Estrogen regulation of endothelial and smooth muscle cell migration and proliferation - Role of p38 and p42/44 mitogen-activated protein kinase

Objective-Restenosis is a major limitation of percutaneous coronary intervention. Migration and proliferation of vascular cells remain a cornerstone in neointimal formation. The cardioprotection of estrogen is well recognized, but the intracellular mechanisms related to these beneficial effects are not completely understood. Methods and Results-We investigated the effects of 17beta-estradiol (17betaE) on mitogen-activated protein kinase (MAPK) activity and the migration and proliferation of porcine aortic endothelial cells (PAECs) and porcine smooth muscle cells (PSMCs). Treatment with 17betaE (10(-8) mol/L) abrogated p38 and p42/44 MAPK phosphorylation mediated by platelet-derived growth factor-BB as well as the migration and proliferation of PSMCs. In contrast, treatment with 17betaE (10(-8) mol/L) induced the phosphorylation of p38 and p42/44 MAPK and the migration and proliferation of PAECs. Interestingly, the effects of 17betaE on PSMCs and PAECs were reversed by selective estrogen receptor antagonists (tamoxifen, 4-OH-tamoxifen, and raloxifen). These results suggest that in PSMCs, 17betaE inhibits chemotactic and mitogenic effects of platelet-derived growth factor-BB as well as p38 and p42/44 MAPK phosphorylation. In contrast, 17betaE promotes in PAECs the phosphorylation of p42/44 and p38 MAPK as well as the migration and proliferation of these cells. Conclusions-Treatment with 17betaE has a dual beneficial effect: the improvement of vascular healing and the prevention of restenosis after angioplasty.