FFAR4 and inflammatory bowel disease: Furthermore, the free fatty acid-sensing receptors FFAR2, FFAR4, and GPR84 were also found to be upregulated in IBD, with FFAR2 exhibiting upregulated expression in the inflamed UC colon, FFAR4 in the inflamed CD ileum and in UC, and GPR84 in the inflamed CD ileum and colon.