Stimulation and characteristics of secondary oesophageal peristalsis in normal subjects

Influence of Menthol Infusion on Esophageal Peristalsis in Patients With Ineffective Esophageal Motility

Background/Aims

Activation of the cold receptor, transient receptor potential melastatin 8 (TRPM8) by menthol inhibits esophageal secondary peristalsis in healthy adults. Ineffective esophageal motility (IEM) is common. This study is to evaluate the effects of acute infusion of menthol on esophageal peristalsis in patients with IEM.

Methods

Twenty patients with IEM (males 11, mean age 36) were studied for esophageal peristalsis using high-resolution manometry. All participant had primary peristalsis performed with 10 water swallows and secondary peristalsis generated with 10 rapid air injections of 20 mL via mid-esophageal infusion port. Two different sessions by randomly performing acute administration of placebo or menthol (3 mM) were used for testing their effects on esophageal peristalsis.

Results

Menthol infusion had no effects on distal contractile integral (P = 0.471), distal latency (P = 0.58), or complete peristalsis (P = 0.251). Menthol infusion did not change basal lower esophageal sphincter pressure (P = 0.321), esophagogastric junction contractile integral (P = 0.758), or integrated relaxation pressure (P = 0.375) of primary peristalsis, but reduced upper esophageal sphincter pressure (P = 0.037). Infusion of menthol significantly reduced the frequency of secondary peristalsis for air injects of 20 mL (P = 0.002), but did not affect distal contractile integral of secondary peristalsis for air injections of 20 mL.

Conclusion

This work has suggested that activation of TRPM8 by menthol can attenuate mechanosensitivity of secondary peristalsis in response to rapid air distension regardless of the presence of IEM.

Relevance of ineffective esophageal motility to striated esophageal muscle contraction: Studies with high-resolution manometry

Striated esophageal muscle contraction (SEC) is important for pharyngeal swallowing and deglutition augmentation against aspiration. Its clinical relevance is unclear in patients with ineffective esophageal motility (IEM). In this study, we aimed to characterize and compare SEC in consecutive patients with and without IEM. All eligible patients were evaluated for SEC, primary and secondary peristalsis using high-resolution manometry (HRM) with one mid-esophageal injection port. Primary peristalsis was assessed with 10 5-mL liquid swallows and multiple rapid swallows (MRS), while secondary peristalsis was performed with rapid air injections of 20 mL. All peristatic parameters of HRM were measured, and SEC and its contractile integral (SECI) were evaluated. One hundred and forty patients (59.3% women, mean age 46.1 ± 13.1 years) were included. There was no difference in SECI between patients with and without IEM (p = 0.91). SECI was also similar between patients with and without secondary peristalsis for IEM (p = 0.63) or normal motility (p = 0.80). No difference in SECI was seen between patients with and without MRS for IEM (p = 0.55) or normal motility (p = 0.88). SECI was significantly higher in male patients than female patients in IEM patients (p = 0.01). SECI significantly correlated with age in patients with normal motility (r = -0.31, p = 0.01). Aging may have a negative impact on SEC in patients with normal motility, while gender difference in SECI occurs in IEM patients. Neither secondary peristalsis nor MRS influences SECI.

Modification of the Biorelevant Release Testing of Esophageal Applied Mucoadhesive Films and Development of Formulation Strategies to Increase the Mucosal Contact Time

The increasing prevalence of esophageal disease highlights the clinical relevance of novel, long-lasting mucoadhesive oral dosage forms. The EsoCap device enables targeted local application of films in the esophagus. Biorelevant test systems such as EsoPeriDiss are essential for early formulation development. To this end, the developed and already described release model for simulating the esophagus is being further developed for its potential for biorelevant mapping of the application site through complete tempering and investigation of biorelevant release media. Particularly viscous saliva formulations led to an extension of the retention time. In addition, possible formulation strategies for increasing the retention time of esophageal applied films are being evaluated, such as different film thicknesses, polymer grades and the influence of different active ingredient properties on the retention time. For highly soluble active ingredients, the film thickness represents an option for extending the retention time, while for less soluble substances, the choice of polymer grade may be of particular interest.

Enhancing Chicago Classification diagnoses with functional lumen imaging probe-mechanics (FLIP-MECH)

BACKGROUND

Esophageal motility disorders can be diagnosed by either high-resolution manometry (HRM) or the functional lumen imaging probe (FLIP) but there is no systematic approach to synergize the measurements of these modalities or to improve the diagnostic metrics that have been developed to analyze them. This work aimed to devise a formal approach to bridge the gap between diagnoses inferred from HRM and FLIP measurements using deep learning and mechanics.

METHODS

The "mechanical health" of the esophagus was analyzed in 740 subjects including a spectrum of motility disorder patients and normal subjects. The mechanical health was quantified through a set of parameters including wall stiffness, active relaxation, and contraction pattern. These parameters were used by a variational autoencoder to generate a parameter space called virtual disease landscape (VDL). Finally, probabilities were assigned to each point (subject) on the VDL through linear discriminant analysis (LDA), which in turn was used to compare with FLIP and HRM diagnoses.

RESULTS

Subjects clustered into different regions of the VDL with their location relative to each other (and normal) defined by the type and severity of dysfunction. The two major categories that separated best on the VDL were subjects with normal esophagogastric junction (EGJ) opening and those with EGJ obstruction. Both HRM and FLIP diagnoses correlated well within these two groups.

CONCLUSION

Mechanics-based parameters effectively estimated esophageal health using FLIP measurements to position subjects in a 3-D VDL that segregated subjects in good alignment with motility diagnoses gleaned from HRM and FLIP studies.

The impact of primary peristalsis, contractile reserve, and secondary peristalsis on esophageal clearance measured by timed barium esophagogram

BACKGROUND

Primary and secondary peristalsis facilitate esophageal bolus transport; however, their relative impact for bolus clearance remains unclear. We aimed to compare primary peristalsis and contractile reserve on high-resolution manometry (HRM) and secondary peristalsis on functional lumen imaging probe (FLIP) Panometry with emptying on timed barium esophagogram (TBE) and incorporate findings into a comprehensive model of esophageal function.

METHODS

Adult patients who completed HRM with multiple rapid swallows (MRS), FLIP, and TBE for esophageal motility evaluation and without abnormal esophagogastric junction outflow/opening or spasm were included. An abnormal TBE was defined as a 1-min column height >5 cm. Primary peristalsis and contractile reserve after MRS were combined into an HRM-MRS model. Secondary peristalsis was combined with primary peristalsis assessment to describe a complementary neuromyogenic model.

KEY RESULTS

Of 89 included patients, differences in rates of abnormal TBEs were observed with primary peristalsis classification (normal: 14.3%; ineffective esophageal motility: 20.0%; absent peristalsis: 54.5%; p = 0.009), contractile reserve (present: 12.5%; absent: 29.3%; p = 0.05), and secondary peristalsis (normal: 9.7%; borderline: 17.6%; impaired/disordered: 28.6%; absent contractile response: 50%; p = 0.039). Logistic regression analysis (akaike information criteria, area under the receiver operating curve) demonstrated that the neuromyogenic model (80.8, 0.83) had a stronger relationship predicting abnormal TBE compared to primary peristalsis (81.5, 0.82), contractile reserve (86.8, 0.75), or secondary peristalsis (89.0, 0.78).

CONCLUSIONS AND INFERENCES

Primary peristalsis, contractile reserve, and secondary peristalsis were associated with abnormal esophageal retention as measured by TBE. Added benefit was observed when applying comprehensive models to incorporate primary and secondary peristalsis supporting their complementary application.

Development of Test Programs for the Biorelevant Characterization of Esophageal-Applied Dosage Forms

In the local treatment of the esophageal mucosa, the retention time of the different dosage forms, such as tablets, films or liquids, is of high relevance for the effective treatment of diseases. Unfortunately, there are only few in vitro models describing the esophageal route of administration. To predict the behaviour of an esophageal-applied dosage form, it is necessary to simulate the site of application in a biorelevant way. The aim of this work was to develop two test setups for an esophageal peristalsis model which was described in a previous study. Different parameters such as flow rate, peristalsis, angle of inclination or mucous membrane were varied or introduced into the model. A stimulated and unstimulated modus were developed and tested with two different dosage forms. The time until the dosage form was cleared from the in vitro model was shorter with the stimulated than with the unstimulated modus. Also, esophageal-applied films had a prolonged transit time compared to a viscous syrup. The modification of the simulated esophageal surface made it possible to estimate the retention time of the dosage forms. It could be demonstrated that the residence time of a dosage form depends on different parameters affecting each other.

An artificial intelligence platform provides an accurate interpretation of esophageal motility from Functional Lumen Imaging Probe Panometry studies

BACKGROUND

Functional lumen imaging probe (FLIP) Panometry is performed at the time of sedated endoscopy and evaluates esophageal motility in response to distension. This study aimed to develop and test an automated artificial intelligence (AI) platform that could interpret FLIP Panometry studies.

METHODS

The study cohort included 678 consecutive patients and 35 asymptomatic controls that completed FLIP Panometry during endoscopy and high-resolution manometry (HRM). "True" study labels for model training and testing were assigned by experienced esophagologists per a hierarchical classification scheme. The supervised, deep learning, AI model generated FLIP Panometry heatmaps from raw FLIP data and based on convolutional neural networks assigned esophageal motility labels using a two-stage prediction model. Model performance was tested on a 15% held-out test set (n = 103); the remainder of the studies were utilized for model training (n = 610).

KEY RESULTS

"True" FLIP labels across the entire cohort included 190 (27%) "normal," 265 (37%) "not normal/not achalasia," and 258 (36%) "achalasia." On the test set, both the Normal/Not normal and the achalasia/not achalasia models achieved an accuracy of 89% (with 89%/88% recall, 90%/89% precision, respectively). Of 28 patients with achalasia (per HRM) in the test set, 0 were predicted as "normal" and 93% as "achalasia" by the AI model.

CONCLUSIONS

An AI platform provided accurate interpretation of FLIP Panometry esophageal motility studies from a single center compared with the impression of experienced FLIP Panometry interpreters. This platform may provide useful clinical decision support for esophageal motility diagnosis from FLIP Panometry studies performed at the time of endoscopy.

Phosphodiesterase 5 (PDE-5) inhibitors (sildenafil, tadalafil, and vardenafil) effects on esophageal motility: a systematic review

BACKGROUND

Esophageal motility disorders are a group of disorders associated with dysfunctional swallowing resulting from impaired neuromuscular coordination. Phosphodiesterase 5 (PDE-5) inhibitors induce smooth relaxation and are proposed as a treatment option for esophageal motility disorders such as achalasia.

METHODS

This study is conducted based on the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA). We systematically searched MEDLINE/ PubMed, Scopus, EMBASE, and Web of Science databases for esophageal outcomes of individuals treated with PDE5 inhibitors. A random effect meta-analysis was conducted.

RESULTS

A total of 14 studies were included. They were conducted in different countries, with Korea and Italy having the highest number of articles. The main drug assessed was sildenafil. PDE-5 inhibitors resulted in a significant reduction in lower esophageal sphincter pressure (SMD - 1.69, 95% CI: -2.39 to -0.99) and the amplitude of contractions (SMD - 2.04, 95% CI: -2.97 to -1.11). Residual pressure was not significantly different between the placebo and sildenafil groups (SMD - 0.24, 95% CI: -1.20 to 0.72). Furthermore, a recent study reported contractile integral, stating that ingestion of sildenafil leads to a significant reduction in distal contractile integral and a significant increase in proximal contractile integral.

CONCLUSION

PDE-5 inhibitors significantly reduce LES resting pressure and esophageal peristaltic vigor, decreasing esophageal body contractility and contraction reserve. Therefore, using these drugs in patients affected by esophageal motility disorders may potentially improve their condition regarding symptom relief and prevention of further associated complications. Future reports investigating larger sample size is necessary in order to establish definite evidence regarding the efficacy of these drugs.

Pathophysiology of Pediatric Gastroesophageal Reflux Disease: Similarities and Differences With Adults

Gastroesophageal reflux (GOR) is defined as "the passage of gastric contents into the esophagus with or without regurgitation and vomiting" and gastroesophageal reflux disease (GORD) is defined "when GOR leads to troublesome symptoms affecting the daily functioning and/or complications." This definition was first developed in 2006 by the Montreal consensus group (1) and later on adopted by pediatric gastroenterology societies such as ESPGHAN and NASPGHAN in 2009 (2). The definition of gastroesophageal reflux reveals little about its pathophysiology and is focused on symptomatology. In this way, it acts as an umbrella term for the multifactorial causes of the disease and the various phenotypes encountered; from functional heartburn to hypersensitive esophagus and nonerosive reflux disease, to erosive esophagitis and Barrett's esophagus. This article is devoted to the pathophysiology of pediatric GORD in comparison to adult GORD and is divided in 2 parts. In the first part, we will systematically describe the different mechanisms for the generation and clearance of reflux events, while on the second part we will discuss the mechanisms involved in symptoms generation. Finally, we will discuss the similarities and differences between pediatric and adult GORD.

Validation of secondary peristalsis classification using FLIP panometry in 741 subjects undergoing manometry

BACKGROUND AND AIMS

This study aimed to systematically evaluate a classification scheme of secondary peristalsis using functional luminal imaging probe (FLIP) panometry through comparison with primary peristalsis on high-resolution manometry (HRM).

METHODS

706 adult patients that completed FLIP and HRM for primary esophageal motility evaluation and 35 asymptomatic volunteers ("controls") were included. Secondary peristalsis, that is, contractile responses (CRs), was classified on FLIP panometry by the presence and pattern of contractility as normal (NCR), borderline (BCR), impaired/disordered (IDCR), absent (ACR), or spastic-reactive (SRCR). Primary peristalsis on HRM was assessed according to the Chicago Classification.

RESULTS

All 35 of the controls had antegrade contractions on FLIP panometry with either NCR (89%) or BCR (11%). The average percentages of normal swallows on HRM varied across contractile response patterns from 84% in NCR, 68% in BCR, 39% in IDCR, to 11% in ACR, as did the percentage of failed swallows on HRM: 4% in NCR, 12% in BCR, 36% in IDCR, and 79% in ACR. SRCR on FLIP panometry was observed in 18/57 (32%) patients with type III achalasia, 4/15 (27%) with distal esophageal spasm, and 7/15 (47%) with hypercontractile esophagus on HRM.

CONCLUSIONS

The FLIP panometry contractile response patterns reflect a pathophysiologic transition from normal to abnormal esophageal peristaltic function with shared features with primary peristaltic function/dysfunction on HRM. Thus, these patterns of the contractile response to distension can facilitate the evaluation of esophageal motility using FLIP panometry.

Effects of codeine on esophageal peristalsis in humans using high resolution manometry

BACKGROUND AND AIM

Opioid receptors agonists have been demonstrated to impair lower esophageal sphincter (LES) relaxation and induce spastic esophageal dysmotility, but little was known for their impact on distension-induced secondary peristalsis. The aim of the study was to investigate the hypothesis whether acute administration of codeine can influence physiological characteristics of primary and secondary peristalsis in healthy adults.

METHODS

Eighteen healthy volunteers (13 men, mean age 27.5 years, aged 20-43 years) underwent high resolution manometry (HRM) with a catheter containing an injection port in mid-esophagus. Secondary peristalsis was performed with 10 and 20 mL rapid air injections. Two different sessions including acute administration of codeine (60 mg) or the placebo were randomly performed.

RESULTS

Codeine significantly increased 4-s integrated relaxation pressure (IRP-4s) (P = 0.003) and shortened distal latency (DL) (P = 0.003) of primary peristalsis. The IRP-4s of secondary peristalsis was also significantly higher after codeine than the placebo during air injections with 10 mL (P = 0.048) and 20 mL (P = 0.047). Codeine significantly increased the frequency of secondary peristalsis during air injections with 10 mL than the placebo (P = 0.007), but not for air injection with 20 mL (P = 0.305).

CONCLUSIONS

In addition to impair LES relaxation and reduce distal latency of primary peristalsis, codeine impairs LES relaxation of secondary peristalsis and increases secondary peristaltic frequency. Our study supports the notion in human esophagus that the impact of opioids on peristaltic physiology appears to be present in both primary and secondary peristalsis.

Effect of prucalopride on sildenafil-induced inhibition of esophageal peristalsis in healthy adults

BACKGROUND AND AIM

Prucalopride, a high-affinity 5-hydroxytryptamine 4 receptor agonist, promotes esophageal peristalsis, while phosphodiesterase type 5 inhibitor sildenafil inhibits esophageal peristalsis. The present study was aimed to evaluate whether prucalopride would augment esophageal peristalsis subsequent to the application of sildenafil.

METHODS

Seventeen healthy adults underwent high-resolution manometry by a catheter with one injection port located in the mid-esophagus. Secondary peristalsis was assessed by rapid air injections after water swallows. Two sessions were randomly performed including acute administration of sildenafil 50 mg after pretreatment with prucalopride or the placebo.

RESULTS

The frequency of primary peristalsis subsequent to the administration of sildenafil was significantly increased by prucalopride (P = 0.02). Prucalopride also significantly increased distal contractile integral of primary peristalsis subsequent to the administration of sildenafil (P = 0.03). No difference in the frequency of secondary peristalsis subsequent to the administration of sildenafil for air injects of 10 mL (P = 0.14) or 20 mL (P = 0.21) was found between prucalopride and placebo. Prucalopride did not change distal contractile integral of secondary peristalsis subsequent to the administration of sildenafil for air injections of 10 mL (P = 0.09) or 20 mL (P = 0.12).

CONCLUSIONS

Prucalopride modulates sildenafil-induced inhibition of primary peristalsis by increasing its effectiveness and peristaltic wave amplitude. Our findings suggest that activation of 5-hydroxytryptamine 4 receptors plays a role in mediating sildenafil-induced inhibition of esophageal primary peristalsis rather than secondary peristalsis.

Impact of ineffective esophageal motility on secondary peristalsis: Studies with high-resolution manometry

BACKGROUND/AIM

The aim was to investigate whether there is a difference in secondary peristalsis on high-resolution manometry (HRM) among gastroesophageal reflux disease (GERD) patients with and without ineffective esophageal motility (IEM), and healthy individuals.

METHODS

Twenty-eight GERD patients and seventeen healthy controls were included. Secondary peristalsis was stimulated by a rapid injection of 20 ml air in mid-esophagus. We compared HRM metrics and the response and effective rate of triggering secondary peristalsis between patients with and without IEM and healthy controls.

RESULTS

Sixteen patients had IEM, and the remaining 12 had normal manometry. By triggering of secondary peristalsis, patients without IEM and healthy controls had significantly higher distal contractile integral (DCI) values than IEM patients (p = 0.006). A successful secondary peristalsis was triggered more frequently in healthy controls than in GERD patients with normal peristalsis or IEM (56.9% vs. 20.2% vs. 9.1%, all p < 0.001). The effective rate which determined as DCI > 450 mm Hg.cm.s was higher in healthy controls compared to patients with normal peristalsis (36.5% vs. 19.4%, p < 0.001) and IEM (36.5% vs. 6.3%, p < 0.001). Patients with IEM had lower successful triggering response (9.1% vs. 20.2%) and effective secondary peristalsis (6.3% vs. 19.4%) compared with patients without IEM (p < 0.001).

CONCLUSIONS

Our work has demonstrated that GERD patients, in particular those with IEM, have significant defects in the triggering of secondary peristalsis on HRM. HRM helps characterize esophageal secondary peristalsis which exhibits differently in patients with and without IEM.

Effects of phosphodiesterase-5 inhibitor sildenafil on esophageal secondary peristalsis: Studies with high-resolution manometry

BACKGROUND AND AIM

Secondary peristalsis contributes to the clearance of retained refluxate from the esophagus. Sildenafil, a phosphodiesterase-5 inhibitor, inhibits primary esophageal peristalsis, but its effects on secondary peristalsis remain unknown. This study sought to investigate whether sildenafil could influence physiological characteristics of secondary peristalsis by applying high-resolution manometry (HRM).

METHODS

Seventeen healthy volunteers (15 men and 2 women, aged 30.2 ± 6.4 years) underwent two HRM studies on separate days following the administration of either a placebo or 50 mg of sildenafil in a random order. Both studies were performed using a water-perfused HRM catheter containing one air injection channel positioned in the mid-esophagus. Secondary peristalsis was stimulated by a rapid mid-esophageal injection of 10 or 20 mL of air 1 h after the administration of either the placebo or sildenafil. The frequency and distal contractile integral of secondary peristalsis were then compared.

RESULTS

Complete secondary peristalsis triggered by the 20-mL air injection was more frequent than observed with the 10-mL air injection (P < 0.001). The vigor of secondary peristalsis triggered by the injection of either volume of air was lower than that of primary peristalsis (P < 0.001). Sildenafil significantly reduced the success rate (P ≤ 0.001) and vigor (P < 0.001) of secondary peristalsis relative to the effects of the placebo at both distension volumes.

CONCLUSIONS

Secondary peristalsis can be successfully triggered by rapid air injection during HRM. Sildenafil reduces both the success rate and the vigor of secondary peristalsis, similar to that seen with primary peristalsis.

Endoscope presence during endoluminal functional lumen imaging probe (FLIP) influences FLIP metrics in the evaluation of esophageal dysmotility

BACKGROUND

The functional lumen imaging probe (FLIP) system is an FDA-approved tool for dynamic evaluation of the esophagogastric junction (EGJ). Even though commercially available since 2009, FLIP utilization remains low, partly due to lack of consensus in methodology and interpretation. Therefore, we aimed to analyze the influence of concurrent endoscopy on FLIP measurements.

METHODS

In this single-center study, we reviewed data from 93 patients undergoing FLIP for symptomatic esophageal motility disorders between 2016 and 2018. During sedated endoscopy, we measured luminal values (distensibility, cross-sectional area (CSA), and balloon pressure) at the EGJ and distal esophagus using 30, 40, and 50 mL distension volumes, with and without concurrent endoscope presence. All recorded values were compared at the various distension volumes between the two measurements using a Wilcoxon rank sum test.

KEY RESULTS

There was a significant difference in distensibility and CSA with index distension volume (40 mL) at the EGJ comparing the two measurements: Lower median distensibility was 2.1 mm²  mm Hg^-1 in the group with concurrent inserted endoscope, respectively, 3.4 mm²  mm Hg^-1 without endoscope (P < .001), and median CSA was 86.0 resp. 110.0 mm² (P < .001). No significant difference could be found in the measurements of the distal esophagus.

CONCLUSIONS & INFERENCES

Our results show a significant difference in FLIP measurements with and without endoscope presence. This underlines the importance of establishing a consensus of a standardized FLIP protocol to define normal luminal values and guiding future FLIP diagnostic studies.

Temporal Relationship Between Night-Time Gastroesophageal Reflux Events and Arousals From Sleep

INTRODUCTION

Night-time gastroesophageal reflux (nGER) symptoms are commonly associated with interrupted sleep. Most studies attempting to understand the relationship between sleep, arousal, and nGER events have been performed so using accelerometry; however, this technology is limited in its ability to precisely determine the temporal association between sleep and reflux events. We aimed to examine the temporal relationships between nGER events and arousal/awakening from sleep using high resolution, in-laboratory polysomnography (PSG).

METHODS

Individuals between 18 and 70 years who had undergone a gastroscopy within 12 months underwent simultaneous 24-hour pH/impedance monitoring and in-laboratory PSG. The temporal relationship between each nGER event and sleep/arousals/awakenings was determined for each participant. Analyses were limited to the sleep period (between "lights out" and time of final waking).

RESULTS

Analyses were conducted on the data from 25 individuals, 64% of whom had nGER episodes (5 ± 5 events per person, range 1-18) and 64% of whom had obstructive sleep apnea (OSA, mean apnea-hypopnea index 20 ± 11 events/hr, range 6-44). There were no differences in PSG-determined sleep duration, sleep efficiency, sleep architecture, arousals/awakenings, or sleep apnea severity between those with nGER and those without. Most nGER events (82%) occurred during a PSG epoch that had been classified as wake. Arousals/awakenings preceded almost all events (73/76), whereas fewer had an arousal/awakening after the event (15/76).

DISCUSSION

As opposed to what is typically assumed, nGER does not seem to cause arousal from sleep, but rather arousal from sleep predisposes to nGER.

Effects of esophageal acid infusion vs mosapride on distension-induced secondary peristalsis in humans

Secondary peristalsis contributes to the clearance of the refluxate from the esophagus. Acute administration of 5-hydroxytryptamine 4 (5-HT₄ ) receptors agonist, mosapride or esophageal infusion of hydrochloric acid (HCl) facilitates secondary peristalsis. The aim of this study was to determine whether esophageal acid infusion and administration of mosapride had different effects on secondary peristalsis. Secondary peristalsis was performed with esophageal distension with rapid and slow air injections in 16 healthy subjects. We performed two separate sessions with HCl (0.1 N) and 40 mg oral mosapride to compare their influence on secondary peristaltic parameters. The threshold volume of secondary peristalsis was significantly lower with HCl infusion than mosapride (P = 0.01) by slow air injections. The threshold volume to generate secondary peristalsis was significantly lower with HCl infusion than mosapride (P = 0.002) by rapid air injections. More secondary peristalsis was trigged by rapid air injections after HCl infusion than mosapride (P = 0.003). Infusion of HCl or mosapride administration has similar effects on peristaltic wave amplitude and duration of primary and secondary peristalsis. Acute esophageal acid infusion can induce greater mechanosensitivity to distension-induced secondary peristalsis than 5-HT₄ receptors agonist mosapride. The data suggest that acid-sensitive afferents are more likely to contribute to sensory modulation of esophageal secondary peristalsis; however, the motility aspects of secondary peristalsis are comparable between acute esophageal acidification and 5-HT₄ receptors activation via mosapride.

Gamma-aminobutyric acid receptor type B agonist baclofen inhibits acid-induced excitation of secondary peristalsis but not heartburn sensation

BACKGROUND AND AIM

Acute esophageal acid infusion promotes distension-induced secondary peristalsis. The gamma-aminobutyric acid receptor type B (GABA-B) receptors activation inhibits secondary peristalsis. This study aimed to test the hypothesis whether acid excitation of secondary peristalsis can be influenced by baclofen.

METHODS

Secondary peristalsis was performed with intra-esophageal slow and rapid air injections in 13 healthy subjects. Direct esophageal infusion of 0.1 N HCl following pretreatment with placebo or baclofen was randomly performed at least 1 week apart. Symptom intensity, distension thresholds, and peristaltic parameters were determined and compared between each study protocol.

RESULTS

The intensity of heartburn symptom in response to esophageal acid infusion was significantly greater with baclofen than the placebo (P = 0.002). The threshold volume of secondary peristalsis during slow air injections in response to acid infusion was significantly greater with baclofen than the placebo (P = 0.001). Baclofen significantly increased the threshold volume of secondary peristalsis during rapid air injections in response to acid infusion (P = 0.001). The frequency of secondary peristalsis in response to acid infusion was significantly decreased by baclofen as compared with the placebo (P = 0.001). Baclofen significantly decreased peristaltic amplitudes in response to acid infusion during rapid air injections (P = 0.007).

CONCLUSIONS

Gamma-aminobutyric acid receptor type B agonist baclofen inhibits acid excitation of secondary peristalsis in human esophagus, which is probably mediated by both muscular and mucosal mechanoreceptors. This work supports the evidence of potential involvement of GABA-B receptors in negative modulation of acid excitation of esophageal perception as well as secondary peristalsis.

Axial Movements and Length Changes of the Human Lower Esophageal Sphincter During Respiration and Distension-induced Secondary Peristalsis Using Functional Luminal Imaging Probe

Background/Aims

Efficient transport through the esophago-gastric junction (EGJ) requires synchronized circular and longitudinal muscle contraction of the esophagus including relaxation of the lower esophageal sphincter (LES). However, there is a scarcity of technology for measuring esophagus movements in the longitudinal (axial) direction. The aim of this study is to develop new analytical tools for dynamic evaluation of the length change and axial movement of the human LES based on the functional luminal imaging probe (FLIP) technology and to present normal signatures for the selected parameters.

Methods

Six healthy volunteers without hiatal hernia were included. Data were analyzed from stepwise LES distensions at 20, 30, and 40 mL bag volumes. The bag pressure and the diameter change were used for motion analysis in the LES. The cyclic bag pressure frequency was used to distinguish dynamic changes of the LES induced by respiration and secondary peristalsis.

Results

Cyclic fluctuations of the LES were evoked by respiration and isovolumetric distension, with phasic changes of bag pressure, diameter, length, and axial movement of the LES narrow zone. Compared to the respiration-induced LES fluctuations, peristaltic contractions increased the contraction pressure amplitude (P < 0.001), shortening (P < 0.001), axial movement (P < 0.001), and diameter change (P < 0.01) of the narrow zone. The length of the narrow zone shortened as function of the pressure increase.

Conclusions

FLIP can be used for evaluation of dynamic length changes and axial movement of the human LES. The method may shed light on abnormal longitudinal muscle activity in esophageal disorders.

Influence of prucalopride on esophageal secondary peristalsis in reflux patients with ineffective motility

BACKGROUND AND AIM

Ineffective esophageal motility (IEM) is associated with gastroesophageal reflux disease. Secondary peristalsis contributes to esophageal clearance. Prucalopride promotes secondary peristalsis by stimulating 5-hydroxytrypatamine 4 receptors in the esophagus. We aimed to determine whether prucalopride would augment secondary peristalsis in gastroesophageal reflux disease patients with IEM.

METHODS

After a baseline recording of primary peristalsis, secondary peristalsis was stimulated by slow and rapid mid-esophageal injections of air in 15 patients with IEM. Two separate sessions with 4-mg oral prucalopride or placebo were randomly performed.

RESULTS

Prucalopride significantly increased primary peristaltic wave amplitude (68.1 ± 10.0 vs 55.5 ± 8.8 mmHg, P = 0.02). The threshold volume for triggering secondary peristalsis was significantly decreased by prucalopride during slow (9.3 ± 0.8 vs 12.0 ± 0.8 mL; P = 0.04) and rapid air injection (4.9 ± 0.3 vs 7.1 ± 0.1 mL; P = 0.01). Secondary peristalsis was triggered more frequently after application of prucalopride (55% [43-70%]) than placebo (45% [33-50%]) (P = 0.008). Prucalopride did not change pressure wave amplitudes during slow air injection (84.6 ± 8.1 vs 57.4 ± 13.8 mmHg; P = 0.19) or pressure wave amplitudes during rapid air injection (84.2 ± 8.6 vs 69.5 ± 12.9 mmHg; P = 0.09).

CONCLUSIONS

Prucalopride enhances primary peristalsis and mechanosensitivity of secondary peristalsis with limited impact on secondary peristaltic activities in IEM patients. Our study suggests that prucalopride appears to be useful in augmenting secondary peristalsis in patients with IEM only via sensory modulation of esophageal secondary peristalsis.

Influence of GABA-B Agonist Baclofen on Capsaicin-Induced Excitation of Secondary Peristalsis in Humans

OBJECTIVES

Esophageal instillation of capsaicin enhances secondary peristalsis, but the γ-aminobutyric acid receptor type B (GABA-B) agonist baclofen inhibits secondary peristalsis. This study aimed to investigate whether baclofen could influence heartburn perception and secondary peristalsis subsequent to capsaicin infusion in healthy adults.

METHODS

Secondary peristalsis was performed by slow and rapid mid-esophagus air injections in 15 healthy subjects. Two different sessions including esophageal infusion of capsaicin-containing red pepper sauce (0.84 mg) following pre-treatment with placebo or baclofen were randomly performed to test the effects on heartburn perception and secondary peristalsis.

RESULTS

The intensity of heartburn symptom subsequent to capsaicin infusion was significantly greater after pre-treatment of baclofen as compared with the placebo (P=0.03). Baclofen significantly increased the threshold volume of secondary peristalsis to slow air injections subsequent to esophageal capsaicin infusion (P<0.001). Baclofen significantly increased the threshold volume of secondary peristalsis to rapid air injections subsequent to esophageal capsaicin infusion (P<0.01). The frequency of secondary peristalsis subsequent to capsaicin infusion was significantly decreased with baclofen as compared with the placebo (P<0.002). Baclofen had no effect on any of the peristaltic parameters of secondary peristalsis subsequent to capsaicin infusion.

CONCLUSIONS

The GABA-B agonist baclofen appears to attenuate the esophagus to capsaicin-induced excitation of secondary peristalsis in healthy adults. Our study suggests the inhibitory modulation for GABA-B receptors on capsaicin-sensitive afferents mediating secondary peristalsis in human esophagus.

Altered oesophageal mechanosensitivity of secondary peristalsis as a pathophysiological marker in patients with globus sensation

OBJECTIVE

Secondary peristalsis is important for clearance of retained food bolus and refluxate from the oesophagus. We aimed to investigate whether patients with globus sensation have altered physiological characteristics of secondary peristalsis.

DESIGN

Prospective case-controlled study SETTING: Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan.

PARTICIPANTS

Seventeen globus patients and 18 healthy controls.

MAIN OUTCOME MEASURES

After a baseline recording of primary peristalsis, secondary peristalsis was stimulated with slow and rapid mid-oesophageal injections of air. Distension thresholds and peristaltic activities of secondary peristalsis were analysed and compared between the patients and healthy controls.

RESULTS

The threshold volume for generating secondary peristalsis during slow air distension did not differ between the patient and control groups (P = .55). The threshold volume for generating secondary peristalsis during rapid air distension was significantly greater in patients with globus than healthy controls (7.0 ± 0.9 vs 5.0 ± 0.3 mL, P = .04). Secondary peristalsis was triggered less frequently in globus patients as compared with healthy control after rapid air distension (40% [30%-65%] vs 60% [60%-83%], P = .001). There was no difference in any of peristaltic parameters for primary and secondary peristalsis between the groups.

CONCLUSIONS

Our work identifies functional defects of oesophageal secondary peristalsis in patients with globus sensation and such defects are characterised with defective triggering of secondary peristalsis during rapid air distension. Whether current findings have therapeutic implication in the management of patients with globus sensation warrants further investigation.

Relevance of sleep disturbance to the integrity and characteristics of secondary peristalsis in patients with gastroesophageal reflux disease

OBJECTIVE

Sleep disturbance is common in patients with gastroesophageal reflux disease (GERD). Secondary peristalsis is important for clearance of the refluxate from the esophagus. We aimed to test the hypothesis whether secondary peristalsis is impaired in GERD patients with sleep disturbance.

METHODS

Secondary peristalsis was stimulated with slow and rapid air injections into mid-esophagus in 8 age-matched health controls and 41 patients with GERD. Sleep disturbance was assessed by the Pittsburg Sleep Quality Index (PSQI). Objective sleep measures were assessed by ambulatory actigraphy.

RESULTS

The threshold volume for inducing secondary peristalsis during slow air injection was significantly higher in GERD patients with sleep disturbance than healthy controls (14.3 ± 1.2 vs. 8.9 ± 0.5 mL, p < .05). GERD patients with sleep disturbance had higher threshold volume of secondary peristalsis during rapid air injection than GERD patients without sleep disturbance (5.1 ± 0.4 vs. 3.9 ± 0.2 mL, p < .05) and healthy controls (5.1 ± 0.4 vs. 3.6 ± 0.2 mL, p < .05). There was a negative correlation between PSQI score and peristaltic frequency during rapid air injection (r = -.39, p = .01). Secondary peristaltic amplitude during rapid air injection was negatively correlated with wake after sleep onset (r = -.34, p = .04).

CONCLUSIONS

Sleep disturbance is associated with secondary peristaltic response to distension-induced esophageal stimulation in patients with GERD. Our study suggests that sleep disturbance per se may adversely influence the effectiveness of esophageal peristalsis and bolus clearance during sleep in patients with GERD.

Influence of capsaicin infusion on secondary peristalsis in patients with gastroesophageal reflux disease

AIM

To determine whether capsaicin infusion could influence heartburn perception and secondary peristalsis in patients with gastroesophageal reflux disease (GERD).

METHODS

Secondary peristalsis was performed with slow and rapid mid-esophageal injections of air in 10 patients with GERD. In a first protocol, saline and capsaicin-containing red pepper sauce infusions were randomly performed, whereas 2 consecutive sessions of capsaicin-containing red pepper sauce infusions were performed in a second protocol. Tested solutions including 5 mL of red pepper sauce diluted with 15 mL of saline and 20 mL of 0.9% saline were infused into the mid-esophagus via the manometric catheter at a rate of 10 mL/min with a randomized and double-blind fashion. During each study protocol, perception of heartburn, threshold volumes and peristaltic parameters for secondary peristalsis were analyzed and compared between different stimuli.

RESULTS

Infusion of capsaicin significantly increased heartburn perception in patients with GERD (P < 0.001), whereas repeated capsaicin infusion significantly reduced heartburn perception (P = 0.003). Acute capsaicin infusion decreased threshold volume of secondary peristalsis (P = 0.001) and increased its frequency (P = 0.01) during rapid air injection. The prevalence of GERD patients with successive secondary peristalsis during slow air injection significantly increased after capsaicin infusion (P = 0.001). Repeated capsaicin infusion increased threshold volume of secondary peristalsis (P = 0.002) and reduced the frequency of secondary peristalsis (P = 0.02) during rapid air injection.

CONCLUSION

Acute esophageal exposure to capsaicin enhances heartburn sensation and promotes secondary peristalsis in gastroesophageal reflux disease, but repetitive capsaicin infusion reverses these effects.

Effects of prucalopride on esophageal secondary peristalsis in humans

Objectives:

Prucalopride, a high-affinity 5-hydroxytrypatamine 4 (5-HT₄) receptors agonist, has been shown to improve colon motility in adults. Secondary peristalsis helps the clearance of retained food bolus and refluxate from the esophagus, but the effects of prucalopride on esophageal secondary peristalsis are unknown. We aimed to assess the effects of prucalopride on distension-induced secondary peristalsis in healthy adults.

Methods:

Two separate sessions with prucalopride and placebo were performed in 11 healthy adults to test the effects on secondary peristalsis. Secondary peristalsis was performed with slow and rapid mid-esophageal injections of air after a baseline recording of esophageal motility.

Results:

Prucalopride significantly decreased the threshold volume to generate secondary peristalsis during slow air injection (9.8±1.4 vs. 14.4±0.9 ml, P=0.005) and rapid air injection (3.9±0.3 vs. 5.2±0.4 ml, P=0.008). Secondary peristalsis was generated more frequently after application of prucalopride (80% (70–100%) vs. 70% (60–73%), P=0.01). Prucalopride increased the wave amplitude of distal esophagus during slow air injection (147.9±28.5 vs. 104.2±16.8 mm Hg, P=0.048) and rapid air injection (128.0±13.3 vs. 105.7±12.3 mm Hg, P=0.016). Primary peristaltic amplitudes were also significantly increased by the application of prucalopride.

Conclusions:

Acute administration of prucalopride enhances mechanosensitivity of distension-induced secondary peristalsis and promotes esophageal contractility in healthy adults. Whether prucalopride could be a therapeutic option for the treatment of subjects with esophageal hypomotility needs further study.

Characterization and mechanisms of the pharyngeal swallow activated by stimulation of the esophagus

Stimulation of the esophagus activates the pharyngeal swallow response (EPSR) in human infants and animals. The aims of this study were to characterize the stimulus and response of the EPSR and to determine the function and mechanisms generating the EPSR. Studies were conducted in 46 decerebrate cats in which pharyngeal, laryngeal, and esophageal motility was monitored using EMG, strain gauges, or manometry. The esophagus was stimulated by balloon distension or luminal fluid infusion. We found that esophageal distension increased the chance of occurrence of the EPSR, but the delay was variable. The chance of occurrence of the EPSR was related to the position, magnitude, and length of the stimulus in the esophagus. The most effective stimulus was long, strong, and situated in the cervical esophagus. Acidification of the esophagus activated pharyngeal swallows and sensitized the receptors that activate the EPSR. The EPSR was blocked by local anesthesia applied to the esophageal lumen, and electrical stimulation of the recurrent laryngeal nerve caudal to the cricoid cartilage (RLNc) activated the pharyngeal swallow response. We conclude that the EPSR is activated in a probabilistic manner. The receptors mediating the EPSR are probably mucosal slowly adapting tension receptors. The sensory neural pathway includes the RLNc and superior laryngeal nerve. We hypothesize that, because the EPSR is observed in human infants and animals, but not human adults, activation of EPSR is related to the elevated position of the larynx. In this situation, the EPSR occurs rather than secondary peristalsis to prevent supraesophageal reflux when the esophageal bolus is in the proximal esophagus.

Differences in the Control of Secondary Peristalsis in the Human Esophagus: Influence of the 5-HT4 Receptor versus the TRPV1 Receptor

Objective

Acute administration of 5-hydroxytryptamine4 (5-HT₄) receptor agonist, mosapride or esophageal infusion of the transient receptor potential vanilloid receptor-1 (TRPV₁) agonist capsaicin promotes secondary peristalsis. We aimed to investigate whether acute esophageal instillation of capsaicin-containing red pepper sauce or administration of mosapride has different effects on the physiological characteristics of secondary peristalsis.

Methods

Secondary peristalsis was induced with mid-esophageal air injections in 14 healthy subjects. We compared the effects on secondary peristalsis subsequent to capsaicin-containing red pepper sauce (pure capsaicin, 0.84 mg) or 40 mg oral mosapride.

Results

The threshold volume for generating secondary peristalsis during slow air distensions was significantly decreased with capsaicin infusion compared to mosapride (11.6 ± 1.0 vs. 14.1 ± 0.8 mL, P = 0.02). The threshold volume required to produce secondary peristalsis during rapid air distension was also significantly decreased with capsaicin infusion (4.6 ± 0.5 vs. 5.2 ± 0.6 mL, P = 0.02). Secondary peristalsis was noted more frequently in response to rapid air distension after capsaicin infusion than mosapride (80% [60–100%] vs. 65% [5–100%], P = 0.04). Infusion of capsaicin or mosapride administration didn’t change any parameters of primary or secondary peristalsis.

Conclusions

Esophageal infusion with capsaicin-containing red pepper sauce suspension does create greater mechanosensitivity as measured by secondary peristalsis than 5-HT₄ receptor agonist mosapride. Capsaicin-sensitive afferents appear to be more involved in the sensory modulation of distension-induced secondary peristalsis.

Effects of esophageal capsaicin instillation on acid induced excitation of secondary peristalsis in humans

BACKGROUND/AIM

Esophageal instillation of capsaicin or hydrochloric acid enhances secondary peristalsis. Our aim was to investigate whether intra-esophageal capsaicin infusion can influence symptom perception and physiological alteration of secondary peristalsis subsequent to acid infusion.

METHODS

Secondary peristalsis was induced by mid-esophagus injections of air in 18 healthy subjects. Two different sessions including esophageal infusion of hydrochloric acid (0.1 N) following pretreatment with saline or capsaicin-containing red pepper sauce were randomly performed at least one week apart. Symptoms of heartburn and secondary peristalsis were determined and compared between each study session.

RESULTS

The intensity of heartburn symptom subsequent to acid infusion was significantly reduced after capsaicin infusion as compared with saline infusion (54 ± 3 vs 61 ± 3; P = 0.03). Capsaicin infusion significantly increased the threshold volume of secondary peristalsis to rapid air injections subsequent to esophageal acid infusion (8.0 ± 0.5 mL vs 4.4 ± 0.3 mL; P < 0.0001). The frequency of secondary peristalsis subsequent to acid infusion was significantly decreased after capsaicin infusion as compared to saline infusion (70% [60-82.5%] vs 80% [70-90%]; P = 0.03). Capsaicin infusion significantly decreased the pressure wave amplitude of secondary peristalsis subsequent to acid infusion during rapid air injections (90.6 ± 8.7 mmHg vs 111.1 ± 11.1 mmHg; P = 0.03).

CONCLUSIONS

Capsaicin appears to desensitize the esophagus to acid induced excitation of secondary peristalsis in humans, which is probably mediated by rapidly adapting mucosal mechanoreceptors. High capsaicin-containing diet might attenuate normal physiological response to abrupt acid reflux by inhibiting secondary peristalsis.

Effects of aging and acid reflux on esophageal motility

BACKGROUNDS

It is generally thought that esophageal motility decreases with age; however, a decrease in esophageal motility may also be caused by esophagitis. The aim of this study is to investigate the effects of aging and acid reflux on esophageal motility.

METHODS

40 young (under 45) healthy subjects (HS), 40 elderly (over 65) HS, and 40 elderly (over 65) patients with mild reflux esophagitis (RE), underwent esophageal high-resolution manometry (HRM). Lower esophageal sphincter pressure (LESP), primary peristalsis (PP), and secondary peristalsis (SP) were evaluated.

RESULTS

There was no difference in the LESP and also in the success rate of PP between young and elderly HS or between elderly HS and RE. There was no difference in the distal contractile integral (DCI) of PP and SP between the young and elderly HS, but in the elderly RE, it was significantly lower than in the elderly HS. There was no difference in the success rate of SP between elderly HS and RE, but in elderly HS it was significantly lower than in young HS.

CONCLUSIONS

Aging may cause a decrease in the success rate of SP, and acid reflux itself may cause a decrease of the DCI in PP and SP.

Utilizing functional lumen imaging probe topography to evaluate esophageal contractility during volumetric distention: a pilot study

BACKGROUND

The functional lumen imaging probe (FLIP) measures luminal cross-sectional area and pressure during volumetric distension. By applying novel customized software to produce FLIP topography plots, organized esophageal contractility can be visualized and analyzed. We aimed to describe the stimulus thresholds and contractile characteristics for distension-induced esophageal body contractility using FLIP topography in normal controls.

METHODS

Ten healthy controls were evaluated during endoscopy with FLIP. During stepwise bag distension, simultaneous intra-bag pressure and luminal diameter measurements were obtained and exported to a MatLab program to generate FLIP topography plots. The distension volume, intra-bag pressure, and maximum esophageal body diameters were measured for the onset and cessation of repetitive antegrade contractions (RACs). Contraction duration, interval, magnitude, and velocity were measured at 8 and 3-cm proximal to the esophagogastric junction.

KEY RESULTS

Eight of ten subjects demonstrated RACs at a median onset volume of 29 mL (IQR: 25-38.8), median intra-bag pressure of 10.7 mmHg (IQR: 8.6-15.9), and median maximum esophageal body diameter of 18.5 mm (IQR: 17.5-19.6). Cessation of RACs occurred prior to completion of the distension protocol in three of the eight subjects exhibiting RACs. Values of the RAC-associated contractile metrics were also generated to characterize these events.

CONCLUSIONS & INFERENCES

Distension-induced esophageal contractions can be assessed utilizing FLIP topography. RACs are a common finding in asymptomatic controls in response to volume distention and have similar characteristics to secondary peristalsis and repetitive rapid swallows.

Influence of repeated infusion of capsaicin-contained red pepper sauce on esophageal secondary peristalsis in humans

BACKGROUND

The transient receptor potential vanilloid 1 has been implicated as a target mediator for heartburn perception and modulation of esophageal secondary peristalsis. Our aim was to determine the effect of repeated esophageal infusion of capsaicin-contained red pepper sauce on heartburn perception and secondary peristalsis in healthy adults.

METHODS

Secondary peristalsis was performed with mid-esophageal injections of air in 15 healthy adults. Two separate protocols including esophageal infusion with saline and capsaicin-contained red pepper sauce and 2 consecutive sessions of capsaicin-contained red pepper sauce were randomly performed.

KEY RESULTS

After repeated infusion of capsaicin-contained red pepper sauce, the threshold volume to activate secondary peristalsis was significantly increased during slow (p < 0.001) and rapid air injections (p = 0.004). Acute infusion of capsaicin-contained red pepper sauce enhanced heartburn perception (p < 0.001), but the intensity of heartburn perception was significantly reduced after repeated capsaicin-contained red pepper sauce infusion (p = 0.007). Acute infusion of capsaicin-contained red pepper sauce significantly increased pressure wave amplitudes of distal esophagus during slow (p = 0.003) and rapid air injections (p = 0.01), but repeated infusion of capsaicin-contained red pepper sauce significantly decreased pressure wave amplitude of distal esophagus during slow (p = 0.0005) and rapid air injections (p = 0.003).

CONCLUSIONS & INFERENCES

Repeated esophageal infusion of capsaicin appears to attenuate heartburn perception and inhibit distension-induced secondary peristalsis in healthy adults. These results suggest capsaicin-sensitive afferents in modulating sensorimotor function of secondary peristalsis in human esophagus.

Quantitative differences between primary and secondary peristaltic contractions of the esophagus

BACKGROUND AND AIMS

Differences in contraction characteristics between primary and secondary peristalsis have only been scarcely studied. Recently new measures of contractile activity in the human esophagus were developed. The study aims were to use combined manometry and impedance planimetry [pressure-cross-sectional area (P-CSA)] recordings from healthy volunteers to examine esophageal peristalsis, and, furthermore, to investigate the effect of the motility enhancing drug erythromycin to study differential effects on the two types of contractions.

METHODS

Sixteen healthy volunteers participated in the study [mean age 23 (range, 19-34) years, 6 females]. An esophageal probe with a bag for CSA measurement was positioned 10 cm above the lower esophageal sphincter. Bag volume was increased stepwise from 5 to 25 ml before and after intravenous infusion of 250 mg erythromycin. Swallow-evoked primary and distension-evoked secondary esophageal peristalsis were compared with regard to (1) pressure amplitude, (2) CSA amplitude, (3) preload tension (wall tension before an evoked contraction), (4) contractile tension, and (5) work outputs.

RESULTS

Primary peristalsis induced more efficient contractions as the contraction amplitudes, work output and contractile tension were higher compared to secondary peristalsis (P < 0.001). Erythromycin induced change in CSA during distension-evoked secondary peristalsis (CSA before 212.9 ± 26.8 vs. after 180.5 ± 23.3, P < 0.05). The sensitivity to esophageal distension increased with the distending volume both before and during erythromycin. The sensitivity was not changed by erythromycin (P = 0.6).

CONCLUSIONS

Esophageal primary peristaltic contractions were more forceful with longer duration, and higher work output compared to secondary peristalsis contractions. Erythromycin affected peristalsis only to a minor degree.

Rapid air infusion into the oesophagus: Motor response in patients with achalasia and nonobstructive dysphagia assessed with high-resolution manometry

BACKGROUND

Achalasia is a neurodegenerative disorder of the oesophagus. Alteration of motor activity induced by oesophageal distension has not been explored.

OBJECTIVES

To investigate this function, using high-resolution Manometry.

METHODS

This study enrolled 15 healthy subjects, 15 nonobstructive dysphagia (NOD), and 18 achalasia patients successfully treated with pneumatic dilation (six with restored peristalsis). The three groups underwent five rapid (<1 s) intraoesophageal infusions of 20-ml air boluses, followed by eight 5-ml water swallows.

RESULTS

WHEREAS THE RESPONSE RATE TO WATER SWALLOWS WAS SIMILAR IN THE THREE GROUPS, AIR INFUSION INDUCED A LOWER RESPONSE RATE IN ACHALASIA (MEDIAN, INTERQUARTILE RANGE: 70%, 40-100%) and, to a lesser extent, in NOD patients (100%, 60-100%) than in healthy subjects (100%, 100-100%; p < 0.001 and p = 0.06, respectively). However, the response rate was highly variable in achalasia patients irrespective of presence of peristalsis. Furthermore, the strength of motor response to air infusion when compared to water swallows was diminished in achalasia patients but not in healthy subjects and NOD.

CONCLUSIONS

Motor response to rapid air infusion was variably impaired in achalasia. The role of this alteration in the long-term outcome deserves evaluation.

Role of peripheral reflexes in the initiation of the esophageal phase of swallowing

The aim of this study was to determine the role of peripheral reflexes in initiation of the esophageal phase of swallowing. In 10 decerebrate cats, we recorded electromyographic responses from the pharynx, larynx, and esophagus and manometric data from the esophagus. Water (1-5 ml) was injected into the nasopharynx to stimulate swallowing, and the timing of the pharyngeal and esophageal phases of swallowing was quantified. The effects of transection or stimulation of nerves innervating the esophagus on swallowing and esophageal motility were tested. We found that the percent occurrence of the esophageal phase was significantly related to the bolus size. While the time delays between the pharyngeal and esophageal phases of swallowing were not related to the bolus size, they were significantly more variable than the time delays between activation of muscles within the pharyngeal phase. Transection of the sensory innervation of the proximal cervical esophagus blocked or significantly inhibited activation of the esophageal phase in the proximal cervical esophagus. Peripheral electrical stimulation of the pharyngoesophageal nerve activated the proximal cervical esophagus, peripheral electrical stimulation of the vagus nerve activated the distal cervical esophagus, and peripheral electrical stimulation the superior laryngeal nerve (SLN) had no effect on the esophagus. Centripetal electrical stimulation of the SLN activated the cervical component of the esophageal phase of swallowing before initiation of the pharyngeal phase. Therefore, we concluded that initiation of the esophageal phase of swallowing depends on feedback from peripheral reflexes acting through the SLN, rather than a central program.

Relevance of ineffective esophageal motility to secondary peristalsis in patients with gastroesophageal reflux disease

BACKGROUND AND AIMS

The study aimed to investigate the hypothesis whether the presence of Ineffective esophageal motility would affect physiological characteristics of secondary peristalsis.

METHODS

Secondary peristalsis was performed with slow and rapid air injections into mid-esophagus of 18 ineffective esophageal motility patients and 15 age-matched controls. Severity of ineffective esophageal motility was defined by the application of combined multichannel intraluminal impedance and manometry.

RESULTS

Ineffective esophageal motility patients included 11 patients without impedance abnormality and seven patients with impedance abnormality during liquid and/or viscous swallowing. The prevalence of failed secondary peristaltic response during slow air injection was significantly greater in ineffective esophageal motility patients without impedance abnormality (3/11 [27%], P < 0.001) and with impedance abnormality (4/7 [57%], P = 0.04) than healthy subjects. The threshold volume for inducing secondary peristalsis during rapid air injection was significantly greater in ineffective esophageal motility patients with impedance abnormality (6.1 ± 0.3 mL) than healthy subjects (4.6 ± 0.3 mL, P < 0.05) and ineffective esophageal motility patients without impedance abnormality (4.1 ± 0.4 mL, P < 0.05). The frequency of peristaltic response during rapid air injection was significantly lower in ineffective esophageal motility patients with impedance abnormality (40% [20-50%] than healthy subjects (90% [90-100%], P < 0.05).

CONCLUSIONS

Defective activation of secondary peristalsis is present in ineffective esophageal motility patients with impedance abnormality. Our study indicates that increased ineffective esophageal motility severity associated with defective triggering of secondary peristalsis may contribute to impaired esophageal clearance in patients with gastroesophageal reflux disease.

Effects of mosapride on secondary peristalsis in patients with ineffective esophageal motility

OBJECTIVE. Ineffective esophageal motility is frequently found in patients with gastroesophageal reflux diseases. Secondary peristalsis contributes to esophageal acid clearance. Mosapride improves gastrointestinal (GI) motility by acting on 5-hydroxytrypatamine4 receptors. The authors aimed to evaluate the effect of mosapride on secondary peristalsis in patients with ineffective esophageal motility. MATERIAL AND METHODS. After recording primary peristalsis baseline, secondary peristalsis was stimulated by slowly and rapidly injecting mid-esophageal air in 18 patients. Two separate experiments were randomly performed with 40 mg oral mosapride or placebo. RESULTS. Mosapride had no effect on the threshold volume of secondary peristalsis during slow air distension (9.8 ± 0.97 vs. 10.2 ± 1.0 mL; p = 0.84), but decreased the threshold volume during rapid air distension (4.1 ± 0.2 vs. 4.6 ± 0.3 mL; p = 0.001). The efficiency of secondary peristalsis during rapid air distension increased with mosapride (70% [40-95%]) compared with placebo (60% [10-85%]; p = 0.0003). Mosapride had no effect on the amplitudes of distal pressure wave of secondary peristalsis during slow (94.3 ± 9 vs. 101.9 ± 9.1 mmHg; p = 0.63) or rapid air distension (89.3 ± 9 vs. 95.2 ± 8.3 mmHg; p = 0.24). CONCLUSIONS. Mosapride improves esophageal sensitivity of secondary peristalsis by abrupt air distension but has limited effect on the motor properties of secondary peristalsis in ineffective esophageal motility patients. Despite its well-known prokinetic effect, mosapride enhances the efficiency of secondary peristalsis in patients with ineffective esophageal motility through augmenting esophageal sensitivity instead of motility.

Comparable effects of capsaicin-containing red pepper sauce and hydrochloric acid on secondary peristalsis in humans

BACKGROUND AND AIM

We aimed to evaluate whether acute esophageal instillation of capsaicin and hydrochloric acid had different effects on distension-induced secondary peristalsis.

METHODS

Secondary peristalsis was induced by slow and rapid air injections into the mid-esophagus after the evaluation of baseline motility in 16 healthy subjects. The effects on secondary peristalsis were determined by esophageal instillation with capsaicin-containing red pepper sauce (pure capsaicin, 0.84 mg) and hydrochloric acid (0.1 N).

RESULTS

The administration of capsaicin induced a significant increase in the visual analogue scale score for heartburn as compared with hydrochloric acid (P = 0.002). The threshold volume for generating secondary peristalsis during slow and rapid air distensions did not differ between capsaicin and hydrochloric acid infusions. Hydrochloric acid significantly increased the frequency of secondary peristalsis in response to rapid air distension compared with capsaicin infusion (P = 0.03). Pressure wave amplitude during slow air distension was greater with the infusion of hydrochloric acid than capsaicin infusion (P = 0.001). The pressure wave duration during rapid air distension was longer after capsaicin infusion than hydrochloric acid infusion (P = 0.01). The pressure wave amplitude during rapid air distension was similar between capsaicin and hydrochloric acid infusions.

CONCLUSIONS

Despite subtle differences in physiological characteristics of secondary peristalsis, acute esophageal instillation of capsaicin and hydrochloric acid produced comparable effects on distension-induced secondary peristalsis. Our data suggest the coexistence of both acid- and capsaicin-sensitive afferents in human esophagus which produce similar physiological alterations in secondary peristalsis.

Influence of intraluminal acidification on esophageal secondary peristalsis in humans

BACKGROUND

Secondary peristalsis contributes to clearance of retained refluxate or material from the esophagus.

AIM

The goal of our study was to investigate the effects of hydrochloric acid (HCl) on physiological characteristics of esophageal secondary peristalsis in healthy adults.

METHODS

After recording esophageal motility baseline for primary peristalsis, secondary peristalsis was stimulated with slow and rapid air injections in the mid-esophageal in 16 healthy subjects. Normal saline and HCl (0.1 N) were separately infused into the esophagus to test whether they had effects on secondary peristalsis.

RESULTS

After infusion of HCl, the threshold volume to generate secondary peristalsis was significantly decreased during rapid and slow air infusions (both P < 0.05). The frequency of secondary peristalsis was increased after HCl infusion (90 % [72.5-100 %] versus 85 % [72.5-90 %], P = 0.002). Infusion of HCl significantly increased pressure wave amplitude during rapid and slow air infusions (both P < 0.05). Infusion of saline did not affect any parameters of secondary peristalsis. The occurrence of heartburn was generated in 7 of 16 subjects after infusion of HCl with an increase in visual analogue scale score (12.5).

CONCLUSIONS

Our data show that acute esophageal acid infusion enhances sensitivity of distension-induced secondary peristalsis and enhances secondary peristaltic activity. The study supports the evidence of the presence of acid-sensitive afferents in the modulation of distension-induced secondary peristalsis in humans.

Symptoms of aerophagia are common in patients on continuous positive airway pressure therapy and are related to the presence of nighttime gastroesophageal reflux

STUDY OBJECTIVES

Continuous positive airway pressure (CPAP), the mainstay treatment for obstructive sleep apnea (OSA), involves administration of air under pressure to the upper airway. A well-known but poorly understood side effect of positive airway pressure therapies is aerophagia, air entering the esophagus and stomach rather than the lungs. Gastric distension, a consequence of aerophagia, can increase gastroesophageal reflux (GER) by increasing transient lower esophageal sphincter relaxations, the most common cause of reflux. This study aimed to determine: (i) the prevalence of aerophagia symptoms in a group of OSA patients on CPAP therapy, and (ii) whether aerophagia symptoms are related to an increase in prevalence of GER symptoms.

METHODS

Consecutive OSA patients undergoing polysomnography for the purpose of optimizing their CPAP therapy completed a validated questionnaire regarding GER symptoms and aerophagia symptoms. Complete datasets were collected for 259 individuals (203 males).

RESULTS

The group with aerophagia symptoms (n = 130) had a greater prevalence of frequent (≥ once a week) GER symptoms (29% vs. 10%, p < 0.05) and nighttime GER symptoms (9 vs. 2%, p < 0.05) than those without aerophagia (n = 129). The group with nighttime GER symptoms (n = 27) had a greater prevalence of aerophagia symptoms (63% vs. 23%, p < 0.05) than those without nighttime GER symptoms (n = 232).

CONCLUSIONS

In patients with OSA being treated with CPAP, the prevalence of GER and nighttime GER symptoms is greater in those with symptoms of aerophagia than those without. CPAP-induced aerophagia might precipitate GER, particularly nighttime GER, by exacerbating transient lower esophageal relaxations through gastric distension.

Effects of mosapride on esophageal secondary peristalsis in humans

BACKGROUND

Secondary peristalsis is important for the clearance of refluxate or retained food bolus from the esophagus. Mosapride is a prokinetic agent that enhances GI motility by stimulating 5-hydroxytrypatamine(4) (5-HT(4) ) receptors, but its effects on secondary peristalsis are yet unclear in humans. We aimed to investigate the effect of a 5-HT(4) agonist mosapride on esophageal distension-induced secondary peristalsis in normal subjects.

METHODS

After a baseline recording esophageal motility, secondary peristalsis was generated by slow and rapid mid-esophageal injections of air in 15 healthy subjects. Two separate sessions with 40mg oral mosapride or placebo were randomly performed to test their effects on esophageal secondary peristalsis.

KEY RESULTS

Mosapride decreased the threshold volume for triggering secondary peristalsis during rapid air distension (4.5±0.3 vs 5.3±0.4mL; P=0.04) but not slow air distension (14.3±1.2 vs 13.3±1.3mL; P=0.41). Secondary peristalsis was triggered more frequently in response to rapid air distension after application of mosapride [100% (90-100%) vs 90% (80-100%); P=0.02]. Mosapride significantly increased pressure wave amplitudes of secondary peristalsis during slow (135.4±13.8 vs 105.0±12.9mmHg; P=0.001) and rapid air distensions (124.0±11.6 vs 95.9±14.0mmHg; P=0.002).

CONCLUSIONS & INFERENCES

Mosapride enhances sensitivity to distension-induced secondary peristalsis and facilitates secondary peristaltic contractility. These data provide an evidence for modulation of esophageal secondary peristalsis by the 5-HT(4) agonist mosapride, as well support for its clinical utility.

Control of esophageal distension-induced secondary peristalsis by the GABA(B) agonist baclofen in humans

BACKGROUND

Secondary peristalsis is important for the clearance of retained food bolus or refluxate from the esophagus. The effects of the gamma aminobutyric acid receptor type B (GABA(B) ) agonist on secondary peristalsis remain unclear in humans. We aimed to investigate the effect of a GABA(B) agonist baclofen on esophageal secondary peristalsis.

METHODS

After a baseline recording of esophageal motility, secondary peristalsis was generated by slow and rapid mid-esophageal injections of air in 15 healthy subjects. Two separate sessions with 40mg oral baclofen or placebo were randomly performed to test their effects on secondary peristalsis.

KEY RESULTS

Baclofen increased the threshold volume for triggering secondary peristalsis during slow air distension (P=0.003) and rapid air distension (P=0.002). Baclofen reduced the rate of secondary peristalsis by rapid air distension from 90% to 30% (P=0.0002). Baclofen increased basal lower esophageal sphincter pressure (P=0.03). Baclofen did not affect any of peristaltic parameters during primary or secondary peristalsis.

CONCLUSIONS & INFERENCES

This study provides an evidence for inhibitory modulation of esophageal secondary peristalsis by the GABA(B) agonist baclofen. Activation of secondary peristalsis is probably modulated by GABA(B) receptors; however, baclofen does not lead to any motility change in secondary peristalsis.

Advancements in the analysis of esophageal pH monitoring in GERD

Ambulatory 24 h esophageal pH monitoring enables quantification of esophageal acid exposure and assessment of the temporal relationship between symptoms and acid reflux events. Analysis of pH monitoring is currently divided into upright and recumbent periods based on the patient's body position. However, in this Review, we demonstrate that physiologic studies have shown that sleep, and not recumbency, has a greater impact on gastroesophageal reflux during night-time. The physiologic studies are further supported by clinical trials demonstrating that gastroesophageal reflux characteristics during the recumbent-awake period are similar to those in the upright rather than the recumbent-asleep period. The introduction of the integrated pH monitoring and actigraphy data analysis program offers better separation of the recumbent-awake and recumbent-asleep periods. The physiologic studies and clinical trials, as well as the availability of a better tool to measure pH during sleep, support a paradigm shift in the analysis of pH monitoring data from body position (upright or recumbent) to state of consciousness (awake or asleep).

Effects of capsaicin-containing red pepper sauce suspension on esophageal secondary peristalsis in humans

BACKGROUND

Capsaicin-sensitive afferents have been implicated in the modulation of gastrointestinal sensorimotor functions. Secondary peristalsis is important for the clearance of retained refluxate or material from the esophagus. The aim of this study was to evaluate the effects of capsaicin-containing red pepper sauce suspension on esophageal secondary peristalsis in healthy adults.

METHODS

After a baseline recording of esophageal motility, secondary peristalsis was generated by slow and rapid mid-esophageal injections of air in 10 healthy subjects. Two separate sessions with saline and capsaicin-containing red pepper sauce were randomly performed to test their effects on esophageal secondary peristalsis.

KEY RESULTS

Infusion of capsaicin significantly increased pressure wave amplitude during rapid (P = 0.002) and slow air infusions (P = 0.01). After capsaicin, the threshold volume to generate secondary peristalsis was significantly decreased during rapid (P < 0.05) and slow air infusions (P = 0.02). Infusion of saline did not affect any parameters of secondary peristalsis during rapid or slow air infusion. The administration of capsaicin was accompanied by the occurrence of heartburn in all subjects.

CONCLUSIONS & INFERENCES

The acute administration of capsaicin-containing red pepper sauce suspension enhances sensitivity to distension-induced secondary peristalsis and facilitates secondary peristaltic contractility. These data suggest the involvement of capsaicin-sensitive afferents in the modulation of esophageal distension-induced secondary peristalsis in humans.

The effects of high-dose esomeprazole on gastric and oesophageal acid exposure and molecular markers in Barrett's oesophagus

BACKGROUND

Acid reflux is often difficult to control medically.

AIM

To assess the effect of 40 mg twice daily esomeprazole (high-dose) on gastric and oesophageal pH and symptoms, and biomarkers relevant to adenocarcinoma, in patients with Barrett's oesophagus (BO).

METHODS

Eighteen patients, treated with proton pump inhibitors as prescribed by their treating doctor, had their therapy increased to high-dose esomeprazole for 6 months.

RESULTS

At entry into the study, 9/18 patients had excessive 24-h oesophageal acid exposure, and gastric pH remained <4 for >16 h in 8/18. With high-dose esomeprazole, excessive acid exposure occurred in 2/18 patients, and gastric pH <4 was decreased from 38% of overall recording time and 53% of the nocturnal period to 15% and 17%, respectively (P < 0.001). There was a reduction in self-assessed symptoms of heartburn (P = 0.0005) and regurgitation (P < 0.0001), and inflammation and proliferation in the Barrett's mucosa. There was no significant change in p53, MGMT or COX-2 expression, or in aberrant DNA methylation.

CONCLUSIONS

High-dose esomeprazole achieved higher levels of gastric acid suppression and control of oesophageal acid reflux and symptoms, with significant decreases in inflammation and epithelial proliferation. There was no reversal of aberrant DNA methylation.

Effects of lidocaine on esophageal secondary peristalsis in humans

BACKGROUND

Secondary peristalsis is important for the clearance of retained food bolus or refluxate from the esophagus. Lidocaine has been used to evaluate the role of mucosa-mediating pathways of esophageal reflexes in animal model, but its effects on esophageal secondary peristalsis are yet unclear in humans. We aimed to investigate whether esophageal secondary peristalsis can be affected by intraluminal infusion of lidocaine into the esophagus.

METHODS

After a baseline recording esophageal motility, secondary peristalsis was generated by slow and rapid mid-esophageal injections of air in 13 healthy subjects. Two separate sessions with saline and lidocaine were randomly performed to test their effects on esophageal secondary peristalsis by mid-esophageal air distension.

KEY RESULTS

Secondary peristalsis can be induced by slow or rapid air infusion. Secondary peristalsis was triggered less frequently in response to rapid air distension after lidocaine infusion (P = 0.001). After lidocaine infusion, the threshold volume to generate secondary peristalsis was significantly increased during rapid (P = 0.001), but not slow air infusions (P = NS). Infusion of lidocaine or saline did not affect pressure wave amplitude or duration during rapid and slow air infusions (P = NS).

CONCLUSIONS & INFERENCES

We have demonstrated selectively inhibitory effect of lidocaine on the triggering of esophageal secondary peristalsis during acute gaseous esophageal distension. The data suggest that part of the activation of secondary peristalsis is probably mediated by lidocaine-sensitive mechanoreceptors; however, the infusion of lidocaine does not lead to any motility change in secondary peristalsis induced by either slow or rapid air infusions.

The prokinetic effect of mosapride citrate combined with omeprazole therapy improves clinical symptoms and gastric emptying in PPI-resistant NERD patients with delayed gastric emptying

BACKGROUND

Previous studies have shown that non-erosive reflux disease (NERD) patients are less sensitive to proton pump inhibitor (PPI) treatment than patients with erosive reflux disease. The aim of this study was to investigate whether treatment with prokinetics in addition to omeprazole therapy would improve clinical symptoms, gastric emptying and esophageal peristalsis in PPI-resistant NERD patients with or without delayed gastric emptying.

METHODS

Subjects were 64 consecutive patients presenting with typical symptoms of PPl-resistant NERD (n = 44) and 20 healthy volunteers. PPI-resistant NERD patients underwent mosapride citrate (15 mg/day) and omeprazole (20 mg/day) co-therapy for 12 weeks. We evaluated the clinical symptoms as well as gastric emptying and esophageal manometry before and after combined therapy. We measured both acylated- and des-acylated plasma ghrelin levels by the ELISA method. The primary endopoint was to investigate whether co-administration of mosapride citrate and omeprazole would improve clinical symptoms and gastric emptying in PPI-resistant NERD patients with delayed gastric emptying.

RESULTS

T (max) value in PPI-resistant NERD patients was significantly higher than in healthy volunteers. Combination therapy with the prokinetic agent mosapride citrate and omeprazole significantly improved reflux symptoms and T (max) value in T (max) > 65 min NERD patients. Co-therapy also significantly reduced des-acylated-ghrelin levels in NERD patients with delayed gastric emptying.

CONCLUSIONS

Administration of mosapride citrate in addition to omeprazole improved gastro-esophageal reflux and gastric emptying in PPI-resistant NERD patients with delayed gastric emptying.

Upregulation of the esophago-UES relaxation response: a possible pathophysiological mechanism in suspected reflux laryngitis

BACKGROUND

Inappropriate or excessive, non-swallow related, reflexive relaxation of the upper esophageal sphincter (UES) in response to esophageal distension may be the principal mechanism permitting retrograde trans-sphincteric flow during acid regurgitation. The neural pathways mediating reflexive UES relaxation in the human have received little attention. Patients with laryngitis demonstrate an increased acid reflux in the proximal esophagus. Such events, combined with an increased tendency for UES relaxation, might precipitate regurgitation into the pharynx. The aim was to determine whether the esophago-UES relaxation reflex induced by rapid esophageal distension is upregulated in patients with posterior laryngitis.

METHODS

In 21 healthy volunteers and 14 patients with posterior laryngitis, UES responses to rapid air insufflation were examined. UES responses were monitored with perfused manometry catheter with a oval sleeve sensor.

KEY RESULTS

The probability of triggering UES relaxation in response to the rapid esophageal air distension, for all volumes of insufflation, was higher in laryngitis (45%) than in health (17%). The minimum distension volume required to elicit an UES relaxation response was significantly lower in laryngitis patients when compared with controls. Patients who demonstrated a laryngoscopic response to a trial of omeprazole, were less likely to generate a distension-induced UES contractile response (5%) than patients who did not respond (23%).

CONCLUSIONS & INFERENCES

The threshold for esophageal distension-induced UES relaxation is reduced in patients with laryngitis when compared with controls. This finding supports the hypothesis that in this population, a hypersensitive belch-like response may be one contributory mechanism of regurgitation when triggered by an abrupt spontaneous gastro-esophageal reflux event.