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

Autism Spectrum Disorder is a complex neurodevelopmental condition that affects about one in hundred 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 do not fully understand what causes these disorders or how to effectively diagnose and treat autism.

Recent studies suggest that the gut microbiota, the community of microbes living in our intestines, may play a significant role in autism. 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 autism development and severity by disrupting these connections.

This thesis investigates the role of gut microbiome in autism from multiple angles. We identified specific gut bacterial markers linked to the condition in three independent study populations using machine learning. We developed new humanized mouse models by transplanting human intestinal microbes into mice. These models are promising tools to deepen on the investigation of the gut-brain axis in autism. Finally, we explored dietary interventions as well, 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 autism. It highlights the potential of targeting the gut microbiome to improve the quality of life for individuals living with this condition.