Heart can repair itself, say researchers

Challenging generations of medical lore, researchers have found striking new evidence that the human heart can repair itself.

Doctors have long assumed that damage from a heart attack or other ailment is irreversible and that the heart cannot regenerate tissue like other organs. But recent research has changed that.

A team of American and Italian researchers demonstrated last year that heart muscle cells multiply after a heart attack. Now they have shown that in heart transplant patients, primitive cells from the patient travel to the new heart and grow new muscle and blood vessels.

The researchers studied men who received transplanted hearts from women, and discovered male cells in the donated female hearts.

The discovery could help scientists eventually devise treatments to fix bad hearts.

"There have been hints from animal studies that the cells could migrate before, but this is the first demonstration in a human that it is actually possible," said John Fakunding of the National Heart, Lung and Blood Institute, which helped pay for the study in Thursday's New England Journal of Medicine.

The researchers found that heart muscle and blood vessels grew rapidly in the new hearts after transplant. They calculated that as much as one-fifth of the donor heart had been rebuilt by the recipient's own cells.