Abstract Background Studying human cardiac development and regeneration requires models that recapitulate the heart’s native multicellular environment. However, conventional in vitro systems are often too simplistic, failing to capture the cellular diversity and tissue-level interactions of the human heart. To bridge this gap, we developed and characterized a multicellular Bioengineered Heart Muscle (BHM) platform derived from human induced pluripotent stem cells (hiPSCs) to model cardiac development, maturation, and stress response mechanisms. Methods BHMs were generated via a stage-specific directed differentiation protocol mimicking in vivo development through mesoderm induction (3 days), cardiac specification (10 days), and extended maturation (up to 60 days). To investigate mechanobiological influences, constructs were cast onto flexible poles of defined stiffness within a 48-well format. Contractile function was monitored longitudinally using a high-throughput video-optical imaging platform to quantify fractional shortening, beating frequency, and contraction dynamics. Results BHMs exhibited progressive functional maturation with increasing contractile force over 60 days and maintained robust beating across stiffness conditions. RNA-seq analysis revealed a developmental trajectory mirroring human heart maturation, with early expression of mesodermal markers (ISL1, HAND1) and later upregulation of key structural and metabolic genes (MYH7/MYH6, TNNI3/TNNI1), indicative of a metabolic shift toward fatty acid oxidation. Immunohistochemistry confirmed the presence of cardiomyocytes, fibroblasts, endothelial cells, and WT1-positive epicardial-like cells, reflecting native cardiac complexity. Under hypoxia–reoxygenation, BHMs exhibited a significant decline and partial recovery in contractile performance upon reoxygenation, effectively modeling an ischemic stress response. Conclusion This hiPSC-derived BHM platform successfully recapitulates key structural and functional hallmarks of human cardiac development, including multicellular organization and mechanobiological adaptation. This platform represents a robust, high-throughput system for investigating cardiac mechanobiology, modeling heart diseases, and evaluating novel cardioprotective or regenerative therapies with broad translational potential.
Nedunchezhian et al. (Fri,) studied this question.