In a First, Newborn Mice Regenerate Their Damaged Hearts

By Andrew Moseman | February 24, 2011 3:39 pm

Even with 15 percent of their hearts removed, newborn mice possess the extraordinary ability to mend themselves, researchers report today in the journal Science. It’s the first time that mammals outside of the womb have shown the regenerative ability to repair the heart.

Only newborn mice could regenerate part of their hearts, and they lost this ability after about a week after birth. Still, the results were quite impressive: Olson’s team removed 15 percent of the heart one day after birth, and when the researchers checked up three weeks later, the whole heart was repaired in 99 percent of the mice. Until now, scientists had seen fish and amphibians regenerate heart tissue as adults, but only embryonic mammals had been spotted doing the same.

“When a person has a heart attack and heart muscle cells are lost, the heart loses pump function, causing heart failure and eventual death,” said Eric Olson, a molecular biologist at Southwestern Medical Centre in Dallas, Texas. “Now that we know that the mammalian heart indeed possesses the potential to regenerate, at least early in life, we can begin to search for drugs or genes or other things that might reawaken this potential in the adult heart of mice and eventually of humans.” [The Guardian]

First they have to understand what the newborn rodent’s bodies are up to. Initially, Olson and colleagues weren’t sure how the mice were mending themselves—with stem cells, or cells that had already become muscle cells. But the appearance of the cells gave them away, says Dr. Stephen Badylak, who wasn’t involved in the study.

“A majority of the cells that contributed to regeneration were existing heart cells, not stem cells. That’s huge,” said Badylak. “That suggests that cells have been pulled out of the cell site. They’ve differentiated, [then] divide and form new cells.” “Now the question is maybe we can control this ability to regenerate at a site of interest,” he added. “If that’s possible, then the therapeutic potential is huge.” [HealthDay News]

What about the human heart? The first major step was this one, showing that a mammal’s heart could regenerate after birth. The next steps are to learn more about the process, and find out whether it is something that could lie dormant in humans.

It’s possible that newborn human hearts might also be able to regenerate, Porrello says. “There is some evidence that the newborn human heart does not scar following injury, suggesting that it might also be capable of regenerating during early life.” [New Scientist]

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Image: iStockphoto

CATEGORIZED UNDER: Health & Medicine
  • Yesenia

    Does this make the heart weaker as life goes on? How do the mice fare after they reach advanced maturity?

  • http://disqus.com/stonemason89 stonemason89

    Well, if you’re a mouse, I guess this beats getting caught in a mouse trap.

  • stemcellcure

    The similarly stunning results of Cephalon’s cardiac stem cell drug Revascor (just published in Nature) utilize the same mechanisms. It reduced MACE (Major Adverse Cardiac Events : chest pain, heart attack, death, etc) by an incredible 84%, virtually curing heart disease with one injection. If you can afford it, the drug has already been approved for treatment in Australia. http://bit.ly/i1pYmr

  • Dustin

    I gotta admit that it is a cool concept that mamals can self heal themselves. But seriously, why would we need a gene or a drug to allow us to do the same ? its screwing with the circle of life. People need to die. Its only natural. Like yes finding a cure would be an amazing breakthrough. But seeing as the population of earth is about 6.8 billion, and its engraved in stone ( in stonehenge i believe) that in order for earth to sustain stable life the population shall not exceed 500,000,000 Persons. Scientific developements could help us have an easier and longer life, but it could also cause this planet to be overpopulated much easier.

  • Matt B.

    How do they remove that much of the heart without causing immediate death?

    Dustin, I seriously doubt that there are any engravings at all on Stonehenge, much less that they had a way of writing a number as big as 500 million when the stones were put there around 4500 years ago.

  • Ashley

    The number 500,000,000 is engraved on the Georgia Guidestones and the only reason I know is that the show Decoded did a piece on them. I don’t agree with the stones though.

    I do agree that this research will make people live longer in the long run, and disrupt the ‘circle of life,’ but I think it’s very cool that the scientists found this out.

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