Mouse Study Clarifies Fish Oil Anti-Inflammatory Effect
ω-3 fatty acids stimulate an anti-inflammatory receptor found only on macrophages in fat cells
FRIDAY, Sept. 3 (HealthDay News) -- The ω-3 fatty acids found in fish oil are able to reduce obesity-related inflammation and insulin resistance by stimulating the anti-inflammatory effects of the G protein-coupled receptor 120 (GPR120), which is found only on pro-inflammatory macrophages in mature fat cells, according to a study in mice published in the Sept. 3 issue of Cell.
Da Young Oh, M.D., of the University of California San Diego in La Jolla, and colleagues put obese mice, including some mice genetically modified to lack the GPR120 receptor, on a high-fat diet. Some of the mice were given ω-3 fatty acid supplements and others were not, and the mice were observed for fat cell macrophage-mediated inflammation, a key factor in insulin resistance in obesity.
The researchers found that the ω-3 fatty acids, specifically docosahexaenoic acid (DHA) and eicosapentaenoic acid (EPA), exerted an anti-inflammatory effect by stimulating GPR120 to inhibit toll-like receptor (TLR) 2,3 and 4 and tumor necrosis factor (TNF)-α responses, enhancing insulin sensitivity in the normal mice. No anti-inflammatory effects were seen in the GPR120-deficient mice.
"In this report we show that GPR120 functions as an ω-3 fatty acid receptor/sensor in proinflammatory macrophages and mature adipocytes. By signaling through GPR120, DHA and EPA (the major natural ω-3 fatty acid constituents of fish oil) mediate potent anti-inflammatory effects to inhibit both TLR and TNF-α inflammatory signaling pathways," the authors write.