Plasma nitric oxide levels and the expression of P-selectin on platelets in preeclampsia

OBJECTIVE: The purpose of this study was to investigate the correlation of plasma nitric oxide levels with the expression of P-selectin on platelets in preeclampsia. STUDY DESIGN: Plasma levels of nitrite and nitrate (the stable nitric oxide metabolites) and the expression of P-selectin on platelets (a platelet activation marker) were measured in 25 normal pregnant women and 25 women with preeclampsia. The effects of the inhibition of nitric oxide synthesis on the expression of P-selectin also was measured in vitro. RESULTS: Plasma nitrate levels and the expression of P-selectin averaged 30.5 +/- 2.2 micromol/L and 8.9% +/- 1.1% (SEM), respectively, in preeclampsia, which was significantly higher than in normal pregnancy (P <.05). Nitric oxide synthesis inhibition in vitro significantly increased the expression of P-selectin in normal pregnancy by 284% (P <.05), which was significantly higher than in preeclampsia (156%, P <.05). CONCLUSION: The inhibitory effects of increased nitric oxide on the expression of P-selectin is attenuated in preeclampsia, which may contribute partly to the pathogenesis of preeclampsia.