Scientists have demonstrated that a short‑acting mRNA therapy can reactivate dormant heart muscle cells, causing them to divide and improve cardiac performance in mice that have suffered a heart attack. The treated animals showed roughly a 10% rise in the volume of blood pumped with each heartbeat compared with a control group that received a mock injection.
How the therapy works
The approach delivers messenger RNA that temporarily produces two proteins—Myc and Cyclin T1—inside cardiomyocytes. Both proteins are known to drive cell‑cycle entry, and their brief activation is intended to stimulate repair without creating permanent genetic changes. Because the mRNA degrades quickly and the delivery is localized to the heart, the risk of uncontrolled cell growth is minimized, and no adverse effects were observed in the mouse experiments.
Study results in mice
In the pre‑clinical trial, mice underwent induced myocardial injury to mimic a heart attack. Researchers injected the modified mRNA directly into the heart tissue and monitored function using echocardiography, an imaging technique comparable to prenatal ultrasound. Compared with the mock‑treated cohort, the mRNA‑treated mice displayed a stronger heartbeat and an increased stroke volume of about 10%.
Follow‑up assessments at 28 days and again at 12 weeks after treatment indicated that the functional gains persisted over the longer term. The study authors note that the therapy’s transient nature means it does not permanently alter the genetic makeup of the cells, a design choice aimed at reducing the potential for overgrowth or tumor formation.
Implications and next steps
Dr. Catherine Wilson, associate professor at the University of Cambridge’s Department of Pharmacology and Gurdon Institute and co‑senior author of the paper, emphasized that the work moves beyond merely alleviating symptoms of heart failure. “We’re not just treating the symptoms of heart failure – this approach could help the heart to repair itself,” she said.
Professor Bryan Williams, chief scientific and medical officer at the British Heart Foundation, described the findings as a step toward the “holy grail” of cardiology: enabling the adult heart to regenerate. He highlighted that while adult human hearts lose up to one billion muscle cells after a myocardial infarction and lack natural regenerative capacity, re‑awakening these cells could transform treatment pathways.
The research team has secured additional funding from the British Heart Foundation to refine the therapy and to test it in larger animal models. Subsequent phases will focus on safety profiling and dosage optimization before any human clinical trials can commence. If the approach proves effective in humans, it could complement existing heart‑failure therapies, which currently manage symptoms and slow disease progression but cannot replace lost cardiac muscle.
Heart failure remains a major health burden, with approximately 200,000 new diagnoses each year in the United Kingdom alone. Even modest improvements in cardiac function have been linked to lower mortality and better daily functioning for patients. As populations age and the prevalence of heart disease rises, the potential to restore lost heart muscle could have far‑reaching economic and quality‑of‑life implications.
The study, titled “A transient modified mRNA encoding Myc and cyclin T1 improves cardiac function after myocardial injury,” was published today in Nature Cardiovascular Research. While the results are limited to mouse models, the authors regard the work as a promising proof of concept that could pave the way for regenerative treatments for millions of heart‑failure patients worldwide.
Helene Elliott is the Lead Science & Space Reporter at News Raise. She reports on aerospace missions, astrophysics discoveries, quantum research, and environmental technology.
