The picture on the left shows green c-kit+ precursor stem cells within an infarct (lower right) in a three-day old mouse. These cells are becoming new myocytes and also new vessels. On the right is another image of a heart taken after three months showing a small residual scar (on bottom) remaining from what was an infarct, and new myocytes (red areas) throughout the region. Image: Kotlikoff Lab
In a two-day-old mouse, a heart attack causes active stem cells to grow new heart cells; a few months later, the heart is mostly repaired. But in an adult mouse, recovery from such an attack leads to classic after-effects: scar tissue, permanent loss of function and life-threatening arrhythmias.
A new study by Cornell and University of Bonn researchers found that stem cells did not create new heart cells in adult mice after a heart attack, settling a decades-old controversy about whether stem cells play a role in the recovery of the adult mammalian heart following infarction — the leading cause of sudden death in the developed world — where heart tissue dies due to artery blockage.
“If you did have fully capable stem cells in adults, why are there no new heart cells after an infarct? And is this due to the lack of stem cells or due to something special about the infarct that inhibits stem cells from forming new heart cells?” asked Michael Kotlikoff, the Austin O. Hooey Dean of Cornell’s College of Veterinary Medicine, and senior author of the paper appearing Aug. 29 in the Proceedings of the National Academy of Sciences. Via Study: Heart repairs very early in life, but not as adults.
