Novel lipid emulsion for total parenteral nutrition based on 18-carbon <i>n-3</i> fatty acids elicits a superior immunometabolic phenotype in the murine model compared to standard lipid emulsions

Abstract Background While lipid emulsions in modern formulations for total parenteral nutrition (TPN) provide essential fatty acids and dense calories, they also promote inflammation and immunometabolic disruptions. Objective We aimed to develop a novel lipid emulsion for TPN use with superior immunometabolic actions compared with available standard lipid emulsions. Methods A novel lipid emulsion (Vegaven, VV) containing 30% of 18-carbon n-3 fatty acids (α-linolenic acid and stearidonic acid) was developed for TPN (VV-TPN) and compared with TPN containing soybean oil-based lipid emulsion (IL-TPN) and fish oil-based lipid emulsion (OV-TPN). In vivo studies were performed in instrumented male C57BL/6 mice subjected to seven-day TPN prior to analysis of cytokines, indices of whole body and hepatic glucose metabolism, immune cells, lipid mediators and mucosal bowel microbiome. Results Interleukin-6 to interleukin-10 (IL10) ratios were significantly lower in liver and skeletal muscle of VV-TPN mice when compared with IL-TPN or OV-TPN. VV-TPN and OV-TPN each increased hepatic insulin receptor abundance and resulted in similar HOMA-IR (Homeostatic Model Assessment for Insulin Resistance) values, whereas only VV-TPN increased hepatic insulin receptor substrate 2 and maintained normal hepatic glycogen content, effects that were IL10-dependent and mediated by glucokinase activation. The percentages of interferon-γ- and interleukin-17-expressing CD4+ T-cells were increased in livers of VV-TPN mice, and liver macrophages exhibited primed phenotypes when compared with IL-TPN. This immunomodulation was associated with successful elimination of the microinvasive bacterium Akkermansia muciniphila from the bowel mucosa by VV-TPN as opposed to standard lipid emulsions. Assay of hepatic lipid mediators revealed a distinct profile with VV-TPN including increases in 9(S)-hydroxy-octadecatrienoic acid. When co-administered with IL-TPN, hydroxy-octadecatrienoic acids mimicked the VV-TPN immunometabolic phenotype. Conclusions We here report the unique anti-inflammatory, insulin-sensitizing and immunity-enhancing properties of a newly developed lipid emulsion designed for TPN use based on 18-carbon n-3 fatty acids.