Objective-Hyperglycemia is the main determinant of long-term diabetic complications, mainly through induction of oxidative stress. NAD(P)H oxidase is a major source of glucose-induced oxidative stress. In this study, we tested the hypothesis that rosiglitazone (RSG) is able to quench oxidative stress initiated by high glucose through prevention of NAD(P)H oxidase activation. Methods and Results-Intracellular ROS were measured using the fluoroprobe TEMPO-9-AC in HUVECs exposed to control (5 mmol/L) and moderately high (10 mmol/L) glucose concentrations. NAD(P)H oxidase and AMPK activities were determined by Western blot. We found that 10 mmol/L glucose increased significantly ROS production in comparison with 5 mmol/L glucose, and that this effect was completely abolished by RSG. Interestingly, inhibition of AMPK, but not PPAR␥, prevented this effect of RSG. AMPK phosphorylation by RSG was necessary for its ability to hamper NAD(P)H oxidase activation, which was indispensable for glucose-induced oxidative stress. Downstream of AMPK activation, RSG exerts antioxidative effects by inhibiting PKC. Conclusions-This study demonstrates that RSG activates AMPK which, in turn, prevents hyperactivity of NAD(P)H oxidase induced by high glucose, possibly through PKC inhibition. Therefore, RSG protects endothelial cells against glucose-induced oxidative stress with an AMPK-dependent and a PPAR␥-independent mechanism. (Arterioscler

Objective-Endothelial progenitor cells (EPCs) participate in vascular homeostasis and angiogenesis. The aim of the present study was to explore EPC number and function in relation to cardiovascular risk, gender, and reproductive state. Methods and Results-As measured by flow-cytometry in 210 healthy subjects, CD34ϩ KDR ϩ EPCs were higher in fertile women than in men, but were not different between postmenopausal women and age-matched men. These gender gradients mirrored differences in cardiovascular profile, carotid intima-media thickness, and brachial artery flowmediated dilation. Moreover, EPCs and soluble c-kit ligand varied in phase with menstrual cycle in ovulatory women, suggesting cyclic bone marrow mobilization. Experimentally, hysterectomy in rats was followed by an increase in circulating EPCs. EPCs cultured from female healthy donors were more clonogenic and adherent than male EPCs. Treatment with 17␤-estradiol stimulated EPC proliferation and adhesion, via estrogen receptors. Finally, we show that the proangiogenic potential of female EPCs was higher than that of male EPCs in vivo. Conclusions-EPCs

Low expression of RGS2 contributes to increased G-protein-coupled signaling in hypertensive patients. The allele G is associated with low RGS2 expression and blood pressure increase in humans.

Oxidative stress plays a role in cardiovascular dysfunction. This is of interest in diabetes, a clinical condition characterized by oxidative stress and increased prevalence of cardiovascular disease. The role of p66(shc) in oxidative stress-related response has been demonstrated by resistance to and reduction of oxidative stress and prolonged lifespan in p66(shc-/-) mice. In this study we assess p66(shc) gene expression in peripheral blood mononuclear cells (PBM) from type 2 diabetic patients and healthy subjects. The p66(shc) mRNA level was assessed using RT-PCR with two sets of primers mapping for different p66(shc) regions. p66(shc) is expressed in both monocytes and lymphocytes. The level of p66(shc) mRNA was significantly higher in type 2 diabetic patients compared with controls (0.38 +/- 0.07 densitometric units vs. 0.13 +/- 0.08; P < 0.0001). In addition, total plasma 8-isoprostane levels, a marker of oxidative stress, were higher in type 2 diabetics (0.72 +/- 0.04 ng/ml) than in normal subjects (0.43 +/- 0.04, P < 0.001) and were significantly correlated to the p66(shc) mRNA level in PBM from type 2 diabetics (r(2) = 0.47; P = 0.0284). In conclusion, diabetes induces p66(shc) gene expression in circulating PBM; this up-regulation in expression is significantly associated with markers of oxidative stress. p66(shc) gene expression in PBM may represent a useful tool to investigate the oxidative stress involved in the pathogenesis of long-term diabetic complications.

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