Pathophysiology of gastro-esophageal reflux disease: a role for mucosa integrity?

Dysphagia-related mucositis in children undergoing chemotherapy: The COMEDY pattern

OBJECTIVES

Children undergoing chemotherapy can experience dysphagia due to non-erosive reflux disease (NERD). Oral mucositis (OM) associated with NERD-dysphagia in children with cancer has recently been defined with the acronym COMEDY (Clenching, Oral Mucositis, closed Eyes, DYsphagia). This study aims to identify the prevalence of the COMEDY pattern among chemotherapy-induced OM.

SUBJECTS AND METHODS

Forty-two medical records of children undergoing chemotherapy for haemato-oncologic diseases and presenting OM were reviewed. The following data were collected: age, type of haemato-oncologic disease, presence of dysphagia, type of oral mucosal lesions (i.e. traditional oral mucositis or COMEDY pattern), site of oral lesions, ear-nose-throat (ENT) assessment for the indirect signs of NERD and paediatric neuro-psychiatric (PNP) assessment.

RESULTS

Among 42 children with chemotherapy-related OM, 6 patients (14.2%) showed the COMEDY pattern. Besides the characteristic clinical aspect of the oral mucosa, initially classified as grade II OM, these children suffered from NERD-related dysphagia and PNP issues.

CONCLUSION

A COMEDY pattern can occur in a number of cases of chemotherapy-induced OM; recognizing this pattern may improve the effectiveness of treatment.

Inflammatory and Proliferative Pathway Activation in Human Esophageal Myofibroblasts Treated with Acidic Bile Salts

Subepithelial human esophageal myofibroblasts (HEMFs) in gastroesophageal reflux disease (GERD) are exposed to luminal contents via impaired squamous epithelium barrier integrity. The supernatant of HEMFs treated with acidic bile salts reflective of in vivo reflux increases squamous epithelial thickness. We aimed to identify the involved mechanisms using an unbiased approach. Acidic-bile-salt-treated primary HEMF cultures (n = 4) were submitted for RNA-Seq and analyzed with Partek Flow followed by Ingenuity Pathway Analysis (IPA). A total of 1165 molecules (579 downregulated, 586 upregulated) were differentially expressed, with most top regulated molecules either extracellular or in the plasma membrane. Increases in HEMF CXCL-8, IL-6, AREG, and EREG mRNA, and protein secretion were confirmed. Top identified canonical pathways were agranulocyte and granulocyte adhesion and diapedesis, PI3K/AKT signaling, CCR5 signaling in macrophages, and the STAT3 pathway. Top diseases and biological functions were cellular growth and development, hematopoiesis, immune cell trafficking, and cell-mediated response. The targets of the top upstream regulator ErbB2 included CXCL-8, IL-6, and AREG and the inhibition of CXCL-8 in the HEMF supernatant decreased squamous epithelial proliferation. Our work shows an inflammatory/immune cell and proliferative pathways activation in HEMFs in the GERD environment and identifies CXCL-8 as a HEMF-derived chemokine with paracrine proliferative effects on squamous epithelium.

Pharmacologic treatment of GERD in adolescents: Is esophageal mucosal protection an option?

Background

Gastroesophageal reflux disease (GERD) is still a challenging and difficult to treat condition in children. Although acid suppression represents the mainstay of treatment in adolescents, it is not devoid of adverse events, especially in the long-term.

Objectives

In this investigation we explored a new therapeutic avenue in GERD, that is esophageal mucosal protection.

Design

To this end, we performed an investigator-initiated, retrospective study to evaluate the efficacy and safety of a short-term treatment with Esoxx™ medical device in 25 adolescents with GERD-related symptoms. This mucoadhesive formulation contains two natural mucopolysaccharides (sodium hyaluronate and chondroitin sulphate) and adheres to the esophageal mucosa, exerting a protective effect against refluxed gastric contents and allowing mucosal healing.

Methods

Heartburn, epigastric burning and post-prandial regurgitation were scored with a pain VAS scale and re-evaluated after 3-week treatment with Esoxx (one stick post-prandially, three times daily).

Results

All patients completed the treatment without adverse effects and with good tolerability and compliance. All the three major symptoms significantly (p<0.001) improved after treatment. No patient required additional investigation (i.e. upper Gastrointestinal endoscopy) or medication (i.e. antisecretory drugs).

Conclusion

The results of this pilot study suggest that esophageal mucosal protection is a promising therapeutic avenue for GERD also in children. Provided, these data be confirmed by a large, randomized clinical trial, this medical device can enter our therapeutic armamentarium against this challenging disease.

Kyoto international consensus report on anatomy, pathophysiology and clinical significance of the gastro-oesophageal junction

OBJECTIVE

An international meeting was organised to develop consensus on (1) the landmarks to define the gastro-oesophageal junction (GOJ), (2) the occurrence and pathophysiological significance of the cardiac gland, (3) the definition of the gastro-oesophageal junctional zone (GOJZ) and (4) the causes of inflammation, metaplasia and neoplasia occurring in the GOJZ.

DESIGN

Clinical questions relevant to the afore-mentioned major issues were drafted for which expert panels formulated relevant statements and textural explanations.A Delphi method using an anonymous system was employed to develop the consensus, the level of which was predefined as ≥80% of agreement. Two rounds of voting and amendments were completed before the meeting at which clinical questions and consensus were finalised.

RESULTS

Twenty eight clinical questions and statements were finalised after extensive amendments. Critical consensus was achieved: (1) definition for the GOJ, (2) definition of the GOJZ spanning 1 cm proximal and distal to the GOJ as defined by the end of palisade vessels was accepted based on the anatomical distribution of cardiac type gland, (3) chemical and bacterial (Helicobacter pylori) factors as the primary causes of inflammation, metaplasia and neoplasia occurring in the GOJZ, (4) a new definition of Barrett's oesophagus (BO).

CONCLUSIONS

This international consensus on the new definitions of BO, GOJ and the GOJZ will be instrumental in future studies aiming to resolve many issues on this important anatomic area and hopefully will lead to better classification and management of the diseases surrounding the GOJ.

Determinants of reflux perception in patients with non-erosive reflux disease who have reflux-related symptoms on potassium-competitive acid blocker therapy

BACKGROUND

This study investigated potential determinants of reflux perception in patients with non-erosive reflux disease (NERD) who had reflux-related symptoms on potassium-competitive acid blocker (P-CAB) therapy.

METHODS

This study included 23 patients with reflux-related symptoms despite P-CAB therapy. Esophageal impedance-pH monitoring was performed on P-CAB and the following potential determinants of reflux perception were investigated: reflux nadir pH value; change in pH (baseline-nadir); bolus clearance time; reflux extent; proportions of acid, weakly acidic, and weakly alkaline reflux episodes; and proportions of liquid and mixed reflux episodes.

RESULTS

Overall, ≥ 90% of all and symptomatic reflux episodes were weakly acidic reflux and 63% of symptomatic reflux episodes were reflux episodes with pH ≥ 5. There were no significant differences regarding potential determinants between symptomatic and asymptomatic reflux episodes. However, the proportion of symptomatic reflux episodes was significantly greater with pH < 5 (13.8%) than with pH ≥ 5 (9.5%) (P = 0.0431). In reflux episodes with pH < 5, the proportion of symptomatic reflux episodes was significantly greater in proximal sites (20.6%) than in distal sites (10.6%) (P = 0.0178). Conversely, in reflux episodes with pH ≥ 5, there was no significant difference regarding reflux perception according to reflux extent (proximal: 9.6% vs. distal: 9.0%, P = 0.9337).

CONCLUSIONS

In patients with P-CAB-resistant NERD, reflux symptoms were mainly caused by reflux episodes with pH ≥ 5 on P-CAB therapy. The proportions of symptomatic reflux episodes among reflux sites differed according to reflux pH value; thus, the mechanisms of reflux perception may differ according to reflux pH value.

Current Advancement on the Dynamic Mechanism of Gastroesophageal Reflux Disease

Gastroesophageal reflux disease (GERD) is a common clinical disease associated with upper gastrointestinal motility disorders. Recently, with improvements in living standards and changes in lifestyle and dietary habits, the incidence of GERD has been increasing yearly. However, the mechanism of GERD has not been fully elucidated due to its complex pathogenesis, and this had led to unsatisfactory therapeutic outcomes. Currently, the occurrence and development of GERD involve multiple factors. Its pathogenesis is mainly thought to be related to factors, such as lower esophageal sphincter pressure, transient lower esophageal sphincter relaxation, crural diaphragmatic dysfunction, hiatus hernia, and impaired esophageal clearance. Therefore, explaining the pathogenesis of GERD more clearly and systematically, exploring potential and effective therapeutic targets, and choosing the best treatment methods have gradually become the focus of scholars' attention. Herein, we reviewed current advancements in the dynamic mechanism of GERD to better counsel patients on possible treatment options.

Amelioration of alcohol‑induced gastric mucosa damage by oral administration of food‑polydeoxyribonucleotides

Gastritis refers to inflammation caused by injury to the gastric epithelium, which is usually due to excessive alcohol consumption and prolonged use of nonsteroidal anti-inflammatory drugs. Millions of individuals worldwide suffer from this disease. However, the lack of safe and promising treatments makes it urgent to explore and develop leads from natural resources. Therefore, food as medicine may be the best approach for the treatment of these disorders. The present study described the protective effects of food-polydeoxyribonucleotides (f-PDRNs) in a rat model of gastric mucosal injury induced by HCl-EtOH. Administration of f-PDRN was performed with low-PRF002 (26 mg/kg/day), medium-PRF002 (52 mg/kg/day) and high-PRF002 (78 mg/kg/day) on the day of autopsy. The site of damage to the mucous membrane was also analysed. In addition, an increase in gastric juice pH, total acidity of gastric juice and decrease in gastric juice secretion were confirmed, and gastric juice secretion-related factors corresponding to the administration of f-PDRN were analysed. Administration of f-PDRN reduced the mRNA expression of histamine H2 receptor, muscarinic acetylcholine receptor M3, cholecystokinin 2 receptor and H⁺/K⁺ ATPase related to gastric acid secretion and downregulation of histamine, myeloperoxidase and cyclic adenosine monophosphate. In addition, it was histologically confirmed that the loss of epithelial cells and the distortion of the mucosa were recovered in the group in which f-PDRN was administered compared to the model group with gastric mucosa damage. In summary, the present study suggested that f-PDRN has therapeutic potential and may have beneficial effects if taken regularly as a food supplement.

Does Trypsin Oral Spray (Viruprotect®/ColdZyme®) Protect against COVID-19 and Common Colds or Induce Mutation? Caveats in Medical Device Regulations in the European Union

BACKGROUND

nasal or oral sprays are often marketed as medical devices (MDs) in the European Union to prevent common cold (CC), with ColdZyme^®/Viruprotect^® (trypsin/glycerol) mouth spray claiming to prevent colds and the COVID-19 virus from infecting host cells and to shorten/reduce CC symptoms as an example. We analyzed the published (pre)-clinical evidence.

METHODS

preclinical: comparison of in vitro tests with validated host cell models to determine viral infectivity. Clinical: efficacy, proportion of users protected against virus (compared with non-users) and safety associated with trypsin/glycerol.

RESULTS

preclinical data showed that exogenous trypsin enhances SARS-CoV-2 infectivity and syncytia formation in host models, while culture passages in trypsin presence induce spike protein mutants. The manufacturer claims >98% SARS-CoV-2 deactivation, although clinically irrelevant as based on a tryptic viral digest, inserting trypsin inactivation before host cells exposure. Efficacy and safety were not adequately addressed in clinical studies or leaflets (no COVID-19 data). Protection was obtained among 9-39% of users, comparable to or lower than placebo-treated or non-users. Several potential safety risks (tissue digestion, bronchoconstriction) were identified.

CONCLUSIONS

the current European MD regulations may result in insufficient exploration of (pre)clinical proof of action. Exogenous trypsin exposure even raises concerns (higher SARS-CoV-2 infectivity, mutations), whereas its clinical protective performance against respiratory viruses as published remains poor and substandard.

Pharmacological Management of Gastro-Esophageal Reflux Disease: An Update of the State-of-the-Art

Gastro-esophageal reflux disease (GERD) is a highly prevalent, chronic disorder, whose knowledge remains limited and the management of these patients changes continuously. This review provides a summary of the most recent advancements in the pathogenesis of this disease and the new drugs introduced into the market to overcome some of the unmet needs of traditional therapies. Nowadays, the most fruitful diagnostic examinations are 24-hour impedance-pH monitoring, which allows us to separate true NERD from esophageal functional disorders and high-resolution manometry, which helps to exclude the existence of motility disorders sharing the same symptoms of GERD. Proton pump inhibitors (PPIs) remain the first-choice therapy in the treatment of GERD, but a consistent proportion of these patients continue to experience symptoms despite their intake. These cases pertain mainly to the subpopulation with non-erosive reflux disease (NERD) and represent very challenging clinical situations, because it is mandatory to understand the reasons for PPI failure. The management of these difficult patients requires necessarily to test them and avoid the use of empiric treatments that are often unsuccessful, costly and potentially dangerous. Recently, several new drugs have been used to increase the defensive properties of this mucosa with promising results in randomized clinical trials.

Bile Acids as a New Type of Steroid Hormones Regulating Nonspecific Energy Expenditure of the Body (Review)

The review is devoted to the systematization, classification, and generalization of the results of modern scientific research on the role of bile acids as a new class of steroid hormones. The paper presents the evidence for bile acid participation in the regulation of the body energy metabolism, body weight control, as well as the pathogenesis of obesity, diabetes mellitus, insulin resistance, and cardiovascular diseases. Particular attention is paid to the role of bile acids in the control of nonspecific energy expenditure of the body. The applied aspects of using the novel data about the membrane and intracellular receptors responsible for the development of hormonal regulatory effects of bile acids are analyzed. According to the authors, the modern data on the role of bile acids in the regulation of body functions allow a deeper understanding of the pathogenesis of body weight disorders and associated cardiovascular diseases. The review demonstrates promising directions in the search for specific methods of prevention and correction of these pathological conditions.

Pharmacologic treatment of GERD: Where we are now, and where are we going?

The introduction of acid inhibition in clinical practice has revolutionized the management of acid-related diseases, leading to the virtual abolition of elective surgery for ulcer disease and relegating antireflux surgery to patients with gastroesophageal reflux disease (GERD) not adequately managed by medical therapy. Proton pump inhibitors (PPIs) are the antisecretory drugs of choice for the treatment of reflux disease. However, these drugs still leave some unmet clinical needs in GERD. PPI-refractoriness is common, and persistent symptoms are observed in up to 40-55% of daily PPI users. Potassium-competitive acid blockers (P-CABs) clearly overcome many of the drawbacks and limitations of PPIs, achieving rapid, potent, and prolonged acid suppression, offering the opportunity to address many of the unmet needs. In recent years, it has been increasingly recognized that impaired mucosal integrity is involved in the pathogenesis of GERD. As a consequence, esophageal mucosal protection has emerged as a new, promising therapeutic avenue. When P-CABS are used as add-on medications to standard treatment, a growing body of evidence suggests a significant additional benefit, especially in the relief of symptoms not responding to PPI therapy. On the contrary, reflux inhibitors are considered a promise unfulfilled, and prokinetic agents should only be used on a case-by-case basis.

Rebamipide using in gastroesophageal reflux disease treatment

Rebamipide is a mucoprotective drug which was developed in Japan in 1990. The therapeutic effect of rebamipide based on the induction of cyclooxygenase-2 and increasing level of prostaglandins, inhibition of oxygen free radicals production, epidermal growth factor stimulation, vascular endothelial growth factor, nitric oxide, and decreasing of lipid peroxidation and neutrophils migration. The combination of proton pump inhibitors and rebamipide is more effective in relieving of gastroesophageal reflux disease symptoms and reducing recurrence rate of disease. Using rebamipide in the treatment of gastroesophageal reflux disease is justified because this drug has a unique mechanism of action, which eliminating the main stages of pathogenesis of the disease.

Relationship between gastroesophageal reflux disease and Helicobacter pylori infection

In recent years, the infection rate of Helicobacter pylori (H. pylori) in China has declined. Due to the relatively large population, the number of H. pylori infection patients in China is still large. For many diseases combined with H. pylori infection, eradication therapy is essential, but the effect of H. pylori on gastroesophageal reflux disease (GERD) is controversial. Therefore, whether to conduct eradication therapy in patients with H. pylori infection remains to be discussed. The pathogenesis of the GERD is related to various factors. This article aims to provide some clues for treating GERD by reviewing the relationship between GERD and H. pylori infection.

Long-Chain Fatty Acid Receptors Mediate Relaxation of the Porcine Lower Esophageal Sphincter

Long-chain fatty acids activate the free fatty acid receptor 1 (FFA1) and FFA4. In the gastrointestinal system, FFA1 and FFA4 have been found in the pancreas and intestine. Fatty food and decreased lower esophageal sphincter (LES) motility are associated with gastroesophageal reflux disease. The effect of long-chain fatty acids on the esophageal motility is unknown. The purpose of this study is to investigate the effects of long-chain fatty acids on the porcine LES motility ex vivo using isometric transducers. In endothelin 1-precontracted porcine LES strips, the FFA1 selective agonists, fasiglifam, TUG424, and GW9508, caused marked relaxations in a concentration-dependent manner. The relative efficacies to elicit relaxation were GW9508 > TUG424 > fasiglifam in both clasp and sling strips. In contrast, the FFA4 specific agonists, TUG891 and GSK137647, produced mild relaxations. In addition, the endogenous FFA1 agonist DHA caused a mild relaxation whereas GW1100, an FFA1 antagonist, inhibited GW9508 induced relaxation of the porcine LES clasp and sling muscle. Both real-time PCR and immunohistochemistry revealed that FFA1 and FFA4 were expressed in the porcine LES. Real-time PCR analysis showed that the FFA4 expression was much lower than FFA1. Taken together, long-chain fatty acid receptor agonists elicit relaxation of the porcine LES. FFA1 might influence LES motility.

2007-2019: a "Third"-Space Odyssey in the Endoscopic Management of Gastrointestinal Tract Diseases

PURPOSE OF REVIEW

The main scope of this review article is to introduce readers to the innovative field of third-space endoscopy and offer a closer look at its history, milestones, and procedure spectrum while discussing ongoing and future challenges arising from its increasing adoption worldwide.

RECENT FINDINGS

Over the past few years, third-space endoscopy has been utilized in various diagnostic and interventional procedures performed throughout the gastrointestinal tract: obliteration of Zenker's diverticulum, myotomy for achalasia, gastroparesis or Hirschsprung's disease, biopsy or removal of subepithelial tumors, stricture management, post-per-oral endoscopic myotomy endoscopic fundoplication, and mediastino-, thoraco-, and peritoneoscopy. Third-space endoscopic interventions have revolutionized the management of esophageal motility disorders, gastroparesis, and gastrointestinal tract subepithelial tumors. Despite the high efficacy and safety of such interventions, some common (e.g., the high level of necessary endoscopic skill) and unique for each procedure (e.g., post-procedure gastroesophageal reflux or poor outcomes in patient subgroups) challenges still remain. Through a dedicated endoscopic training, a rigorous pre-procedure patient evaluation and selection, and the application of modified or new techniques, challenges can be overcome thus establishing existing procedures and paving the way for additional breakthroughs in the field of third-space endoscopy.

An improved surgical procedure to establish a gastroesophageal reflux model with a high incidence of Barrett's esophagus in rats

Barrett's esophagus (BE) is a complication of gastroesophageal reflux disease and is a precursor lesion of esophageal adenocarcinoma. In existing BE models, the incidence of BE is typically low and induction is usually time consuming. In the present study, a gastroesophageal reflux model with a high incidence of BE in rats. Rats were divided into a model group and a sham operation group, and anesthetized with an inhalation anesthesia machine. Stomach-jejunal anastomosis (SJA) and esophagus-jejunal anastomosis (EJA) were simultaneously performed in the model group. The distance between the Treitz ligament and the gastro-jejunal anastomosis was shortened to 3 cm. The distance between the SJA and the EJA was prolonged to 1–1.5 cm. However, 15/40 rats in the model group succumbed to post-surgical complications (mortality rate was 37.5%). The weight of surviving rats in the model group was significantly lower compared with the sham group rats post-surgery. Erosions and ulcers were common of the surviving rats in the model group, with an incidence of 80% (20/25). Squamous cell dysplasia was identified in 40% (10/25) of rats in model group. The modified model was well established within 16 weeks. Notably, the modified surgical procedure used enhanced the incidence of BE in rats from 47% in the EJGJ model (as establish by Zhang) to 100%. To conclude, this model can be used as a reliable animal model for basic research on BE.

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.

An objective in vivo diagnostic method for inflammatory bowel disease

Inflammatory damage to the bowel, as occurs in inflammatory bowel disease (IBD), is debilitating to patients. In both patients and animal experimental models, histological analyses of biopsies and endoscopic examinations are used to evaluate the disease state. However, such measurements often have delays and are invasive, while endoscopy is not quantitatively objective. Therefore, a real-time quantitative method to assess compromised mucosal barrier function is advantageous. We investigated the correlation of in vivo changes in electrical transmural impedance with histological measures of inflammation. Four platinum (Pt) ball electrodes were placed in the lumen of the rat small intestine, with a return electrode under the skin. Electrodes placed within the non-inflamed intestine generated stable impedances during the 3 h testing period. Following an intraluminal injection of 2,4,6-trinitrobenzene sulfonic acid (TNBS), an established animal model of IBD, impedances in the inflamed region significantly decreased relative to a region not exposed to TNBS (p < 0.05). Changes in intestinal transmural impedance were correlated (p < 0.05) with histologically assessed damage to the mucosa and increases in neutrophil, eosinophil and T-cell populations at 3 h compared with tissue from control regions. This quantitative, real-time assay may have application in the diagnosis and clinical management of IBD.

Study on the Therapeutic Effects of Drug and Cognitive-Behavioral Therapy on Non-Erosive Reflux Disease Patients With Emotional Disorders

OBJECTIVE

To assess the correlation between the incidence of non-erosive reflux disease (NERD) and mental and psychological factors, deepen the understanding of the pathogenesis of NERD and explore effective treatments.

METHODS

NERD patients with mood disorders who met the inclusion criteria were randomly divided into a drug treatment group, a psychotherapy group, and a psychotherapy combined with drug treatment group. Before and after treatment, the patients were retrospectively analyzed using the gastroesophageal reflux disease Questionnaire, Hamilton Depression Scale, Hamilton Anxiety Scale, and SF-36 Quality of Life Scale.

RESULTS

All three treatments were found to relieve patients' symptoms and improve their quality of life to some extent. The psychotherapy combined with drug treatment group showed the best overall curative effect. The Hamilton Depression and Anxiety Scale scores were significantly lower in the psychotherapy-alone group and psychotherapy combined with drug treatment group than in the drug treatment alone group at 4, 8, and 12 weeks (P < 0.05).

CONCLUSION

Medication, psychotherapy, and psychotherapy combined with medication can relieve clinical symptoms and improve quality of life to varying degrees in patients with NERD.

Drugs for improving esophageal mucosa defense: where are we now and where are we going?

In the past, the attention of physiologists and doctors has been mainly focused on the key role of acid in the pathogenesis of gastroesophageal reflux disease (GERD), but increasing evidence that 20-40% of reflux patients respond not at all or only partially to proton pump inhibitors (PPIs) has underlined the concept that factors other than acid are implicated in its development and the elicitation of symptoms. Among these, impaired mucosal integrity, particularly in most patients with non-erosive reflux disease, has recently been reincluded and the reinforcement of defensive mechanisms and/or its protection has been reappointed as a renewed therapeutic target for the management of GERD patients. In this review we will summarize the existing knowledge of the old and novel compounds able to produce this therapeutic effect, including sucralfate, alginate-based drugs, and a new medical device consisting of hyaluronic acid and chondroitin sulfate dispersed in a bioadhesive carrier, together with the potential indications for their use. It is to be stressed, however, that, although these compounds may represent a real alternative to PPI therapy in GERD, the combination of mucosal protection with acid suppression may help manage many cases with a partial or unsatisfactory response to PPIs alone.

Exploration of the Esophageal Mucosal Barrier in Non-Erosive Reflux Disease

In the absence of visible mucosal damage, it is hypothesized that the esophageal mucosal barrier is functionally impaired in patients with non-erosive reflux disease (NERD). The aim of the present study was to perform an exploratory analysis of the mucosal barrier in NERD compared to erosive esophagitis (EE) and controls. A second aim was to explore TRPV1 gene transcription in relation to the mucosal barrier function and heartburn symptoms. In this prospective study, 10 NERD patients, 11 patients with active erosive esophagitis and 10 healthy volunteers were included. Biopsies from non-eroded mucosa were obtained for (1) ex vivo analyses (Ussing chamber) of transepithelial electrical resistance (TEER) and permeability (2) gene transcription of tight-junction proteins and transient receptor potential vanilloid subfamily member 1 (TRPV1). No differences in TEER or permeability were found between NERD and healthy volunteers, whereas TEER was lower in patients with erosive esophagitis. TRPV1 gene transcription was not significantly different between EE, NERD and controls. Conclusions: esophageal mucosal barrier function and TRPV1 transcription is not significantly altered in NERD patients. Future research is needed to explore other potential mechanisms that may account for the high symptom burden in these patients.

Impairment of chemical clearance and mucosal integrity distinguishes hypersensitive esophagus from functional heartburn

BACKGROUND

Hypersensitive esophagus (HE) is defined by endoscopy-negative heartburn with a normal acid exposure time but positive symptom association probability (SAP) and/or symptom index (SI) on impedance-pH monitoring, and proton pump inhibitor (PPI) responsiveness. Functional heartburn (FH) is distinguished by negative SAP/SI and PPI refractoriness. The clinical value of SAP and SI has been questioned. We aimed to investigate whether impairment of chemical clearance and of mucosal integrity, expressed by the postreflux swallow-induced peristaltic wave (PSPW) index and the mean nocturnal baseline impedance (MNBI), characterize HE independently of SAP and SI.

METHODS

Impedance-pH tracings from PPI-responsive endoscopy-negative patients, 125 with nonerosive reflux disease and 108 with HE, distinguished by an abnormal and a normal acid exposure time, and from 70 patients with FH were retrospectively selected and blindly reviewed.

RESULTS

The mean PSPW index and MNBI were significantly lower in nonerosive reflux disease (30 %, 1378 Ω) than in HE (51 %; 2274 Ω) and in both of them as compared with FH (76 %; 3445 Ω) (P = 0.0001). Both the PSPW index (adjusted odds ratio 0.863, P = 0.001) and the MNBI (adjusted odds ratio 0.998, P = 0.001) were independent predictors of HE; with their combined assessment, the area under the curve on receiver operating characteristic analysis was 0.957. SAP and/or SI was positive in 67 of the 108 HE patients (62 %), whereas the PSPW index and/or MNBI was abnormal in 99 of the 108 HE patients (92 %; P < 0.0001).

CONCLUSIONS

HE is characterized by impairment of chemical clearance and mucosal integrity, which explains the increased reflux perception. When SAP and SI afford uncertain results, the PSPW index and MNBI should be analyzed.

Gaseous mediators nitric oxide and hydrogen sulfide in the mechanism of gastrointestinal integrity, protection and ulcer healing

Nitric oxide (NO) and hydrogen sulfide (H2S) are known as biological messengers; they play an important role in human organism and contribute to many physiological and pathophysiological processes. NO is produced from l-arginine by constitutive NO synthase (NOS) and inducible NOS enzymatic pathways. This gaseous mediator inhibits platelet aggregation, leukocyte adhesion and contributes to the vessel homeostasis. NO is known as a vasodilatory molecule involved in control of the gastric blood flow (GBF) and the maintenance of gastric mucosal barrier integrity in either healthy gastric mucosa or that damaged by strong irritants. Biosynthesis of H2S in mammals depends upon two enzymes cystathionine-β-synthase and cystathionine γ-lyase. This gaseous mediator, similarly to NO and carbon monoxide, is involved in neuromodulation, vascular contractility and anti-inflammatory activities. For decades, H2S has been known to inhibit cytochrome c oxidase and reduce cell energy production. Nowadays it is generally considered to act through vascular smooth muscle ATP-dependent K+ channels, interacting with intracellular transcription factors and promote sulfhydration of protein cysteine moieties within the cell, but the mechanism of potential gastroprotective and ulcer healing properties of H2S has not been fully explained. The aim of this review is to compare current results of the studies concerning the role of H2S and NO in gastric mucosa protection and outline areas that may pose new opportunities for further development of novel therapeutic targets.

Electrical stimulation therapy for gastroesophageal reflux disease

Electrical stimulation therapy (EST) of the lower esophageal sphincter is a relatively new technique for the treatment of gastroesophageal reflux disease (GERD) that may address the need of GERD patients, unsatisfied with acid suppressive medication and concerned with the potential risks of surgical fundoplication. In this paper we review available data about EST for GERD, including the development of the technique, implant procedure, safety and results from open-label trials. Two short-term temporary stimulation and long-term open-label human trials each were initiated to investigate the safety and efficacy of EST for the treatment of GERD and currently up to 2 years follow-up results are available. The results of EST are promising as the open-label studies have shown that EST is a safe technique with a significant improvement in both subjective outcomes of symptoms and objective outcomes of esophageal acid exposure in patients with GERD. However, long-term data from larger number of patients and a sham-controlled trial are required before EST can be conclusively advised as a viable treatment option for GERD patients.