Maternal Angiotensinogen Genotype and Fetal Sex Impact Uteroplacental Function and the Developmental Origins of Stress-Induced Hypertension

Fetal growth restriction (FGR) is a common and potentially life-threatening complication that affects 5-10% of human pregnancies. Maternal genetic predisposition and fetal male sex are known risk factors, but the underlying mechanisms are unknown. To study a known maternal genetic risk factor and the impact of fetal sex, we employed a published transgenic (TG) mouse model, which was designed to mimic a common human angiotensinogen (AGT) promoter variant associated with a 20% increase in circulating AGT levels. We hypothesized that TG dams would deliver growth restricted pups and that the underlying mechanism would be related to differences in maternal uterine pregnancy-induced vascular remodeling, abnormal blood flow to the placenta, and placental damage. In addition, since growth restricted human males are at an increased risk of developing adult onset hypertension, which has been associated with reduced nephron development, we tested for developmental programming in our mouse model and the impact of fetal sex. Our results show that TG dams have reduced uterine and placental angiogenesis when their pups were males, but relatively normal angiogenesis in the female siblings compared with wild-type controls. The uterine placental bed in TG dams had abnormal pro-angiogenic/anti-angiogenic expression ratios that were related to differences in uterine natural killer cell activation and fetal sex. The abnormal phenotype could be rescued by delivering vascular endothelial growth factor (VEGF) to uterine endothelial cells. Male progeny from TG dams had abnormal kidney epigenetic changes, fewer nephrons as adults, and they developed stress-induced hypertension. We conclude that the combination of maternal genetic risk and fetal male sex affect uteroplacental angiogenesis leading to FGR and the programming of stress-induced hypertension