Alterations in vasodilation and the capacity of endothelium to release endothelial nitrogen monoxide,and its relationship with atherosclerosis in patients with diabetes mellitus

Objective To evaluate the association of vasodilation and endothelial nitrogen monoxide(NO)release with diabetic angiopathy.Methods Brachial artery diameter was measured at baseline,during postocclusion reactive hyperemia(flow-mediated endothelium-dependent),and after sublingual nitroglycerol(endothelium-independent)using a high resolution ultrasound technique in 20 control subjects and 62 patients with type 2 diabetes mellitus.Vasodilation was expressed as the percentage change relative to the baseline diameter.The capacity of vascular endothelium to release NO was examined by venous occlusion of the upper arm.Endothelial NO release was expressed as the percentage change relative to the baseline NO level.Intima-medial thickness of the right carotid artery was measured using ultrasound imaging.According to whether they had got coronary artery disease patients were divided into subgroups. Results There was no significant difference in endothelium-independent vasodilation between control subjects and diabetics(P0.05),there were significent reductions in endothelium-dependent vasodilation(P0.05),endothelial NO release(P0.01)and increase in intima-medial thickness of the carotid artery(P0.01)in diabetics compared with that in control subjects.In diabetics with coronary artery disease(CAD),endothelium-dependent and endothelium-independent vasodilation were significantly reduced compared with that in diabetics without CAD(P0.05,P0.01).There were no significant correlations between vasodilation and HbA1c,diabetes duration, endothelial NO release,intima-medial thickness in diabetics. Conclusions Endothelial vasodilation can be detected relative good using ultrasound technique in patients with diabetes mellitus.There are significant impaired endothelium-dependent vasodilation and endothelial NO release in patients with diabetes mellitus,which are related close to atherosclerosis.