Recent studies showed a strong relationship between intestinal tight junction loss and urinary claudin-3 levels in both a rat hemorrhagic shock model and in patients suffering from IBD or necrotizing enterocolitis, or undergoing major surgery, thereby suggesting that measurement of urinary claudin-3 can be used to some extent as non-invasive marker for intestinal tight junction loss [17]. Here, CLDN3 is linked to irritable bowel syndrome.