Abstract
BackgroundPostprandial accumulation of gastric secretions in the proximal stomach above the meal adjacent to the esophagogastric junction (EGJ), referred to as the ‘acid pocket’, has been proposed as a pathophysiological factor in gastro-esophageal reflux disease (GERD) and as a target for GERD treatment. This study assessed the effect of proton pump inhibitor (PPI) therapy on the volume, distribution and acidity of gastric secretions in GERD and healthy subjects (HS).MethodsA randomized, double blind, cross-over study in 12 HS and 12 GERD patients pre-treated with 40 mg pantoprazole (PPI) or placebo b.i.d. was performed. Postprandial secretion volume (SV), formation of a secretion layer and contact between the layer and the EGJ were quantified by Magnetic Resonance Imaging (MRI). Multi-channel pH-monitoring assessed intragastric pH.ResultsA distinct layer of undiluted acid secretion was present on top of gastric contents in almost all participants on and off high-dose acid suppression. PPI reduced SV (193 ml to 100 ml, in HS, 227 ml to 94 ml in GERD; p < 0.01) and thickness of the acid layer (26 mm to 7 mm, 36 mm to 9 mm respectively, p < 0.01). No differences in secretion volume or layer thickness were observed between groups; however, off treatment, contact time between the secretion layer and EGJ was 2.6 times longer in GERD compared to HS (p = 0.012). This was not the case on PPI.ConclusionsMRI can visualize and quantify the volume and distribution dynamics of gastric secretions that form a layer in the proximal stomach after ingestion of a liquid meal. The secretion volume and the secretion layer on top of gastric contents is similar in GERD patients and HS; however contact between the layer of undiluted secretion and the EGJ is prolonged in patients. High dose PPI reduced secretion volume by about 50 % and reduced contact time between secretion and EGJ towards normal levels.Trial registrationNCT01212614.Electronic supplementary materialThe online version of this article (doi:10.1186/s12876-015-0343-x) contains supplementary material, which is available to authorized users.
Highlights
Postprandial accumulation of gastric secretions in the proximal stomach above the meal adjacent to the esophagogastric junction (EGJ), referred to as the ‘acid pocket’, has been proposed as a pathophysiological factor in gastro-esophageal reflux disease (GERD) and as a target for GERD treatment
There was no difference in layer formation, secretion volume, intragastric pH, or gastric emptying between healthy subjects and gastroesophageal reflux disease (GERD) patients on placebo
The results demonstrate that collection of undiluted gastric secretion in the proximal stomach after a meal, a key component of the “acid pocket”, is a normal physiological phenomenon that occurs in both healthy subjects and GERD patients [1,2,3, 20]
Summary
Postprandial accumulation of gastric secretions in the proximal stomach above the meal adjacent to the esophagogastric junction (EGJ), referred to as the ‘acid pocket’, has been proposed as a pathophysiological factor in gastro-esophageal reflux disease (GERD) and as a target for GERD treatment. Postprandial accumulation of acid secretion in the proximal stomach above the meal adjacent to the esophagogastric junction (EGJ), referred to as the “acid pocket”, has been proposed as a pathophysiological factor in gastro-esophageal reflux disease (GERD) [1,2,3,4] and a target for GERD treatment [5,6,7,8,9]. The proximal border of the acid pocket has been shown to encroach on the EGJ in GERD patients such that acid secretions contact the distal esophageal mucosa. This phenomenon has been associated with the presence of reflux esophagitis and Barrett metaplasia [1,2,3,4]
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