Immune activation by medium-chain triglyceride-containing lipid emulsions is not modulated by n-3 lipids or toll-like receptor 4

Toxicol In Vitro. 2015 Oct;29(7):1851-8. doi: 10.1016/j.tiv.2015.07.004. Epub 2015 Jul 7.


Background: Saturated medium-chain triglycerides (MCT) as part of the parenteral lipid regimen (50% MCT and 50% long chain triglycerides (LCT)) activate the immune system in vitro. Fish oil (FO)-derived n-3 fatty acids (FA) inhibit saturated FA-induced immune activation via a toll-like receptor (TLR)-4 mediated mechanism. We hypothesized that effects of parenteral MCTs on immune cells involve TLR-4 signaling and that these effects are modulated by n-3 FA that are present in FO.

Materials and methods: To test this hypothesis we assessed effects of addition of various commercially available mixed parenteral lipid emulsions, n-3 FA and of TLR-4 inhibition on MCT-induced human immune cell activation by evaluation of the expression of leukocyte membrane activation markers and reactive oxygen species (ROS) production.

Results: All MCT-containing lipid emulsions activated leukocytes by inducing changes in expression of membrane markers and stimulus induced ROS production, whereas MCT-free lipid emulsions lacked this effect. Moreover, addition of n-3 FA to LCT/MCT did not prevent MCT-induced immune activation. TLR-4 inhibitors did not distinctly modulate MCT-induced changes in immune function.

Conclusion: Taken together, these findings suggest that leukocyte activation by parenteral MCTs does not involve TLR-4 signaling and is not modulated by n-3 FA in FO-, but is exerted via different signaling pathways.

Keywords: Fish oil; Immune system; Medium chain triglyceride; Parenteral nutrition; Toll like receptor 4.

MeSH terms

  • Emulsions
  • Fatty Acids, Omega-3 / pharmacology*
  • Humans
  • Leukocytes / drug effects*
  • Leukocytes / metabolism
  • Micelles
  • Reactive Oxygen Species / metabolism
  • Toll-Like Receptor 4 / metabolism
  • Triglycerides / pharmacology*


  • Emulsions
  • Fatty Acids, Omega-3
  • Micelles
  • Reactive Oxygen Species
  • TLR4 protein, human
  • Toll-Like Receptor 4
  • Triglycerides