Researchers funded by the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS) have identified a new method to diagnose and monitor cartilage changes in people with osteoarthritis (OA). Their discovery, which was reported in the Proceedings of the National Academy of Sciences, holds promise for interventions to preserve joint function in individuals identified at early stages of the disease.

Osteoarthritis is caused by the breakdown of cartilage, the tissue that covers the ends of bones where they meet to form a joint. People with OA often experience pain and loss of movement in their joints. Treatment approaches focus on reducing pain, improving mobility, and slowing the progression of the disease.

Although radiographs (x-rays) have traditionally been used as the diagnostic tool for OA, these tests do not show damage from the disease until significant cartilage loss has taken place. Newer imaging techniques also have limitations, including their reliance on contrast dye injections, which can be problematic for older people and those with kidney disease. In light of these issues, Ravinder Regatte, Ph.D., and researchers from New York and Tel Aviv Universities have developed a new method to detect early and progressive changes in cartilage tissue.

Regatte's work focused on proteoglycans, molecules that serve as building blocks for cartilage. "The loss of proteoglycans from cartilage appears to be the initiating event in OA," says Regatte. He and his team adapted an established magnetic resonance imaging (MRI) technique to separately visualize proteoglycans from water molecules in tissue samples of knee cartilage and intravertebral discs. Through a series of experiments, they demonstrated that their method provided accurate measurements of proteoglycans that were as reliable as measurements from more sophisticated and invasive technologies. And, unlike other imaging methods, Regatte's approach did not involve the use of a contrast agent, making it a safer diagnostic tool.

Although further research and refinements are needed, Regatte is hopeful that this non-invasive approach could one day play an important role in the management of people with OA. "Early detection is the key to preventing damage and disability from osteoarthritis, and could allow clinicians the opportunity to monitor the impact of therapeutic interventions very early in the disease process. Such an approach could result in a significant reduction in health care costs from joint replacement surgery."

The mission of the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), a part of the Department of Health and Human Services' National Institutes of Health, is to support research into the causes, treatment and prevention of arthritis and musculoskeletal and skin diseases; the training of basic and clinical scientists to carry out this research; and the dissemination of information on research progress in these diseases. For more information about NIAMS, call the information clearinghouse at (301) 495-4484 or (877) 22-NIAMS (free call) or visit the NIAMS Web site at

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Ling W, Regatte RR, Navon G, Jerschow A. Assessment of glycosaminoglycan concentration in vivo by chemical exchange-dependent saturation transfer (gagCEST). Proc Natl Acad Sci U S A. 2008 Feb 19;105(7):2266-70. Epub 2008 Feb 11. PMID: 18268341

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