Microbiota-gut-brain axis: towards a microbiota-centred approach for irritable bowel syndrome

Irritable Bowel Syndrome (IBS) is a highly prevalent Disorder of the Gut-Brain Interaction (DGBI). Despite years of research, the mechanisms of IBS pathogenesis are not yet fully understood, but a key role is played by the gut-brain axis, whose alteration may lead to visceral hypersensitivity and altered motility. In recent years, advancements in research on the gut microbiota have shifted the understanding of the underlying pathophysiological mechanisms in IBS, with increasing attention to the role of the microbiota. In IBS patients, studies showed an altered gut microbial composition, with elevated levels of Clostridia and Escherichia coli, while Bacteroidia, Lactobacillus spp., and Bifidobacterium spp. were diminished. Moreover, an increased Firmicutes/ Bacteroidetes ratio and a lower microbial diversity was commonly observed in many IBS patients. The complex interplay between the gut microbiota and the gut-brain axis is leading to the intriguing concept of a microbiota-gut-brain axis. Evidence for microbiota- altering interventions is still heterogeneous, with a described role of antibiotics, probiotics, prebiotics, while interventions such as Faecal Microbiota Transplantation (FMT) remain used primarily in research settings. A knowledge gap still exists about the microbiota profile of the ideal donor in FMT for IBS patients. Finally, the recent advancements in artificial intelligence offer new possibilities to improve diagnosis of IBS and efficacy of microbiota altering interventions to improve symptoms. Today, there is a need for gastroenterologists to develop expertise in this field and to collaborate with specialist of microbiota to manage this complex disease. Microbiota tests are increasingly used by patients, and personalized medicine will require gastroenterologists to adopt microbiota modulation strategies with the help of an expert microbiologist.

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