Abnormal levels of antioxidant defenses in a large sample of patients with hypertensive disorders of pregnancy.

Increased levels of oxidative stress have been demonstrated in Preeclampsia in previous studies, but this finding has not been established in other hypertensive disorders in pregnancy (HDP). We measured different markers of lipid peroxidation and antioxidant defenses by spectrophotometry or enzymoimmunoanalysis in 339 pregnant women: 85 with gestational hypertension (GH), 88 chronic hypertension (CH), 104 Preeclampsia and 62 healthy pregnant control women (PCW). Lower activity of superoxide dismutase and higher levels of catalase were found in GH, CH and preeclampsia compared with PCW (964.4±116.5, 970.0±120.4, 971.2±137.5 and 1063.4±133.7 U g(-1) Hb, P<0.001; and 313.0±71.7, 292.2±45.3, 297.1±47.2, 215.5±26.2 U mg(-1) Hb, P<0.0001; respectively). Regarding the glutathione REDOX cycle, we found the following in GH, CH and preeclampsia compared with PCW: a decrease in its reduced form (2.6±0.6, 2.7±0.8, 2.7±0.9, 3.3±1.3 μmol l(-1), P<0.003), a parallel increase in the oxidized form (185.6±68.9, 194.7±75.0, 184.3±78.3, 85.1±27.5 μmol l(-1), P<0.0001) and an increment in glutathione peroxidase (85.9±22.0, 86.4±20.9, 82.1±23.5 and 77.2±19.7 U g(-1) Hb, P<0.04) and glutathione reductase (6384.3±1261.9, 6724.6±1154.1, 6287.9±1399.9 and 6044.4±1208.4 mU g(-1) Hb, P<0.01, respectively). Nitrites/nitrates were higher in patients with preeclampsia than in PCW (31.50±15.08, 26.80±8.39 μmol l(-1), P<0.002). Although malondialdehyde and oxidized-LDL levels were similar among groups, free fatty acids were increased in every HDP (GH 514.6±194.6, CH 501.3±197.4, preeclampsia 555.2±230.1 μmol l(-1)) compared with PCW (351.4±146.1 μmol l(-1)), P<0.0001. Our results show an oxidation/reduction imbalance with an increase in oxidative stress coupled with a decreased capacity of antioxidant systems, not only in preeclampsia but also in every HDP.