Differential glucose uptake in retina- and brain-derived endothelial cells

Microangiopathy is a systemic complication of diabetes that is especially s evere in the retinal microcirculation. The objective of this study was to c ompare glucose uptake and glucose transporter expression between retinal en dothelial cells and the closely related endothelial cells derived from the cerebral microcirculation. Endothelial cells isolated from bovine brain, bo vine retinal, and rat heart microvessels were cultured in the presence of c ontrol (5 mM) and high levels of (30 MM) D-glucose for 1-5 days. Glucose up take by cultured endothelial cells was determined by measuring the uptake o f [H-3]deoxy-D-glucose and glucose transporter protein expression was asses sed by Western blot. Our results showed that glucose uptake was significant ly (P < 0.001) higher in brain- and heart-derived endothelial cells than in retinal endothelial cells at both physiologic and high concentrations of g lucose. High levels of glucose caused a significant (P < 0.05) decrease in glucose uptake in brain-derived and heart endothelial cells but had no effe ct on retinal endothelial cells. Similarly, in response to high glucose lev els there was a significant (P < 0.01) down regulation of GLUT-1 in brain-d erived endothelial cells but not in retinal endothelial cells. These result s suggest that despite a low basal level of glucose uptake the inability of retinal endothelial cells to down regulate glucose uptake in the presence of high glucose levels could make them especially sensitive to the deleteri ous effects of hyperglycemia in diabetes. (C) 2001 Academic Press.