Successful heart muscle regeneration in mice may soon be seen in humans
A way to stimulate heart muscle cells to grow has been discovered by scientists from the Weizmann Institute of Science in Israel and the Victor Chang Institute in Sydney. Human blood, hair and skin cells renew themselves throughout life, but, cell division in the heart stops shortly after birth.
However, animals like the salamander and the zebrafish easily regenerate heart cells. They have an interesting mechanism that sends their cardiomyocytes, or heart muscle cells, into a dormant state, which when they come out of, go into a proliferative state, that is, they start dividing rapidly and replacing lost cardiomyocytes.
One of theories for why human cardiomyocytes do not regenerate explains that in a more primitive stage they are not as good at contracting. Since human hearts are larger than salamanders, we need to maintain optimum blood pressure and circulation for which proper contraction is vital. Hence, we do not have the ability to regenerate the heart muscle but we do have more efficient cardiac myocytes as a result.
Research suggests that mammals do have the ability to regenerate the heart for a very brief period, about the first week of life. A hormone neuregulin drives the signaling system in the heart which is responsible for proliferating of heart muscle cells. This hormone is usually blunted about one week after birth.
An author of the research, Prof. Richard Harvey and his colleagues, have uncovered a way to overcome the regenerative barrier in the rodents. They found that by stimulating hormone neuregulin, heart muscle cells divided in a spectacular way in both adolescent and adult mice. Also, triggering the pathway following a heart attack in the mice lead to replacement of lost muscle, and repaired the heart to a level close to that prior to the heart attack.
Prof.Harvey is hopeful that within five years it would be possible to replicate the results in humans. He believes that their significant findings will harness research activities in many labs around the world and spur work on maximizing the neuregulin-response. His team is now working on other ways to activate that pathway.
The research was led by molecular biologist Gabriele D’Uva and the findings were published in the scientific journal Nature Cell Biology.
