PLASMA FROM PREECLAMPTIC WOMEN INCREASES HUMAN ENDOTHELIAL-CELL PROSTACYCLIN PRODUCTION WITHOUT CHANGES IN CELLULAR ENZYME-ACTIVITY OR MASS

OBJECTIVE: We investigated differences in prostacyclin production by e ndothelial cells exposed to plasma from either preeclamptic women or n ormal pregnant women. STUDY DESIGN: A case-control study of matched pr eeclamptic and normal pregnancies was used to compare prostacyclin syn thesis by human umbilical vein endothelial cells incubated with pregna ncy plasma for 24 hours. Prostacyclin concentrations in conditioned me dia were measured by radioimmunoassay of its stable metabolite (6-keto -prostaglandin F-1 alpha). Human umbilical Vein endothelial cell lysat es were used to determine concentrations of the enzymes cyclooxygenase and prostacyclin synthase. RESULTS: Prostacyclin production by human umbilical Vein endothelial cells incubated with plasma from preeclampt ic women was significantly greater than that by cells exposed to norma l pregnancy plasma. Differences In prostacyclin production under the t wo experimental conditions could be explained neither by differences i n enzyme mass nor activities of cyclooxygenase and prostacyclin syntha se. CONCLUSION: The stimulatory effect of preeclampsia plasma on prost acyclin biosynthesis in human umbilical vein endothelial cells appears to be manifested at a step(s) proximal to the activation of cyclooxyg enase. Possible mechanisms are increased phospholipase A(2), lipoprote in, or lipid peroxide activities in preeclampsia.