Narrative Review: The Effect of Vitamin A Deficiency on Gut Microbiota and Their Link with Autism Spectrum Disorder.

Autism spectrum disorder (ASD) is a group of neurodevelopmental disorders defined by a lack of social behaviors, repetitive behaviors and nonverbal interactions, such as limited eye contact, facial expression, and body gesturing. It is not a single condition, but rather a multi-factorial disorder caused by hereditary and non-genetic risk factors, as well as their interaction. According to several studies, the gut microbiota may have a role in the pathophysiology of autism spectrum disorder.

Expression of retinoic acid receptors and retinoid X receptors in normal and vitamin A deficient adult rat brain.

The importance of retinoic acid and retinoid X receptors (RARs and RXRs) in the metabolism and functioning of the nervous tissue is well documented, but few data are available about the differences on their distribution in males and females, as well as about the possible changes in a vitamin A deficient state (VAD). Therefore, the aim of this study has been to use immunohistochemistry to determine the cellular localization of RARs (α, β, γ) and RXR (α, β, γ) in brain areas in the normal and vitamin A deficient rat, in both males and females. RARα and β isotypes were detected in practically all the male brain areas whereas immunostaining was weak or absent in the female brain except RARα.

Effect of vitamin A deficiency on retinol and retinyl esters contents in rat brain.

In the present study, the pattern of vitamin A (retinol and retinyl esters) contents in discrete brain areas was investigated in Wistar rats (both sexes of 10-12 weeks old) fed on vitamin A deficient diet. The animals were placed on standard laboratory diet for the control animals and a vitamin A deficient diet for the experimental animals for 20 weeks. At the end of this period, brain retinol and retinyl esters contents from control and vitamin A deficient diet animals were measured by HPLC.