Elongating human heart organoids recapitulate early cardiac morphogenesis and axial organization.

Elongating human heart organoids (EHOs) mimic early cardiac morphogenesis, including elongation, looping, and axial organization, with a 50% reduction in length upon TBX5 deletion.

• Why it matters: Understanding early heart development is crucial for insights into congenital heart defects, yet these processes are difficult to study in vivo. Existing models lack the ability to replicate early morphogenetic events.
• What they did: Researchers generated EHOs from human induced pluripotent stem cells that undergo coordinated elongation and curvature, establishing a venous-to-arterial axis with organized cardiomyocyte subtypes, supported by single-cell transcriptomics and pulse-labeling.
• The result: EHOs enable detailed investigation of early cardiac morphogenesis, revealing that cardiac elongation is driven by splanchnic mesodermal cell incorporation, and demonstrating that TBX5 deletion impairs elongation and looping, advancing in vitro modeling of heart development.