RESUMO
BACKGROUND: Type 1 vanilloid receptors (TRPV1) have been described on esophageal afferent sensitive neurons. Stimulation of TRPV1 receptors with capsaicin may induce heartburn. Capsaicin is the pungent component of chili and the most extensively studied TRPV1 agonist. OBJECTIVES: To investigate the effect of esophageal stimulation with intraesophageal capsaicin administration on induction of esophageal symptoms and on esophageal chemo-sensitization to acid in different gastroesophageal reflux disease (GERD) phenotypes. METHODS: Healthy volunteers and patients with GERD (non-erosive [NERD], erosive GERD [EE] and Barrett's esophagus [BE]) were prospectively studied. All subjects were randomized to receive either intraesophageal perfusion capsaicin or saline 0.9%. Thirty minutes after saline or capsaicin infusion an acid perfusion test of HCl was performed. A week later, a crossover phase with capsaicin versus saline was performed. Five symptoms were evaluated every 5 min during the first 30 minutes after capsaicin, saline, and acid perfusion: chest burning, chest pain, heartburn, epigastric burning, and epigastric pain. RESULTS: 17 healthy subjects and 31 GERD patients (10 NERD, 11 EE, and 10 BE) were included. Twenty- eight (90%) of GERD and 6 (35%) of healthy subjects had esophageal symptoms after capsaicin perfusion. Mean for the 5 evaluated symptoms induced by capsaicin was significantly higher in the GERD group compared to the control group. The highest symptom severity was in the erosive subgroup. Capsaicin decreased the 5 symptoms induced by acid perfusion in both healthy volunteers and GERD patients. Total score of esophageal symptom severity (produced by acid perfusion) was significantly reduced by capsaicin infusion in the BE group. CONCLUSIONS: Capsaicin induces esophageal and gastric symptoms in healthy volunteers and GERD patients. Capsaicin reduces esophageal chemosensitivity to acid, especially in patients with BE.