Placental superoxide is increased in pre-eclampsia

One of the current hypotheses on the pathophysiology of pre-eclampsia (PE) states that the placenta secretes one ol more cytotoxic factors resulting i n maternal endothelial dysfunction. Among the candidate factors are the pro ducts of increased oxidative stress. Although there is circumstantial evide nce of such an increase, direct evidence is still lacking. Electron paramag netic spin trap resonance (EPR), the most direct method to detect free radi cals in tissues. was used to measure superoxide levels in placentae from no rmal pregnancies (n=13) and pregnancies complicated by PE (n=10). The super oxide level was significantly increased in the placental tissue of pre-ecla mptic women. Moreover, upon inhibition of Cu-Zn superoxide dismutase (SOD) activity the relative increase of the superoxide levels was significantly s maller in the placentae fi om the PE patients, implying decreased basal Cu- Zn SOD activity:. These findings lend direct support to the hypothesis that oxidative stress in placental tissue is increased in PE. (C) 2001 Harcourt Publishers Ltd.