Published online Dec 15, 2003. doi: 10.3748/wjg.v9.i12.2801
Revised: August 16, 2003
Accepted: October 12, 2003
Published online: December 15, 2003
AIM: Little has been known about the pathogenesis of non-erosive reflux disease (NERD). Recent studies have implicated interleukin 8 (IL-8) in the development and progression of gastroesophgeal reflux disease (GERD). The purpose of this study was to determine IL-8 RNA expression levels in NERD patients with or without subtle mucosal changes.
METHODS: We studied 26 patients with NERD and 13 asymptomatic controls. Biopsy sample was taken from the esophagus 3 cm above the gastroesophageal junction and snap frozen for measurement of IL-8 mRNA levels by real-time quantitative polymerase chain reaction (PCR). We also examined mRNA expression of IL-8 receptors, CXCR-1 and -2 by reverse transcriptase PCR. The patients were endoscopically classified into grade M (mucosal color changes without visible mucosal break) and N (neither minimal involvement nor mucosal break) of the modified Los Angeles classification.
RESULTS: The relative IL-8 mRNA expression levels were significantly higher in esophageal mucosa of NERD patients than those of the controls. There was a significant difference in IL-8 mRNA levels between grade M and N. The CXCR-1 and -2 mRNAs were constitutively expressed in esophageal mucosa.
CONCLUSION: Our results suggest that high IL-8 levels in esophageal mucosa may be involved in the pathogenesis of NERD through interaction with its receptors. NERD seems to be composed of a heterogeneous population in terms of not only endoscopically minimal involvement but also immune and inflammatory processes.