Short-term n-3 fatty acid supplementation but not aspirin increases plasma proresolving mediators of inflammation.

Resolution of inflammation is an active process involving specialized proresolving mediators (SPM) formed from the n-3 fatty acids. This study examined the effect of n-3 fatty acid supplementation and aspirin on plasma SPMs in healthy humans. Healthy volunteers (n = 21) were supplemented with n-3 fatty acids (2.4g/day) for 7 days with random assignment to take aspirin (300 mg/day) or placebo from day 5 to day 7. Blood was collected at baseline (day 0), day 5, and day 7. Plasma 18R/S-HEPE, E-series resolvins, 17R/S-HDHA, D-series resolvins, 14R/S-HDHA, and MaR-1 were measured by LC/MS/MS. At baseline concentrations of E- and D- series resolvins and the upstream precursors 18R/S-HEPE, 17R/S-HDHA ranged from 0.1nM to 0.2nM. 14R/S-HDHA was 3-fold higher than the other SPMs at baseline but MaR-1 was below the limit of detection. Supplementation with n-3 fatty acids significantly increased RvE1, 18R/S-HEPE, 17R/S-HDHA, and 14R/S-HDHA but not other SPMs. The addition of aspirin after 5 days of n-3 fatty acids did not affect concentrations of any SPM. N-3 fatty acid supplementation for 5 days results in concentrations of SPMs that are biologically active in healthy humans. Aspirin administered after n-3 fatty acids did not offer any additional benefit in elevating the levels of SPMs.