The Esophageal and Gastric Microbiome in Health and Disease

Dysbiosis of the Upper Gastrointestinal Tract in Head-and-Neck Cancer Survivors: A Pilot Study Using the Capsule Sponge Device

BACKGROUND

A non-endoscopic capsule-sponge device allows sampling the entire length of the esophagus. Here, we compared microbiomes of the oral cavity, esophagus, and gastric corpus collected by oral swab, capsule-sponge device, and endoscopic biopsy, respectively, in patients representing three distinct risk profiles for esophageal squamous cell carcinoma (ESCC).

METHODS

The study enrolled 11 patients with esophageal squamous intraepithelial neoplasia, 21 patients after curative treatment for head and neck squamous cell cancer (HNSCC) (HNSCC survivors), and 40 patients with functional dyspeptic (FD) symptoms. Microbial genomic DNA was analyzed using 16S rRNA gene amplicon sequencing.

RESULTS

The Shannon index of the capsule-sponge sample microbiota was significantly higher in FD group than in patients after treatment for HNSCC, and the Chao index of gastric samples differed between HNSCC survivors and FD patients. Analysis of the β-diversity of FD patients, HNSCC, and esophageal squamous intraepithelial neoplasia showed that different genera formed at each location. The abundance of 205, 116, and 9 genera differed between FD patients and HNSCC survivors in the gastric, capsule-sponge, and oral samples, respectively; 33 genera differed between the FD group and patients with esophageal squamous intraepithelial neoplasia in capsule-sponge samples.

CONCLUSIONS

The bacterial communities of the upper digestive tract were clustered according to the anatomic site. Despite substantial differences in gastric and esophageal microbiota samples between FD patients and HNSCC survivors, the microbial members and diversity showed small differences between FD patients and those with esophageal squamous intraepithelial neoplasia. It remains unclear whether gastric and esophageal dysbiosis is associated with or is a consequence of treatment for HNSCC.

Analysis of the gut microbiota in children with gastroesophageal reflux disease using metagenomics and metabolomics

Background

There is no direct evidence of gut microbiota disturbance in children with gastroesophageal reflux disease (GERD). This study aimed to provide direct evidence and a comprehensive understanding of gut microbiota disturbance in children with GERD through combined metagenomic and metabolomic analysis.

Methods

30 children with GERD and 30 healthy controls (HCs) were continuously enrolled, and the demographic and clinical characteristics of the subjects were collected. First, 16S rRNA sequencing was used to evaluate differences in the gut microbiota between children with GERD and HC group, and 10 children with GERD and 10 children in the HC group were selected for metagenomic analysis. Nontargeted metabolomic analysis was performed using liquid chromatography/mass spectrometry (LC/MS), and metagenomic and metabolomic data were analyzed together.

Results

There were significant differences in the gut microbiota diversity and composition between children with GERD and HCs. The dominant bacteria in children with GERD were Proteobacteria and Bacteroidota. At the species level, the top three core bacterial groups were Bacteroides stercoris, Bacteroides vulgatus and Alistipes putredinis. The main differential pathways were identified to be related to energy, amino acid, vitamin, carbohydrate and lipid metabolism. LC/MS detected 288 different metabolites in the positive and negative ion modes between children with GERD and HCs, which were mainly involved in arachidonic acid (AA), tyrosine, glutathione and caffeine metabolism.

Conclusion

This study provides new evidence of the pathogenesis of GERD. There are significant differences in the gut microbiota, metabolites and metabolic pathways between HCs and children with GERD, and the differences in metabolites are related to specific changes in bacterial abundance. In the future, GERD may be treated by targeting specific bacteria related to AA metabolism.

Dynamic variations of the gastric microbiota: Key therapeutic points in the reversal of Correa's cascade

Correa's cascade is a dynamic process in the development of intestinal-type gastric cancer (GC), and its pathological features, gastric microbiota and interactions between microorganisms and their hosts vary at different developmental stages. The characteristics of cells, tissues and gastric microbiota before or after key therapeutic points are critical for monitoring malignant transformation and early tumour reversal. This review summarises the pathological features of gastric mucosa, characteristics of gastric microbiota, specific microbial markers, microbe-microbe interactions and microbe-host interactions at different stages in Correa's cascade. The markers related to each Correa's cascade point were analysed in detail. We attempted to identify key therapeutic points for early cancer reversal and provide a novel approach to reduce the incidence of GC and improve precise treatment.

The Gut Microbiome and Its Implication in the Mucosal Digestive Disorders

The gastrointestinal (GI) tract is one of the most studied compartments of the human body as it hosts the largest microbial community including trillions of germs. The relationship between the human and its associated flora is complex, as the microbiome plays an important role in nutrition, metabolism and immune function. With a dynamic composition, influenced by many intrinsic and extrinsic factors, there is an equilibrium maintained in the composition of GI microbiota, translated as "eubiosis". Any disruption of the microbiota leads to the development of different local and systemic diseases. This article reviews the human GI microbiome's composition and function in healthy individuals as well as its involvement in the pathogenesis of different digestive disorders. It also highlights the possibility to consider flora manipulation a therapeutic option when treating GI diseases.

Salivary microbiota composition may discriminate between patients with eosinophilic oesophagitis (EoE) and non-EoE subjects

BACKGROUND

Data on the role of the microbiome in adult patients with eosinophilic oesophagitis (EoE) are limited.

AIMS

To prospectively collect and characterise the salivary, oesophageal and gastric microbiome in patients with EoE, further correlating the findings with disease activity.

METHODS

Adult patients with symptoms of oesophageal dysfunction undergoing upper endoscopy were consecutively enrolled. Patients were classified as EoE patients, in case of more than 15 eosinophils per high-power field, or non-EoE controls, in case of lack of eosinophilic infiltration. Before and during endoscopy, saliva, oesophageal and gastric fundus biopsies were collected. Microbiota assessment was performed by 16 s rRNA analysis. A Sparse Partial Least Squares Discriminant Analysis (sPLS-DA) was implemented to identify biomarkers.

RESULTS

Saliva samples were collected from 29 EoE patients and 20 non-EoE controls;, biopsies from 25 EoE and 5 non-EoE controls. In saliva samples, 23 Amplicon Sequence Variants (ASVs) were positively associated with EoE and 27 ASVs with controls, making it possible to discriminate between EoE and non-EoE patients with a classification error (CE) of 24%. In a validation cohort, the accuracy, sensitivity, specificity, positive predictive value and negative predictive value of this model were 78.6%, 80%, 75%, 80% and 60%, respectively. Moreover, the analysis of oesophageal microbiota samples observed a clear microbial pattern able to discriminate between active and inactive EoE (CE = 8%).

CONCLUSION

Our preliminary data suggest that salivary metabarcoding analysis in combination with machine learning approaches could become a valid, cheap, non-invasive test to segregate between EoE and non-EoE patients.

Liposome Delivery of Nucleic Acids in Bacteria: Toward In Vivo Labeling of Human Microbiota

Development of specific probes to study the in vivo spatial distribution of microorganisms is essential to understand the ecology of human microbiota. Herein, we assess the possibility of using liposomes loaded with fluorescently labeled nucleic acid mimics (LipoNAMs) to image Gram-negative and Gram-positive bacteria. We proved that liposome fusion efficiencies were similar in both Gram-negative and Gram-positive bacteria but that the efficiency was highly dependent on the lipid concentration. Notably, LipoNAMs were significantly more effective for the internalization of oligonucleotides in bacteria than the fixation/permeabilization methods commonly used in vitro. Furthermore, a structural and morphological assessment of the changes on bacteria allowed us to observe that liposomes increased the permeability of the cell envelope especially in Gram-negative bacteria. Considering the delivery efficiency and permeabilization effect, lipid concentrations of approximately 5 mM should be selected to maximize the detection of bacteria without compromising the bacterial cellular structure.

Unveiling microbiome profiles in human inner body fluids and tumor tissues with pancreatic or biliary tract cancer

With the discovery of bacterial symbiosis in the tissues of various cancers, the study of the tumor microbiome is attracting a great deal of attention. Anatomically, since the gastrointestinal tract, liver, and pancreas form a continuous ductal structure, the microbiomes in the digestive juices of these organs may influence each other. Here, we report a series of microbiome data in tumor-associated tissues such as tumor, non-tumor, and lymph nodes, and body fluids such as saliva, gastric juice, pancreatic juice, bile, and feces of patients with pancreatic or biliary tract cancers. The results show that the microbiome of tumor-associated tissues has a very similar bacterial composition, but that in body fluids has different bacterial composition which varies by location, where some bacteria localize to specific body fluids. Surprisingly, Akkermansia was only detected in the bile of patients with biliary tract cancer and its presence was significantly associated with the performance of external biliary drainage (P = 0.041). Furthermore, we found that tumor-associated tissues and body fluids in deep inner body are mostly inhabited by unidentified and uncharacterized bacteria, suggesting that such bacteria may be potential targets for precision therapy in the future.

Esophageal Microbiota and Nutritional Intakes in Patients With Achalasia Before and After Peroral Endoscopic Myotomy

Background/Aims

The composition of the microbiota in the esophagus is only partially understood, especially in patients with achalasia. We aim to investigate the esophageal microbial community and nutritional intakes in patients with achalasia before and after peroral endoscopic myotomies (POEM).

Methods

Twenty-nine patients were prospectively enrolled from 4 referral institutions across Korea. We collected esophageal samples (mucosal biopsies and retention fluid) and conducted dietary surveys for nutritional intake before and 8 weeks after POEM. The esophageal microbiota was analyzed by 16S rRNA gene sequencing targeting the V3-V4 region.

Results

Out of the 105 samples from 29 patients, 99 samples were subjected to microbial bioinformatic analysis after quality control, which excluded samples with no amplification or low-quality sequence data. The overall esophageal microbial compositions of patients with achalasia showed that Firmicutes, Bacteroidetes, Proteobacteria, Actinobacteria, and Fusobacteria were the dominant phyla, representing over 95% of the total phyla in all groups. At the genus level, Streptococcus was the most abundant in all groups. The observed operational taxonomic unit number was significantly higher in the retention fluid than in the tissue biopsies. However, the esophageal microbial composition showed no significant changes 8 weeks post POEM. The dietary survey analysis showed that nutritional intake significantly improved post POEM.

Conclusion

This study determined the unique esophageal microbial composition of patients with achalasia, and also found that the microbial composition did not significantly change after POEM in the short-term, despite a significant improvement in the nutritional intake.

Pathophysiology of Pediatric Gastroesophageal Reflux Disease: Similarities and Differences With Adults

Gastroesophageal reflux (GOR) is defined as "the passage of gastric contents into the esophagus with or without regurgitation and vomiting" and gastroesophageal reflux disease (GORD) is defined "when GOR leads to troublesome symptoms affecting the daily functioning and/or complications." This definition was first developed in 2006 by the Montreal consensus group (1) and later on adopted by pediatric gastroenterology societies such as ESPGHAN and NASPGHAN in 2009 (2). The definition of gastroesophageal reflux reveals little about its pathophysiology and is focused on symptomatology. In this way, it acts as an umbrella term for the multifactorial causes of the disease and the various phenotypes encountered; from functional heartburn to hypersensitive esophagus and nonerosive reflux disease, to erosive esophagitis and Barrett's esophagus. This article is devoted to the pathophysiology of pediatric GORD in comparison to adult GORD and is divided in 2 parts. In the first part, we will systematically describe the different mechanisms for the generation and clearance of reflux events, while on the second part we will discuss the mechanisms involved in symptoms generation. Finally, we will discuss the similarities and differences between pediatric and adult GORD.

Fusobacterium nucleatum predicts a high risk of metastasis for esophageal squamous cell carcinoma

Background

Esophageal squamous cell carcinoma (ESCC) is the major type of esophageal cancer in China. The role of the bacteria present in ESCC tissue in neoplastic progression has not been fully elucidated. This study aimed to uncover different bacterial communities in ESCC tissues and examine the correlation between the abundance of the esophageal flora and clinicopathologic characteristics of ESCC.

Results

Microorganisms in tumors and normal tissues showed obvious clustering characteristics. The abundance of Fusobacterium (P = 0.0052) was increased in tumor tissues. The high level of Fusobacterium nucleatum was significantly associated with pT stage (P = 0.039) and clinical stage (P = 0.0039). The WES data showed that COL22A1, TRBV10–1, CSMD3, SCN7A and PSG11 were present in only the F. nucleatum-positive ESCC samples. GO and protein domain enrichment results suggested that epidermal growth factor might be involved in the regulation of cell apoptosis in F. nucleatum-positive ESCC. Both a higher mutational burden and F. nucleatum-positive was observed in tumors with metastasis than in tumors without metastasis.

Conclusion

F. nucleatum is closely related to the pT stage and clinical stage of ESCC. The abundance of F. nucleatum and tumor mutation burden may be used in combination as a potential method to predict metastasis in ESCC.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12866-021-02352-6.

The gastric microbiota in patients with Crohn's disease; a preliminary study

The gastric microbiota in Crohn's disease (CD) has not been studied. The purpose of the study was to evaluate differences of stomach microbiota between CD patients and controls. DNA was extracted from gastric mucosal and fluid samples, from 24 CD patients and 19 controls. 16S rRNA gene sequencing identified 1511 operational taxonomic units (OTUs), of which 239 passed the low abundance and low variance filters. All but one CD patients were HP negative. Fifteen bacterial phyla were identified in at least one mucosal or fluid site. Of these, Bacteroidota and Firmicutes accounted for 70% of all phyla. Proteobacteria, Actinobacteriota, and Fusobacteriota combined accounted for 27%. There was significant difference in the relative abundance of Bacteroidota, Proteobacteria, Fusobacteriota, and Campilobacterota between CD patients and controls only in gastric corpus samples. In gastric liquid, there was a significant difference only in Actinobacteriota. Pairwise comparison identified 67 differentially abundant OTUs in at least one site. Of these, 13 were present in more than one comparison, and four differentiating OTUs (Neisseriaceae, Neisseria, Absconditabacteriales, and Microbacteriaceae) were identified at all tested sites. The results reveal significant changes in gastric microbial profiles (beta diversity, phylum, and individual taxa levels) between H. pylori-negative CD patients and controls.

Immune system and microbiome in the esophagus: implications for understanding inflammatory diseases

The gastrointestinal tract is the largest compartment of the body's immune system exposed to microorganisms, structural components and metabolites, antigens derived from the diet, and pathogens. Most studies have focused on immune responses in the stomach, the small intestine, and the colon, but the esophagus has remained an understudied anatomic immune segment. Here, we discuss the esophagus' anatomical and physiological distinctions that may account for inflammatory esophageal diseases.

Intragastric Administration of Casein Leads to Nigrostriatal Disease Progressed Accompanied with Persistent Nigrostriatal-Intestinal Inflammation Activited and Intestinal Microbiota-Metabolic Disorders Induced in MPTP Mouse Model of Parkinson's Disease

Gut microbial dysbiosis and alteration of gut microbiota composition in Parkinson's disease (PD) have been increasingly reported, no recognized therapies are available to halt or slow progression of PD and more evidence is still needed to illustrate its causative impact on gut microbiota and PD and mechanisms for targeted mitigation. Epidemiological evidence supported an association between milk intake and a higher incidence of Parkinson's disease (PD), questions have been raised about prospective associations between dietary factors and the incidence of PD. Here, we investigated the significance of casein in the development of PD. The mice were given casein (6.75 g/kg i.g.) for 21 days after MPTP (25 mg/kg i.p. × 5 days) treatment, the motor function, dopaminergic neurons, inflammation, gut microbiota and fecal metabolites were observed. The experimental results revealed that the mice with casein gavage after MPTP treatment showed a persisted dyskinesia, the content of dopamine in striatum and the expression of TH in midbrain and ileum were decreased, the expression of Iba-1, CD4, IL-22 in midbrain and ileum increased continuously with persisted intestinal histopathology and intestinal barrier injury. Decreased intestinal bile secretion in addition with abnormal digestion and metabolism of carbohydrate, lipids and proteins were found, whereas these pathological status for the MPTP mice without casein intake had recovered after 24 days, no significant differences were observed with regard to only treated with casein. Our study demonstrates that intestinal pathologic injury, intestinal dysbacteriosis and metabolism changes promoted by casein in MPTP mice ultimately exacerbated the lesions to dopaminergic neurons.

Role of Short Chain Fatty Acids and Apolipoproteins in the Regulation of Eosinophilia-Associated Diseases

Eosinophils are key components of our host defense and potent effectors in allergic and inflammatory diseases. Once recruited to the inflammatory site, eosinophils release their cytotoxic granule proteins as well as cytokines and lipid mediators, contributing to parasite clearance but also to exacerbation of inflammation and tissue damage. However, eosinophils have recently been shown to play an important homeostatic role in different tissues under steady state. Despite the tremendous progress in the treatment of eosinophilic disorders with the implementation of biologics, there is an unmet need for novel therapies that specifically target the cytotoxic effector functions of eosinophils without completely depleting this multifunctional immune cell type. Recent studies have uncovered several endogenous molecules that decrease eosinophil migration and activation. These include short chain fatty acids (SCFAs) such as butyrate, which are produced in large quantities in the gastrointestinal tract by commensal bacteria and enter the systemic circulation. In addition, high-density lipoprotein-associated anti-inflammatory apolipoproteins have recently been shown to attenuate eosinophil migration and activation. Here, we focus on the anti-pathogenic properties of SCFAs and apolipoproteins on eosinophil effector function and provide insights into the potential use of SCFAs and apolipoproteins (and their mimetics) as effective agents to combat eosinophilic inflammation.

Helicobacter pylori: Commensal, symbiont or pathogen?

This review considers the data on Helicobacter pylori (H. pylori), which have been accumulated over 40 years since its description as an etiological factor in gastrointestinal diseases. The majority of modern publications are devoted to the study of the pathogenic properties of the microorganism in the development of chronic gastritis, peptic ulcer disease, and gastric cancer, as well as methods for its eradication. However, in recent years, there have been more and more studies which have suggested that H. pylori has a beneficial, or potentially positive, effect on the human body. The authors have attempted to objectively analyze the information accumulated in the literature on H. pylori. Some studies consider it as one of the recently identified human bacterial pathogens, and special attention is paid to the evidence suggesting that it is probably part of the composition of the human microbiome as a commensal (commensal from French to English is a table companion) or even a symbiont. The presented data discussing the presence or absence of the effect of H. pylori on human health suggest that there is an apparent ambiguity of the problem. The re-assessment of the data available on H. pylori infection is important in order to answer the question of whether it is necessary to create a program of mass H. pylori eradication or to apply a more personalized approach to treating patients with H. pylori-associated gastrointestinal diseases and to perform eradication therapy.

Food Processing, Dysbiosis, Gastrointestinal Inflammatory Diseases, and Antiangiogenic Functional Foods or Beverages

Foods and beverages provide nutrients and alter the gut microbiota, resulting in eubiosis or dysbiosis. Chronic consumption of a diet that is high in saturated or trans fats, meat proteins, reducing sugars, and salt and low in fiber induces dysbiosis. Dysbiosis, loss of redox homeostasis, mast cells, hypoxia, angiogenesis, the kynurenine pathway, transglutaminase 2, and/or the Janus kinase pathway are implicated in the pathogenesis and development of inflammatory bowel disease, celiac disease, and gastrointestinal malignancy. This review discusses the effects of oxidative, carbonyl, or glycative stress-inducing dietary ingredients or food processing-derived compounds on gut microbiota and gastrointestinal epithelial and mast cells as well as on the development of associated angiogenic diseases, including key signaling pathways. The preventive or therapeutic potential and the biochemical pathways of antiangiogenic or proangiogenic foods or beverages are also described. The outcomes of the interactions between disease pathways and components of food are critical for the design of foods and beverages for healthy lives.

Microbiome of the Aerodigestive Tract in Health and Esophageal Disease

The diverse human gut microbiome is comprised of approximately 40 trillion microorganisms representing up to 1000 different bacterial species. The human microbiome plays a critical role in gut epithelial health and disease susceptibility. While the interaction between gut microbiome and gastrointestinal pathology is increasingly understood, less is known about the interaction between the microbiome and the aerodigestive tract. This review of the microbiome of the aerodigestive tract in health, and alterations in microbiome across esophageal pathologies highlights important findings and areas for future research. First, microbiome profiles are distinct along the aerodigestive tract, spanning the oral cavity to the stomach. In patients with reflux-related disease such as gastro-esophageal reflux disease, Barrett's esophagus, and esophageal adenocarcinoma, investigators have observed an overall increase in gram negative bacteria in the esophageal microbiome compared to healthy individuals. However, whether differences in microbiome promote disease development, or if these shifts are a consequence of disease remains unknown. Interestingly, use of proton pump inhibitor therapy is also associated with shifts in the microbiome, with distinct shifts and patterns along the aerodigestive tract. The relationship between the human gut microbiome and esophageal pathology is a ripe area for investigation, and further understanding of these pathways may promote development of novel targets in prevention and therapy for esophageal diseases.

Gastrointestinal Disorders and Risk of First-Ever Ischemic Stroke

BACKGROUND AND PURPOSE

Recent studies suggest that alteration of the normal gut microbiome contributes to atherosclerotic burden and cardiovascular disease. While many gastrointestinal diseases are known to cause disruption of the normal gut microbiome in humans, the clinical impact of gastrointestinal diseases on subsequent cerebrovascular disease remains unknown. We conducted an exploratory analysis evaluating the relationship between gastrointestinal diseases and ischemic stroke.

METHODS

We performed a retrospective cohort study using claims between 2008 and 2015 from a nationally representative 5% sample of Medicare beneficiaries. We included only beneficiaries ≥66 years of age. We used previously validated diagnosis codes to ascertain our primary outcome of ischemic stroke. In an exploratory manner, we categorized gastrointestinal disorders by anatomic location, disease chronicity, and disease mechanism. We used Cox proportional hazards models to examine associations of gastrointestinal disorder categories and ischemic stroke with adjustment for demographics and established vascular risk factors.

RESULTS

Among a mean of 1 725 246 beneficiaries in each analysis, several categories of gastrointestinal disorders were associated with an increased risk of ischemic stroke after adjustment for established stroke risk factors. The most notable positive associations included disorders of the stomach (hazard ratio, 1.17 [95% CI, 1.15-1.19]) and functional (1.16 [95% CI, 1.15-1.17]), inflammatory (1.13 [95% CI, 1.12-1.15]), and infectious gastrointestinal disorders (1.13 [95% CI, 1.12-1.15]). In contrast, we found no associations with stroke for diseases of the anus and rectum (0.97 [95% CI, 0.94-1.00]) or neoplastic gastrointestinal disorders (0.97 [95% CI, 0.94-1.00]).

CONCLUSIONS

In exploratory analyses, several categories of gastrointestinal disorders were associated with an increased risk of future ischemic stroke after adjustment for demographics and established stroke risk factors.

[GERD and adjuvant radio-chemotherapy predespose to recurrent voice prosthesis leakage]

After total laryngectomy, regaining ability to speech is a keystone in regards of life quality. Voice prostheses have been shown to be a sufficient tool for satisfying communication, although frequent replacements of prostheses are burdening certain patients. Therefore, a more accurate understanding of mechanisms of prosthetic leakage is urgently needed.

METHODS

We performed a retrospective analysis of 58 Patients after laryngectomy. Additionally, we analyzed pre- and post-therapeutic CT-scans of 22 Patients regarding pharyngeal stenosis.

RESULTS

In 40 Patients, at least one replacement of voice prosthesis was documented during observation period, median device life was 235 days. Patients treated with adjuvant radiotherapy (RT) showed a significantly longer device life than patients with adjuvant radio-chemotherapy (RCT, p = 0.002). Furthermore, patients suffering of gastroesophageal reflux disease (GERD) showed a significantly shortened device life (p = 0.04).17 patients (42.5 %) suffered of clinically relevant stenosis of the neopharynx, which was treated with dilatation in 14 patients (82 %) and did not affect prosthesis device life.

CONCLUSION

GERD is a risk factor for shortened voice prosthesis' device life and therefore should be treated effectively after laryngectomy. Also, adjuvant RCT predisposes a shortened device life.Stenosis is observed frequently after laryngectomy but does not affect device life when effectively treated.

Influence of microbiota on immunity and immunotherapy for gastric and esophageal cancers

Gastric and esophageal cancers are multifactorial and multistage-involved malignancy. While the impact of gut microbiota on overall human health and diseases has been well documented, the influence of gastric and esophageal microbiota on gastric and esophageal cancers remains unclear. This review will discuss the reported alteration in the composition of gastric and esophageal microbiota in normal and disease conditions, and the potential role of dysbiosis in carcinogenesis and tumorigenesis. This review will also discuss how dysbiosis stimulates local and systemic immunity, which may impact on the immunotherapy for cancer.

Helicobacter pylori Infection Aggravates Dysbiosis of Gut Microbiome in Children With Gastritis

Introduction:Helicobacter pylori infection consistently leads to chronic and low degree of inflammatory response in gastric mucosa and is closely related with gastrointestinal and extra-gastric diseases. Effects of local microbiome in the stomach have been studied in adults and children with H. pylori infection. It is, however, not known whether the intestinal microbial community differs in children with varying H. pylori infection. The aim of this study is to characterize the altered composition of microbiome induced by H. pylori infection and in gastritis.

Materials and Methods: This study involved 154 individuals, including 50 children affected by H. pylori-induced gastritis, 42 children with H. pylori-negative gastritis, and 62 healthy controls. Gut microbiome composition was analyzed using 16S rRNA gene-based pyrosequencing. Fecal bacterial diversity and composition were then compared.

Results: On the basis of an analysis of similarities and differences, we found that children with H. pylori-induced gastritis exhibited gut bacteria dysbiosis. The ratio of Firmicutes/Bacteroidetes (F:B) at the phylum level had dramatically decreased in H. pylori-positive gastritis group (HPG) and H. pylori-negative gastritis group (HNG), compared with the healthy control group (HCG). At the family and genus levels, relative abundance of Bacteroidaceae and Enterobacteriaceae was prevalent in HPG and HNG, whereas relative abundance of Lachnospiraceae, Bifidobacteriaceae, and Lactobacillaceae was seen in HCG. Prevalence of different taxa of gut microbiome at the class, order, family, and genus levels was also observed among the three groups.

Conclusions: Gastritis can cause changes in composition of fecal microbiome, which is exacerbated by H. pylori infection. These changes in gut microbiome may be related to drug resistance and development of chronic gastrointestinal diseases.

The potential role of potassium-competitive acid blockers in the treatment of gastroesophageal reflux disease

PURPOSE OF REVIEW

Gastroesophageal reflux disease (GERD) is primarily a motor disorder, but its pathogenesis is multifactorial. Although gastric acid secretion is usually normal in GERD patients, treatment with proton pump inhibitors (PPIs) has become the standard of care, despite increasing awareness of their shortcomings. In this article, a new class of antisecretory drugs (namely potassium-competitive acid blockers, P-CABs), developed to overcome these limitations, is discussed.

RECENT FINDINGS

P-CABs block the K exchange channel of the proton pump, resulting in rapid, competitive, reversible inhibition of acid secretion. These drugs offer a more rapid elevation of intragastric pH than PPIs, while maintaining similar antisecretory effect, the duration of which is dependent on half-life and can be prolonged with extended release formulations. Thus, P-CABs offer advances in the treatment of GERD including rapid heartburn relief, faster and more reliable healing of severe grades of erosive esophagitis, as a consequence of better control of nighttime acid secretion than PPIs.

SUMMARY

P-CABs overcome many of the drawbacks of PPIs. The unique antisecretory effects of vonoprazan might be especially useful in the long-term treatment of patients with Barrett's esophagus.

A Preliminary Study of Microbiota Diversity in Saliva and Bronchoalveolar Lavage Fluid from Patients with Primary Bronchogenic Carcinoma

Background

The present study aimed to evaluate the difference in microbiota diversity in the oral cavity and fluid bronchoalveolar lavage (BALF) of patients with lung cancer.

Material/Methods

Buccal (saliva) and lower respiratory tract BALF samples were collected from 51 patients with primary bronchogenic carcinoma and 15 healthy controls, and bacterial genomic DNA was extracted. High-throughput 16S rDNA amplicon sequencing was performed, and microbial diversity, composition, and functions of microbiota were analyzed by bioinformatics methods.

Results

Patients with lung cancer have lower microbial diversity than healthy controls in both saliva and BALF samples. Significant segregation was observed between the different pathological types of lung cancer groups and the control group regardless of the sampling site. Treponema and Filifactor were identified as potential bacterial biomarkers in BALF samples, while Filifactor was ideal to distinguish healthy controls from lung cancer patients. Moreover, the predictive variation analysis of the KEGG (Kyoto Encyclopedia of Genes and Genomes) metabolic pathway showed that the metabolic differences in microbiota varied by sampling site.

Conclusions

Lung cancer patients carry a different and less diverse microorganism community than healthy controls. Certain bacterial taxa might be associated with lung cancer, but the exact species depends on the sampling site and the pathological type. This study provides basic data on the microbiota diversity in BALF and saliva samples from lung cancer patients. Further investigation with a larger sample size should help validate the enriched species in different pathological types of lung cancers.

Bacterial colonization and antimicrobial resistance genes in neonatal enteral feeding tubes

Enteral feeding is a key component of care in neonatal intensive care units (NICUs); however, feeding tubes harbor microbes. These microbes have the potential to cause disease, yet their source remains controversial and clinical recommendations to reduce feeding tube colonization are lacking. This study aims to improve our understanding of the bacteria in neonatal feeding tubes and to evaluate factors that may affect these bacteria. 16S rRNA gene sequencing was used to characterize the bacteria present in pharyngeal, esophageal, and gastric portions of feeding tubes, residual fluid of the tubes, and infant stool using samples from 47 infants. Similar distributions of taxa were observed in all samples, although beta diversity differed by sample type. Feeding tube samples had lower alpha diversity than stool samples, and alpha diversity increased with gestational age, day of life, and tube dwell time. In a subset of samples from 6 infants analyzed by whole metagenome sequencing, there was greater overlap in transferable antimicrobial resistance genes between tube and fecal samples in breast milk fed infants than in formula fed infants. These findings develop our understanding of neonatal feeding tube colonization, laying a foundation for research into methods for minimizing NICU patients' exposure to antimicrobial resistant microbes.

Prebiotics and Probiotics in Digestive Health

As the importance of the gut microbiota in health and disease is increasingly recognized interest in interventions that can modulate the microbiota and its interactions with its host has soared. Apart from diet, prebiotics and probiotics represent the most commonly used substances taken in an effort to sustain a healthy microbiome or restore balance when it is believed bacterial homeostasis has been disturbed in disease. While a considerable volume of basic science attests to the ability of various prebiotic molecules and probiotic strains to beneficially influence host immune responses, metabolic processes and neuro-endocrine pathways, the evidence base from human studies leaves much to be desired. This translational gap owes much to the manner in which this sector is regulated but also speaks to the challenges that confront the investigator who seeks to explore microbiota modulation in either healthy populations or those who suffer from common digestive ailments. For many products marketed as probiotics, some of the most fundamental issues relating to quality control, such as characterization, formulation, viability safety are scarcely addressed.

Changes in the distal esophageal microbiota in Chinese patients with reflux esophagitis

OBJECTIVE

Changes in microbiota composition in the distal esophagus may be associated with the pathogenesis of gastroesophageal reflux disease. We aimed to compare the composition of distal esophageal microbiota between Chinese patients with reflux esophagitis (RE) and healthy volunteers using metagenomic high-throughput DNA sequencing and bioinformatic analyses.

METHODS

Healthy volunteers (controls) and patients with reflux esophagitis (RE) were enrolled. Distal esophageal (2 cm above the gastroesophageal junction) biopsy specimens were obtained under endoscopy. Microbial DNA was extracted from the specimens, followed by 16S rDNA gene amplification and Illumina sequencing. Bioinformatic tools were applied to dissect the community structure.

RESULTS

No dramatic differences in microbiota were found in RE patients compared with the controls. At the phylum level, only Bacteroidetes differed between the groups, being less abundant in the RE group. The overall number and diversity of species tended to be lower in RE patients, but there were no significant differences between the groups. Three genera, Prevotella, Helicobacter, and Moraxella, were obviously depleted in RE patients, as revealed by linear discriminant analysis.

CONCLUSIONS

The composition of distal esophageal microbiota in Chinese patients with RE showed moderate changes compared with healthy controls. To what extent these changes are associated with the pathogenesis of RE needs further investigation.

Analysis of culturable microbiota present in the stomach of children with gastric symptoms

Despite extensive studies on the gastric microbiota, including Helicobacter pylori and non-H. pylori, the bacterial composition in children remains unknown. In this study, we analyzed the culturable gastric bacteria in stomach biopsies from 346 children aged 1-15 years affected by gastric diseases. H. pylori and non-H. pylori were identified by specific PCR and 16S rDNA sequencing, respectively. Antibiotic susceptibilities of H. pylori and non-H. pylori were tested by the E-test and disk diffusion methods, respectively. Rapid diagnosis was also performed by H. pylori-specific PCR. Twenty-two H. pylori strains were obtained from culture, and 92 biopsies were positive by H. pylori-specific PCR. The positive rate was higher in boys (40.3%) than in girls (23.3%) (P = 0.001). Resistance rates of 22 H. pylori strains were as follows: metronidazole, 86.4%; tetracycline, 22.7%; amoxicillin, 22.7%; levofloxacin, 31.8%; clarithromycin, 36.4%. Ten isolates were multidrug-resistant. Additionally, among 366 non-H. pylori strains, 204 exhibited urease activity. Non-H. pylori resistance rates were as follows: metronidazole, 94.8%; tetracycline, 26.2%; amoxicillin, 42.6%; levofloxacin, 15.3%; clarithromycin, 46.7%. Our results showed that children with gastric disorders harbor stomach bacteria with urease activity or nitrate reductase activity. Further studies will determine the effects of non-H. pylori bacteria in gastric diseases.

Qualitative and Quantitative DNA- and RNA-Based Analysis of the Bacterial Stomach Microbiota in Humans, Mice, and Gerbils

Clinical stomach interventions, such as acid inhibition or bypass surgery, have been linked to fecal microbiota alterations. We demonstrate that the stomach microbiota largely overlaps those of adjacent gastrointestinal locations and identify gradual decreases and increases in the relative abundances of specific bacteria within the stomach, suggesting selective enrichment and depletion. Moreover, similarities between stomach and esophagus samples are proportional to the concentrations of Streptococcus (Firmicutes) in the stomach. The relative abundance of Firmicutes in the stomach, compared to that of Bacteroidetes, is increased in RNA relative to DNA, indicating higher transcriptional activity. Moreover, increased absolute bacterial loads are associated with decreased relative abundance of Firmicutes and higher relative abundance of Bacteroidetes. Our findings characterize the stomach microbiota as influenced by Bacteroidetes influx against a background of transcriptionally more active Firmicutes. Human, mouse, and gerbil stomach microbiotas differ at lower taxonomic levels, which might affect the utility of these model organisms.

Clinical interventions in the stomach have been linked to fecal microbiota alterations, suggesting a function of the stomach in gastrointestinal (GI) homeostasis. We sought to determine the taxonomic bacterial biogeography of the upper GI tract, including different sites within the human stomach (cardia, corpus, and antrum), adjacent upstream (esophagus) and downstream (duodenum) locations, and luminal contents (aspirate), as well as whole-stomach samples from mice and gerbils. Qualitative and quantitative DNA- and RNA-based taxonomic microbiota analyses were combined to study the relationship of relative and absolute bacterial abundances and transcriptionally active bacterial microbiota components in the stomach of humans and mice. Stomach microbiota compositions resembled those of esophagus and duodenum. However, along the descending GI tract, the relative abundances of specific oropharyngeal commensals decreased (Streptococcus) or increased (Rothia mucilaginosa, Porphyromonas, and Lachnospiraceae). Furthermore, the compositional similarity (weighted UniFrac) between stomach aspirates and esophageal biopsy samples increased with gastric Streptococcus relative abundance. In both human aspirate and mouse stomach samples, Firmicutes were more abundant among transcriptionally active bacteria than Bacteroidetes. The relative abundance of Firmicutes in the stomach was negatively correlated and that of Bacteroidetes was positively correlated with absolute bacterial abundance, suggesting a disproportionate increase of Bacteroidetes over Firmicutes at higher bacterial densities. Human, mouse, and gerbil stomach samples showed similarities at higher taxonomic levels but differences at lower taxonomic levels. Our findings suggest selective enrichment and depletion of specific bacterial taxa in the stomach and Firmicutes being transcriptionally more active than Bacteroidetes that increase in relative abundance with total bacterial load.

IMPORTANCE Clinical stomach interventions, such as acid inhibition or bypass surgery, have been linked to fecal microbiota alterations. We demonstrate that the stomach microbiota largely overlaps those of adjacent gastrointestinal locations and identify gradual decreases and increases in the relative abundances of specific bacteria within the stomach, suggesting selective enrichment and depletion. Moreover, similarities between stomach and esophagus samples are proportional to the concentrations of Streptococcus (Firmicutes) in the stomach. The relative abundance of Firmicutes in the stomach, compared to that of Bacteroidetes, is increased in RNA relative to DNA, indicating higher transcriptional activity. Moreover, increased absolute bacterial loads are associated with decreased relative abundance of Firmicutes and higher relative abundance of Bacteroidetes. Our findings characterize the stomach microbiota as influenced by Bacteroidetes influx against a background of transcriptionally more active Firmicutes. Human, mouse, and gerbil stomach microbiotas differ at lower taxonomic levels, which might affect the utility of these model organisms.

Helicobacter pylori the Latent Human Pathogen or an Ancestral Commensal Organism

We dedicated this review to discuss Helicobacter pylori as one of the latest identified bacterial pathogens in humans and whether its role is mainly as a pathogen or a commensal. Diseases associated with this bacterium were highly prevalent during the 19th century and gradually have declined. Most diseases associated with H. pylori occurred in individuals older than 40 years of age. However, acquisition of H. pylori occurs mainly in young children inside the family setting. Prevalence and incidence of H. pylori has had a dramatic change in the last part of the 20th century and beginning of the 21th century. In developed countries there is a clear interruption of transmission and the lowest prevalence is observed in children younger than 10 years in these countries. A similar decline is observed but not at the same level in developing countries. Here we discuss the impact of the presence or absence of H. pylori in the health status of humans. We also discuss whether it is necessary or not to establish H. pylori eradication programs on light of the current decline in H. pylori prevalence.

Pathophysiology of Gastroesophageal Reflux Disease

The pathogenesis of gastroesophageal reflux disease (GERD) is complex and involves changes in reflux exposure, epithelial resistance, and visceral sensitivity. The gastric refluxate is a noxious material that injures the esophagus and elicits symptoms. Esophageal exposure to gastric refluxate is the primary determinant of disease severity. This exposure arises via compromise of the anti-reflux barrier and reduced ability of the esophagus to clear and buffer the refluxate, leading to reflux disease. However, complications and symptoms also occur in the context of normal reflux burden, when there is either poor epithelial resistance or increased visceral sensitivity. Reflux therefore develops via alterations in the balance of aggressive and defensive forces.

Gut microbiome: a new player in gastrointestinal disease

The gastrointestinal (GI) tract harbors a diverse and host-specific gut microbial community. Whereas host-microbe interactions are based on homeostasis and mutualism, the microbiome also contributes to disease development. In this review, we summarize recent findings connecting the GI microbiome with GI disease. Starting with a description of biochemical factors shaping microbial compositions in each gut segment along the longitudinal axis, improved histological techniques enabling high resolution visualization of the spatial microbiome structure are highlighted. Subsequently, inflammatory and neoplastic diseases of the esophagus, stomach, and small and large intestines are discussed and the respective changes in microbiome compositions summarized. Finally, approaches aiming to restore disturbed microbiome compositions thereby promoting health are discussed.

Gastric microbiota: An emerging player in Helicobacter pylori-induced gastric malignancies

The complex diversity of nonpathogenic microbes that colonize the human body, known as microbiota, exert considerable effects on physiological homeostasis, and immune regulation. Helicobacter pylori (H. pylori) is a bacterium that frequently colonizes human stomach and is a major pathogenic agent for peptic ulcer diseases, gastric cancer, and mucosa-associated lymphoid tissue (MALT) lymphoma. Due to its acidic pH and peristaltic movements, the stomach has been considered a hostile environment for most microorganisms, however various commensal microorganisms are capable of colonizing the stomach to form a stomach niche. Recent pieces of evidence indicate that commensal gastric microbes or their metabolites influence the capability of H. pylori to colonize the stomach and directly modulate its pathogenicity and carcinogenic potential. In this article, we present an overview of recent advances in the understanding of H. pylori-commensal interactions in the pathogenesis and clinical evolution of H. pylori-associated gastric malignancies.

UNBS5162 inhibits the proliferation of esophageal cancer squamous cells via the PI3K/AKT signaling pathway

C‑X‑C motif chemokine ligand (CXCL) signaling has been demonstrated to be involved in cancer invasion and migration; therefore, CXCL antagonists may serve as anticancer drugs by preventing tumor proliferation. The present study aimed to investigate whether a pan antagonist of CXCLs, UNBS5162, may inhibit esophageal cancer proliferation and to identify the underlying mechanisms. Cell proliferation and cell colony formation results, which were determined by a Cell Counting Kit‑8 assay and crystal violet staining, respectively, demonstrated that UNBS5162 inhibited esophageal cancer cell proliferation. Following treatment with UNBS5162, Transwell migration and Matrigel invasion assays, and flow cytometry with Annexin V‑fluorescein isothiocyanate and propidium iodide staining, were performed to investigate cell migration, invasion and apoptosis in human esophageal cancer cells. The results indicated that invasion and migration was reduced in UNBS5162‑treated cells, while apoptosis was increased. Western blotting experiments confirmed that UNBS5162 downregulated the protein expression of proteins associated with the phosphatidylinositol 3‑kinase (PI3K)/AKT signaling pathway, including the levels of phosphorylated (p)‑AKT, p‑mechanistic target of rapamycin kinase, ribosomal protein S6 kinase β1 and cyclin D1. In addition, upregulated expression of programed cell death 4 was observed following UNBS5162 treatment. The present study demonstrated that UNBS5162 is a novel naphthalimide that may have potential therapeutic use for the prevention of esophageal cancer proliferation and metastasis via the PI3K/AKT signaling pathway.

Gastric microbiota: tracing the culprit

The gastric environment has been long time considered bacteria-free, but the discovery of Helicobacter pylori (H. pylori) in 1982 superseded this conception. Over the last decades new diagnostic methods have been developed, starting with culture-dependent and advancing to culture-independent ones. These modern techniques provide new insight into the composition and influence of this ecosystem on the entire gastrointestinal tract. H. pylori is no longer considered the only microorganism in the stomach, other non-H. pylori microbial species may populate the same environment and exercise their role. Current knowledge suggests possible links of these bacteria with gastroduodenal diseases, such as peptic ulcer and gastric cancer but most of them need further scientific evidence. This review summarizes current information on these complex interrelations between gastric microbial communities and host in health and disease.

Different frequencies of Porphyromonas gingivalis infection in cancers of the upper digestive tract

The high incidence rate of multiple carcinomas in the upper digestive tract is often explained in terms of involvement of the same underlying risk factors. It has been reported that the oral bacterium Streptococcus anginosus is associated with esophageal, gastric, and pharyngeal cancers. We previously reported occurrence of Porphyromonas gingivalis (P. gingivalis) DNA in esophagus cancer. In this study, the presence of P. gingivalis in specimens of various types of cancer from the upper digestive tract was investigated. Here we report that P. gingivalis was preferentially and frequently present in specimens of esophageal cancer as well as in those from dysplasia of the esophagus but rarely in matched noncancerous portions and are quite low or absent in cancers from the cardia or stomach. Therefore, it led us to propose that, the microorganism does not survive in conditions of high acidity. We then investigate the pH dependence of survival of P. gingivalis as well as the acid tolerance of it. We found that, exposure to acidic buffers of a wide range of pH values led to a decline in colony forming units of P. gingivalis, thus, providing a possible explanation for variations in frequencies of P. gingivalis infection in this study.