Differences in Mucosal Permeability Among Patients With Ulcerative Colitis Classified Based on the Colonic Location and Disease Activity

Factors affecting mucosal permeability (MP) in ulcerative colitis (UC) are largely unknown. We aimed to investigate the difference in MP among patients with UC classified according to the colonic locations and to evaluate the correlations between local MP and endoscopic or histological activity of UC. The transepithelial electrical resistance (TER), which is inversely proportional to permeability, of tissue samples from the mucosa of the ascending colon, descending colon, and rectum of patients with UC and healthy individuals (HIs) was measured by using the Ussing chamber. TERs were compared between patients with UC and HIs and evaluated according to colonic locations and disease activity of UC. Thirty-eight patients with UC and 12 HIs were included in this study. Both in HIs and patients with UC, MP tends to be higher in the anal side. TER in the ascending colon was significantly lower in patients with UC than in HIs (45.3 ± 9.0 Ω × cm 2 vs 53.5 ± 9.7 Ω × cm 2 , P = 0.01). The increased permeability in UC was observed also in the descending colon, only when the inflammation involved the location. A significant correlation between TER and endoscopic activity was found in the rectum only ( r = -0.49, P = 0.002). There were no significant correlations between TERs and UC histology. The MP in the colon differs according to the colonic location. The ascending colon among patients with UC showed disease-specific changes in MP, whereas the MP is increased in proportion to the endoscopic activity in the rectum.