Effects of 17 beta-estradiol and progesterone on the adhesion of human monocytic THP-1 cells to human female endothelial cells exposed to minimally oxidized LDL

It is known that hormone replacement therapy inhibits the progression of atherosclerosis in postmenopausal women. Focal attachment of monocytes to endothelial cells is observed in early atherosclerotic lesions. The aim of this study was to investigate the effects of 17 beta-estradiol (E-2) and progesterone on the adhesion of human monocytic THP-1 cells to human female aortic endothelial cells (HAECs) in vitro. Minimally oxidized low-density lipoprotein (LDL) significantly increased THP-1 cell adhesion to HAECs as compared with native LDL at the same concentration. Though E-2 inhibited minimally oxidized LDL-induced THP-1 cell adhesion in a dose-dependent manner, progesterone had no significant effects. Preincubation of HAECs with tamoxifen significantly antagonized the inhibitory effect of E-Z. These findings suggest a beneficial effect of hormone replacement therapy on atherosclerosis.