Disentangling the relationship of gut microbiota, functional gastrointestinal disorders and autism: a case–control study on prepubertal Chinese boys

Abstract

Emerging evidence of an altered gut microbiome in autism spectrum disorder (ASD) suggests a pathomechanism through the gut–brain axis despite the inconsistent microbiome profile reported across studies. One of the knowledge gaps in the existing ASD microbiota studies is the lack of systematic exploration of the role of comorbid functional gastrointestinal disorder (FGID) in the association of ASD and altered gut microbiome. Consequently, 92 ASD and 112 age-matched typically developing (TD) boys were profiled on general psychopathology, FGID status by Rome IV classification, and gut microbiota using 16S ribosomal RNA amplicon sequencing at the V4 hypervariable region. Compared to TD, a significant decrease in the within-sample abundance of taxa was observed in ASD, regardless of FGID status. The microbiota of ASD FGID+ and ASD FGID− clustered apart from the TD groups. The microbiota of ASD FGID+ also showed qualitative differences from that of ASD FGID− and had the highest-level Firmicutes: Bacteroidetes ratio, which was paralleled by elevated levels of anxiety and overall psychopathology. The altered gastrointestinal microbiota composition in ASD appeared to be independent of comorbid FGID. Further studies should address how FGID may mediate neuropsychiatric symptoms in ASD through inflammation along the microbiota–gut–brain axis.

Characteristics of gut microbiota of term small gestational age infants within 1 week and their relationship with neurodevelopment at 6 months

“…Gut microbiota affects various normal psychological processes and phenomena, participating in the pathophysiology of several psychological and neurological diseases ( Liang et al, 2018 ). It has been reported that the gut microbial composition is altered in children with autism ( Finegold et al, 2010 ; Plaza-Díaz et al, 2019 ; Dan et al, 2020 ; Saurman et al, 2020 ; Wong et al, 2022 ) and adults with Parkinson’s disease ( Vascellari et al, 2020 ; Hirayama and Ohno, 2021 ) and Alzheimer’s disease ( Zhuang et al, 2018 ; Bostanciklioğlu, 2019 ). Many studies have shown that probiotics are effective against anxiety, depression, autism spectrum disorder (ASD), and obsessive-compulsive disorder, and can also improve cognitive function, learning, and memory ability ( Wang et al, 2016 ; Eastwood et al, 2021 ; Kim et al, 2021 ; Alemohammad et al, 2022 ).…”

Gut Microbiota Profiles in Children and Adolescents with Psychiatric Disorders

“…Several researchers suggest that differences in microbial diversity between ADS patients and healthy controls may be associated with autistic symptoms, but the results from forty-one reviewed studies were not consistent. Lower alpha diversity (microbial diversity within the same group’s samples) in ASD patients was described in ten studies [ 25 , 26 , 27 , 28 , 29 , 30 , 31 , 32 , 33 , 34 ], while in thirteen cases, higher alpha diversity was found [ 19 , 35 , 36 , 37 , 38 , 39 , 40 , 41 , 42 , 43 , 44 , 45 , 46 ]. Another eleven studies did not reveal any significant differences in alpha diversity between ASD patients and healthy controls [ 47 , 48 , 49 , 50 , 51 , 52 , 53 , 54 , 55 , 56 , 57 ].…”

“…In the rest of the studies, information about alpha diversity differences were not provided [ 58 , 59 , 60 , 61 , 62 , 63 , 64 ]. Differences in beta diversity (community diversity between different group’s samples) were reported in fifteen studies [ 19 , 25 , 27 , 28 , 31 , 33 , 34 , 38 , 39 , 41 , 44 , 45 , 49 , 52 , 54 ].…”

“…However, consistent results were not obtained. Six studies revealed a decreased Bacteroidetes/Firmicutes ratio in ASD [ 30 , 34 , 41 , 49 , 54 , 62 ]. Contradictory findings were reported by the same number of authors [ 36 , 38 , 40 , 52 , 53 , 57 ], and in four other studies, no significant differences were observed [ 28 , 37 , 39 , 64 ].…”

“…Interestingly, in the same study, other bacteria were found to be characteristic of the gut microbiota in children with ASD compared to controls [ 65 ]. In the recently published study of Wong et al (2022), the abundances of genera Fusicatenibacter , Dialister , and Phasolarctobacterium were different in the ASD group with GI symptoms when compared with ASD, as well as healthy participants, both without GI symptoms [ 34 ]. Moreover, in the last-mentioned study, enriched Turicibacter was observed in the ASD group with GI symptoms.…”