The overall goal of this multiple PI application is to understand the basic cellular and molecular mechanisms underlying maternal, fetal and newborn vascular adaptation in response to high altitude, long-term hypoxia during gestation. Hypoxia is one of the most common and severe stresses to an organism's homeostatic mechanisms, and hypoxia during gestation has profound adverse effects on maternal health and developmental plasticity. Gestational hypoxia is associated with high incidence of clinical complications including preeclampsia and fetal intrauterine growth restriction (IUGR). Both human and animal studies have revealed a causative role of increased uterine vascular resistance and lowered uterine blood flow in preeclampsia and IUGR. Our recent studies revealed that high altitude hypoxia suppressed pregnancy-induced uterine arterial adaptation and increased uterine vascular resistance and systemic blood pressure in pregnant sheep. Infants born at high altitude show significantly increased risk of persistent pulmonary hypertension. We demonstrated that gestational hypoxia at high altitude elevated pulmonary vascular resistance and increased pulmonary artery pressure and pressure response to acute hypoxia in newborn lambs. In addition, fetal hypoxia negatively impacts cerebral vascular development and increases the risk of intraventricular hemorrhage in newborns. Hypoxic-mediated responses are highly integrated across many cell types; nonetheless, they are tissue specific. In many respects these responses differ significantly between the fetus and newborn, as well as between non-pregnant and pregnant states. Much remains unknown of the molecular mechanisms underlying programming of maternal, fetal and newborn vascular response to long-term hypoxia in gestation. The proposed study is broadly based, multidisciplinary, integrated project using physiological, pharmacological, cellular, biochemical, and molecular approaches to investigate the mechanisms underlying maternal uterine, and fetal and newborn pulmonary and cerebral vascular response to long-term hypoxia in gestation. Based on >25 years of research by our group, the proposed study will be conducted in sheep acclimatized to high altitude (3801 m/12,470 ft). The overall hypothesis is that high altitude, long-term hypoxia during gestation increases micro RNA-210 and endoplasmic reticulum (ER) stress, differentially regulating spontaneous transient outward currents (STOCs) in programming of maternal, fetal and newborn vascular response, impacting developmental plasticity and the subsequent risk for disease. The proposed study has strong scientific premise with a novel concept and an innovative and mechanistic approach. It will provide new insights into the understanding of fundamental mechanisms underlying programming of maternal, fetal and newborn vascular dysfunction caused by gestational hypoxia, impacting maternal health and developmental plasticity. Given that STOCs are fundamentally important in regulating vascular tone and blood flow in virtually all vascular beds, revealing molecular and epigenetic regulation of STOCs function in programming of vascular response to hypoxia will have broad impact in the comprehensive understanding of the mechanisms in vascular physiology and pathophysiology.
Chronic hypoxia during gestation has profound adverse effects on maternal health and fetal developmental plasticity. Yet, much remains unknown of molecular mechanisms in the response to long-term hypoxia in both the mother and her fetus. Scientifically, the studies will augment our understanding of basic mechanisms whereby the mother and fetus acclimatize to chronic hypoxia. From a clinical standpoint, these studies may provide new insights and suggest new directions in the clinical management of pregnancy complications and abnormal fetal development associated with gestational hypoxia, thereby reducing perinatal morbidity and mortality while improving maternal health and neonatal outcome.
