Stimulated saliva secretion is reduced in proton pump inhibitor-resistant severe reflux esophagitis patients

Abstract

Background Salivary secretion in patients with proton-pump inhibitor (PPI)-resistant severe reflux esophagitis has not been examined. In this study, saliva secretion and salivary epidermal growth factor (EGF) in patients with PPI-resistant severe reflux esophagitis were investigated. Methods We recruited 22 PPI-resistant and 22 PPI-responsive severe reflux esophagitis patients who were not infected with Helicobacter pylori. Saliva secretion testing and esophageal manometry using high-resolution manometry were performed. Saliva secretion was assessed as follows: each patient chewed sugar-free gum for 3 min prior to endoscopy and the amount and pH of saliva as well as the pH of saliva after acid loading as an index of the acid-buffering capacity were measured. The salivary EGF concentration was assessed by ELISA. Results The amount of saliva secreted was significantly lower in the PPI-resistant group than in the PPI-responsive group, with medians (25th-75th percentile) of 3.7 (2.2–6.8) and 4.9 (4.0–7.8) mL, respectively (p = 0.029). Salivary pH was significantly lower in the PPI-resistant group [6.9 (6.7–7.2)] than in the PPI-responsive group [7.2 (7.1–7.4), p = 0.001]. Salivary pH after acid loading was significantly lower in the PPI-resistant group [5.6 (5.3–5.9)] than in the PPI-responsive group [6.4 (6.1–6.5), p = 0.002]. The salivary EGF concentration was significantly higher in the PPI-resistant group [3211.5 (1865.0–4121.5)] than in the PPI-responsive group [1816.0 (1123.5–2792.3), p = 0.041]. No significant differences were observed in the proportion of esophageal motility abnormalities. Conclusion Stimulated saliva secretion was reduced in PPI-resistant severe reflux esophagitis patients.