Effects of a Prescription Omega-3 Fatty Acid Concentrate on Induced Inflammation

Controlled endotoxin infusion has been used widely as a model system to evaluate anti-inflammatory mediators and therapies in a controlled, in vivo setting. It is well established that infusion of bacterial endotoxin (also known as lipopolysaccharide or LPS) in humans results in a marked increase in inflammatory cytokines, most notably TNF-α, IL-1, IL-6 and IL-8, CRP, granulocyte colony stimulating factor (GCSF); eicosanoids, such as prostaglandin (PG) E2 and other mediators. Administration of endotoxin, even at a low dose (0.6 ng/kg) elevates circulating concentrations of inflammatory cytokines, and mimics the inflammatory effects of chronic diseases. This model has been used for decades and has proved to be safe and informative for evaluating anti-inflammatory therapeutic interventions on human inflammation and downstream consequences. Prolonged or chronic inflammation is involved in the etiology of several diseases such as cardiovascular disease (CVD), diabetes, rheumatoid arthritis, cancer, and neurodegenerative diseases such as Alzheimer's disease. The evidence base clearly demonstrates benefits of diet in ameliorating inflammation and reducing the burden of chronic disease. With respect to marine-derived omega-3 fatty acids and various markers of inflammation related to cardiovascular disease (CVD), both population studies and randomized controlled supplementation trials have yielded mixed results. It is well established that these omega-3 fatty acids are precursors of series-3 prostanoids, thromboxanes, 5-series leukotrienes, and novel lipid mediators such as resolvins and protectins that have anti-inflammatory effects. We hypothesize that supplementation of omega-3 fatty acids will blunt the response to an inflammatory stimulus and/or enhance the resolution phase. We propose to test this hypothesis using an in vivo endotoxin challenge with a pharmacological dose of omega-3 fatty acid ethyl esters (P-OM3, 3.4 g/d EPA + DHA) in healthy volunteers. Our proposed approach is novel in that we will provoke an in vivo inflammatory response by infusing human subjects with a low dose (0.6 ng/kg body weight) of sterile endotoxin (lipopolysaccharide \[LPS\]) in contrast to studies that have attempted to reverse established inflammatory pathology. Results from our proposed research will advance our understanding of the effect of omega-3 fatty acids on prevention/attenuation of an inflammatory response.