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 monocy tes to endothelial cells is observed in early atherosclerotic lesions. The aim of this study was to investigate the effects of 17 beta-estra diol (E-2) and progesterone on the adhesion of human monocytic THP-1 c ells to human female aortic endothelial cells (HAECs) in vitro. Minima lly oxidized low-density lipoprotein (LDL) significantly increased THP -1 cell adhesion to HAECs as compared with native LDL at the same conc entration. Though E-2 inhibited minimally oxidized LDL-induced THP-1 c ell adhesion in a dose-dependent manner, progesterone had no significa nt effects. Preincubation of HAECs with tamoxifen significantly antago nized the inhibitory effect of E-Z. These findings suggest a beneficia l effect of hormone replacement therapy on atherosclerosis.