This latest research provides the most dramatic and clear-cut demonstration to date of heart cell regeneration after cardiac injury. Anversa and colleagues found that compared with a control group of 10 normal hearts, the rate of cell division in diseased hearts occurred at rates 70 times higher in the zone around the damaged part of the heart and 24 times higher in an area distant from the muscle damage. The researchers' main measure for cell division was measuring the amount of a protein called Ki67 that is expressed by cells throughout their life cycle, but at elevated levels when cells are dividing. They also made images of cells that were dividing and other cellular structures that are indicators of a cell splitting. Now, Anversa said, the key is to find the source of those dividing cells.
Stem cells are essentially unformed spare parts the body keeps around various organs.
They can differentiate and divide into more specialized cells as needed. But so far, cardiac stem cells haven't been identified. If we can prove the existence of cardiac stem cells and make these cells migrate to the region of tissue damage, we could conceivably improve the repair of damaged heart muscle and reduce heart failure. Biologists are becoming convinced that there are at least some of the adult stem cells for all parts of the body. Stem cells have recently been found in the brain, for instance, another organ once thought to stop growing new cells fairly early in life.