Table 1.
Expression modulations of claudins in the pathogenesis of IBD.
| Claudins | Localization | Role in IBD | CD | UC |
|---|---|---|---|---|
| Claudin 1 | Crypt epithelia | Intestinal barrier permeability | High | High |
| Claudin 2 | Surface colonocytes | Paracellular permeability | High | High |
| Claudin 3 | Crypt epithelia | Intestinal barrier development | Low | Low |
| Claudin 4 | Crypt epithelia | Physiological chloride reabsorption | Low | Low |
| Claudin 5 | Crypt epithelia | Intestinal barrier permeability | Low | ND |
| Claudin 7 | Surface colonocytes | Paracellular flux of small organic solutes | ND | Low |
| Claudin 8 | Crypt epithelia | Na+ reabsorption | Low | ND |
| Claudin 12 | Colonic epithelia | Ca2+ permeability in enterocytes | Low | ND |
| Claudin 15 | Colonic epithelia | Na+ permeability | ND | ND |
| Claudin 18 | Colonic epithelia | Paracellular H+ efflux | ND | High |
High, high expression; Low, low expression; ND, not detected.