They found that the pathological condition of HF impairs the rejuvenation of cardiac-derived exosomal cargoes such as miRNAs, and that exosome-derived miR-21-5p contributes to exosome-mediated cardiac repair by enhancing cardiomyocyte survival via the PTEN/Akt pathway [129]. The gene discussed is AKT1; the disease is hydrops fetalis.