Time-dependent changes in retinoids content in liver and adipose tissue after feeding of a vitamin A-deficient diet to mice

Vitamin A is an important nutrient for multiple physiological functions. To elucidate the role of vitamin A in vivo, vitamin A-deficient diets have been often used in mice to establish a vitamin A-deficiency model. However, the information on the appropriate feeding periods and time course of changes in vitamin A content in organs after the start of vitamin A-deficient diet feeding is lacking. This study aimed to assess the retinoids levels in liver and white adipose tissue in mice fed a vitamin A-deficient diet for £8 weeks. High-performance liquid chromatography was used to measure the retinoids levels in liver and white adipose tissue every 2 weeks for £8 weeks. Vitamin A-deficient diet feeding significantly decreased retinol in the liver over 6 weeks, but retinyl palmitate, a main storage form of vitamin A, was not changed over 8 weeks. The plasma retinol level remained constant throughout the experiment. In white adipose tissue, retinyl palmitate gradually decreased over 8 weeks. These results indicate that vitamin A-deficient diet feeding longer than 6 weeks reduced retinol in liver and retinyl palmitate in white adipose tissue over 8 weeks, although it is not enough for the induction of a whole-body vitamin A deficiency.

White adipose tissue undergoes browning during preweaning period in association with microbiota formation in mice

Beige adipocytes are transiently induced during early postnatal period in mice. Previous studies have suggested that, unlike in adults, the induction is independent of the sympathetic nerve activity; however, the mechanism is yet unknown. Here, we showed that beige adipocytes are induced during the preweaning period in association with the formation of microbiota in mice. Alteration of gut microbiota composition in preweaning mice by maternal treatment with antibiotics or high-fat diet feeding substantially suppressed WAT browning. The suppression was also found in pups transplanted cecal microbiota from pups of high-fat diet-fed dams. These treatments reduced the hepatic expression of genes involved in bile acid synthesis and the serum bile acids level. The abundance of Porphyromonadaceae and Ruminococcaceae in microbiota showed a positive and negative correlation with the induction of beige adipocytes, respectively. This finding may provide comprehensive understanding of the association between gut microbiota and adipose tissue development in the neonatal period.