Metabolite profiling of mice under long-term fructose drinking and vitamin D deficiency: increased risks for metabolic syndrome and nonalcoholic fatty liver disease

Chronic fructose consumption and vitamin D deficiency (VDD) diet have been linked to the pandemic of metabolic syndrome (MetS) and nonalcoholic fatty liver disease (NAFLD). The metabolic mechanisms remain unclear. This study is to explore metabolic changes of mice fed with high fructose syrup and VDD diet in the biogenesis of MetS and NAFLD. C57BL/6J mice were treated with four conditions for 28 weeks: control (standard chow and sterile water), fructose drinking (FD, standard chow and 20 g/100 mL fructose in drinking water), VDD (standard chow with VD depleted and sterile water), and FD+VDD. Metabolites in the serum and liver of mice were analyzed by gas chromatography-mass spectrometry combined with trimethylsilyl derivatization. The histological results indicated that one-hit from long-term fructose drinking led to mild MetS, and a combination with VDD diet induced hepatic steatosis, inflammatory lesion, and interstitial fibrosis in mice, showing significant nonalcoholic steatohepatitis features. Metabolomics analysis showed significant changes in amino acids and short-chain organic acids in response to fructose drinking. VDD diet led to significant increase of hepatic fatty acids, which was consistent with the hepatic morphology of fat deposition. This work demonstrated a concert effect of FD and VDD in promoting MetS and NAFLD through changing in vivo metabolism and signaling pathways. And metabolomics analysis could provide early warnings for the biogenesis of MetS and NAFLD. Importantly, vitamin D supplementation in the diet can balance the metabolic disorders caused by excessive fructose intake.