The role of Akkermansia muciniphila in the regulation of inflammatory bowel disease: intestinal immunity and metabolism

Inflammatory bowel disease (IBD) is closely associated with the abundance of <i>Akkermansia muciniphila</i> (<i>A. muciniphila</i>), a resident member of the intestinal tract that is being developed as a next-generation probiotic. Accumulated evidence has indicated that the live and pasteurized <i>A. muciniphila</i>, as well as its components and secretions, have exhibited protective and ameliorative functions in IBD. Nevertheless, the precise and intricate regulatory mechanisms of <i>A. muciniphila</i> in IBD remain unclear, which is crucial for investigating the etiology of IBD and searching for innovative, targeted therapeutic strategies. In this review, we discuss the reciprocal influence between <i>A. muciniphila</i> and intestinal immunity in IBD, encompassing the roles of immune cells, intestinal epithelial cells (IECs), and intestinal stem cells (ISCs). Subsequently, we outline the mutual regulatory interactions between <i>A. muciniphila</i> and intestinal metabolism, focusing on tryptophan (Trp) metabolism, short-chain fatty acids (SCFAs) metabolism, and bile acids (BAs) metabolism. Understanding how <i>A. muciniphila</i> interacts with its host is a vital step for facilitating its application in IBD therapy.