Towards a resolution of chronic arthritis pain

What is it about?

Pain is a persistent symptom of rheumatoid arthritis (RA). It is often one of the first symptoms that people experience, and it remains even after suppression of joint disease with current medicines. This pattern of dissociation between pain and inflammation implies that other mechanisms, outside of the joint, make an important contribution to the person’s pain. Current medicines control swelling and reduce to a certain degree pain that however remains to a significant level. With this study we define a mechanism for chronic pain and provide novel targets for treatment of RA pain. Pain and swelling are signs of RA, where blood cells enter the joint and produce factors that cause swelling and activate pain nerves: these nerves carry pain signals from the joint to the spinal cord on their way to the brain where pain is felt. We discovered that blood-derived cells are not only in the joint, but they are also around pain cells outside the joint in a structure that is called dorsal root ganglia (DRG). At this DRG site, far away from the swollen joint, blood-derived cells influence pain cells and favour pain sensation. In these blood-derived cells we have identified new targets that can be exploited to regulate pain cell activity and constitute novel approaches to treating RA pain even when joint inflammation is under control. We propose blood-derived cells produce chemicals that increase pain sensitivity and have identified a way to stop such production and increase production of chemicals that can reduce pain.

Featured Image

Photo by Towfiqu barbhuiya on Unsplash

Photo by Towfiqu barbhuiya on Unsplash

Why is it important?

We have delineated a novel mechanism by which blood-derived cells regulate the activity of pain cells and believe that this discovery enables the development of innovative and improved treatments. In fact, molecules that induce pain relief may be possible targets for future drug development. As such, fat-like messenger molecules called lipids, which play a role in the modulation of pain sensitivity, are potential targets. The possibility of modulating newly identified targets in blood-derived cells represents a novel treatment strategy for RA pain, with the potential to relieve pain where traditional and biologic disease modifying treatments have proved not to be sufficient.

Perspectives