The illustration shows a joint with severe osteoarthritis. Osteoarthritis wears away the cartilage at the ends of the bones. Spurs then grow out from the edge of the bone and synovial fluid increases, which may cause the joint to feel stiff and sore. Credit: The American Chemical Society
A newly developed medical-imaging technology may provide doctors with a long-awaited test for early diagnosis of osteoarthritis (OA), according to a recent report.
By far the most common form of arthritis, OA is a bane of the Baby Boom generation, causing joint pain and disability for more than half of those over 65—nearly 21 million people in the United States.
"Our methods have the potential of providing early warning signs for cartilage disorders like osteoarthritis, thus potentially avoiding surgery and physical therapy later on," said Alexej Jerschow, PhD, who discussed the research at a recent meeting with his colleague Ravinder R. Regatte, PhD. "Also, the effectiveness of early preventative drug therapies can be better assessed with these methods."
Diagnostic methods usually do not catch the disease until OA is in advanced stages when joint damage may already have occurred. A method for early diagnosis could open a window of opportunity for preventing or reducing permanent damage—especially with evidence that dietary supplements like glucosamine and chondroitin can halt further joint degeneration, Jerschow says.
Especially common in the knee and hip, OA damages cartilage, the tough, elastic material that cushions moving parts of joints. OA is the most common reason for total-hip and total-knee replacement surgery.
The new method uses a modified form of magnetic-resonance imaging to determine the concentration of a polymer known as glycosaminogycan (GAG) that holds lots of water and gives cartilage its properties. GAG also is a recognized biomarker for OA and degenerative disc disease—a common cause of back pain. According to Jerschow, a low concentration of GAG is known to correlate with the onset of OA and other cartilage disorders.
The diagnostic tags the hydrogen atoms attached to the GAGs in a way that makes them emit a signal that can be picked up by an MRI machine to determine the concentration of GAG and assess cartilage health.
Advanced OA is very easy to diagnose, Regatte says. By then, however, joint replacement may be the only option. With early detection, physicians could prescribe dietary supplements, medication, or other measures to ward off further cartilage damage.
"Given the lack of knowledge about OA, I think any method that is noninvasive and relatively easy to apply will be quite valuable. Not only do you address diagnosis, but you address how we can understand OA’s mechanism," Jerschow says.
The test could also be used to improve existing cartilage-boosting drugs, Regatte says. It is difficult to gauge the efficacy of these drugs without a diagnostic tool to measure their effects on cartilage.
"There are drugs on the market for OA treatment, but no one really knows how effective they are. After having done the research, we got a lot of calls from pharmaceutical companies wanting to show that their drugs work," Jerschow says.
The cost and time it takes for the cartilage test is practically the same as a normal MRI, Regatte says. Diagnosis could be given the same day.
"I really hope it will develop into the gold standard technique," Jerschow says. "I’m pretty confident in saying that its one of the better methods out there for testing cartilage health."
The New York-based scientists conveyed their research at a recent national meeting of the American Chemical Society, Washington. The organization is chartered by Congress and provides access to chemistry-related research through its multiple databases, peer-reviewed journals, and scientific conferences.