01-09-2003 | Original
ω-3 vs. ω-6 lipid emulsions exert differential influence on neutrophils in septic shock patients: impact on plasma fatty acids and lipid mediator generation
Published in: Intensive Care Medicine | Issue 9/2003
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Objective
To compare the effects of a conventional ω-6 lipid infusion and a fish oil based (ω-3) lipid infusion for parenteral nutrition on neutrophil function, lipid mediators, and plasma free fatty acids.
Design and setting
Open-label, randomized, pilot study in a university hospital medical intensive care unit and experimental laboratory.
Patients and participants
Ten patients with septic shock and eight healthy controls.
Interventions
Patients (five per group) requiring parenteral nutrition received intravenously either a ω-3 or a ω-6 lipid emulsion for a 10-day period.
Measurements and results
At baseline levels of plasma free fatty acids were elevated several-fold, including high concentrations of the ω-6 lipid precursor arachidonic acid (AA). Neutrophils isolated from septic patients displayed markedly reduced responsiveness to ex vivo stimulation, including lipid mediator generation [leukotrienes (LT), PAF], respiratory burst, and phosphoinositide hydrolysis signaling. Under the ω-6 lipid infusion regimen abnormalities in plasma free fatty acids and impairment of neutrophil functions persisted or worsened. In contrast, a rapid switch in the plasma free fatty acid fraction to predominance of the ω-3 acids eicosapentaenoic acid and docosahexaenoic acid over AA occurred in response to ω-3 lipid infusion. LTB5, in addition to LTB4, appeared upon neutrophil stimulation originating from these patients, and neutrophil function was significantly improved in the ω-3 lipid group.
Conclusions
ω-3 vs. ω-6 lipid emulsions differentially influence the plasma free fatty acid profile with impact on neutrophil functions. Lipid-based parenteral nutrition in septic patients may thus exert profound influence on sequelae and status of immunocompetence and inflammation.