Bacteroides is increased in an autism cohort and induces autism-relevant behavioral changes in mice in a sex-dependent manner.

Autism Spectrum Disorder (ASD) is a neurodevelopmental condition which is defined by decreased social communication and the presence of repetitive or stereotypic behaviors. Recent evidence has suggested that the gut-brain axis may be important in neurodevelopment in general and may play a role in ASD in particular. Here, we present a study of the gut microbiome in 96 individuals diagnosed with ASD in Israel, compared to 42 neurotypical individuals. We determined differences in alpha and beta diversity in the microbiome of individuals with ASD and demonstrated that the phylum Bacteroidetes and genus Bacteroides were the most significantly over-represented in individuals with ASD. To understand the possible functional significance of these changes, we treated newborn mice with Bacteroides fragilis at birth. B. fragilis-treated male mice displayed social behavior dysfunction, increased repetitive behaviors, and gene expression dysregulation in the prefrontal cortex, while female mice did not display behavioral deficits. These findings suggest that overabundance of Bacteroides, particularly in early life, may have functional consequences for individuals with ASD.

Unique Trans-fatty Acid Profile in Children With Attention Deficit Hyperactivity Disorder.

Background: Attention deficit hyperactivity disorder (ADHD) is the most common developmental disorder in children. Studies suggest an association between fatty acids composition and ADHD pathogenesis. We aimed to investigate whether children diagnosed with ADHD present unique fatty acid profiles in red blood cells (RBC), as compared to children without ADHD. Method: We examined 60 children aged 6-14 years, out of which 32 were diagnosed with ADHD, and 28 were not. Blood was collected from all children to quantify an array of 26 fatty acids from RBC membranes. Fatty acid methyl esters were generated by acid transesterification and analyzed by gas chromatography. Results: We found that children with ADHD presented unique fatty acid profiles on RBC membranes with significantly higher levels of most of the trans-fatty acids (Total trans-fatty acids 0.64 ± 0.21 vs. 0.49 ± 0.18 p = 0.003) and lower levels of docosahexaenoic acid (DHA), as compared to controls (4.06 ± 0.79 vs. 4.68 ± 1.37 p = 0.040). Additionally, total trans-fatty acids were higher in children with extremely severe clinical ADHD condition score, as compared to milder ADHD scores and to control children (0.72 ± 0.18, 0.64 ± 0.20, 0.61 ± 0.22, 0.49 ± 0.18, p = 0.010, accordingly). Conclusion: Children with ADHD have higher levels of trans-fatty acids in RBCs, compared to children without ADHD. This study points to a possible link between trans-fatty acids and ADHD. Understanding these findings and the clinical meaning will potentially contribute to a more targeted dietary intervention.