Nifedipine Prevents Apoptosis of Alcohol-Exposed First-Trimester Trophoblast Cells

BackgroundMaternal alcohol abuse leading to fetal alcohol spectrum disorder (FASD) includes fetal growth restriction (FGR). Ethanol (EtOH) induces apoptosis of human placental trophoblast cells, possibly disrupting placentation and contributing to FGR in FASD. EtOH facilitates apoptosis in several embryonic tissues, including human trophoblasts, by raising intracellular Ca2+. We previously found that acute EtOH exposure increases trophoblast apoptosis due to signaling from both intracellular and extracellular Ca2+. Therefore, nifedipine, a Ca2+ channel blocker that is commonly administered to treat preeclampsia and preterm labor, was evaluated for cytoprotective properties in trophoblast cells exposed to alcohol. MethodsHuman first-trimester chorionic villous explants and the human trophoblast cell line HTR-8/SVneo (HTR) were pretreated with 12.5 to 50nM of the Ca2+ channel blocker nifedipine for 1hour before exposure to 50mM EtOH for an additional hour. Intracellular Ca2+ concentrations were monitored in real time by epifluorescence microscopy, using fluo-4-AM. Apoptosis was assessed by terminal deoxynucleotidyl transferase dUTP nick end labeling (TUNEL), accumulation of cytoplasmic cytochrome c, and cleavage rates of caspase 3 and caspase 9. ResultsThe increase in intracellular Ca2+ upon exposure to EtOH in both villous explants and HTR cells was completely blocked (p<0.05) when pretreated with nifedipine, accompanied by inhibition of EtOH-induced release of cytochrome c, caspase activities, and TUNEL. ConclusionsThis study indicates that nifedipine can interrupt the apoptotic pathway downstream of EtOH exposure and could provide a novel strategy for future interventions in women with fetuses at risk for FASD.