ABSTRACT
OBJECTIVE: Our purpose was to compare the expression of endothelial nitric oxide synthase in the placenta and umbilical cord of preeclamptic placenta with that of the normotensive placenta. METHOD: We compared placental endothelial nitric oxide synthase expression in preeclamptic (n=5) with in normal (n=5) pregnancies. Frozen sections of umbilical cords, chorionic plate vessels, and terminal villi were immunostained with a monoclonal endothelial nitric oxide synthase antibody. RESULTS: The age revaled no difference between control (28.1+4.2 years). and study group (26.1+4.7 years). The gestational age was statistically different between control (38.9+1.7 weeks) and study group (34.9+3.5 weeks). The neonatal body weight and placental weight were also statistically different between control (3060+528 g) and study group (2160 417 g). No difference in endothelial nitric oxide synthase immunostaining in the endothelium of the umbilical vessels and stem villous vessels was found between preeclamptic and normotensive pregnancies. In contrast, in the preeclamptic placental endothelial nitric oxide synthase immunostaining was seen in the terminal villous vessels. In the syncytiotrophoblast endothelial niric oxide synthase immunostaining appeared primary basal in location and diffuse in distribution in the preeclamptic placentas but primary apical in the normotensive placentas. CONCLUSION: Differences in endothelial nitric oxide synthase expression in terminal villous vessels and syncytiotrophblast may be a result of vascular alterations or damage that take place in the placenta in preeclampsia.