Microbiota Gut-Brain Axis and Autism Spectrum Disorder: Mechanisms and Therapeutic Perspectives.

This review looks at how gut bacteria might affect autism symptoms. Children with autism often have stomach problems and different gut bacteria compared to other children. The 'gut-brain connection' means gut bacteria can send signals to the brain that might influence behavior. Treatments like probiotics, special diets, and even transplanting healthy gut bacteria from donors have shown some promise in improving both stomach problems and autism behaviors, though more research is needed.

This narrative review examines the microbiota-gut-brain (MGB) axis in autism spectrum disorder, exploring bidirectional communication between gut microbes and the central nervous system. The review synthesizes evidence from recent human, animal, and in vitro studies, focusing on communication pathways, neurodevelopmental implications, and therapeutic interventions. Key mechanisms include neuroanatomical, neuroendocrine, immunological, and metabolic pathways enabling microbes to influence brain development. The review identifies gut dysbiosis patterns in ASD, characterized by reduced microbial diversity and increased pathogenic taxa, associated with intestinal permeability and altered metabolite profiles.

Therapeutic approaches examined include probiotics, prebiotics, fecal microbiota transplantation, antibiotics, and dietary interventions, showing varying degrees of promise for improving gastrointestinal and behavioral symptoms.

The MGB axis represents a potential therapeutic target for ASD interventions. Gut-focused treatments including probiotics, dietary modifications, and microbiota transplants may offer adjunctive benefits for gastrointestinal and behavioral symptoms. However, treatment approaches should be individualized, and families should work with healthcare providers to evaluate appropriateness and safety of interventions.

As a narrative review, this study synthesizes existing research but does not provide new primary data. The authors acknowledge heterogeneity in findings across studies and emphasize the need for rigorous, large-scale studies to clarify causal relationships and evaluate long-term efficacy and safety of interventions.

: Autism Spectrum Disorder (ASD) is a neurodevelopmental condition often accompanied by gastrointestinal (GI) symptoms and gut microbiota imbalances. The microbiota-gut-brain (MGB) axis is a bidirectional communication network linking gut microbes, the GI system, and the central nervous system (CNS). This narrative review explores the role of the MGB axis in ASD pathophysiology, focusing on communication pathways, neurodevelopmental implications, gut microbiota alteration, GI dysfunction, and emerging therapeutics.: A narrative review methodology was employed. We searched major scientific databases including PubMed, Scopus, and Google Scholar for research on MGB axis mechanisms, gut microbiota composition in ASD, dysbiosis, leaky gut, immune activation, GI disorders, and intervention (probiotics, prebiotics, fecal microbiota transplantation (FMT), antibiotics and diet).

Key findings from recent human, animal and in vitro studies were synthesized thematically, emphasizing mechanistic insights and therapeutic outcomes. Original references from the initial manuscript draft were retained and supplemented for comprehensiveness and accuracy.: The MGB axis involves neuroanatomical, neuroendocrine, immunological, and metabolic pathways that enable microbes to influence brain development and function. Individuals with ASD commonly exhibit gut dysbiosis characterized by reduced microbial diversity (notably lowerand) and overpresentation of potentially pathogenic taxa (e.g.,,,). Dysbiosis is associated with increased intestinal permeability ("leaky gut") and newly activated and altered microbial metabolite profiles, such as short-chain fatty acids (SCFAs) and lipopolysaccharides (LPSs).

Functional gastrointestinal disorders (FGIDs) are prevalent in ASD, linking gut-brain axis dysfunction to behavioral severity. Therapeutically, probiotics and prebiotics can restore eubiosis, fortify the gut barrier, and reduce neuroinflammation, showing modest improvements in GI and behavioral symptoms. FMT and Microbiota Transfer Therapy (MTT) have yielded promising results in open label trials, improving GI function and some ASD behaviors. Antibiotic interventions (e.g., vancomycin) have been found to temporarily alleviate ASD symptoms associated withovergrowth, while nutritional strategies (high-fiber, gluten-free, or ketogenic diets) may modulate the microbiome and influence outcomes.: Accumulating evidence implicates the MGB axis in ASD pathogenesis.

Gut microbiota dysbiosis and the related GI pathology may exacerbate neurodevelopmental and behavioral symptoms via immune, endocrine and neural routes. Interventions targeting the gut ecosystem, through diet modification, probiotics, symbiotics, or microbiota transplants, offer therapeutic promise. However, heterogeneity in findings underscores the need for rigorous, large-scale studies to clarify causal relationships and evaluate long-term efficacy and safety. Understanding MGB axis mechanisms in ASD could pave the way for novel adjunctive treatments to improve the quality of life for individuals with ASD.