“…Infusions and injections of cell solutions containing mesenchymal stem cells (MSCs), iPSCs, and iPSC-derived CMs (iPSC-CMs) have shown modest recovery in some in vivo models [3,8,12] but highly variable results in human clinical trials for CVD, as poor cell retention and host integration challenge long-term treatment efficacy [1,3,8,10,12,27]. Over 99% of transplanted cells in solution quickly die for various reasons: host immune reactions, inflammation, protease release, low cell density, deficient cell-cell interactions needed to promote cell survival, and poor cell-type diversity, which limits host integration [1,10,27,30,34,35]. Critically, transplanting immature tissue poses an arrhythmia risk from improper CM electrical integration [10,24,27,30,31,34].…”