Bioimpedance spectroscopy: a new tool to assess early esophageal changes linked to gastroesophageal reflux disease?

Abstract

Bioimpedance spectroscopy can identify pathological changes related to precancerous lesions of the cervix uteri and esophagus. It therefore has the potential to detect early reflux-related changes in the esophageal mucosa, such as dilated intercellular spaces. The reliable detection of dilated intercellular spaces at the time of endoscopy would yield a significant diagnostic advantage for separating patients with functional heartburn from the large proportion of patients with gastroesophageal reflux symptoms but no macroscopic esophagitis or pathological acid exposure. The bioimpedance of the esophageal mucosa, measured with a small caliber probe, was evaluated in a series of preclinical experiments. First, sections of rabbit esophageal epithelium were mounted in Ussing chambers and exposed to solutions at pH 7.4 or pH 1.5 for 45 minutes. Impedance measurements were taken at varying probe pressures. Second, rabbit esophageal epithelia were perfused for 45 minutes in situ with pH 1.1 or control solutions and impedance measurements taken. Samples from both in vitro and in situ experiments were taken for morphological examination by light microscopy. Finally, esophageal bioimpedance was measured in awake dogs with permanent esophagocutaneous stoma. The in situ experiments demonstrated that morphological changes in the esophageal mucosa could be discerned by the use of bioimpedance spectroscopy. The variability in resistivity was species-independent but was affected by the pressure applied to the probe. The results suggest that evaluation of bioimpedance spectroscopy for use in a clinical setting is warranted. Small morphological differences in the esophageal mucosa may be detected by the use of bioimpedance spectroscopy.

Electrical tissue impedance spectroscopy: a novel device to measure esophageal mucosal integrity changes during endoscopy

“…Previous investigators proved that with the same technique it was feasible to characterize cervical squamous epithelium and separate cervical intraepithelial neoplasia from normal cervical tissue . Furthermore, previous animal studies performed on esophageal tissue showed that ETIS could detect a decrease in extracellular impedance after perfusion of the esophagus with an acidic solution . This finding corresponds to DIS and increased permeability of rabbit esophagus developing after perfusion with acidic solutions, already suggesting a relation between ETIS results and mucosal integrity.…”

“…The impedance spectra were fitted to a Cole equation as previously described . In this equation it is assumed that tissue impedance can be described as an electrical circuit composed of two resistors in parallel and a capacitator in series.…”

Esophageal intraluminal baseline impedance is associated with severity of acid reflux and epithelial structural abnormalities in patients with gastroesophageal reflux disease

“…Bioimpedance spectroscopy can distinguish squamous epithelium from columnar epithelium in Barrett’s esophagus, which means mucosal structural change such as epithelial metaplasia can be identified by impedance baseline change [7]. Farre et al [1] also demonstrated that impedance baseline measurements can be used to evaluate changes in the integrity of the esophageal mucosa after acid perfusion injury, and showed that baseline impedance is correlated with transepithelial resistance (TER), which reflects impaired mucosal structure.…”

Biomarkers of Reflux Disease

“…Initial animal studies in 2011 yielded encouraging results, and subsequent studies by Weijenborg et al comparing patients with erosive disease and HV, found good correlation between impedance measurements by ETIS (taken in areas of normal appearing mucosa) and traditional transepithelial resistance and permeability measurements obtained in Ussing chamber studies 35, 67, 68 . However, data on patients with NERD and correlations with conventional BI measurements are not yet available.…”