No abstract

T ype 2 diabetes mellitus (T2DM) is associated with increased risk of micro and macrovascular complications and ≈2-fold greater risk of mortality when compared with the general population.1,2 Advances in therapy have reduced morbidity and mortality in patients with T2DM. However, cardiovascular risk is far to be eradicated, and mechanism-based therapeutic approaches are needed. 3,4 In patients with diabetes mellitus, high-glucose levels trigger endothelial inflammation, mitochondrial oxidative stress, and reduced availability of nitric oxide, a key effector of vascular health. 3,5 This chain of events favors the development of coronary atherosclerotic lesions, as well as microvascular disease. 4 Although the link between diabetes mellitus and atherosclerosis is well established, a better comprehension of the underlying mechanisms is of utmost importance to identify novel molecular targets. Epigenetic modifications are emerging as key players in cardiovascular disease.6 Acetylation and methylation occurring at DNA/histone complexes significantly alter gene transcription Background-Cellular studies showed that histone methyltransferase Set7 mediates high glucose-induced inflammation via epigenetic regulation of the transcription factor NF-kB. However, the link between Set7 and vascular dysfunction in patients with diabetes mellitus remains unknown. This study was designed to investigate whether Set7 contributes to vascular dysfunction in patients with type 2 diabetes mellitus (T2DM). Methods and Results-Set7-driven epigenetic changes on NF-kB p65 promoter and expression of NF-kB-dependent genes, cyclooxygenase 2 and inducible endothelial nitric oxide synthase, were assessed in peripheral blood mononuclear cells isolated from 68 subjects (44 patients with T2DM and 24 age-matched controls). Brachial artery flow-mediated dilation, 24-hour urinary levels of 8-isoprostaglandin F 2α , and plasma adhesion molecules, intercellular cell adhesion molecule-1 and monocyte chemoattractant protein-1, were also determined. Experiments in human aortic endothelial cells exposed to high glucose were performed to elucidate the mechanisms of Set7-driven inflammation and oxidative stress. Set7 expression increased in peripheral blood mononuclear cells from patients with T2DM when compared with controls.Patients with T2DM showed Set7-dependent monomethylation of lysine 4 of histone 3 on NF-kB p65 promoter. This epigenetic signature was associated with upregulation of NF-kB, subsequent transcription of oxidant/inflammatory genes, and increased plasma levels of intercellular cell adhesion molecule-1 and monocyte chemoattractant protein-1. Interestingly, we found that Set7 expression significantly correlated with oxidative marker 8-isoprostaglandin F 2α (r=0.38; P=0.01) and flow-mediated dilation (r=−0.34; P=0.04). In human aortic endothelial cells, silencing of Set7 prevented monomethylation of lysine 4 of histone 3 and abolished NF-kB-dependent oxidant and inflammatory signaling. Conclusions-Set7-induced epigenetic changes contribute to...

Pin1 drives diabetic vascular disease by causing mitochondrial oxidative stress, eNOS dysregulation as well as NF-kB-induced inflammation. These findings provide molecular insights for novel mechanism-based therapeutic strategies in patients with diabetes.

Short-acting nitrates improve EST results in CAD, but not in MVA patients. In MVA patients a lower nitrate-dependent coronary microvascular dilation may contribute to the lack of effects of nitrates on EST results.