Tissue Regeneration Powers Identified in Tendon Stem Cells

University of Souther California, September 10, 2007

The professional career of an athlete can end with an injury that results in a damaged tendon, most athletes know this well.  But, a new type of unique cell has been identified that has the ability to proliferate and self-renew.  The cells were found within the adult tendon and have stem cell characteristics.  Songtao Shi, a University of Southern California (USC) School of Dentistry researcher, led a consortium of scientists on this particular project.

In an animal model, tendon-like tissue was regenerated after the research team successfully isolated the cells.  Tendon injuries caused by trauma or overuse could potentially be treated thanks to the discovery.  The promise is tremendous for clinical applications.

Comprised of strong collagen fibrils that transmit force allowing the body to move, tendons are tough bands of specialized tissues that connect muscle to bone.  Compared to undamaged tendon, tissue that is damaged rarely regains the strength and integrity it once had when normal.  The tissue heals slowly and tendon injuries are a common clinical problem.

"Clinically, tendon injury is a difficult one to treat, not only for athletes but for patients who suffer from tendinopathy such as tendon rupture or ectopic ossification," Shi says. "This research demonstrates that we can use stem cells to repair tendons. We now know how to collect them from tissue and how to control their formation into tendon cells."

Little was known about the tendons and their precursors as well as their cellular makeup prior to this research.  When guided by a certain molecular environment, the tendon stem/progenitor cells (TSPCs) in both mice and adult humans, form into tendon cells.  The research team was able to identify these unique TSPC cells by observing tendons on a molecular level.  The team included leading scientists from the University of Maryland School of Medicine, Johns Hopkins University, and the National Institute of Dental and Craniofacial Research at the National Institutes of Health.

Numerous studies on the role of stem cells in regeneration have been published by Songtao Shi, a researcher for USC's Center for Craniofacial Molecular Biology, a Division within the USC School of Dentistry.  In order to restore tooth function in an animal model, Shi and an international research team successfully generated tooth root and supporting periodontal ligaments.  Shi and his team discovered that mesenchymal stem cells are capable of regenerating facial bone and skin tissue in the mouse and swine models earlier this year.  The research was published in the journal Stem Cells.

The journal Nature Medicine will publish the current work on their October 2007 issue, the report will also be posted online on September 9th, 2007.

The National Institutes of Health and the USC School of Dentistry funded the study.

Reference: Yanming Bi, Driss Ehirchiou, Tina M Kilts, Colette A Inkson, Mildred C Embree, Wataru Sonoyama, Li Li, Arabella I Leet, Byoung-Moo Seo, Li Zhang, Songtao Shi & Marian F Young. "Identification of tendon stem/progenitor cells and the role of the extracellular matrix in their niche." Nature Medicine, October 2007.