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Objectives: To assess human in vivo intrarenal pressure (IRP) and peristaltic activity at baseline and after ureteric stent placement, using a narrow calibre pressure guidewire placed retrogradely in the renal pelvis., Patients and Methods: A prospective, multi-institutional study recruiting consenting patients undergoing ureteroscopy was designed with ethical approval. Prior to ureteroscopy, the urinary bladder was emptied and the COMET™ II pressure guidewire (Boston Scientific) was advanced retrogradely via the ureteric orifice to the renal pelvis. Baseline IRPs were recorded for 1-2 min. At procedure completion, following ureteric stent insertion, IRPs were recorded for another 1-2 min. Statistical analysis of mean baseline IRP, peristaltic waveforms and frequency of peristaltic contractions was performed, thereby analysing the influence of patient variables and ureteric stenting., Results: A total of 100 patients were included. Baseline mean (±SD) IRP was 16.76 (6.4) mmHg in the renal pelvis, with maximum peristaltic IRP peaks reaching a mean (SD) of 25.75 (17.9) mmHg. Peristaltic activity generally occurred in a rhythmic, coordinated fashion, with a mean (SD) interval of 5.63 (3.08) s between peaks. On univariate analysis, higher baseline IRP was observed with male sex, preoperative hydronephrosis, and preoperative ureteric stenting. On linear regression, male sex was no longer statistically significant, whilst the latter two variables remained significant (P = 0.004; P < 0.001). The mean (SD) baseline IRP in the non-hydronephrotic, unstented cohort was 14.19 (4.39) mmHg. Age, α-blockers and calcium channel blockers did not significantly influence IRP, and no measured variables influenced peristaltic activity. Immediately after ureteric stent insertion, IRP decreased (mean [SD] 15.18 [5.28] vs 16.76 [6.4] mmHg, P = 0.004), whilst peristaltic activity was maintained., Conclusions: Human in vivo mean (SD) baseline IRP is 14.19 (4.39) mmHg in normal kidneys and increases with both hydronephrosis and preoperative ureteric stenting. Mean (SD) peristaltic peak IRP values of 25.75 (17.9) mmHg are reached in the renal pelvis every 3-7 s and maintained in the early post-stent period., (© 2024 BJU International.)

Objective: To examine the biomarkers of pharyngoesophageal swallowing during oral feeding sessions in infants undergoing pH-impedance testing and determine whether swallow frequencies are distinct between oral-fed and partially oral-fed infants., Study Design: One oral feeding session was performed in 40 infants during pH-impedance studies and measurements included swallowing frequency, multiple swallow rate, air and liquid swallow rates, esophageal swallow clearance time, and gastroesophageal reflux (GER) characteristics. Linear and mixed statistical models were applied to examine the swallowing markers and outcomes., Results: Infants (30.2 ± 4.4 weeks' birth gestation) were evaluated at 41.2 ± 0.4 weeks' postmenstrual age. Overall, 10 675 swallows were analyzed during the oral feeding sessions (19.3 ± 5.4 minutes per infant) and GER events were noted (2.5 ± 0.3 per study). Twenty-four-hour acid reflux index (ARI) was 9.5 ± 2.0%. Differences were noted in oral-fed and partially oral-fed infants for volume consumption (P < .01), consumption rate (P < .01), and length of hospital stay in days (P < .01). Infants with ARI >7% had greater frequency of swallows (P = .01). The oral-fed group had greater ARI (12.7 ± 3.3%, P = .05)., Conclusions: Oropharyngeal swallowing regulatory characteristics decrease over the feeding duration and were different between ARI >7% vs ≤7%. Although GER is less in infants who are partially oral-fed, the neonates with increased acid exposure achieved greater oral intakes and shorter hospitalizations, despite the presence of comorbidities. Pharyngoesophageal stimulation as during consistent feeding or GER events can activate peristaltic responses and rhythms, which may be contributory to the findings., Competing Interests: Declaration of Competing Interest Supported by the Nationwide Foundation Endowed Chair in Neonatal Research Award (to S.J.). The authors have no conflicts of interest (financial, professional, or personal) to disclose., (Copyright © 2024 The Author(s). Published by Elsevier Inc. All rights reserved.)

The colonic peristaltic pressure signal is helpful for the diagnosis of intestinal diseases, but it is difficult to reflect the real situation of colonic peristalsis due to the interference of various factors. To solve this problem, an improved wavelet threshold denoising method based on discrete wavelet transform is proposed in this paper. This algorithm can effectively extract colonic peristaltic pressure signals and filter out noise. Firstly, a threshold function with three shape adjustment factors is constructed to give the function continuity and better flexibility. Then, a threshold calculation method based on different decomposition levels is designed. By adjusting the three preset shape factors, an appropriate threshold function is determined, and denoising of colonic pressure signals is achieved through hierarchical thresholding. In addition, the experimental analysis of bumps signal verifies that the proposed denoising method has good reliability and stability when dealing with non-stationary signals. Finally, the denoising performance of the proposed method was validated using colonic pressure signals. The experimental results indicate that, compared to other methods, this approach performs better in denoising and extracting colonic peristaltic pressure signals, aiding in further identification and treatment of colonic peristalsis disorders., (© 2024 IOP Publishing Ltd. All rights, including for text and data mining, AI training, and similar technologies, are reserved.)

Upon epithelial barrier dysfunction, lipopolysaccharide (LPS) stimulates glucagon-like peptide-1 (GLP-1) secretion from enteroendocrine L cells by activating Toll-like receptor 4 (TLR4). Because GLP-1 accelerates peristalsis in the proximal colon, the present study aimed to explore whether LPS facilitates colonic peristalsis by stimulating L cell-derived GLP-1 release. In isolated segments of rat proximal colon that were serosally perfused with physiological salt solution and luminally perfused with 0.9% saline, peristaltic wall motion was video recorded and converted into spatio-temporal maps. Fluorescence immunohistochemistry was also carried out. Intraluminal administration of LPS (100 or 1 µg mL -1 but not 100 ng mL -1 ) increased the frequency of oro-aboral propagating peristaltic contractions. The LPS-induced acceleration of colonic peristalsis was blocked by TAK-242 (the TLR4 antagonist), exendin-3 (the GLP-1 receptor antagonist) or BIBN4096 (the calcitonin gene-related peptide receptor antagonist). GLP-1-positive epithelial cells co-expressed TLR4 immunoreactivity. In aspirin-pretreated preparations where epithelial barrier function had been impaired, a lower dose of LPS (100 ng mL -1 ) became capable of accelerating peristalsis. By contrast, luminally applied dimethyl sulphoxide, a reactive oxygen species scavenger that protects epithelial integrity, attenuated the prokinetic effects of a higher dose of LPS (100 µg mL -1 ). In colonic segments of a stress rat model leading to a leaky gut, LPS induced more pronounced prokinetic effects. Colonic L cells may well sense luminal LPS via TLR4 triggering the release of GLP-1 that stimulates calcitonin gene-related peptide-containing neurons. The resultant acceleration of peristalsis would facilitate excretion of Gram-negative bacteria from the intestine, and thus L cells may have a protective role against intestinal bacterial infections. KEY POINTS: Colonic epithelial cells form a barrier against bacterial invasion but also may contribute more actively to the exclusion of luminal pathogen by stimulating colonic motility. Luminal lipopolysaccharide (LPS) accelerated colonic peristalsis by stimulating calcitonin gene-related peptide-containing neurons. The prokinetic effect of LPS was mediated by the secretion of glucagon-like peptide-1 from enteroendocrine L cells in which Toll-like receptor 4 was expressed. The LPS-mediated acceleration of peristalsis depended on epithelial barrier integrity. L cells have a defensive role against Gram-negative bacterial infections by facilitating faecal excretion, and could be a potential therapeutic target for gastrointestinal infections., (© 2024 The Authors. The Journal of Physiology © 2024 The Physiological Society.)

Background: Fontan procedure, the standard surgical palliation to treat children with single ventricular defects, causes systemic complications over years due to lack of pumping at cavopulmonary junction. A device developed specifically for cavopulmonary support is thus considered, while current commercial ventricular assist devices (VAD) induce high shear rates to blood, and have issues with paediatric suitability., Aim: To demonstrate the feasibility of a small, valveless, non-invasive to blood and pulsatile rotary pump, which integrates impedance and peristaltic effects., Methods: A prototype pump was designed and fabricated in-house without any effort to optimise its specification. It was then tested in vitro, in terms of effect of pumping frequency, background pressure differences and pump size on output performance., Results: Net flow rate (NFR) and maximum pressure head delivery are both reasonably linearly dependent on pumping frequency within normal physiological range. Positive linearity is also observed between NFR and the extent of asymmetric pumping. The device regulates NFR in favourable pressure head difference and overcomes significant adverse pressure head difference. Additionally, performance is shown to be insensitive to device size., Conclusions: The feasibility of the novel rotary pump integrating impedance and peristaltic effects is demonstrated to perform in normal physiological conditions without any optimisation effort. It provides promising results for possible future paediatric cavopulmonary support and warrants further investigation of miniaturisation and possible haemolysis., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

The gastrointestinal (GI) peristalsis is an involuntary wave-like contraction of the GI wall that helps to propagate food along the tract. Many GI diseases, e.g., gastroparesis, are known to cause motility disorders in which the physiological contractile patterns of the wall get disrupted. Therefore, to understand the pathophysiology of these diseases, it is necessary to understand the mechanism of GI motility. We present a coupled electromechanical model to describe the mechanism of GI motility and the transduction pathway of cellular electrical activities into mechanical deformation and the generation of intraluminal pressure (IP) waves in the GI tract. The proposed model consolidates a smooth muscle cell (SMC) model, an actin-myosin interaction model, a hyperelastic constitutive model, and a Windkessel model to construct a coupled model that can describe the origin of peristaltic contractions in the intestine. The key input to the model is external electrical stimuli, which are converted into mechanical contractile waves in the wall. The model recreated experimental observations efficiently and was able to establish a relationship between change in luminal volume and pressure with the compliance of the GI wall and the peripheral resistance to bolus flow. The proposed model will help us understand the GI tract's function in physiological and pathophysiological conditions., (© 2024. International Federation for Medical and Biological Engineering.)

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., (© 2024 The Author(s). The Kaohsiung Journal of Medical Sciences published by John Wiley & Sons Australia, Ltd on behalf of Kaohsiung Medical University.)

Background: Stomach, small intestine, and colon have distinct patterns of contraction related to their function to mix and propel enteric contents. In this study, we aim to measure gut myoelectric activity in the perioperative course using external patches in an animal model., Methods: Four external patches were placed on the abdominal skin of female Yucatan pigs to record gastrointestinal myoelectric signals for 3 to 5 d. Pigs subsequently underwent anesthesia and placement of internal electrodes on stomach, small intestine, and colon. Signals were collected by a wireless transmitter. Frequencies associated with peristalsis were analyzed for both systems for 6 d postoperatively., Results: In awake pigs, we found frequency peaks in several ranges, from 4 to 6.5 cycles per minute (CPM), 8 to 11 CPM, and 14 to 18 CPM, which were comparable between subjects and concordant between internal and external recordings. The possible effect of anesthesia during the 1 or 2 h before surgical manipulation was observed as a 59% (±36%) decrease in overall myoelectric activity compared to the immediate time before anesthesia. The myoelectrical activity recovered quickly postoperatively. Comparing the absolute postsurgery activity levels to the baseline for each pig revealed higher overall activity after surgery by a factor of 1.69 ± 0.3., Conclusions: External patch measurements correlated with internal electrode recordings. Anesthesia and surgery impacted gastrointestinal myoelectric activity. Recordings demonstrated a rebound phenomenon in myoelectric activity in the postoperative period. The ability to monitor gastrointestinal tract myoelectric activity noninvasively over multiple days could be a useful tool in diagnosing gastrointestinal motility disorders., (Copyright © 2024 Elsevier Inc. All rights reserved.)

Background and Objectives : The threshold for ineffective esophageal motility (IEM) diagnosis was changed in Chicago v4.0. Our aim was to determine IEM prevalence using the new criteria and the differences between patients with definite IEM versus "inconclusive diagnosis". Materials and Methods : We retrospectively selected IEM and fragmented peristalsis (FP) patients from the high-resolution esophageal manometries (HREMs) database. Clinical, demographic data and manometric parameters were recorded. Results : Of 348 HREMs analyzed using Chicago v3.0, 12.3% of patients had IEM and 0.86% had FP. Using Chicago v4.0, 8.9% of patients had IEM (IEM-4 group). We compared them with the remaining 16 with an inconclusive diagnosis of IEM (borderline group). Dysphagia (77% vs. 44%, Z-test = 2.3, p = 0.02) and weight loss were more commonly observed in IEM-4 compared to the borderline group. The reflux symptoms were more prevalent in the borderline group (87.5% vs. 70.9%, p = 0.2). Type 2 or 3 esophagogastric junction morphology was more prevalent in the borderline group (81.2%) vs. 64.5% in IEM-4 ( p = 0.23). Distal contractile integral (DCI) was lower in IEM-4 vs. the borderline group, and resting lower esophageal sphincter (LES) pressure and mean integrated relaxation pressure (IRP) were similar. The number of ineffective swallows and failed swallows was higher in IEM-4 compared to the borderline group. Conclusions : Using Chicago v4.0, less than 10% of patients had a definite diagnosis of IEM. The dominant symptom was dysphagia. Only DCI and the number of failed and inefficient swallows were different between definite IEM patients and borderline cases.

Our prior study reveals that the distension-contraction profiles using high-resolution manometry impedance recordings can distinguish patients with dysphagia symptom but normal esophageal function testing ("functional dysphagia") from control subjects. The aim of this study was to determine the diagnostic value of the recording protocol used in our prior studies (10-mL swallows with subjects in the Trendelenburg position) against the standard clinical protocol (5-mL swallows with subjects in the supine position). We used advanced machine learning techniques and robust metrics for classification purposes. Studies were performed on 30 healthy subjects and 30 patients with functional dysphagia. A custom-built software was used to extract the relevant distension-contraction features of esophageal peristalsis. Ensemble methods, i.e., gradient boost, support vector machines (SVMs), and logit boost, were used as the primary machine learning algorithms. Although the individual contraction features were marginally different between the two groups, the distension features of peristalsis were significantly different. The receiver operating characteristic (ROC) curve values for the standard recording protocol and the distension features ranged from 0.74 to 0.82; they were significantly better for the protocol used in our prior studies, ranging from 0.81 to 0.91. The ROC curve values using three machine learning algorithms were far superior for the distension than the contraction features of esophageal peristalsis, revealing a value of 0.95 for the SVM algorithm. Current patient classification for esophageal motility disorders, based on the contraction phase of peristalsis, ignores a large number of patients who have an abnormality in the distension phase of peristalsis. Distension-contraction plots should be the standard for assessing esophageal peristalsis in clinical practice. NEW & NOTEWORTHY Our findings underscore the superiority of distension features over contraction metrics in diagnosing esophageal dysfunctions. By leveraging state-of-the-art machine learning techniques, our study highlights the diagnostic potential of distension-contraction plots of peristalsis. Implementation of these plots could significantly enhance the accuracy of identifying patients with esophageal motor disorders, advocating for their adoption as the standard in clinical practice.

The stomach's ability to store, mix, propel, and empty its content requires highly coordinated motor functions. However, current diagnostic tools cannot simultaneously assess these motor processes. This study aimed to use magnetic resonance imaging (MRI) to map multifaceted gastric motor functions, including accommodation, tonic and peristaltic contractions, and emptying, through a single noninvasive experiment for both humans and rats. Ten humans and 10 Sprague-Dawley rats consumed MRI-visible semisolid meals and underwent MRI scans. We used a surface model to analyze MRI data, capturing the deformation of the stomach wall on ingestion or during digestion. We inferred muscle activity, mapped motor processes, parcellated the stomach into functional regions, and revealed cross-species distinctions. In humans, both the fundus and antrum distended postmeal, followed by sustained tonic contractions to regulate intragastric pressure. Peristaltic contractions initiated from the distal fundus, including three concurrent wavefronts oscillating at 3.3 cycles/min and traveling at 1.7 to 2.9 mm/s. These motor functions facilitated linear gastric emptying with a 61-min half-time. In contrast, rats exhibited peristalsis from the midcorpus, showing two wavefronts oscillating at 5.0 cycles/min and traveling at 0.4 to 0.9 mm/s. For both species, motility features allowed functional parcellation of the stomach along a midcorpus division. This study maps region- and species-specific gastric motor functions. We demonstrate the value of MRI with surface modeling in understanding gastric physiology and its potential to become a new standard for clinical and preclinical investigations of gastric disorders at both individual and group levels. NEW & NOTEWORTHY A novel MRI technique can visualize how the stomach accommodates, mixes, and propels food for digestion in humans and animals alike. Digital models of gastric MRI reveal the functional maps, organization, and distinction of the stomach across individuals and species. This technique holds the unique potential to advance basic and clinical studies of functional gastric disorders.

Background and Aims: Analysis of mean nocturnal baseline impedance (MNBI) and post-reflux swallow-induced peristaltic wave index (PSPWi) have been proposed to increase the diagnostic yield of pH-impedance studies in reflux disease. However, routine use of these indices in clinical studies is yet to be established, particularly with PSPWi, which requires laborious manual analysis. Our study aimed to assess the utility of MNBI and PSPWi and their potential for future incorporation into clinical practice., Methods: pH-impedance recordings from consecutive patients referred to the Motility Laboratory at Royal Adelaide Hospital for evaluation of gastro-oesophageal reflux disease (GORD) were prospectively collected and manually analysed. Baseline demographic characteristics, symptoms, acid exposure time (AET), number of reflux episodes, and MNBI and PSPWi were collected., Results: Eighty-nine patients were included in the study (age 50 ± 17 years, 35 males). MNBI and PSPWi inversely correlated with AET (R = -0.678, P < 0.0001 and R = -0.460, P < 0.0001 respectively) and with reflux episodes (R = -0.391, P = 0.0002 and R = -0.305, P = 0.0037 respectively). In patients with a negative pH study, but with typical reflux symptoms, 4/30 (13%) had pathologic MNBI and PSPWi. There was a positive correlation between MNBI and PSPWi values (R = 0.525, P < 0.0001). Performing analysis of PSPWi was substantially more laborious than MNBI., Conclusion: MNBI and PSPWi are both useful adjuncts in the diagnosis of reflux disease, although in our cohort MNBI showed stronger correlation with AET with less time to analyse. The role of these indices remains to be further explored, particularly in patients with inconclusive AET and in those with positive compared to negative symptom association., (© 2024 Royal Australasian College of Physicians.)

Background: Disorders of primary peristalsis are associated with a higher percent time pH <4 in the esophagus suggesting poor acid clearance. However, there are no studies of secondary peristalsis and its relationship to microscopic or erosive esophagitis. The goal of this study was to determine the relationship between secondary peristalsis using functional luminal imaging probes (EndoFLIP) and the presence or absence of esophagitis., Methods: We reviewed the endoscopic and EndoFLIP 2.0 tracings for 103 consecutive patients including those with a history of upper gastrointestinal surgery undergoing upper endoscopy. Esophagogastric junction (EGJ) distensibility and diameter, repetitive antegrade contraction (RACs) presence and frequency, and occlusive diameters were measured. Measurements were then compared between patients with and without microscopic and/or erosive esophagitis. Means were compared using t-tests. Proportions were compared using Chi-Squared analyses., Key Results: One hundred and three patients were included (mean age: 14.4 + 6.4 years). Ten patients had erosive esophagitis and 28 patients had microscopic esophagitis. Erosive and microscopic esophagitis were associated with abnormal or absent of RACs (p < 0.001). Occlusive diameters were higher in patients with esophagitis compared to those without (p < 0.001). There was no relationship between EGJ distensibility and the presence of erosive or microscopic esophagitis (p = 0.4). The absence of RACs was the only independent predictor of esophagitis (erosive and microscopic), after controlling for age, proton pump inhibitors (PPI) use and EGJ distensibility (p < 0.001)., Conclusions & Inferences: Abnormal secondary peristalsis is associated with microscopic and gross esophagitis, suggesting that EndoFLIP should be part of the diagnostic algorithm for esophagitis., (© 2024 John Wiley & Sons Ltd.)

Background: Capsaicin-containing red pepper sauce suspension augments esophageal contraction amplitude on conventional manometry. This study used high-resolution manometry (HRM) to investigate if capsaicin infusion modulates segmental esophageal smooth muscle peristalsis in healthy adults., Methods: Sixteen healthy volunteers (mean age 37 years, 14 male) underwent HRM for the evaluation of primary peristalsis and secondary peristalsis using slow and rapid air distensions. Both primary and secondary peristalsis were assessed following infusions of capsaicin-containing red pepper sauce and saline., Key Results: Capsaicin infusion significantly increased heartburn symptoms compared to saline infusion (p < 0.001), and significantly decreased threshold volumes of secondary peristalsis during rapid air distensions (p = 0.02). The frequency of secondary peristalsis during rapid air distensions was significantly increased by capsaicin infusion (p = 0.03). Neither capsaicin infusion (p = 0.06) nor saline infusion (p = 0.27) altered threshold volume during slow air distensions. Capsaicin infusion significantly increased distal contractile integral (DCI) of primary peristalsis (p = 0.04), particularly in the proximal smooth muscle segment (p = 0.048). It enhanced secondary peristalsis during rapid air distensions (p = 0.003) but not during slow air distension (p = 0.23). Saline infusion significantly increased DCI of secondary peristalsis during rapid air distension (p = 0.01)., Conclusions and Inferences: Augmentation of distension-induced secondary peristalsis can be modulated by activation of capsaicin-sensitive afferents similar to mechanosensitive afferents. Capsaicin-induced augmentation of primary peristalsis isolates to the cholinergic-mediated proximal smooth muscle segment, which warrants study in ineffective esophageal motility to determine therapeutic potential., (© 2024 John Wiley & Sons Ltd.)

Background: Understanding the relationship between distal contractile integral (DCI) and mean nocturnal baseline impedance (MNBI) could shed light on new diagnostic and treatment strategies, specifically concerning nocturnal reflux. This study aimed to assess this relationship to enhance our comprehension of the interplay between esophageal contractility and mucosal permeability., Methods: We identified adult patients who had high resolution esophageal manometry and pH-impedance tests performed within a 30-day period between December 2018 and March 2022. A random forest model was used to identify significant predictors of MNBI, assisting with variable selection for a following regression analysis. Subsequently, both univariable and multivariable regression models were utilized to measure the association between predictors and MNBI., Key Results: Our study included 188 patients, primarily referred for testing due to reflux. The most common motility diagnoses were normal (62%) followed by possible esophagogastric junction outflow obstruction (22%). The mean DCI was 2020 mmHg∙s∙cm and MNBI was 3.05 kΩ. The random forest model identified 12 significant predictors for MNBI, key variables being acid exposure time (AET), total proximal reflux events, intraabdominal lower esophageal sphincter length, hiatal hernia presence, and DCI. Subsequent multivariable regression analyses demonstrated log AET (β = -0.69, p = <0.001), total proximal reflux events (β = -0.16, p = 0.008), hiatal hernia presence (β = -0.82, p = 0.014), log DCI (β = 1.26, p < 0.001), and age (β = -0.13, p = 0.036) as being significantly associated with MNBI., Conclusions and Inferences: DCI is a key manometric predictor of MNBI emphasizing the role of manometry in detecting reflux risk and the need for its consideration in reflux management., (© 2024 John Wiley & Sons Ltd.)

Background: The functional relationship of striated esophagus (St.Eso) motor function with pharyngeal deglutitive biomechanical events has not been systematically studied. The aim of this study was to determine the spatio-temporal characteristics of St.Eso function and its correlation with pharyngeal biomechanics and bolus transport., Methods: We studied 50 healthy volunteer subjects (age range: 21-82 years, 31 female) by digital videofluoroscopy. All subjects were studied in a seated, upright position. Thirteen of these 50 volunteers also underwent high-resolution manometry (HRM) concurrent with fluoroscopy. We used laryngeal excursion as a surrogate for St.Eso excursion., Key Results: Median duration of St.Eso excursion was 2.35 [1.93,2.85, 5th and 95th percentile] seconds. Mean maximum extent of St.Eso excursion was 2.84 ± 0.72 cm. We identified four distinct periods in deglutitive St.Eso motor function: P1. Anterosuperior ascent without bolus or peristaltic activity, P2. Non-peristaltic bolus receiving at the apogee of St.Eso excursion concurrent with UES opening and pharyngeal peristalsis P3. Peristaltic bolus transport as St.Eso descends and P4. Continued peristalsis in resting position., Conclusions and Inferences: 1. St.Eso motor function spans both pharyngeal and esophageal phases of swallowing for receiving and transporting the bolus, 2. Pressure signatures in HRM recordings currently attributed to St.Eso deglutitive motor activity does not represent the entirety of St.Eso peristalsis, only the part that occurs in its resting position. St.Eso peristalsis that occurs during its descent is recorded by pressure sensors initially in the pharynx. This finding needs to be considered when interpreting HRM recordings of the pharynx and proximal esophagus., (© 2024 John Wiley & Sons Ltd.)

Gastric peristalsis is governed by electrical "slow waves" generally assumed to travel from proximal to distal stomach (antegrade propagation) in symmetric rings. Although alternative slow-wave patterns have been correlated with gastric disorders, their mechanisms and how they alter contractions remain understudied. Optical electromechanical mapping, a developing field in cardiac electrophysiology, images electrical and mechanical physiology simultaneously. Here, we translate this technology to the in vivo porcine stomach. Stomachs were surgically exposed and a fluorescent dye (di-4-ANEQ(F)PTEA) that transduces the membrane potential ( V m ) was injected through the right gastroepiploic artery. Fluorescence was excited by LEDs and imaged with one or two 256 × 256 pixel cameras. Motion artifact was corrected using a marker-based motion-tracking method and excitation ratiometry, which cancels common-mode artifact. Tracking marker displacement also enabled gastric deformation to be measured. We validated detection of electrical activation and V m morphology against alternative nonoptical technologies. Nonantegrade slow waves and propagation direction differences between the anterior and posterior stomach were commonly present in our data. However, sham experiments suggest they were a feature of the animal preparation and not an artifact of optical mapping. In experiments to demonstrate the method's capabilities, we found that repolarization did not always follow at a fixed time behind activation "wavefronts," which could be a factor in dysrhythmia. Contraction strength and the latency between electrical activation and contraction differed between antegrade and nonantegrade propagation. In conclusion, optical electromechanical mapping, which simultaneously images electrical and mechanical activity, enables novel questions regarding normal and abnormal gastric physiology to be explored. NEW & NOTEWORTHY This article introduces a novel method for imaging gastric electrophysiology and mechanical function simultaneously in anesthetized, open-abdomen pigs. We demonstrate it by observing propagating slow-wave depolarization and repolarization along with the strength, spatial distribution, and direction of contractions. In addition, we observe that in this animal preparation, slow waves often do not propagate from the proximal to distal stomach and are frequently asymmetric between the anterior and posterior sides of the stomach.

Gut peristaltic movements transport ingested materials along the gut axis, which is critical for food digestion and nutrient absorption. While a large amount of studies have been devoted to analyzing the physiological functions of peristalsis in adults, little is known about how the peristaltic system is established during embryogenesis. In recent years, the chicken developing gut has emerged as an excellent model, in which specific sites along the gut axis can be genetically labeled enabling live imaging and optogenetic analyses. This review provides an overview of recent progress in optogenetic studies of gut peristalsis. Analyses with an improved channelrhodopsin-2 variant demonstrated that the peristalsis can artificially be generated in the developing gut. These studies unveiled novel functional coordination between different regions along the gut axis. In addition, imaging with GCaMP6s, a genetically encoded calcium indicator, enabled a fine mapping of developmental changes in the peristaltic patterns as Ca2+ signals. These advanced techniques will broaden our knowledge of how embryonic peristalsis is established at the cellular and molecular level, leading to the understanding of physiological and pathological processes in adult peristalsis., (© 2024 The Author(s). Published by Portland Press Limited on behalf of the Biochemical Society.)

Background: Functional lumen imaging probe (FLIP) panometry evaluates esophageal motility, including the contractile response to distension, that is, secondary peristalsis. Impaired/disordered contractile response (IDCR) is an abnormal, but nonspecific contractile response that can represent either hypomotility or spastic motor disorders on high-resolution manometry (HRM). We hypothesized that FLIP pressure could be incorporated to clarify IDCR and aimed to determine its utility in a cohort of symptomatic esophageal motility patients., Methods: 173 adult patients that had IDCR on FLIP panometry and HRM with a conclusive Chicago Classification v4.0 (CCv4.0) diagnosis were included and analyzed as development (n = 118) and validation (n = 55) cohorts. FLIP pressure values were assessed for prediction of either hypomotility or spasm, defined on HRM/CCv4.0., Key Results: HRM/CCv4.0 diagnoses were normal motility in 48 patients (28%), "hypomotility" (ineffective esophageal motility, absent contractility, or Type I or II achalasia) in 89 (51%), and "spasm" (Type III achalasia, distal esophageal spasm, or hypercontractile esophagus) in 36 (21%). The pressure at esophagogastric junction-distensibility index (DI) (60 mL) was lower in hypomotility (median [interquartile range] 34 [28-42] mmHg) than in spasm (49 [40-62] mmHg; p < 0.001) and had an area under the receiver operating characteristic curve of 0.80 (95% CI 0.73-0.88) for hypomotility and 0.76 (0.69-0.83) for spasm. For "spasm" on HRM, a threshold FLIP pressure of >35 mmHg provided 90% sensitivity (47% specificity) while >55 mmHg provided 93% specificity (40% sensitivity)., Conclusion & Inferences: Pressure on FLIP panometry can help clarify the significance of IDCR, with low-pressure IDCR associated with hypomotility and high-pressure IDCR suggestive of spastic motor disorders., (© 2024 The Authors. Neurogastroenterology & Motility published by John Wiley & Sons Ltd.)

In this paper, we introduce the numerical strategy for mixed uncertainty propagation based on probability and Dempster-Shafer theories, and apply it to the computational model of peristalsis in a heart-pumping system. Specifically, the stochastic uncertainty in the system is represented with random variables while epistemic uncertainty is represented using non-probabilistic uncertain variables with belief functions. The mixed uncertainty is propagated through the system, resulting in the uncertainty in the chosen quantities of interest (QoI, such as flow volume, cost of transport and work). With the introduced numerical method, the uncertainty in the statistics of QoIs will be represented using belief functions. With three representative probability distributions consistent with the belief structure, global sensitivity analysis has also been implemented to identify important uncertain factors and the results have been compared between different peristalsis models. To reduce the computational cost, physics constrained generalized polynomial chaos method is adopted to construct cheaper surrogates as approximations for the full simulation., (© 2024. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Introduction: Post-reflux swallow-induced peristaltic wave index (PSPWI) and mean nocturnal baseline impedance (MNBI) are novel parameters reflect esophageal clearance capacity and mucosal integrity. They hold potential in aiding the recognition of gastroesophageal reflux-induced chronic cough (GERC). Our study aims to investigate their diagnostic value in GERC., Methods: This study included patients suspected GERC. General information and relevant laboratory examinations were collected, and final diagnosis were determined following guidelines for chronic cough. The parameters of multichannel intraluminal impedance-pH monitoring (MII-pH) in patients were analyzed and compared to explore their diagnostic value in GERC., Results: A total of 186 patients were enrolled in this study. The diagnostic value of PSPWI for GERC was significant, with the area under the working curve (AUC) of 0.757 and a cutoff value of 39.4%, which was not statistically different from that of acid exposure time (AET) (p > 0.05). The combined diagnostic value of AET > 4.4% and PSPWI < 39.4% was superior to using AET > 4.4% alone (p < 0.05). Additionally, MNBI and distal MNBI also contributed to the diagnosis of GERC, with AUC values of 0.639 and 0.624, respectively. AET > 4.4% or PSPWI < 39.4% is associated with a 44% reduction in missed diagnoses of non-acid GERC compared to AET > 6.0% or symptom association probability (SAP) ≥ 95%, and may be more favorable for identifying GERC., Conclusion: The diagnostic value of PSPWI for GERC is comparable to that of AET. Combining PSPWI < 39.4% or AET > 4.4% can improve the diagnostic efficiency by reducing the risk of missed diagnoses in cases where non-acid reflux is predominant. Distal MNBI and MNBI can serve as secondary reference indices in the diagnosis of GERC., (© 2024. The Author(s).)

During pharyngeal phase of swallowing, circumferential tension of the cervical esophagus (CTE) increases caused by a biomechanical process of laryngeal elevation pulling the cervical esophagus orad. The esophagus contracts longitudinally during esophageal peristalsis, therefore, we hypothesized that CTE increases during esophageal peristalsis by a biomechanical process. We investigated this hypothesis using 28 decerebrate cats instrumented with electromyographic (EMG) electrodes on the pharynx and esophagus, and esophageal manometry. We recorded CTE, distal esophageal longitudinal tension (DET), and orad laryngeal tension (OLT) using strain gauges. Peristalsis was stimulated by injecting saline into esophagus or nasopharynx. We investigated the effects of transecting the pharyngo-esophageal nerve (PEN), hypoglossal nerve (HG), or administering (10 mg/kg iv) hexamethonium (HEX). We found that the durations of CTE and DET increased and OLT decreased simultaneously during the total extent of esophageal peristalsis. CTE duration was highly correlated with DET but not esophageal EMG or manometry. The peak magnitudes of the DET and CTE were highly correlated. After HEX administration, peristalsis in the distal esophagus did not occur, and the duration of the CTE response decreased. PEN transection blocked the occurrence of cricopharyngeal or cervical esophageal response during peristalsis but had no significant effect on the CTE response. HG transection had no significant effect on CTE. We conclude that there is a significant CTE increase, independent of laryngeal elevation or esophageal muscle contraction, which occurs during esophageal peristalsis. This response is a biomechanical process caused by esophageal shortening that occurs during esophageal longitudinal contraction of esophageal peristalsis. NEW & NOTEWORTHY Circumferential tension of cervical esophagus (CTE) increases during esophageal peristalsis. CTE response is correlated with distal longitudinal tension on cervical esophagus during esophageal peristalsis but not laryngeal elevation or esophageal muscle contraction. CTE response is not blocked by transection of motor innervation of laryngeal elevating muscles or proximal esophagus but is temporally reduced after hexamethonium administration. We conclude that the CTE response is a biomechanical effect caused by longitudinal esophageal contraction during esophageal peristalsis.

Menthol is thought to trigger gastroesophageal reflux disease (GERD) symptoms by influencing esophageal peristalsis and lower esophageal sphincter (LES) function. We evaluated the effect of esophageal menthol infusion on esophageal motility and the LES in healthy volunteers and in patients with GERD. High resolution manometry (HRM) catheter with attached thin tube for menthol infusion was placed transnasally. Protocol which included baseline recording, 16 water swallows (5 ml, 10 ml, and 15 ml) and the multiple rapid swallows was performed before and after esophageal infusion of menthol (3 mM, 20 min, 8 ml/min). We evaluated the effect of this infusion on the HRM parameters of esophageal peristalsis (distal contractile integral, distal latency, contractile front velocity) and the lower esophageal sphincter (LES) barrier function (integrated relaxation pressure and the inspiratory augmentation of the LES). Simultaneously we evaluated the quality and intensity of the symptoms during the menthol infusion. Esophageal infusion of menthol did not appreciably affect HRM measurements characterizing esophageal peristalsis and LES pressure in healthy subjects (N = 13) or GERD patients (N = 11). The magnitude of the distal contractile integral (5 ml) was changed neither in the healthy volunteers' group, (735 ± 127 vs. 814 ± 117 mmHg, p = 0.5), nor in the GERD patients (295 ± 78 vs. 338 ± 96 mmHg, p = 0.99). In healthy volunteers menthol did not change the inspiratory augmentation of the LES (8.67 ± 1.09 vs. 7.69 ± 0.96 mmHg, p = 0.15) and neither did for GERD patients (8.8 ± 1.18 vs. 8.22 ± 0.91 mmHg, p = 0.43). We observed no significant difference in any HRM parameter following menthol infusion, except for distal latency in 10 ml swallows. By contrast, menthol infusion induced significantly more intense discomfort in GERD patient than in healthy volunteers. Our results suggest no significant temporal effect of menthol on the esophageal motility or LES function, neither in healthy volunteers, nor in GERD. Arguably, other mechanisms are responsible for menthol-related heartburn., (© 2023. The Author(s).)

In the modern era, the utilization of electro-kinetic-driven microfluidic pumping procedures spans various biomedical and physiological domains. The present study introduces a mathematical framework for characterizing the hemodynamics of peristaltic blood flow within a porous tube infused with ZrO 2 nanoparticles. This model delves into the interactions between buoyancy, electro-osmotic forces, and aggregated nanoparticles to discern their influence on blood flow. We employ a third-grade fluid model to elucidate the rheological behavior of the pseudoplastic fluid which refers to its response to applied shear stress, specifically the relationship between shear rate and viscosity. The collective influence of accommodating heat convection, joule heating and aggregated nanoparticles contributes to the thermal behavior of fluids. The distribution of electric potential within the electric double layer (EDL) is predicted by solving the Poisson-Boltzmann equation. The rescaled equations are simplified using the lubrication and Debye-Hückel models as the underlying frameworks. The novel homotopy perturbation method is employed to obtain solutions for the finalized non-linear partial differential equation. Theoretical assessment of hemodynamic impacts involves plotting graphical configurations for various emerging parameters. As electro-osmotic parameter increase, the bloodstream encounters greater impedance, thereby enhancing the effectiveness of electro-osmotic assistance. Concurrently, elevated convective heat markedly reduces the rate of heat transfer, potentially resulting in a drop in blood temperature. It is important to note that maximum shear stress occurs when the artery is positioned horizontally, underscoring the significant impact of arterial alignment on wall shear stress. Skin friction intensifies with the increasing wall permeability as aggregated nanofluids pass through the arterial conduit. Therefore, aggregation of nanoparticles into the bloodstream yields a broader spectrum of distinctive physiological features. In summary, these findings enable more effective tool and device designs for addressing medication administration challenges and electro-therapies., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

In the past studies, the resistance of magnetically controlled capsules running through the small intestine has been modeled assuming that the small intestine was a circular tube with a constant diameter. Peristalsis is an important character of the human gastrointestinal system, and it would result in some changes in the diameter of the intestine, meaning that the existing resistance models would no longer be applicable. In this paper, based on the assumption that intestinal peristalsis is actually a sinusoidal wave, a resistance model of the capsule running in the peristaltic intestine is established, and then it is validated experimentally. The model provides a realistic foundation for the optimization and control of the magnetically controlled endoscopy., Competing Interests: Declaration of conflicting interestsThe author(s) declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.

Background: No studies have appeared in the literature evaluating the intraluminal volume of injected saline in the canine colon for performing leak tests in colotomy incisions., Aim: To determine the volume of the injected intraluminal saline necessary to achieve an intraluminal pressure of 17.3 cm H 2 O in 10 cm colonic segments containing a closed colotomy occluded with intestinal forceps or by digital pressure., Methods: Fresh colon was obtained from 8 canine cadavers and divided into 10 cm segments. A 3 cm antimesenteric colonic incision was performed at each intestinal segment which was closed using a 3-0 polydioxanone suture in a simple continuous pattern. Each colonic construct was occluded with Doyen intestinal forceps or by digital pressure and a leak test was performed by saline infusion. The saline volume needed to achieve a predetermined intraluminal pressure of 17.3 cm H 2 O, following occlusion was recorded., Results: The mean volume of injected saline with the Doyen intestinal forceps occlusion (20.4 ± 8.2 ml) was significantly larger than that of the digital occlusion technique (17.5 ± 6.8 ml) [ p = 0.021]., Conclusion: For 10 cm canine colonic constructs containing a closed colotomy, saline volumes of 20.4 ml with Doyen occlusion and 17.5 ml with digital occlusion can be utilized to achieve intraluminal pressures of 17.3 cm H 2 O., Competing Interests: The authors declare that there is no conflict of interest.

Background: The post-reflux swallow-induced peristaltic wave (PSPW) brings salivary bicarbonate to neutralize residual distal esophageal mucosal acidification., Aims: To determine if reduced saliva production and esophageal body hypomotility would compromise PSPW-induced pH recovery in the distal esophagus., Methods: In this multicenter retrospective cross-sectional study, patients with confirmed Sjogren's syndrome and scleroderma/mixed connective tissue disease (MCTD) who underwent high resolution manometry (HRM) and ambulatory pH-impedance monitoring off antisecretory therapy were retrospectively identified. Patients without these disorders undergoing HRM and pH-impedance monitoring for GERD symptoms were identified from the same time-period. Acid exposure time, numbers of reflux episodes and PSPW, pH recovery with PSPW, and HRM metrics were extracted. Univariate comparisons and multivariable analysis were performed to determine predictors of pH recovery with PSPW., Results: Among Sjogren's syndrome (n = 34), scleroderma/MCTD (n = 14), and comparison patients with reflux symptoms (n = 96), the scleroderma/MCTD group had significantly higher AET, higher prevalence of hypomotility, lower detected reflux episodes, and very low numbers of PSPW (p ≤ 0.004 compared to other groups). There was no difference in pH-impedance metrics between Sjogren's syndrome, and comparison patients (p ≥ 0.481). Proportions with complete pH recovery with PSPW was lower in Sjogren's patients compared to comparison reflux patients (p = 0.009), predominantly in subsets with hypomotility (p < 0.001). On multivariable analysis, diagnosis of Sjogren's syndrome, scleroderma/MCTD or neither (p = 0.014) and esophageal hypomotility (p = 0.024) independently predicted lack of complete pH recovery with PSPW, while higher total reflux episodes trended (p = 0.051)., Conclusions: Saliva production and motor function are both important in PSPW related pH recovery., (© 2024. The Author(s), under exclusive licence to Springer Science+Business Media, LLC, part of Springer Nature.)

This study aimed to investigate the relationship between endoscopic gastroesophageal valve grading and mean nocturnal baseline impedance (MNBI) and postreflux swallow-induced peristaltic wave index (PSPWI) in patients with gastroesophageal reflux disease (GERD). A total of 120 patients diagnosed with GERD disease were included in the study. According to the classification of endoscopic gastroesophageal valves, the patients were divided into 5 groups, group 1 as baseline group, and Group 2-4 as Hill grade I-IV. Basic information about the patients was collected, including age and gender. The mean nocturnal baseline impedance and creep wave index induced by swallowing after rumination were measured by high resolution creep measurement technique. Through statistical analysis, the relationship between valve classification and observation index was discussed. In terms of MNBI, impedance values gradually decreased with increasing valve classification. The average impedance of the Grade 1 group was 23.5 mm Hg/cm2, while the average impedance of the Grade 5 group was 15.2 mm Hg/cm2. This reduction showed a significant decreasing trend (P < .001). In addition, in terms of the peristaltic wave index caused by swallowing after regurgitation, the peristaltic wave index gradually increased with the increase of valve classification. The mean index in the Grade 1 group was 1.8 beats/min, while the mean index in the Grade 5 group was 3.6 beats/min. This increase showed a significant positive relationship (P < .001). Endoscopic gastroesophageal valve grading was significantly correlated with MNBI and PSPWI in patients with GERD. These observations can serve as useful tools for assessing the severity of GERD and monitoring disease progression., Competing Interests: The authors have no funding and conflicts of interest to disclose., (Copyright © 2024 the Author(s). Published by Wolters Kluwer Health, Inc.)

Introduction: The EndoFLIP (for its acronym in English: endoluminal functional luminal probe) is a system that measures in real time the compliance index of the gastroesophageal junction and secondary esophageal peristalsis, based on the principle of impedance planimetry. Although this technology is relatively new and its diagnostic usefulness is still being evaluated, its use in clinical practice is increasingly recognized, fundamentally in those patients where there is no conclusive manometric diagnosis of esophageal motor pathology, mainly esophagogastric junction outflow obstruction and achalasia., Objective: The aim of the present study is to describe the experience with EndoFLIP at the San Ignacio University Hospital in Bogotá, Colombia., Material and Methods: Descriptive observational case series study, which included patients over 18 years of age who had undergone EndoFLIP at the San Ignacio University Hospital from 2021 to 2022, either in-hospital or outpatient, with a clear indication of performance of the study, previously discussed in the multidisciplinary Gastroenterology Board., Results: A total of 27 patients with an average age of 55 years were included in the study, of which 20 were women (74%) and 7 men (26%). The most frequent indication of the study was an inconclusive diagnosis of outflow tract obstruction identified in high-resolution esophageal manometry according to Chicago 4.0 criteria (14 patients), followed by hypercontractile esophagus (4 patients) and ineffective esophageal motility (3 patients). When evaluating the contractile response, it was found that 9 patients with an inconclusive diagnosis of outflow tract obstruction had a normal response, 3 absent and one altered; and in the patients with an inconclusive diagnosis of achalasia, one of them had a borderline contractile response and two had no response. All patients with a previous diagnosis of absent contractility had an equally absent contractile response in EndoFLIP., Conclusion: Endoluminal functional luminal imaging is a technique that evaluates biomechanical properties such as distensibility, volume, pressure and even diameters of sphincter regions such as the gastroesophageal junction, pylorus and anus. Its usefulness has been highlighted for several indications, the most important being manometrically inconclusive diagnoses of esophageal motor disorders such as achalasia and outflow tract obstruction, pathologies that have a significant impact on the quality of life of patients and whose diagnosis is essential to be able to provide the best treatment option.

Purpose: The etiology of ureteral dilation in primary nonrefluxing, nonobstructing megaureters is still not well understood. Impaired ureteral peristalsis has been theorized as one of the contributing factors. However, ureteral peristalsis and its "normal" function is not well defined. In this study, using mathematical modeling techniques, we aim to better understand how ureteral peristalsis works. This is the first model to consider clinically observed, back-and-forth, cyclic wall longitudinal motion during peristalsis. We hypothesize that dysfunctional ureteral peristalsis, caused by insufficient peristaltic amplitudes (e.g., circular muscle dysfunction) and/or lack of ureteral wall longitudinal motion (e.g., longitudinal muscle dysfunction), promotes peristaltic reflux (i.e., retrograde flow of urine during an episode of peristalsis) and may result in urinary stasis, urine accumulation, and consequent dilation., Methods: Based on lubrication theory in fluid mechanics, we developed a two-dimensional (planar) model of ureteral peristalsis. In doing so, we treated ureteral peristalsis as an infinite train of sinusoidal waves. We then analyzed antegrade and retrograde flows in the ureter under different bladder-kidney differential pressure and peristalsis conditions., Results: There is a minimum peristaltic amplitude required to prevent peristaltic reflux. Ureteral wall longitudinal motion decreases this minimum required amplitude, increasing the nonrefluxing range of peristaltic amplitudes. As an example, for a normal bladder-kidney differential pressure of 5 cmH 2 O, ureteral wall longitudinal motion increases nonrefluxing range of peristaltic amplitude by 65%. Additionally, ureteral wall longitudinal motion decreases refluxing volumetric flow rates. For a similar normal bladder pressure example of 5 cmH 2 O, refluxing volumetric flow rate decreases by a factor of 18. Finally, elevated bladder pressure, not only increases the required peristaltic amplitude for reflux prevention but it increases maximum refluxing volumetric flow rates. For the case without wall longitudinal motion, as bladder-kidney differential pressure increases from 5 to 40 cmH 2 O, minimum required peristaltic amplitude to prevent reflux increases by 40% while the maximum refluxing volumetric flow rate increases by approximately 100%., Conclusion: The results presented in this study show how abnormal ureteral peristalsis, caused by the absence of wall longitudinal motion and/or lack of sufficient peristaltic amplitudes, facilitates peristaltic reflux and retrograde flow. We theorize that this retrograde flow can lead to urinary stasis and urine accumulation in the ureters, resulting in ureteral dilation seen on imaging studies and elevated infection risk. Our results also show how chronically elevated bladder pressures are more susceptible to such refluxing conditions that could lead to ureteral dilation., (© 2023 The Authors. Neurourology and Urodynamics published by Wiley Periodicals LLC.)

Assessing gastrointestinal motility lacks simultaneous evaluation of intraluminal pressure (ILP), circular muscle (CM) and longitudinal muscle (LM) contraction, and lumen emptying. In this study, a sophisticated machine was developed that synchronized real-time recordings to quantify the intricate interplay between CM and LM contractions, and their timings for volume changes using high-resolution cameras with machine learning capability, the ILP using pressure transducers and droplet discharge (DD) using droplet counters. Results revealed four distinct phases, B Phase , N Phase , D Phase , and A Phase , distinguished by pressure wave amplitudes. Fluid filling impacted LM strength and contraction frequency initially, followed by CM contraction affecting ILP, volume, and the extent of anterograde, retrograde, and segmental contractions during these phases that result in short or long duration DD. This comprehensive analysis sheds light on peristalsis mechanisms, understand their sequence and how one parameter influenced the other, offering insights for managing peristalsis by regulating smooth muscle contractions., (© 2023. This is a U.S. Government work and not under copyright protection in the US; foreign copyright protection may apply.)

In isolated segments of the rat proximal colon, the dopamine reuptake inhibitor GBR 12909 (GBR) causes a dilatation, while the D 1 -like receptor antagonist SCH 23390 (SCH) induces a tonic constriction, suggesting that neurally released dopamine tonically stimulates enteric inhibitory efferent neurons. Here, the targets of the enteric dopaminergic neurons were investigated. Cannulated segments of rat proximal colon were bathed in physiological salt solution and luminally perfused with 0.9% saline, while all drugs were applied to the bath. Spatio-temporal maps of colonic motility were constructed from video recordings of peristaltic contractions, and the maximum diameter was measured as an index of colonic contractility. GBR (1 μM)-induced dilatations of colonic segments were prevented by SCH (5 μM), L-nitro arginine (L-NA; 100 μM), a nitric oxide synthase inhibitor, or tetrodotoxin (0.6 μM). In contrast, constrictions induced by a higher concentration of SCH (20 μM) were unaffected by either L-NA or tetrodotoxin. The vasoactive intestinal peptide (VIP) receptor antagonist VIP 10-28 (3 μM) or P2Y 1 receptor antagonist MRS 2500 (1 μM) had no effect on either the GBR-induced dilatation or the SCH-induced constriction. In colonic segments that had been pretreated with 6-hydroxydopamine (100 μM, 3 h) to deplete enteric dopamine, GBR failed to increase the colonic diameter, while SCH was still capable of constricting colonic segments. Enteric dopaminergic neurons appear to project to nitrergic neurons to dilate the proximal colon by activating neuronal D 1 -like receptors. In addition, constitutively activated D 1 -like receptors expressed in cells yet to be determined may provide a tonic inhibition on colonic constrictions., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Background: Lung transplantation (LTx) remains controversial in patients with absent peristalsis (AP) given the increased risk for gastroesophageal reflux (GER), and chronic lung allograft dysfunction. Furthermore, specific treatments to facilitate LTx in those with AP have not been widely described. Transcutaneous Electrical Stimulation (TES) has been reported to improve foregut contractility in LTx patients and therefore we hypothesize that TES may augment the esophageal motility of patients with ineffective esophageal motility (IEM)., Methods: We included 49 patients, 14 with IEM, 5 with AP, and 30 with normal motility. All subjects underwent standard high-resolution manometry and intraluminal impedance (HRIM) with additional swallows as TES was delivered., Results: TES induced a universal impedance change observable in real-time by a characteristic spike activity. TES significantly augmented the contractile vigor of the esophagus measured by the distal contractile integral (DCI) in patients with IEM [median DCI (IQR) 0 (238) mmHg-cm-s off TES vs. 333 (858) mmHg-cm-s on TES; p = .01] and normal peristalsis [median DCI (IQR) 1545 (1840) mmHg-cm-s off TES vs. 2109 (2082) mmHg-cm-s on TES; p = .01]. Interestingly, TES induced measurable contractile activity (DCI > 100 mmHg-cm-s) in three out of five patients with AP [median DCI (IQR) 0 (0) mmHg-cm-s off TES vs. 0 (182) mmHg-cm-s on TES; p < .001]., Conclusion: TES acutely augmented contractile vigor in patients with normal and weak/ AP. The use of TES may positively impact LTx candidacy, and outcomes for patients with IEM/AP. Nevertheless, further studies are needed to determine the long-term effects of TES in this patient population., (© 2023 The Authors. Clinical Transplantation published by John Wiley & Sons Ltd.)

Background: Effect of inter-swallow interval on the contractility of smooth muscle esophagus is well-documented. However, the effects on peristalsis of the striated esophagus have not been systematically studied. A better understanding of striated esophagus motor function in health and disease may enhance the interpretation of manometric studies and inform clinical care. The aim of this study was to assess the effect of inter-swallow interval on striated esophagus compared to findings with that of the smooth muscle esophagus., Methods: We performed two sets of studies to (1) determine the effect of various inter-swallow interval in 20 healthy volunteers and (2) assess the effect of ultra-short swallow intervals facilitated by straw drinking in 28 volunteers. We analyzed variables using ANOVA with Tukey's pairwise comparison and paired t-test., Key Results: Unlike smooth muscle esophagus, the striated esophagus contractile integral did not change significantly for swallow intervals ranging from 30 to 5 s. On the contrary, striated esophagus demonstrated absent or reduced peristalsis in response to ultra-short (<2 s) intervals during straw-facilitated multiple rapid swallows., Conclusions and Inferences: Striated esophagus peristalsis is subject to manometrically observed inhibition during swallows with ultra-short intervals. Inter-swallow intervals as short as 5 s that inhibit smooth muscle esophagus peristalsis do not inhibit striated muscle peristalsis. The mechanisms of these observations are unknown but may relate to central or myenteric nervous system influences or the effects of pharyngeal biomechanics., (© 2023 John Wiley & Sons Ltd.)

In this work, simulations of intestinal peristalsis are performed to investigate the intraluminal transport of macromolecules (MMs) and permeation enhancers (PEs). Properties of insulin and sodium caprate (C 10 ) are used to represent the general class of MM and PE molecules. Nuclear magnetic resonance spectroscopy was used to obtain the diffusivity of C 10 , and coarse-grain molecular dynamics simulations were carried out to estimate the concentration-dependent diffusivity of C 10 . A segment of the small intestine with the length of 29.75 cm was modeled. Peristaltic speed, pocket size, release location, and occlusion ratio of the peristaltic wave were varied to study the effect on drug transport. It was observed that the maximum concentration at the epithelial surface for the PE and the MM increased by 397 % and 380 %, respectively, when the peristaltic wave speed was decreased from 1.5 to 0.5 cm s -1 . At this wave speed, physiologically relevant concentrations of PE were found at the epithelial surface. However, when the occlusion ratio is increased from 0.3 to 0.7, the concentration approaches zero. These results suggest that a slower-moving and more contracted peristaltic wave leads to higher efficiency in transporting mass to the epithelial wall during the peristalsis phases of the migrating motor complex., Competing Interests: Declaration of competing interest The authors declare that there are no conflicts of interest., (Copyright © 2023 The Authors. Published by Elsevier B.V. All rights reserved.)

In this paper, the tools of dynamical systems theory are applied to examine the streamline patterns and their local and global bifurcations for ciliary-induced peristalsis of non-Newtonian fluid (blood) with the suspension of hybrid nanoparticles (Cu-Ag/Phan-Thien-Tanner based fluid) in a tube with heat source effect. The thermodynamics of this model are recently described by Ali et al. (Biomech Model Mechanobiol 20:2393-2412, 2021), where the fluid flows through a tube whose inner walls are considered to be ciliated with small hair-like structures. However, our novel approach allows us to create a complete picture of the model's overall dynamic behavior in terms of bifurcation point analysis exhibiting qualitatively different flow modes. Special attention is paid to the computing, analysis and simulation of equilibrium points in terms of capturing the global dynamics, such as evaluating the heteroclinic bifurcation, which is used to identify trapping phenomena in response to biological characteristics such as wave amplitude, Weissenberg and wave numbers. The main novelty here is the ability to control the position of the equilibrium points in the domain of interest, allowing one to identify global bifurcations that reflect key dynamic properties of the model. Based on the advantages of this technique, the maximum trapping volume and symmetric trapping zones adjacent to the walls are determined as a novel result. We also show that as the solid volume fraction of copper and the Brinkman number increases, the isotherm patterns become more distorted. Our findings highlight a novel class of complex behavior that governs transitions between qualitatively different modes and trapping phenomena., (© 2023. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

In situated theoretical article, a study of peristaltic transition of Jeffery nanofluid comprising motile gyrotactic microorganisms is exposed. The movement floods due to anisotropically stenosed endoscope influenced by Hall current, Joule heating during Darcy-Forchheimer feature. Influences of nonlinear thermic radiation, chemical interactions as well as Soret and Dufour scheme are exhibited. To ameliorate the competence of this article, activation energy has been appended to concentration of nano-particles due to the amended Arrhenius scheme and Buongiorno type. The slip stipulation is deemed relative to the speed scheme. Meanwhile, convective stipulation is reckoned for temperature. The proposition of protracted wavelength besides subdued Reynolds numeral is regulated to transit the manner of partial differential formulations that judges the fluid movement to ordinary one. Homotopy perturbation manner is tackled to manage the traditional solutions of generated neutralizations. Influences of assorted factors of the issue are debated and schematically showed with a class of charts. The situated study grants a medication for the malign cells and clogged arteries of the heart by manner of penetrating a slender tube (catheter). Also, this study may represent the depiction of the gastric juice movement in small intestine when an endoscope is permeating across it., (© 2023. The Author(s).)

A FLIP device gives cross-sectional area along the length of the esophagus and one pressure measurement, both as a function of time. Deducing mechanical properties of the esophagus including wall material properties, contraction strength, and wall relaxation from these data are a challenging inverse problem. Knowing mechanical properties can change how clinical decisions are made because of its potential for in-vivo mechanistic insights. To obtain such information, we conducted a parametric study to identify peristaltic regimes by using a 1D model of peristaltic flow through an elastic tube closed on both ends and also applied it to interpret clinical data. The results gave insightful information about the effect of tube stiffness, fluid/bolus density and contraction strength on the resulting esophagus shape through quantitive representations of the peristaltic regimes. Our analysis also revealed the mechanics of the opening of the contraction area as a function of bolus flow resistance. Lastly, we concluded that peristaltic driven flow displays three modes of peristaltic geometries, but all physiologically relevant flows fall into two peristaltic regimes characterized by a tight contraction., (© 2022. The Author(s), under exclusive licence to Springer-Verlag GmbH Germany, part of Springer Nature.)

Robotic locomotion in subterranean environments is still unsolved, and it requires innovative designs and strategies to overcome the challenges of burrowing and moving in unstructured conditions with high pressure and friction at depths of a few centimeters. Inspired by antagonistic muscle contractions and constant volume coelomic chambers observed in earthworms, we designed and developed a modular soft robot based on a peristaltic soft actuator (PSA). The PSA demonstrates two active configurations from a neutral state by switching the input source between positive and negative pressure. PSA generates a longitudinal force for axial penetration and a radial force for anchorage, through bidirectional deformation of the central bellows-like structure, which demonstrates its versatility and ease of control. The performance of PSA depends on the amount and type of fluid confined in an elastomer chamber, generating different forces and displacements. The assembled robot with five PSA modules enabled to perform peristaltic locomotion in different media. The role of friction was also investigated during experimental locomotion tests by attaching passive scales like earthworm setae to the ventral side of the robot. This study proposes a new method for developing a peristaltic earthworm-like soft robot and provides a better understanding of locomotion in different environments., (© 2023. The Author(s).)

Peristalsis is a nuanced mechanical stimulus comprised of multi-axial strain (radial and axial strain) and shear stress. Forces associated with peristalsis regulate diverse biological functions including digestion, reproductive function, and urine dynamics. Given the central role peristalsis plays in physiology and pathophysiology, we were motivated to design a bioreactor capable of holistically mimicking peristalsis. We engineered a novel rotating screw-drive based design combined with a peristaltic pump, in order to deliver multi-axial strain and concurrent shear stress to a biocompatible polydimethylsiloxane (PDMS) membrane "wall." Radial indentation and rotation of the screw drive against the wall demonstrated multi-axial strain evaluated via finite element modeling. Experimental measurements of strain using piezoelectric strain resistors were in close alignment with model-predicted values (15.9 ± 4.2% vs. 15.2% predicted). Modeling of shear stress on the "wall" indicated a uniform velocity profile and a moderate shear stress of 0.4 Pa. Human mesenchymal stem cells (hMSCs) seeded on the PDMS "wall" and stimulated with peristalsis demonstrated dramatic changes in actin filament alignment, proliferation, and nuclear morphology compared to static controls, perfusion, or strain, indicating that hMSCs sensed and responded to peristalsis uniquely. Lastly, significant differences were observed in gene expression patterns of calponin, caldesmon, smooth muscle actin, and transgelin, corroborating the propensity of hMSCs toward myogenic differentiation in response to peristalsis. Collectively, our data suggest that the peristalsis bioreactor is capable of generating concurrent multi-axial strain and shear stress on a "wall." hMSCs experience peristalsis differently than perfusion or strain, resulting in changes in proliferation, actin fiber organization, smooth muscle actin expression, and genetic markers of differentiation. The peristalsis bioreactor device has broad utility in the study of development and disease in several organ systems., (© 2022 S. Karger AG, Basel.)

In the present investigation, the effect of multi-slip condition on peristaltic flow through asymmetric channel with Joule heating effect is considered. We also considered the incompressible non-Newtonian Casson nanofluid model for blood, which is electrically conducting. Second law of thermodynamics is used to examine the entropy generation. Multi-slip condition is used at the boundary of the wall and the analysis is also restricted under the low Reynolds number and long wavelength assumption. The governing equations were transformed into a non-dimensional form by using suitable terms. The reduced non-dimensional highly nonlinear partial differential equations are solved by using the Homotopy Perturbation Sumudu transformation method (HPSTM). The influence of different physical parameters on dimensionless velocity, pressure gradient, temperature, concentration and nanoparticle is graphically presented. From the results, one can understand that the Joule heating effect controls the heat transfer in the system and as the magnetic parameter is increased, there will be decay in the velocity of fluid. The outcomes of the present investigation can be applicable in examining the chyme motion in the gastrointestinal tract and controlling the blood flow during surgery. Present study shows an excellent agreement with the previously available studies in the limiting case., (© 2022. The Author(s), under exclusive licence to Springer Nature B.V.)

Esophageal peristalsis consists of initial inhibition (relaxation) followed by excitation (contraction), both of which move sequentially in the aboral direction. Initial inhibition results in receptive relaxation and bolus-induced luminal distension, which allows propulsion by the contraction with minimal resistance to flow. Similar to the contraction wave, luminal distension has unique waveform characteristics in normal subjects; both are modulated by bolus volume, bolus viscosity, and posture, suggesting a possible cause-and-effect relationship between the two. Distension contraction plots in patients with dysphagia with normal bolus clearance [high-amplitude esophageal contractions (HAECs), esophagogastric junction outflow obstruction (EGJOO), and functional dysphagia (FD)] reveal two major findings: 1 ) unlike normal subjects, there is luminal occlusion distal to bolus during peristalsis in certain patients, i.e., with type 3 achalasia and nonobstructive dysphagia; and 2 ) bolus travels through a narrow lumen esophagus during peristalsis in patients with HAECs, EGJOO, and FD. Aforementioned findings indicate a relative dynamic obstruction to the bolus flow during peristalsis and reduced distensibility of esophageal wall in the bolus segment of the esophagus. We speculate that a normal or supernormal contraction wave pushing bolus against resistance is the mechanism of dysphagia sensation in significant number of patients. Representations of distension and contraction, combined with objective measures of flow timing and distensibility are complementary to the current scheme of classifying esophageal motility disorders based solely on the characteristics of contraction phase of peristalsis. Better understanding of the distensibility of the bolus-containing segment of the esophagus during peristalsis will lead to the development of novel medical and surgical therapies in the treatment of dysphagia in significant number of patients.

The process of urine removal from the kidney occurs via the renal pelvis (RP). The RP demarcates the beginning of the upper urinary tract and is endowed with smooth muscle cells. Along the RP, organized contraction of smooth muscle cells generates the force required to move urine boluses toward the ureters and bladder. This process is mediated by specialized pacemaker cells that are highly expressed in the proximal RP that generate spontaneous rhythmic electrical activity to drive smooth muscle depolarization. The mechanisms by which peristaltic contractions propagate from the proximal to distal RP are not fully understood. In this study, we utilized a transgenic mouse that expresses the genetically encoded Ca 2+ indicator, GCaMP3, under a myosin heavy chain promotor to visualize spreading peristaltic contractions in high spatial detail. Using this approach, we discovered variable effects of L-type Ca 2+ channel antagonists on contraction parameters. Inhibition of T-type Ca 2+ channels reduced the frequency and propagation distance of contractions. Similarly, antagonizing Ca 2+ -activated Cl - channels or altering the transmembrane Cl - gradient decreased contractile frequency and significantly inhibited peristaltic propagation. These data suggest that voltage-gated Ca 2+ channels are important determinants of contraction initiation and maintain the fidelity of peristalsis as the spreading contraction moves further toward the ureter. Recruitment of Ca 2+ -activated Cl - channels, likely Anoctamin-1, and T-type Ca 2+ channels are required for efficiently conducting the depolarizing current throughout the length of the RP. These mechanisms are necessary for the efficient removal of urine from the kidney., (© The Author(s) 2022. Published by Oxford University Press on behalf of American Physiological Society.)

Background/aim: The cold receptor, transient receptor potential melastatin 8 (TRPM8), has been reported to be expressed in esophageal vagal afferents. Esophageal infusion of menthol modulates esophageal perception in reflux patients via TRPM8, but the effects of menthol on esophageal motility are not well investigated. This study aimed to test the hypothesis whether the infusion of menthol into the esophagus could affect esophageal peristaltic characteristics., Methods: Eighteen healthy adults (men 13, mean age 27) underwent high-resolution manometry (HRM) using a catheter with the injection port located in mid-esophagus. Primary peristalsis was performed with ten wet swallows, while secondary peristalsis was generated by 10 rapid air injections. Two different sessions were randomly performed including acute administration of menthol (3 mM) and the placebo., Results: Menthol significantly decreased upper esophageal (UES) pressure of primary peristalsis than the placebo (p = 0.019). There was no difference in distal contractile integral (p = 0.33), distal latency (p = 0.86), basal lower esophageal sphincter pressure (p = 0.19), or 4-second integrated relaxation pressure (p = 0.75) between menthol and placebo. Menthol significantly decreased the frequency of secondary peristalsis subsequent to the administration of menthol during rapid injections with 20 mL air (p = 0.04)., Conclusions: Intraluminal infusion of menthol reduces UES basal pressure and inhibits peristaltic frequency of secondary peristalsis. The data suggest that the triggering of secondary peristalsis is probably modulated by TRPM8-sensitive mechanoreceptors; however, the activation of TRPM8 from menthol does not alter esophageal motility following deglutition or distension-induced secondary peristalsis., (© 2021 John Wiley & Sons Ltd.)

Regular intestinal motility is essential to guarantee complete digestive function. The coordinative action and integrity of the smooth muscle layers in the small intestine's wall are critical for mixing and propelling the luminal content. However, some patients present gastrointestinal limitations which may negatively impact the normal motility of the intestine. These patients have altered mechanical and muscle properties that likely impact chyme propulsion and may pose a daily scenario for long-term complications. To better understand how mechanics affect chyme propulsion, the propulsive capability of the small intestine was examined during a peristaltic wave along the distal direction of the tract. It was assumed that such a wave works as an activation signal, inducing peristaltic contractions in a transversely isotropic hyperelastic model. In this work, the effect on the propulsion mechanics, from an impairment on the muscle contractile ability, typical from patients with systemic sclerosis, and the presence of sores resultant from ulcers was evaluated. The passive properties of the constitutive model were obtained from uniaxial tensile tests from a porcine small intestine, along with both longitudinal and circumferential directions. Our experiments show decreased stiffness in the circumferential direction. Our simulations show decreased propulsion forces in patients in systemic sclerosis and ulcer patients. As these patients may likely need medical intervention, establishing action concerning the impaired propulsion can help to ease the evaluation and treatment of future complications., (© 2022 John Wiley & Sons Ltd.)

Background: Nasogastric (NG) intubation for esophageal manometry can be traumatic and may be associated with a temporary reduction/absence in esophageal peristalsis. This study explored the prevalence and effect on esophageal motor function. We also hypothesized that baseline anxiety as well as markers of autonomic nerve function were correlated to attenuated esophageal peristalsis., Methods: Twenty-seven patients with esophageal symptoms referred for esophageal manometry investigation (mean age 56.8 ± 16.7 years, range 23-85 years) reported baseline anxiety score (Likert scale) preintubation. Patients had continuous heart rate and blood pressure measured prior to intubation and until 10 min after catheter withdrawal. Quality of motility was assessed for each 5 ml water swallow using standard Chicago Classification metrics., Key Results: Nasogastric-intubation elicited a significant increase in heart rate (p < 0.001), systolic (p < 0.001) and diastolic (p < 0.001) blood pressure, which was in part anticipatory. The median time taken for patients' first hypotensive peristalsis (Distal Contractile Integral; DCI ≥100 mmHg s cm) was 130 s (Interquartile range; 47-242 s) and for their first normal peristalsis (DCI ≥450 mm Hg s cm) was 150 s (IQR 61-320 s), with improvement and consistent stabilization in DCI there onward. This corresponded closely to the time for initial recovery of heart rate and systolic and diastolic blood pressure postintubation., Conclusions and Inferences: Nasogastric intubation resulted in heightened sympathetic responses and/or dampened parasympathetic responses, and an associated temporary reduction or absence in esophageal peristalsis., (© 2021 John Wiley & Sons Ltd.)

Zebrafish larval gut could be considered as an excellent model to study functions of vertebrate digestive organs, by virtue of its simplicity and transparency as well as the availability of mutants. However, there has been scant investigation of the detailed behavior of muscular and enteric nervous systems to convey bolus, an aggregate of digested food. Here we visualized peristalsis using transgenic lines expressing a genetically encoded Ca 2+ sensor in the circular smooth muscles. An intermittent Ca 2+ signal cycle was observed at the oral side of the bolus, with Ca 2+ waves descending and ascending from there. We also identified a regular cycle of weaker movement that occurs regardless of the presence or absence of bolus, corresponding likely to slow waves. Direct photo-stimulation of circular smooth muscles expressing ChR2 could cause local constriction of the gut, while the stimulation of a single or a few neurons could cause the local induction or arrest of gut movements. These results indicate that the larval gut of zebrafish has basic features found in adult mammals despite the small number of enteric neurons, providing a foundation for the study, at the single-cell level in vivo, in controlling the gut behaviors in vertebrates., (© 2022. The Author(s).)

Background: Ineffective esophageal motility (IEM) is the most common motility disorder. However, little is known about its pathophysiology. Vagal afferent nerves convey esophageal intraluminal bolus information to solitary nucleus, which is likely to be involved with esophageal primary and secondary peristalsis (SP). We hypothesized that altered mucosal sensory afferents underlie the pathogenesis of IEM., Methods: We prospectively collected esophageal biopsies from 38 patients with proton pump inhibitor-refractory reflux symptoms from January to December 2019. All patients underwent high-resolution manometry for the evaluation of primary and secondary peristalsis, and off-PPI 24-h impedance-pH studies. Biopsies were analyzed using immunohistochemistry for identification of calcitonin gene-related peptide-immunoreactive (CGRP-IR) nerves and qPCR for mRNA expression of potential mechanoreceptors., Key Results: Overall 32 patients were finally analyzed which consisted of 11 patients with normal motility and 21 patients with IEM. The position of mucosal CGRP-IR nerves from the esophageal lumen did not differ between the two groups (the proximal esophagus (p = 0.52), the mid-esophagus (p = 0.92), the distal esophagus (p = 0.29)) with the similar reflux profile. No difference was seen in the position of CGRP-IR nerves between patients with successful triggering of SP and those unable to trigger SP. There was also no difference in mRNA expression of each potential mechanoreceptors (TRPA1, TRPV1, TRPV4, ASIC1, ASIC3) between the two groups., Conclusions and Inferences: Our study showed that mucosal sensory afferents nerve position and mRNA expression of potential mechanoreceptors did not correlate to weak esophageal contraction., (© 2021 John Wiley & Sons Ltd.)