A beautiful mind: The role of gut microbes and their therapeutic potential in autism spectrum disorder

Autism Spectrum Disorder (ASD) is a complex neurodevelopmental condition that affects about 1 in 100 children worldwide. It involves a wide range of challenges, from social difficulties to repetitive behaviours, often accompanied by other conditions like epilepsy, sleep problems, and digestive issues. Despite ongoing research, we still don’t fully understand what causes these disorders or how to effectively diagnose and treat ASD. Recent studies suggest that the gut microbiota, the community of microbes living in our intestine, may play a significant role in neurodevelopmental disorders like ASD. The gut and brain can communicate in a bidirectional manner through a complex network called the gut-brain axis, which involves immune, metabolic, and neuronal pathways. Alterations in the composition of the gut microbes, known as dysbiosis, could contribute to ASD development and severity by disrupting these connections. This thesis investigates the gut microbiome’s role in ASD from multiple angles. We identified specific gut bacterial markers linked to the condition in three independent study populations using machine learning. We developed different humanized mouse models that are promising tools to deepen on the investigation of the gut-brain axis in ASD. Finally, we also explored dietary interventions, such as probiotic and synbiotic diets, to promote ‘healthy’ changes in the gut bacterial composition that might translate into beneficial effects in processes along the gut-brain axis like behaviour. By deepening our understanding of how gut microbes interact with the brain, this research offers new hope for more effective and personalized treatments for ASD. It highlights the potential of targeting the gut microbiome to improve the quality of life for individuals living with this condition.