17Beta-estradiol inhibits the adhesion of leukocytes in TNF-alpha stimulated human endothelial cells by blocking IL-8 and MCP-1 secretion, but not its transcription

Inflammation, and especially mononuclear cell adhesion to endothelium, is an important physiopathological component of atherosclerosis. Since coronary heart disease in women of reproductive age and/or with estrogen replacement therapy is reduced, our aim was to determine if 17beta-estradiol had a regulatory effect on the adhesion of lymphocytes to the endothelium. We performed U-937 cells adhesion assays in TNF-alpha-stimulated HUVECs, and we also quantitated IL-8 and MCP-1 in culture supernatants, in the presence or not of 17beta-estradiol. The presence of alpha- and beta-estrogen receptors was determined by Western blot and RT-PCR, respectively, whereas the transcription of both chemokines was evaluated by RT-PCR. The results showed a 35% decrease in the adhesion of U-937 monocyte cells to TNF-alpha-stimulated HUVECs, and a 54% and 65% inhibition of TNF-alpha-induced IL-8 and MCP-1 secretion by physiological and physiologically high doses of 17beta-estradiol. The hormone did not affect the transcription of both chemokine genes. Tamoxifen reverted the inhibitory effect induced by 17beta-estradiol. In conclusion, 17beta-estradiol modifies the adhesion of leukocytes to endothelial cells by inhibiting the secretion, but not the gene transcription, of proinflammatory chemokines.