Stem Cells Improve Cartilage Repair for Arthritic Horses (AAEP 2010)

Osteoarthritis (sometimes called degenerative joint disease) is the most common cause of lameness in horses and currently there is no cure.1 However, researchers continue to improve available treatment methods. At the 2010 American Association of Equine Practitioners convention, held Dec. 4-8 in Baltimore, Md., Wayne McIlwraith, BVSc, PhD, DSc, FRCVS, Dipl. ACVS, director of the Orthopaedic Research Center at Colorado State University, presented the results of a study evaluating the use of bone marrow-derived stem cells in conjunction with microfracture for healing cartilage defects in horses.

Cartilage, a smooth layer of tough tissue covering the ends of bone at joints, allows the bones to move smoothly past each other as the joint moves. However, in osteoarthritis, that cartilage becomes thinned, roughened, or even worn completely away in spots by typical wear and tear, trauma, joint chips/debris, etc. Varying degrees of pain and lameness result.

Unfortunately cartilage doesn't spontaneously regenerate, but various treatments can help repair it to a degree. For the current study McIlwraith and colleagues used an experimental model of cartilage damage and a proven treatment of microfracture (punching small holes in the subchondral bone beneath the cartilage defect to stimulate cartilage growth). They then treated each lesion one month later with hyaluronan alone or hyaluronan with bone marrow-derived stem cells. Each horse also underwent a standardized daily treadmill exercise regimen from four to 12 months after the start of the study.

McIlwraith reported that using bone marrow-derived stem cells in addition to microfracture offered superior healing compared to microfracture alone. The repaired tissue was significantly firmer and had higher levels of aggrecan, a molecule that provides compressive stiffness to the cartilage.

"We've shown consistently better repair (of cartilage defects) with microfracture, and this is one step beyond that," said McIlwraith.



1 Oke S, McIlwraith W. Review of the Economic Impact of Osteoarthritis and Oral Joint-Health Supplements in Horses. Proceedings of the American Association of Equine Practitioners 2010, 12-16.

About the Author

Christy M. West

Christy West has a BS in Equine Science from the University of Kentucky, and an MS in Agricultural Journalism from the University of Wisconsin-Madison.

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