WIP 68 - Hydrogen Sulfide Metabolites in Preterm Infants Born to Mothers with Preeclampsia at Risk for Developing Pulmonary Hypertension - A Pilot Study
Fellow Physician Loma Linda University Children's Hospital Pomona, California, United States
Background: The physiologic fetal-to-neonatal transition (FNT) includes an exponential decrease in pulmonary vascular resistance in response to increased oxygen tension in the first few days of life. Preterm infants exposed to placental insufficiency in utero are at increased risk of pulmonary hypertension (PH) due to altered response to tissue oxygen tension because of vascular dysgenesis. Hydrogen sulfide (H2S), an endogenous gasotransmitter that causes vasoconstriction of the pulmonary vasculature, is eliminated enzymatically in the presence of oxygen. Currently, little is known about the effects of the FNT on H2S metabolism or the role of H2S in regulating pulmonary vascular resistance after birth. Characterization of H2S metabolism in normal and at-risk infants during FNT may provide new targets for identifying and treating infants with PH. Objective: To characterize circulating H2S metabolite levels during the first week of life in preterm infants from mothers with or without hypertensive disorders of pregnancy. Design/Methods: This single-center, prospective, pilot study began enrollment in 2022 after obtaining institutional IRB approval for infants born at less than 33 weeks gestation. Mothers with multiple gestations, COVID-19 infection in labor, illicit drug use, or infants with congenital anomalies or metabolic disorders were excluded. The placenta and cord blood plasma at birth, along with neonatal plasma at 24 hours, 3, and 7 days were isolated, snap-frozen, and stored in -80°C. A novel assay method utilizing negative-ion chemical ionization gas chromatography mass spectroscopy is being used to quantify levels of various H2S metabolites. Enrollment, data collection, and analysis will be complete by February.
