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Cell regrowth may be enough to mend
hearts
By Steve Sternberg, USA TODAY
Scientists have found the best evidence
yet that, contrary to prior belief, heart muscle cells can
multiply, says a study out Thursday.
The finding opens the door to treatments
that spur cell division and restore healthy heart muscle.
Indeed, the study suggests that the heart could produce enough
new cells to repair itself.
"A heart attack that kills 40% of heart
muscle cells could be repaired if regeneration continues 20
days," says lead investigator Piero Anversa of New York
Medical College in Valhalla.
By cutting off the heart's blood supply,
heart attacks destroy muscle. The heart repairs the damage by
replacing damaged muscle with scar tissue, which cannot
contract to pump blood. The heart's inability to lay down new
muscle cells appeared to support the decades-old belief that
heart muscle cells stop dividing by age 9.
Two years ago, Anversa captured images of
cells dividing in hearts removed from transplant recipients.
Now he has shown that the muscle cells also multiply after
heart attacks.
In a study published in Thursday's New
England Journal of Medicine, Anversa used a powerful
microscope to examine heart muscle cells taken from 13
patients who had suffered heart attacks four to 12 days
earlier. He focused his lens on muscle cells at the border of
the heart attack and cells taken from a more distant location.
He compared the cells with those taken from 10 people without
heart disease.
The difference was striking. In heart
patients, Anversa found 70 times as much cell division in the
"border zone" of their diseased hearts and 24 times as much in
the more remote location than he measured in the control
patients.
But many obstacles must be eliminated
before the finding can lead to new treatments. Since heart
attacks kill heart muscle cells, new cells won't grow where
the heart needs them the most. Researchers must find a way to
provoke multiplying cells to migrate to the damaged area
before scar tissue forms. Scientists must then find a way to
sustain their growth.
"I think this does offer the potential
for limiting damage from heart attacks," says John Fakunding
of the National Heart, Lung, and Blood Institute. Emergency
treatment can prevent people from dying of heart attacks, he
says, but doctors can't keep heart disease from leading to
heart
failure. | 
