Heart regeneration faces two connected challenges: replacing lost muscle and keeping transplanted cells safe and accepted by the body. Charles Murry, M.D., Ph.D., of USC explains why the adult heart heals major cardiomyocyte loss with scar tissue rather than new muscle, leading to progressive heart failure. Murry describes how stem cell derived cardiomyocytes can be manufactured at scale, transplanted into injured hearts, and tested for function in animal models. He also examines major barriers, including graft related arrhythmias, calcium handling stress, immune rejection, and the need for practical immunosuppression or immune edited cells. By connecting cell manufacturing, electrophysiology, immunology, and clinical trial planning, this research shows why heart regeneration is difficult and why careful translation matters for patients with severe heart injury. Series: "Stem Cell Channel" [Health and Medicine] [Science] [Show ID: 40853]