More than 10% of the 27 million Americans who suffer from arthritis have the disease due to injury, that irritates and degrades the cartilage, causing a steady deterioration of joints, most often in the knee.
Research undertaken at MIT has identified a steroid drug commonly used to treat inflammatory diseases that could also prevent osteoarthritis from ever developing in those people, if given soon after the injury.
"In essence, it's repurposing an existing drug," says Alan Grodzinsky, senior author of the study, a professor of biological, mechanical and electrical engineering, and the director of MIT's Center for Biomedical Engineering.
Sports like basketball or skiing have a higher risk of tearing ligaments, such as the anterior cruciate ligament (ACL). Military service and car accidents are also common sources of joint injuries. Thus these types of injuries are more common in younger people, who are more active and or risk takers. Once damaged, the cartilage tends to degrade causing problems later in life, if not immediately.
In most cases, the injury is treated with non-steroidal anti-inflammatory drugs (NSAIDs) such as ibuprofen to reduce pain and swelling and if necessary weeks or months later, surgery maybe performed to fully stabilize the joint. However this type of more passive treatment is contradicted by the new MIT study.
The study published in the September 2 issue of the journal : Arthritis Research and Therapy is written by Grodzinsky and colleagues, including Yihong Lu, a recent MIT biological engineering PhD recipient, and Christopher Evans, the Maurice Edmond Mueller Professor of Orthopedic Surgery at Harvard Medical School.
The researchers used both human and bovine cartilage tissue which they damaged and then treated with inflammatory proteins called cytokines, which are typically released after a joint injury. Cytokines hasten cartilage breakdown.
The research showed that where damaged tissue is treated immediately with the glucocorticoid dexamethasone, cartilage breakdown was prevented. The drug also worked when given 24 - 48 hours after the injury, which is important because : "People who suffer joint injuries might not get to see a doctor right away," Grodzinsky says.
It is somewhat ironic that Doctors have been using glucocorticoids drugs, usually on more elderly patients with chronic rheumatoid arthritis, for decades now, but it has not been considered for immediate treatment of injuries.
Though admittedly the processes involved are not yet fully understood, the paper discusses how dexamethasone blocks the degradation of aggrecan, a protein-carbohydrate complex that is a major structural and biomechanically functional component of cartilage.
The research doesn't yet know if dexamethasone could reverse cartilage damage that has already occurred, but the scientists plan to test that in future studies. They also have plans to study animals with injuries in order to determine how many joint treatments would be necessary to maintain the protective effect.
"If those animal studies yield positive results, the findings could be rapidly translated to human treatments. Because the drug is already approved for human use."
Appropriate methods for drug delivery to localized joint cartilage is also a topic for future investigation.
If successful, the pending research would present a major change to the treatment of joint injuries, with a view to healing the damage, possibly avoiding the need for surgery and preventing chronic problems later on in life. It could in time cause a significant reduction in the number of people suffering from osteoarthritis.
By Rupert Shepherd BSc.