OBJECTIVETo determine whether advanced glycosylation end products modified bovine serum albumin (AGEs-BSA) affects endothelial cell lateral junction protein, platelet-endothelial cell adhesion molecule-1 (PECAM-1) in the presence or absence of inflammatory mediators.

METHODSCultured human umbilical vein endothelial cells (HUVECs) were exposed to AGEs-BSA for 6, 12, 24, and 36 hours, and exposed to AGEs-BSA glycosylated with different concentrations of glucose, tumor necrosis factor-alpha (TNF-alpha), interferon (IFN-gamma), TNF-alpha + IFN-gamma and AGEs-BSA + TNF-alpha for 24 hours, respectively. Expression of PECAM-1 mRNA was measured by semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) with beta-actin as an internal standard, and sequencing of RT-PCR products was performed to confirm the specificity of amplification for PECAM-1 gene. The endothelial cell surface expression of PECAM-1 was determined by flow cytometry (FCM).

RESULTSThere were no significant changes in the expression of PECAM-1 mRNA and protein when the cells were exposed to AGEs-BSA with different concentrations or periods (P > 0.05). However, PECAM-1 expression was reduced in the cells treated with TNF-alpha, IFN-gamma, TNF-alpha + IFN-gamma and AGEs-BSA + TNF-alpha. The level of PECAM-1 treated with AGEs-BSA + TNF-alpha was lower than that of TNF-alpha treated alone (P < 0.01).

CONCLUSIONSAGEs-BSA had no effect on the expression of PECAM-1 mRNA and protein in cultured HUVEC. With the presence of inflammatory mediator TNF-alpha, AGEs-BSA decreased the level of PECAM-1, which might reduce the adhesion interaction between adjacent endothelial cells, enhance the permeability of endothelial cells, and might be implicated in the endothelial dysfunction and pathogenesis of atherosclerosis in patients with diabetes mellitus. The significance of this phenomenon in intracellular signal transduction remains to be determined.