Public Release: 

Stem Cell Implants Show Promise For Treating Torn Tendons

University of Cincinnati

Cincinnati -- People who suffer serious tendon injuries like President Clinton's might recover more quickly and more completely using a new treatment being tested by researchers in the University of Cincinnati College of Engineering. The treatment was developed by Osiris Therapeutics, Inc. of Baltimore.

The treatment is based on human mesenchymal stem cells, embryonic-like cells responsible for the formation of cartilage, bone, muscle, tendons, ligaments and other connective tissue. Osiris is developing therapies using a patient's own stem cells to regenerate tissue damaged by injuries or disease. Normally, the healing process is very slow and inefficient because there are so few stem cells available.

Preliminary research results using animal models indicate that stem cell implants dramatically reduce the time required for healing following tendon surgery. Randell Young, the manager of preclinical studies for Osiris, said experiments showed "a significant increase in tendon repair strength as early as four weeks after surgery" with continued improvement up to 12 weeks after surgery.

David Butler, a professor of engineering mechanics at the University of Cincinnati, found that stem cells could regenerate about two-thirds of normal tendon strength within four weeks. The re-grown tendon could also absorb nearly the same amount of energy as a normal tendon. More important, the quality of tissue was good. "It was a rapid improvement in both quality and quantity of tissue," said Butler.

The preliminary results were reported at the annual meeting of the Orthopaedic Research Society in San Francisco. The next phase of the research will focus on the patellar tendon and the Achilles tendon, because those two tendons are subjected to the greatest amount of force. And as President Clinton will find, the normal recovery time is typically quite long.

"It's going to be debilitating for him," said Butler. "it will be six weeks to three months of rehab. Jogging? He's done with that for quite some time, at least six months."

There are over half a million injuries in the United States each year to patellar, quadriceps, Achilles and rotator cuff tendons. Those numbers are likely to increase in coming years as the number of older Americans increases. "Age is a factor," said Professor Ed Grood, who collaborates with Butler in the Noyes-Giannestras Biomechanics Laboratory at UC. "As you get older, your ligaments and tendons get weaker. They're more susceptible to injury."

The National Institutes of Health just awarded Osiris a two-year $750,000 Small Business Innovation Research (SBIR) grant to continue development of the treatment in collaboration with the University of Cincinnati researchers.

Osiris President and CEO James Burns said he's encouraged by the progress made so far on the research and said the large SBIR grant indicates the National Institutes of Health believes stem cell implants are a promising approach. "The ability to restore patient function to normal within one to two months would provide a substantial breakthrough in the treatment of soft tissue injuries," said Burns.

A key to using mesenchymal stem cells is the way they are implanted into the body. Researchers have found that the cells respond not only to chemical signals inside the body, but also to physical stresses. Therefore, Osiris has developed customized implants which maximize the quality and quantity of new tissue produced. Osiris researchers are also exploring the use of mesenchymal stem cells to regenerate bone, cartilage and muscle.

Human studies are awaiting FDA approval.

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