Why the human heart can’t regenerate itself
Washington: A new study has shed light on why adult human cardiac cells lose their ability to proliferate, perhaps explaining why our heart have little regenerative capacity.
The study, done in cell lines and mice, may lead to methods of reprogramming a patient``s own cardiac myocytes, or muscle cells, within the heart itself to create new muscle to repair damage, said Dr. Robb MacLellan, a researcher with the Eli and Edythe Broad Center of Regenerative Medicine and Stem Cell Research at UCLA and senior author of the study.
Recent research suggests that mammals do have the ability to regenerate the heart for a very brief period, about the first week of life. But that ability is quickly lost. But if we had it once, MacLellan said, maybe it is possible to regain that ability.
His study suggests that it might be possible to turn back the cellular clock to a time when cardiac myocytes had the ability to proliferate and re-grow heart muscle.
Animals like newts and salamanders, can spontaneously regrow damaged organs such as the heart at any point of their lives,” said MacLellan.
“In mammals, we``ve lost that potential. If we knew how to restore that, or knew the reason why adult myocytes can``t do it, we could try to figure out a way to use nature``s methods to regenerate the heart.”
During human development, cardiac myocytes are made by progenitor stem cells and proliferate to form the heart. Once the heart is formed, the myocytes transform from immature cells into mature cells that cannot proliferate.
That``s not so for newts and salamanders, whose cardiac myocytes can go back and forth between immature, or primitive, states to proliferate and repair damage and then revert back into mature cells once the damage is repaired.
MacLellan believes the reason adult human cardiac myocytes can``t do this is quite simple – when the myocytes are in a more primitive state, they are not as good at contracting, which is vital for proper heart function. Because humans are much larger than newts and salamanders, we needed more heart contraction to maintain optimum blood pressure and circulation.
The study was recently published in the peer-reviewed Journal of Cell Biology.