Vitamin A deficiency results in dysregulation of lipid efflux pathway in rat kidney

The mechanisms of action of vitamin A deficiency (VAD) on lipid metabolism in the rat kidney were investigated in adult female rats and their offspring. The rats were randomized into three groups: (1) control, in which the mother and offspring received a normal diet (4000 retinol IU/kg diet) for 8 weeks; (2) VAD group, in which the mothers and offspring received a VAD diet (400 retinol IU/kg diet) for 8 weeks; (3) vitamin A-refed group, in which a group of pups on a VAD diet for 8 weeks received a complete diet (6500 retinol IU/kg diet) for 15 days. The lipid metabolism of the offsprings' kidneys and its relation to the expression of apolipoprotein B100 (Apo-B100), liver X receptor alpha (LXR alpha), and retinoid X receptor-alpha/beta (RXR alpha/beta) mRNA was analyzed. VAD was found to alter renal lipid metabolism and its immune environment due to the expression of Apo-B100. Compared with the control, VAD rats had significantly higher levels of transforming growth factor-beta 1 and lower levels of ABCA1, a key gene involved in cholesterol efflux and tissue lipid homeostasis. The expression of LXR alpha and RXR alpha/beta mRNA also decreased in the VAD rat kidney. Vitamin A refeeding reversed all of the changes. Lipid metabolism involved in renal reverse cholesterol transport may be mediated by decreasing the signaling through the ABCA1 cholesterol efflux pathway, which is significantly modified in kidneys of vitamin A-deficient rats.