CLDN2 and inflammatory bowel disease: For this purpose, we aimed to evaluate blood inflammatory parameters, such as IL-6, IL-10, IL-17, IL-22, and TNF-α, and intestinal mRNA expression of iNOS, PPAR-γ, hypoxia-inducible factor (HIF-1α), zonula occludens-1 (ZO-1), claudin-2, occludin, and succinate receptor 1 (SUCNR1) in IBD patients depending on disease activity.