Acetaldehyde stimulates monocyte adhesion in a P-selectin- and TNFα-dependent manner

ObjectiveThe aim of this study was to determine the effects of acetaldehyde on various steps of the monocyte recruitment cascade.MethodsHuman umbilical venous endothelial cells (HUVEC), primary blood monocytes (PBM) and THP-1 monocytes, were treated with acetaldehyde (0.1–0 μM) for 6 h. Monocyte adherence experiments were performed using 2′,7′-bis(2-carboxyethyl)-5,6-carboxyfluorescein-acetoxymethylester labeled PBM or 3H-thymidine labeled THP-1 cells. HUVEC TNFα mRNA and protein levels were determined by quantitative real-time PCR and immunoassay, respectively, and HUVEC P-selectin and monocyte CCR2 expression were determined by FACS analysis.ResultsAcetaldehyde dose-dependently increased the number of CCR2 positive THP-1 monocytes, with a maximal increase of ∼50% observed in the presence of 10 μM acetaldehyde. There was a significant increase in both the number of P-selectin positive cells and P-selectin receptor density when HUVEC were incubated with acetaldehyde. HUVEC TNFα mRNA expression and secretion were enhanced by acetaldehyde. Moreover, acetaldehyde increased THP-1 and PBM adhesion to HUVEC. Inhibition of P-selectin or TNFα, using antibodies or siRNA-directed gene knockdown, attenuated acetaldehyde-induced monocyte adhesion. In conclusion, acetaldehyde increased the number of CCR2 positive monocytes and stimulated endothelial cell P-selectin and TNFα expression. Moreover, acetaldehyde increased monocyte adhesion to endothelial cells, an effect that was both P-selectin- and TNFα-dependent.ConclusionThese effects of acetaldehyde may contribute, in part, to the increase in coronary heart disease that is associated with binge patterns of alcohol consumption.