The essential amino acid tryptophan (trp), as a precursor of numerous molecules acting at the interface between host and microbiota, is fundamental in the modulation of the gut-brain axis. In the intestine, trp undergoes 3 main metabolic pathways: kynurenine, 5-HT and AhR ligand (aryl hydrocarbon receptor, from which it can be activated or deactivated also by indole derivatives such as kynurenine). Pathways that can be controlled directly or indirectly by the microbiota. This review therefore attempts to understand the main aspects of the role of trp metabolites in the regulation of host-microbiota crosstalk in health and disease with particular attention to irritable bowel syndrome (IBS) and inflammatory bowel disease (IBD), both characterized by psychiatric disorders. It is demonstrated here that trp metabolites have a central role in the regulation of the gut-brain axis in both physiological and pathological conditions.
Year: 2020
Nationality: Italy
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