Influence of intravenous n-3 lipid supplementation on fatty acid profiles and lipid mediator generation in a patient with severe ulcerative colitis

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Abstract
N‐3 fatty acids were supplied to a 36‐year‐old female patient suffering from ulcerative colitis and severe steroid side‐effects, in a sequence of parenteral and enteral administration. During a moderately active period of disease, 200 ml d‐1 fish oil‐derived lipid emulsion (eicosapentaenoic acid [EPA], 4–2 g; docosahexaenoic acid [DHA], 4.2 g) was infused for 9 days, in parallel with rapid tapering of the steroid dose. Disease activity declined rapidly, and the patient was subsequently provided with 16 fish oil capsules per day (EPA, 2.9 g; DHA, 1.9 g) for 2 months. At the end of this period of therapy, severe colitis recurred with intestinal and extraintestinal manifestations. The n‐3 lipid emulsion was then used for intravenous alimentation (29 days, maximum dose 300 ml per day); during this time, marked improvement of the inflammatory bowel disease was noted. During both periods of parenteral n‐3 lipid administration, total plasma EPA and DHA contents increased several‐fold, surpassing that of arachidonic acid; this plasma n‐3 fatty acid enrichment was only maintained to a minor extent during the intermediate period of dietary fish oil supplementation. The intravenously administered EPA‐containing triglycerides were rapidly hydrolyzed, as evidenced by the appearance of substantial quantities of EPA in the plasma free fatty acid fraction. Platelet and neutrophil total membrane content of EPA and DHA as well as n‐3 fatty acid/AA membrane ratios similarly increased during the periods of intravenous n‐3 lipid administration and declined during oral fish oil uptake. In contrast, erythrocyte membrane enrichment in EPA and DHA occurred only after the prolonged (2 month) period of dietary n‐3 lipid supplementation. Ex vivo stimulation of neutrophils with A23187 showed progressive increase in 5‐series leukotriene‐ and 5‐HEPE‐generation during both periods of n‐3 lipid infusion, in parallel with the rise of plasma EPA contents. Maximum 5‐series/4‐series leukotriene ratios surpassed 0.25. Similarly, ratios of thromboxane B3/B2 liberated from ex vivo stimulated platelets surpassed 0.4 during ongoing n‐3 lipid infusion. The profound changes in fatty acid profiles and lipid mediator generation may be related to the reduction in colitis activity observed during the periods of intravenous n‐3 lipid supplementation.