Abstract
Objective. Dilated intercellular space (DIS) in esophageal biopsies is regarded as a possible early sign of mucosal injury in gastroesophageal reflux disease (GERD). This study presents a standardized approach of intercellular space measurement. Material and methods. Distal and proximal esophageal biopsies were taken from 19 patients with suspected GERD, and examined with TEM. A grid containing 150 line-crossing points was applied upon each photomicrograph. The number of points falling on the intercellular space was divided by the total number of points of the grid, thereby creating a ratio called the intercellular space ratio (ISR). The ISR method was validated with regard to intra- and interobserver agreement, and was compared to a widely used method for measuring intercellular space diameter developed by Tobey et al. (Tobey NA, Carson JL, Alkiek RA, Orlando RC. Dilated intercellular spaces: a morphological feature of acid reflux–damaged human esophageal epithelium. Gastroenterology 1996;111(5):1200–1205). The ISR was also compared to other markers for GERD. Results. Pearson's correlation coefficients for intra- and interobserver agreement were 0.91 (p < 0.001) and 0.82 (p < 0.001), respectively. The Pearson's correlation coefficient between the ISR and the intercellular space diameter according to Tobey et al., measured in the same micrographs, was 0.32 (p < 0.001). The proximal ISR correlated significantly with the distal ISR (Spearman's rho = 0.57, p = 0.010), and with heartburn symptom score (Spearman's rho = 0.50, p = 0.028). Conclusions. The ISR showed a high intraobserver and interobserver agreement. It also displayed good external validity when compared to other markers for gastroesophageal reflux. A rather poor correlation was however found between the ISR and the intercellular space diameter measured as described by Tobey et al.
Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.