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Increased TRPV1 gene expression in esophageal mucosa of patients with non-erosive and erosive reflux disease


Michele Pier Luca Guarino, MD, Dipartimento di Malattie dell’Apparato Digerente, Università Campus Bio-Medico, Via Alvaro del Portillo 200 - 00128 Rome, Italy.
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Background  Transient receptor potential channel vanilloid subfamily member-1 (TRPV1) may play a role in esophageal perception. TRPV1 mRNA and protein expression were examined in the esophageal mucosa of non-erosive reflux disease (NERD) and erosive esophagitis (EE) patients and correlated to esophageal acid exposure.

Methods  Seventeen NERD patients, eight EE patients and 10 healthy subjects underwent endoscopy after a 3-week washout from proton pump inhibitors or H2 antagonists. Biopsies, obtained from the distal esophagus, were used for conventional histology, for Western blot analysis and/or quantitative real-time polymerase chain reaction (qPCR). Overall 13 NERD patients, four EE patients and five controls underwent ambulatory pH-testing.

Key Results  TRPV1 expression was increased in all NERD and EE patients, as measured by Western blot analysis (0.65 ± 0.07 and 0.8 ± 0.05 VS 0.34 ± 0.04 in controls; P < 0.01) and by qPCR (1.98 ± 0.21 and 2.52 ± 0.46 VS 1.00 ± 0.06; P < 0.01). Neutrophilic infiltration, in the mucosa, was detected only in EE patients.

Conclusions & Inferences  Non-erosive reflux disease and EE patients presented increased TRPV1 receptors mRNA and protein, although no correlation with acid exposure was demonstrated. Increased TRPV1 in the esophageal mucosa may contribute to symptoms both in NERD and EE patients and possibly account for peripheral mechanisms responsible for esophageal hypersensitivity in NERD patients.