Placental production of lipid peroxides, thromboxane, and prostacyclin in preeclampsia

Objective: The pathophysiology of preeclampsia includes an imbalance of increased thromboxane and decreased prostacyclin. Recently attention has been given to lipid peroxides because their levels are abnormally increased in the maternal circulation of women with preeclampsia. Since preeclampsia occurs in the presence of the placenta or placental tissue, we examined the hypothesis that the production of lipid peroxides is significantly higher in placentas obtained from women with preeclampsia than from women with normal pregnancies. Methods: Placentas were obtained from 6 normally pregnant women and 6 women with preeclampsia. Placental tissues (350 mg) were incubated in DMEM for 48 h. Samples were collected at 0, 2, 6, 16, 28, and 48 h of incubation. Main Outcome Measures: Samples were analyzed spectrophotometrically for lipid peroxides by a peroxide equivalent assay, and for thromboxane and prostacyclin by radioimmunoassays of their stable metabolites, thromboxane B-2 and 6-keto PCF1 alpha. Results: As compared to placentas obtained from normally pregnant women, placentas obtained from women with preeclampsia produced significantly more lipid peroxides (91 +/- 11 vs. 191 +/- 33 pmol/mu g after 48 h of incubation) and more thromboxane (22.3 +/- 4.0 vs. 34.9 +/- 4.6 pg/mu g at 48 h) but less prostacyclin (15.5 +/- 2.6 vs. 9.4 +/- 1.4 pg/mu g at 48 h, respectively). The increases in lipid peroxide and thromboxane concentrations in the incubation medium were highly correlated (r = 0.769). Conclusions: Preeclamptic placentas produce significantly more lipid peroxides and thromboxane but less prostacyclin than normal. Since the placenta secretes lipid peroxides, it could be a source of increased lipid peroxides in the circulation of women with preeclampsia.