1
|
Immunohistochemical Differentiation between Western and East Asian Types of CagA-Positive Helicobacter pylori in Gastric Biopsy Samples. Can J Gastroenterol Hepatol 2022; 2022:1371089. [PMID: 36419567 PMCID: PMC9678484 DOI: 10.1155/2022/1371089] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/24/2022] [Revised: 10/09/2022] [Accepted: 10/13/2022] [Indexed: 11/13/2022] Open
Abstract
BACKGROUND Cag A-positive Helicobacter pylori isolated from human gastric mucosa is categorized as a Western or East Asian allele-type based on whether the cagA gene encodes an EPIYA-C or EPIYA-D motif. We aimed to differentiate between the 2 types of H. pylori by immunohistochemistry (IHC) using formalin-fixed paraffin-embedded (FFPE) gastric biopsy samples. MATERIALS AND METHODS We developed 2 monoclonal antibodies (mAbs) that detect either the EPIYA-C or EPIYA-D motif of the H. pylori CagA protein by IHC using FFPE tissues. FFPE tissue sections from 30 Japanese and 39 Brazilian gastric biopsy samples with H. pylori infection confirmed by Giemsa staining (moderate/severe in the Sydney classification system) were examined by IHC with the novel mAbs followed by polymerase chain reaction (PCR) for EPIYA-C or EPIYA-D using DNA extracted from adjacent tissue sections. RESULTS Differentiation among Western and East Asian types and CagA-negative H. pylori was successful in most (97%) samples by IHC with the novel mAbs and commercially available mAbs that react with a species-specific lipopolysaccharide or a common CagA motif of H. pylori. The detection status of EPIYA-C/D motifs by IHC with the novel mAbs was consistent with the PCR results in 61 (88%) of 69 samples: EPIYA-C(+)/D(-) in zero Japanese and 26 Brazilian samples, EPIYA-C(-)/D(+) in 26 Japanese and 1 Brazilian sample, and EPIYA-C(-)/D(-) in 1 Japanese and 7 Brazilian samples. The detection sensitivity and specificity of IHC with each novel mAb compared with the PCR results were, respectively, 84% and 97% for EPIYA-C, and 97% and 95% for EPIYA-D. CONCLUSIONS The novel mAbs specific to each EPIYA-C or EPIYA-D motif differentiated between Western and East Asian types of CagA-positive H. pylori by IHC using FFPE tissues. Applying these novel mAbs to large numbers of archived pathology samples will contribute to elucidating the association of these allele types with gastric cancer.
Collapse
|
2
|
Bai D, Liu K, Wang R, Zhang WH, Chen XZ, Hu JK. Prevalence Difference of Helicobacter pylori Infection Between Tibetan and Han Ethnics in China: A Meta-analysis on Epidemiologic Studies (SIGES). Asia Pac J Public Health 2022; 35:103-111. [PMID: 36321513 DOI: 10.1177/10105395221134651] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Abstract
China is a multi-ethnic country, and the prevalence of Helicobacter pylori ( H pylori) infection may be diverse among ethnics. This meta-analysis was conducted to compare the prevalence of H pylori infection between Tibetans and Han ethnics. Ten studies that reported the prevalence of H pylori infection between Tibetans and Hans in China were eligible. The pooled prevalence of H pylori infection was 62.2% versus 55.3% among Tibetans and Hans, respectively. Tibetans had a higher risk of H pylori infection than Hans (odds ratio [OR] = 1.38, 95% confidence interval [CI] [1.05, 1.80]). In subgroup analysis, Tibetans with upper gastrointestinal symptoms (OR = 1.51, 95% CI [1.06-2.16]), inhabiting in Tibet (OR = 1.51, 95% CI [1.22, 1.87]), or inhabiting in Northwestern region (OR = 1.15, 95% CI [1.00, 1.31]) had significantly higher risks of H pylori infection. In addition, in the recent 10 years, Hans showed a decreased risk of H pylori infection (OR = 1.81, 95% CI [1.42, 2.30]). Heterogeneity was common, while sensitivity analyses showed partially inconsistent results against main findings. This study demonstrated higher prevalence of H pylori infection in Tibetans compared with Hans, especially in recent years, or in Tibet and northwest China, as well as symptomatic Tibetans. The results suggest tailored strategy and robustness need to be further considered for H pylori screening and eradication among Tibetans.
Collapse
Affiliation(s)
- Dan Bai
- Gastric Cancer Center and Laboratory of Gastric Cancer, West China Hospital, Sichuan University, Chengdu, China
| | - Kai Liu
- Gastric Cancer Center and Laboratory of Gastric Cancer, West China Hospital, Sichuan University, Chengdu, China
| | - Rui Wang
- Department of Gastroenterology, Nursing Section, West China Hospital, Sichuan University, Chengdu, China
| | - Wei-Han Zhang
- Gastric Cancer Center and Laboratory of Gastric Cancer, West China Hospital, Sichuan University, Chengdu, China
| | - Xin-Zu Chen
- Gastric Cancer Center and Laboratory of Gastric Cancer, West China Hospital, Sichuan University, Chengdu, China
- Department of Gastrointestinal and Hernia Surgery, Second People’s Hospital of Yibin, West China Yibin Hospital, Yibin, China
| | - Jian-Kun Hu
- Gastric Cancer Center and Laboratory of Gastric Cancer, West China Hospital, Sichuan University, Chengdu, China
| |
Collapse
|
3
|
Prevalence of Virulence Genes and Antigen Pattern in Helicobacter pylori-Infected Patients and The Level of Some Inflammatory Cytokines Compared with Non-infected Individuals. Jundishapur J Microbiol 2022. [DOI: 10.5812/jjm-121144] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Background: The worldwide prevalence of Helicobacter pylori is about 50%. This bacterium needs a number of virulence factors for pathogenesis. Objectives: This study aimed to determine the prevalence of virulence genes (ureB, cytotoxin-associated gene A [cagA], and vacuolating cytotoxin [vacA]), as well as the antigenic profile in H. pylori strains. Methods: Eighty-five patients with abdominal pain, including 46 H. pylori-positive and 39 H. pylori-negative cases, were enrolled in this study. The serum levels of interleukin (IL)-17F, tumor necrosis factor α (TNF-α), and interferon γ (IFN-γ) cytokines were measured by multiplex kits and flow cytometry. After molecular identification by the ureC gene, vacA, cagA, and ureB genes were detected by polymerase chain reaction (PCR). Finally, after antigenic extraction, the whole-cell protein was exhibited by sodium dodecyl sulphate–polyacrylamide gel electrophoresis (SDS-PAGE). Results: The prevalence of vacA, ureB, and cagA genes were 91.3%, 67.39%, and 50%, respectively. The frequency of genes and cell surface antigens were not significantly different based on the gastritis severity (P > 0.05). IL-17F significantly (P = 0.046) increased in the presence of 19.5 kDa (outer membrane protein [OMP]). Moreover, the OMP antigen significantly enhanced immunoglobulin A (IgA; P = 0.013). In the presence of the 66-kDa (ureB) antigen, the serum level of IFN-γ increased (p = 0.041). Finally, the CagA protein led to increased IgG antibody levels (p = 0.027). Conclusions: Early detection of H. pylori infection can play a crucial role in managing it. Our results suggest that IL-17F, TNF-α, and IFN-γ cytokines could be diagnostic markers. However, further studies are required to fully investigate this suggestion.
Collapse
|
4
|
The validation of the Helicobacter pylori CagA typing by immunohistochemistry: nationwide application in Indonesia. Acta Histochem 2020; 122:151594. [PMID: 32778248 DOI: 10.1016/j.acthis.2020.151594] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 06/25/2020] [Accepted: 07/03/2020] [Indexed: 02/08/2023]
Abstract
We aimed to validate 2 types of antibodies, anti-CagA antibody and anti-East Asian CagA specific antibody (α-EAS antibody) for the determination of CagA status in Indonesia. We also confirmed the performance of α-EAS antibody for the detection of East Asian-type CagA H. pylori. Immunohistochemistry was performed using anti-CagA antibody and α-EAS antibody on gastric biopsy specimens from a total of 967 Indonesian patients. Diagnostic values of immunohistochemistry were evaluated with PCR-based sequencing as gold standard. Anti-CagA antibody had high sensitivity, specificity, and accuracy (87.0 %, 100 %, and 98.8 %, respectively) for determining CagA status. The α-EAS antibody was not suitable for the purpose of CagA status determination, as it had a low sensitivity (23.9 %). High specificity (97.6 %) but low sensitivity (41.2 %) and accuracy (66.3 %) was observed in α-EAS antibody to detect East Asian-type CagA. Patients with positive result of immunohistochemistry using anti-CagA antibody had significantly higher monocyte infiltration score in antrum (P < 0.001) and corpus (P = 0.009). In conclusion, the anti-CagA antibody is still suitable to be used in Indonesia for determining the CagA status, whilst the α-EAS antibody was not appropriate to discriminate between East Asian-type and non-East Asian-type CagA in Indonesia.
Collapse
|
5
|
Bakhti SZ, Latifi-Navid S, Safaralizadeh R. Helicobacter pylori-related risk predictors of gastric cancer: The latest models, challenges, and future prospects. Cancer Med 2020; 9:4808-4822. [PMID: 32363738 PMCID: PMC7333836 DOI: 10.1002/cam4.3068] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2019] [Revised: 03/31/2020] [Accepted: 03/31/2020] [Indexed: 12/24/2022] Open
Abstract
Helicobacter pylori is known as an important determinant of preneoplastic lesions or gastric cancer (GC) risk. The bacterial genotypes may determine the clinical outcomes. However, the evidence for these associations has varied between and within continents, and the actual effect of each gene and corresponding allelic variants are still debatable. In recent years, two new models have been proposed to predict the risk of GC; the phylogeographic origin of H. pylori strains and a disrupted co-evolution between H. pylori and its human host, which potentially explain the geographic differences in the risk of H. pylori-related cancer. However, these models and earlier ones based on putative virulence factors of the bacterium may not fully justify differences in the incidence of GC, reflecting that new theories should be developed and examined. Notably, the new findings also support the role of ancestry-specific germline alteration in contributing to the ethnic/population differences in cancer risk. Moreover the high and low incidence areas of GC have shown differences in transmission ecology, largely affecting the composition of H. pylori populations. As a new hypothesis, it is proposed that any high-risk population may have its own specific risk loci (or variants) as well as new H. pylori strains with national/maybe regional gene pools that should be considered. The latter is seen in the Americas where the rapid evolution of distinct H. pylori subpopulations has been occurred. It is therefore proposed that the deep sequencing of both H. pylori and its human host is simultaneously performed in GC patients and age-sex-matched controls from high-risk areas. The expression and functional activities of the identified new determinants of GC must then be assessed and matched with human and pathogen ancestry, because some of risk loci are ancestry-specific. In addition, potential study-level covariates and moderator variables (eg physical conditions, life styles, gastric microbiome, etc) linked to causal relationships, and their impact, should be recognized and controlled.
Collapse
Affiliation(s)
- Seyedeh Zahra Bakhti
- Department of Biology, Faculty of Sciences, University of Mohaghegh Ardabili, Ardabil, Iran
| | - Saeid Latifi-Navid
- Department of Biology, Faculty of Sciences, University of Mohaghegh Ardabili, Ardabil, Iran
| | - Reza Safaralizadeh
- Department of Animal Biology, Faculty of Natural Sciences, University of Tabriz, Tabriz, Iran
| |
Collapse
|
6
|
Bai D, Wang AM, Liu K, Duan SY, Zhang WH, Hu JK, Chen XZ. Prevalence difference of Helicobacter pylori infection between Tibetan and Han ethnics: The protocol of a meta-analysis on epidemiologic studies. Medicine (Baltimore) 2019; 98:e18566. [PMID: 31876759 PMCID: PMC6946435 DOI: 10.1097/md.0000000000018566] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/28/2019] [Accepted: 12/03/2019] [Indexed: 02/05/2023] Open
Abstract
OBJECTIVES Helicobacter pylori (Hp) is an identified carcinogenic pathogen of human gastric cancer. China is not only one of the countries with high incidence and mortality of gastric cancer, but also a high infection area of Hp. As a multi-ethnic country, China may have a diverse prevalence of Hp infection among ethnics. This meta-analysis tends to compare the prevalence of Hp infection between Tibetan and Han ethnics, the results may provide evidence for targeted screening and eradication of Hp in China. METHODS The following databases will be searched: PubMed, Web of Science, Technology Periodical Database (VIP), China National Knowledge infrastructure (CNKI), and WanFang databases. Studies which reported the prevalence of Hp infection between Tibetans and Hans in China are eligible. Two reviewers will independently screen studies, extract data and assess the risk of bias of included studies. The prevalence of Hp infection between Tibetan and Han ethnics will be compared by meta-analysis. Heterogeneity tests and meta-analyses will be conducted using RevMan 5.3 and Stata 12.0 softwares. Meanwhile, subgroup analysis, publication bias and sensitivity analysis evaluation will be performed where applicable. RESULTS This study will be reported in compliance with the PRISMA statement.This systematic review will not be submitted for any ethical approval since no privacy health information will be included. The findings will be published through peer-reviewed publications or conference presentations. PROSPERO REGISTRATION NUMBER CRD42019121192. CONCLUSIONS Our study will provide us evidence for tailored strategy and robustness of Hp screening and eradication among Tibetans.
Collapse
Affiliation(s)
- Dan Bai
- Department of Gastrointestinal Surgery & Laboratory of Gastric Cancer, West China Hospital, Sichuan University, Chengdu
| | - An-Mo Wang
- Faculty of Clinical Medicine, West China Medical School, Sichuan University, Chengdu
| | - Kai Liu
- Department of Gastrointestinal Surgery & Laboratory of Gastric Cancer, West China Hospital, Sichuan University, Chengdu
| | - Si-Yu Duan
- Faculty of Clinical Medicine, West China Medical School, Sichuan University, Chengdu
| | - Wei-Han Zhang
- Department of Gastrointestinal Surgery & Laboratory of Gastric Cancer, West China Hospital, Sichuan University, Chengdu
| | - Jian-Kun Hu
- Department of Gastrointestinal Surgery & Laboratory of Gastric Cancer, West China Hospital, Sichuan University, Chengdu
| | - Xin-Zu Chen
- Department of Gastrointestinal Surgery & Laboratory of Gastric Cancer, West China Hospital, Sichuan University, Chengdu
- Department of Gastrointestinal and Hernia Surgery, West China Yibin Hospital, Sichuan University, Yibin
- Department of General Surgery, West China Longquan Hospital, Sichuan University, Chengdu, China
| |
Collapse
|
7
|
Doohan D, Miftahussurur M, Matsuo Y, Kido Y, Akada J, Matsuhisa T, Yee TT, Htet K, Aftab H, Vilaichone RK, Mahachai V, Ratanachu-Ek T, Tshering L, Waskito LA, Fauzia KA, Uchida T, Syam AF, Rezkitha YAA, Yamaoka Y. Characterization of a novel Helicobacter pylori East Asian-type CagA ELISA for detecting patients infected with various cagA genotypes. Med Microbiol Immunol 2019; 209:29-40. [PMID: 31549252 DOI: 10.1007/s00430-019-00634-5] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.6] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/29/2019] [Accepted: 09/06/2019] [Indexed: 12/17/2022]
Abstract
Currently, Western-type CagA is used in most commercial Helicobacter pylori CagA ELISA kits for CagA detection rather than East Asian-type CagA. We evaluated the ability of the East Asian-type CagA ELISA developed by our group to detect anti-CagA antibody in patients infected with different cagA genotypes of H. pylori from four different countries in South Asia and Southeast Asia. The recombinant CagA protein was expressed and later purified using GST-tag affinity chromatography. The East Asian-type CagA-immobilized ELISA was used to measure the levels of anti-CagA antibody in 750 serum samples from Bhutan, Indonesia, Myanmar, and Bangladesh. The cutoff value of the serum antibody in each country was determined via Receiver-Operating Characteristic (ROC) analysis. The cutoff values were different among the four countries studied (Bhutan, 18.16 U/mL; Indonesia, 6.01 U/mL; Myanmar, 10.57 U/mL; and Bangladesh, 6.19 U/mL). Our ELISA had better sensitivity, specificity, and accuracy of anti-CagA antibody detection in subjects predominantly infected with East Asian-type CagA H. pylori (Bhutan and Indonesia) than in those infected with Western-type CagA H. pylori predominant (Myanmar and Bangladesh). We found positive correlations between the anti-CagA antibody and antral monocyte infiltration in subjects from all four countries. There was no significant association between bacterial density and the anti-CagA antibody in the antrum or the corpus. The East Asian-type CagA ELISA had improved detection of the anti-CagA antibody in subjects infected with East Asian-type CagA H. pylori. The East Asian-type CagA ELISA should, therefore, be used in populations predominantly infected with East Asian-type CagA.
Collapse
Affiliation(s)
- Dalla Doohan
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Yufu, 879-5593, Japan.,Institute of Tropical Disease, Universitas Airlangga, Surabaya, 60115, Indonesia
| | - Muhammad Miftahussurur
- Institute of Tropical Disease, Universitas Airlangga, Surabaya, 60115, Indonesia.,Gastroentero-Hepatology Division, Department of Internal Medicine, Faculty of Medicine-Dr. Soetomo Teaching Hospital, Universitas Airlangga, Surabaya, 60131, Indonesia
| | - Yuichi Matsuo
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Yufu, 879-5593, Japan.,Department of Host-Defense Biochemistry, Institute of Tropical Medicine (NEKKEN), Nagasaki University, Nagasaki, Japan
| | - Yasutoshi Kido
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Yufu, 879-5593, Japan.,Department of Parasitology, Graduate School of Medicine, Osaka City University, Osaka, Japan
| | - Junko Akada
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Yufu, 879-5593, Japan
| | - Takeshi Matsuhisa
- Department of Gastroenterology, Tama-Nagayama University Hospital of Nippon Medical School, Tama, Japan
| | - Than Than Yee
- Department of GI and HBP Surgery, No (2), Defense Service General Hospital (1000 Bedded), Nay Pyi Taw, Myanmar
| | - Kyaw Htet
- Department of GI and HBP Surgery, No (1), Defense Service General Hospital (1000 Bedded), Mingalodon, Yangon, Myanmar
| | - Hafeza Aftab
- Department of Gastroenterology, Dhaka Medical College and Hospital, Dhaka, Bangladesh
| | - Ratha-Korn Vilaichone
- Gastroenterology Unit, Department of Medicine, Thammasat University Hospital, Pathum Thani, Thailand
| | - Varocha Mahachai
- GI and Liver Center, Bangkok Medical Center, Bangkok, 10310, Thailand
| | | | - Lotay Tshering
- Department of Surgery, Jigme Dorji Wangchuck National Referral Hospital, Thimphu, 11001, Bhutan
| | - Langgeng Agung Waskito
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Yufu, 879-5593, Japan.,Institute of Tropical Disease, Universitas Airlangga, Surabaya, 60115, Indonesia
| | - Kartika Afrida Fauzia
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Yufu, 879-5593, Japan.,Institute of Tropical Disease, Universitas Airlangga, Surabaya, 60115, Indonesia
| | - Tomohisa Uchida
- Department of Molecular Pathology, Oita University Faculty of Medicine, Yufu, 879-5593, Japan
| | - Ari Fahrial Syam
- Division of Gastroenterology, Department of Internal Medicine, Faculty of Medicine, University of Indonesia, Jakarta, Indonesia
| | - Yudith Annisa Ayu Rezkitha
- Institute of Tropical Disease, Universitas Airlangga, Surabaya, 60115, Indonesia.,Faculty of Medicine, University of Muhammadiyah Surabaya, Surabaya, 60113, Indonesia
| | - Yoshio Yamaoka
- Department of Environmental and Preventive Medicine, Oita University Faculty of Medicine, Yufu, 879-5593, Japan. .,Gastroentero-Hepatology Division, Department of Internal Medicine, Faculty of Medicine-Dr. Soetomo Teaching Hospital, Universitas Airlangga, Surabaya, 60131, Indonesia. .,Department of Gastroenterology and Hepatology, Baylor College of Medicine and Michael E. DeBakey Veterans Affairs Medical Center, Houston, TX, 77030, USA.
| |
Collapse
|
8
|
The Story of Helicobacter pylori: Depicting Human Migrations from the Phylogeography. ADVANCES IN EXPERIMENTAL MEDICINE AND BIOLOGY 2019; 1149:1-16. [PMID: 31016625 DOI: 10.1007/5584_2019_356] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/06/2023]
Abstract
Helicobacter pylori is a spiral-shaped Gram-negative bacterium, which has infected more than half of the human population. Besides its colonisation capability, the genetic diversity of H. pylori is exceptionally well structured and belongs to several distinct genetic populations, depicting various prehistorical human migration events. The evolutionary relationship of H. pylori with its host had been started at least ~100,000 years ago. In addition, the discovery of the ancient H. pylori genome from a European Copper Age glacier mummy, "The Iceman", gave the idea that the second out of Africa migration resulted in the recombinant population of hpEurope at least about 5300 years ago. The advancement of next-generation genome sequencing discovered the prophage of H. pylori and could discriminate the big population of hpEurope into two different subpopulations. In addition, the implementation of the chromopainter/fineSTRUCTURE algorithm to the whole genome analysis of H. pylori provides a finer resolution population genetics of H. pylori; therefore it could also depict the recent migrations within the past 500 years after colonial expansion. This discovery shows that the genetic recombination of H. pylori strains is far more dynamic compared to its human host, but still maintains the similarity to its host, suggesting that H. pylori is a handy tool to reconstruct the human migration both in the past and the recent.
Collapse
|
9
|
Abstract
This review provides the most recent data concerning the epidemiology of Helicobacter pylori infection. Overall, the trend of declining prevalence of H. pylori infection is continuing, with major evidence available from studies in Europe. However, in some parts of the world, for example, in some countries in the Middle East, the prevalence has remained relatively stable. A number of systematic reviews and meta-analyses have been published during the past year indicating the lowest prevalence rates of the infection in Oceania (24.4%), the highest in Africa (79.1%), and the global annual recurrence rate of H. pylori (4.3%). The recurrence rates were found to be directly related to the human development index and prevalence of infection. Several studies have addressed the correlation between H. pylori infection and sociodemographic conditions, source of drinking water and dietary factors. A hypothesis on the role of insects and yeasts in transmitting H. pylori has been suggested and addressed. Helicobacter sp. have been found in flow flies in Brazil. So far there is no evidence available that H. pylori may survive and persist on the outer body of the fly.
Collapse
Affiliation(s)
- Olga Sjomina
- Institute of Clinical and Preventive Medicine, Faculty of Medicine, University of Latvia, Riga, Latvia.,Riga East University Hospital, Riga, Latvia
| | - Jelizaveta Pavlova
- Institute of Clinical and Preventive Medicine, Faculty of Medicine, University of Latvia, Riga, Latvia
| | - Yaron Niv
- Department of Gastroenterology, Rabin Medical Center, Tel Aviv University, Tel Aviv, Israel
| | - Marcis Leja
- Institute of Clinical and Preventive Medicine, Faculty of Medicine, University of Latvia, Riga, Latvia.,Riga East University Hospital, Riga, Latvia.,Digestive Diseases Centre GASTRO, Riga, Latvia
| |
Collapse
|