Association Between Diabetic Retinopathy and Flow-Mediated Vasodilation in Type 2 DM

OBJECTIVE: Retinal endothelial dysfunction is a key in the etiogenesis of diabetic retinopathy (DR), in patients with type 2 diabetes mellitus (DM). Brachial artery flow-mediated vasodilation (FMD) is a marker of endothelial function associated with production of endogenous nitric oxide. Using FMD, we investigated the relationship between macrovascular function and DR. METHODS: We studied 74 patients with type 2 DM, including non-DR (NDR) (n = 30); mild nonproliferative DR (NPDR) (n = 16); moderate NPDR (n = 10); severe NPDR (n = 10); and proliferative DR (PDR) (n = 8); and 21 age-matched controls. We measured FMD in each group. Retinal blood flow and pulsatility ratios were measured using laser Doppler velocimetry. RESULTS: FMD decreased significantly in patients with DM compared with healthy control subjects. No significant differences were found in FMD among the NDR, mild NPDR, and moderate NPDR groups. FMD decreased significantly in the severe NPDR and PDR groups compared with the NDR group. FMD was significantly and negatively correlated with duration of DM and pulsatility ratio. CONCLUSION: Systemic endothelial dysfunction appears to be associated with DR and vascular abnormalities in patients with type 2 DM.