Influence of insulin and glargine on outgrowth and number of circulating endothelial progenitor cells in type 2 diabetes patients: a partially double-blind, randomized, three-arm unicenter study.

BACKGROUND: Endothelial progenitor cells (EPC) are bone marrow-derived cells which can undergo differentiation into endothelial cells and participate in endothelial repair and angiogenesis. Insulin facilitates this in vitro mediated by the IGF-1 receptor. Clinical trials showed that the number of circulating EPCs is influenced by glucose control and EPC are a predictor of cardiovascular death. To study direct effects of insulin treatment on EPCs in type 2 diabetes patients, add-on basal insulin treatment was compared to an escalation of oral medication aiming at similar glucose control between the groups. METHODS: 55 patients with type 2 diabetes (61.6±5.9 years) on oral diabetes medication were randomized in a 2:2:1 ratio in 3 groups. Patients were treated additionally with insulin glargine (n=20), NPH insulin (n=22) or escalated with oral medication (n=13). Number of circulating EPC, EPC-outgrowth, intima media thickness, skin microvascular function and HbA1c were documented at baseline and/or after 4 weeks and 4 months. RESULTS: HbA1c at baseline was, 7.3+/-0.7% in the oral group, 7.3+/-0.9% and 7.5+/-0.7% in the glargine and NPH insulin respectively (p=0.713). HbA1c after 4 months decreased to 6.8+/-0.8%, 6.6+/-0.7% and 6.7+/-0.6%, in the oral, glargine and NPH insulin group respectively (p=0.61). FACS analysis showed no difference in number of circulating EPC between the groups after 4 weeks and 4 months. However, the outgrowth of EPCs as detected by colony forming assay was increased in the NPH insulin and glargine groups (29.2+/-6.4 and 29.4+/- 6.7 units respectively) compared to the group on oral medication (23.2+/-6.3, p=0.013) after 4 months of treatment. A significant decrease of IMT from 0.80mm (+/-0.14) at baseline to 0.76mm (+/-0.12) after 4 months could be observed in all patients only (p=0.03) with a trend towards a reduction of IMT after 4 months when all patients on insulin treatment were compared to the oral treatment group (p=0.06). Skin microvascular function revealed no differences between the groups (p=0.74). CONCLUSION: The study shows that a 4-month treatment with add-on insulin significantly increases the outgrowth of EPC in patients with type 2 diabetes mellitus. TRIAL REGISTRATION: (Clinical Trials Identifier: NCT00523393).

Targeting activation of specific NF-κB subunits prevents stress-dependent atherothrombotic gene expression.

Psychosocial stress has been shown to be a contributing factor in the development of atherosclerosis. Although the underlying mechanisms have not been elucidated entirely, it has been shown previously that the transcription factor nuclear factor-κB (NF-κB) is an important component of stress-activated signaling pathway. In this study, we aimed to decipher the mechanisms of stress-induced NF-κB-mediated gene expression, using an in vitro and in vivo model of psychosocial stress. Induction of stress led to NF-κB-dependent expression of proinflammatory (tissue factor, intracellular adhesive molecule 1 [ICAM-1]) and protective genes (manganese superoxide dismutase [MnSOD]) via p50, p65 or cRel. Selective inhibition of the different subunits and the respective kinases showed that inhibition of cRel leads to the reduction of atherosclerotic lesions in apolipoprotein(-/-) (ApoE(-/-)) mice via suppression of proinflammatory gene expression. This observation may therefore provide a possible explanation for ineffectiveness of antioxidant therapies and suggests that selective targeting of cRel activation may provide a novel approach for the treatment of stress-related inflammatory vascular disease.

Soluble RAGE but not endogenous secretory RAGE is associated with albuminuria in patients with type 2 diabetes.

BACKGROUND: Total circulating soluble receptor for advanced glycation endproducts (sRAGE) and a more defined endogenous secretory splice variant of the receptor (esRAGE) were shown to be associated with different markers of cardiovascular risk in patients with diabetes. Since previous data were partly divergent, the aim of this study was to compare sRAGE and esRAGE in a head-to-head analysis in patients with type 2 diabetes (T2DM) with albuminuria. METHODS: sRAGE and esRAGE were studied in plasma of 110 T2DM patients using enzyme-linked immunosorbant assays (ELISA) detecting either sRAGE or esRAGE only. Both sRAGE and esRAGE were compared with regard to applicability as markers for vascular disease and glucose control in T2DM. RESULTS: In bivariate analysis, sRAGE correlated with age (R = 0.22, p = 0.02) and the 24 hour albumin excretion rate (R = 0.18, p = 0.05), while esRAGE correlated positively with age only (R = 0.23, p = 0.02). In contrast to previous reports, neither sRAGE nor esRAGE correlated with glucose control or intima-media-thickness (IMT) as a predictor of macrovascular disease. In multivariate regression models, the associations between sRAGE and albuminuria as well as esRAGE and age were shown to be independent of glucose control, diabetes duration, body-mass index, glomerular filtration rate, blood pressure and gender. CONCLUSION: This is the first study comparing sRAGE and esRAGE as markers of vascular complications in patients with T2DM. sRAGE but not esRAGE is independently associated with albuminuria in these patients while neither sRAGE nor esRAGE are associated with markers of glucose control or macrovascular disease.

Integrated Personalized Diabetes Management (PDM): Design of the ProValue Studies: Prospective, Cluster-Randomized, Controlled, Intervention Trials for Evaluation of the Effectiveness and Benefit of PDM in Patients With Insulin-Treated Type 2 Diabetes.

BACKGROUND: Collaborative use of structured self-monitoring of blood glucose (SMBG) data and data management software, utilized within a 6-step cycle enables integrated Personalized Diabetes Management (PDM). The 2 PDM-ProValue studies shall assess the effectiveness of this approach in improving patient outcomes and practice efficiencies in outpatient settings. METHODS: The PDM-ProValue studies are 12-month, prospective, cluster-randomized, multicenter, trials to determine if use of integrated PDM in daily life improves glycemic control in insulin-treated type 2 diabetes patients. Fifty-four general medical practices (GPs) and 36 diabetes-specialized practices (DSPs) across Germany will be recruited. The practices will be randomly assigned to the control groups (CNL) or the intervention groups (INT) via cluster-randomization. CNL practices will continue with their usual care; INT practices will utilize integrated PDM. The sample size is 1,014 patients (n = 540 DSP patients, n = 474 GP patients). Each study is designed to detect a between-group difference in HbA1c change of at least 0.4% at 12 months with a power of 90% and 2-sided significance level of .05. Differences in timing and degree of treatment adaptions, treatment decisions, blood glucose target ranges, hypoglycemia, self-management behaviors, quality of life, patients attitudes, clinician satisfaction, practice processes, and resource consumption will be assessed. Study endpoints will be analyzed for the modified intent-to-treat and per protocol populations. Trial results are expected to be available in late 2016. DISCUSSION: Effective and efficient strategies to optimize diabetes management are needed. These randomized studies will help determine if PDM is beneficial.

Identical LDL-cholesterol lowering but non-identical effects on NF-κB activity: High dose simvastatin vs combination therapy with ezetimibe.

OBJECTIVE: Lowering LDL-cholesterol by statins has been proven to be associated with reduction of proinflammatory regulators e.g. activation of the transcription factor NF-κB. To our knowledge, anti-inflammatory potential of newer cholesterol lowering agents such as ezetimibe is less intensively studied. Therefore we analyzed the effects of equipotent LDL-lowering therapy with simvastatin alone compared to a combination with ezetimibe on NF-κB activation in peripheral blood mononuclear cells (PBMCs) of patients with type 2 diabetes. METHODS: Thirty-one patients with type 2 diabetes were included in a double-blind, randomized trial receiving either 80 mg simvastatin (sim80; n = 10) or a combination of 10 mg simvastatin and 10 mg ezetimibe (sim10eze10; n = 11) or placebo (n = 9) for eight weeks. NF-κB binding activity and inflammatory markers (IL-6, hsCRP) were analyzed at baseline and after eight weeks of treatment. NF-κB binding activity was analyzed by electrophoretic mobility shift assay. IL-6 and hsCRP were measured by ELISA. RESULTS: After eight weeks of treatment LDL-cholesterol was lowered to the same extent in both treatment groups (p = 0.40) but not in placebo. However, patients taking sim80 showed a significant reduction of mononuclear NF-κB binding activity compared to baseline (p = 0.009) while no effect was observed in the sim10eze10 group (p = 0.79). Similar differences in anti-inflammatory effects were also observed when analyzing hsCRP (sim80: p = 0.03; sim10eze10: p = 0.40) and IL-6 levels (sim80: p = 0.15; sim10eze10: p = 0.95). CONCLUSION: High dose simvastatin therapy reduces proinflammatory transcription factor NF-κB binding activity and hsCRP levels, while combination of low dose simvastatin with ezetimibe resulting in a similar LDL-reduction does not affect these inflammatory markers.

Sustained effects of a mindfulness-based stress-reduction intervention in type 2 diabetic patients: design and first results of a randomized controlled trial (the Heidelberger Diabetes and Stress-study).

OBJECTIVE: To determine whether a mindfulness-based stress reduction (MBSR) intervention is effective for reducing psychosocial distress (i.e., depression, psychosocial stress) and the progression of nephropathy (i.e., albuminuria) and for improving the subjective health status of patients with type 2 diabetes. RESEARCH DESIGN AND METHODS: Patients with type 2 diabetes and microalbuminuria were randomized to a mindfulness-based intervention (n = 53) or a treatment-as-usual control (n = 57) group. The study is designed to investigate long-term outcomes over a period of 5 years. We present data up to the first year of follow-up (FU). RESULTS: At FU, the MBSR group showed lower levels of depression (d = 0.71) and improved health status (d = 0.54) compared with the control group. No significant differences in albuminuria were found. Per-protocol analysis also showed higher stress reduction in the intervention group (d = 0.64). CONCLUSIONS: MBSR intervention achieved a prolonged reduction in psychosocial distress. The effects on albuminuria will be followed up further.

Association of homozygous SDF-1 3'A genotype with proliferative diabetic retinopathy.

Stromal cell-derived factor 1 (SDF-1) is involved in the development of experimental proliferative retinopathy. Since little data are available on the genetic predisposition or on biomarkers predicting the development of proliferative retinopathy, we assessed the distribution of the SDF-1 3'A genotype in 130 diabetic patients with retinopathy. In patients with proliferative retinopathy, the frequency of the homozygous SDF-1 3'A genotype was significantly higher than in patients with non-proliferative retinopathy (10.9% of PDR vs. 0 of NPDR, P = 0.01). This association was confirmed when type 2 diabetes patients were analysed separately (10.3% of PDR vs. 0 of NPDR, P = 0.03). The finding that homozygous carriers of the SDF-1 3'A genotype are more frequent in diabetes patients with proliferative retinopathy suggests a possible role of this genotype in the development of sight-threatening diabetic retinopathy.

A non-enzymatic function of 17beta-hydroxysteroid dehydrogenase type 10 is required for mitochondrial integrity and cell survival.

Deficiency of the mitochondrial enzyme 2-methyl-3-hydroxybutyryl-CoA dehydrogenase involved in isoleucine metabolism causes an organic aciduria with atypical neurodegenerative course. The disease-causing gene is HSD17B10 and encodes 17beta-hydroxysteroid dehydrogenase type 10 (HSD10), a protein also implicated in the pathogenesis of Alzheimer's disease. Here we show that clinical symptoms in patients are not correlated with residual enzymatic activity of mutated HSD10. Loss-of-function and rescue experiments in Xenopus embryos and cells derived from conditional Hsd17b10(-/-) mice demonstrate that a property of HSD10 independent of its enzymatic activity is essential for structural and functional integrity of mitochondria. Impairment of this function in neural cells causes apoptotic cell death whilst the enzymatic activity of HSD10 is not required for cell survival. This finding indicates that the symptoms in patients with mutations in the HSD17B10 gene are unrelated to accumulation of toxic metabolites in the isoleucine pathway and, rather, related to defects in general mitochondrial function. Therefore alternative therapeutic approaches to an isoleucine-restricted diet are required.

Insulin stimulates the clonogenic potential of angiogenic endothelial progenitor cells by IGF-1 receptor-dependent signaling.

Endothelial progenitor cells (EPCs) have been shown to be involved in vascular regeneration and angiogenesis in experimental diabetes. Because insulin therapy mobilizes circulating progenitor cells, we studied the effects of insulin on outgrowth of EPCs from peripheral blood mononuclear cells of healthy volunteers and patients with type 2 diabetes. Insulin increased the formation of EPC colony-forming units in a dose-dependent manner, half-maximal at 1.5 nM and peaking at 15 nM. Inhibiting the insulin receptor with neutralizing antibodies or antisense oligonucleotides had no effect on EPC outgrowth.(1) In contrast, targeting the human insulin-like growth factor 1 (IGF-1) receptor with neutralizing antibodies significantly suppressed insulin-induced outgrowth of EPCs from both healthy controls and patients with type 2 diabetes. This IGF-1 receptor-mediated insulin effect on EPC growth was at least in part dependent on MAP kinases(2) and was abrogated when extracellular signal-regulated kinase 1/2 (Erk1/2) and protein kinase 38 (p38) activity was inhibited. To study the functional relevance of the observed insulin effects, we studied EPC-induced tube formation of bovine endothelial cells in vitro. Insulin-stimulated EPCs incorporated into the endothelial tubes and markedly enhanced tube formation. In conclusion, this is the first study showing an insulin-mediated activation of the IGF-1 receptor leading to an increased clonogenic and angiogenic potential of EPCs in vitro.

Chronic corticosterone-induced deterioration in rat behaviour is not paralleled by changes in hippocampal NF-kappaB-activation.

We investigated whether long-lasting stress induced by chronic glucocorticoid (GC) exposure affects activation of brain NF-kappaB and whether these changes are related to functional deterioration and structural changes in the rat hippocampus. Psychometric investigations were conducted using a holeboard test system in 28 one-year-old male Wistar rats. Thereafter, rats were divided into three groups for daily administration of 10 mg corticosterone (treatment) or sesame oil (placebo = sham control for effects of the vehicle) for 60 days. Additional control rats did not receive any treatment or handling until the end of the experiment. Behavioural and cognitive changes were tested again in the holeboard system. Rat body weights and corticosterone concentrations in plasma, hippocampus and urine were determined and adrenal glands were investigated histopathologically. Hippocampal concentrations of corticosterone, NF-kappaB and I-kappaBalpha were determined using RIA, EMSA and Western blotting techniques, respectively. Structural changes in rat hippocampus were measured using magnetic resonance imaging techniques. High peripheral corticosterone concentrations after chronic treatment led to significant reductions in rat body weight. Significant atrophy of both adrenal glands with marked histological deterioration was detected. Furthermore, an increase in hippocampal corticosterone concentrations was observed after chronic administration. Chronic corticosterone treatment also significantly altered behaviour and working and reference memory capacity without changing hippocampal structure. Daily injections of sesame oil in the placebo group, however, were also sufficient to reduce the pellet-finding time. However, neither in the corticosterone group nor in the placebo group were behavioural changes paralleled by significant changes in brain NF-kappaB activation and I-kappaBalpha expression. Thus, cognitive alterations in rats seen after chronic corticosterone exposure are not paralleled by hippocampal NF-kappaB modulation.