Organisé par le département d’Etudes cognitives
The emerging science of brain gut microbiome communication
Par Emeran Mayer (UCLA)
Preclinical studies published during the past decade have clearly established an important role of the gut microbiota in behavior and in the modulation of key components of the gut brain axis, including brain structure and function. However, there is limited evidence from studies in human subjects to demonstrate a causative role of gut microbiota brain interactions in health and disease. Our group has published the first evidence that perturbation of the gut microbiome in healthy individuals can lead to altered brain responses to emotional stimuli. This effect was likely mediated by alterations in gut microbial metabolites, as no effect of the probiotic intervention on gut microbial composition was observed. A number of clinical studies have identified associations of altered gut microbial composition with clinical symptoms of patients with major depressive disorder, Parkinson’s disease, hepatic encephalopathy, and autism spectrum disorders. Fecal microbial transfer from some of these patients alters emotional behavior in rodents. Associations of gut microbial composition and metabolites with brain parameters have also been shown in patients with irritable bowel syndrome and in healthy subjects. We have been using multimodal brain imaging of healthy human subjects and disease populations (irritable bowel syndrome, obesity) to identify correlations between a multitude of structural and functional brain parameters with gut microbial composition and microbial metabolites. Early results demonstrate cross sectional correlations between gut microbial composition and grey and white matter changes primarily within sensory processing regions of the brain. In ongoing studies, we are looking at the involvement of gut microbiota and their metabolites in brain changes in mediating the therapeutic effects of bariatric surgery in obesity, and of mind based therapies (cognitive behavioral therapy, mindfulness based stress reduction) in chronic visceral pain.