The medical community has long thought the heart muscle had zero regenerative ability; once it was damaged or otherwise made ineffective, there was no chance of the body making new cells to replace the old ones. That way of thinking is about to change, however, thanks to a new study from Vanderbilt University.
Cardiac stem cells, cells that can create new heart muscle, have been identified inside arteries. The discovery came about as scientists closely examined endothelial cells that line the inner surface of blood vessels. These cells have been known to generate other cells types during mammalian development.
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“People thought that the same heart you had as a young child, you had as an old man or woman as well, said researcher Antonis Hatzopoulos in a press release. “Our study suggests that coronary artery disease could lead to heart failure not only by blocking the arteries and causing heart attacks, but also by affecting the way the heart is maintained and regenerated.”
What Hatzopoulos and his team suggest is that while the body is healthy and the heart is functioning at a normal level, the cardiac stem cells in the arteries maintain the heart muscle, regenerating cells as needed. When illness like coronary artery disease or a medical emergency like a heart attack occur, these stem cells stop making healthy muscle tissue and start making scar tissue instead. This switch can further complicate heart failure by creating another way arteries become blocked.
“It looks like the same endothelial system generates myocytes (muscle cells) during homeostasis and then switches to generate scar tissue after a myocardial infarction. After injury, regeneration turns to fibrosis, said Hatzopoulos. “If we can understand the molecular mechanisms that regulate the fate switch that happens after injury, perhaps we can use some sort of chemical or drug to restore regeneration and make muscle instead of scar. We think there is an opportunity here to improve the way we treat people who come into the clinic after myocardial infarction (heart attack).
The key in future research will be to uncover why the cardiac stem cells in the arteries switch from making healthy cells to making scar tissue cells. By learning to control this switch, experts may be able to one day encourage the body to make new heart tissue after a heart attack or to combat age and other disease issues.