Influence of Acid Swallows on the Dynamics of the Upper Esophageal Sphincter

Abstract

Mechanisms of the upper esophageal sphincter (UES) when exposed to acid are still incompletely understood. The presented work investigated the reaction of the UES to acid exposure during swallowing. Ten healthy individuals swallowed ten 2 ml neutral water boli of pH 7, followed by 10 swallows each of different levels of acidity (pH 1.8, pH 3 and pH 5). Effects were analyzed by high-resolution manometry (HRM) for the primary parameter Restitution Time, as well as Resting Pressures, maximal, minimal pressures and time intervals. Restitution Times measured mean values of 12.67 s (SD ± 7.03 s) for pH 1.8, pH 7 = 8.69 s (SD ± 2.72 s), pH 3 = 7.56 s (SD ± 2.23 s) and pH 5 = 7.29 s (SD ± 2.55 s), showing prolonged Restitution Times in the UES when exposed to strong bolus acidity. This difference was significant towards the neutral bolus, but also to less acidic boli (pH 5: p = 0.006, pH 3: p = 0.009, pH 7: p = 0.038). Considerable differences of mean values were found for Post-Swallow Maximum and Period of Sphincter Activity. Also, Pre-Swallow Maximum values were found to be highest with the strongest acid. Relaxation Times showed a slight trend of prolongation for the highest bolus acidity. Prolonged Restitution Times may represent a reflexive protective mechanism triggered by receptors in the pharyngeal mucosa or the UES preventing regurgitation of acid into the pharynx and larynx, besides representing ongoing attempts of acid clearance. Exposure to high levels of acidity by a swallowed bolus does influence UES functions during swallowing.

Recent Progress of SERS Nanoprobe for pH Detecting and Its Application in Biological Imaging

“…The concentration of H + can affect most aspects of cell function [1], such as cell metabolism [15] (the change of the enzyme active site shape, even make its degeneration inactivation), cytoskeleton elements [16], (actin and tubulin, etc.) crosslinking, aggregation, proliferation and migration, the ability of muscle cells to generate tension [17] and the working efficiency of ion selective channels [18]. The pH value of body fluids, organs, different cells and tissues in the organism is usually strictly regulated by acid-base homeostasis, such as lysosome, endoplasmic reticulum (ER), Golgi apparatus, lipid droplets and other organelles.…”

Functional Changes of the Upper Esophageal Sphincter in Gastroesophageal Reflux

“…5 Swallowing a bolus with high levels of acidity does influence UES function, with a prolonged pressure restitution time after swallowing. 14 In patients with obstructive sleep apnea, the esophageal pressure decreases (median reduction of 4.2 mm Hg) during episodes of apnea, which may favor the occurrence of gastroesophageal reflux. However, increases in the UES and in the lower esophageal sphincter (LES) pressure (medi-an of 20.1 mm Hg in UES and of 9.6 mm Hg in LES) promote the antireflux barrier against gastroesophageal and esophagopharyngeal refluxes during apnea.…”

“… 5 Swallowing a bolus with high levels of acidity does influence UES function, with a prolonged pressure restitution time after swallowing. 14 …”

Recent Progress of SERS Nanoprobe for pH Detecting and its Application in Biological Imaging

“…The concentration of H+ can affect most aspects of cell function [12], such as cell metabolism [13] (the change of the enzyme active site shape, even make its degeneration inactivation), cytoskeleton elements [14], (actin and tubulin, etc.) crosslinking, aggregation, proliferation and migration, the ability of muscle cells to generate tension [15] and the working efficiency of ion selective channels [16]. The pH value of body fluids, organs, different cells and tissues in the organism is usually strictly regulated by acid-base homeostasis, such as lysosome, endoplasmic reticulum (ER), Golgi apparatus, lipid droplets and other organelles.…”