Impaired vascular reactivity is present despite normal levels of von Willebrand factor in patients with uncomplicated Type 2 diabetes.

BACKGROUND: Type 2 diabetes is associated with an increased risk of cardiovascular disease. Endothelial dysfunction is thought to be an early marker of atherosclerosis. The purpose of this study was to assess whether endothelial function, judged by measurements of flow-mediated vasodilatation (FMD) and nitroglycerine (NTG)-induced vasodilatation as well as serum levels of von Willebrand factor, was affected in patients with uncomplicated Type 2 diabetes and normal levels of urinary albumin excretion (UAE). SUBJECTS AND METHODS: Twenty-three patients with Type 2 diabetes, normal UAE and no vascular complications were examined. Twenty-three healthy subjects matched for age, gender, body mass index and resting vessel size served as controls. All participants were non-smokers. Endothelial function was assessed by high-resolution ultrasound which measures changes in diameter of the brachial artery during flow-mediated and NTG-induced vasodilatation. We also measured serum levels of von Willebrand factor. RESULTS: In Type 2 diabetic patients FMD (3.2 +/- 0.5% vs. 4.8 +/- 0.5%, P = 0.019) as well as NTG-induced vasodilatation (15.9 +/- 0.6% vs. 18.5 +/- 0.9%, P = 0.021) were significantly reduced compared with controls. Levels of von Willebrand factor were not different between groups (0.88 +/- 0.07 vs. 0.88 +/- 0.07 in patients and controls, respectively) and were not correlated to FMD or NTG-induced vasodilatation. CONCLUSION: Impaired vascular reactivity is present in uncomplicated Type 2 diabetes and seems to be a more sensitive marker of vascular dysfunction than von Willebrand factor.