• Open Access

Tendon-derived stem/progenitor cell aging: defective self-renewal and altered fate

Authors


Dr Hui B. Sun and Dr Evan L. Flatow, Department of Orthopaedics, Box 1188, Mount Sinai, School of Medicine, One Gustave L. Levy Place, New York, NY 10029, USA. Tel.: +1(212) 241 3767; fax: +1(212) 876 3168; e-mail: herb.sun@mssm.eduorevan.flatow@msnyuhealth.org

Summary

Aging is a major risk factor for tendon injury and impaired tendon healing, but the basis for these relationships remains poorly understood. Here we show that rat tendon-derived stem/progenitor cells (TSPCs) differ in both self-renewal and differentiation capability with age. The frequency of TSPCs in tendon tissues of aged animals is markedly reduced based on colony formation assays. Proliferation rate is decreased, cell cycle progression is delayed and cell fate patterns are also altered in aged TSPCs. In particular, expression of tendon lineage marker genes is reduced while adipocytic differentiation increased. Cited2, a multi-stimuli responsive transactivator involved in cell growth and senescence, is also downregulated in aged TSPCs while CD44, a matrix assembling and organizing protein implicated in tendon healing, is upregulated, suggesting that these genes participate in the control of TSPC function.

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