Ethanol exposure during differentiation of human induced pluripotent stem cells reduces cardiomyocyte generation and alters metabolism.

Prenatal alcohol exposure increases the risk of congenital heart diseases (CHDs) by disrupting fetal development, yet the mechanisms underlying alcohol-induced cellular and molecular changes in human cardiogenesis remain unclear. This study investigates the effects of ethanol exposure on cardiomyocyte differentiation using human induced pluripotent stem cells (hiPSCs) as a model. Cardiomyocyte differentiation was induced using Wnt signaling molecules, and hiPSCs were treated with ethanol at concentrations of 17, 50, and 100 mM from day 0 to day 12. Ethanol treatment impaired cardiac differentiation efficiency in the early stage (days 5-7) and reduced cell proliferation in the late stage (days 12-13) in a dose-dependent manner, resulting in fewer cardiac progenitors and cardiomyocytes. Additionally, ethanol exposure caused mitochondrial defects, characterized by redox imbalance, reduced membrane potential, and decreased mitochondrial content and cellular respiration. Proteomic analysis revealed downregulation of proteins involved in calcium binding and fatty acid oxidation, a key metabolic pathway for cardiac development. These findings shed light on the mechanisms by which alcohol disrupts cardiomyocyte differentiation and may inform strategies to mitigate alcohol-induced CHD risk.