Plasma nitric oxide, endothelin-1, arginase and superoxide dismutase in pre-eclamptic women

Aim: The aim of this study was to determine several parameters of nitric oxide metabolism in pre-eclamptic patients. Methods: We conducted a nested case-control study at the Department of Obstetrics and Gynecology, Sao Jose Hospital, Brazil. Thirty-five pre-eclamptic and 35 normotensive pregnant women were included in the study. Pre-eclampsia was diagnosed as an increase in diastolic blood pressure (BP) of 15 mm Hg and systolic BP of 30 mm Hg at two measurements at least 4 h apart, compared with BP obtained before 20 weeks of gestation, and proteinuria > 0.3 g/24 h in the absence of urinary tract infection. Fasting peripheral venous blood samples were obtained during the antepartum period in pre-eclamptic and control (matched for maternal age and gestational age) patients. Results: Plasma nitrite was significantly lower and plasma endothelin levels were significantly higher in pre-eclamptic women than in normotensive pregnant women. Superoxide dismutase activity was decreased and arginase activity was significantly increased in pre-eclamptic patients when compared to normotensive pregnant women. Conclusions: We suggested that in pre-eclampsia excessive arginase and low superoxide dismutase activity leads to a decrease nitric oxide levels and oxidative stress, and this may promote microvascular oxidative damage and endothelial dysfunction.