The preliminary characterization of a vasoactive circulating factor(s) in preeclampsia

OBJECTIVE: The endothelium-dependent behavior of myometrial resistance vess els from women with preeclampsia differs dramatically from that of healthy pregnant women. Similar functional changes may be induced in vessels from h ealthy pregnant women by incubation with plasma from women with preeclampsi a. STUDY DESIGN: Myometrial arterioles, obtained from healthy pregnant women a t elective cesarean section, were incubated with plasma from women with pre eclampsia or plasma from healthy pregnant women; Myographic techniques were used to study the endothelium-dependent relaxation to bradykinin. The effe cts of subjecting plasma from women with preeclampsia to heat treatment, ch arcoal stripping, protein extraction and digestion, and column fractionatio n on the inducible changes in endothelial function were likewise investigat ed. RESULTS: Incubation with plasma from women with preeclampsia resulted in a significant reduction in the vessel's endothelium-dependent relaxation, a c hange that was reversible. This effect was reduced by heat treating and cha rcoal stripping, maintained within a plasma protein concentrate, and comple tely removed by protease digestion. The vasoactive component(s) of the plas ma had a molecular weight greater than 100 kd. CONCLUSIONS: Plasma of women with preeclampsia alters the endothelium-depen dent relaxation of myometrial vessels. Our findings suggest that such alter ations are induced by a high-molecular-weight protein/ glycoprotein, with p ossible contributions from a hydrophobic, lipophilic factor.