Abstract 9810: Acute Exposure to Vaping E-Liquid Induces Multiple Cardiotoxic Effects on Fetal-Like Human Induced Pluripotent Stem Cell-Derived Cardiomyocytes and Epicardial Cells

Abstract

Introduction: Cardiomyocytes (CM) and epicardial (EPI) cells are key to orchestrating proper heart development. Vaping during pregnancy is rising, however, its implications on the prenatal heart are not fully understood. We exploited the immature phenotype of human induced pluripotent stem (iPS)-derived CM (iCM) and EPI (iEPI) cells to investigate the acute effect of e-cigarette liquid (e-liquid) on early cardiogenesis. Hypothesis: E-liquid exposure triggers dysfunction in fetal-like cardiac cells via distinct mechanisms. Methods: Human iCM and iEPI cultures were exposed to heated e-liquid for 20 minutes, twice daily, for 3 weeks; controls were performed in parallel. Video microscopy monitored morphological alterations and contractions. Immunostaining/flow cytometry of cell markers, Annexin V, EdU incorporation quantified protein expression, cell viability and proliferation, respectively. Mean fluorescence intensity measured reactive oxygen species (ROS). Wound healing assays assessed cell migration. Data reported as mean±SD (n=4/study). Results: Human iPSCs were differentiated into cTnT + iCM and Wt1 + iEPI cells with ≥83% purity. Addition of e-liquid progressively pruned the iCM syncytium, and slowed contractions in small regions from day 12. E-liquid treatment dysregulated HIF1α/p53 signaling in iCM relative to control. This enhanced apoptosis (49±5% vs. 21±6%) and disrupted G 1 /S cell cycle progression (5±1% vs. 15±3% in S-phase). Sustained elevation of ROS production by 35±7% led to ~20% decline in NKX2.5 + progenitors (p<0.05 for all). E-liquid treatment also impaired iEPI motility (77±5% vs. 30±7% of open wound area), and reduced the proportion of iEPI-derived PFGFRβ + pericytes and αSMA + smooth muscle cells by ≥31% (p<0.05 for all). This was attributed to N-cadherin repression and E-cadherin upregulation, which promoted defective epicardial epithelial-to-mesenchymal transition that affected vascular mural cell differentiation. Conclusions: Acute e-liquid exposure is detrimental to iCM and iEPI cell survival, behavior and fate trajectories. Our study suggests that long-term maternal vaping may compromise fetal cardiovascular integrity and maturation, heightening the risk of developing congenital heart disease.