Cardiovascular Organoids With Adjustable Endothelial Composition via SOX17‐Engineered hPSCs

ABSTRACT Organoids are considered a novel modeling platform for studying human biology and advancing health research. With the ability to demonstrate complex 3D structure and multicellular interactions, organoids have advanced studies in all major organs as a reliable model. In this study, we generated an advanced cardiovascular organoid by using a genome‐edited human pluripotent stem cell line with inducible SOX17 expression, enabling controlled endothelial specification, adjustable cell‐type composition, and human heart‐like morphology. Our organoids recapitulated the cardiotoxic phenotypes of FDA‐approved chemotherapeutic doxorubicin, manifesting as decreased cell viability and diminished contractile activity. Cryoinjury‐induced myocardial infarction in our organoids led to reduced beating, viability, and α‐actinin expression, along with increased fibroblast formation, which were mitigated by Captopril. Lastly, isoproterenol treatment increased peak Ca 2+ transient amplitude and shortened APD 50 in our organoids, consistent with previously reported β‐adrenergic responses. In summary, we established a protocol for generating in vitro 3D cardiovascular organoids with controllable cellular composition and heart‐like structures, providing a robust and easy‐to‐produce platform for future studies of human heart disease.