Mesenchymal stem cells in the aging and osteoporotic population.

Because of their ability to self-renew and differentiate, mesenchymal stem cells (MSCs) are the in vivo source for replacing lost cells in high-turnover tissues during the life of an organism. MSCs have osteogenic potential and can be eligible for the repair and maintenance of the skeleton, thus they are very attractive for tissue engineering and regenerative medicine approaches. However, many changes in their behavior, caused by aging and bone disease, have been reported in the literature. These changes, which affect MSC self-renewal ability and differentiation potentiality, are related to cell proliferation, differentiation, cell cycle phases (depending on gene modification), and cytokine and growth factor production. This review summarizes the literature related to intrinsic and extrinsic characteristics of human bone marrow or adipose tissue MSCs during aging and osteoporosis. Although some studies reveal contrasting results, the results of this review suggest that the cellular modifications due to aging and osteoporosis should be carefully considered in relation to the use of MSCs for therapeutic application.