Gastric and Duodenal Microbiota in Dyspeptic Subjects

Study Overview
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Brief Summary
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The composition of gastric microbiota is determined by the status of Helicobacter pylori infection. In subjects who have never been infected by H. pylori, gastric microbiota includes various bacteria, creating ideal microbial diversity. This ideal microbial diversity is destroyed by H. pylori infection at low intragastric pH. Since it is difficult for most bacteria to proliferate within an acidic stomach, relative H. pylori abundance gives rise to microbial dysbiosis. Conversely, unideal microbial diversity is often observed in infected individuals with impaired gastric secretory ability at hypochlorhydric condition. Bacteria producing carcinogenic N-nitrosamine compounds are often detected in individuals with past or chronic H. pylori infection at high intragastric pH. Nonetheless, microbial imbalance that occurs in the earlier phase before gastric carcinognenesis is uncertain.

Detailed Description
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Dominant colonization of a specific microbiota leading to dysbiosis may lead to inflammation of the mucosa. We hypothesized that the degree of inflammation depend on the composition of microbiota. This study was aimed to define gastric and duodenal microbiota leading to abnormal histopathology. We further tried to elucidate whether the composition of duodenal microbiota is altered by gastric microbiota. Among the dyspeptic subjects who visited for upper gastrointestinal (UGI) endoscopy, subjects with drug intake (antibiotics, PPIs, laxatives, antidepressants, statins, metformin) within 3 months will be excluded. Three biopsies will performed at the greater curvature side of the mid-antrum, greater curvature side of the mid-body, and at the duodenum, respectively. Next generation sequencing analysis will be performed for 16S rRNA variable regions using the biopsied samples. Primary study endpoint is 16S rRNA sequencing findings of gastric and duodenal microbiota. Secondary endpoints are microbiota linked with higher degrees of inflammation, activity, atrophy and intestinal metaplasia based on the updated Sydney classification. Furthermore, correlation between the microbiota and endoscopy finding will be analyzed.

Official Title
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Composition of Gastric and Duodenal Microbiota in Dyspeptic Subjects

Conditions
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Microbial Colonization, Gastritis

Intervention / Treatment
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* Genetic: 16S rRNA pyrosequencing analysis


Participation Criteria
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Eligibility Criteria
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Inclusion Criteria: Dyspeptic subjects who visited for evaluation including upper gastrointestinal endoscopy and biopsies Age >20 years old Exclusion Criteria: Underlying disease(s) that requires managements Recent intake of drug(s) History of gastrectomy

Ages Eligible for Study
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Minimum Age: 20 Years

Sexes Eligible for Study
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All

Accepts Healthy Volunteers
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No

Study Plan
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How is the study designed?
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Arms and Interventions

| Participant Group/Arm | Intervention/Treatment |
| --- | --- |
| Subjects for pyrosequencing analysis<br>Dyspeptic subjects who visited for evaluation and agreed on 16S rRNA pyrosequencing analysis | Genetic: 16S rRNA pyrosequencing analysis<br>* Next generation sequencing analysis will be done for 16S rRNA V1,2 hypervariable regions at Biocore (Seoul, Korea).<br>|

What is the study measuring?
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Primary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Next generation sequencing analysis for microbiota | 16S rRNA pyrosequencing analysis findings of the gastric and duodenal biopsies | up to 6 months | 

Secondary Outcome Measures

| Outcome Measure | Measure Description | Time Frame |
| --- | --- | --- |
| Updated Sydney classification | 0=none, 1=mild, 2= moderate, 3=marked infiltration | up to 6 months | 
| Gastrointestinal endoscopy finding | Upper gastrointestinal endoscopy findings | up to 6 months | 
| Gastrointestinal symptom and food intake score | Scoring system published in Neurogastroenterol Motil 2016;28:1401-1408 | up to 6 months | 

 Terms related to the study
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Keywords Provided by Centre Hospitalier Valida
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Helicobacter pylori, Dyspepsia