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Updated: Oct 16, 2025

Functional Assessment of Intestinal Tight Junction Barrier and Ion Permeability in Native Tissue by Ussing Chamber Technique
Published on: May 26, 2021
Association of the Tight Junction Protein Claudin-4 with Lung Function and Exacerbations in Chronic Obstructive
Shinhee Park1, Pureun-Haneul Lee2, Ae Rin Baek1
1Division of Allergy and Respiratory Medicine, Department of Internal Medicine, Soonchunhyang University Bucheon Hospital, Bucheon, Republic of Korea.
Purpose:
Chronic obstructive pulmonary disease (COPD) imposes a major healthcare burden. A tight junction protein, claudin-4 (CLDN4), may play a protective role in acute lung injury, but its role in COPD is unclear. To investigate the relationship between CLDN4 and COPD, we evaluated the association of CLDN4 with the clinical parameters of COPD, including exacerbations.
Patients And Methods:
We analyzed a cohort of 30 patients with COPD and 25 healthy controls and evaluated their clinical parameters, including lung function. The plasma CLDN4 level in stable and exacerbated COPD was measured.
Results:
The COPD patients were all males and predominantly smokers; their initial lung function was poorer than the healthy controls. The mean CLDN4 plasma level was 0.0219 ± 0.0205 ng/mg in the control group, 0.0086 ± 0.0158 ng/mg in the stable COPD group (COPD-ST) and 0.0917 ± 0.0871 ng/mg in the exacerbated COPD (COPD-EXA) group. The plasma CLDN4 level was significantly lower in the COPD-ST than the control group, but was significantly elevated in the COPD-EXA group. The plasma CLDN4 level was inversely correlated with forced vital capacity and forced expiratory volume in 1 second in the COPD-EXA group (r=0.506, P=0.001 and r=0.527, P<0.001, respectively).
Conclusion:
The plasma CLDN4 level is closely correlated with COPD exacerbations and decreased lung function. This suggests that CLDN4 has potential as a severity marker for COPD.
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