TRP Receptors in Arthritis, Gaining Knowledge for Translation from Experimental Models

Abstract

Arthritis is a condition characterised by mainly pain, reduced joint movement and signs of inflammation, such as swelling. The disorder has many different types, of which osteoarthritis (a degenerative joint disease) and rheumatoid arthritis (a chronic autoimmune disease) are the two most common forms. There are >6 million sufferers in the UK and both conditions have a huge potential to impair capabilities and contribute to social and economic burdens. Whilst there are a wide range of arthritic therapies available, many patients under treatment complain of poor pain relief. Thus there is a need for novel therapeutic approaches, and the transient receptor potential (TRP) family of receptor channels has been investigated. One particular area of recent research has been the ligand-gated transient receptor potential vanilloid 1 (TRPV1) channel. Findings from numerous pre-clinical models and scientific studies have shown that TRPV1 desensitisa- tion, or the use of TRPV1 antagonists alleviates pain and some inflammatory aspects. New findings have started to unveil the potential of other TRP channels in mediating arthritic pain and inflammation. With the understanding that the cur- rently available treatments for arthritis are limited, researchers have looked into the exciting prospect that TRP receptor antagonists may be developed into effective, specific drugs, which would potentially protect against the complications of arthritis. These antagonists are still under development, although only data from studies from pre-clinical models are cur- rently available. This review acts to summarize knowledge of the potential influence of TRP receptors in arthritis to date.