Conventional wisdom holds that a damaged heart cannot repair itself after a heart attack because the heart does not have the ability to produce new cardiac muscle cells throughout life. But now scientists have demonstrated that cardiac muscle cells are being replaced throughout life, though at a very slow rate - only about 1% of the heart muscle cells are replaced each year in young adults. The rate falls gradually to about half a percent per year by age 75. Over a lifetime, though, about 45% of the cardiac muscle cells present at birth will have been replaced.
One percent per year is not fast enough for the heart to repair itself under natural conditions after a heart attack. But the fact that it occurs at all is giving researchers new hope. If future research were to improve our understanding of how cardiac muscle cell replacement is regulated, perhaps new drugs or treatments could be developed that would jump-start the process after a heart attack.
It could be decades before any patients are actually helped by the new findings, but that’s the way science goes…..a little breakthrough here, a little breakthrough there, and pretty soon there’s real progress!
Minggu, 19 April 2009
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