Mean nocturnal baseline impedance in gastro-esophageal reflux disease diagnosis: Should we strictly follow the Lyon 2 Consensus?

Clinical practice guidelines drive clinical practice and clinicians rely to them when trying to answer their most common questions. One of the most important position papers in the field of gastro-esophageal reflux disease (GERD) is the one produced by the Lyon Consensus. Recently an updated second version has been released. Mean nocturnal baseline impedance (MNBI) was proposed by the first Consensus to act as supportive evidence for GERD diagnosis. Originally a cut-off of 2292 Ohms was proposed, a value revised in the second edition. The updated Consensus recommended that an MNBI < 1500 Ohms strongly suggests GERD while a value > 2500 Ohms can be used to refute GERD. The proposed cut-offs move in the correct direction by diminishing the original cut-off, nevertheless they arise from a study of normal subjects where cut-offs were provided by measuring the mean value ± 2SD and not in symptomatic patients. However, data exist that even symptomatic patients with inconclusive disease or reflux hypersensitivity (RH) show lower MNBI values in comparison to normal subjects or patients with functional heartburn (FH). Moreover, according to the data, MNBI, even among symptomatic patients, is affected by age and body mass index. Also, various studies have proposed different cut-offs by using receiver operating characteristic curve analysis even lower than the one proposed. Finally, no information is given for patients submitted to on-proton pump inhibitors pH-impedance studies even if new and extremely important data now exist. Therefore, even if MNBI is an extremely important tool when trying to approach patients with reflux symptoms and could distinguish conclusive GERD from RH or FH, its values should be interpreted with caution.

Value of pH Impedance Monitoring While on Twice-Daily Proton Pump Inhibitor Therapy to Identify Need for Escalation of Reflux Management.

BACKGROUND AND AIMS: Acid exposure time (AET) and reflux episode thresholds from the Lyon Consensus may not apply for pH impedance studies performed while on proton pump inhibitor (PPI) therapy. We aimed to determine metrics from "on PPI" pH impedance studies predicting need for escalation of therapy. METHODS: De-identified pH impedance studies performed while on twice-daily PPI (Diversatek, Boulder, CO) in healthy volunteers (n = 66, median age 37.5 years, 43.9% female), and patients with proven gastroesophageal reflux disease (GERD) (European heartburn-predominant cohort: n = 43, median age 57.0 years, 55.8% female; North American regurgitation-predominant cohort: n = 42, median age 41.6 years, 42.9% female) were analyzed. Median values and interquartile ranges for pH impedance metrics in healthy volunteers were compared with proven GERD patients with and without 50% symptom improvement on validated measures. Receiver operating characteristic (ROC) analyses identified optimal thresholds predicting symptom response. RESULTS: Both conventional and novel reflux metrics were similar between PPI responders and nonresponders (P ≥ .1 for each) despite differences from healthy volunteers. Combinations of metrics associated with conclusively abnormal reflux burden (AET >4%, >80 reflux episodes) were seen in 32.6% and 40.5% of heartburn and regurgitation-predominant patients, respectively, 57.1% and 82.4% of whom reported nonresponse; and 85% with these metrics improved with invasive GERD management. On ROC analysis, AET threshold of 0.5% modestly predicted nonresponse (sensitivity, 0.62; specificity, 0.51; P = .22), and 40 reflux episodes had better performance characteristics (sensitivity, 0.80; specificity, 0.51; P = .002); 79% with these metrics improved with invasive GERD management. CONCLUSION: Combinations of abnormal "on PPI" pH impedance metrics are associated with PPI nonresponse in proven GERD patients, and can be targeted for treatment escalation, including surgery, particularly in regurgitation-predominant GERD.

Heartburn sensation in nonerosive reflux disease: pattern of superficial sensory nerves expressing TRPV1 and epithelial cells expressing ASIC3 receptors.

The underlying causes of heartburn, characteristic symptom of gastroesophageal reflux disease (GERD), remain incompletely understood. Superficial afferent innervation of the esophageal mucosa in nonerosive reflux disease (NERD) may drive nociceptive reflux perception, but its acid-sensing role has not yet been established. Transient receptor potential vanilloid subfamily member-1 (TRPV1), transient receptor potential melastatin 8 (TRPM8), and acid-sensing ion channel 3 (ASIC3) are regulators of sensory nerve activity and could be important reflux-sensing receptors within the esophageal mucosa. We characterized TRPV1, TRPM8, and ASIC3 expression in esophageal mucosa of patients with GERD. We studied 10 patients with NERD, 10 with erosive reflux disease (ERD), 7 with functional heartburn (FH), and 8 with Barrett's esophagus (BE). Biopsies obtained from the distal esophageal mucosa were costained with TRPV1, TRPM8, or ASIC3, and CGRP, CD45, or E-cadherin. RNA expression of TRPV1, TRPM8, and ASIC3 was assessed using qPCR. Patients with NERD had significantly increased expression of TRPV1 on superficial sensory nerves compared with ERD (P = 0.028) or BE (P = 0.017). Deep intrapapillary nerve endings did not express TRPV1 in all phenotypes studied. ASIC3 was exclusively expressed on epithelial cells most significantly in patients with NERD and ERD (P ≤0.0001). TRPM8 was expressed on submucosal CD45+ leukocytes. Superficial localization of TRPV1-immunoreactive nerves in NERD, and increased ASIC3 coexpression on epithelial cells in NERD and ERD, suggests a mechanism for heartburn sensation. Esophageal epithelial cells may play a sensory role in acid reflux perception and act interdependently with TRPV1-expressing mucosal nerves to augment hypersensitivity in patients with NERD, raising the enticing possibility of topical antagonists for these ion channels as a therapeutic option.NEW & NOTEWORTHY We demonstrate for the first time that increased pain perception in patients with nonerosive reflux disease likely results from expression of acid-sensitive channels on superficial mucosal afferents and esophageal epithelial cells, raising the potential for topical therapy.

Detection and characteristics of rumination syndrome in patients presenting for gastric symptom evaluation.

BACKGROUND: Rumination syndrome involves effortless, repeated regurgitation, and can overlap with other upper gastrointestinal disorders, including gastroparesis. To inform better diagnostic detection of rumination, we aimed to (1) identify frequency and characteristics of rumination in patients presenting for gastric symptom evaluation; and (2) assess demographic and clinical characteristics that could differentiate those with versus those without rumination. METHODS: Consecutively referred patients to two tertiary academic centers for gastric symptom specialty evaluation were included (N = 242). We obtained demographic information, gastric emptying scintigraphy, upper gastrointestinal symptoms using the Patient Assessment of Upper Gastrointestinal Symptoms (PAGI-SYM), and Rome IV-based rumination questionnaire. KEY RESULTS: Thirty-one of the 242 (12.8%) patients met criteria for rumination syndrome, of which 48% reported associated psychosocial impairment. Comparing those with rumination and those without, there were no differences in race, gender, frequency of diabetes, or frequency of gastroparesis. The median PAGI-SYM score for rumination patients was higher than for those without (3.03 vs. 2.55; unadjusted p = 0.043, adjusted p = 0.30). This was largely driven by increased heartburn/regurgitation subscale scores (2.71 vs. 1.57, unadjusted p = 0.0067, adjusted p = 0.046), itself influenced by elevated daytime regurgitation/reflux (3.0 vs. 2.0; unadjusted p = 0.007, adjusted p = 0.048). There were no significant differences on the remaining PAGI-SYM subscales. CONCLUSIONS AND INFERENCES: Rumination syndrome determined by Rome IV criteria was present in 12.8% of patients presenting for gastric symptom evaluation. Higher self-report PAGI-SYM heartburn/regurgitation subscale scores, particularly daytime regurgitation/reflux symptoms, were the only parameters that distinguished rumination. The PAGI-SYM heartburn/regurgitation subscale could be used to screen for rumination, in addition to GERDAQ6.

Impact of COVID-19 lockdown on symptoms in patients with functional gastrointestinal disorders: Relationship with anxiety and perceived stress.

BACKGROUND: Psychological stress and anxiety, such those generated by forced quarantine, affect gastrointestinal symptoms course in patients with functional gastrointestinal disorders. Thus, our aim was to assess, in a cohort of patients regularly followed up in a devoted outpatient clinic of Southern Italy, the association between their gastrointestinal symptoms changes, stress, and anxiety reported during the Italian lockdown. METHODS: We recruited patients from the outpatient clinic of the University of Salerno, devoted to functional gastrointestinal disorders, selecting only patients for whom an evaluation was available in the last 6 months before the lockdown. Gastrointestinal symptoms were evaluated at each visit through standardized questionnaire and pooled in a database. On 45th days from the beginning of the lockdown, patients were re-assessed by phone with the same questionnaire. Anxiety and stress levels were assessed through a self-administered online questionnaire based on Generalized Anxiety Disorder 7 test and Perceived Stress Scale 10 test. KEY RESULTS: The intensity-frequency scores of several upper gastrointestinal symptoms improved (Wilcoxon test <0.05). Higher anxiety levels had a higher risk of worsening chest pain (OR 1.3 [1.1-1.7]), waterbrash (OR 1.3 [1.0-1.7]), epigastric burning (OR 1.3 [1.0-1.6]), and abdominal pain (OR 1.6 [1.0-2.3]). When compared to the interval preceding the outbreak, half of the patients declared their symptoms remained unchanged, 13.6% worsened, and 36.4% improved. CONCLUSIONS AND INFERENCES: During the COVID-19 quarantine, there was an improvement of the majority of upper gastrointestinal symptoms in our patients, and anxiety seems an important risk of worsening few of them.

The esophageal mucosal barrier in health and disease: mucosal pathophysiology and protective mechanisms.

Diseases of the esophagus, such as gastroesophageal reflux (GER), can result in changes to mucosal integrity, neurological function, and the microbiome. Although poorly understood, both age and GER can lead to changes to the enteric nervous system. In addition, the esophagus has a distinct microbiome that can be altered in GER. Mucosal integrity is also at risk due to persistent damage from acid. Diagnostic tools, such as ambulatory pH/impedance testing and esophageal mucosal impedance, can assess short-term and longitudinal GER burden, which can also assess the risk for mucosal compromise. The quality of the mucosal barrier is determined by its intercellular spaces, tight junctions, and tight junction proteins, which are represented by claudins, occludins, and adhesion molecules. Fortunately, there are protective factors for mucosal integrity that are secreted by the esophageal submucosal mucous glands and within saliva that are augmented by mastication. These protective factors have potential as therapeutic targets for GER. In this article, we aim to review diagnostic tools used to predict mucosal integrity, aging, and microbiome changes to the esophagus and esophageal mucosal defense mechanisms.

A SIGE-SINGEM-AIGO technical review on the clinical use of esophageal reflux monitoring.

Patients with esophageal symptoms potentially associated with gastroesophageal reflux disease such as heartburn, regurgitation, chest pain, or cough represent one of the most frequent reasons for referral to gastroenterological evaluation. The utility of esophageal reflux monitoring in clinical practice is: (1) to accurately define reflux burden, (2) to segregate patients according to reflux monitoring results as true GERD, reflux hypersensitivity and functional heartburn, and (3) to establish a treatment plan. With this in mind, in the last decade, investigations and technical advances, with the introduction of impedance-pH monitoring and wireless pH capsule, have enhanced our understanding and management of GERD. The following recommendations were discussed and approved after a comprehensive review of the medical literature pertaining to reflux testing techniques and their recent application. This review created under the auspices of the Società Italiana di Gastroenterologia ed Endoscopia Digestiva (SIGE), Società Italiana di Neuro-Gastro-Enterologia e Motilità (SINGEM) and Associazione Italiana Gastroenterologi ed Endoscopisti Digestivi Ospedalieri (AIGO) is intended to help clinicians in applying reflux studies in the most fruitful manner within the context of their patients with esophageal symptoms.

Bile reflux in patients with nerd is associated with more severe heartburn and lower values of mean nocturnal baseline impedance and chemical clearance.

BACKGROUND: Mean nocturnal baseline impedance (MNBI) and postreflux swallow-induced peristaltic wave (PSPW) index are novel impedance-based markers of reflux, but the effect of bile reflux on these metrics is unknown. The aim of this study was to evaluate bile reflux, MNBI, and PSPW index in patients with endoscopy-negative GERD partially responsive to PPI therapy. METHODS: All patients underwent off-PPI endoscopy, esophageal manometry, multichannel intraluminal impedance pH (MII-pH), and bile reflux monitoring. Abnormal esophageal acid exposure time (AET) was required for inclusion. Symptom intensity (using 10-cm visual analog scales), and conventional and novel MII-pH metrics were compared between patients with and without abnormal bile reflux. KEY RESULTS: We evaluated 42 NERD patients (29 males, mean age: 53.4 ± 13. years), mean AET 6.1 ± 2%, of which 21 had abnormal bile reflux (Group A, 10.2 ± 4.9%), and 21 had normal bile reflux (Group B, 0.4 ± 0.1%, P < .05 compared with Group A). Heartburn reporting on PPI was higher in Group A (7.2 ± 2.1 vs 5.8 ± 0.9; P = .002), but AET, number of reflux events (acidic and weakly acidic), did not differ between the two groups. However, both PSPW index and MNBI were lower in Group A (P < .001). A strong inverse linear correlation was found between bile reflux and both MNBI (Pearson's test; R = -0.714; P < .001) and PSPW index (R = -0.722; P < .001). CONCLUSIONS AND INFERENCES: Compared to acid reflux alone, the presence of bile in an acidic esophageal environment is associated with more severe heartburn, lesser relief from PPI therapy, higher impairment of esophageal mucosal integrity and less effective chemical clearance.

Assessment and Diagnostic Accuracy Evaluation of the Reflux Symptom Index (RSI) Scale: Psychometric Properties using Optimal Scaling Techniques.

OBJECTIVES: To investigate the psychometric properties of the reflux symptom index (RSI) as short screening approach for the diagnostic of laryngopharyngeal reflux (LPR) in patients with confirmed diagnosed regarding the 24-hour multichannel intraluminal impedance-pH monitoring (MII-pH). METHODS: From January 2017 to December 2018, 56 patients with LPR symptoms and 71 healthy individuals (control group) were prospectively enrolled. The LPR diagnosis was confirmed through MII-pH results. All subjects (n = 127) fulfilled RSI and the Reflux Finding Score (RFS) was performed through flexible fiberoptic endoscopy. The sensitivity and the specificity of RSI was assessed by ROC (Receiver Operating Characteristic) analysis. RESULTS: A total of 15 LPR patients (26.8%) of the clinical group met MII-pH diagnostic criteria. Among subjects classified as positive for MII- pH diagnoses, RSI and RFS mean scores were respectively 20 (SD ± 10.5) and 7.1 (SD ± 2.5), values not significantly different compared to the negative MII-pH group. The metric analysis of the items led to the realization of a binary recoding of the score. Both versions had similar psychometric properties, α was 0.840 for RSI original version and 0.836 for RSI binary version. High and comparable area under curve (AUC) values indicate a good ability of both scales to discriminate between individuals with and without LPR pathology diagnosis. Based on balanced sensitivity and specificity, the optimal cut-off scores for LPR pathology were ≥ 5 for RSI binary version and ≥ 15 for RSI original version. Both version overestimated LPR prevalence. The original version had more sensitivity and the RSI Binary version had more specificity. CONCLUSIONS: It would be necessary to think about modifying the original RSI in order to improve its sensitivity and specificity (RSI binary version, adding or changing some items), or to introduce new scores in order to better frame the probably affected of LPR patient.

Jackhammer esophagus: A meta-analysis of patient demographics, disease presentation, high-resolution manometry data, and treatment outcomes.

BACKGROUND: Jackhammer esophagus (JE) is a newly described esophageal motility disorder. However, there are limited data on JE and this entity remains misunderstood. METHODS: We performed a systematic review of clinical series on JE through MEDLINE, EMBASE, and Web of Science. Data from included studies were then extracted, and random-effects meta-analyses were performed. RESULTS: Thirty-eight studies met inclusion criteria. The pooled prevalence of JE was 1.97% [95% CI: 1.39%-2.78%] among patients referred for high-resolution manometry (HRM). The mean age at diagnosis was 60.8 years [95% CI: 57.1-64.4] and 65% [95% CI: 58%-72%] of patients were female. JE was significantly more prevalent in postlung transplant patients and morbidly obese patients undergoing HRM (23.99% [95% CI: 9.00%-38.97%] and 5.18% [95% CI: 1.76%-14.3%] respectively). Dysphagia was the most common presentation of JE (64% [95% CI: 52%-77%]) followed by gastroesophageal reflux disease (46% [95% CI: 26%-67%]). The pooled mean distal contractile integral (DCI) of all standard HRM swallows was 9249 mm Hg·s·cm [95% CI: 7834-10 663], and the pooled mean integrated relaxation pressure (IRP) was 13.9 mm Hg [95% CI: 8.2-19.7]. Overall, 73.6% [95% CI: 64.0%-83.1%] of JE patients who underwent treatment achieved clinical symptom improvement (79% [95% CI: 74%-85%] for endoscopic treatment and 63% [95% CI: 47%-79%] for medical treatment). The pooled clinical success rate of peroral endoscopic myotomy (POEM) specifically was 82% [95% CI: 75%-90%]. CONCLUSIONS: JE is a new motility disorder most commonly presenting with dysphagia. High clinical suspicion is important because the diagnosis can only be made through HRM.

Psychiatric Comorbidities and Psychiatric Medication Use Are Highly Prevalent in Patients With Eosinophilic Esophagitis and Associate With Clinical Presentation.

OBJECTIVES: The prevalence of psychiatric disease in patients with eosinophilic esophagitis (EoE) is not fully characterized. We aimed to determine the prevalence of psychiatric disease and centrally acting medication use in a cohort of children and adults with EoE and evaluated whether psychiatric disease affects the EoE clinical presentation. METHODS: We conducted a retrospective study of newly diagnosed cases with EoE at the University of North Carolina from 2002 to 2018. Psychiatric comorbidities and relevant treatments were extracted from the medical records. The demographic and clinical features of patients with EoE with and without psychiatric diagnoses, and those with and without psychiatric medication use, were compared. RESULTS: Of 883 patients (mean age 26.6 years, 68% men, 79% white), 241 (28%) had a psychiatric comorbidity. The most common diagnosis was anxiety (23%) followed by depression (17%); 28% of patients were treated pharmacologically. There were 45 patients (5%) treated pharmacologically without a psychiatric diagnosis for chronic pain syndromes, insomnia, and/or epilepsy. Cases with EoE with a psychiatric diagnosis were more likely to be women, white, and 18 years or older and to have a longer symptom duration before diagnosis. DICUSSION: Psychiatric comorbidities were common in EoE, seen in a third of adults and more than 1 in 7 children, and with similar proportions receiving a prescription medication. These illnesses affected the EoE presentation because psychiatric comorbidities were more likely in older, female, and white patients with a longer duration of symptoms preceding diagnosis.

Evaluation and Validation of the Modified Reflux Symptom Questionnaire-Electronic Diary in Patients With Persistent Gastroesophageal Reflux Disease.

OBJECTIVES: This study aimed to examine the validity of the modified Reflux Symptom Questionnaire-electronic Diary (mRESQ-eD) through patient input and psychometric testing of the questionnaire to support use in clinical trials in patients with persistent gastroesophageal reflux disease (GERD) and in accordance with Food and Drug Administration guidance on patient-reported outcome instruments. METHODS: Cognitive interviews were conducted with patients (n = 30) to evaluate the interpretability and content validity of draft mRESQ-eD items. Patient data from a phase 2b clinical study (ClinicalTrials.gov identifier: NCT02637557) on persistent GERD served to aid in the construction of weekly scores for heartburn severity, regurgitation severity, and total GERD severity. These scores' psychometric properties were also evaluated. RESULTS: Minor modifications were made to the draft mRESQ-eD based on patient feedback to improve interpretability and clarity of the instrument. Psychometric analysis suggested that an 8-item version of the mRESQ-eD was best suited to the clinical data. The internal consistency was found to be high (Coefficient ω = 0.95). Retest reliability and convergent validity were strong for a heartburn weekly severity score, regurgitation weekly severity score, and total GERD severity score. DISCUSSION: The final 8-item mRESQ-eD is a reliable and valid instrument with good psychometric properties for use in clinical trials in patients with persistent GERD. The mRESQ-eD may be considered for inclusion in clinical trials for persistent GERD and potentially positioned, in consultation with Food and Drug Administration, as endpoints to characterize treatment benefit.

Post-reflux swallow-induced peristaltic wave index and mean nocturnal baseline impedance predict PPI response in GERD patients with extra esophageal symptoms.

BACKGROUND: Mean nocturnal baseline impedance (MNBI) and post-reflux swallow-induced peristaltic wave (PSPW) index are able to increase the diagnostic yield of impedance-pH and are associated to proton pump inhibitor (PPI) response. Few data concerning these variables in patients with extra-esophageal symptoms (EES) are available. AIMS: To evaluate, in EES patients, the role of the conventional and new impedance-pH variables in diagnosing GERD and the predictive value of impedance-pH variables for PPI response. METHODS: Consecutive patients presenting suspected GERD-related EES underwent impedance-pH. Patients treated in the last six months with double dose PPI therapy were enrolled. The presence of concomitant typical symptoms was assessed. RESULTS: 239 EES patients were studied; 102 responders and 137 non-responders. Eighty-one (34%) were affected by non-erosive reflux disease (NERD), 61 (26%) presented reflux hypersensitivity (RH) and 97 (40%) were non-GERD. In NERD and RH groups, a significantly higher proportion of patients with pathological PSPW index or MNBI values compared to non-GERD group was observed. 24 (25%) non-GERD patients presented a pathological PSPW index and/or MNBI. Pathological PSPW index, MNBI and presence of typical symptoms were associated to PPI response. CONCLUSIONS: MNBI and PSPW index measurement increases the diagnostic yield of impedance-pH; abnormal values are associated with a satisfactory response to acid-suppressive therapy in EES patients.

Gastroesophageal reflux disease and chronic cough: A possible mechanism elucidated by ambulatory pH-impedance-pressure monitoring.

BACKGROUND: The pathophysiological mechanism(s) of gastroesophageal reflux disease (GERD)-related chronic cough (CC) is unclear. We aimed to determine the mechanism of reflux-induced cough by synchronous monitoring of reflux episodes, esophageal motility, and cough. METHODS: Patients with GERD were prospectively enrolled and classified into GERD with CC (GERD-CC) and without CC (GERD) groups. Twenty-four-hour ambulatory pH-impedance-pressure monitoring was performed; the reflux patterns, esophageal motility during prolonged exposure to acid and characteristics of reflux episodes that induced coughing paroxysms were analyzed. KEY RESULTS: Thirty-one patients with GERD-CC and 47 with GERD were enrolled; all of whose monitoring results fulfilled the criteria for diagnosis of GERD. Patients with GERD-CC had higher reflux symptom scores, longer exposure to acid, higher DeMeester scores, and more frequent reflux episodes, proximal extent reflux detected by impedance, and higher percentage of strongly acidic reflux than patients in the GERD group (all P < .05). Of 63 reflux-cough episodes identified in the GERD-CC group, 74.6% of distal reflux and 67.0% of proximal reflux episodes were acidic. More patients had low pan-esophageal pressure in primary peristalsis (48.5% vs 11.8%, P = .000) and synchronous contraction in secondary peristalsis during prolonged exposure to acid in the GERD-CC than in the GERD group (63.9% vs 9.1%, P = .000). CONCLUSIONS & INFERENCES: Proximal acidic reflux and distal reflux-reflex are jointly associated with reflux-induced cough in patients with GERD. Low pan-esophageal pressure in primary peristalsis and synchronous contraction in secondary peristalsis may play important roles in GERD-associated chronic cough.

Relationship between symptoms during a gastric emptying study and intestinal chemosensitivity with daily symptoms.

BACKGROUND: Non-ulcer dyspepsia (NUD) is a heterogeneous disorder, which is characterized by upper gastrointestinal symptoms and sensorimotor disturbances, including abnormal gastric emptying (GE) and increased intestinal chemosensitivity, and associated with greater plasma glucagon-like peptide-1 (GLP-1) levels during duodenal lipid infusion. However, the relationship(s) between these disturbances and daily symptoms in NUD is variable. We hypothesize that abnormal GE and symptoms during a GE study and during duodenal lipid infusion are associated with the severity of daily symptoms and that GLP-1 mediates symptoms during duodenal lipid infusion in NUD. METHODS: Gastric emptying of solids, symptoms during the GE study and duodenal lipid infusion, and daily gastrointestinal symptoms (2 week diary) were measured in 24 healthy controls and 40 NUD patients. During duodenal lipid infusion, participants received the GLP-1 antagonist exendin 9-39 or placebo. KEY RESULTS: In controls and patients, GE of solids was normal in 75% and 75%, delayed in 8% and 12.5%, or rapid in 17% and 12.5%, respectively. No controls but 26 patients (65%) had severe symptoms during the GE study. During lipid infusion, gastrointestinal symptoms were greater (P = .001) in patients and not affected by exendin. Symptoms during GE study and lipid infusion accounted for respectively 62% and 37% of variance in daily symptom severity. CONCLUSIONS: In NUD, symptoms during a GE study and to a lesser extent during lipid infusion explain the variance in daily symptoms. Intestinal chemosensitivity is not reduced by GLP-1 antagonist. Assessment of symptoms during a GE study may provide a useful biomarker for NUD in research and clinical practice.

Esophageal mucosal innervation in functional heartburn: Closer to healthy asymptomatic subjects than to non-erosive reflux disease patients.

BACKGROUND: Mucosal innervation in non-erosive reflux disease (NERD; pathological esophageal acid exposure, normal macroscopic mucosa) is clearly distinct from that of healthy volunteers (HV) and from patients with esophagitis or Barrett's esophagus: The nerves in NERD are situated much closer to the luminal surface of the mucosa. Patients with functional heartburn (FH) have a similar symptom profile to patients with NERD and indistinguishable macroscopic appearances. However, they have physiological acid exposure and no reflux-symptom association. The aim of our study was to delineate the position of esophageal mucosal nerve fibers in patients with FH and compare it with that in NERD and HV. METHODS: Distal esophageal biopsies from patients with FH were immunohistochemically stained for CGRP. CGRP-positive nerve fibers were identified, and their position relative to the lumen was determined. These results were compared to our previously published cohort of HV and NERD. RESULTS: Eleven patients were included in the FH group with a mean age of 46 years (range 33-69); 7F:4M. Nine patients had visible nerve fibers. The location of the afferent nerve fibers in the distal esophageal mucosa (median of 22, range 10.4-28) was similar to the HV group (median 25.5) and significantly deeper than the superficial nerves seen in NERD (median 9.5). CONCLUSIONS: The mucosal innervation pattern in FH is more alike that of healthy individuals than that of NERD, with afferent nerves lying deep in the mucosa, away from the luminal surface. This supports the theory that heartburn in FH has a distinct nociceptive pathophysiology.

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.

Revisiting Montreal: New Insights into Symptoms and Their Causes, and Implications for the Future of GERD.

The Montreal definition of gastroesophageal reflux disease (GERD) provided a rationale for acid suppression medication without investigation, thus enhancing the management of the substantial symptom burden in these patients. Increased proton-pump inhibitor use has also highlighted their limitations, with one third of "typical" symptoms known to be refractory. Most refractory symptoms are ascribed to reflux hypersensitivity (RH) and functional heartburn (FH). RH may be caused by impaired esophageal mucosal barrier function and sensitization of peripheral esophageal receptors. Central sensitization may also contribute to the perception of non-pathologic reflux in RH, and the perception of physiological stimuli in FH. Importantly, mechanisms underlying GERD, RH, and FH are (in theory) not mutually exclusive, further complicating patient management. Methods used to distinguish GERD from RH and FH are impractical for use in epidemiological studies and pragmatic care and may have limited diagnostic accuracy. This is impeding accurate prevalence estimates and risk factor determination and the identification of new therapies. Direct assessment of mucosal barrier function by measuring impedance is a promising candidate for improved diagnosis. Ultimately though the concept of GERD as a composite, symptom-based entity needs re-evaluation, so that new understandings of upper GI symptoms can direct more precise management.

Randomized clinical trial: a double-blind, placebo-controlled study to assess the clinical efficacy and safety of alginate-antacid (Gaviscon Double Action) chewable tablets in patients with gastro-oesophageal reflux disease.

BACKGROUND: The alginate-antacid Gaviscon Double Action (Gaviscon DA) has a combined acid-neutralizing and reflux-suppressing action. Response to treatment in a symptomatic gastro-oesophageal reflux disease (GERD) population has not yet been tested in a large-scale clinical study. AIM: The aim of this study was to assess the efficacy and safety of Gaviscon DA compared with matched placebo tablets in the reduction of upper gastrointestinal symptoms in patients with GERD. PARTICIPANTS AND METHODS: In this multicentre, randomized, double-blind, placebo-controlled study, adults with GERD symptoms (N=424) received Gaviscon DA or placebo tablets for 7 days. The primary endpoint was a clinically important reduction of at least 1.5 points in the Reflux Disease Questionnaire (RDQ) GERD dimension (combined heartburn/regurgitation) between baseline and the end of the treatment. Secondary endpoints included the change in RDQ score from baseline for individual RDQ dimensions and Overall Treatment Evaluation. RESULTS: A significantly greater proportion of patients treated with Gaviscon DA met the primary endpoint compared with placebo (47.8 vs. 33.2%, respectively, P=0.0031; odds ratio: 1.85, 95% confidence interval: 1.23-2.78). A significant treatment effect was also observed for heartburn, regurgitation and dyspepsia individually. Patients in the Gaviscon DA group rated their overall treatment response greater than patients in the placebo group [mean Overall Treatment Evaluation (SD): 3.2 (3.08) vs. 2.2 (3.34); P<0.001]. No notable differences in the incidence of adverse events were observed between treatments. CONCLUSION: The alginate-antacid combination, Gaviscon DA, is an effective and well-tolerated treatment to reduce reflux symptoms and associated dyspepsia in symptomatic GERD patients.