Adult stem cells, also known as somatic stem cells, are found throughout the body in every tissues and organ after development and function as self-renewing cell pools to replenish dying cells and regenerate damaged tissues throughout life.
However, adult stem cells appear to age with the person. As stem cells age, their functional ability also deteriorates. Specifically, this regenerative power appears to decline with age, as injuries in older individuals heal more slowly than in childhood. For example, healing of a fractured bone takes much longer time in elderly than in young individuals.
There is a substantial amount of evidence showing that the deterioration of adult stem cells in the adult phase can become an important player in the initiation of several diseases in aging.