Plasma from preeclamptic women increases human endotheial cell prostacyclin production without changes in cellular enzyme activity or mass,

OBJECTIVE: We investigated differencesin prostacyclin production by endothelial cells exposed to plasma from either preeclamptic women or normal pregnant women. STUDY DESIGN: A case-control study of matched preeclamptic and normal pregnancies was used to compare prostacyclin synthesis by human umbilical vein endothelial cells incubated with pregnancy plasma for 24 hours. Prostacyclin concentrations in conditioned media were measured by radioimmunoassay of its stable metabolite (6-keto-prostaglandin F1α). Human umbilical vein endothelial cell lysates 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 preeclamptic women was significantly greater than that by cells exposed to normal pregnancy plasma. Differences in prostacyclin production under the two experimental conditions could be explained neither by differences in enzyme mass nor activities of cyclooxygenase and prostacycline synthase. CONCLUSION: The stimulatory effect of preeclampsia plasma on prostacycline biosynthesis in human umbilical vein endothelial cells appears to be manifested at a step(s) proximal to the activation of cyclooxygenase. Possible mechanisms are increased phospholipase A2, lipoprotein, or lipid peroxide activities in preeclampsia