Nuclear Fallout Solves Heart Mystery

Enlarge Mattias Karlen

By measuring the decay rate of carbon 14 in heart muscle cells, researchers were able to determine that these cells do in fact regenerate.

Mattias Karlen

By measuring the decay rate of carbon 14 in heart muscle cells, researchers were able to determine that these cells do in fact regenerate.

Can the atomic bomb tests of the Cold War lead to better treatments for heart attacks? Well, it's a bit of a stretch, but the answer may be yes.

Medical dogma says if you damage your heart muscle, either from injury or heart attack, those muscle cells will never grow back. The damage is permanent. But now a team of scientists in Sweden has shown that heart muscle cells do regenerate — just very, very slowly. And the researchers used fallout from the Cold War atomic bomb tests to prove it.

Atomic Fallout Stored In DNA

Ratan Bhardwaj and his colleagues at the Karolinska Institute in Stockholm studied carbon 14 levels in the DNA of heart muscle cells collected from cadaver tissue.

"The atomic bombs liberated a demonstrable amount of C14, which we could actually trace and see how old that cell is based on that," says Bhardwaj.

Heart Muscle Cells Regenerate — But Slowly

Using that data, Bhardwaj and his colleagues not only discovered that heart cells do replace themselves, but they also determined the regeneration rate.

The turnover rate isn't very fast: about a 1 percent turnover rate in a 20-year-old. "But the amazing thing is that level isn't zero, and that's what we didn't understand before," says Bhardwaj.

"The longstanding view is that the heart is one of the least regenerative organs in the body," says Chuck Murry, a stem cell biologist at the University of Washington. Murry says the new results don't really change that, but they do suggest some regrowth is possible.

A Better Heart Attack Treatment

Murry says there are two main implications from this research, which was published in the journal, Science. "The first is that heart muscle cells are very long lived, and difficult to replace and you're going to die with most of the cells you were born with, so you'd better take good care of them," he says.

"The second thing is the more optimistic note, since there is a little bit of turnover, if we can figure out how this works, we can exploit it therapeutically."

In other words, coax the heart into repairing itself after a heart attack or trauma.

That would be an unexpected bit of good news inspired by the Cold War atomic tests.