Association between diabetic microangiopathy and vascular endothelial function evaluated by flow-mediated vasodilatation in patients with type 2 diabetes.

The main purpose of the study was to investigate the association between vascular endothelial function and diabetic microangiopathy (nephropathy, retinopathy and neuropathy) in patients with type 2 diabetes. In addition, the association between endothelial function and macroangiopathy evaluated by intimal-medial complex thickness (IMT) was also investigated. Endothelial function was evaluated non-invasively by the measurement of flow-mediated vasodilatation (FMD) of the brachial artery. Diabetic nephropathy and neuropathy were assessed by urinary albumin excretion (UAE) and motor or sensory nerve conduction velocity (MCV, SCV), respectively, and retinopathy was evaluated by an ophthalmologist using the Davis classification. FMD was measured in 102 patients with type 2 diabetes and in 20 control subjects, and showed a tendency to be lower in the diabetic patients. There was a significant decrease in FMD in patients with proliferative diabetic retinopathy, compared with those in patients with no diabetic retinopathy. FMD showed significant positive correlations with MCV and SCV, and significant negative correlations with log UAE, systolic blood pressure and diabetic duration, but no correlation was obtained between FMD and IMT. In stepwise regression analysis, MCV alone showed a significant association with FMD. In conclusion, our results show that in patients with type 2 diabetes FMD is closely associated with all types of microangiopathy, with neuropathy being most strongly associated with FMD; however, FMD is not associated with macroangiopathy evaluated by IMT.