Microbiota in Autism Spectrum Disorder: A Systematic Review

Area of Science:

• Neuroscience
• Microbiology
• Gastroenterology

Background:

• Autism spectrum disorder (ASD) is a neurodevelopmental condition with core symptoms including social interaction and communication difficulties.
• Many children with ASD experience gastrointestinal (GI) disorders, which can significantly impact their quality of life.
• Emerging research suggests a link between gut microbiota dysbiosis and both core ASD symptoms and GI issues.

Approach:

• This review systematically analyzed forty-four studies, including meta-analyses, reviews, and original research, focusing on the gut microbiota composition in children with ASD.
• The analysis examined specific bacterial phyla alterations and the Bacteroidetes to Firmicutes ratio in ASD individuals compared to controls.
• Interventions targeting gut microbiota modulation, such as probiotics, prebiotics, and microbiota transfer therapy (MTT), were assessed for their efficacy.

Key Points:

• ASD children exhibit altered gut microbiota profiles, with trends showing increased Firmicutes and Pseudomonadota and decreased Bacteroidetes.
• A lower Bacteroidetes to Firmicutes ratio in ASD is associated with behavioral and GI abnormalities.
• Probiotic interventions using Lactobacillus, Bifidobacterium, and Streptococcus strains demonstrated potential in alleviating ASD-related behavioral and GI symptoms.

Conclusions:

• The gut microbiota plays a significant role in the gut-brain axis, influencing both core ASD symptoms and associated GI disorders.
• Microbiota transfer therapy (MTT) shows promise for lasting benefits, while prebiotics require further investigation for conclusive efficacy.
• Standardized, comprehensive research is crucial to overcome study heterogeneity and methodological variations, paving the way for effective gut-targeted therapies for ASD.