NR1I2 and Crohn ileitis: Considering the fact that Shakhnovich et al. have reported a downregulated expression of PXR in sites of active inflammation in CD, potentially indicating a modulation of PXR expression by inflammation [47], we could assume that the downregulation of these receptors in the UC ileum could be the result of inflammation, developing due to the regurgitation of colonic content into the ileum (backwash ileitis) [48].