Inflammation & Omega-3 & Omega-6 Baste on 06 Feb 2007 12:49 pm
Fish Oil Reduces the Generation of Proinflammatory Biomarkers
Source: Critical Care Medicine (2007), 35: 544-554
Article Type: Original Contribution
Authors: MB Schaefer, J Ott, A Mohr, MH B, A Grosz, N Weissmann, S Ishii, F Grimminger, W Seeger K Mayer
Image taken from: http://doreen.mkbmemorial.com/NF/photos/ICU.JPG
Most intensive care patients are sooner or later affected by the systemic inflammatory response syndrome (SIRS). Hallmark of SIRS is the elevated production of certain eicosanoids possessing strong pro-inflammatory properties. Eicosanoids are derived from its precursor arachidonic acid, an omega-6 (n-6) fatty acid commonly found in biological membranes.
Arachidonic acid (20:4, n-6) in turn can be synthesizes from linoleic acid (18:2, n-6), the main fatty acid found in soy oil-based lipid emulsions, such as Lipoven (Fresenius Kabi, Germany). In contrast, cold water fish are rich in omega-3 fatty acids (especially eicosapentaenoic and docosahexaenoic acid), which are generally considered to show anti-inflammatory activity.
In their recent article, Schaefer et al. compare in a model of murine acute lung injury the inflammatory effect of Lipoven with that of the n-3-rich lipid formulation Omegaven (Fresenius Kabi, Germany). In agreement with previous reports, Lipoven promotes the production of pro-inflammatory biomarkers whereas the application of Omegaven leads to opposite effects. Here it is important to note that the impact of both formulations depends on the experimental design, i.e. the permanent infusion of the mice with the lipid emulsions. The authors point out that it is questionable whether the same effects could be provoked by oral intake of either lipid formulation.
Mechanistically, the article provides an interesting insight in the regulation of inflammation. Platelet-activating factor (PAF)-receptor knock-out mice (-/-) showed an inflammatory response comparable to those of wild type mice. However, neither Lipoven nor Omegaven were able to module the production of inflammatory biomarkers in PAF -/-, suggesting that both PAF and PAF-receptor are important for communicating the molecular signals exerted by n-3- and n-6.
In a nutshell, the administration of lipid emulsions might not only be means to supply the critically ill with enough energy, but also help to modulate the immune system towards pro- or anti-inflammatory response.
Another interesting report on the effect of n-3 in ICU patients can be found on the webpage of the Children’s Hospital Boston.