Effects of a phosphodiesterase-5 (PDE5) inhibitor on endothelium-dependent relaxation of myometrial small arteries

In preeclampsia, endothelium-dependent function is markedly aberrant. Myometrial resistance arteries from women with preeclampsia show a minimal, wholly nitric oxide-mediated, bradykinin-induced relaxation. Our aim was to test that phosphodiesterase 5 (PDE5) inhibition could improve endothelium-dependent function in preeclampsia. Small arteries dissected from myometrial biopsies obtained at cesarean section from normal pregnant women (N = 22) or women with preeclampsia (N = 24) were mounted on wire or pressure myographs. Vessels were constricted (arginine vasopressin or U46619) and relaxed (bradykinin) before and after incubation with a PDE5 inhibitor, UK-343664. Endothelium-dependent vasodilatation was decreased in vessels from women with preeclampsia. 100 nmol/L UK-343664 did not affect normal pregnant but significantly improved relaxation of the vessels from women with preeclampsia. A PDE5 inhibitor enhances endothelial function of myometrial vessels from women with preeclampsia, such that the behavior of these arteries approximates to those from normal women. These agents offer a potential therapeutic strategy for the management of preeclampsia.