Prevention and reversal of lipotoxicity-induced hepatic insulin resistance and steatohepatitis in mice by an antioxidant carotenoid, β-cryptoxanthin

Endocrinology. 2015 Mar;156(3):987-99. doi: 10.1210/en.2014-1776. Epub 2015 Jan 6.

Abstract

Excessive hepatic lipid accumulation promotes macrophages/Kupffer cells activation, resulting in exacerbation of insulin resistance and progression of nonalcoholic steatohepatitis (NASH). However, few promising treatment modalities target lipotoxicity-mediated hepatic activation/polarization of macrophages for NASH. Recent epidemiological surveys showed that serum β-cryptoxanthin, an antioxidant carotenoid, was inversely associated with the risks of insulin resistance and liver dysfunction. In the present study, we first showed that β-cryptoxanthin administration ameliorated hepatic steatosis in high-fat diet-induced obese mice. Next, we investigated the preventative and therapeutic effects of β-cryptoxanthin using a lipotoxic model of NASH: mice fed a high-cholesterol and high-fat (CL) diet. After 12 weeks of CL diet feeding, β-cryptoxanthin administration attenuated insulin resistance and excessive hepatic lipid accumulation and peroxidation, with increases in M1-type macrophages/Kupffer cells and activated stellate cells, and fibrosis in CL diet-induced NASH. Comprehensive gene expression analysis showed that β-cryptoxanthin down-regulated macrophage activation signal-related genes significantly without affecting most lipid metabolism-related genes in the liver. Importantly, flow cytometry analysis revealed that, on a CL diet, β-cryptoxanthin caused a predominance of M2 over M1 macrophage populations, in addition to reducing total hepatic macrophage and T-cell contents. In parallel, β-cryptoxanthin decreased lipopolysaccharide-induced M1 marker mRNA expression in peritoneal macrophages, whereas it augmented IL-4-induced M2 marker mRNA expression, in a dose-dependent manner. Moreover, β-cryptoxanthin reversed steatosis, inflammation, and fibrosis progression in preexisting NASH in mice. In conclusion, β-cryptoxanthin prevents and reverses insulin resistance and steatohepatitis, at least in part, through an M2-dominant shift in macrophages/Kupffer cells in a lipotoxic model of NASH.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Antioxidants / pharmacology
  • Cryptoxanthins / pharmacology*
  • Dietary Fats / administration & dosage
  • Dietary Fats / adverse effects*
  • Glucose / metabolism
  • Hepatic Stellate Cells
  • Homeostasis
  • Insulin Resistance*
  • Kupffer Cells
  • Liver / drug effects*
  • Liver / metabolism
  • Liver Cirrhosis
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Non-alcoholic Fatty Liver Disease / chemically induced*
  • Non-alcoholic Fatty Liver Disease / metabolism
  • Non-alcoholic Fatty Liver Disease / pathology
  • Obesity

Substances

  • Antioxidants
  • Cryptoxanthins
  • Dietary Fats
  • Glucose