Researchers at the Weizmann Institute of Science in Israel have uncovered a molecule found in newborns that aids in regenerating damaged hearts, and are now testing ways that the molecule could treat victims after MI.

The study, published June 6 in Nature, examined how the molecule, called Agrin, works to enable heart muscle repair. Eldad Tzahor, an associate professor at the Weizmann Institute, led the study in conjunction with PhD students.

A human heart is unable to regenerate itself after it’s been damaged. Cardiomyocytes are replaced by scar tissue, which is incapable of contracting and pumping, leading to eventual heart failure. But work in the current study could help provide a treatment that would naturally regenerate that damaged tissue.

The researchers tested their theory on mice. When Agrin was injected into the hearts of adult mice that suffered a heart attack, it triggered a renewal process that repair damaged heart muscle. Only a single injection allowed their hearts to completely heal and become fully functional, but it took about a month. And after a recovery period, scar tissue was dramatically reduced and replaced with living heart tissue.

"Clearly this molecule sets a chain of events in motion" Tzahor said in a statement. "We discovered that it attaches to a previously unstudied receptor on the heart muscle cells, and this binding takes the cells back to a slightly less mature state—closer to that of the embryo—and releases signals that may, among other things, initiate cell division."