Effect of High Glucose Concentration on Expression of Adhesion Molecules in Endothelial Cells

Kim, In Ju; Son, Seok Man; Lee, Min Ki; Jeong, Hee; Kim, Yong Ki

Abstract

BACKGROUND: Accelerated atherosclerotic vascular disease is the leading cause of mortality in patients with diabetes mellitus. Endothelial dysfunction, monocytes, and platelets are well known pathogenic factors in atherogenesis. Changes in the neutrophils and endothelial cells, an important early events in all inflammatory process, may contribute to the atherogenesis at early stage, but the significance of this process is not established yet. So we investigated the effects of glucose on the expression of adhesion molecules in endothelial cells, which retlects the change in endothelial-neutrophil adhesive interactions.METHODS: The human umbilical vein endothelial cells(HUVECs) are purchased from American Type Culture Collection. The cells were incubated upto 24 hours to evaluate the expression of E-selectin, PECAM-1, and P-selectin on the cell surface using whole cell ELISA method and soluble P-selectin under different glucose concentration(5.5, 15, and 30 mmol/L). Neutrophil adherence was also measured hy incubation of isolated human neutrophils with monolayers of HUVECs under same different glucose concentration. RESULTS: After 24h incubation with a various concentration of glucose, neutrophil adherence to high concentration of glucose(15 and 30mmol/L)- treated endothelium was significantly increased(5.0 +0.4 and 10.4+0.5%, respectively) compared with adhesion to low concentration of glucose(5.5mmol/ L)-treated endothelium(2.9.+0.4%). Incubation of HUVECs for 24 h in 30mmol/L glucose increased absorbance of E-selectin to 1.36+0.16(P<0.01) and reduced that of P-selectin to 0.56+0.04 compared with the results of respective control culture in 5.5mmol/L glucose(p<0.01), but not changed PECAM-1 expression. In addition, 24 h exposure of HUVECs to 30mmol/L glucose decreased soluble P-selectin concentration to 0.33+0.06ng/mL(P<0.01). CONCLUSION: The results of this study demonstrate that high concentration of glucose stimulates neutrophil adhesion to endothelial cells in association with increased expression of E-selectin. These results suggest that high glucose can directly affect interaction between neutrophil and endothelial cell through a adhesion molecule, especially E-selectin dependent mechanism. Further study should be necessary to investigate the significance of this phenomenon.