[Show abstract][Hide abstract] ABSTRACT: Current guidelines for the treatment of type 2 diabetes focus on pharmacological treatment of glucose and cardio-vascular risk factors. The aim of this prospective randomized controlled intervention study was to examine the effects of a psychosocial intervention on clinical endpoints and risk factors in patients with type 2 diabetes and early diabetic kidney disease.110 patients were randomized to receive an 8-week mindfulness-based stress reduction (MBSR) training (n=53) compared to standard care (n=57). The study was carried out open-labelled and randomization was performed computer-generated in a 1:1 ratio. Primary outcome of the study was the change in urinary albumin excretion (albumin-creatinine-ratio, ACR); secondary outcomes were metabolic parameters, intima media thickness (IMT), psychosocial parameters and cardiovascular events.89 patients (42 in control group and 47 in intervention group) were analysed after 3 years of follow-up. After 1 year, the intervention group showed a reduction of ACR from 44 [16/80] to 39 [20/71] mg/g, while controls increased from 47 [16/120] to 59 [19/128] mg/g (p=0.05). Parallel to the reduction of stress levels after 1 year, the intervention-group additionally showed reduced catecholamine levels (p<0.05), improved 24 h-mean arterial (p<0.05) and maximum systolic blood pressure (p<0.01), as well as a reduction in IMT (p<0.01). However, these effects were lost after 2 and 3 years of follow-up.This is the first study to show that a psychosocial intervention improves cardiovascular risk factors in high risk type 2 diabetes patients. Trial-Registration: NCT00263419 http://clinicaltrials.gov/ct2/show/NCT00263419 Trial registration: clinicaltrials.gov-Identifier: NCT00263419.
[Show abstract][Hide abstract] ABSTRACT: The effect of metformin on methylglyoxal (MG) metabolism was studied in a prospective non-randomized 24 weeks trial in patients with type 2 diabetes.Metformin treatment, in addition to life style intervention, significantly reduced morning glucose and HbA1c whilst body weight and BMI were only marginally reduced during the 24 week trial. Treatment significantly reduced both plasma MG and carboxymethyl-lysine (CML), a marker of oxidative stress. The reduction in MG was paralleled by a significant increase in the activity of Glyoxalase 1 (Glo1), the major route of MG detoxification, in peripheral blood mononuclear cells and red blood cells. Multivariate analysis showed that the changes in MG were dependent upon the metformin treatment.This study supports previous findings that metformin can reduce plasma MG in type 2 diabetic patients. However, given the observed increase in Glo1 activity, this reduction is due not only to the scavenging properties of metformin, but the restoration of Glo1 activity.
[Show abstract][Hide abstract] ABSTRACT: The clinical symptoms of diabetic neuropathy (DN) manifest in a time dependent manner as a positive symptoms (i. e. pain, hypersensitivity, tingling, cramps, cold feet etc.) during its early stages and by a loss of function (i. e. loss of sensory perception, delayed wound healing etc.) predominating in the later stages. Elevated blood glucose alone cannot explain the development and progression of DN and the lowering of blood glucose is insufficient in preventing and/or reversing neuropathy in patients with type 2 diabetes. Recently it has been shown that the endogenous reactive metabolite methylglyoxal (MG) can contribute to the gain of function via post-translational modification in DN of neuronal ion channels involved in chemosensing and action potential generation in nociceptive nerve endings. Dicarbonyls, such as MG, that are elevated in diabetic patients, modify DNA as well as extra- and intracellular proteins, leading to the formation of advanced glycation endproducts (AGEs). Increased formation of AGEs leads to increased cellular stress, dysfunction and ultimately cell death. The interaction of AGE-modified proteins through cell surface receptors, such as RAGE, can lead to increased cellular activation and sustained inflammatory responses, which are the molecular hallmarks of the later, degenerative, stages of DN. The direct and indirect effects of dicarbonyls on nerves or neuronal microvascular network provides a unifying mechanism for the development and progression of DN. Targeting the accumulation of MG and/or prevention of RAGE interactions may therefore provide new, more effective, therapeutic approaches for the treatment of DN.
[Show abstract][Hide abstract] ABSTRACT: The receptor for advanced glycation endproducts, RAGE, is a multiligand receptor and NF-κB activator leading to perpetuation of inflammation. We investigated whether and how RAGE is involved in mediation of anti-inflammatory properties of protein C.
We analyzed the effect of protein C on leukocyte adhesion and transmigration in WT- and RAGE-deficient mice using intravital microscopy of cremaster muscle venules during trauma- and TNFα-induced inflammation. Both, protein C (PC, Ceprotin, 100 U/kg) and activated protein C (aPC, 24 µg/kg/h) treatment significantly inhibited leukocyte adhesion in WT mice in these inflammation models. The impaired leukocyte adhesion after trauma-induced inflammation in RAGE knockout mice could not be further reduced by PC and aPC. After TNFα-stimulation, however, aPC but not PC treatment effectively blocked leukocyte adhesion in these mice. Consequently, we asked whether RAGE is involved in PC activation. Since RAGE-deficient mice and endothelial cells showed insufficient PC activation, and since thrombomodulin (TM) and endothelial protein C receptor (EPCR) are reduced on the mRNA and protein level in RAGE deficient endothelial cells, an involvement of RAGE in TM-EPCR-dependent PC activation is likely. Moreover, TNFα-induced activation of MAPK and upregulation of ICAM-1 and VCAM-1 are reduced both in response to aPC treatment and in the absence of RAGE. Thus, there seems to be interplay of the RAGE and the PC pathway in inflammation.
RAGE controls anti-inflammatory properties and activation of PC, which might involve EPCR and TM.
PLoS ONE 02/2014; 9(2):e89422. · 3.53 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: The established marker for tubular damage, urinary n-acetyl-beta-d-glucosaminidase is significantly increased in type 1 and 2 diabetes patients and is related to albuminuria and other diabetic complications. In this cross sectional study of type 2 diabetes patients with a history of albuminuria, we studied the relationship between excretion of n-acetyl-beta-d-glucosaminidase in urine and diabetic neuropathy.160 type 2 diabetes patients were screened for diabetic peripheral neuropathy and cardiovascular autonomic neuropathy. N-acetyl-beta-d-glucosaminidase excretion was detected in 24 h urine samples.Urinary excretion of n-acetyl-beta-d-glucosaminidase correlated significantly with -glucose control (fasting glucose r=0.18; p=0.04; HbA1c r=0.20; p=0.02) and urine albumin excretion (r=0.22; p=0.01). Binary regression analyses showed that increased urinary n-acetyl-beta-d-glucosaminidase concentration is an independent predictor for presence of clinical symptoms of peripheral neuropathy (OR 1.8 [95%CI 1.2-2.74] and vibration deficiency [OR 1.7; 95% CI 1.2-2.66]. There was also a significant negative association between urinary n-acetyl-beta-d-glucosaminidase and E/I-Ratio (r=-0.21, p<0.02) as well as the 30:15-Ratio (r=-0.24; p<0.01) of heart rate variability. Furthermore, increased n-acetyl-beta-d-glucosaminidase excretion independently predicted cardiovascular autonomic diabetic neuropathy with an OR for decreased E/I-Ratio of 1.7 [95%CI 1.1-2.75]; (p<0.02) and 30:15-Ratio:OR 2.4 [95% CI 1.26-4.45]; (p<0.01).Urinary n-acetyl-beta-d-glucosami-nidase excretion is an independent marker for diabetic peripheral and cardiovascular autonomic neuropathy in type 2 diabetic patients.
[Show abstract][Hide abstract] ABSTRACT: Glyoxalase 1 catalyses the detoxification of methylglyoxal, a major precursor of advanced glycation end products associated with aging, neurodegenerative diseases, and microvascular complications of diabetes. Here, we examine a possible association of a single nucleotide polymorphism of glyoxalase 1 gene (Glo1 A332C, rs4746 or rs2736654) with the prevalence of microvascular diabetic complications in patients with type 1 and type 2 diabetes.Genotyping was performed in 209 patients with type 1 and 524 patients with type 2 diabetes using polymerase chain reaction and subsequent cleavage by restriction endonuclease Bsa I.Frequencies of the glyoxalase 1 genotypes were different with respect to diabetes type with a significantly higher prevalence of A332A-genotype in type 1 diabetes (35.9% vs. 27.3%; p=0.03). In type 1 diabetes, there was no correlation of any genotype with diabetic retinopathy, nephropathy or neuropathy. In contrast, type 2 diabetic patients homozygous for the C332C allele showed a significantly increased prevalence of diabetic neuropathy (p=0.03; OR=1.49 [95%-CI: 1.04; 2.11]), while no association with diabetic nephropathy or retinopathy was found. However, the significance of this association was lost after correction for multiple testing.Our data suggest a possible association of C332C-genotype of the glyoxalase 1 gene with diabetic neuropathy in type 2 diabetes, supporting the hypothesis that methylglyoxal might be an important mediator of diabetic neuropathy in type 2 diabetes.
[Show abstract][Hide abstract] ABSTRACT: BACKGROUND AND PURPOSE: Rivaroxaban has recently been approved for stroke prevention in atrial fibrillation. However, lack of an effective antidote represents a major concern in the event of intracerebral hemorrhage (ICH). The aims of the present study were to establish a murine model of ICH associated with rivaroxaban, and to examine the effectiveness of different hemostatic factors in preventing excess hematoma expansion. METHODS: In C57BL/6 mice receiving 10 or 30 mg/kg rivaroxaban by gastric gavage, plasma concentration, prothrombin time, and coagulation factor activities were measured repeatedly. Thirty minutes after inducing ICH by intrastriatal collagenase-injection, mice received an intravenous injection of either saline, prothrombin complex concentrate (100 U/kg), murine fresh frozen plasma (200 μL), or recombinant human Factor VIIa (1 mg/kg). ICH volume was quantified on brain cryosections and using hemoglobin spectrophotometry 24 hours later. RESULTS: Rivaroxaban in 30 mg/kg dose substantially increased the hematoma volume in ICH induced by 0.060 U collagenase. Prothrombin complex concentrate, fresh frozen plasma, or Factor VIIa prevented excess hematoma expansion caused by anticoagulation. Prevention of hematoma expansion by prothrombin complex concentrate was dose-dependent. None of the 3 agents completely corrected the prolonged prothrombin time, although they restored the activities of deficient FII and X. CONCLUSIONS: Prothrombin complex concentrate, Factor VIIa, and fresh frozen plasma prevent excess intracerebral hematoma expansion in a murine ICH model associated with rivaroxaban. The efficacy and safety of this reversal strategy must be further evaluated in clinical studies.
[Show abstract][Hide abstract] ABSTRACT: Background: Klebsiella (K.) species is a commonly isolated gram-negative organism in sepsis and a frequent causative pathogen in pneumonia. It is associated with considerable morbidity and mortality. The receptor for advanced glycation end products (RAGE) plays a key role in diverse inflammatory responses. High mobility group box 1 (HMGB1) is a high-affinity ligand of RAGE.
Methods: We investigated the role of RAGE in the host response during K. pneumoniae pneumonia by intranasal inoculation of 1 x 104 colony forming units of viable Klebsiella bacteria in rage gene deficient (RAGE-/-) and normal wild-type (Wt) mice (n = 8-10 mice per genotype for each time point and n = 14 for survival studies). Mice were either euthanized at predefined time points or (in survival studies) monitored for 2 weeks. In a separate experiment, RAGE-/- and Wt mice intranasally received 100 μg highly pure lipopolysaccharide (LPS) derived from Klebsiella. For analysis of data, differences between groups were evaluated by Mann-Whitney U test. For survival analysis, Kaplan-Meier analysis was performed followed by a log-rank test. P values of <.05 were considered to represent a statistically significant difference.
Results: K. pneumoniae pneumonia resulted in an increased pulmonary expression of RAGE and its high-affinity ligand HMGB1 compared to healthy, uninfected mice. RAGE deficiency impaired host defense as reflected by a worsened survival, increased bacterial outgrowth and dissemination in RAGE deficient mice. RAGE-/- neutrophils showed a diminished phagocytosing capacity of live K. pneumoniae in vitro. RAGE-/- mice displayed an unaltered response to intranasally instilled KlebsiellaLPS.
Conclusion: The current study is the first to establish that RAGE is important for antibacterial defense against Klebsiella pneumonia. We here show that RAGE plays a protective role during respiratory tract infection by a common gram-negative causative pathogen, K. pneumoniae, by improving antibacterial defense in lungs and reducing bacterial dissemination. This could at least in part be explained by a better phagocytosis capacity of neutrophils in the presence of RAGE. Moreover, our results document that RAGE is not essential for the induction of excessive lung inflammation and injury.
IDWeek 2012 Meeting of the Infectious Diseases Society of America; 10/2012
[Show abstract][Hide abstract] ABSTRACT: Coagulation and complement regulators belong to two interactive systems constituting emerging mechanisms of diabetic nephropathy. Thrombomodulin (TM) regulates both coagulation and complement activation, in part through discrete domains. TM's lectin like domain dampens complement activation, while its EGF-like domains independently enhance activation of the anti-coagulant and cytoprotective serine protease protein C (PC). A protective effect of activated PC in diabetic nephropathy is established. We hypothesised that TM controls diabetic nephropathy independent of PC through its lectin-like domain by regulating complement. Diabetic nephropathy was analysed in mice lacking TM's lectin-like domain (TMLeD/LeD) and controls (TMwt/wt). Albuminuria (290 μg/mg vs. 166 μg/mg, p=0.03) and other indices of experimental diabetic nephropathy were aggravated in diabetic TMLeD/LeD mice. Complement deposition (C3 and C5b-9) was markedly increased in glomeruli of diabetic TMLeD/LeD mice. Complement inhibition with enoxaparin ameliorated diabetic nephropathy in TMLeD/LeD mice (e.g. albuminuria 85 μg/mg vs. 290 μg/mg, p<0.001). In vitro TM's lectin-like domain cell-autonomously prevented glucose-induced complement activation on endothelial cells and - notably - on podocytes. Podocyte injury, which was enhanced in diabetic TMLeD/LeD mice, was reduced following complement inhibition with enoxaparin. The current study identifies a novel mechanism regulating complement activation in diabetic nephropathy. TM's lectin-like domain constrains glucose-induced complement activation on endothelial cells and podocytes and ameliorates albuminuria and glomerular damage in mice.
Thrombosis and Haemostasis 09/2012; 108(6). · 5.76 Impact Factor
[Show abstract][Hide abstract] ABSTRACT: Ocular fundus photography allows detection of both ocular and systemic diseases. This study investigated the efficacy of a broad screening in a department of internal medicine using nonmydriatic digital fundus photography. For 8 weeks a medical technician was trained in using the camera as well as interpreting the photographs. The medical technician and an ophthalmologist evaluated the fundus photographs separately by using a self-developed questionnaire. The fundus camera was user-friendly and after several weeks of adjustment and practical application the medical technician was able to detect the majority of pathological fundus photographs. Out of 218 patients examined 148 (68%) were identified as pathological by the medical technician and 163 (75%) by the ophthalmologist (p = 0.0003). The medical technician missed 15 (7%) patients. Furthermore the diagnoses made by the medical technician were faulty. In summary an ophthalmological screening by a medical technician is feasible but the diagnosis still remains the responsibility of ophthalmologists. Such a compromise could facilitate the examination of a large number of patients and disclose previously unrecognized diseases.
[Show abstract][Hide abstract] ABSTRACT: PURPOSE: The purpose of this study was to evaluate changes in regional bone perfusion in Paget's disease (PD) following bisphosphonate therapy. We used dynamic contrast-enhanced MRI (DCE-MRI) for assessment of bone perfusion and compared MRI findings with alkaline phosphatase (AP) as a serum marker of bone turnover. MATERIALS AND METHODS: We examined 20 patients (8 women, 12 men, 66 ± 11 years) with symptomatic PD of the axial skeleton. Patients were selected for infusion therapy with the bisphosphonate pamidronate. The most affected bone of lumbar spine or pelvis was examined by DCE-MRI prior to therapy and after a 6-month follow-up. The contrast uptake was evaluated using a two-compartment model with the parameters amplitude A and exchange rate constant K(ep). Color-coded parametric images were generated to visualize bone vascularization. RESULTS: After a 6-month follow-up there was a significant decrease in alkaline phosphatase and in DCE-MRI parameters A and K(ep) (p < 0.0001). Patients without previous bisphosphonate treatment showed a significantly greater decrease in alkaline phosphatase and K(ep) (p < 0.001). CONCLUSION: DCE-MRI shows a significant reduction in regional bone perfusion in PD following parenteral bisphosphonate treatment. Reduction in bone perfusion is greater in bisphosphonate-naïve patients than in those who had been previously treated.
[Show abstract][Hide abstract] ABSTRACT: The receptor for advanced glycation endproduct (RAGE) is involved in diabetic complications and chronic inflammation, conditions known to affect the sensitivity towards apoptosis. Here, we studied the effect of genetically depleting RAGE on the susceptibility towards apoptosis. In murine osteoblastic cells, RAGE knockout increased both spontaneous and induced apoptosis. Decreased levels of B-cell lymphoma 2 protein and increased intrinsic apoptosis were observed in Rage(-/-) cells. Furthermore, loss of RAGE increased expression of the death receptor CD95 (Fas, Apo-1), CD95-dependent caspase activation and extrinsic apoptosis, whereas NF-kB-p65 nuclear translocation was diminished. Importantly, depletion of RAGE reduced the ubiquitination and degradation of p53 and p73 and increased their nuclear translocation. The increase of p53 and p73 transactivational activity was essential for the RAGE-dependent regulation of apoptosis, because knockdown of p53 and p73 significantly decreased apoptosis in RAGE-deficient but not in RAGE-expressing cells. Thus, the RAGE-mediated posttranslational regulation of p53 and p73 orchestrates a sequence of events culminating in control of intrinsic and extrinsic apoptosis signaling pathways.Oncogene advance online publication, 30 April 2012; doi:10.1038/onc.2012.150.
[Show abstract][Hide abstract] ABSTRACT: We hypothesised that diabetic patients would differ from those without diabetes in regard to the handling of glucose-derived reactive metabolites, evidenced by triosephosphate intermediates (TP(INT)) and methylglyoxal (MG), irrespective of the type of diabetes, plasma glucose level or HbA(1c) value.
To test this hypothesis, erythrocytes were isolated from patients with type 1 (n = 12) and type 2 (n = 12) diabetes with varying blood glucose and HbA(1c) levels. These were then compared with erythrocytes isolated from individuals without diabetes (n = 10), with respect to MG, as determined by HPLC, and TP(INT), as determined by endpoint enzymatic assays.
The concentrations of intracellular TP(INT) and MG were significantly elevated in erythrocytes from diabetic patients. Normalisation of either TP(INT) or MG to intracellular glucose concentration (nmol glucose/mgHb) confirmed that erythrocytes from diabetic patients accumulated more reactive metabolites than did those from healthy controls.
Diabetic patients can be characterised by an increased formation of TP(INT) and MG. The 25-fold increase of MG in type 1 and the 15-fold increase in type 2 diabetes, together with a several-fold increase in TP(INT) and decreased glyceraldehyde-3-phosphate dehydrogenase activity even under normal glucose conditions, imply that normalising glucose level cannot completely prevent late diabetic complications until this acquired error of metabolism has been restored.
[Show abstract][Hide abstract] ABSTRACT: A number of studies have addressed diabetic neuropathy (DN) in transgenic and knock out mouse models to unravel the molecular mechanisms underlying metabolic pain and loss of pain perception. However, it is difficult to compare these studies with each other or even with human DN due to experimental differences including the type of diabetes, the background strain of the respective mouse model, the methods of diabetes induction and the duration of diabetes, animal age and gender. To receive useful information for DN from genetically modified mice, it is therefore mandatory to first define the appropriate model and - if necessary - to backcross transgenic strains into the respective background to allow a reliable (and at least in part translatable to human DN) interpretation of the results.