Glucose fluctuation on the progression of diabetic macroangiopathy--new findings from monocyte adhesion to endothelial cells.

The aim of this study was to elucidate the effect of repetitive fluctuations in blood glucose concentrations on monocyte adhesion to the aortic endothelium. Streptozotocin induced diabetes rats were fed twice daily to induce repetitive postprandial glucose spikes. Then, we compared the number of monocytes adherent to the endothelium of thoracic aorta in these rats with that in rats fed ad libitum. In addition, we evaluated the effect of N-acetyl-L cystein and probucol which are known as antioxidants on the monocyte adhesion to endothelial cells. Streptozotocin induced diabetes rats fed twice daily showed remarkably lower HbA(1c) than the rats fed ad libitum. However, the former group showed markedly higher number of monocytes adherent to the endothelium than the latter. Both N-acetyl-L cystein and probucol could not reduce the number of adherent monocytes in streptozotocin induced diabetes rats fed twice daily. Our data demonstrated that repetitive postprandial fluctuation in glucose concentration evokes monocyte adhesion to endothelial cells that was worse than that induced by stable hyperglycemia in vivo.