<b>Reprogramming of Human Urine Cells into Cardiomyocytes via a Small Molecule Cocktail in Xeno-Free Conditions</b>

<b>Background</b><br>Cell therapy, particularly using cardiomyocytes, shows significant promise for treating heart failure. Direct reprogramming of somatic cells into cardiomyocytes using small molecules is advantageous due to its efficiency and cost-effectiveness.<b>Methods</b><br>This study demonstrated transdifferentiation of human urine-derived cells (hUCs) into functional cardiomyocyte-like cells (hCiCMs) using a cocktail of 15 small molecules under xeno-free conditions. Various Characterizations were performed, including immunofluorescence, transmission electron microscopy (TEM), qPCR, single-cell RNA sequencing, patch-clamp recordings, and intracellular Ca²⁺ measurements. The therapeutic potential was tested in both mouse and porcine models of myocardial infarction (MI).<b>Results</b><br>Reprogramming efficiency achieved 15.08% on day 30, with 96.67% purity on day 60. hCiCMs displayed cardiomyocyte markers, sarcomeric structures, and abundant mitochondria. Electrophysiological analysis confirmed ventricular-like action potentials and regular calcium transients. Single-cell RNA sequencing revealed cardiomyocyte subpopulations resembling 13-week embryonic human heart cells, with gene ontology analysis indicating successful maturation. In the MI model, hCiCM transplantation improved cardiac function, increasing ejection fraction and fractional shortening while reducing fibrosis.<b>Conclusions</b><br>This study demonstrates the successful reprogramming of hUCs into functional hCiCMs using small molecules under xeno-free conditions, offering a scalable, autologous cell source for cardiac repair with significant potential for regenerative therapies.