Review article: the pathophysiology of gastro-oesophageal reflux disease

The Association Between Acidification Time on Wireless Motility Capsule and Gastroesophageal Reflux Disease

BACKGROUND AND AIMS

Gastric physiological characteristics such as fundus accommodation, gastric distention, emptying/transit time, and basal acid output may contribute to the pathogenesis of gastroesophageal reflux disease (GERD). Wireless motility capsule (WMC) uses pH data to determine gastric transit time but has not been used in the evaluation of GERD. Certain metrics such as acidification time, nadir pH, and gastric transit time may provide insight into the mechanisms of GERD related to gastric physiology, allowing WMC to be a complementary tool in the diagnosis of GERD. We aimed to determine whether pH data and transit time on WMC tests correlated with the presence of GERD on ambulatory reflux testing.

STUDY

This was a retrospective study of 28 patients who had undergone both WMC and reflux testing via wireless pH or pH/impedance. Acidification time (time from capsule ingestion to pH<2), nadir postprandial pH, and gastric transit time were manually determined from the WMC capsule proprietary software. Spearman correlation was used to compare these metrics with gastric transit time, percent esophageal acid exposure, and DeMeester score.

RESULTS

Acidification time moderately correlated with gastric transit time, R : 0.44, P =0.02, but not nadir pH, percent esophageal acid exposure, or DeMeester score. Patients with an abnormal reflux test had a significantly longer median acidification time (135.5 vs. 78.5 min, P =0.021). After stratifying by patients with normal versus prolonged gastric transit time, there was a trend toward longer acidification time in patients with positive reflux testing in both groups, but this was not statistically significant. Patients with prolonged gastric transit time >300 minutes were not more likely to have a positive reflux test (38% vs. 35%, P =1).

CONCLUSIONS

The acidification time on WMC was significantly longer in patients with proven GERD and acidification time positively correlated with gastric transit time. Larger studies are needed to determine whether WMC could be used as a complementary tool in investigating patients with GERD symptoms.

Therapeutic Effect of Polaprezinc on Reflux Esophagitis in the Rat Model

BACKGROUND/AIMS

To explore the protective effects and therapeutic mechanism of Esomeprazole (PPI), polaprezinc granule (PZ), and PPI + PZ on reflux esophagitis (RE) in the rat model.

METHODS

Wistar rats were randomly divided into 9 groups, which contain the control group, the acid cessation group (0.7% HCl, Q3D × 4), and the acid persistence group (0.7% HCl, Q3D × 11). PPI was administered by gavage at 8 mg·kg^-1 body weight and PZ was administered by gavage at 120 mg·kg^-1 body weight once a day for 15 days. The gastric cardia tissue of the feeding tube was observed under the light microscope, and the levels of interleukin-8 (IL-8) and prostaglandin E2 (PGE2) were measured by ELISA. The expression of EGFR, Akt, p-Akt, and p-mTOR was detected by Western blot.

RESULTS

The ELISA results showed that the levels of IL-8 and PGE2 were significantly increased in the model group, but decreased in all groups after treatment. In the acid cessation group, PZ treatment had the most significant effect on reducing IL-8 levels and PPI + PZ treatment had the most significant effect on reducing PGE2 levels. In the acid persistence group, the PPI treatment had the most significant effect on reducing the levels of IL-8 and PGE2, and the PZ treatment could also significantly reduce their levels, close to the normal value. Western blot results showed that the expression of PI3K/Akt/mTOR pathway protein was increased in the model group, while its expression was decreased after treatment.

CONCLUSIONS

Polaprezinc has a significant therapeutic effect on RE in rats, which can reduce the levels of IL-8 and PGE2 and downregulate the expression of PI3K/Akt/mTOR signal pathway protein. The efficacy of polaprezinc in the treatment of reflux esophagitis is comparable to that of PPI, and the combination of them is more effective in the reflux esophagitis treatment.

The Effect of Laparoscopic Sleeve Gastrectomy With Concomitant Hiatal Hernia Repair on Gastroesophageal Reflux Disease

AIM

The aim of this study is to reveal incidence of gastroesophageal reflux disease (GERD) after laparoscopic sleeve gastrectomy (LSG) and to determine the effect of LSG with hiatal hernia repair on GERD.

METHODS

A total of 440 patients, 395 of them underwent primary LSG (group A) and 45 of them underwent LSG with concomitant hiatal hernia repair (group B) between March 2018 and September 2020 were included in the study. Presence of hiatal hernia was evaluated with endoscopy and confirmed intraoperatively. Patients were evaluated for GERD symptoms in the pre and postoperative period. Two groups' data were compared.

RESULTS

Mean age of the 440 patients was 38.4±11 years (56% female) and mean body mass index was 44.2±7 kg/m2. Symptomatic GERD was detected in 103 (23.4%) and hiatal hernia was detected in 45 (10.2%) patients. İn the preoperative assessment there was no difference with regard to demographics and symptomatic GERD between the 2 groups. Mean duration of follow-up was 17±5.7 (12 to 28) months in the overall study population. Mean body mass index decreased to 28.3±4.9 kg/m2at 12 months after LSG. Excess weight loss ratio was found to be 81±20.4%. The rate of symptomatic GERD after LSG in group A was found to be 20% (n=79/395). Of these patients, 46 (11.6%) had de novo GERD and 33 (38%) had persistent GERD. GERD resolved completely in 54 (62%) patients. In the group B, the rate of symptomatic GERD was detected as 33% (n=15/45) (P=0.04). The rate of de novo GERD (20%) was also higher in group B (P=0.03). The rate of persistent GERD (37%) and GERD resolution (62%) were similar in both groups.

CONCLUSION

İn our study, symptomatic and de novo GERD rates were detected to be higher in the LSG+HH group than LSG alone.

How effective is laparoscopic redo-antireflux surgery?

BACKGROUND

The failure-rate after primary antireflux surgery ranges from 3 to 30%. Reasons for failures are multifactorial. The aim of this study is to gain insight into the complex reasons for, and management of, failure after antireflux surgery.

METHODS

Patients were selected for redo-surgery after a diagnostic workup consisting of history and physical examination, upper gastrointestinal endoscopy, quality-of-life assessment, screening for somatoform disorders, esophageal manometry, 24-hour-pH-impedance monitoring, and selective radiographic studies such as Barium-sandwich for esophageal passage and delayed gastric emptying. Perioperative and follow-up data were compiled between 2004 and 2017.

RESULTS

In total, 578 datasets were analyzed. The patient cohort undergoing a first redo-procedure (n = 401) consisted of 36 patients after in-house primary LF and 365 external referrals (mean age: 62.1 years [25-87]; mean BMI 26 [20-34]). The majority of patients underwent a repeated total or partial laparoscopic fundoplication. Major reasons for failure were migration and insufficient mobilization during the primary operation. With each increasing number of required redo-operations, the complexity of the redo-procedure itself increased, follow-up quality-of-life decreased (GIQLI: 106; 101; and 100), and complication rate increased (intraoperative: 6,4-10%; postoperative: 4,5-19%/first to third redo). After three redo-operations, resections were frequently necessary (morbidity: 42%).

CONCLUSIONS

Providing a careful patient selection, primary redo-antireflux procedures have proven to be highly successful. It is often the final chance for a satisfying result may be achieved upon performing a second redo-procedure. A third revision may solve critical problems, such as severe pain and/or inadequate nutritional intake. When resection is required, quality of life cannot be entirely normalized.

Primary laparoscopic fundoplication in selected patients with gastroesophageal reflux disease

BACKGROUND

Despite proton pump inhibitors being a powerful therapeutic tool, laparoscopic fundoplication (LF) has proven successful in the treatment of gastroesophageal reflux disease (GERD), through mechanical augmentation of a weak antireflux barrier and the advantages of minimally invasive access. A critical patient selection for LF, based on thorough preoperative assessment, is important for the management of GERD-patients. The purpose of this study is to provide an overview on the management of GERD-patients treated by primary LF in a specialized center and to illustrate the possible outcome after several years.

METHODS

Patients were selected after going through diagnostic workup consisting of patient's history and physical examination, upper gastrointestinal endoscopy, assessment of gastrointestinal Quality of Life Index, screening for somatoform disorders, functional assessment by esophageal manometry, (impedance)-24-hour-pH-monitoring, and selective radiographic studies. The indication for LF was based on EAES-guidelines. Either a floppy and short Nissen fundoplication was performed or a posterior Toupet-hemifundoplication was chosen. A long-term follow-up assessment was attempted after surgery.

RESULTS

In total, n = 1131 patients were evaluated (603 males; 528 females; mean age; 48.3 years; and mean body mass index: 27). The mean duration between onset of symptoms and surgery was 8 years. Nissen: n = 873, Toupet: n = 258; conversion rateerativ: 0.5%; morbidity 4%, mortality: 1 (1131). Mean follow-up (n = 898; 79%): 5.6 years; pre/post-op results: esophagitis: 66%/12.1%; Gastrointestinal Quality of Life Index: median: 92/119; daily proton pump inhibitors-intake after surgery: 8%; and operative revisions 4.3%.

CONCLUSIONS

In conclusion, our data show that careful patient selection for laparoscopic fundoplication and well-established technical concepts of mechanical sphincter augmentation can provide satisfying results in the majority of patients with severe GERD.

Clinical use of mean nocturnal baseline impedance and post-reflux swallow-induced peristaltic wave index for the diagnosis of gastro-esophageal reflux disease

The clinical diagnosis of gastro-esophageal reflux disease (GERD) is based on the presence of typical esophageal troublesome symptoms. In clinical practice, heartburn relief following a proton pump inhibitor (PPI) trial or endoscopy can confirm a diagnosis of GERD. In cases of diagnostic uncertainty or before anti-reflux interventions, combined impedance-pH monitoring (MII-pH) provides a comprehensive assessment of both physical and chemical properties of the refluxate, allowing to achieve a conclusive diagnosis of GERD. Recently, the Lyon Consensus proposed the use of mean nocturnal baseline impedance (MNBI) and post-reflux swallow-induced peristaltic wave index (PSPW-I) as novel MII-pH metrics to support the diagnosis of GERD. The calculation of MNBI and PSPW-I currently needs to be performed manually, but artificial intelligence systems for the automated analysis of MII-pH tracings are being developed. Several studies demonstrated the increased diagnostic yield MNBI and PSPW-I for the categorization of patients with GERD at both on- and off-PPI MII-pH monitoring. Accordingly, we performed a narrative review on the clinical use and diagnostic yield of MNBI and PSPW-I when the diagnosis of GERD is uncertain. Based on currently available evidence, we strongly support the evaluation of PSPW-I and MNBI as part of the standard assessment of MII-pH tracings for the evaluation of GERD, especially in patients with endoscopy-negative heartburn.

Pathophysiology of gastroesophageal reflux disease-which factors are important?

Background

Pathophysiology of gastroesophageal reflux disease (GERD) shows a multifactorial background. Different anatomical and functional alterations can be determined such as weakness of the lower esophageal sphincter (LES), changes in anatomy by a hiatal hernia (HH), an impaired esophageal motility (IEM), and/or an associated gastric motility problem with either duodeno-gastro-esophageal reflux (DGER) or delayed gastric emptying (DGE). The purpose of this study is to assess a large GERD-patient population to quantitatively determine different pathophysiologic factors contributing to the disease.

Methods

For this analysis only patients with documented GERD (pathologic esophageal acid exposure) were selected from a prospectively maintained databank. Investigations: history and physical, body mass index, endoscopy, esophageal manometry, 24 h-pH-monitoring, 24 h-bilirbine-monitoring, radiographic-gastric-emptying or scintigraphy, gastrointestinal quality of life index (GIQLI).

Results

In total, 728 patients (420 males; 308 females) were selected for this analysis. Mean age: 49.9 years; mean BMI: 27.2 kg/m² (range, 20-45 kg/m²); mean GIQLI of 91 (range: 43-138; normal level: 121); no esophagitis: 30.6%; minor esophagitis (Savary-Miller type 1 or Los Angeles Grade A): 22.4%; esophagitis [2-4]/B-D: 36.2%; Barrett's esophagus 10%. Presence of pathophysiologic factors: HH 95.4%; LES-incompetence 88%, DGER 55%, obesity 25.6%, IEM 8.8%, DGE 6.8%.

Conclusions

In our evaluation of GERD patients, the most important pathophysiologic components are anatomical alterations (HH), LES-incompetence and DGER.

Severity of GERD and disease progression

BACKGROUND

Many factors may play a role in the severity and progression of gastroesophageal reflux disease (GERD) since pathophysiology is multifactorial. Data regarding the progression of GERD are controversial: some reports of increased esophageal acid exposure (EAE) and mucosal damage were considered as evidence for a stable disease course, while others interprete these findings as disease progression. The aim of this study is to analyze a large patient-population with persisting symptoms indicative of GERD under protonpumpinhibitor-therapy and identify components characterizing disease severity and progression.

METHODS

Patients with symptoms indicative of GERD were included in the study in a tertiary referral center (Frankfurt, Germany). All selected patients were under long-term protonpumpinhibitor-therapy with persistant symptoms. All patients underwent investigations to collect data on their physical status, EAE, severity of esophagitis, anatomical changes, and esophageal functional defects as well as their relation to the duration of the disease. Incidence over time was plotted as survival curves and tested with Log-rank tests for the four main disease markers. Multivariate modeling with COX-regression model was used to estimate the general impact of the four main disease markers on the time course of the disease. In order to elucidate possible causal relationships over time, a path analysis (structural equation model) was calculated.

RESULTS

From the database with 1480 data sets, 972 patients were evaluated (542 males, 430 females). The mean age was 50.5 years (range18-89). The mean body mass index was 27.2(19-48). The mean time between the onset of symptoms and the diagnostic investigations was 8.2 years (1-50). A longer disease history for GERD was significantly associated with a higher risk for LES-incompetence. The mean duration from symptom onset to the time of clinical investigation was 9 years for patients with LES-incompetence (n = 563), compared to a mean of 6 years for those with mechanically intact LES (n = 95). A longer period from symptom onset to diagnostics was significantly associated with higher acid exposure. The pathway analysis was significant for the following model: 'history' (P < 0.001➔LES-incompetence & Hiatal Hernia➔(p < 0,001)➔pH-score (P < 0.001).Conclusion: LES-incompetence, the functional deterioration of the LES, and the anatomical alteration at the esophagogastric junction (Hiatal Hernia) as well as an increased EAE were associated with a long history of suffering from GERD. Path modeling suggests a causal sequence overtime of the main disease-parameters, tentatively allowing for a prediction of the course of the disease.

Recent insights into the biology of Barrett's esophagus

Barrett's esophagus (BE) is the only known precursor to esophageal adenocarcinoma (EAC), an aggressive cancer with a poor prognosis. Our understanding of the pathogenesis and Barrett's metaplasia is incomplete, and this has limited the development of new therapeutic targets and agents, risk stratification ability, and management strategies. This review outlines current insights into the biology of BE and addresses controversies surrounding cell of origin, cellular reprogramming theories, updates on esophageal epithelial barrier function, and the significance of goblet cell metaplasia and its association with malignant change. Further research into the basic biology of BE is vital as it will underpin novel therapies and improve our ability to predict malignant progression and help identify the minority of patients who will develop EAC.

Evidence for Cytoprotective Effect of Carbon Monoxide Donor in the Development of Acute Esophagitis Leading to Acute Esophageal Epithelium Lesions

Exposure to acidic gastric content due to malfunction of lower esophageal sphincter leads to acute reflux esophagitis (RE) leading to disruption of esophageal epithelial cells. Carbon monoxide (CO) produced by heme oxygenase (HMOX) activity or released from its donor, tricarbonyldichlororuthenium (II) dimer (CORM-2) was reported to protect gastric mucosa against acid-dependent non-steroidal anti-inflammatory drug-induced damage. Thus, we aimed to investigate if CO affects RE-induced esophageal epithelium lesions development. RE induced in Wistar rats by the ligation of a junction between pylorus and forestomach were pretreated i.g. with vehicle CORM-2; RuCl₃; zinc protoporphyrin IX, or hemin. CORM-2 was combined with NG-nitro-L-arginine (L-NNA), indomethacin, capsazepine, or capsaicin-induced sensory nerve ablation. Esophageal lesion score (ELS), esophageal blood flow (EBF), and mucus production were determined by planimetry, laser flowmetry, histology. Esophageal Nrf-2, HMOXs, COXs, NOSs, TNF-α and its receptor, IL-1 family and IL-1 receptor antagonist (RA), NF-κB, HIF-1α, annexin-A1, suppressor of cytokine signaling (SOCS3), TRPV1, c-Jun, c-Fos mRNA/protein expressions, PGE₂, 8-hydroxy-deoxyguanozine (8-OHdG) and serum COHb, TGF-β1, TGF-β2, IL-1β, and IL-6 content were assessed by PCR, immunoblotting, immunohistochemistry, gas chromatography, ELISA or Luminex platform. Hemin or CORM-2 alone or combined with L-NNA or indomethacin decreased ELS. Capsazepine or capsaicin-induced denervation reversed CORM-2 effects. COHb blood content, esophageal HMOX-1, Nrf-2, TRPV1 protein, annexin-A1, HIF-1α, IL-1 family, NF-κB, c-Jun, c-Fos, SOCS3 mRNA expressions, and 8-OHdG levels were elevated while PGE₂ concentration was decreased after RE. CO donor-maintained elevated mucosal TRPV1 protein, HIF-1 α, annexin-A1, IL-1RA, SOCS3 mRNA expression, or TGF-β serum content, decreasing 8-OHdG level, and particular inflammatory markers expression/concentration. CORM-2 and Nrf-2/HMOX-1/CO pathway prevent esophageal mucosa against RE-induced lesions, DNA oxidation, and inflammatory response involving HIF-1α, annexin-A1, SOCS3, IL-1RA, TGF-β-modulated pathways. Esophagoprotective and hyperemic CO effects are in part mediated by afferent sensory neurons and TRPV1 receptors activity with questionable COX/PGE₂ or NO/NOS systems involvement.

Pathophysiology, diagnosis, and pharmacological treatment of gastro-esophageal reflux disease

INTRODUCTION

Gastro-esophageal reflux disease (GERD) is a highly prevalent, chronic, relapsing disorder, whose knowledge has increased in last years thanks to the advent of new sophisticated techniques, such as 24-h impedance-pH monitoring and high-resolution manometry, for the study of esophageal functions.

AREAS COVERED

This review provides an overview of our advancements in understanding the complex pathophysiology, improving the diagnosis and defining the modern pharmacological therapeutic approach to GERD.

EXPERT OPINION

The growing clinical application of impedance-pH testing has allowed us to know the diversity of patients with non-erosive reflux disease (NERD), who nowadays represent about 70% of the whole population with reflux symptoms. We have realized that NERD has to be considered as an umbrella term covering various subgroups with different pathophysiologies. The development of new impedance metrics, in particular mean nocturnal baseline impedance, seems to be promising in the improvement of the diagnostic process of this disease. There are no particularly innovative features in the pharmacological therapy of GERD, unless the interest toward drugs is able to increase the defense properties of esophageal mucosa and/or its protection. These compounds can be of help in combination with proton pump inhibitors in NERD patients with partial response to antisecretory drugs alone.

Melatonin in Prevention of the Sequence from Reflux Esophagitis to Barrett's Esophagus and Esophageal Adenocarcinoma: Experimental and Clinical Perspectives

Melatonin is a tryptophan-derived molecule with pleiotropic activities which is produced in all living organisms. This "sleep" hormone is a free radical scavenger, which activates several anti-oxidative enzymes and mechanisms. Melatonin, a highly lipophilic hormone, can reach body target cells rapidly, acting as the circadian signal to alter numerous physiological functions in the body. This indoleamine can protect the organs against a variety of damaging agents via multiple signaling. This review focused on the role played by melatonin in the mechanism of esophagoprotection, starting with its short-term protection against acute reflux esophagitis and then investigating the long-term prevention of chronic inflammation that leads to gastroesophageal reflux disease (GERD) and Barrett's esophagus. Since both of these condition are also identified as major risk factors for esophageal carcinoma, we provide some experimental and clinical evidence that supplementation therapy with melatonin could be useful in esophageal injury by protecting various animal models and patients with GERD from erosions, Barrett's esophagus and neoplasia. The physiological aspects of the synthesis and release of this indoleamine in the gut, including its release into portal circulation and liver uptake is examined. The beneficial influence of melatonin in preventing esophageal injury from acid-pepsin and acid-pepsin-bile exposure in animals as well as the usefulness of melatonin and its precursor, L-tryptophan in prophylactic and supplementary therapy against esophageal disorders in humans, are also discussed.

Pathophysiology of Gastroesophageal Reflux Disease

Gastroesophageal reflux disease pathophysiology is multifactorial and linked to a misbalance between the aggressiveness of the refluxate into the esophagus or adjacent organs and the failure of protective mechanisms associate or not to a defective valvular mechanism at the level of the esophagogastric junction incapable of dealing with a transdiaphragmatic pressure gradient. Antireflux mechanisms include the lower esophageal sphincter and abdominal esophagus, the diaphragm, the angle of His, the Gubaroff valve, and the phrenoesophageal membrane. Protective mechanisms include esophageal motility, saliva production, and epithelial protection. Disruption of this balance occurs most commonly due to the presence of a hiatal hernia, esophageal dysmotility, a rise in abdominal pressure (obesity), and decrease in thoracic pressure (chronic lung diseases).

A review of pharmacotherapy for treating gastroesophageal reflux disease (GERD)

INTRODUCTION

Medical therapy of gastroesophageal reflux disease (GERD) is based on the use of proton pump inhibitors (PPIs) as first choice treatment. Despite their effectiveness, about 20-30% of patients report an inadequate response and alternative drugs are required. Areas covered: This review provides an overview of current pharmacotherapy for treating GERD by showing the results of PPIs, reflux inhibitors, antidepressants and mucosa protective medications. Expert opinion: Medical therapy of GERD does not definitely cure the disease, because even PPIs are not able to change the key factors responsible for it. However, they remain the mainstay of medical treatment, allowing us to alleviate symptoms, heal esophagitis and prevent complications in the majority of cases. Nevertheless, many patients do not respond, because acid does not play any pathogenetic role. Prokinetics and reflux inhibitors have the potential to control motor abnormalities, but the results of clinical trials are inconsistent. Antidepressant drugs are effective in specific subgroups of NERD patients with visceral hypersensitivity, but larger, controlled clinical studies are necessary. Protective drugs or medical devices have been recently adopted to reinforce mucosal resistance and preliminary trials have confirmed their efficacy either combined with or as add-on medication to PPIs in refractory patients.

A Double-blind, Randomized, Multicenter Clinical Trial Investigating the Efficacy and Safety of Esomeprazole Single Therapy Versus Mosapride and Esomeprazole Combined Therapy in Patients with Esophageal Reflux Disease

Background/Aims

We aim to evaluate the efficacy and safety of combination therapy in erosive reflux disease (ERD) patients by comparing endoscopic healing rates according to the Los Angeles classification for esomeprazole alone, and esomeprazole plus mosapride.

Methods

A total of 116 ERD patients were randomized to receive esomeprazole 40 mg once daily plus mosapride 5 mg 3 times daily (E+M group), or esomeprazole plus placebo (E only group) for 8 weeks. Patients recorded gastroesophageal reflux disease (GERD) symptom questionnaire at weeks 4 and 8. The primary endpoint was the endoscopic healing rate of ERD after 8 weeks of treatment.

Results

Endoscopic healing rates according to the Los Angeles classification was 32 (66.7%) in the E+M group and 26 (60.5%) in the E only group, but there was no statistically significant difference between the groups. Only at 4 weeks, the total GERD symptom score changes relative to the baseline significantly improved in the E+M group than that of the E only group (−13.4 ± 14.7 vs −8.0 ± 12.3, P = 0.041), and upper abdominal pain and belching score changes showed significantly improved in the E+M group than that of the E only group (P = 0.018 and P = 0.013, respectively).

Conclusions

The combination of a proton pump inhibitor with mosapride shows a tendency for upper abdominal pain, belching, and total GERD symptoms scores to improve more rapidly. This suggests that combination therapy with esomeprazole and mosapride will be useful for rapid improvement of specific GERD symptoms, such as upper abdominal pain and belching in ERD patients.

Incidence of postoperative nausea and vomiting following gynecological laparoscopy: A comparison of standard anesthetic technique and propofol infusion

OBJECTIVE

To determine the safety, efficacy, and feasibility of propofol-based anesthesia in gynecological laparoscopies in reducing incidences of postoperative nausea and vomiting compared to a standard anesthesia using thiopentone/isoflurane.

DESIGN

Randomized single-blind (for anesthesia techniques used) and double-blind (for postoperative assessment) controlled trial.

SETTING

Operation theater, postanesthesia recovery room, teaching hospital.

PATIENTS

Sixty ASA (American Society of Anesthesiologists) I and II female patients (aged 20-60 years) scheduled for gynecological laparoscopy were included in the study.

INTERVENTIONS

Patients in Group A received standard anesthesia with thiopentone for induction and maintenance with isoflurane-fentanyl, and those in Group B received propofol for induction and maintenance along with fentanyl. All patients received nitrous oxide, vecuronium, and neostigmine/glycopyrrolate. No patient received elective preemptive antiemetic, but patients did receive it after more than one episode of vomiting.

MEASUREMENTS

Assessment for incidence of postoperative nausea and vomiting as well as other recovery parameters were carried out over a period of 24 hours.

MAIN RESULTS

Six patients (20%) in Group A and seven patients (23.3%) in Group B experienced nausea. Two patients (6.66%) in Group B had vomiting versus 12 (40%) in Group A (p<0.05). Overall, the incidence of emesis was 60% and 30% in Groups A and B, respectively (p<0.05). All patients in Group B had significantly faster recovery compared with those in Group A. No patient had any overt cardiorespiratory complications.

CONCLUSION

Propofol-based anesthesia was associated with significantly less postoperative vomiting and faster recovery compared to standard anesthesia in patients undergoing gynecological laparoscopy.

Effects of Metoclopramide on Esophageal Motor Activity and Esophagogastric Junction Compliance in Healthy Volunteers

Background/Aims

Prokinetic drugs such as metoclopramide are frequently used as second-line therapy for patients with gastroesophageal reflux disease. However, their beneficial effects remain unclear. Esophageal motor activities and compliance of the esophagogastric junction (EGJ) are important for prevention of gastroesophageal reflux. Although metoclopramide has been reported to increase lower esophageal sphincter (LES) pressure, its effects on EGJ compliance have not been evaluated. In the present study, we investigated the effects of metoclopramide on esophageal motor activities and EGJ compliance.

Methods

Nine healthy male volunteers without abdominal symptoms were enrolled. Peristaltic esophageal contractions and LES pressure were examined using high-resolution esophageal manometry, while EGJ compliance was evaluated with an endoluminal functional lumen-imaging probe. After obtaining baseline values for esophageal motor activities and EGJ compliance, metoclopramide (10 mg) was intravenously administered, then all measurements were repeated at 15 minutes after administration in each subject.

Results

Following administration of metoclopramide, mean resting LES pressure was significantly increased as compared with the baseline (13.7 ± 9.2 vs 26.7 ± 8.8 mmHg, P < 0.05). In addition, metoclopramide significantly augmented peristaltic contractions, especially in the distal esophageal segment (P < 0.05). On the other hand, distensibility index did not change after administration (4.5 ± 0.5 vs 4.1 ± 0.5 mm²/mmHg), suggesting no significant effect of metoclopramide on EGJ compliance.

Conclusions

Metoclopramide augmented esophageal contractions without changing EGJ compliance in healthy adults.

Calculation of esophagogastric junction vector volume using three-dimensional high-resolution manometry

Lower esophageal sphincter vector volume (V-V) was developed in the late 1980s by Bombeck, as a quantification of sphincter integrity used to select reflux patients with a defective valve who may benefit from surgery. Its calculation required motorized pull-through of an 8-lumen water perfused manometry catheter with subsequent computerized reconstruction of sphincter morphology. Recently, a three-dimensional high-resolution manometry (3D-HRM) assembly (Given Imaging, Duluth, GA, USA) has been developed with the potential to assess real-time V-V. The aim of this study was to assess the feasibility of the calculation of V-V using the 3D-HRM assembly and to compare measures of its value using real-time 3D-HRM to simulated analogous measures. Eight asymptomatic controls (4F, ages 26-49) were studied in a supine position with a solid-state 3D-HRM assembly positioned across the esophagogastric junction (EGJ). The 9-cm 3D segment comprised 12 rings of 8 radially dispersed pressure sensors, each 2.5 mm long and spaced 7.5 mm apart on center. Recordings were done during normal respiration: (i) with the 3D-HRM segment in a stationary position across the EGJ; and (ii) during a station pull-through of the 3D-HRM segment withdrawing it across the EGJ at 5-mm increments with each position held for 30 seconds. EGJ cross-sectional vector areas (CSVAs) were computed using the irregular polygon area formula: [Formula in text], and n = 8 radial sensors. V-V was computed as the sum of CSVAs at inspiration and end-expiration by three methods: real-time 3D-HRM, three-station composite, and single-sensor ring measurements. There were no statistic differences among the methods, and all methods showed significant differences between inspiration and expiration. Calculation of real-time V-V is feasible using the 3D-HRM. Moreover, the results of this study highlighted the potential primary role of the diaphragmatic hiatus in the pathophysiology of gastroesophageal reflux disease and the underrecognized but crucial role of the crural repair during the antireflux surgery.

Review of gastroesophageal reflux disease (GERD) in the diabetic patient

This article reviews the known pathophysiological mechanisms of comorbid gastroesophageal reflux disease (GERD) in the diabetic patient, discusses therapeutic options in care, and provides an approach to its evaluation and management. We searched for review articles published in the past 10 years through a PubMed search using the filters diabetes mellitus, GERD, pathophysiology, and management. The search only yielded a handful of articles, so we independently included relevant studies from these review articles along with related citations as suggested by PubMed. We found diabetic patients are more prone to developing GERD and may present with atypical manifestations. A number of mechanisms have been proposed to elucidate the connection between these two diseases. Studies involving treatment options for comorbid disease suggest conflicting drug-drug interactions. Currently, there are no published guidelines specifically for the evaluation and management of GERD in the diabetic patient. Although there are several proposed mechanisms for the higher prevalence of GERD in the diabetic patient, this complex interrelationship requires further research. Understanding the pathophysiology will help direct diagnostic evaluation. In our review, we propose a management algorithm for GERD in the diabetic patient.

Drug treatment of pruritus in liver diseases

Pruritus (itch) is a common complication of cholestatic liver diseases (CLD). It can be a distressing and debilitating symptom, causing significant impairment in quality of life. Treatment of pruritus in liver diseases can be challenging and requires specific management with early initiation and a step-wise approach using specific drugs. Clinical trials are ongoing with novel agents that demonstrate potential efficacy. Patients with cholestatic pruritus are likely to present to a variety of clinicians who would benefit from medical awareness of available treatment options. In this review, we outline the pharmaceutical agents currently used to treat cholestatic pruritus and provide the evidence base for targeted symptom control of itch in liver diseases. We also highlight recent developments in the pathophysiology of cholestatic pruritus and the emerging novel therapies.

Predictive value of routine esophageal high-resolution manometry for gastro-esophageal reflux disease

BACKGROUND

Using conventional manometry, gastro-esophageal reflux disease (GERD) was associated with a reduced lower esophageal sphincter (LES) pressure and impaired peristalsis. However, with a large overlap between GERD patients and controls, these findings are of limited clinical relevance. It is uncertain whether the more detailed information of high-resolution manometry (HRM) can discriminate GERD patients. Therefore, we aimed to determine to which extent HRM findings can predict GERD.

METHODS

HRM measurements in 69 patients with GERD and 40 healthy subjects were compared and the predictive value of HRM for the diagnosis of GERD was explored.

KEY RESULTS

GERD patients had a significantly lower contraction amplitude (55 vs 64 mmHg; p = 0.045) and basal LES pressure (10 vs 13.2 mmHg; p = 0.034) than healthy controls. GERD patients more often had a hiatal hernia than healthy subjects (30% vs 7%; p = 0.005). Patients with reflux esophagitis had a lower DCI than patients without reflux esophagitis (558 vs 782 mmHg cm s; p = 0.045). No significant difference was seen in contractile front velocity, distal latency, number of peristaltic breaks, residual LES pressure and LES length. On multivariate logistic regression analysis, both esophagogastric junction type I (OR 4.971; 95% CI 1.33-18.59; p = 0.017) and mean wave amplitude (OR 0.95; 95% CI 0.90-0.98; p = 0.013) were found to be independent predictors of GERD. However, the sensitivity and specificity of these findings were low.

CONCLUSIONS & INFERENCES

Hiatal hernia, low contraction amplitude and LES pressure are associated with GERD, but do not predict the disease with sufficient accuracy. Routine esophageal HRM can therefore not be used to distinguish GERD patients from healthy subjects.

The Role of Gastroesophageal Reflux and Other Factors during Progression to Esophageal Adenocarcinoma

BACKGROUND

U.S. esophageal adenocarcinoma (EAC) incidence increased over 5-fold between 1975 and 2009. Symptomatic gastroesophageal reflux disease (sGERD) elevates the risk for EAC. However, a simple calculation suggests that changes in sGERD prevalence can explain at most approximately 16% of this trend. Importantly, a mechanistic understanding of the influence of sGERD and other factors (OF) on EAC is lacking.

METHODS

A multiscale model was developed to estimate temporal trends for sGERD and OF, and their mechanistic role during carcinogenesis. Model calibration was to Surveillance, Epidemiology, and End Results (SEER) incidence and age-dependent sGERD data using maximum likelihood and Markov chain Monte Carlo (MCMC) methods.

RESULTS

Among men, 77.8% [95% credibility interval (CI), 64.9%-85.6%] of the incidence trend is attributable to OF, 13.4% (95% CI, 11.4%-17.3%) to sGERD, and 8.8% (95% CI, 4.2%-13.7%) to sGERD-OF interactions. Among women, 32.6% (95% CI, 27.0%-39.9%) of the trend is attributable to OF, 13.6% (95% CI, 12.5%-15.9%) to sGERD, and 47.4% (95% CI, 30.7%-64.6%) to interactions. The predicted trends were compared with historical trends for obesity, smoking, and proton pump inhibitor use. Interestingly, predicted OF cohort trends correlated most highly with median body mass index (BMI) at age 50 (r = 0.988 for men; r = 0.998 for women).

CONCLUSIONS

sGERD and OF mechanistically increase premalignant cell promotion, which increases EAC risk exponentially with exposure duration.

IMPACT

Surveillance should target individuals with long-duration sGERD and OF exposures.

Impact of hiatal hernia on pediatric dyspeptic symptoms

OBJECTIVES

Hiatal hernia (HH) affects from 10% to 50% of adult population. The correlation between HH, gastroesophageal reflux disease, dyspeptic symptoms, and esophagitis has long been known in adults. The primary objective of our prospective observational study was to estimate the prevalence of HH in children undergoing esophagogastroduodenoscopy (EGD), irrespective of their symptoms.

METHODS

We prospectively enrolled 111 consecutive children (48 boys and 63 girls; mean age 94.9 ± 52.3 months) referred for EGD. In all of the patients a symptomatic score assessment based on the Rome III criteria was used to measure frequency, severity, and duration of gastrointestinal symptoms. HH presence was endoscopically defined; esophagitis presence was evaluated either endoscopically and histologically. Children were divided in 2 age-range groups: <48 months (group 1) and >48 months (group 2).

RESULTS

Twenty-three patients of 111 (20.7%) had evidence of a sliding HH at EGD. In children from group 2, we found a statistically significant association of HH with heartburn (P = 0.03, 95% confidence interval 1-9.3, r = 0.1) and regurgitation (P = 0.003, 95% confidence interval 1.7-20.4, r = 0.3). Regarding esophagitis presence, no association was found at any age either with defined esophagitis or with dilated intercellular spaces.

CONCLUSIONS

Prevalence of HH in our study population was 20.7%. According to our data, HH correlates with the presence of heartburn and regurgitation in children, but not in toddlers. No association was found with esophagitis at any age.

Effects of baclofen on the functional anatomy of the oesophago-gastric junction and proximal stomach in healthy volunteers and patients with GERD assessed by magnetic resonance imaging and high-resolution manometry: a randomised controlled double-blind study

BACKGROUND

The mechanism of reflux protection may involve a 'flap valve' at the oesophago-gastric junction (OGJ).

AIM

To assess the effects of baclofen, a gamma-aminobutyric acid receptor type-B (GABA-B) agonist known to suppress reflux events, on the 'functional anatomy' of the OGJ and proximal stomach after a large test meal.

METHODS

Twelve healthy volunteers (HVs) and 12 patients with gastro-oesophageal reflux disease (GERD); with erosive oesophagitis or pathological oesophageal acid exposure completed a randomised, double-blind, cross-over study. On 2 test days participants received 40-mg baclofen or placebo before ingestion of a large test meal. OGJ structure and function were assessed by high-resolution manometry (HRM) and magnetic resonance imaging (MRI) using validated methods. Measurements of the oesophago-gastric angle were derived from three-dimensional models reconstructed from anatomic MRI images. Cine-MRI and HRM identified postprandial reflux events. Mixed model analysis and Wilcoxon rank signed tests assessed differences between participant groups and treatment conditions.

RESULTS

In both HVs and GERD patients, baclofen reduced the frequency of postprandial reflux events. The oesophago-gastric insertion angle in GERD patients was reduced (-4.1 ± 1.8, P = 0.025), but was unchanged in healthy controls. In both study groups, baclofen augmented lower oesophageal sphincter (LES) pressure (HVs: +7.3 ± 1.8 mmHg, P < 0.0001, GERD: +4.50 ± 1.49 mmHg, P < 0.003) and increased LES length (HVs: +0.48 ± 0.11 cm, P < 0.0003, GERD: +0.35 ± 0.06 cm, P < 0.0001).

CONCLUSIONS

Baclofen inhibits transient LES relaxations and augments LES pressure and length. Additionally, baclofen has effects on the 'functional anatomy' of the OGJ and proximal stomach in GERD patients, which may suppress reflux by means of a 'flap valve' mechanism.

The effects of baclofen for the treatment of gastroesophageal reflux disease: a meta-analysis of randomized controlled trials

Objectives. Baclofen can relieve gastroesophageal reflux-related symptoms in healthy subjects and gastroesophageal reflux disease (GERD) patients by reducing the incidence of transient lower esophageal sphincter relaxation. This meta-analysis aimed to evaluate the efficacy and safety of baclofen for the treatment of GERD. Methods. We systematically searched randomized controlled trials published prior to November 2013 from PubMed, Medline, Embase, ScienceDirect, ClinicalTrials.gov, and the Cochrane Central Register of Randomized Controlled Trials. We performed a meta-analysis of all eligible trials. Results. Nine studies were identified with a total of 283 GERD patients and healthy subjects. Comparative analysis provided high quality data supporting the ability of baclofen to promote a short-term decrease in the number of reflux episodes per patient, the average length of reflux episodes, and the incidence of transient lower esophageal sphincter relaxation. No serious adverse events or death events were reported, and there were no significant differences in the overall adverse events between baclofen and placebo. All reported side effects of baclofen were of mild-to-moderate intensity, and the drug was well tolerated. Conclusion. Abundant evidence suggests that baclofen may be a useful approach for the treatment of GERD patients; however, a larger well-designed research study would further confirm this recommendation.

Impairment of chemical clearance is relevant to the pathogenesis of refractory reflux oesophagitis

BACKGROUND

The pathophysiological mechanisms underlying proton pump inhibitor-refractory reflux oesophagitis has been scarcely studied.

AIMS

To assess impedance-pH parameters relevant to the pathogenesis of refractory reflux oesophagitis.

METHODS

Cases referred for heartburn/regurgitation refractory to high-dosage proton pump inhibitors between January 2008 and December 2012 were reviewed and subdivided into refractory oesophagitis (29 patients, 72% males, median age 50 years), healed oesophagitis (18 patients, 67% males, median age 54 years), and non-erosive reflux disease (49 patients, 53% males, median age 42 years). On-therapy impedance-pH tracings were blindly re-analysed by one observer to assess gastric and oesophageal acid exposure time and chemical clearance as expressed by the post-reflux swallow-induced peristaltic wave index.

RESULTS

The median gastric and oesophageal acid exposure time did not differ among the three groups (35%, 34%, 41% and 1.2%, 0.7%, 0.8%, respectively; P>0.05 for all comparisons). A normal oesophageal acid exposure time was found in two thirds of patients with refractory oesophagitis. The post-reflux swallow-induced peristaltic wave index was significantly lower in refractory oesophagitis (16%) than in healed oesophagitis (30%) and non-erosive reflux disease (29%) (P=0.003).

CONCLUSIONS

Refractory reflux oesophagitis is characterized by impairment of chemical clearance. Adequate acid suppression is found in the majority of patients who would likely not benefit from further proton pump inhibitor dose escalation.

Gastroesophageal reflux symptoms not responding to proton pump inhibitor: GERD, NERD, NARD, esophageal hypersensitivity or dyspepsia?

Gastroesophageal reflux (GER) is a common gastrointestinal process that can generate symptoms of heartburn and chest pain. Proton pump inhibitors (PPIs) are the gold standard for the treatment of GER; however, a substantial group of GER patients fail to respond to PPIs. In the past, it was believed that acid reflux into the esophagus causes all, or at least the majority, of symptoms attributed to GER, with both erosive esophagitis and nonerosive outcomes. However, with modern testing techniques it has been shown that, in addition to acid reflux, the reflux of nonacid gastric and duodenal contents into the esophagus may also induce GER symptoms. It remains unknown how weakly acidic or alkaline refluxate with a pH similar to a normal diet induces GER symptoms. Esophageal hypersensitivity or functional dyspepsia with superimposed heartburn may be other mechanisms of symptom generation, often completely unrelated to GER. Detailed studies investigating the pathophysiology of esophageal hypersensitivity are not conclusive, and definitions of the various disease states may overlap and are often confusing. The authors aim to clarify the pathophysiology, definition, diagnostic techniques and medical treatment of patients with heartburn symptoms who fail PPI therapy.

On-demand proton pump inhibitory treatment in overweight/obese patients with gastroesophageal reflux disease: are there pharmacodynamic arguments for using higher doses?

BACKGROUND

Increased body mass index (BMI) is associated with a higher risk of gastroesophageal reflux disease (GORD).

AIM

To investigate whether overweight/obesity affects proton pump inhibitor pharmacodynamics when used in a single dose in patients with GORD.

METHODS

Post hoc analyses by patient BMI were performed on data from two single-center, double-blind, single-dose, crossover studies comparing the pharmacodynamics of rabeprazole 20 mg and pantoprazole 40 mg in GORD patients with a history of nocturnal heartburn. The primary endpoint was the mean percentage of time with intragastric pH >4 between lean and overweight/obese patients (BMI <25 and ≥25).

RESULTS

24 h baseline intragastric pH values were not different between BMI groups. The pharmacodynamic effects of both proton pump inhibitors were not significantly different between BMI groups, and no evidence was found for an interaction between BMI and treatment. As compared with pantoprazole, rabeprazole showed a significantly greater effect on the antisecretory response for both BMI groups.

CONCLUSIONS

Overweight/obesity in GORD patients does not appear to affect the antisecretory efficacy of a single dose of rabeprazole and pantoprazole. These data do not support adapting the dosage of rabeprazole and pantoprazole according to BMI in GORD patients when administered as an on-demand therapy schedule.

The effect of laparoscopic sleeve gastrectomy with or without hiatal hernia repair on gastroesophageal reflux disease in obese patients

BACKGROUND

Obesity is an independent risk factor for gastroesophageal reflux disease (GERD), which is often associated with the presence of a hiatal hernia (HH). Despite increasing popularity of laparoscopic sleeve gastrectomy (LSG) in bariatric surgery, its effect on GERD is still unclear. The objective of this study was to evaluate the effect of LSG with or without hiatal hernia repair (HHR) on GERD in obese patients.

METHODS

Seventy-eight patients with HH underwent LSG with concomitant HHR (LSG+HHR group). Their data were compared with that of 102 patients without HH, who underwent only LSG (LSG-group). All patients underwent a standardized questionnaire, a double-contrast barium swallow, and an upper-gastrointestinal endoscopy before the surgical procedure and at least 6 months later.

RESULTS

At baseline, the prevalence of GERD symptoms and their frequency-intensity scores did not differ between groups. At follow up, there was a significant decrease in the prevalence of typical GERD symptoms only in the LSG-group (P = .003). LSG+HHR patients showed a significantly higher heartburn frequency-intensity score compared with LSG patients (P = .009).

CONCLUSION

This finding confirms that LSG has a beneficial effect on relieving GERD symptoms, although the underlying mechanisms are still unclear; conversely, the procedure of HHR did not produce any improvement in GERD symptoms.

Pathophysiology of gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) is one of the most common digestive diseases in the Western world, with typical symptoms, such as heartburn, regurgitation, or retrosternal pain, reported by 15% to 20% of the general population. The pathophysiology of GERD is multifactorial. Our understanding of these factors has significantly improved in recent years, with increased understanding of the acid pocket and hiatal hernia and how these factors interact. Although our insight has significantly increased over the past years, more studies are required to better understand symptom generation in GERD, especially in patients with therapy-resistant symptoms.

Current pharmacological management of gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD), a common disorder with troublesome symptoms caused by reflux of gastric contents into the esophagus, has adverse impact on quality of life. A variety of medications have been used in GERD treatment, and acid suppression therapy is the mainstay of treatment for GERD. Although proton pump inhibitor is the most potent acid suppressant and provides good efficacy in esophagitis healing and symptom relief, about one-third of patients with GERD still have persistent symptoms with poor response to standard dose PPI. Antacids, alginate, histamine type-2 receptor antagonists, and prokinetic agents are usually used as add-on therapy to PPI in clinical practice. Development of novel therapeutic agents has focused on the underlying mechanisms of GERD, such as transient lower esophageal sphincter relaxation, motility disorder, mucosal protection, and esophageal hypersensitivity. Newer formulations of PPI with faster and longer duration of action and potassium-competitive acid blocker, a newer acid suppressant, have also been investigated in clinical trials. In this review, we summarize the current and developing therapeutic agents for GERD treatment.

Esophageal chemical clearance is impaired in gastro-esophageal reflux disease--a 24-h impedance-pH monitoring assessment

BACKGROUND

Impedance-pH monitoring allows assessment of retrograde and antegrade intra-esophageal movement of fluids and gas. Reflux is followed by volume clearance and chemical clearance, elicited by secondary and swallow-induced peristalsis, respectively. We aimed to assess whether chemical clearance is impaired in gastro-esophageal reflux disease (GERD).

METHODS

Blinded retrospective review of impedance-pH tracings from patients with erosive reflux disease (ERD) and non-erosive reflux disease (NERD), and from proton pump inhibitor (PPI)-refractory patients before and after laparoscopic fundoplication. The number of refluxes followed within 30 s by swallow-induced peristaltic waves was divided by the number of total refluxes to obtain a parameter representing chemical clearance namely the postreflux swallow-induced peristaltic wave (PSPW) index.

KEY RESULTS

The PSPW index was significantly lower in 31 ERD (15%) and in 44 NERD (33%) off-PPI patients than in 30 controls (75%), as well as in 18 ERD (16%) and in 48 NERD (31%) on-PPI patients than in 26 on-PPI functional heartburn (FH) cases (67%) (P < 0.05 for all comparisons). In 29 PPI-refractory patients, the median PSPW index was unaltered by otherwise effective antireflux surgery (20% postoperatively, 21% preoperatively). The overall sensitivity, specificity, positive, and negative predictive values of the PSPW index in identifying GERD patients were 97%, 89%, 96%, and 93%.

CONCLUSIONS & INFERENCES

Impairment of chemical clearance is a primary pathophysiological mechanism specific to GERD: it is unaffected by medical/surgical therapy, is not found in FH, and is more pronounced in ERD than in NERD. Using the PSPW index could improve the diagnostic efficacy of impedance-pH monitoring.

WHAT IS THE REAL IMPAIRMENT ON ESOPHAGEAL MOTILITY IN PATIENTS WITH GASTROESOPHAGEAL REFLUX DISEASE?

Context Impairment of esophageal motility is a common finding in patients with gastroesophageal reflux disease (GERD) as reduced lower esophageal sphincter (LES) basal pressure. A very low LES pressure might facilitate the occurrence of more gastroesophageal reflux whereas abnormal esophageal peristalsis may contribute to impaired esophageal clearance after reflux. Objective Evaluate the esophageal motor function of the lower esophageal sphincter and esophageal body in the various forms of gastroesophageal reflux disease. Methods The manometrics records of 268 patients, who had evaluation of the esophageal motility as part of the diagnostic gastroesophageal reflux disease were split into four groups, as follows: 33 patients who had no esophagitis; 92 patients who had erosive esophagitis; 101 patients who had short Barrett's esophagus and 42 patients who had long Barrett's esophagus. Results The group who had long Barrett's esophagus showed smaller mean LES pressure and higher percentage of marked LES hypotonia; in the distal segment of the esophageal body the this group showed higher percentage of marked hypocontractility of the distal segment (<30 mm Hg); this same group showed higher percentage of esophageal motility disorders. Conclusions The most intense esophageal motility disorders and lower pressure of lower esophageal sphincter were noted in the group with long Barrett's esophagus. Those with reflux esophagitis and short Barrett's esophagus had esophageal motility impairment, intermediate among patients with esophagitis and long Barrett's esophagus. Patients with typical symptoms of gastroesophageal reflux but without esophagitis by endoscopy study showed no impairment of esophageal motility.

The effect of rabeprazole on LES tone in experimental rat model

INTRODUCTION

Despite adequate treatment with proton pump inhibitors (PPIs), symptoms of gastroesophageal reflux disease (GERD) may remain persistent as well as Barrett's esophagus may emerge. It may be proposed that the relaxant effect of PPIs on the smooth muscles may lead to resistance of symptoms. The aim of this study is to investigate effects of rabeprazole on the lower esophageal sphincter (LES) pressure with a rat model.

MATERIALS AND METHODS

Sixteen rats were grouped as control and treatment groups. After obtaining LES tissues followed by a 60 min equilibration period for stabilization, contractile response to carbachol was obtained by application of single dose of carbachol to have a final concentration of 10(-6) M in the organ bath. After the contractions reached a plateau, concentration-response relationships for rabeprazole were obtained in a cumulative manner in the treatment group.

RESULTS

In the carbachol contracted LES preparations; 1.5 × 10(-6) and 1.5×10(-5) M of rabeprazole caused 6.08% and 11.34% relaxations respectively which were not statistically significant. However, mean integral relaxation value for 4.5 × 10(-5) M of rabeprazole was 17.34% and this relaxation was significant compared with controls.

CONCLUSIONS

In the present study, rabeprazole caused no direct significant change in LES tone in the therapeutic dose range applied to the organ bath. However, rabeprazole at the high dose caused a significant decrease in the LES tone.

Effect of lateral positioning on gastroesophageal reflux (GER) and underlying mechanisms in GER disease (GERD) patients and healthy controls

BACKGROUND

Posture has been shown to influence the number of transient lower esophageal sphincter relaxation (TLESRs) and gastroesophageal reflux (GER), however, the physiology explaining the influence of right lateral position (RLP), and left lateral position (LLP) is not clear. The aim of this study was to determine the influence of RLP and LLP on TLESRs and GERD after a meal in GER disease (GERD) patients and healthy controls (HC) while monitoring gastric distension and emptying.

METHODS

Ten GERD patients and 10 HC were studied for 90 min (30 min test meal infusion, 30 min postprandial in either RLP or LLP (randomly assigned) and 30 min in alternate position). The study was repeated on a separate day in reverse position order. TLESRs, GER, and gastric emptying rate were recorded using manometry, multichannel intraluminal impedance, and (13) C-octanoate breath tests. Gastric distension was visualized by five serial gastric volume scintigraphy scans during the first 30 min.

KEY RESULTS

Gastroesophageal reflux, (GER) disease patients had increased numbers of TLESRs in RLP compared to LLP in the first postprandial hour [5 (4-14) and 4.5 (2-6), respectively, P = 0.046] whereas the number of TLESRs was not different in RLP and LLP [4 (2-4) and 4 (3-6), respectively, P = 0.7] in HC. Numbers of GER increased similar to TLESRs in GERD patients. In GERD patients, gastric emptying reached peak (13)CO(2) excretion faster and proximal gastric distension was more pronounced.

CONCLUSIONS & INFERENCES

In GERD patients, TLESRs, GER, distension of proximal stomach, and gastric emptying are increased in RLP compared to LLP. This effect is not seen in HC.

Impaired ghrelin signaling is associated with gastrointestinal dysmotility in rats with gastroesophageal reflux disease

Gastroesophageal reflux disease (GERD) is often associated with decreased upper gastrointestinal motility, and ghrelin is an appetite-stimulating hormone known to increase gastrointestinal motility. We investigated whether ghrelin signaling is impaired in rats with GERD and studied its involvement in upper gastrointestinal motility. GERD was induced surgically in Wistar rats. Rats were injected intravenously with ghrelin (3 nmol/rat), after which gastric emptying, food intake, gastroduodenal motility, and growth hormone (GH) release were investigated. Furthermore, plasma ghrelin levels and the expression of ghrelin-related genes in the stomach and hypothalamus were examined. In addition, we administered ghrelin to GERD rats treated with rikkunshito, a Kampo medicine, and examined its effects on gastroduodenal motility. GERD rats showed a considerable decrease in gastric emptying, food intake, and antral motility. Ghrelin administration significantly increased gastric emptying, food intake, and antral and duodenal motility in sham-operated rats, but not in GERD rats. The effect of ghrelin on GH release was also attenuated in GERD rats, which had significantly increased plasma ghrelin levels and expression of orexigenic neuropeptide Y/agouti-related peptide mRNA in the hypothalamus. The number of ghrelin-positive cells in the gastric body decreased in GERD rats, but the expression of gastric preproghrelin and GH secretagogue receptor mRNA was not affected. However, when ghrelin was exogenously administered to GERD rats treated with rikkunshito, a significant increase in antral motility was observed. These results suggest that gastrointestinal dysmotility is associated with impaired ghrelin signaling in GERD rats and that rikkunshito restores gastrointestinal motility by improving the ghrelin response.

Gastroesophageal reflux disease and airway hyperresponsiveness: concomitance beyond the realm of chance?

Gastroesophageal reflux disease and asthma are both quite common the world over, and they can coexist. However, the nature of the relationship between these two diseases remains unclear. In this study, we review controversial aspects of the relationships among asthma, airway hyperresponsiveness, and gastroesophageal reflux disease in adults and in children.

In gastroesophageal reflux disease, differential gene expression in the duodenum points towards enhanced chylomicron production and secretion

BACKGROUND

Duodenal signaling affects esophageal motility and perception, both pathophysiological factors in gastroesophageal reflux disease (GERD). Duodenal gene expression abnormalities, contributing to altered esophageal sensorimotor function, have not been reported to date.

AIM

To identify differentially expressed genes in GERD patients' duodenum.

METHODS

Twenty GERD patients (total 24-h acid exposure 6-12%, SAP ≥95%) and ten healthy controls (HC) were included. Two weeks prior to duodenal biopsy collection, ten patients discontinued proton pump inhibitor (PPI) treatment and ten took maximum dose PPI. RNA was profiled on an Affymetrix Human Genome U133 Plus 2.0 array (Affymetrix, Santa Clara, CA, USA). Genes exhibiting a fold change ≥ 1.4 (t test p value <1E-4) were considered differentially expressed. A subset of 21 differentially expressed genes was selected for confirmatory TaqMan low-density array RT-PCR. Mucosal apolipoprotein A-IV (apoA-IV) and cholecystokinin (CCK) concentrations were determined by ELISA and RIA, respectively.

RESULTS

In GERD patients off PPI, 23 up- and 23 down-regulated genes relative to HC were found. In GERD patients on PPI, 33 and five genes were higher, respectively, lower expressed. The majority of up-regulated genes were associated with lipid absorption, particularly triglyceride resynthesis and intracellular vesicular transport, rate-limiting processes for chylomicron production and secretion. Differential expression of 11 genes was confirmed by RT-PCR. Mucosal apoA-IV and CCK concentrations (signaling proteins released upon chylomicron secretion) were similar in GERD patients and HC.

CONCLUSIONS

The identified mRNA expression differences suggest that in GERD patients' duodenum, the chylomicron production and secretion potential is elevated, and may underlie a mechanism by which postprandial duodenal signaling contributes to GERD symptom generation.

Gastro-oesophageal reflux disease is associated with up-regulation of desmosomal components in oesophageal mucosa

AIMS

Gastro-oesophageal reflux disease (GERD) is associated with impaired epithelial barrier function. This study was aimed at investigating the role of desmosomal proteins in relation to GERD.

METHODS AND RESULTS

Ninety-five patients with GERD-related symptoms (erosive, n = 51; non-erosive, n = 44) and 27 patients lacking those symptoms were included. Endoscopic and histological characterization of oesophagitis was performed according to the Los Angeles and Ismeil-Beigi criteria, respectively. Multiple biopsies were taken from the oesophageal mucosa of each patient. Gene expression analysis of plakoglobin, desmoglein-1, desmoglein-2 and desmoglein-3 was performed by quantitative real time (RT)-polymerase chain reaction and immunohistochemistry in the oesophageal mucosa. Routine histology revealed specific GERD-related alterations, such as dilatation of intercellular spaces (DIS), basal cell hyperplasia (BCH), and elongation of the papillae, in the oesophageal mucosa of patients with GERD, as compared with controls (all parameters: P < 0.05). All four genes and corresponding proteins were found to be up-regulated by between 1.7 and 8.1-fold (transcript level, P < 0.05; protein level, P < 0.05). Induced gene expression levels of plakoglobin, desmoglein-1 and desmoglein-2 correlated significantly with DIS and BCH.

CONCLUSIONS

Taken together, the uniform up-regulation of desmosomal genes/proteins in the oesophageal mucosa of patients with GERD supports the concept of architectural and molecular changes in the desmosomal compartment in the pathogenesis of GERD.

[N-methyl-11C]cholylsarcosine, a novel bile acid tracer for PET/CT of hepatic excretory function: radiosynthesis and proof-of-concept studies in pigs

Excretion of conjugated bile acids into bile is an essential function of the liver, and impairment of canalicular bile acid secretion leads to cholestatic liver injury. However, hepatic excretory function cannot be quantified in vivo because of the lack of suitable methods. Cholylsarcosine is an analog of the endogenous bile acid conjugate cholylglycine and exhibits characteristics in vivo that led us to hypothesize that the (11)C-labeled form, that is, [N-methyl-(11)C]cholylsarcosine ((11)C-cholylsarcosine), would be a suitable PET tracer for quantification of hepatic excretory function.

METHODS

A method for radiosynthesis of (11)C-cholylsarcosine was developed involving (11)C-methylation of glycine followed by conjugation with cholic acid. Blood-to-liver uptake and liver-to-bile excretion were investigated in vivo by dynamic (11)C-cholylsarcosine PET/CT of 2 anesthetized pigs. In pig 1, a second dynamic (11)C-cholylsarcosine PET/CT examination was preceded by a high dose of the endogenous bile acid conjugate cholyltaurine to investigate possible inhibition of the transhepatocellular transport of (11)C-cholylsarcosine. In pig 2, a second (11)C-cholylsarcosine administration was given to determine the biodistribution of the tracer by means of 5 successive whole-body PET/CT recordings. Possible formation of (11)C-metabolites was investigated by analysis of blood and bile samples from a third pig.

RESULTS

The radiochemical yield was 13% ± 3% (n = 7, decay-corrected) and up to 1.1 GBq of (11)C-cholylsarcosine was produced with a radiochemical purity greater than 99%. PET/CT studies showed rapid blood-to-liver uptake and liver-to-bile excretion of (11)C-cholylsarcosine, with radioactivity concentrations being more than 90 times higher in the bile ducts than in liver tissue. Cholyltaurine inhibited the transhepatocellular transport of (11)C-cholylsarcosine, indicating that the tracer is transported by one or more of the same hepatic transporters as cholyltaurine. (11)C-cholylsarcosine underwent an enterohepatic circulation and reappeared in liver tissue and bile ducts after approximately 70 min. There were no detectable (11)C-metabolites in the plasma or bile samples, indicating that the novel conjugated bile acid (11)C-cholylsarcosine was not metabolized in the liver or in the intestines. The effective absorbed dose of (11)C-cholylsarcosine was 4.4 μSv/MBq.

CONCLUSION

We have synthesized a novel conjugated bile acid analog, (11)C-cholylsarcosine, and PET/CT studies on anesthetized pigs showed that the hepatic handling of tracer uptake from blood and excretion into the bile was comparable to that for the endogenous bile acid cholyltaurine. This tracer may be valuable for future studies of normal and pathologic hepatic excretory functions in humans.

Mechanisms of reflux perception in gastroesophageal reflux disease: a review

Patients with reflux symptoms often do not have excessive esophageal acid exposure, and patients with severe gastroesophageal reflux often do not have reflux symptoms. Understanding why different types of reflux induce symptoms in different patients is vital for addressing therapeutic gaps in the treatment of gastroesophageal reflux disease (GERD). Here we review studies providing insight into how gastroesophageal reflux is perceived, with a focus on comparing reflux characteristics and esophageal sensitivity among subgroups of patients with GERD. The available studies indicate that patients with nonerosive reflux disease have fewer acid reflux episodes and thus less esophageal acid exposure than patients with reflux esophagitis but perceive less intense stimuli because of greater esophageal sensitivity. Reflux characteristics other than acidity, such as the presence of bile, pepsin, liquid, or gas in reflux, and the proximal extent or volume of reflux, may also contribute to symptom perception. Factors contributing to greater esophageal sensitivity may include impaired mucosal barrier function, peripherally mediated esophageal sensitivity (enhanced esophageal receptor signaling), and centrally mediated esophageal sensitivity (physiological stressors, sensitization of spinal sensory neurons). Further insight into mechanisms of reflux perception may require a shift toward studies aimed at understanding predisposing cellular, molecular, and genetic factors.

Proton pump inhibitors omeprazole, lansoprazole and pantoprazole induce relaxation in the rat lower oesophageal sphincter

Objectives

We aimed to investigate effects of the proton pump inhibitors (PPIs) omeprazole, lansoprazole and pantoprazole, which are currently used for the treatment of hyperacidity and gastro-oesophageal reflux, on the reactivity of the isolated rat lower oesophageal sphincter.

Methods

Omeprazole, lansoprazole and pantoprazole (all 10–9–10–3m, cumulatively) were tested on carbachol-induced (10–6m) contraction. In addition, the effects of PPI preincubation (all 10–3m) on the contractions induced by cumulative carbachol (10−9–10−5m), angiotensin-2 (10−9–10–5m) or electrical field stimulation (EFS; 40 V, 32 Hz, 1 ms, 10 s) were assessed. Finally, the effects of PPI on the spontaneous contractile activity of the tissue were also evaluated.

Key findings

PPI relaxed precontracted lower oesophageal sphincter in a concentration-dependent manner and suppressed carbachol-, angiotensin- and EFS-induced contractions. Furthermore, PPI attenuated spontaneous contractile activity of the tissue.

Conclusions

Omeprazole, lansoprazole and pantoprazole had a suppressor effect on lower oesophageal sphincter contractions.

Genetic factors in the pathogenesis of gastroesophageal reflux disease

Multiple factors play a role in the pathogenesis of gastroesophageal reflux disease (GERD). Two landmark studies showing higher concordance of disease in monozygotic than dizygotic twin pairs suggested the role of host genetic factors in its pathogenesis. Recent studies have shown that genetic polymorphism in genes influencing host's inflammatory response, drug metabolism, cell cycle regulation, xenobiotic pathways, DNA repair, mutagenesis, esophageal sensory function and gene silencing are associated with risk of GERD and its sequelae-Barrett's esophagus and esophageal adenocarcinoma. However, more studies on larger sample size are needed before reaching a definite conclusion on the role of an individual gene.