Investigating the Effects of Probiotic Supplementation on the Gut-Brain Axis in Autism Spectrum Disorder

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Historically, the purpose of probiotic use in autism spectrum disorder (ASD) has been associated with alleviating co-morbid gastrointestinal symptoms. Recent studies have shown promise for the use of probiotics in modulating brain function to improve the behavioural symptoms of ASD through the microbiota-gut-brain axis. In the present study, we assessed the impact of two probiotic strains in mitigating autism-related symptomology in the BTBR T+ Itpr3tf/J mouse model of autism spectrum disorder (ASD). Male juvenile BTBR mice were randomized into 1) control, 2) Lr probiotic (1 x 109 CFU/mL Lacticaseibacillus rhamnosus HA-114), and 3) Ls probiotic groups (1 x 109 CFU/mL Ligilactobacillus salivarius HA-118) (n=18-21/group), receiving treatments in drinking water for 4-weeks. Gut microbiota profiling by 16S rRNA showed Lr, but not Ls supplementation, to increase microbial richness and phylogenetic diversity, with a rise in potential anti-inflammatory and butyrate-producing taxa. Assessing serum and brain metabolites, Lr and Ls supplementation produced distinct metabolic profiles, with Lr treatment elevating concentrations of potentially beneficial neuroactive compounds, such as 5-aminovaleric acid and choline. As mitochondrial dysfunction is often observed in ASD, we assessed mitochondrial oxygen consumption rates in the prefrontal cortex and hippocampus. No differences were observed for either treatment. Both Lr and Ls treatment reduced behavioural deficits in social novelty preference. However, no changes in hyperactivity, repetitive behaviour, and sociability were observed. Results show Lr to impart positive changes along the microbiota-gut-brain axis, exhibiting beneficial effects on selected behaviour, gut microbial diversity, and metabolism in BTBR mice.
Gut Microbiota, Autism, Behaviour, Probiotics, Metabolomics, Mitochondria, Gut-Brain Axis
Pochakom, A. (2022). Investigating the effects of probiotic supplementation on the gut-brain axis in autism spectrum disorder (Master's thesis, University of Calgary, Calgary, Canada). Retrieved from