A protein produced by the heart during its development could be used to repair heart attack damage, research suggests.
Protein stops cell death
University of Texas scientists worked on mice, but hope their findings will eventually lead to new treatment for heart disease.
The protein, Thymosin beta-4, is already used in clinical trials to promote wound healing on the skin.
The Nature research found it prevented cell death and limited scar tissue formation after a heart attack.
Thymosin beta-4, is produced by embryos during the heart's development. It plays a key role in keeping heart cells alive, and ensuring they migrate to the right place.
The Texas team simulated a heart attack in 58 adult mice by tying off the coronary artery.
Half of the animals were given injections of Thymosin beta-4, and the rest a control injection of saline.
The researchers found that Thymosin beta-4 caused fewer cells in the affected part of the heart to die, resulting in improved function even several weeks after the heart attack.
They believe the protein triggers changes in cell metabolism to create stronger heart muscle cells that can resist the low oxygen conditions after a heart attack.
Lead researcher Professor Deepak Srivastava said it was hoped to launch clinical trials using the protein to treat the heart in the near future.
The next step will be to determine the most effective dose, the best time to administer it, and how long it after a heart attack it can be given and still remain effective.
Stem cell therapy
Professor Jeremy Pearson, associate medical director of the British Heart Foundation, said current trials were investigating whether stem cell therapy - direct injection of cells from the patient's own bone marrow into cardiac tissue - can help the heart to heal after a heart attack.
"However, the procedure is not yet proven to be very effective, and the way these cells might aid repair is poorly understood," he said.
"Recently it has been discovered that the heart itself contains stem cells, which, if they could be encouraged to form adult heart cells following a heart attack, would provide an alternative and potentially better way to help healing.
"The research in this paper provides a substantial step towards this goal, by identifying a natural protein that has exactly this effect when used in mice.
"Since the protein is already licensed for clinical use (to promote wound healing) it is likely that trials for its use in patients after a heart attack could start quickly."