Diabetes & Metabolism - In Press.Proof corrected by the author Available online since lundi 20 juin 2016

Background— Macrovascular complications of diabetes mellitus are a major risk factor for cardiovascular morbidity and mortality. Currently, studies only partially described the molecular pathophysiology of diabetes mellitus–associated effects on vasculature. However, better understanding of systemic effects is essential in unraveling key molecular events in the vascular tissue responsible for disease onset and progression. Methods and Results— Our overall aim was to get an all-encompassing view of diabetes mellitus–induced key molecular changes in the vasculature. An integrative proteomic and bioinformatics analysis of data from aortic vessels in the low-dose streptozotocin-induced diabetic mouse model (10 animals) was performed. We observed pronounced dysregulation of molecules involved in myogenesis, vascularization, hypertension, hypertrophy (associated with thickening of the aortic wall), and a substantial reduction of fatty acid storage. A novel finding is the pronounced downregulation of glycogen synthase kinase-3β (Gsk3β) and upregulation of molecules linked to the tricarboxylic acid cycle (eg, aspartate aminotransferase [Got2] and hydroxyacid-oxoacid transhydrogenase [Adhfe1]). In addition, pathways involving primary alcohols and amino acid breakdown are altered, potentially leading to ketone-body production. A number of these findings were validated immunohistochemically. Collectively, the data support the hypothesis that in this diabetic model, there is an overproduction of ketone-bodies within the vessels using an alternative tricarboxylic acid cycle-associated pathway, ultimately leading to the development of atherosclerosis. Conclusions— Streptozotocin-induced diabetes mellitus in animals leads to a reduction of fatty acid biosynthesis and an upregulation of an alternative ketone-body formation pathway. This working hypothesis could form the basis for the development of novel therapeutic intervention and disease management approaches.

Endothelial injury and dysfunction (ED) represent a link between cardiovascular risk factors promoting hypertension and atherosclerosis, the leading cause of death in Western populations. High-density lipoprotein (HDL) is considered antiatherogenic and known to prevent ED. Using HDL from children and adults with chronic kidney dysfunction (HDLCKD), a population with high cardiovascular risk, we have demonstrated that HDLCKD in contrast to HDLHealthy promoted endothelial superoxide production, substantially reduced nitric oxide (NO) bioavailability, and subsequently increased arterial blood pressure (ABP). We have identified symmetric dimethylarginine (SDMA) in HDLCKD that causes transformation from physiological HDL into an abnormal lipoprotein inducing ED. Furthermore, we report that HDLCKD reduced endothelial NO availability via toll-like receptor-2 (TLR-2), leading to impaired endothelial repair, increased proinflammatory activation, and ABP. These data demonstrate how SDMA can modify the HDL particle to mimic a damage-associated molecular pattern that activates TLR-2 via a TLR-1- or TLR-6-coreceptor-independent pathway, linking abnormal HDL to innate immunity, ED, and hypertension.

Representative animal models for diabetes-associated vascular complications are extremely relevant in assessing potential therapeutic drugs. While several rodent models for type 2 diabetes (T2D) are available, their relevance in recapitulating renal and cardiovascular features of diabetes in man is not entirely clear. Here we evaluate at the molecular level the similarity between Zucker diabetic fatty (ZDF) rats, as a model of T2D-associated vascular complications, and human disease by urinary proteome analysis. Urine analysis of ZDF rats at early and late stages of disease compared to age- matched LEAN rats identified 180 peptides as potentially associated with diabetes complications. Overlaps with human chronic kidney disease (CKD) and cardiovascular disease (CVD) biomarkers were observed, corresponding to proteins marking kidney damage (eg albumin, alpha-1 antitrypsin) or related to disease development (collagen). Concordance in regulation of these peptides in rats versus humans was more pronounced in the CVD compared to the CKD panels. In addition, disease-associated predicted protease activities in ZDF rats showed higher similarities to the predicted activities in human CVD. Based on urinary peptidomic analysis, the ZDF rat model displays similarity to human CVD but might not be the most appropriate model to display human CKD on a molecular level.

Background Patients with chronic kidney disease (CKD) exhibit a high cardiovascular morbidity and mortality, even in the early stages, and frequently develop hypertension. , Patients with advanced CKD have an uremic dyslipidemia, characterized by low levels of total cholesterol, low density lipoprotein and HDL cholesterol and elevated levels of triglycerides. In addition to its role in reverse cholesterol transport, HDL from healthy subjects (HS) exerts several potential vasoprotective effects. Thus, we compared endothelial effects of HDL from CKD patients and HS and potential consequences for blood pressure responses. Methods HDL was isolated from patients with CKD (K/DOQI stadium II, IV, V, each n=15) and healthy subjects (n=15) by sequential ultracentrifugation. The effect of HDL on endothelial nitric oxide production (NO) was assessed by electron spin resonance (ESR) spectroscopy. To evaluate the effects of HDL on systolic blood pressure (SBP) in vivo, HDL was injected into wild type and eNOS-deficient mice. Expression of VCAM-1 and endothelial mononuclear cell (MNC) adhesion was assessed. Moreover, endothelial repair capacity of HDL was assessed in vitro and vivo, using a gap closure assay and carotid injury model in nude mice . Results HDL from HS stimulated endothelial NO production; whereas HDL from CKD patients markedly inhibited the endothelial NO production (-80 % by HDL of these patients; P<0.05), even in incipient CKD. TLR2, but not TLR4 inhibition, prevented the inhibitory effects of HDLCKD on endothelial NO production. In vivo, CKD-HDL induced an increase of SBP (+10.7±1.1 mmHg; P<0.05), while healthy HDL reduced SBP (-11.3±1.7, P<0.05). Notably, HDL from patients with CKD induced endothelial VCAM-1 expression and promoted endothelial MNC adhesion, while HDL from healthy subjects did not. In vitro gap closure and in vivo reendothelialization after carotid injury were suppressed by HDL of CKD patients. Conclusion Our data demonstrate for the first time that endothelial-protective effects of HDL are considerably impaired in patients with CKD independently of the severity of CKD. Furthermore, HDL may be involved in initiation and aggravation of hypertension in these patients.

BACKGROUND:Arteriosclerosis and cardiovascular disease are strongly associated with vascular calcification. Hyperphosphatemia is an essential risk factor for increased vascular calcification. End-stage renal disease (ESRD) patients could serve as an in vivo model for accelerated calcification. This study focuses on the most likely protective effects of magnesium ion (Mg(2+)) on phosphate-induced vascular calcification ex vivo/in vitro. Furthermore, plasma Mg(2+) concentrations of ESRD and healthy controls were investigated for association with surrogate parameters of vascular calcification in vivo.METHODS:Aortic segments of male Wistar-Kyoto rats were incubated and the phosphate concentration of the medium was elevated. The aortic segments were incubated in the absence and presence of MgCl(2); tissue calcification was quantified by different methods. Serum Mg(2+) concentrations of patients with chronic kidney disease (CKD stage 5; ESRD) and patients without CKD (controls) were associated with carotid intima media thickness (IMT) and aortic pulse wave velocity (PWV) as surrogate parameter for arteriosclerosis and arterial stiffening.RESULTS:Incubation of aortic segments in the presence of β-glycerophosphate and NaH(2)PO(4) caused an increased tissue Ca(2+) deposition compared to control conditions. This increased amount of Ca(2+) in the aortic rings was significantly decreased in the presence of Mg(2+). In CKD patients, but not in controls, magnesium serum concentration was associated with the IMT of the carotid arteries. In addition, CKD patients with higher magnesium serum concentration had a significantly lower PWV.DISCUSSION AND CONCLUSION:Elevated phosphate concentrations in the culture media induce ex vivo/in vitro medial calcification in intact rat aortic rings in the presence of alkaline phosphatase. Mg(2+) ions reduced ex vivo/in vitro vascular calcification despite increased phosphate concentration. This hypothesis is additionally based on the fact that CKD patients with high Mg(2) serum levels had significantly lower IMT and PWV values, which may result in a lower risk for cardiovascular events and mortality in these patients. Therefore, Mg(2+) supplementation may be an option for treatment and prevention of vascular calcification resulting in a reduction of cardiovascular events in CKD patients.

Objectives The aim of this study was to investigate whether nebivolol has added effects on left ventricular (LV) dysfunction and remodeling early after myocardial infarction (MI) beyond its beta(1)-receptor-blocking properties.Background Nebivolol is a third-generation selective beta(1)-adrenoreceptor antagonist that stimulates endothelial cell nitric oxide (NO) production and prevents vascular reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase activation. Both endothelial NO synthase-derived NO production and NADPH oxidase activation are critical modulators of LV dysfunction early after MI.Methods Mice with extensive anterior MI (n = 90) were randomized to treatment with nebivolol (10 mg/kg/day), metoprolol-succinate (20 mg/kg/day), or placebo for 30 days starting on day 1 after surgery.Results Infarct size was similar among the groups. Both beta(1)-adrenergic receptor antagonists caused a similar decrease in heart rate. Nebivolol therapy improved endothelium-dependent vasorelaxation and increased early endothelial progenitor cells 4 weeks after MI compared with metoprolol and placebo. Nebivolol, but not metoprolol, inhibited cardiac NADPH oxidase activation after MI, as detected by electron spin resonance spectroscopy analysis. Importantly, nebivolol, but not metoprolol, improved LV dysfunction 4 weeks after MI (LV ejection fraction: nebivolol vs. metoprolol vs. placebo: 32 +/- 4% vs. 17 +/- 6% vs. 19 +/- 4%; nebivolol vs. metoprolol: p < 0.05) and was associated with improved survival 4 weeks post-MI compared with placebo. Nebivolol had a significantly more pronounced inhibitory effect on cardiomyocyte hypertrophy after MI compared with metoprolol.Conclusions Nebivolol improves LV dysfunction and survival early after MI likely beyond the effects provided by conventional beta(1)-receptor blockade. Nebivolol induced effects on NO-mediated endothelial function, early endothelial progenitor cells and inhibition of myocardial NADPH oxidase likely contribute to these beneficial effects of nebivolol early after MI. (J Am Coll Cardiol 2011;57:601-11) (C) 2011 by the American College of Cardiology Foundation

Tubulointerstitial fibrosis that results from renal tissue hypoxia is thought to be a key element of progressive chronic kidney diseases (CKD). Findings from epidemiological studies suggest that anemia in patients with CKD due to inadequate erythropoietin (EPO) secretion may contribute to progression. However, results of prospective controlled studies that evaluated the effect of recombinant human erythropoietin (rHuEPO) on the course of CKD were inconsistent. Nevertheless, slowing CKD progression with rHuEPO (and correction of anemia) may be achieved with a better understanding of the processes involved in the damage caused by renal tissue hypoxia.

AIMS Collateral arteries protect tissue from ischaemia. Heart rate correlates with vascular events in patients with arterial obstructive disease. Here, we tested the effect of heart-rate reduction (HRR) on collateral artery growth. METHODS AND RESULTS The I(f)-channel inhibitor ivabradine reduced heart rate by 11% in wild-type and 15% in apolipoprotein E (ApoE)(-/-) mice and restored endothelium-dependent relaxation in aortic rings of ApoE(-/-) mice. Microsphere perfusion and angiographies demonstrated that ivabradine did not change hindlimb perfusion in wild-type mice but improved perfusion in ApoE(-/-) mice from 40.5 ± 15.8-60.2 ± 18.5% ligated/unligated hindlimb. Heart rate reduction (13%) with metoprolol failed to improve endothelial function and perfusion. Protein expression of endothelial nitric oxide synthase (eNOS), phosphorylated eNOS, and eNOS activity were increased in collateral tissue following ivabradine treatment of ApoE(-/-) mice. Co-treatment with nitric oxide-inhibitor N (G)-nitro-L-arginine methyl ester abolished the effects of ivabradine on arteriogenesis. Following ivabradine, classical inflammatory cytokine expression was lowered in ApoE(-/-) circulating mononuclear cells and in plasma, but unaltered in collateral-containing hindlimb tissue, where numbers of perivascular macrophages also remained unchanged. However, ivabradine reduced expression of anti-arteriogenic cytokines CXCL10and CXCL11 and of smooth muscle cell markers smoothelin and desmin in ApoE(-/-) hindlimb tissue. Endothelial nitric oxide synthase and inflammatory cytokine expression were unchanged in wild-type mice. Ivabradine did not affect cytokine production in HUVECs and THP1 mononuclear cells and had no effect on the membrane potential of HUVECs in patch-clamp experiments. CONCLUSION Ivabradine-induced HRR stimulates adaptive collateral artery growth. Important contributing mechanisms include improved endothelial function, eNOS activity, and modulation of inflammatory cytokine gene expression.

Background: Collateral artery growth protects from ischemia. Heart rate correlates with vascular events in patients with arterial obstructive disease. Here, we tested the effects of heart rate redu...

Background Patients with chronic kidney disease (CKD) have a particularly high cardiovascular morbidity and mortality. High-density lipoprotein (HDL) from healthy subjects has been observed to exer...

Background Endothelial progenitor cells (EPCs) mediate vascular repair and regeneration. Their number in peripheral blood is related to cardiovascular events in individuals with normal renal function. Methods We evaluated the association between functionally active EPCs (cell culture) and traditional cardiovascular risk factors in 265 patients with chronic kidney disease stage V receiving hemodialysis therapy. Thereafter, we prospectively assessed cardiovascular events, e.g. myocardial infarction, percutaneous transluminal coronary angioplasty (including stenting), aorto-coronary bypass, stroke and angiographically verified stenosis of peripheral arteries, and cardiovascular death in this cohort. Results In our patients EPCs were related only to age (r = 0.154; p = 0.01). During a median follow-up period of 36 months 109 (41%) patients experienced a cardiovascular event. In a multiple Cox regression analysis, we identified EPCs (p = 0.03) and patient age (p = 0.01) as the only independent variables associated with incident cardiovascular events. Moreover, a total of 70 patients died during follow-up, 45 of those due to cardiovascular causes. Log rank test confirmed statistical significance for EPCs concerning incident cardiovascular events (p = 0.02). Conclusions We found a significant association between the number of functionally active EPCs and cardiovascular events in patients with chronic kidney disease. Thus, defective vascular repair and regeneration may be responsible, at least in part, for the enormous cardiovascular morbidity in this population.