In vitro modulation of inflammatory cytokine production by three lipid emulsions with different fatty acid compositions

Abstract

Background & aims: Studies have suggested that 100% long-chain triacylglycerols (LCTs) lipid emulsions exhibit immunosuppressive effects, sometimes suspected to favor infectious complications in patients receiving parenteral nutrition. Newer emulsions, in particular olive oil-based emulsions, seem to have lesser immunosuppressive effects. We studied the in vitro effect of 100% LCTs (Intralipide®), 50% LCTs–50% medium chain triacylglycerols (Médialipide®), and 80% olive oil-based lipid emulsions (ClinOléic®) on inflammatory cytokines production by peripheral blood mononuclear cells (PBMCs).Methods: PBMCs separated by gradient centrifugation, or whole blood, were incubated with 0.001%, 0.01%, 0.1% and 1% of the three tested lipid emulsions during 24h in the presence or absence of activation by lipopolysaccharide and phytohemagglutinin. Then, supernatants were collected and cytokines measured (ELISA).Results: The three lipid emulsions reduced basal TNF-α and IL-1β production in PBMCs and whole blood cultures. However, ClinOléic® was significantly less powerful in TNF-α and IL-1β inhibition by isolated PBMCs than Intralipide® and Médialipide®. Basal TNF-α production was equally inhibited by the three emulsions in whole blood, but IL-1β production was not significantly modified by ClinOléic®. Interleukin-6 and -8 were not affected. After cell activation, lipid emulsions exhibit no effect on cytokines production.Conclusion: ClinOléic® induces a significantly lower in vitro inhibition of TNF-α and IL-1β production by PBMCs than 100% LCTs or 50% LCTs–50% MCTs emulsions, and therefore might be more immune neutral. These effects vary from one subject to another, and disappeared after cell activation. Therefore, caution must be taken before extrapolation in vivo. Provided information should be taken into account for future design of clinical trials studying the immune modulating properties of lipid emulsions.