Potential biomarkers of preeclampsia: inverse correlation between hydrogen peroxide and nitric oxide early in maternal circulation and at term in placenta of women with preeclampsia.

Preeclampsia (PE) is a pregnancy-specific disease that has been associated with future cardiovascular disease for the mother and her child. The etiology of PE is unclear but oxidative stress seems to play a major role in endothelial dysfunction and permanent systemic vasoconstriction shown in PE. Hydrogen peroxide (H(2)O(2)), a terminal metabolite of the cellular oxidative stress cascade, is also revealed as a component of oxidative ischemia/reperfusion stress in placenta. We were the first to show an increase in the levels of H(2)O(2) in the serum of preeclamptic women at term. H(2)O(2) is already known to reduce the production of NO by increasing the metabolism of arginases. The objective of this study was to investigate a possible correlation between nitric oxide (NO), a potent vasodilator, and H(2)O(2) throughout pregnancy. Thus, we simultaneously assessed the levels of NO and H(2)O(2) in the serum of normal and preeclamptic women at 10-15 and 37-40 weeks of pregnancy, and in placentas at delivery. Our findings showed an inverse correlation between increased levels of H(2)O(2) and decreased levels of NO early in maternal circulation and at term in placenta. This relationship is confirmed by our in vitro experiments which demonstrate that H(2)O(2) inhibits NO synthesis of cytotrophoblasts. In conclusion, our findings highlight an inverse correlation between H(2)O(2) and NO early in maternal circulation and in placenta of women with preeclampsia, paving the way for further studies examining the potential use of NO and H(2)O(2) as biomarkers in the prediction of preeclampsia.