Since claudin-8 acts as sealing claudins in junctional regions of normal epithelial surface as well as crypts(91) and prevents paracellular back-leakage of Na+ in colonic reabsorption(115), its reduction and redistribution from TJs to cytoplasm may lead to TJ structure disruption and increased epithelial permeability in IBD, especially in active CD. Here, CLDN8 is linked to irritable bowel syndrome.