Altered Gut Microbiota in Korean Children with Autism Spectrum Disorders

Abstract

Autism spectrum disorder (ASD) is a neurodevelopmental disorder characterized by social and behavioral impairments. Recent studies have suggested that gut microbiota play a critical role in ASD pathogenesis. Herein, we investigated the fecal microflora of Korean ASD children to determine gut microbiota profiles associated with ASD. Specifically, fecal samples were obtained from 54 children with ASD and 38 age-matched children exhibiting typical development. Systematic bioinformatic analysis revealed that the composition of gut microbiota differed between ASD and typically developing children (TDC). Moreover, the total amounts of short-chain fatty acids, metabolites produced by bacteria, were increased in ASD children. At the phylum level, we found a significant decrease in the relative Bacteroidetes abundance of the ASD group, whereas Actinobacteria abundance was significantly increased. Furthermore, we found significantly lower Bacteroides levels and higher Bifidobacterium levels in the ASD group than in the TDC group at the genus level. Functional analysis of the microbiota in ASD children predicted that several pathways, including genetic information processing and amino acid metabolism, can be associated with ASD pathogenesis. Although more research is needed to determine whether the differences between ASD and TDC are actually related to ASD pathogenesis, these results provide further evidence of altered gut microbiota in children with ASD, possibly providing new perspectives on the diagnosis and therapeutic approaches for ASD patients.

Gut microbiota profiles in mental disorders and their association with behavior in children and adolescents.

“…However, consistent results were not obtained. Five studies revealed a decreased Bacteroidetes/Firmicutes ratio in ASD [31,39,44,49,55]. Contradictory ndings were reported by the same number of authors [34,36,38,47,48], and in three other studies, no signi cant changes were observed [29,35,37].…”

“…Lower total SCFAs in stool samples of children with autism were reported in two studies [40,53], while higher levels were reported in another one [49]. Further, lower fecal acetate and butyrate [28,53] and lower propionate in autistic patients were described [53].…”

“…Lower alpha diversity in ASD patients was described in seven studies [26][27][28][29][30][31][32], while in nine cases, higher alpha diversity was found [33][34][35][36][37][38][39][40][41]. Another nine studies did not reveal any signi cant differences in alpha diversity between ASD patients and healthy controls [42][43][44][45][46][47][48][49][50]. In the rest of studies, information about alpha diversity changes was not provided [51][52][53][54][55][56].…”

“…In the rest of studies, information about alpha diversity changes was not provided [51][52][53][54][55][56]. Differences in beta diversity were described in ten studies [26,28,29,32,36,37,39,44,47,49].…”

“…Authors suggested that elevated propionate in ASD patients might be explained also by its reduced degradation as a consequence of E. coli drop, in addition to the enhanced production by Clostridia [27]. However, no signi cant differences in the levels of acetate, propionate, and butyrate and no differences in relative concentrations of SCFAs were also described [26,49]. Although many studies suggest the possible role of SCFA in ASD manifestations, more research is required to prove it.…”