Nitric oxide mediates hyperglycemia-induced defective migration in cultured endothelial cells

Purpose: To examine the effects of elevated glucose on the migration and proliferation of vascular endothelial cells in an in vitro wound model and to investigate whether nitric oxide (NO) mediates the effects of elevated glucose. Methods: Migration was investigated in monolayers of bovine aortic endothelial cells wounded by scraping and measuring the distance, the number of cells migrating, and the area covered by the migrating cells in the presence of various concentrations of glucose. The effects of NO were evaluated by adding to the cultures NG-monomethyl arginine (NMMA), an inhibitor of NO synthase, or S-nitrosylated penicillamine, which is a slow-release agent of NO. Proliferation was investigated in the presence of various concentrations of serum, glucose, or both. Results: Elevated glucose levels (16.5 and 27.7 mmol/L) inhibited endothelial cell migration in a dose-dependent manner compared with cells cultured in the presence of 5.5 mmol/L glucose. Inhibition of migration was also observed when wounded monolayers cultured in 5.5 mmol/L glucose were treated with S-nitrosylated penicillamine, which generates NO. Inhibition of NO synthase by NMMA prevented the inhibition of migration observed in media containing 27.7 mmol/L glucose. Elevated glucose levels did not affect cell proliferation except in the presence of 20% fetal bovine serum. Conclusion: An elevated glucose level inhibits endothelial cell migration in an in vitro wound model, and the inhibition appears to be mediated by increased levels of NO.