Lipoperoxidation and antioxidant enzymes activity in pregnancy complicated with hypertension

Abstract

Objective: To assess maternal circulating levels of lipid peroxidation breakdown products and antioxidant enzymes activity in pregnancies complicated with hypertension. Study design: Ten women with uncomplicated pregnancies and nine women with hypertension antedating pregnancy were prospectively sampled. Eight women, who had developed preeclampsia, were also cross-sectionally included. Twenty healthy non pregnant volunteers were the control group. Thiobarbituric acid reactive substances (TBA-RS), as lipid peroxidation products, and the activity of catalase (CAT), glutathione peroxidase (GPX) and superoxide dismutase (SOD), as antioxidant enzymes, were assayed in red blood cell hemolysates. A prooxidant/antioxidant (P/A) ratio (TBA-RS/CAT + GPX + SOD) was determined from the mean value of the volunteers. Results: In women with chronic hypertension, TBA-RS levels were higher than those in normal pregnant women, whereas antioxidant enzymes activities were either stable or decreased. Therefore the P/A ratio was progressively lower in the second and third trimester. Similar results were found in patients with preeclampsia. Conclusions: Normal gestation induces an increase of lipid peroxidation products, whereas antioxidant activity seems stable. In pregnancies complicated by chronic hypertension, a deficiency of the oxidative system balance is detectable, which consistently progresses in the second and third trimester, strongly suggesting a failure of the protective mechanisms.