Can Pain Cause Arthritis?
Mouse Study: Arthritis Gets Better when Joint/Spine Pain Loop Is Broken in Mice
Sept. 29, 2008 -- Arthritis hurts, and that pain itself may be what keeps the disease going, mouse studies suggest.
When a pain signal from an arthritic joint reaches the spine, there's a burst of chemical signals, note University of Rochester researcher Stephanos Kyrkanides, DDS, PhD, and colleagues.
One result of this burst of signals is that the spine becomes inflamed in the area where the nerve from the joint attaches. Another result is that signals travel backward from the spine to the joint.
If that signal is interrupted, Kyrkanides and colleagues find, two things happen.
As might be expected, the joint is less painful. But to their surprise, Kyrkanides found that interrupting this joint/spine "cross talk" allows the joint to heal in mice with osteoarthritis.
"This cross talk is oil to the fire of arthritis," Kyrkanides tells WebMD. "Trying to stop joint inflammation with the traditional drugs we have is inadequate -- because it tries to address the joint but fails to address this newly discovered mechanism where pain is progressing along the nerve from the spine."
In studies with arthritic mice, the researchers used a gene therapy to block a chemical messenger, IL-1B. The mice stopped their pain behavior. And their joints got better.
"It proves the processing of pain in the joint actually contributes to arthritis itself," Kyrkanides says. "We were very impressed to see we could control arthritis progression and allow for spontaneous healing if, by targeting IL-1B, we could control the pain at the spinal cord or along the sensory nerves."
It's a "very exciting" finding, says osteoarthritis expert Farshid Guilak, PhD, professor of orthopedic surgery at Duke University.
"This can open up a whole new way of treating osteoarthritis by saying if you treat pain properly, you can affect the disease," Guilak tells WebMD. "That is opposite of what we say now. We worry if you just treat the pain, it can make the joint worse because the patient will overuse it. So if pain affects joint degeneration, it would point to very exciting ways to develop new treatments for arthritis."