Endoscopic mucosal impedance measurements correlate with eosinophilia and dilation of intercellular spaces in patients with eosinophilic esophagitis

Background & Aims: Penetration of the esophageal epithelium by food antigens is an early event in the pathogenesis of eosinophilic esophagitis (EoE), but the precise relationship among eosinophilia, dilated intercellular spaces (DIS), and decreased barrier function is unclear. We investigated the correlation between site-specific mucosal impedance (MI) measurements of ion flux and esophageal histology, and whether MI measurements can be used to distinguish between patients with active and inactive EoE. Methods: MI was measured (in Ω) in 10 patients with active EoE (>15 eosinophils [eos]/high-power field [HPF]) and in 10 with inactive EoE (<15 eos/HPF, as a result of treatment), and mucosal biopsy specimens were collected from 4 esophageal sites (2, 5, 10, and 15 cm above the Z-line). MI also was measured in 10 individuals without esophageal symptoms (controls). MI measurements, eos/HPF, and DIS grade were compared among patients with EoE and controls. Results: The esophageal MI values were significantly lower in patients with active EoE (1909 Ω) compared with inactive EoE (4349 Ω) or controls (5530 Ω) (P < .001). Biopsy specimens from 4 patients with active EoE contained fewer than 15 eos/HPF and lower-grade DIS than in patients with active disease. There were significant inverse correlations between MI and eos/HPF (rs=-584), as well as between MI and DIS (rs= -531; P < .001). The MI cut-off value of 2300 Ω identified patients with active EoE with 90% sensitivity and 91% specificity, and high-grade DIS with 89% sensitivity and 82% specificity. Conclusions: In patients with EoE, eosinophilia and DIS correlate with MI measurements of ion flux. Endoscopic MI measurement in the esophagus is safe and easy to perform, and can be used to assess activity of diseases such as EoE.