Objectives: The aim of this study was to investigate putative different outcomes on the development of non-alcoholic fatty liver disease in mice using fat options regularly used in human nutrition.
Methods: Male C57BL/6 mice were fed a control diet, and four different high-fat diets (HFD: 40% calories from fat; Research Diet, Inc., New Brunswick, New Jersey, USA) for 16 and 30 wk. HFDs had different common fat sources, including trans-fat, non-trans-fat palm oil (Primex-Z), palm oil alone, and corn oil alone. Mice were sacrificed and samples were collected for analysis.
Results: Using an unprecedented combination of in vivo imaging with immunometabolic phenotyping, we revealed that a HFD induced a major increase in hepatic lipid droplet deposition compared with control mice, being significantly higher in Primex-Z-fed mice. All HFD mice had similar or less weight gain as control mice; however, Primex-Z ingestion led to a higher increase in adiposity index (~90% increase) compared with other fat sources. Gene expression of isolated liver immune cells revealed large changes in expression of several inflammatory pathways, which were also more elevated in Primex-Z-fed mice, including Tnf (~20-fold), Il1b (~60-fold), and Tgfb (2.5-fold). Immunophenotyping and in vivo analysis showed that the frequency of hepatic immune cells was also disturbed during different HFD contents, rendering not only Kupffer cell depletion, but also reduced bacterial arresting ability.
Conclusion: Different fat dietary sources imprint different immune and metabolic effects in the liver during consumption of an HFD. The present data highlighted that Primex-Z-a novel non-trans-fat-is not only able to damage hepatocytes, but also to impair liver ability to clear blood-borne infections.
Keywords: Diet; High-fat diet; Immune system; In vivo imaging; Liver; NAFLD; Steatosis.
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