BACKGROUND: Parenteral nutrition is often a mandatory therapeutic strategy for cases of septicemia. Likewise, therapeutic application of anti-oxidants, anti-inflammatory therapy, and endotoxin lowering, by removal or inactivation, might be beneficial to ameliorate the systemic inflammatory response during the acute phases of critical illness. Concerning anti-inflammatory properties in this setting, omega-3 fatty acids of marine origin have been frequently described. This study investigated the anti-inflammatory and LPS-inactivating properties of krill oil (KO)-in-water emulsion in human macrophages in vitro.

MATERIALS AND METHODS: Differentiated THP-1 macrophages were activated using specific ultrapure-LPS that binds only on the toll-like receptor 4 (TLR4) in order to determine the inhibitory properties of the KO emulsion on the LPS-binding capacity, and the subsequent release of TNF-alpha.

RESULTS: KO emulsion inhibited the macrophage binding of LPS to the TLR4 by 50% (at 12.5 microg/mL) and 75% (at 25 microg/mL), whereas, at 50 microg/mL, completely abolished the LPS binding. Moreover, KO (12.5 microg/mL, 25 microg/mL, or 50 microg/mL) also inhibited (30%, 40%, or 75%, respectively) the TNF-alpha release after activation with 0.01 microg/mL LPS in comparison with LPS treatment alone.

CONCLUSION: KO emulsion influences the LPS-induced pro-inflammatory activation of macrophages, possibly due to inactivation of the LPS binding capacity.