A team at Boston Children's Hospital tested the technique in rats, placing the cell growth-stimulating protein periostin on a Gelfoam patch over tissue damaged by heart attacks induced in the left ventricles.

Twelve weeks later the patch was still releasing periostin, and the rats had less scarring, a smaller injury site and more blood vessels feeding the area, which resulted in better ejection fractions and improved ventricular remodeling.

The animals also had 100 times more dividing heart muscle cells than they did after the heart attack and had grown 6 million new cells, which exceeded the number of dying cells in their hearts by a large margin, the researchers said.

Periostin is abundant during fetal heart development, and increased amounts are also produced after injuries to skeletal muscles, blood vessels and bones. The researchers said a periostin patch placed near the site of a heart attack may prompt heart tissue to regrow.

The Boston team said a patch delivering the protein can be inserted through a catheter, directly through the skin or during heart surgery for other problems to treat adults after heart attacks, and children with congenital cardiac problems to strengthen the heart muscles.

The study is published in the July 15 online edition of Nature Medicine.