Effects of Gammalinolenic Acid on Interleukin-1β and Tumor Necrosis Factor-α Secretion by Stimulated Human Peripheral Blood Monocytes: Studies in Vitro and in Vivo

Background Oils enriched in gammalinolenic acid, an unsaturated fatty acid, reduce joint pain and swelling in patients with rheumatoid arthritis. The cytokines interleukin-1β and tumor necrosis factor-α appear to contribute directly to joint tissue damage in patients with rheumatoid arthritis. Agents designed to interfere with the actions of interleukin-1β and tumor necrosis factor-α are being used to treat rheumatoid arthritis. Methods We examined the influence of gammalinolenic acid added to cells in vitro and administered orally in vivo on interleukin-1β and tumor necrosis factor-α secretion from activated human peripheral blood monocytes. Secretion of both cytokines was reduced by gammalinolenic acid. Administration of safflower oil as a polyunsaturated fatty acid control devoid of gammalinolenic acid did not change secretion of either cytokine. Conclusion Suppression of IL-β and TNF-α secretion by activated cells may be one mechanism whereby gammalinolenic acid suppresses synovitis in patients with rheumatoid arthritis.