Figure 18.

Levels of the microbiota-derived metabolite IPA are decreased in fecal samples from patients with Crohn’s disease (CD) and ulcerative colitis (UC). (A) Analysis of fecal metabolomic profiles from non-IBD, CD, and UC patients as part of the Human Microbiome Project 2 (HMP2) deposited on the NIH Metabolomics Workbench under the Project ID PR000639 (n = 135 non-IBD, n = 265 CD, n = 146 UC; IAA, indole-3-acetic acid; IPA, indole-3-propionic acid). Expression of inflammatory genes in human CCD-18Co cells pretreated with IPA (100 mmol/L) for 24 hours before adding (B) LPS or (C) cytomix (human recombinant TNF-α, Il-1β, and IFN-γ) for 12 hours (n = 3 per group). Data are presented as mean ± standard error of the mean. One-way analysis of variance with Tukey post hoc test. ^∗P < .05, ^∗∗P < .01, ^∗∗∗P < .001.