Tryptophan Metabolism, Regulatory T Cells, and Inflammatory Bowel Disease: A Mini Review

Figure 3

Effects of Trp and its metabolism on the etiology of IBD. Trp deficiency could contribute to the development of IBD, and patients with IBD have lower Trp levels, higher Kyn levels, and elevated IDO expression. Trp: tryptophan; IBD: inflammatory bowel disease; IDO1: indoleamine 2,3-dioxygenase-1; Kyn: kynurenine.