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Updated: Jun 22, 2026

An Intravital Microscopy-Based Approach to Assess Intestinal Permeability and Epithelial Cell Shedding Performance
Published on: December 3, 2020
Urine-based detection of intestinal tight junction loss
Geertje Thuijls1, Joep P M Derikx, Jacco-Juri de Haan
1Department of Surgery, Maastricht University Medical Centre and Nutrition and Toxicology Research Institute Maastricht, The Netherlands.
Background:
Tight junction breakdown, with loss of the important sealing protein claudin-3, is an early event in the development of intestinal damage. Therefore, noninvasive analysis of intestinal tight junction status could be helpful in early detection of intestinal injury.
Aim:
To investigate the usefulness of urinary claudin-3 as marker for intestinal tight junction loss.
Methods:
A rat hemorrhagic shock model and a human setting of known intestinal damage, that is, patients with relapsed inflammatory bowel disease (IBD), were used to investigate intestinal tight junction status by immunohistochemical staining and urinary claudin-3 levels by western blot.
Results:
In rats claudin-3 urine levels increased rapidly after histologically proven intestinal tight junction loss, with significantly elevated levels at 90 minutes after shock compared with sham-operated animals [mean+/-SEM: 611+/-101 intensity (INT), n=6 vs. 232+/-30 INT, n=6; P<0.05]. Moreover, in colonic biopsies of patients with IBD relapse claudin-3 staining was reduced compared with biopsies of patients with IBD without signs of disease. Concomitantly, significantly increased claudin-3 urine levels were found in these patients (502+/-67 INT, n=10) compared with patients with IBD in remission (219+/-17 INT, n=10, P<0.001) and healthy volunteers (225+/-38 INT, n=10, P<0.001).
Conclusion:
Here we show for the first time in both an experimental and clinical setting a strong relation between intestinal tight junction loss and urinary claudin-3 levels. These findings suggest that measurement of urinary claudin-3 can be used as noninvasive marker for intestinal tight junction loss. This offers new opportunities for early diagnosis and follow-up of intestinal injury.

