Immunomodulatory effects of MSC-EVs on heart transplant survival. (A) Schematic diagram of the study design and animal grouping. (B) Graphical representation of heart transplant survival rates under different treatments showing extended survival with MSC-EV^MLR treatment and the effect of miR-638 knockdown. n = 8 for each group. (C) Representative images of H&E staining of heart transplant in each group. n = 3 for each group.