Intestinal Barrier Dysfunction and Microbiota–Gut–Brain Axis: Possible Implications in the Pathogenesis and Treatment of Autism Spectrum Disorder

Abstract

Autism spectrum disorder (ASD) is a complex neurodevelopmental disorder with multifactorial etiology, characterized by impairment in two main functional areas: (1) communication and social interactions, and (2) skills, interests and activities. ASD patients often suffer from gastrointestinal symptoms associated with dysbiotic states and a “leaky gut.” A key role in the pathogenesis of ASD has been attributed to the gut microbiota, as it influences central nervous system development and neuropsychological and gastrointestinal homeostasis through the microbiota–gut–brain axis. A state of dysbiosis with a reduction in the Bacteroidetes/Firmicutes ratio and Bacteroidetes level and other imbalances is common in ASD. In recent decades, many authors have tried to study and identify the microbial signature of ASD through in vivo and ex vivo studies. In this regard, the advent of metabolomics has also been of great help. Based on these data, several therapeutic strategies, primarily the use of probiotics, are investigated to improve the symptoms of ASD through the modulation of the microbiota. However, although the results are promising, the heterogeneity of the studies precludes concrete evidence. The aim of this review is to explore the role of intestinal barrier dysfunction, the gut–brain axis and microbiota alterations in ASD and the possible role of probiotic supplementation in these patients.

Seeing beyond words: Visualizing autism spectrum disorder biomarker insights

“…Consequently, disruptions in the gut microbiota could lead to disturbances in neurotransmitter levels, potentially triggering or exacerbating E/I imbalances in individuals with ASD, thereby affecting behavior and emotions. This underscores the vital role of the gut microbiota and neurotransmitters in the pathogenesis of ASD [ 168 ].…”

Probiotics: Bridging the interplay of a healthy gut and psychoneurological well‐being

“…Research has demonstrated that the ingestion of a probiotic blend (10 10 CFU/day) comprising L. rhamnosus, B. bifidum, L. plantarum LP28, B. longum, Lactobacillus rhamnosis GG, L. lactis over 16 weeks effectively shields dopamine-releasing neurons and consequently mitigates the decline in motor dysfunctions in MitoPark PD mice. A study was conducted to investigate the impact of probiotic Lacticaseibacillus paracasei on motor disorders in rats with PD (Dargenio et al, 2023). The results revealed that the group receiving probiotic L. paracasei exhibited reduced apomorphine rotation test scores compared to the group receiving saline.…”

Exposure to Environmental Pesticides and the Risk of Autism Spectrum Disorders: A Population-Based Case-Control Study

“…Recently, there has been a growing emphasis on investigating the link between autism and the gut–brain axis (GBA). The GBA is a bidirectional communication system between the intestine and the brain, where the intestinal microbiota consisting of bacteria, viruses, archaea, yeasts, and protists in the mucosa plays a crucial role [ 35 ]. In this regard, a significant incidence of gastrointestinal disorders has been identified among children with ASD compared to children with typical development [ 36 ].…”