Immune-related mechanisms of fecal microbiota transplantation in the intestinal microenvironment as a potential intervention for autism spectrum disorder patients.

内容摘要

Autism spectrum disorder (ASD) is a complex neurodevelopmental condition characterized by behavioral, cognitive, and motor impairments. There is increasing evidence linking ASD with an altered composition of the gut microbiota and chronic low-grade inflammation, suggesting a key role of the gut-brain axis (GBA) in the pathophysiological development of this condition. This mini review explores the molecular and immunological mechanisms underlying the associations between ASD and gut dysbiosis, with particular emphasis on the therapeutic potential of fecal microbiota transplantation (FMT). Dysbiosis can compromise the integrity of the intestinal barrier, increasing permeability and the translocation of pathogen-associated molecular patterns (PAMPs), such as lipopolysaccharides (LPS), thereby releasing inflammatory cytokines, including IL-6 and TNF-α. These mediators activate the mucosal immune pathways, such as the NF-κB signaling and NLRP3 inflammasome, thereby contributing to neuroinflammation and elevating intestinal biomarker levels, such as S100B, RANTES, and calprotectin. Emerging evidence suggests that FMT may restore microbial diversity, promote the expansion of beneficial short-chain-fatty-acid-producing taxa, and reinforce intestinal tight junction proteins, thereby improving the integrity of the gut barrier. These effects may attenuate systemic inflammation, modulate central immune responses, regulate neurotransmitter levels, and improve gastrointestinal and behavioral outcomes in individuals with ASD. Despite these promising findings, current evidence remains limited by small sample sizes, methodological heterogeneity, and short follow-up periods. Hence, future research efforts should prioritize well-designed randomized controlled trials and the development of personalized microbial-based interventions to establish FMT as a safe and effective therapeutic strategy for ASD.