Fish nutrients decrease expression levels of tumor necrosis factor-α in cultured human macrophages

Rudkowska I, Marcotte B, Pilon G, Lavigne C, Marette A, Vohl MC. Fish nutrients decrease expression levels of tumor necrosis factor-alpha in cultured human macrophages. Physiol Genomics 40: 189-194, 2010. First published December 1, 2009; doi:10.1152/physiolgenomics.00120.2009.-Numerous studies have demonstrated the beneficial effects of fish consumption on inflammatory markers. Until now, these beneficial effects of fish consumption have been mostly linked to the omega-3 fatty acids (FA). The objective of the present study was to examine, in vitro, whether expression levels of genes involved in the inflammatory response differ in human macrophages incubated with casein hydrolysates (CH) or fish protein hydrolysates (FPH) in the presence or absence of omega-3 FA compared with omega-3 FA alone. Peripheral blood monocytes differentiated into macrophages from 10 men were incubated in the presence of omega-3 FA (10 mu M eicosapentaenoic acid and 5 mu M docosahexaenoic acid) or CH or FPH (10, 100, 1,000 mu g) with or without omega-3 FA for 48 h. Results demonstrate that expression levels of tumor necrosis factor alpha (TNF alpha) had a tendency to be lower after the addition of FPH alone or CH with omega-3 FA compared with omega-3 FA treatment. Furthermore, the combination of FPH and omega-3 FA synergistically decreased expression levels of TNF alpha compared to treatment with omega-3 FA or FPH alone. No difference on gene expression levels of interleukin-6 was observed between treatments. In conclusion, these preliminary results suggest that the anti-inflammatory effects of fish consumption can be explained by a synergistic effect of the omega-3 FA with the protein components of fish on TNF alpha expression and therefore contribute to the beneficial effects of fish consumption. Hence, follow-up studies should be performed to confirm the effects of a diet rich in FPH and omega-3 FA on serum proinflammatory cytokine concentrations.