Tryptophan metabolism and interactions with gut microbiota

The intestine is the first tine of defense against harmful pathogens. Altered intestinat homeostasis is associated with increased intestinal permeability and the development of many diseases, including cardiometabolic diseases. Among the metabolites that play an important role in intestinal homeostasis, L Tryptophan (Trp) is one of the essential amino acids supplied by the diet. Its metabolism plays a key role in the modulation of gut microbiota, with major impacts locally on the intestine and in the periphery on the development of inflammatory diseases. Recently, new data have shown that the catabolism of Trp by the host-expressed enzyme indoleamine 2, 3-dioxygenase 1 (IDO1) affects the metabolism of Trp, particularly that which depends on the gut microbiota responsible for the generation of indole metabolites. This review summarizes the recent advances concerning the role of the different actors involved in the catabolism of Trp as well as the dialogue between the host and the intestinal microbiota. (C) 2021 Societe francaise de nutrition. Published by Elsevier Masson SAS. All rights reserved.