MECHANICAL-STRESS ELIMINATES THE EFFECTS OF PLASMA FROM PATIENTS WITHPREECLAMPSIA ON ENDOTHELIAL-CELLS

OBJECTIVE: Our purpose was to determine whether mechanical deformation alters in vitro effects of plasma from patients with preeclampsia on endothelial cell function to produce a paradigm similar to the in vivo disease state. STUDY DESIGN: The effects of 2% plasma from 12 patient s with preeclampsia and 12 normal pregnant women on prostacyclin, nitr ic oxide, and endothelin production by cultured endothelial cells were measured in the presence or absence of cyclic stretch and laminar she ar stress. RESULTS: In the absence of mechanical stress plasma from pa tients with preeclampsia resulted in greater prostacyclin and nitric o xide production (but no change in endothelin production) compared with plasma from normal pregnant women. Cyclic stretch did not affect pros tacyclin or endothelin production but produced similar increases in ni tric oxide production in cells exposed to plasma from the two groups. Shear stress markedly increased prostacyclin and nitric oxide producti on (but did not alter endothelin production). In the presence of shear stress there were no differences in production rates of nitric oxide or prostacyclin between cells exposed to plasma from the two groups. C ONCLUSION: Shear stress alters the effects of plasma on endothelial ce lls. This is an important caveat in the interpretation of previous sta tic in vitro culture studies and may partially explain the dichotomy b etween in vitro studies and in vivo findings in preeclampsia.