The gastric accommodation response to meal intake determines the occurrence of transient lower esophageal sphincter relaxations and reflux events in patients with gastro-esophageal reflux disease

BackgroundGastro-esophageal reflux (GER), the retrograde flow of gastric contents into the esophagus is a physiologic phenomenon, which can evoke symptoms and/or lesions in the esophagus (=gastro-esophageal reflux disease or GERD). Proton pump inhibitors (PPIs) reduce gastric acidity; however, as they are unable to control transient lower esophageal sphincter relaxations (TLESRs), the main mechanism for reflux in GERD, they do not abolish reflux. TLESRs occur predominantly in the postprandial period, and they are believed to be triggered by gastric distention. Gastric accommodation (GA) is the physiologic response to gastric distention and serves to prevent a rise in gastric wall tension during food intake. We aimed to study the relationship between GA and TLESRs, as they both are triggered by gastric distention. MethodsWe studied 12 GERD patients (average age 37years [range 18-62], 7m/5f) and nine healthy volunteers (average age 27years [range 22-36], 2m/7f) using high resolution manometry-impedance measurement before and after a mixed meal challenge. We determined the number of TLESRs (with or without reflux) and measured pre- and postprandial IGP. The change in IGP between the pre- and postprandial period (IGP) is used as surrogate for GA. We also measured LES pressure before and after the meal and calculated the change (LESp). Key ResultsThere were no statistical differences between pre- and postprandial IGP in GERD and healthy volunteers and similarly, there was no significant difference between pre- and postprandial LES pressures in GERD patients and healthy volunteers. The number of TLESRs (with or without reflux) was similar in GERD and healthy volunteers. More importantly, we did observe a negative correlation between IGP and the number of TLESRs, irrespective of whether they were associated with reflux or not, in the GERD patients (without reflux r=-0.67, p=0.017; with reflux r=-0.81, p=0.0014). The same observations were found in healthy volunteers, where IGP and the number of TLESRs are significantly inversely correlated (without reflux r=-0.87, p=0.0045; with reflux r=-0.75, p=0.021). We could not establish a correlation between LESp and the number of TLESRs, neither in GERD patients nor in healthy volunteers. Conclusions & InferencesThis is the first study showing a clear negative correlation between IGP and the number of TLESRs, irrespective of whether they were associated with reflux or not, both in GERD patients and in healthy subjects. These results suggest that TLESRs and GA are closely linked, probably through activation of mechanoreceptors involved in triggering of TLESRs.