificity to adapt to fluctuating cellular metal availability, and of a cell's repertoire of SOD isozymes that can be differentially expressed to adapt to fluctuating environmental metal availability in a niche.
Pulmonary arterial hypertension is a progressive disorder characterized by remodeling and increased small pulmonary arteries resistance. Endothelin-1 (ET-1) was related to PAH and ET-1 receptors were up-regulated selectively in the lung when exposed to toxic factor hypoxia. However, the role of ET-1 signaling in the pathogenesis of prenatal hypoxia-induced pulmonary abnormalities remains to be elucidated. Pregnant rats were divided into prenatal hypoxia (10.5% O2 from gestational day 4-21) and control group. Their three-month-old offspring male rats were tested for vascular functions and molecular analysis, DNA methylation was assessed for cellular hypoxia. Functional testing showed that ET-1-mediated vasoconstriction was enhanced, and the expressions of endothelin A receptor/B receptor (ETAR/ETBR), inositol 1,4,5-trisphosphate receptor, type 1, and the sensitivity of calcium channels were increased in the small pulmonary arteries following prenatal hypoxia. q-PCR and DHE staining showed that the expressions of NADPH oxidase 1/4 (Nox1/4) were up-regulated, along with the increased production of superoxide anion. Furthermore, superoxide anion promoted ET-1-mediated pulmonary artery contraction. In the pulmonary artery smooth muscle cell experiments, q-PCR, Western Blot, CCK8 and DHE staining showed that the expressions of ETBR, Nox1/4, and superoxide anion were increased by hypoxia, along with promoted cell proliferation. 2,2,6,6-Tetramethyl-1-piperidinyloxy reversed hypoxia-induced cell proliferation. ETBR antagonist BQ788 inhibited hypoxia-increased expressions of Nox1/4, superoxide anion production, and proliferation of cells. Moreover, methylation analysis indicated that hypoxia decreased the methylation levels of the ETBR promoter in the pulmonary artery smooth muscle cells. The results indicated that prenatal toxic factor hypoxia resulted in abnormal ETBR activation, which enhanced ET-1-mediated vasoconstriction of pulmonary arteries and pulmonary artery smooth muscle cell proliferation through ETBR/Nox1/4-derived ROS pathway.
Each individual is made up of nearly 50,000 billion cells organized into tissues (connective tissue, epithelial tissue, nerve tissue, muscle tissue) that will themselves form organs (heart, brain, lung, skin ...). . Every day, within each organ, thousands of cells will multiply (by cell division) and others will die (by apoptosis). This constant renewal ensures the proper functioning of the organization. It is controlled by thousands of genes that act together to "order" cells to multiply or die depending on the situation.
Cancer is a disease that has to do with the body's cells. The body is made up of billions of cells. Normal cells grow and divide (split into two). When they die, they are replaced by new cells.
Sometimes, something goes wrong with some cells and they don't die. They divide out of control and may grow into a lump (tumour) called cancer.
When the mutations are too important to repair, the cell will be self-destructed by apoptosis. But sometimes, these security systems work poorly or no longer work: the cell will then continue to multiply despite the presence of unrepaired mutations. If the latter affect genes involved in the regulation of cell proliferation or apoptosis, the cell can quickly become uncontrollable and multiply in an anarchic manner, leading to tumor formation.
There are over 100 different types of cancer.
Cancer can happen to anybody. Nobody really knows what causes most cancers. Some things (called risk factors) may make it more likely to happen.
These include smoking, not getting enough exercise, drinking too much alcohol, not eating well and being overweight. Cancer may also develop because of family history or substances in our environment that affect our bodies, such as chemicals and asbestos.
Manganese in the diet is nutritionally essential for normal physiologic functioning. However, excessive exposure to manganese has been associated with developmental, neurodegenerative and other disorders.
The book comprehensively covers the toxicology of manganese. Leading investigators provide perspectives from toxicology, neuroscience, nutrition, molecular biology and risk assessment disciplines and chapters cover the toxicokinetics, toxicodynamic interactions and health effects of manganese, as well as its potential role in neurodegenerative diseases. A large section devoted to health effects presents the latest research that associates manganese exposure to potential human diseases.
Any scientists, health professional or regulator involved with metal exposure and toxicology should find this volume essential reading. Students and researchers in neurotoxicology will also find this book a useful reference.
A series of two new mono- and one binuclear µ-nitrato bridged copper(II) complexes [Cu(L)(HL)]ClO4 (1), [Cu(HL)(NO3)(H2O)]2NO3∙H2O (2) and [Cu2(L2)(µ-NO3)2] (3), with an unsymmetrical NNO donor Schiff base (HL) have been synthesized and characterized by elemental analysis, FTIR, CV, UV-vis and EPR spectroscopy. Their molecular structures were also determined by single crystal X-ray crystallography. In the binuclear complex 3, the Cu⋯ Cu distance is 3.494 Å. In 1, 2 and 3, the Cu(II) centers have distorted square pyramidal geometry (τ5 = 0.05 - 0.17). Evidence of weak π⋯π stacking intermolecular interactions along with other non-covalent interactions (hydrogen bonding) was observed by analyzing the respective crystal structures of the complexes. Thus, these hydrogen bonds, π⋯π stacking interactions and other weak intermolecular interactions establish in the form of supramolecular architectures a crystalline “network” environment. The non-covalent interactions were also investigated by employing Hirshfeld Analysis. The room temperature magnetic moments of the mononuclear complexes are less than the spin only values which are indicative of small interactions. Also, significant magnetic interactions were not exhibited by binuclear copper(II) complex 3 in the variable temperature magnetic measurements. The X-band EPR spectra of all three complexes exhibit copper(II) hyperfine structures as well as zero-field splitting which are appropriate for the triplet states of dimers. In complexes 1 and 2, the presence of pseudo dipolar interactions is proposed. Quantum chemical calculations (DFT) were carried out on complexes 1-3 to explore the electronic and spectral properties of these newly synthesized complexes. These complexes show significant antiproliferative and SOD activity. The SOD activity measured in terms of kMcCF is in the range 4.94 - 12.31 (mol L)⁻¹s⁻¹)× 10⁴.
Currently, there are not many in-depth studies focusing on the protein analysis of antioxidants involved in the calcification of the femoral artery. In this context, this study aimed to increase the knowledge of the molecular redox mechanisms involved in this process. Samples from calcified femoral artery sections of seven patients diagnosed with type 2 diabetes (T2D) and critical ischemia were analyzed. The isolated proteins were identified using liquid chromatography and mass–mass spectrometry and were used to generate a protein–protein interaction (PPI) network. Subsequently, highly interconnected regions within the PPI network were identified to obtain a representative module linked to oxidative stress. The proteins of this module with a higher degree of centrality (hubs) were selected to validate them by datamining, transcriptomic and proteomic assays. The analysis of modules of the femoral PPI network showed a module with mainly antioxidant function in which superoxide dismutase 2 (SOD2) was reported as the most important hub. SOD2 was validated at transcriptomic and proteomic level and confirmed by datamining. These results indicate that SOD activity is highly linked to the atherosclerotic process. We suggest that SOD2 could be a potential therapeutic target to prevent the calcification of the femoral artery. The maintenance of optimal SOD2 levels and its cofactors could be used as a preventive strategy for vascular calcification and the related cardiovascular complications in T2D patients.
Background
Endothelial dysfunction is common in patients undergoing hemodialysis (HD). However, little is known about the relationship between endothelial dysfunction and coenzyme Q10 (CoQ10) levels in HD patients.
Methods
Eligible HD patients were enrolled in this study according to prespecified inclusion and exclusion criteria. Endothelial function was assessed by brachial artery flow‐mediated dilation (FMD). Plasma CoQ10, serum malondialdehyde (MDA), and 8‐hydroxydeoxyguanosine (8‐OHdG) levels were measured. The potential confounders identified by univariate analyses (p < 0.15) were selected in a stepwise multiple regression model.
Results
In total, 111 HD patients were enrolled in this study. The mean CoQ10 level was 633.53 ± 168.66 ng/ml, and endothelial dysfunction was prevalent (91.0%) using a cut‐off value of 10% FMD. A significant correlation was observed between FMD and plasma CoQ10 level (r = 0.727, p < 0.001). After adjusting for potential parameters, a stepwise multivariate linear regression analysis revealed that CoQ10 level was an independent predictor of FMD (β = 0.018, p < 0.001). When CoQ10 was dichotomized using the median value (639.74 ng/ml), the conclusion remained unchanged (β = 0.584, p < 0.001). Pearson's correlation analyses revealed that plasma CoQ10 level was negatively correlated with MDA (r = −0.48, p < 0.001) and 8‐OHdG (r = −0.43, p < 0.001) levels.
Conclusions
Our data demonstrate that impaired brachial artery FMD was common in HD patients. CoQ10 level was independently associated with FMD, and oxidative stress may constitute a link between CoQ10 level and endothelial dysfunction in these patients.
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In this study, a metabolomic analysis was used to reveal the neurotoxicity of the CdTe/ZnS QDs via microglia polarization. A gas chromatography-mass spectrometer (GC-MS) was applied to uncover the metabonomic changes in microglia (BV-2 cell line) after exposure to 1.25 μM CdTe/ZnS QDs. 11 annotated metabolic pathways (KEGG database) were significantly changed in all exposed groups (3 h, 6 h, 12 h), 3 of them were related to glucose metabolism. The results of the Seahorse XFe96 Analyzer indicated that the CdTe/ZnS QDs increased the glycolysis level of microglia by 86% and inhibited the aerobic respiration level by 54% in a non-hypoxic environment. In vivo study, 3 h after the injection of CdTe/ZnS QDs (2.5 mM) through the tail vein in mice, the concentration of the CdTe/ZnS QDs in hippocampus reached the peak (1.25 μM). The polarization level of microglia (Iba-1 immunofluorescence) increased 2.7 times. In vitro study, the levels of the extracellular TNF-α, IL-1β and NO of BV-2 cells were all increased significantly after a 6 h or 12 h exposure. According to the results of the Cell Counting Kit-8, after a 6 h or 12 h exposure to the CdTe/ZnS QDs, the exposed microglia could significantly decrease the number of neurons (HT-22 cell line). This study proved that CdTe/ZnS QDs could polarize microglia in the brain and cause secondary inflammatory damage to neurons. There are potential risks in the application of the CdTe/ZnS QDs in brain tissue imaging.
Superoxide dismutase 3 (SOD3 or EC-SOD) is the only scavenger of superoxide in the extracellular space allowing for the catalyzed dismutation of the superoxide radical into hydrogen peroxide. The activity and distribution of the enzyme are regulated at several levels, suggesting the need for balanced activity in the extracellular space. The protein acts as an antioxidant by inhibiting reactions fueled by superoxide, including the reaction with nitric oxide, which generates peroxynitrite. However, the enzyme can also be categorized as a prooxidant providing hydrogen peroxide, which is known to control diverse redox-regulated processes by the oxidation of specific target proteins. The dual role of SOD3 as an antioxidant or prooxidant is central to fine-tuning the redox tone in the extracellular environment and warrants further investigations to fully understand the role of this protein in health and disease.
Accumulating evidence suggest that activation of proinflammatory M1 type macrophages in the synovium plays a vital role in the progression of osteoarthritis (OA). Redundant nitric oxide (NO) and hydrogen peroxide (H2O2) are key factors that drive macrophages to polarize to M1 type. Herein, modified zeolitic imidazolate framework-8 (ZIF-8) nanoparticles (NPs) have been synthesized. Via regulating intracellular gases and reprogramming metabolism phenotype, modified NPs transformed macrophages polarization from proinflammatory M1 to antiinflammatory M2 phenotype. Specifically, s-methylisothiourea hemisulfate salt (SMT) was loaded into ZIF-8 NPs to inhibit inducible nitric oxide synthase (iNOS), hence reducing NO production. Catalase (CAT) was encapsulated to catalyze the production of oxygen (O2) from H2O2. Results demonstrated that modified NPs were capable of catalyzing H2O2 to produce O2 and eliminate NO, hence inhibiting hypoxia-inducible factor 1α (HIF-1α) further rescuing mitochondrial function. Moreover, anti-CD16/32 antibody (Ab) modification could prolong the retention time of NPs in knee joints of OA mice with anterior cruciate ligament transection (ACLT). More significantly, modified NPs suppressed M1 macrophages and up-regulated M2 macrophages infiltration in the synovium, further inhibiting cartilage degeneration. This ZIF-8 NPs-based gas regulation and metabolic reprogramming strategy may pave a new avenue for OA treatment.
Eriocheir sinensis (E. sinensis) is an important aquaculture species in China. However, deteriorating water environments lead to oxidative stress in these crabs, which subsequently reduces their quality and yield. Glutathione (GSH) is an endogenous antioxidant that is used to mitigate oxidative stress. However, whether dietary GSH can enhance the resistance of E. sinensis to oxidative stress remains unclear. Herein, crabs were fed dietary GSH (the basal diet was supplemented with 0, 300, 600, 900, and 1200 mg/kg diet weight of GSH) for up to 3 weeks and, then, challenged with lipopolysaccharide (LPS; 400 μg/kg body weight). After 6 h, their hepatopancreas were sampled. Diet supplementation with 600 and 900 mg/kg diet weight GSH not only increased the content of GSH in the hepatopancreas, but also enhanced the activities and mRNA expressions of superoxide dismutase (SOD), glutathione peroxidase (GSH-Px), and glutathione-S-transferase (GST) (P < 0.05), compared to that in control crabs challenged with LPS alone. Diet supplementation with 600 or 900 mg/kg GSH also significantly increased the enzyme activities of GSH reductase and γ-glutamyl cysteine synthetase (γ-GCS) in LPS-treated crabs. Haematoxylin-eosin (HE) staining, electron microscopy, and flow cytometry were used to examine the structure and subcellular structure of and apoptosis in the hepatopancreas. The histopathology and sub-microstructure analysis results also showed that diet supplementation with 600 or 900 mg/kg GSH significantly alleviated damage in crabs challenged with LPS and decreased reactive oxygen species (ROS) levels and cell apoptosis ratios in the hepatopancreas, compared to the LPS-treated crabs. To further understand the effect of dietary GSH on LPS-induced apoptosis, the activities and gene or protein expression of apoptosis-related factors were evaluated. As a result, diet supplementation with 600 or 900 mg/kg GSH significantly decreased the activities of caspases-3, -8, and -9 and inhibited the relative expression of caspase-3 and -8 but increased the expression of B-cell lymphoma-2 (bcl-2) and B-cell lymphoma-2-associated X inhibitor (bax inhibitor) in crabs challenged with LPS. This treatment further significantly downregulated the relative protein levels of caspase-3, -8, -9 and Bax and upregulated those of Bcl-2 in crabs challenged with LPS. However, treatment with 1200 mg/kg GSH caused the opposite effects. Overall, our results reveal that appropriate diets supplemented with 600 or 900 mg/kg GSH could enhance the antioxidant capacity and anti-apoptotic mechanisms in crabs after LPS injection, thereby providing a theoretical basis for the application of dietary GSH in E. sinensis.
The influence of cytokines on extracellular superoxide dismutase (EC-SOD) expression by human dermal fibroblasts was investigated. The expression was markedly stimulated by interferon-gamma (IFN-gamma), was varying between fibroblast lines stimulated or depressed by interleukin-1 alpha (IL-1 alpha), was intermediately depressed by tumor necrosis factor-alpha (TNF-alpha), and markedly depressed by transforming growth factor-beta (TGF-beta). TNF-alpha, however, enhanced the stimulation by a high dose of IFN-gamma, whereas TGF-beta markedly depressed the stimulations given by IFN-gamma and IL-1 alpha. The ratio between the maximal stimulation and depression observed was around 30-fold. The responses were generally slow and developed over periods of several days. There were no effects of IFN-alpha, IL-2, IL-3, IL-4, IL-6, IL-8, granulocyte-macrophage colony-stimulating factor, human growth hormone, Escherichia coli lipopolysaccharide, leukotriene B4, prostaglandin E2, formylmethionylleucylphenylalanine, platelet-activating factor, and indomethacin. The cytokines influencing the EC-SOD expression are also known to influence superoxide production by leukocytes and other cell types, and the EC-SOD response pattern is roughly compatible with the notion that its function is to protect cells against extracellular superoxide radicals. The results show that EC-SOD is a participant in the complex inflammatory response orchestrated by cytokines. The CuZn-SOD activity of the fibroblasts was not influenced by any of the cytokines, whereas the Mn-SOD activity was depressed by TGF-beta. TNF-alpha, IL-1 alpha, and IFN-gamma stimulated the Mn-SOD activity, as previously known, and these responses were reduced by TGF-beta. The different responses of the three SOD isoenzymes illustrate their different physiological roles.
Superoxide dismutase reduces injury in many disease processes, implicating superoxide anion radical (O2-.) as a toxic species in vivo. A critical target of superoxide may be nitric oxide (NO.) produced by endothelium, macrophages, neutrophils, and brain synaptosomes. Superoxide and NO. are known to rapidly react to form the stable peroxynitrite anion (ONOO-). We have shown that peroxynitrite has a pKa of 7.49 +/- 0.06 at 37 degrees C and rapidly decomposes once protonated with a half-life of 1.9 sec at pH 7.4. Peroxynitrite decomposition generates a strong oxidant with reactivity similar to hydroxyl radical, as assessed by the oxidation of deoxyribose or dimethyl sulfoxide. Product yields indicative of hydroxyl radical were 5.1 +/- 0.1% and 24.3 +/- 1.0%, respectively, of added peroxynitrite. Product formation was not affected by the metal chelator diethyltriaminepentaacetic acid, suggesting that iron was not required to catalyze oxidation. In contrast, desferrioxamine was a potent, competitive inhibitor of peroxynitrite-initiated oxidation because of a direct reaction between desferrioxamine and peroxynitrite rather than by iron chelation. We propose that superoxide dismutase may protect vascular tissue stimulated to produce superoxide and NO. under pathological conditions by preventing the formation of peroxynitrite.
Three isozymes of nitric oxide (NO) synthase (EC 1.14.13.39) have been identified and the cDNAs for these enzymes isolated. In humans, isozymes I (in neuronal and epithelial cells), II (in cytokine-induced cells), and III (in endothelial cells) are encoded for by three different genes located on chromosomes 12, 17, and 7, respectively. The deduced amino acid sequences of the human isozymes show less than 59% identity. Across species, amino acid sequences for each isoform are well conserved (> 90% for isoforms I and III, > 80% for isoform II). All isoforms use L-arginine and molecular oxygen as substrates and require the cofactors NADPH, 6(R)-5,6,7,8-tetrahydrobiopterin, flavin adenine dinucleotide, and flavin mononucleotide. They all bind calmodulin and contain heme. Isoform I is constitutively present in central and peripheral neuronal cells and certain epithelial cells. Its activity is regulated by Ca2+ and calmodulin. Its functions include long-term regulation of synaptic transmission in the central nervous system, central regulation of blood pressure, smooth muscle relaxation, and vasodilation via peripheral nitrergic nerves. It has also been implicated in neuronal death in cerebrovascular stroke. Expression of isoform II of NO synthase can be induced with lipopolysaccharide and cytokines in a multitude of different cells. Based on sequencing data there is no evidence for more than one inducible isozyme at this time. NO synthase II is not regulated by Ca2+; it produces large amounts of NO that has cytostatic effects on parasitic target cells by inhibiting iron-containing enzymes and causing DNA fragmentation. Induced NO synthase II is involved in the pathophysiology of autoimmune diseases and septic shock. Isoform III of NO synthase has been found mostly in endothelial cells. It is constitutively expressed, but expression can be enhanced, eg, by shear stress. Its activity is regulated by Ca2+ and calmodulin. NO from endothelial cells keeps blood vessels dilated, prevents the adhesion of platelets and white cells, and probably inhibits vascular smooth muscle proliferation.
Oxidative stress and expression of the vascular cell adhesion molecule-1 (VCAM-1) on vascular endothelial cells are early features in the pathogenesis of atherosclerosis and other inflammatory diseases. Regulation of VCAM-1 gene expression may be coupled to oxidative stress through specific reduction-oxidation (redox) sensitive transcriptional or posttranscriptional regulatory factors. In cultured human umbilical vein endothelial (HUVE) cells, the cytokine interleukin 1 beta (IL-1 beta) activated VCAM-1 gene expression through a mechanism that was repressed approximately 90% by the antioxidants pyrrolidine dithiocarbamate (PDTC) and N-acetylcysteine (NAC). Furthermore, PDTC selectively inhibited the induction of VCAM-1, but not intercellular adhesion molecule-1 (ICAM-1), mRNA and protein accumulation by the cytokine tumor necrosis factor-alpha (TNF alpha) as well as the noncytokines bacterial endotoxin lipopolysaccharide (LPS) and double-stranded RNA, poly(I:C) (PIC). PDTC also markedly attenuated TNF alpha induction of VCAM-1-mediated cellular adhesion. In a distinct pattern, PDTC partially inhibited E-selectin gene expression in response to TNF alpha but not to LPS, IL-1 beta, or PIC. TNF alpha and LPS-mediated transcriptional activation of the human VCAM-1 promoter through NF-kappa B-like DNA enhancer elements and associated NF-kappa B-like DNA binding proteins was inhibited by PDTC. These studies suggest a molecular linkage between an antioxidant sensitive transcriptional regulatory mechanism and VCAM-1 gene expression that expands on the notion of oxidative stress as an important regulatory signal in the pathogenesis of atherosclerosis.
To evaluate the relationship between changes in physical fitness and risk of mortality in men.
Prospective study, with two clinical examinations (mean interval between examinations, 4.9 years) to assess change or lack of change in physical fitness as associated with risk of mortality during follow-up after the subsequent examination (mean follow-up from subsequent examination, 5.1 years).
Preventive medicine clinic.
Participants were 9777 men given two preventive medical examinations, each of which included assessment of physical fitness by maximal exercise tests and evaluation of health status.
All cause (n = 223) and cardiovascular disease (n = 87) mortality.
The highest age-adjusted all-cause death rate was observed in men who were unfit at both examinations (122.0/10,000 man-years); the lowest death rate was in men who were physically fit at both examinations (39.6/10,000 man-years). Men who improved from unfit to fit between the first and subsequent examinations had an age-adjusted death rate of 67.7/10,000 man-years. This is a reduction in mortality risk of 44% (95% confidence interval, 25% to 59%) relative to men who remained unfit at both examinations. Improvement in fitness was associated with lower death rates after adjusting for age, health status, and other risk factors of premature mortality. For each minute increase in maximal treadmill time between examinations, there was a corresponding 7.9% (P = .001) decrease in risk of mortality. Similar results were seen when the group was stratified by health status, and for cardiovascular disease mortality.
Men who maintained or improved adequate physical fitness were less likely to die from all causes and from cardiovascular disease during follow-up than persistently unfit men. Physicians should encourage unfit men to improve their fitness by starting a physical activity program.
Nitric oxide and superoxide, which are produced by several cell types, rapidly combine to form peroxynitrite. This reaction can result in nitric oxide scavenging, and thus mitigation of the biological effects of superoxide. Also, superoxide can trap and hence modulate the effects of nitric oxide; superoxide dismutase, by controlling superoxide levels, therefore can influence the reaction pathways open to nitric oxide. The production of peroxynitrite, however, causes its own sequelae of events: Although neither .NO nor superoxide is a strong oxidant, peroxynitrite is a potent and versatile oxidant that can attack a wide range of biological targets. The peroxynitrite anion is relatively stable, but its acid, peroxynitrous acid (HOONO), rearranges to form nitrate with a half-life of approximately 1 s at pH 7, 37 degrees C. HOONO exists as a Boltzmann distribution of rotamers; at 5-37 degrees C HOONO has an apparent acidity constant, pKa,app, of 6.8. Oxidation reactions of HOONO can involve two-electron processes (such as an SN2 displacement) or a one-electron transfer (ET) reaction in which the substrate is oxidized by one electron and peroxynitrite is reduced. These oxidation reactions could involve one of two mechanisms. The first mechanism is homolysis of HOONO to give HO. and .NO2, which initially are held together in a solvent cage. This caged pair of radicals (the "geminate" pair) can either diffuse apart, giving free radicals that can perform oxidations, or react together either to form nitrate or to reform HOONO (a process called cage return). A large amount of cage return can explain the small entropy of activation (Arrhenius A-factor) observed for the decomposition of HOONO. A cage mechanism also can explain the residual yield of nitrate that appears to be formed even in the presence of high concentrations of all of the scavengers studied to date, since scavengers capture only free HO. and .NO2 and not caged radicals. If the cage mechanism is correct, the rate of disappearance of peroxynitrite be slower in solvents of higher viscosity, and we do not find this to be the case. The second mechanism is that an activated isomer of peroxynitrous acid, HOONO*, can be formed in a steady state. The HOONO* mechanism can explain the inability of hydroxyl radical scavengers to completely block either nitrate formation or the oxidation of substrates such as methionine, since HOONO* would be less reactive, and therefore more selective, than the hydroxyl radical itself.(ABSTRACT TRUNCATED AT 400 WORDS)
Extracellular superoxide dismutase (EC-SOD) is a secretory SOD isoenzyme. 99% of EC-SOD is anchored to heparan sulfate proteoglycans in the tissue interstitium, and 1% is located in the vasculature in equilibrium between the plasma and the endothelium. Analysis of EC-SOD in plasma samples from 504 random blood donors revealed a common (2.2%) phenotypic variant displaying 10-fold increased plasma EC-SOD content. The EC-SOD in the plasma of these individuals, collected both before and after intravenous injection of heparin, displayed a reduced heparin affinity when compared with samples from normal individuals. The specific enzymatic activity was the same as that of normal enzyme. Nucleotide sequence analyses of two of the affected subjects revealed a nucleotide exchange resulting in a substitution of Arg-213 by Gly. The substitution is located in the center of the carboxyl-terminal cluster of positively charged amino acid residues, which defines the heparin-binding domain. Polymerase chain reaction-single-strand conformational polymorphism and allele-specific polymerase chain reaction showed that all 11 affected individuals are heterozygous, carrying the same single-base mutation. Recombinant EC-SOD containing this mutation had a reduced heparin affinity similar to that of EC-SOD C from variant persons. The high plasma activity can be explained by an accelerated release from the tissue interstitium heparan sulfate to the vasculature and should thus be accompanied by significantly reduced tissue EC-SOD activities.
Oxidation of lipoproteins is important for the initiation and propagation of the atherosclerotic lesion and may involve secondary oxidants derived from nitric oxide. Nitric oxide (NO) reacts at near diffusion limited rates with superoxide (O2-.) to form the strong oxidant, peroxynitrite (ONOO-). Nitration on the ortho position of tyrosine is a major product of peroxynitrite attack on proteins. Nitrotyrosine was detected in atherosclerotic lesions of formalin-fixed human coronary arteries with polyclonal and monoclonal antibodies. Binding was pronounced in and around foamy macrophages within the atheroma deposits. Nitration was also observed in early subintimal fatty streaks. Antibody binding was completely blocked by co-incubation with 10mM nitrotyrosine, but not by equivalent concentrations of aminotyrosine or phosphotyrosine. The presence of nitrotyrosine indicates that oxidants derived from nitric oxide such as peroxynitrite are generated in human atherosclerosis and may be involved in its pathogenesis.
Extracellular-superoxide dismutase (EC-SOD) levels in sera divide into two discontinuous groups: a low-level group below 400 ng/ml and a high-level group above 400 ng/ml [Adachi, Nakamura, Yamada, Futenma, Kato and Hirano (1994) Clin. Chim. Acta 229, 123-131]. Molecular genetic studies have shown that the donors in the high-level group have a single base substitution generating the exchange of glycine for arginine-213 (R213G) in the heparin-binding domain of EC-SOD [Sandström, Nilsson, Karlsson and Marklund (1994) J. Biol. Chem. 269, 19163-19166; Yamada, Yamada, Adachi, Goto, Ogasawara, Futenma, Kitano, Hirano and Kato (1995) Jpn. J. Hum. Genet. 40, 177-184]. The serum EC-SOD level in homozygote subjects was significantly higher than that in heterozygotes and in normal subjects. Serum EC-SOD from heterozygotes and homozygotes had equally decreased affinity for heparin, as judged by heparin-HPLC, as compared with that from normal donors. This result suggests that the serum EC-SOD in heterozygotes was mainly composed of the mutant form which has reduced heparin affinity. On the other hand, fibroblast cells derived from heterozygote subjects generated mRNA of both normal and mutant EC-SOD (m-EC-SOD), and expressed the corresponding proteins. EC-SOD is a tetrameric enzyme, and in heterozygote donors would be heterogeneous with regard to the constitution of normal and mutant subunits. The enzyme form consisting of only mutant subunits, the form with the weakest heparin affinity, can be preferentially driven out to the plasma phase, because EC-SOD in the vasculature exists in equilibrium between plasma and the endothelial cell surface. The binding of m-EC-SOD to bovine aortic endothelial cells was about 50-fold less than that of normal EC-SOD. This result suggests that the binding of m-EC-SOD to vascular endothelial cells is much decreased in vivo, which causes a high level of serum EC-SOD.
We tested the hypothesis that angiotensin II-induced hypertension is associated with an increase in vascular .O2- production, and characterized the oxidase involved in this process. Infusion of angiotensin II (0.7 mg/kg per d) increased systolic blood pressure and doubled vascular .O2- production (assessed by lucigenin chemiluminescence), predominantly from the vascular media. NE infusion (2.75 mg/kg per d) produced a similar degree of hypertension, but did not increase vascular .O2- production. Studies using various enzyme inhibitors and vascular homogenates suggested that the predominant source of .O2- activated by angiotensin II infusion is an NADH/NADPH-dependent, membrane-bound oxidase. Angiotensin II-, but not NE-, induced hypertension was associated with impaired relaxations to acetylcholine, the calcium ionophore A23187, and nitroglycerin. These relaxations were variably corrected by treatment of vessels with liposome-encapsulated superoxide dismutase. When Losartan was administered concomitantly with angiotensin II, vascular .O2- production and relaxations were normalized, demonstrating a role for the angiotensin type-1 receptor in these processes. We conclude that forms of hypertension associated with elevated circulating levels of angiotensin II may have unique vascular effects not shared by other forms of hypertension because they increase vascular smooth muscle .O2- production via NADH/NADPH oxidase activation.
Studies examining the biochemical characteristics and pharmacological properties of extracellular superoxide dismutase (EC SOD) have been severely limited because of difficulties in purifying the enzyme. Recently EC SOD was found to exist in high concentrations in the arteries of most mammals examined and it is the predominant form of SOD activity in many arteries. We now describe a three-step, high-yield protocol for the purification of EC SOD from human aorta. In the first step, the high affinity of EC SOD for heparin is utilized to obtain a fraction in which EC SOD constitutes roughly 13% of the total protein compared with only 0.3% of that of the starting material. In addition, over 80% of the original EC SOD activity present in the aortic homogenate was retained after the first step of purification. EC SOD was further purified using a combination of cation- and anion-exchange chromatography. The overall yield of EC SOD from this purification procedure was 46%, with over 4 mg of EC SOD obtained from 230 g of aorta. Purified EC SOD was found to exist predominantly as a homotetramer composed of two disulphide-linked dimers. However, EC SOD was also found to form larger multimers when analysed by native PAGE. It was shown by urea denaturation that the formation of multimers increased the thermodynamic stability of the protein. Limited proteolysis of EC SOD suggested that there is one interchain disulphide bond covalently linking two subunits. This disulphide bond involves cysteine-219 and appears to link the heparin-binding domains of the two subunits.
This chapter focuses on the physiological and pathological chemistry of nitric oxide. Nitric oxide is a simple molecule, consisting of single oxygen bonded to one nitrogen atom. Mammalian cells were discovered to produce nitric oxide (NO) as a short-lived intercellular messenger. The physiological implications continue to rapidly expand and have so far implicated nitric oxide in the regulation of blood pressure, platelet adhesion, neutrophil aggregation, as well as synaptic plasticity in brain. Nitric oxide and its secondary oxidants are also major cytotoxic agents produced by activated macrophages and neutrophils. This chapter begins with a discussion on why does nitric oxide have an unpaired electron. The chapter also discusses why half-life of nitric oxide is so short in vivo. It further explains concepts related to chemistry of nitric oxide and related nitrogen oxides. The chapter also describes handling and detection of nitric oxide. An overview of pathological implications of tyrosine nitration is also presented in this chapter. The chapter elaborates, in detail, the reactions with trace metal contaminants. The chapter concludes with a discussion on the chemistry of nitric oxide reacting with superoxide.
The production of superoxide and nitric oxide individually has been associated with the development of several diseases but only recently has it been realised that interactions between them may also be important in disease pathology. The central hypothesis which is emerging is that the balance between nitric oxide and superoxide generation is a critical determinant in the aetiology of many human diseases including atherosclerosis, neurodegenerative disease, ischaemia-reperfusion and cancer. These ideas are discussed in this short overview and placed in the context of the current and future status of therapies which could modulate the balance between nitric oxide and superoxide.
Bovine erythrocyte superoxide dismutase was slowly and irreversibly inactivated by hydrogen peroxide. The rate of this inactivation was directly dependent upon the concentrations of both H2O2 and of enzyme, and its second-order rate constant at pH 10.0 and 25 degrees was 6.7 M-1 sec-1. Inactivation was preceded by a bleaching due to rapid reduction of Cu2+ on the enzyme, and following this there was a gradual reappearance of a new absorption in the visible region, which was coincident with the loss of catalytic activity. Inactivation of the enzyme was pH-dependent and indicated an essential ionization whose pKa was approximately 10.2. Replacement of H2O by D2O raised this pKa but did not diminish the catalytic activity of superoxide dismutase, measured at pH 10.0. Several compounds, including xanthine, urate, formate, and azide, protected the enzyme against inactivation by H2O2. Alcohols and benzoate, which scavenge hydroxyl radical, did not protect. Compounds with special affinity for singlet oxygen were similarly ineffective. The data were interpreted in terms of the reduction of the enzyme-bound Cu2+ to Cu+, by H2O2, followed by a Fenton's type reaction of the Cu+ with additional H2O2. This would generate Cu2+-OH- or its ionized equivalent, Cu2+-O--, which could then oxidatively attack an adjacent histidine and thus inactivate the enzyme. Compounds which protected the enzyme could have done so by reacting with the bound oxidant, in competition with the adjacent histidine.
Extracellular superoxide dismutase type C (EC-SOD C) is a secretory SOD isoenzyme that, in vivo, is bound to heparan sulfate proteoglycans in the glycocalyx of various cell types (e.g., endothelial cells) and in the connective tissue matrix. The aim of this study was to investigate the efficacy of vascular bound EC-SOD C in protecting arterial relaxation mediated by endothelium-derived relaxing factor (EDRF) against the inhibitory effects of superoxide radicals. For comparison, the effect of CuZn SOD was also studied. This SOD isoenzyme lacks affinity toward heparan sulfate and does not bind to cell surfaces. Rings from rabbit aorta were mounted in an organ bath and acetylcholine-induced endothelium-dependent relaxation was then studied in preparations precontracted with phenylephrine. Pyrogallol (10(-4) M), used to generate superoxide radicals, reduced the maximal relaxant effect of acetylcholine from about 65% to 25%. When present in the buffer throughout the experiment, CuZn SOD and EC-SOD C caused a concentration-dependent prevention of the pyrogallol effect on EDRF-mediated relaxation, with a half-maximal effect at about 100 units/ml (KO2 assay). In a second set of experiments, the arterial rings were preincubated with 8,000 units/ml CuZn SOD (50 micrograms/ml) or EC-SOD C (69 micrograms/ml) during 30 minutes, followed by washing, before the effect of pyrogallol on EDRF-mediated relaxation was studied in SOD-free buffer.(ABSTRACT TRUNCATED AT 250 WORDS)
The efficacy of human extracellular-superoxide dismutase type C (EC-SOD C) to limit infarct size after ischemia and reperfusion was explored and compared to that of EC-SOD C combined with catalase (CAT) and to that of CAT alone. EC-SOD C binds to heparan sulphate proteoglycan on the cell surfaces. Thirty-two pigs were subjected to 45 min of myocardial ischemia followed by 4 h of reperfusion. Control pigs (group A; n = 8) received 300 mL of saline into the great cardiac vein during a 30-min period started 5 min prior to reperfusion; pigs in group B (EC-SOD C; n = 8) got 16.6 mg of EC-SOD C; pigs in group C (EC-SOD C + CAT; n = 8) got 16.6 mg of EC-SOD C together with 150 mg of CAT. Pigs in group D (CAT; n = 8) received 150 mg of CAT. In groups B, C, and D, the drug was dissolved in saline and infused into the great cardiac. Infarct size expressed as percent of area at risk was smaller in groups B (14.5 +/- 16.7%) and C (40.8 +/- 13.3%) than in groups A (78.8 +/- 8.6%) and D (67.2 +/- 18.6%; p less than .05). Creatine kinase (CK) activity in ischemic myocardium was higher in groups B (1740 +/- 548 U/g) and C (1729 +/- 358 U/g) than in groups A (1184 +/- 237 U/g) and D (1251 +/- 434 U/g; p less than .05). There was an inverse relation (r = -.83) between infarct size and CK content. The EC-SOD C infusions resulted in only minimal increases in plasma SOD activities. In conclusion, the presence of SOD on the cell surfaces is of importance in the prevention of reperfusion injury rather than circulating SOD.
The efficacy of recombinant human extracellular-superoxide dismutase type C (EC-SOD C) on myocardial reperfusion injury was explored in hypothermically arrested rat hearts, as was its site of action. Forty isolated working rat hearts were subjected to 30 min of global ischemia followed by 30 min of reperfusion. The hearts were arrested by the administration of 10 mL of cold perfusate at the onset of ischemia. At the same time, they were randomly assigned to one of five groups; A: cold perfusate only; B: cold perfusate + EC-SOD C 10.4 mg/L (30,000 U/L); C: cold perfusate+bovine CuZn-SOD 7.5 mg/L (30,000 U/L); D: cold perfusate + EC-SOD C 10.4 mg/L + heparin 50,000U/L; E: cold perfusate + heparin 50,000 U/L. Heparin was given to prevent binding of EC-SOD C to endothelial cell surfaces. Left ventricular function was studied before ischemia and at the end of reperfusion. Percent recovery of maximal left ventricular dP/dt after reperfusion was more pronounced in group B (109 +/- 24%; p less than .05) than in groups A (42 +/- 40%), C (47 +/- 36%), D (44 +/- 33%) and E (58 +/- 25%). Likewise, percent recovery of the double product (heart rate x systolic left ventricular pressure) was better in group B (104 +/- 18%; p less than .05) than in the other groups (A: 47 +/- 37%, C: 49 +/- 36%, D: 50 +/- 35%, E: 69 +/- 31%). Compared to the preischemic level, creatine kinase increased significantly in the coronary effluent after reperfusion in groups A, C, D, and E, but not in group B. The results suggest that EC-SOD C, which attaches to the endothelial cell surfaces, might be particularly effective as protection against myocardial reperfusion injury when given together with cardioplegic solution.
The aim was to determine if endothelium associated extracellular superoxide dismutase type C (EC-SOD C) exerts any protective effect against cardiac damage induced by ischaemia and reperfusion.
Langendorff perfused rat hearts were subjected to 15 min global ischaemia followed by reperfusion. Prior to the ischaemia the hearts were perfused for 15 min with a buffer containing recombinant human EC-SOD C (rh-EC-SOD C, 20 mg.litre-1), or the corresponding vehicle, followed by extensive perfusion with SOD free medium.
In hearts receiving the vehicle, reperfusion was associated with a marked release of creatine kinase into the effluent [28 (SEM 1.5) IU.15 min-1, n = 5] and coronary flow measured 15 min after initiation of reperfusion was reduced by 68% compared to preischaemic flow. In hearts pretreated with EC-SOD C but washed with enzyme free buffer before being subjected to ischaemia, the creatine kinase release was significantly smaller, at 14(2.1) IU.min-1, n = 5 (p less than 0.001), and the reduction in coronary flow less extensive (54%, p less than 0.05, v vehicle). To demonstrate the binding of EC-SOD C to the endothelium, heparin, which releases EC-SOD C from the endothelial surfaces, was added to the perfusate 30 min after initiation of reperfusion. The same amount of EC-SOD C was released to the effluent from previously ischaemic hearts [(12.4(2) micrograms)] as from hearts not subjected to ischaemia [(13.8(1.4) micrograms)].
Recombinant human EC-SOD type C bound to the endothelial surface reduces the cardiac damage associated with ischaemia and reperfusion. The protective effect was evident both in terms of a reduction of biochemical markers of injury and a better preservation of postischaemic coronary flow. Furthermore, ischaemia and subsequent reperfusion did not cause any alteration in the binding capacity of EC-SOD C to the cardiac vasculature.
Endothelial cells, macrophages, neutrophils, and neuronal cells generate superoxide (O2-) and nitric oxide (.NO) which can combine to form peroxynitrite anion (ONOO-). Peroxynitrite, known to oxidize sulfhydryls and to yield products indicative of hydroxyl radical (.OH) reaction with deoxyribose and dimethyl sulfoxide, is shown herein to induce membrane lipid peroxidation. Peroxynitrite addition to soybean phosphatidylcholine liposomes resulted in malondialdehyde and conjugated diene formation, as well as oxygen consumption. Lipid peroxidation was greater at acidic and neutral pH, with no significant lipid peroxidation occurring above pH 9.5. Addition of ferrous (Fe+2) or ferric (Fe+3) iron did not enhance lipid peroxide formation over that attributable to peroxynitrite alone. Diethylenetetraminepentacetic acid (DTPA) or iron removal from solutions by ion-exchange chromatography decreased conjugated diene formation by 25-50%. Iron did not play an essential role in initiating lipid peroxidation, since DTPA and iron depletion of reaction systems were only partially inhibitory. In contrast, desferrioxamine had an even greater concentration-dependent inhibitory effect, completely abolishing lipid peroxidation at 200 microM. The strong inhibitory effect of desferrioxamine on lipid peroxidation was due to direct reaction with peroxynitrous acid in addition to iron chelation. We conclude that the conjugate acid of peroxynitrite, peroxynitrous acid (ONOOH), and/or its decomposition products, i.e., .OH and nitrogen dioxide (.NO2), initiate lipid peroxidation without the requirement of iron. These observations demonstrate a potential mechanism contributing to O2-(-)and .NO-mediated cytotoxicity.
The cardioprotective effect of recombinant human extracellular-superoxide dismutase type C (rh-EC-SOD C) was studied in isolated perfused rat heart subjected to left coronary artery ligation for 30 or 60 min followed by 30-min reperfusion. A comparison was made with the effects of bovine CuZn-SOD. Reperfusion after 30-min coronary artery ligation was associated with a release of creatine kinase (CK) into the coronary effluent (71 +/- 5.2 IU/30 min), which was markedly reduced (39 +/- 5.5 IU/30 min) in hearts perfused with rh-EC-SOD C (28 mg/L). CuZn-SOD (4 or 20 mg/l) or a lower concentration of rh-EC-SOD C (5.6 mg/l) did not significantly attenuate CK outflow during reperfusion, however. In both vehicle- and SOD-treated hearts, the left ventricular developed pressure (LVDP) and the coronary flow recovered to 80-90% of baseline at the end of the reperfusion period. Increasing the ischemic period from 30 to 60 min caused a much more pronounced cardiac injury measured after 30-min reperfusion. In the hearts that received vehicle, recovery of LVDP (in percentage of baseline values) at the end of reperfusion was 58 +/- 2%, which was increased to 84 +/- 3 and 83 +/- 5% after treatment with rh-EC-SOD C (28 mg/L) and CuZn-SOD (20 mg/L), respectively. The corresponding values for recovery in coronary flow were 54 +/- 3% (vehicle), 69 +/- 4% (rh-EC-SOD C), and 74 +/- 3% (CuZn-SOD).(ABSTRACT TRUNCATED AT 250 WORDS)
The availability of a spectrophotometric assay for superoxide dismutase (SOD) activity and of an activity stain applicable to polyacrylamide gels facilitated the isolation of SODS from a variety of sources. A manganese-containing SOD (Mn-SOD) was rather quickly isolated from Escherichia coli (13) and from chicken liver mitochondria and an iron-containing SOD (Fe-SOD) was isolated from E. coli. These SODS are widely distributed, abundant and stable, and thus are well-suited for the studies of structure, function, and evolution. In some cases, the distribution of SODS provides a clear indication of evolutionary history, while in other cases remain enigmatic. Mitochondria contain a Mn-SOD, while the cytosols of eukaryotic cells contain a Cu,Zn-SOD. The mitochondria1 Mn-SOD is strikingly homologous to the Mn-SODs/Fe-SODs found in prokaryotes, but bears no resemblance to the cytosolic Cu,Zn-SOD, which supports the idea of an endosymbiotic origin for this organelle.
We examined the effect of preischemic equilibration of the rabbit heart with superoxide dismutase (SOD) on the extent of recovery of contractile function following an episode of ischemia. First, hearts were perfused with Krebs-Henseleit buffer. The pulmonary artery was cannulated and its flow diverted as the vascular effluent, and all other orifices were tied off. The fluid seeping from the epicardial surface represented the interstitial outflow. SOD was added to the perfusate and the interstitial and vascular effluents were assayed for SOD at regular intervals. Second, hearts were perfused in the Langendorff mode. SOD was included in the perfusate at all times at 20,000 U/l. After either 15 or 50 min of equilibration the hearts were subjected to 1 h of ischemia followed by 1 h of reperfusion. The developed tension was measured via a balloon in the left ventricle. Control hearts showed a recovery of developed tension of 63 +/- 12%. Human recombinant (h) Cu,Zn-SOD, which equilibrated with the interstitial fluid by 20 +/- 10% and 92 +/- 7% after 15 and 60 min of perfusion respectively, caused a recovery of 68 +/- 29% (non-significant) and 92 +/- 18% (P less than 0.01) with 15 and 50 min of equilibration respectively. The positively charged hrMn-SOD and sheep Cu,Zn-SOD, however, equilibrated much faster reaching 84 +/- 13% and 95 +/- 11% at 15 min respectively, which correlated with a recovery of 99 +/- 11% and 96 +/- 10% (P less than 0.01) respectively. HrCu,Zn-SOD conjugated to polyethylene glycol equilibrated much slower reaching 38 +/- 10% after 1 h, which correlated with lack of protection even after 50 min of equilibration. Therefore, the protection afforded by SOD to the isolated rabbit heart correlates with the concentration of SOD in the interstitial fluid. The rate of equilibration depends on the charge as well as the size of the enzyme.
Extracellular superoxide dismutase (EC-SOD) is the major SOD isoenzyme in extracellular fluids, but occurs also in tissues. The sites and characteristics of the synthesis of the enzyme are unknown. The occurrence of EC-SOD in cultures of a large panel of human cell lines was assayed by means of an e.l.i.s.a. Unlike the situation for the intracellular isoenzymes CuZn-SOD and Mn-SOD, expression of EC-SOD occurs in only a few cell types. None of the ten investigated suspension-growing cell lines produced EC-SOD. Among normal diploid anchorage-dependent cell lines, expression was found in all 25 investigated fibroblast cell lines, in the two glia-cell lines, but not in six endothelial-cell lines, two epithelial-cell lines or in two amnion-derived lines. Among neoplastic anchorage-dependent cell lines expression was found in 13 out of 29. EC-SOD was secreted into the culture medium by cell lines expressing the enzyme. The rate of EC-SOD synthesis varied by nearly 100-fold among the fibroblast lines and remained essentially constant in the individual lines during long-term culture. In the nine investigated cases, the secreted EC-SOD was of the high-heparin-affinity C type. It is suggested that tissue EC-SOD is secreted by a few well-dispersed cell types, such as fibroblasts and glia cells, to diffuse subsequently around and reversibly bind to heparan sulphate proteoglycan ligands in the glycocalyx of the surface of most tissue cell types and in the interstitial matrix.
Glycosaminoglycans (GAGs) were studied in normal and atherosclerotic coronary arteries of 15- to 60-year-old Finnish men who had died accidentally. The GAGs were fractionated and quantified with electrophoretic techniques. The contents of sulfated GAGs (micrograms/cm2 vessel surface area) increased continuously until 20 to 30% of the vessel surface area was covered with fibrous plaques, after which they started to decrease. The largest increases were seen in chondroitin sulfates A and C and dermatan sulfate, the former of which rose earlier with lesion development. In normal coronary arteries the contents of dermatan sulfate and chondroitin sulfates A and C increased significantly with age, but the rises were much smaller than those found in affected vessels. The age-related changes in the percentage composition of GAGs in normal coronaries were qualitatively similar to those found in affected coronaries during lesion development. The alterations in arterial GAGs, therefore, seem to be related to two processes, both of which involve increased formation of connective tissue components by arterial smooth muscle cells: the normal growth and maturation of the vessels with a slow development of diffuse intimal thickening, and atherogenesis, which greatly increases the contents of sulfated GAGs in affected arteries.
Extracellular superoxide dismutase (SOD) has previously been shown to be the major SOD isoenzyme in extracellular fluids. Upon chromatography on heparin-Sepharose it was separated into three fractions: A, without affinity; B, with intermediate affinity; and C, with relatively strong heparin affinity. Intravenous injection of heparin leads to a prompt increase in plasma extracellular-superoxide-dismutase (EC-SOD) activity. Heparin induces no release of EC-SOD from blood cells, nor does it activate EC-SOD in plasma, indicating that the source of the released enzyme is the endothelial-cell surfaces. No distinct saturation could be demonstrated in a dose-response curve up to 200 i.u. of heparin per kg body weight, showing that the releasing potency of heparin is lower for EC-SOD than for previously investigated heparin-released factors. Chromatography of human plasma on heparin-Sepharose shows nearly equal amounts of EC-SOD fractions A, B and C. Heparin induces specifically the release of fraction C. The findings point to the existence of an equilibrium of EC-SOD fraction C between the plasma phase and endothelial-cell surfaces. The major part of EC-SOD in the vasculature seems to be located on endothelial-cell surfaces.
The chemistry of molecular oxygen, or dioxygen as it is increasingly coming to be called, is dominated by the relative reluctance with which the element reacts with most, but not all, compounds. This quality is rarely thermodynamic in origin; rather the slow rate of reaction is associated with either the strong oxygen–oxygen bond or the character of the ground state of dioxygen or both. If a reaction is to take place with dioxygen in its ground state, there must be a change of spin at some stage during the reaction. This is forbidden, within the limitations of the descriptions used; at the very least, the reactions are improbable. For dioxygen to react rapidly, this spin restriction should be removed or the oxygen–oxygen bond should be partially weakened or both of these should occur simultaneously. It is not surprising that much of the chemistry of dioxygen is concerned with reactions with paramagnetic species, with electron-donating species, with light, or with various combinations of these three factors. This chapter discusses the chemistry of the reduction products of dioxygen, but one should be aware of the marked influence of all of these factors on most reactions of dioxygen. They are often, if not always, responsible for the promotion or catalysis of oxidation reactions.
A superoxide dismutase (superoxide:superoxide oxidoreductase, EC 1.15.1.1), distinct from previously known superoxide dismutases, has been isolated from human lung tissue. It is probably of the same nature as a previously demonstrated high molecular weight superoxide dismutating factor in human extracellular fluids. The enzyme has a molecular weight around 135,000 and is composed of four equal noncovalently bound subunits. Each molecule appears to have four copper atoms. No iron or manganese was found in the enzyme. Cyanide inhibits the enzyme efficiently. The enzyme brings about a first-order dismutation of the superoxide radical, the rate constant for the catalyzed reaction being about 1 X 10(9) M-1 s-1 per copper atom. The enzyme has hydrophobic properties. Affinity for various lectins indicates the presence of carbohydrate. Upon chromatography on heparin-Sepharose it is divided into three fractions, one with no, one with weak, and one with strong affinity for heparin.
Recently, we have shown that chronic exercise increases endothelium-derived relaxing factor (EDRF)/nitric oxide (NO)-mediated epicardial coronary artery dilation in response to brief occlusion and acetylcholine. This finding suggests that exercise can provide a stimulus for the enhanced production of EDRF/NO, thus possibly contributing to the beneficial effects of exercise on the cardiovascular system. Therefore, the purpose of the present study was to examine whether chronic exercise could influence the production of NO (measured as the stable degradation product, nitrite) and endothelial cell NO synthase (ECNOS) gene expression in vessels from dogs after chronic exercise. To this end, dogs were exercised by running on a treadmill (9.5 km/h for 1 hour, twice daily) for 10 days, and nitrite production in large coronary vessels and microvessels and ECNOS gene expression in aortic endothelial extracts were assessed. Acetylcholine (10(-7) to 10(-5) mol/L) dose-dependently increased the release of nitrite (inhibited by nitro-L-arginine) from coronary arteries and microvessels in control and exercised dogs. Moreover, acetylcholine-stimulated nitrite production was markedly enhanced in large coronary arteries and microvessels prepared from hearts of dogs after chronic exercise compared with hearts from control dogs. One potential mechanism that may contribute to the enhanced production of nitrite in vessels from exercised dogs may be the induction of the calcium-dependent ECNOS gene. Steady-state mRNA levels for ECNOS were significantly higher than mRNA levels for von Willebrand's factor (vWF, a specific endothelial cell marker) and glyceraldehyde-3-phosphate dehydrogenase (GAPDH, a constitutively expressed gene) in exercised dogs.(ABSTRACT TRUNCATED AT 250 WORDS)
The levels of the secreted, interstitially located extracellular superoxide dismutase (EC-SOD), the cytosolic copper-and-zinc-containing SOD (CuZn-SOD), and the mitochondrial manganese-containing SOD (Mn-SOD) were measured in the walls of human coronary arteries, proximal thoracic aortas, and saphenous veins. The blood vessel walls, particularly the arteries, were found to contain exceptionally large amounts of EC-SOD, whereas the levels of CuZn-SOD and Mn-SOD were relatively low compared with other tissues. Analysis of EC-SOD by immunohistochemistry indicates an even distribution in the vessel wall, including large amounts of the arterial intima. Arterial smooth muscle cells were found to secrete large amounts of EC-SOD and likely are the principal source of the enzyme in the vascular wall. The EC-SOD concentration in the human arterial wall extracellular space is high enough to efficiently suppress the putative pathological effects of the superoxide radical, such as oxidation of LDL and reaction with nitric oxide to form the deleterious peroxynitrite. The levels of EC-SOD in the aortic wall are found to vary widely among species and were on average 6440 U/g in humans, 4340 U/g in the cow, 2660 U/g in the pig, 160 U/g in the dog, 770 U/g in the mouse. There were only moderate differences in the amounts of CuZn-SOD and Mn-SOD. This wide variation in EC-SOD content suggests that the susceptibility to pathologies induced by superoxide radicals in the vascular wall interstitium should vary widely among species.
Extracellular superoxide dismutase (EC-SOD; superoxide:superoxide oxidoreductase, EC 1.15.1.1) is a secreted Cu- and Zn-containing tetrameric glycoprotein, the bulk of which is bound to heparan sulfate proteoglycans in the interstitium of tissues. To test the function of EC-SOD in vivo, mice carrying a targeted disruption of the EC-SOD gene were generated. The EC-SOD null mutant mice develop normally and remain healthy until at least 14 months of age. No compensatory induction of other SOD isoenzymes or other antioxidant enzymes was observed. When stressed by exposure to > 99% oxygen, the EC-SOD null mutant mice display a considerable reduction in survival time compared to wild-type mice and an earlier onset of severe lung edema. These findings suggest that while under normal physiological conditions other antioxidant systems may substitute for the loss of EC-SOD; when the animal is stressed these systems are unable to provide adequate protection.
A model for NF kappa B activation involving reactive oxygen intermediates has recently been proposed. We have explored this model in three cell lines, Jurkat T cells, EL4.NOB-1 T cells and KB epidermal cells using hydrogen peroxide and two physiological activators of NF kappa B, interleukin-1 (IL1) and tumor necrosis factor (TNF) as stimuli. In agreement with earlier studies hydrogen peroxide activated NF kappa B in Jurkat, although only at much higher concentrations (10 mM) than those previously reported. However, hydrogen peroxide failed to activate in the two other cell lines under a range of conditions. Similarly, N-acetylcysteine only proved inhibitory in hydrogen peroxide and TNF treated Jurkat and failed to inhibit IL1 and TNF-activated NF kappa B in EL4.NOB-1 and KB cells respectively. N-Acetylcysteine inhibited IL1-induced interleukin-2 in EL4, however, demonstrating that N-acetylcysteine was biologically active. These results suggest that the reactive oxygen model of NF kappa B activation may be cell-type restricted. In contrast to the results with N-acetylcysteine, the antioxidant and metal chelator, pyrolidine dithiocarbamate (PDTC) inhibited NF kappa B activation, although these effects may be unrelated to any antioxidant properties. PDTC also inhibited IL1-induced interleukin-2. Finally, studies with the pro-oxidant diamide showed that this could not activate NF kappa B in any of the cells and in contrast proved inhibitory. The results from this study therefore suggest that the reactive oxygen model of NF kappa B activation may be restricted to certain cell types and that the presence of such a system is not required for the activation of NF kappa B by IL1 and TNF.