Overview
- A peer‑reviewed study published on November 9, 2026 in Nature Cardiovascular Research showed that a transiently delivered modified mRNA can make adult mouse cardiomyocytes divide and repair tissue after a heart attack.
- The treatment works by briefly expressing two proteins, Myc and Cyclin T1, inside heart muscle cells to trigger cell division rather than permanently altering the genome.
- In the mouse experiments the therapy was injected directly into the heart and produced about a 10% increase in the amount of blood pumped per beat versus mock treatment with improvements still measurable at 28 days and at 12 weeks.
- No adverse effects were reported in the treated mice, and the team has received funding from the British Heart Foundation to refine the approach and carry out larger‑animal preclinical studies before any human trials.
- Because adult human hearts normally cannot replace lost cardiomyocytes and a heart attack can destroy up to roughly a billion such cells, researchers say this is an important early proof of concept but caution that success in mice does not guarantee safety or benefit in people.