Tight junctions in inflammatory bowel diseases and inflammatory bowel disease associated colorectal cancer

Abstract

Inflammatory bowel diseases are characterised by inflammation that compromises the integrity of the epithelial barrier. The intestinal epithelium is not only a static barrier but has evolved complex mechanisms to control and regulate bacterial interactions with the mucosal surface. Apical tight junction proteins are critical in the maintenance of epithelial barrier function and control of paracellular permeability. The characterisation of alterations in tight junction proteins as key players in epithelial barrier function in inflammatory bowel diseases is rapidly enhancing our understanding of critical mechanisms in disease pathogenesis as well as novel therapeutic opportunities. Here we give an overview of recent literature focusing on the role of tight junction proteins, in particular claudins, in inflammatory bowel diseases and inflammatory bowel disease associated colorectal cancer.

Keywords: Claudin; Crohn’s disease; Pouchitis; Tight junction; Ulcerative colitis.

Figure 1

Electron microscopy of pouch epithelium tight junction complex in non-inflamed pouch (A) and electron micrograph demonstrating dendritic cell penetrating between two epithelial cells in pouchitis (B). Bar = 0.1 μm. Solid arrow: Dendritic cell; Dashed arrow: Tight junction complex between epithelial cell and dendritic cell.