Inhibitory effect of ghrelin on nicotine-induced VCAM-1 expression in human umbilical vein endothelial cells.

Endothelial dysfunction is thought to be a major cause of vascular injury in smokers. Ghrelin is a recently discovered peptide that plays a modulatory role in atherosclerosis. However, it is unknown how ghrelin regulates nicotine-induced vascular cell adhesion molecule-1 (VCAM-1) expression. We examined nicotine-induced VCAM-1 expression in human umbilical vein endothelial cells pretreated with ghrelin and detected the activity of protein kinase C (PKC), p38 mitogen-activated protein kinase (p38 MAPK), and nuclear factor (NF)-kappaB. Our study showed that ghrelin inhibited nicotine-induced VCAM-1 expression in human umbilical vein endothelial cells in a concentration-dependent and time-dependent way. We also found that ghrelin inhibited nicotine-induced PKC, p38 MAPK, and NF-kappaB activation. The results suggest that ghrelin inhibits nicotine-induced VCAM-1 expression, and PKC, p38 MAPK, and NF-kappaB play active roles in that process. Exogenous ghrelin may provide a possible approach for preventing or reversing atherosclerosis in smokers.