Small artery endothelial dysfunction in postmenopausal women: in vitro function, morphology, and modification by estrogen and selective estrogen receptor modulators.

Objective: Our objective was to assess vascular endothelial function and morphology in resistance vasculature from healthy pre- and postmenopausal women in vitro and to determine potential mechanisms of vascular protection by estrogenic compounds.

Methods: Arteries (approximately 220 microm) were dissected from sc fat biopsies obtained from healthy premenopausal and postmenopausal women. Flow-mediated dilatation, agonist-induced endothelium-dependent and -independent relaxation, and myogenic responses to changes in intraluminal pressure were evaluated before and after incubation (3 h) with 17beta-estradiol, propyl pyrazole triol [a selective estrogen receptor-alpha (ERalpha) agonist], raloxifene (a second-generation selective ER modulator), and the phytoestrogen genistein, using pressure myography technique.