Significant increase of esophageal mucin secretion in patients with reflux esophagitis after healing with rabeprazole: its esophagoprotective potential

Proton Pump Inhibitors Modulate Gene Expression Profile in Esophageal Mucosa and Microbiome

OBJECTIVE

Proton pump inhibitors (PPIs) are commonly used to manage children with upper gastrointestinal symptoms and without a formal diagnosis. We investigated the effect of PPIs on esophageal mucosal transcriptome and active microbiota in children with normal esophagi. Furthermore, we examined whether the differences in host esophageal mucosal gene expression were driven by an underlying esophageal epithelial cell type composition.

METHODS

Using metatranscriptomics, the host transcriptional and active microbial profiles were captured from 17 esophageal biopsy samples (PPI naïve [PPI-], n = 7; PPI exposed [PPI+], n = 10) collected from children without any endoscopic and histologic abnormalities in their esophagus (normal esophagus). Deconvolution computational analysis was performed with xCell to assess if the observed epithelial gene expression changes were related to the cell type composition in the esophageal samples.

RESULTS

The median (IQR) age of our cohort was 14 years (12-16) with female (63%) preponderance. Both groups were similar in terms of their demographics and clinical features. Compared with PPI-, the PPI+ had upregulation of 27 genes including the MUC genes. The cell type composition was similar between the PPI- and PPI+ groups. Prevotella sp and Streptococcus sp were abundant in PPI+ group.

CONCLUSIONS

In children with normal esophagus, PPI exposure can be associated with upregulation of esophageal mucosal homeostasis and epithelial cell function genes in a cell-type independent manner, and an altered esophageal microbiome. Additional studies are warranted to validate our findings and to investigate the causal effect of PPIs on the normal esophageal epithelium and microbial communities.

Deprescribing and Optimal Selection of Proton Pump Inhibitors (Contributions of the 26th United Russian Gastroenterology Week)

Aim. Presentation of the Forum “Deprescribing and optimal selection of proton pump inhibitors” held in Moscow on 29 September 2020 during the 26th United Russian Gastroenterology Week.Key points. The Forum was aimed at discussing issues associated with improving the proton pump inhibitor (PPIs) therapy in treatment and prevention of acid-related diseases and upper gastrointestinal tract (GIT) disorders induced by non-steroidal anti-inflammatory drugs (NSAIDs) and antiplatelet medications. Deprescribing is considered to be an effective strategy of a motivated reduction of the PPI dosage, duration of therapy and the patient’s transfer from a regular to on-demand intake regimen. The choice of PPI may condition an optimal therapy for acid-related diseases.Conclusion. PPIs prevail in therapies for acid-related diseases and NSAID-induced upper GIT lesions. PPI deprescribing should be a strategy of choice if medically indicated. A non-enzymatic metabolism, high acid suppression, stable antisecretory effect from day 1 of therapy and cytoprotective action justify the application of rabeprazole (Pariet®) for optimising therapies for acid-related diseases and implementing the deprescribing strategy.

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

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

Modern achievements in the diagnosis and treatment of the refractory gastroesophageal reflux disease

Purpose of the review to present up-to-date data on the causes, methods of diagnosis and treatment of the refractory form of gastroesophageal reflux disease (GERD). Refractory GERD is the preservation of typical symptoms of the disease and/or incomplete healing of the esophageal mucosa against the background of taking a standard dose of proton pump inhibitors (PPI) once a day for 8 weeks. The reasons for the lack of response to the treatment are divided into related to the patient, related to therapy, and not related to GERD. Diagnostic approaches include x-ray examination of the esophagus and stomach, endoscopy with biopsy, 24-hour Impedance-pH monitoring, esophageal manometry. Depending on the reasons for the lack of response to the therapy, treatment may include lifestyle changes, doubling the dose of PPI, replacing PPI with another, adding H2-receptor antagonists, prokinetics, antacids, alginates and adsorbents. If conservative treatment is ineffective, it is possible to consider alternative methods, such as surgical treatment. Refractory GERD is a serious clinical problem. The absence of an answer to 8-week therapy with PPI requires a thorough differential diagnosis using additional examination methods. The identification of the causes of refractory to the therapy allows to optimize the approaches to its overcoming and to choose the optimal treatment.

Mucin Expression in the Esophageal Malignant and Pre-malignant States: A Systematic Review and Meta-analysis

BACKGROUND

Mucins are heavily glycosylated glycoproteins, synthesized by mucosal surfaces and have an important role in healthy state and malignant diseases. Change in mucins synthesis or secretion may be primary event or secondary to inflammation or carcinogenesis.

AIM

The aim of this study is to assess the current knowledge about mucin expression in esophageal lesions, and to establish a role for different mucin expressions as prognostic markers.

METHOD

English Medical literature searches were conducted for "mucin" and "esophagus." Observational studies were included. Meta-analysis was performed using comprehensive meta-analysis software. Pooled odds ratios (OR) and 95% confidence intervals (CI) were calculated.

RESULTS

In the random-effect model, mucin expression was significantly higher in esophageal lesions than in normal esophageal mucosa with OR=5.456 (95% CI, 1.883-15.807, P=0.002). Measure of heterogeneity, demonstrated in the included studies, was high: Q=287.501, df (Q)=44.00, P<0.0001, I=84.696%. There is a gradient of mucin expression and complexity in esophageal premalignant to malignant lesions, lower in Barrett's mucosa with low grade dysplasia (LGD), increased in high grade dysplasia (HGD), and highest in esophageal adenocarcinoma (EAC). MUC2, MUC3, MUC5AC, and MUC6 expression was higher in EAC than HGD, and higher in HGD than in LGD mucosa. The opposite was found for MUC1 and MUC4.

CONCLUSION

Increased expression of certain mucin genes in esophageal mucosa may be further studied as a potential diagnostic tool, and this may add important information in the surveillance of Barrett's esophagus.

Does the healing of the esophageal mucosa improve the function of the esophageal submucosal and salivary glands?

The esophageal pre-epithelial barrier encompasses components of secretions from both the esophageal submucosal and salivary glands. We demonstrated, in patients with reflux esophagitis (RE), significantly diminished luminal release of esophageal epidermal growth factor (EGF). The rate of luminal release of esophageal prostaglandin E₂ (PGE₂ ) was significantly higher compared with controls and significantly declined after healing of RE. Patients with RE also exhibited significant declines in esophageal mucin secretion; however, after healing of RE with rabeprazole, this rate increased significantly. The rate of salivary EGF and bicarbonate secretion in patients with RE was significantly lower than in controls. We have demonstrated that mastication of tasteless parafilm, which could be substituted with sugarless chewing gum in the clinical scenario, resulted in profound and significant increases in the rate of secretion of salivary protective factors, such as bicarbonate, mucin, protein, EGF, and PGE₂ , in patients with RE. Our data clearly indicate that there is a relationship between the form or the structure of the esophageal mucosa and the secretory function of not only the esophageal submucosal glands but also the salivary glands. Application of masticatory stimulation in a clinical scenario may also have some therapeutic potential.

The role of mucin in GERD and its complications

Acid, pepsin and other noxious material reach the esophageal mucosa and interact with the luminal aspect of the squamous epithelium. The first protective barrier to these potentially injurious substances is the mucus buffer layer that covers the mucosa. In healthy people, the esophagus has a protective surface adherent mucus gel barrier. Levels of mucin glycoprotein are considerably increased in response to acid and pepsin. A wide spectrum of mucin genes are expressed in normal esophageal mucosa, squamous cell carcinoma of the esophagus, Barrett epithelium and esophageal adenocarcinoma. The mucins MUC5AC and MUC6 are expressed to a similar degree in Barrett metaplasia and gastric mucosa, as is MUC2 in Barrett intestinal metaplasia and small bowel mucosa. Increased expression of MUC1 is associated with progression from dysplasia to adenocarcinoma of the esophagus. Thus, mucins have an important role in the defense of esophageal mucosa against the acid, pepsin and bile that are present in the refluxate. Changes in the expression of mucins occur in patients with GERD, and might lead to the development of new drugs.