Preeclampsia is associated with altered Ca2+ regulation and nitric oxide production in human fetal venous endothelial cells

Preeclampsia (PE) is a leading cause of maternal hypertension in pregnancy, fetal growth restriction, premature birth, and fetal and maternal mortality (1). Activation and dysfunction of the maternal and fetal endothelium in PE may be the consequence of increased oxidative stress associated with circulating lipid peroxides (2-4), and in cases of severe maternal hypertension, uterine and umbilical artery waveforms are abnormal (5). We have investigated PE-associated abnormalities in the regulation of intracellular Ca2+ ([Ca2+](i)) and cyclic guanosine monophosphate (cGMP) production (index of nitric oxide [NO]) in human fetal umbilical vein endothelial cells. Basal [Ca2+](i) was slightly elevated in PE cells, whereas agonist-stimulated Ca2+ entry was reduced in cells from PE compared with normal term or age-matched preterm pregnancies. Furthermore, PE cells exhibited a decreased permeability to Ba2+ but an increased permeability to Mn2+ and Gd3+, suggesting that PE is associated with phenotypic alterations in fetal endothelial cation channel(s). Basal and histamine-stimulated cGMP levels were elevated in PE compared with preterm or normal cells, implying an increased NO production in PE. However, immunoblots for endothelial NO synthase (eNOS) and soluble guanylyl cyclase (sGC) revealed reduced eNOS expression in PE and preterm cells, with negligible changes in sGC levels. This study provides important and novel insights into abnormalities of fetal endothelial cells isolated from women with PE, revealing an altered cation membrane permeability and activity of eNOS-sGC pathway. As these changes are sustained in culture in vitro, this may reflect long-term "programming" of the fetal cardiovascular system.