Dose-Dependent Beneficial Effects of Tryptophan and Its Derived Metabolites on Akkermansia In Vitro: A Preliminary Prospective Study

Akkermansia muciniphila, a potential probiotic, has been proven to lessen the effects of several diseases. As established, the relative abundance ofAkkermansiais positively correlated with tryptophan metabolism. However, the reciprocal interaction between tryptophan andAkkemansiais still unclear. Herein, for the first time, the possible effects of tryptophan and its derived metabolites onA. muciniphilawere preliminarily investigated, including growth, physiological function, and metabolism. Obtained results suggested that 0.4 g/L of tryptophan treatment could significantly promote the growth ofA. muciniphila. Notably, when grown in BHI with 0.8 g/L of tryptophan, the hydrophobicity and adhesion ofA. muciniphilawere significantly improved, potentially due to the increase in the rate of cell division. Furthermore,A. muciniphilametabolized tryptophan to indole, indole-3-acetic acid, indole-3-carboxaldehyde, and indole-3-lactic acid. Indoles produced by gut microbiota could significantly promote the growth ofA. muciniphila. These results could provide a valuable reference for future research on the relationship between tryptophan metabolism andA. muciniphila.Keywords:Akkermansia;tryptophan metabolites;indole;indole derivates