Researchers say single RNA injection may help heart repair after heart attack

A new study shows a one-time RNA injection may help the heart repair damage after a heart attack by producing healing molecules, offering a less invasive approach to cardiac recovery

A new experimental RNA-based injection may help the heart repair itself after a heart attack by producing a heart-healing molecule, which could offer a less invasive way to treat heart damage, say scientists.

 

The study titled Single intramuscular injection of self-amplifying RNA of Nppa to treat myocardial infarction, published in the journal Science, finds that a single injection reduced scar tissue and improved heart function in a preclinical study across multiple mice models. 

What happens to the heart after a heart attack? 

A heart attack, or myocardial infarction, occurs when blood flow to part of the heart is blocked. While emergency treatments like stents can restore circulation, experts say the damage does not simply disappear, as heart muscle cells that die during a heart attack do not regenerate effectively. Instead, scar tissue forms, weakening the heart and increasing the risk of heart failure over time. This limited ability of the adult heart to heal has been one of cardiology’s biggest challenges. Interestingly, newborn mammals briefly have the ability to regrow heart tissue.

 

 

The study found that this regenerative ability is linked to a hormone called atrial natriuretic peptide (ANP). In newborn mice, the gene that produces ANP, called Nppa, increases more than 25 times after injury. In adults, however, this increase is much smaller and not enough to support proper repair.

 

When researchers blocked this gene in newborn mice, their ability to heal dropped significantly, highlighting its critical role. 

What is this new RNA-based therapy and how does it work? 

According to the study, instead of directly delivering a drug to the heart, scientists have turned the body into its own medicine factory.

 

The therapy uses self-amplifying RNA (saRNA) packaged in lipid nanoparticles. Once injected into skeletal muscle (such as in the arm), the RNA instructs muscle cells to produce an inactive form of a healing molecule called pro-ANP.

 

This molecule then travels through the bloodstream to the heart, where it is converted into active ANP. 

How does the injection target the heart without surgery? 

The researchers say the therapy relies on the body’s own biology for precision. An enzyme called Corin, which is found in much higher levels in the heart than elsewhere, activates the molecule only when it reaches cardiac tissue. This ensures that the healing effect is focused where it is needed most, without invasive delivery methods.

 

This means no open-heart procedures and no catheter-based delivery, just a simple intramuscular injection.

 

In preclinical experiments involving both small and large animals, the results show: 

• Reduced scar tissue in the heart 
• Improved heart function after injury 
• Benefits seen even when treatment was delayed by a week 
• Effectiveness across conditions like ageing, diabetes, and atherosclerosis 

The researchers also found that the self-amplifying RNA continued working for at least four weeks after a single injection, potentially reducing the need for frequent treatments. 

Could this RNA therapy replace current heart treatments? 

Not immediately, but it could transform how heart damage is managed in the future. While the treatments available as of now focus on restoring blood flow and preventing further damage, this therapy aims to actively repair the heart.

 

If proven effective in humans, it could complement or even reduce the need for more invasive interventions like transplants or cell therapies.

 

The therapy is still in the experimental stage. Researchers are now preparing for early-phase human trials to test safety and effectiveness.