The Effects of Aging on Mouse Tendon Stem Cells

INTRODUCTION Aging leads to a decline in the functional competence of human bodies as well as to degenerative changes in connective tissues such as tendons. Aging tendons lose the integrity of their matrix and mechanical strength. However, the precise cellular mechanisms responsible for the detrimental effects of aging on tendons are unknown. We recently identified tendon stem cells (TSCs) in rabbits and mice [1, 2]. TSCs possess multi-differentiation potential; namely, they can not only differentiate into tenocytes under normal physiological conditions but also non-tenocytes (e.g. adipocytes, chondrocytes, and osteocytes) under aberrant conditions. Aging could be one such aberrant condition for tendons. Therefore, we aimed in this study to test the hypothesis that with aging, the number of TSCs decreases and TSCs tend to differentiate toward non-tenocytes.