Can Pain Cause Arthritis?
Mouse Study: Arthritis Gets Better when Joint/Spine Pain Loop Is Broken in Mice
The idea that pain can keep a disease going makes sense to pain expert Allan Platt, PA-C, of the Emory University School of Medicine.
"This is evidence you can actually reduce disease severity by treating pain," Platt tells WebMD. "It is an important discovery that changes in the joint happen because of signals in the pain loop."
Although Kyrkanides and colleagues are working on a gene therapy that could be used in humans, existing drugs already target relevant chemical signals along the pain circuit. One is the IL-1 blocker Kineret, used by adults with treatment-resistant rheumatoid arthritis. It is not approved for treating osteoarthritis. Because it dampens immune responses, it increases the risk of infections.
Kyrkanides suggests that such drugs might be most effective for osteoarthritis if injected directly into the point where the nerves from affected joints meet the spine.
"This would be quite feasible and one of the first things to try in a pilot study," says Guilak. He notes that Kineret is already being tested in patients with osteoarthritis -- but as a systemic or inside-the-joint treatment, not as a way to block the pain circuit.
"The beauty of this is it does not require the invention of new drugs, just new uses of existing medication," Kyrkanides says.
He predicts that in the future, the feedback-loop theory of osteoarthritis will change the way doctors treat the disease.
"This is a radical shift in our understanding of osteoarthritis," Kyrkanides says. "The big change here is pain treatment at the right targets has to be an integral part of the overall management of arthritis."
The Kyrkanides paper appears in the October issue of the journal Arthritis & Rheumatism.