Effects of capsaicin on the metabolism of rheumatoid arthritis synoviocytes in vitro

Capsaicin is substance found in hot (chili) peppers and it has been applied topically (directly to the skin) to patients as an experimental treatment for a variety of diseases. Experiments in animals demonstrated that capsaicin moderates the inflammation of the synovial membrane of joints. Tachykinins, also known as substance P, are polypeptides present in the synovial fluid that can be released by administration of capsaicin. Synovial tissue samples were obtained from patients with rheumatoid arthritis who were undergoing joint surgery. The cultures of these synovial cells (synoviocytes) were studied to determine if capsaicin administration would have direct beneficial effects for the treatment of patients with arthritis. Capsaicin had a direct effect on the metabolism of the synovial cells, it induced cell proliferation at low concentrations, and it increased the synthesis of collagenases and prostaglandins. The investigators believe that the modifications induced by capsaicin in rheumatoid arthritis synoviocytes were not mediated by tachykinins. Capsaicin was believed to act directly on synovial cells; however, the exact mechanisms still need to be determined. (Consumer Summary produced by Reliance Medical Information, Inc.)