Acute Hyperglycemia Induces Endothelial Dysfunction

Type 2 diabetes is associated with many complications at the macro- and microvascular level. The impact of acute hyperglycemia on retinal as well as macrovascular circulation was investigated in a recent study. Vascular and endothelial function assessments included retinal vascular reactivity and flow-mediated dilatation of the brachial artery measured at fasting and at hyperglycemic state. Acute hyperglycemia was simulated by oral glucose tolerance test (OGTT) and assessments were done at 1, 2, 3 and 4 hours post-OGTT. Relative to baseline, mean flow-mediated dilatation decreased in patients with type 2 diabetes at 1 and 2 hours post-OGTT but started to recover at 3 hours. In the same group, postprandial retinal vessel reactivity increased and persisted up to 3 hours post-OGTT. These alterations were not evident in the control group. The study demonstrated how acute hyperglycemia can induce changes in macro- and microcirculation that leads to endothelial dysfunction and altered blood flow in the retina. These findings have some implications on the pathogenesis of diabetic macro- and microvascular complications including cardiovascular disease and diabetic retinopathy Chittari, M.V. et al. Diabet Med 2011, 28(4): 450.