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 (∼220 μm) 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 17β-estradiol, propyl pyrazole triol [a selective estrogen receptor-α (ERα) agonist], raloxifene (a second-generation selective ER modulator), and the phytoestrogen genistein, using pressure myography technique. In addition, endothelial morphology was assessed in arteries from pre- and postmenopausal women, and distribution of ERs within the artery wall from postmenopausal women was evaluated. Results: Functional and morphological distu...