Ageing Muscle: the Role of Stem Cells, and Rejuvenation Approaches

Stem cells are are of central importance to the maintenance of muscle tissue. Stem cells known as satellite cells lie dormant within skeletal muscle tissue. When said muscle is damaged, these cells are roused, proliferating to produce new cells and regenerate the tissue.

In ageing muscle, this process is disturbed in two broad ways. Firstly, ageing causes surrounding cells to alter their signalling, which in turn wakes the satellite cells prematurely and exhausts the stem cell pool. The satellite cells themselves also accumulate defects, such as DNA damage, epigenetic changes, and reduced ability to clear cellular waste.

In the future, it should be possible to slow or reverse the decline of satellite cells, and it is likely that effective approaches will target both the extrinsic signals from the environment, and the intrinsic changes that occur within the satellite cells themselves. Some animal studies have also genetically restored satellite cells’ function ex vivo, and reimplanted them with some success.

While such interventions are not ready for widespread use in humans, there are well established ways of slowing muscle decline. Exercise has wide ranging benefits for maintaining muscle into old age, and these are at least partly mediated by satellite cells. There is also evidence to suggest that calorie restriction, even short term, may enhance muscle stem cell function.