Modeling embryonic heart vascular plexus development and sympathetic innervation on a human heart organoid

Coronary vascularization and sympathetic innervation are tightly coordinated during heart development and are essential for normal cardiac function. Here, we present a self-organized human iPSC-derived epicardium-myocardium organoid (EMO) that mimics heart vascular plexus development and integration with myocardium sympathetic innervation. Through the modulation of VEGF and PDGFβ signaling, EMOs develop a functional, self-generated coronary-like vascular plexus (V-EMOs). and display active epicardial-to-mesenchymal transition trajectories into fibroblast, mural, and vascular cell lineages, mirroring <i>in vivo</i> processes. Assembly of these vascularized EMOs with human iPSC-derived sympathetic neuron spheroids yields innervated EMOs exhibiting integrated neurovascular organization and functional responses to nicotine stimulation (iV-EMOs). This modular, developmentally guided organoid system features coordinated human cardiac, vascular, and neural development, providing a physiologically relevant platform for studying heart morphogenesis, neurovascular interactions, and regenerative therapeutic strategies.