Heat Shock Protein 27: Clue to Understanding Estrogen-Mediated Atheroprotection?

Although the use of estrogen replacement therapy for postmenopausal women has been dramatically curtailed due to an unfavorable risk-benefit profile, there remains strong experimental evidence that ovarian hormones have a favorable effect on vessel wall homeostasis. We recently discovered that release of heat shock protein 27 (HSP27) into the serum is atheroprotective and mediated by ovarian hormones, preferentially functioning via estrogen receptor-β. HSP27 binds scavenger receptor-A, reduces cholesterol uptake in macrophages, and attenuates mediators of vascular inflammation. Therefore, it is attractive to consider HSP27 as the active foot soldier of estrogens and potentially a novel therapeutic opportunity for vascular disease.