Nicotine could augment adhesion molecule expression in human endothelial cells through macrophages secreting TNF-alpha, IL-1beta

Nicotine, the major immunomodulatory components of cigarette smoking, is among the leading risk factors in atherosclerosis and various other diseases. The subject of this study is to observe how nicotine affects the function of macrophages and vascular endothelial cells. The changes of nicotine on releasing of cytokines from Ana-1 were detected by radio-immunoassay (RIA) or enzyme-link immunosorbent assay (ELISA). The adhesion of monocytes to human umbilical vein endothelial cells (HUVECs) with Ana-1 supernatant-activated was evaluated through adhesion experiments. ELISA and RT-PCR methods examined expression of soluble adhesion molecular protein and their mRNA. Which cytokines in Ana-1 supernatant affecting HUVECs ability to express adhesion molecular were tested by adhesion blockade analysis and ELISA. The results showed TNF-alpha, IL-1beta could reach the peak with 0.06mM nicotine treated for 24 and 12 h on Ana-1, respectively, but IL-8 and IFN-gamma had no significant alter. Adhesion experiments proved treatment of HUVECs with supernatant of Ana-1 for 24 h obviously augmented the adhesion of monocytes to HUVECs. ELISA and PCR demonstrated expression of soluble intracellular adhesion molecule-1 protein (sICAM-1) increased sharply at 24 h, while soluble vascular cell adhesion molecule-1 protein (sVCAM-1) and soluble endothelial selectin protein (sE-selectin) rose at 9 h; ICAM-1, VCAM-1 and E-selectin mRNA had a similar tendency. Treatment of HUVECs with anti-TNF-alpha, anti-IL-1beta antibodies pre-neutralized supernatant of Ana-1 could block monocytes adhesion. In conclusion, our findings suggest that nicotine could augment macrophages releasing TNF-alpha and IL-1beta, furthermore TNF-alpha and IL-1beta could up-regulate the expression of adhesion molecule and increase adhesion of monocytes to HUVECs. These might be one of the reasons that leaded to endothelial dysfunction.