Interactions between ω3 polyunsaturated fatty acids and arginine on nutritional and immunological aspects in severe inflammation

Background & Aims: Immune-enhancing diets (IEDs) contain a mixture of nutrients claimed to have immunological properties. Therefore, it seemed relevant to determine the effect of each of their components. The aim of this study was to examine the role of arginine (Arg) and omega 3 polyunsaturated fatty acids (omega 3 PUFAs) in the effect of an IED (Crucial (R)) in a validated rat model of inflammation induced by turpentine (TI). Methods: Forty-two rats were randomized into five groups: AL (ad libitum), TI-EN (TI + standard enteral nutrition (EN): Sondalis (R) HP), TI-EN-Arg (TI + standard EN + Arg in equimolar concentration to Arg in the IED), TI-M-IED (TI + modified IED containing the same omega 6/omega 3 ratio as in standard EN) and TI-IED (TI + Crucial (R)). Blood was sampled to determine CD25 receptor density on lymphocytes. TNF-alpha, IL-6 and .NO (production and expression) were evaluated on isolated macrophages. Mesenteric lymph nodes, spleen and liver were cultured for analysis of enterobacterial translocation and dissemination. Results: CD25 density was decreased after TI and was corrected in the TI-EN-Arg, TI-M-IED and TI-IED groups (p < 0.05). TI induced an alteration of macrophage mRNA expression of IL-6, TNF-alpha and iNOS, corrected in the TI-EN-Arg and TI-M-IED groups (p < 0.05), but not by the IED. Enterobacterial translocation was observed in all treated groups, nevertheless the amount tended (p = 0.054) to be lower in the TI-EN-Arg group. Conclusions: Arg and omega 3 PUFAs make a major contribution to IED effects, but our study shows interaction between them on macrophage reactivity. This indicates that the individual properties of each pharma-conutrient are not additive in IEDs. (C) 2010 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.