Study Backs Idea That Heart Can Repair Itself

By THE ASSOCIATED PRESS

hallenging 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 the way other organs can. But last year, a team of American and Italian researchers demonstrated that heart muscle cells multiplied after a heart attack.

And 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. Studying men who received transplanted hearts from women, the researchers discovered male cells in the donated female hearts — cells that could only have come from their own bodies.

"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. The institute helped pay for the study, which appears today in The 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.

"Clearly this shows that the heart has the ability to regenerate," said Dr. Roberto Bolli of the University of Louisville, who wrote an accompanying editorial. "It could be a milestone discovery if we learn how to exploit this phenomenon for therapeutic purposes to regenerate heart muscle in patients with heart failure."

After the heart recipients died, tissue samples were taken from each donor heart and from remnants of the old heart not removed during transplant surgery.

The researchers found evidence of the primitive cells with stem cell characteristics in the remnants of the old hearts, as well as in the donor hearts.

"We have the first strong suggestions that the heart has primitive cells — meaning cardiac stem cells — which could be used in the future to repair the heart," said Dr. Piero Anversa, who led the researchers at New York Medical College in Valhalla, N.Y., and the University of Udine and the University of Parma in Italy.

Dr. Anversa said he and his colleagues were working to identify whether a cardiac stem cell existed and whether it could be manipulated to promote heart repair.

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