Helicobacter pylori and gastric cancer: Indian enigma

Current paradigms in the management of refractory Helicobacter pylori infection

Helicobacter pylori is the most prevalent chronic bacterial infection, with approximately half of the world's population estimated to be colonized. The World Health Organization (WHO) has classified Helicobacter pylori as a class-I carcinogen. All main society guidelines recommend its eradication in infected individuals. The global trend indicates that eradication rates are decreasing annually and the likelihood of eradication decreases with each unsuccessful therapeutic attempt. Resistance to antibiotics in H. pylori strains is the leading cause for eradication failure. Still, drug resistance and treatment failure may be complex, multi-dimensional and associated with several other factors. Knowledge of these factors can aid in optimizing eradication rates. This review will focus on the factors associated with refractory H. pylori, with a particular emphasis on antibiotic resistance mechanisms and their clinical implications. Also, the most recent literature and recommendations available for determining an appropriate regimen after the failure of the first attempt at eradication will be discussed.

Estimation of gastric cancer burden attributable to Helicobacter pylori infection in Asia

BACKGROUND

Helicobacter pylori causes large burden of gastric cancer (GC) in Asia. We aimed to comprehensively quantify the burden of GC attributable to H. pylori infection in Asia.

METHODS

We searched related articles from January 1998 to December 2020 to obtain the prevalence and relative risks (or odds ratio) of GC associated with H. pylori in Asia. The burden of GC attributable to H. pylori infection was quantified by Population Attributable Fraction (PAF) and Disability-adjusted life-years (DALYs).

RESULTS

We quantified the burden of GC attributable to H. pylori infection with 415.6 thousand DALYs and 38.03% PAF through the five included Asian countries in 2019. The study found that the burden had obvious regional differences. The DALYs ranged from 298.9 thousand in China to 1.9 thousand in Malaysia, and the PAFs were between 58.00% in Japan and 30.89% in China. The average prevalence of H. pylori in the included general population was estimated to be 56.29%.

CONCLUSIONS

Helicobacter pylori poses a huge disease burden of GC to the population, and its eradication should receive attention, especially in the countries with high incidence of and mortality due to GC.

Region-specific genomic signatures of multidrug-resistant Helicobacter pylori isolated from East and South India

Helicobacter pylori is a ubiquitous bacterium and contributes significantly to the burden of chronic gastritis, peptic ulcers, and gastric cancer across the world. Adaptive phenotypes and virulence factors in H. pylori are heterogeneous and dynamic. However, limited information is available about the molecular nature of antimicrobial resistance phenotypes and virulence factors of H. pylori strains circulating in India. In the present study, we analyzed the whole genome sequences of 143 H. pylori strains, of which 32 are isolated from two different regions (eastern and southern) of India. Genomic repertoires of individual strains show distinct region-specific signatures. We observed lower resistance phenotypes and genotypes in the East Indian (Kolkata) H. pylori isolates against amoxicillin and furazolidone antibiotics, whereas higher resistance phenotypes to metronidazole and clarithromycin. Also, at molecular level, a greater number of AMR genes were observed in the east Indian H. pylori isolates as compared to the southern Indian isolates. From our findings, we suggest that metronidazole and clarithromycin antibiotics should be used judicially in the eastern India. However, no horizontally acquired antimicrobial resistance gene was observed in the current H. pylori strains. The comparative genome analysis shows that the number of genes involved in virulence, disease and resistance of H. pylori isolated from two different regions of India is significantly different. Single-nucleotide polymorphisms (SNPs) based phylogenetic analysis distinguished H. pylori strains into different clades according to their geographical locations. Conditionally beneficial functions including antibiotic resistance phenotypes that are linked with faster evolution rates in the Indian isolates.

“Helicobacter pylori treatment guideline: An Indian perspective”: Letter to the editor

Treatment guidelines in many countries for Helicobacter pylori (H. pylori) may differ. Owing to the various characteristics of bacteria, clinical manifestations, resistance to antibiotics and recurrence rate, treatment regimens may change. In this letter, we would like to give an Indian perspective on H. pylori treatment guidelines.

Management of Helicobacter pylori infection: the Maastricht VI/Florence consensus report

Helicobacter pyloriInfection is formally recognised as an infectious disease, an entity that is now included in the International Classification of Diseases 11th Revision. This in principle leads to the recommendation that all infected patients should receive treatment. In the context of the wide clinical spectrum associated with Helicobacter pylori gastritis, specific issues persist and require regular updates for optimised management.The identification of distinct clinical scenarios, proper testing and adoption of effective strategies for prevention of gastric cancer and other complications are addressed. H. pylori treatment is challenged by the continuously rising antibiotic resistance and demands for susceptibility testing with consideration of novel molecular technologies and careful selection of first line and rescue therapies. The role of H. pylori and antibiotic therapies and their impact on the gut microbiota are also considered.Progress made in the management of H. pylori infection is covered in the present sixth edition of the Maastricht/Florence 2021 Consensus Report, key aspects related to the clinical role of H. pylori infection were re-evaluated and updated. Forty-one experts from 29 countries representing a global community, examined the new data related to H. pylori infection in five working groups: (1) indications/associations, (2) diagnosis, (3) treatment, (4) prevention/gastric cancer and (5) H. pylori and the gut microbiota. The results of the individual working groups were presented for a final consensus voting that included all participants. Recommendations are provided on the basis of the best available evidence and relevance to the management of H. pylori infection in various clinical fields.

Gastrointestinal microbiome and Helicobacter pylori: Eradicate, leave it as it is, or take a personalized benefit–risk approach?

Helicobacter pylori (H. pylori) is generally regarded as a human pathogen and a class 1 carcinogen, etiologically related to gastric and duodenal ulcers, gastric cancer, and mucosa-associated lymphoid tissue lymphoma. However, H. pylori can also be regarded as a commensal symbiont. Unlike other pathogenic/ opportunistic bacteria, H. pylori colonization in infancy is facilitated by T helper type 2 immunity and leads to the development of immune tolerance. Fucosylated gastric mucin glycans, which are an important part of the innate and adaptive immune system, mediate the adhesion of H. pylori to the surface of the gastric epithelium, contributing to successful colonization. H. pylori may have beneficial effects on the host by regulating gastrointestinal (GI) microbiota and protecting against some allergic and autoimmune disorders and inflammatory bowel disease. The potential protective role against inflammatory bowel disease may be related to both modulation of the gut microbiota and the immunomodulatory properties of H. pylori. The inverse association between H. pylori and some potentially proinflammatory and/or procarcinogenic bacteria may suggest it regulates the GI microbiota. Eradication of H. pylori can cause various adverse effects and alter the GI microbiota, leading to short-term or long-term dysbiosis. Overall, studies have shown that gastric Actinobacteria decrease after H. pylori eradication, Proteobacteria increase during short-term follow-up and then return to baseline levels, and Enterobacteriaceae and Enterococcus increase in the short-term and interim follow-up. Various gastric mucosal bacteria (Actinomyces, Granulicatella, Parvimonas, Peptostreptococcus, Prevotella, Rothia, Streptococcus, Rhodococcus, and Lactobacillus) may contribute to precancerous gastric lesions and cancer itself after H. pylori eradication. H. pylori eradication can also lead to dysbiosis of the gut microbiota, with increased Proteobacteria and decreased Bacteroidetes and Actinobacteria. The increase in gut Proteobacteria may contribute to adverse effects during and after eradication. The decrease in Actinobacteria, which are pivotal in the maintenance of gut homeostasis, can persist for > 6 mo after H. pylori eradication. Furthermore, H. pylori eradication can alter the metabolism of gastric and intestinal bacteria. Given the available data, eradication cannot be an unconditional recommendation in every case of H. pylori infection, and the decision to eradicate H. pylori should be based on an assessment of the benefit–risk ratio for the individual patient. Thus, the current guidelines based on the unconditional “test-and-treat” strategy should be revised. The most cautious and careful approach should be taken in elderly patients with multiple eradication failures since repeated eradication can cause antibiotic-associated diarrhea, including severe Clostridioides difficile-associated diarrhea and colitis and antibiotic-associated hemorrhagic colitis due to Klebsiella oxytoca. Furthermore, since eradication therapy with antibiotics and proton pump inhibitors can lead to serious adverse effects and/or dysbiosis of the GI microbiota, supplementation of probiotics, prebiotics, and microbial metabolites (e.g., butyrate + inulin) should be considered to decrease the negative effects of eradication.

Clinical Effect of Clarithromycin Combined with Tinidazole on Helicobacter pylori-Related Gastritis and Its Influence on COX-2 Expression

Studies have shown that COX-2 expression is upregulated in gastric cancer (GC) as well as in precancerous lesions and in Helicobacter pylori-induced inflammation, suggesting that cyclooxygenase-2 (COX-2) may play an important role in gastric carcinogenesis. We attempted to investigate the role of clarithromycin with tinidazole on Helicobacter pylori-related gastritis from the aspects of clinical effect and COX-2 expression. From January 2016 to January 2019, 130 patients with Helicobacter pylori-related chronic gastritis were collected and grouped into the observation group (OG) and the control group (CG). Altogether, 80 patients in the OG were treated with clarithromycin with tinidazole, while 50 patients in the CG were treated with amoxicillin with metronidazole. Clinical symptom improvement time, content of COX-2 and B cell lymphoma-2 (BCL-2), content of inflammatory factors interleukin-1 (IL-1), IL-4, and C-reactive protein (CRP), expression level of nutritional indicators serum albumin (ALB), realbumin (PA), and transferrin (TF), clearance of Helicobacter pylori, total effective rate, and incidence of adverse reactions were detected. Compared with the CG, the OG had shorter clinical symptom improvement time, lower COX-2 and Bcl-2, lower expression of inflammatory factors IL-1, IL-4, and CRP, higher expression of nutritional indicators ALB, TF, and PA, higher clearance rate of Helicobacter pylori, higher total effective rate, and lower incidence of adverse reactions. Clarithromycin combined with tinidazole can effectively improve the clinical effect of Helicobacter pylori-related gastritis and reduce the expression level of COX-2.

Antimicrobial resistance and virulence in Helicobacter pylori: Genomic insights

Microbes evolve rapidly by modifying their genome through mutations or acquisition of genetic elements. Antimicrobial resistance in Helicobacter pylori is increasingly prevalent in India. However, limited information is available about the genome of resistant H. pylori isolated from India. Our pan- and core-genome based analyses of 54 Indian H. pylori strains revealed plasticity of its genome. H. pylori is highly heterogenous both in terms of the genomic content and DNA sequence homology of ARGs and virulence factors. We observed that the H. pylori strains are clustered according to their geographical locations. The presence of point mutations in the ARGs and absence of acquired genetic elements linked with ARGs suggest target modifications are the primary mechanism of its antibiotic resistance. The findings of the present study would help in better understanding the emergence of drug-resistant H. pylori and controlling gastric disorders by advancing clinical guidance on selected treatment regimens.

Gastric cancer: lessons learned from high-incidence geographic regions

Gastric cancer is a global health concern. There is a marked geographical variability in the incidence of gastric cancer, with higher incidence in East and Central Asia followed by Latin America and Eastern Europe. Survival rates in gastric cancer are low and strongly stage dependent. Due to the limited survival benefit achieved from currently available therapeutic options, prevention and early diagnosis are essential to minimize morbidity and mortality from this disease. Countries with high incidence of gastric cancer have pioneered the development and implementation of prevention and screening programs. Helicobacter pylori (H. pylori) eradication and dietary modifications are the main preventive strategies. Upper gastrointestinal (UGI) endoscopy is the mainstay screening strategy for early diagnosis. In this article, we review the lessons learned for gastric cancer diagnosis and treatment from high-incidence areas and discuss their applicability for treatment in the Western world to reduce morbidity and mortality from this disease.

Management of Helicobacter pylori infection: The Bhubaneswar Consensus Report of the Indian Society of Gastroenterology

The Indian Society of Gastroenterology (ISG) felt the need to organize a consensus on Helicobacter pylori (H. pylori) infection and to update the current management of H. pylori infection; hence, ISG constituted the ISG's Task Force on Helicobacter pylori. The Task Force on H. pylori undertook an exercise to produce consensus statements on H. pylori infection. Twenty-five experts from different parts of India, including gastroenterologists, pathologists, surgeons, epidemiologists, pediatricians, and microbiologists participated in the meeting. The participants were allocated to one of following sections for the meeting: Epidemiology of H. pylori infection in India and H. pylori associated conditions; diagnosis; treatment and retreatment; H. pylori and gastric cancer, and H. pylori prevention/public health. Each group reviewed all published literature on H. pylori infection with special reference to the Indian scenario and prepared appropriate statements on different aspects for voting and consensus development. This consensus, which was produced through a modified Delphi process including two rounds of face-to-face meetings, reflects our current understanding and recommendations for the diagnosis and management of H. pylori infection. These consensus should serve as a reference for not only guiding treatment of H. pylori infection but also to guide future research on the subject.

Cancer scenario in North-East India & need for an appropriate research agenda

Background & objectives

The North-Eastern (NE) region has the highest incidence of cancer in India, and is also burdened by higher prevalence of risk factors and inadequate cancer treatment facilities. The aim of this study was to describe the cancer profile of the NE region, focussing on the cancer sites that have high incidence and to identify research priorities.

Methods

Incidence data from population-based cancer registries (PBCRs) in the North-East region (8 States) were utilized and relevant literature was reviewed to identify risk factors.

Results

Aizawl district in Mizoram had the highest incidence of cancer in men [age-adjusted rate (AAR) of 269.4 per 100,000]. Among women, Papumpare district of Arunachal Pradesh had the highest incidence (AAR of 219.8) in India. East Khasi Hills district in Meghalaya had the highest incidence of oesophageal cancer (AAR of 75.4 in men and 33.6 in women). Aizawl district in Mizoram had the highest incidence of stomach (AAR-44.2 in men) and Papumpare district had highest incidence of stomach (AAR 27.1 in women), liver (AAR- 35.2 in men and 14.4 in women) and cervical cancers (AAR- 27.7). Lung cancer (AAR- 38.8 in men and 37.9 in women) and gall bladder cancer incidence (AAR- 7.9 in men and 16.2 in women) were highest in Aizawl and Assam (Kamrup urban) PBCRs, respectively. Nagaland had the highest incidence of nasopharyngeal cancer (AAR of 14.4 in men and 6.5 in women), a relatively rare cancer in other regions of India. Four States (Arunachal Pradesh, Manipur, Sikkim and Tripura) in NE had only one cancer treating facility.

Interpretation & conclusions

Further research on specific aetiological factors in the region and multi-disciplinary research for development of tools, techniques and guidelines for cancer control are the need of the hour.

Profile of Helicobacter pylori cagA &vacA genotypes and its association with the spectrum of gastroduodenal disease

PURPOSE

Globally, H. pylori virulence factors cagA and vacA genotypes and its variation is leading to the austere form of the gastroduodenal disease. Our objectives were to detect H. pylori in dyspeptic patients from biopsy samples with the validation of the various existing diagnostic tools and to screen the cagA, vacA genotypes profile from biopsy specimens and how it impacts in progression of gastroduodenal disease in southern India.

METHODS

374 patients who attended endoscopy unit at Kasturba Hospital, Manipal with their consent obtained their biopsies. H. pylori were detected by HPE, Culture, RUT and PCR and its virulence gene were patterned with PCR.

RESULTS

The positive rate of H. pylori by HPE, RUT, Culture and PCR were 51.33%, 47.1%, 32.4% and 50.3% respectively and comparison by Bayesian LCMs analysis showed PCR is superior among them. The frequency of H. pylori virulence gene viz cagPAI (cagA) were 80.9%, and vacA alleles-s1m1 (42%), s1m2 (33%) and s2m2 (25%) genotypes by PCR respectively. Four combinations of cagA/vacA genotypes were noted, majority of strains harboured cagA⁺/vacA s1m1 genotypes (42.6%), interestingly this hyper-virulent strain more frequently seen in severe gastroduodenal disease whereas cagPAI negative strains as well as cagA^-/vacA s2m2 combinations (19.1%) are seen most commonly in functional dyspepsia cases and depicted significant association by Chi-square test.

CONCLUSIONS

This study validates and compares the existing diagnostic methods for detecting H. pylori in biopsies. Also, it reveals some pattern of virulence gene combination will play a vital role in disease progression.

Elevated Expression of DNA Methyltransferases and Enhancer of Zeste Homolog 2 in Helicobacter pylori - Gastritis and Gastric Carcinoma

AIM

The aim of this study was to study the role of key epigenetic regulators pertaining to DNA methylation and histone-modification systems in Helicobacter pylori (HP)-associated gastritis and gastric carcinogenesis.

METHODS

The expression of DNA methyltransferase (DNMT-1, 3A, and 3B) and the catalytic subunit of polycomb repressive complex-2 (enhancer of zeste homolog 2 [EZH2]) in gastric carcinomas (n = 104), mucosa adjacent to carcinoma (n = 104), HP-associated gastritis (n = 95), and histologically normal mucosa (n = 31) was assessed by immunohistochemistry and qRT-PCR.

RESULTS

The expression of all 3 DNMTs and EZH2 was significantly higher in HP-associated gastritis and carcinoma cases than in those with adjacent and normal mucosa. The expression of DNMT-1 and 3B was maximum in HP-associated gastritis. DNMT-3A showed higher expression in carcinoma-adjacent mucosa than in normal mucosa. Interestingly, the expression of EZH2 was higher in cases of HP-associated gastritis with metaplasia than in those without metaplasia and also in cases of intestinal type of adenocarcinoma. Significant positive correlation of EZH2 was identified with DNMT-1, DNMT-3A, and DNMT-3B. However, none of these markers was associated with survival outcome.

CONCLUSION

This study establishes an important role of the key epigenetic regulators in the pathogenesis of both HP-associated gastritis and gastric carcinoma. Higher expression of all the epigenetic markers in the gastritis and their persistence in the carcinoma point toward their implications in HP-driven gastric carcinogenesis. Further, an inter-relation between the 2 arms of epigenetics, namely, DNA methylation and histone-modification in the pathogenesis of gastric carcinoma, is also documented. Given the reversibility of epigenetic phenomenon, these molecules may be of important therapeutic use.

Predictive Effect of Helicobacter pylori in Gastric Carcinoma Development: Systematic Review and Quantitative Evidence Synthesis

Helicobacter pylori (H. pylori) is a bacterial pathogen implicated in gastritis, gastric ulceration, and gastric carcinoma. This study aimed to synthesize literature in providing evidence on the causative role of H. pylori in gastric carcinoma development. This study is based on assessing public literature using an applied meta-analysis, namely, quantitative evidence synthesis (QES). The analytic procedure uses DerSimonian-Laird, including assessing heterogeneity. The QES also utilizes meta-regression and the environmental effect associated with H. pylori in gastric cancer development. Eighteen studies are included in the QES. There is increased prevalence of H. pylori exposure among the cases. The heterogeneity between the CES and individual effect sizes is also significant. Despite controlling for the confoundings, there is increased exposure to H. pylori among the gastric cancer cases, regardless of the differences in the geographic location. H. pylori in this synthesized literature illustrates the contributory role of this microbe in gastric carcinoma. Additionally, regardless of geographic locale, namely, South Korea or Spain, H. pylori is implicated in gastric cancer development.

Novel virulence factor dupA of Helicobacter pylori as an important risk determinant for disease manifestation: An overview

Helicobacter pylori (H. pylori) is a microaerophilic, Gram-negative, human gastric pathogen found usually in the mucous lining of stomach. It infects more than 50% of the world’s population and leads to gastroduodenal diseases. The outcome of disease depends on mainly three factors: Host genetics, environment and bacterial factors. Among these, bacterial virulence factors such as cagA, vacA are well known for their role in disease outcomes. However, based on the global epidemiological results, none of the bacterial virulence (gene) factors was found to be associated with particular diseases like duodenal ulcer (DU) in all populations. Hence, substantial importance has been provided for research in strain-specific genes outside the cag pathogenicity island, especially genes located within the plasticity regions. dupA found within the plasticity regions was first demonstrated in 2005 and was proposed for duodenal ulcer development and reduced risk of gastric cancer in certain geographical regions. Due to the discrepancies in report from different parts of the world in DU development related to H. pylori virulence factor, dupA became an interesting area of research in elucidating the role of this gene in the disease progression. In this review, we shed light on the detailed information available on the polymorphisms in dupA and their clinical relevance. We have critically appraised several pertinent studies on dupA and discussed their merits and shortcomings. This review also highlights dupA gene as an important biomarker for DU in certain populations.

Using next-generation sequencing to analyze Helicobacter pylori clones with different levofloxacin resistances from a patient with eradication failure

The regimens containing levofloxacin (LVX) have been recommended as an alternate to standard triple therapy to treat Helicobacter pylori infections and H pylori mixed infection always lead to H pylori chronic infection. Although the molecular mechanism of LVX resistance with gyrA gene mutation has been clearly understood in H pylori, other genes involved in antibiotic resistance remain unclear. Efflux pump plays an important role in clinically relevant multidrug resistance. Furthermore, the relationship between the strains with different LVX level-resistances from individuals is also unknown.Helicobacter pylori monoclonal strains were isolated from patients with eradication failure. E test was used to detect the minimal inhibitory concentration of LVX. One lower-level LVX-resistant clone and 2 higher-level LVX-resistant clones from the same patient were selected to sequence the complete genomes. Single-nucleotide variants (SNVs) and mutations were extracted and analyzed from gryA and resistance-nodulation-division family efflux genes.Two clones with higher-level resistance had the mutation pattern of Asn87Lys and one lower-level LVX-resistant clone had an Asp91Asn mutation. Compared to clones with higher-level resistance, the higher genetic variations were found in genes belonging to the resistance-nodulation-division family in H pylori strains with lower-level resistance to LVX. There were significantly more SNVs of Hp0970 (hefE) and Hp1329 (hefI) in the lower-level LVX-resistant clone than those in the higher-level LVX-resistant clones (P = .044).The mutation pattern of the Asn87Lys of the gyrA gene confers a higher resistance to LVX than that of the Asp91Asn in H pylori. Increase in the number of SNVs of the Hp0970 (hefE) and Hp1329 (hefI) genes change the resistance to LVX. Twelve mutations verified by Sanger sequencing in Hp0970 (hefE) and Hp1329 (hefI) may decrease resistant levels to LVX.

Association of tobacco smoke-infused water (tuibur) use by Mizo people and risk of Helicobacter pylori infection

The study aims to understand the influence of environmental and lifestyle factors and more specifically the role of tobacco smoke-infused water (tuibur) on Helicobacter pylori infection. It was a cross-sectional study to measure the epidemiological risk factors associated with H. pylori infection among the tribal population in Northeast India. Endoscopic samples were collected from the antrum region of the stomach from 863 participants with gastritis. H. pylori infection was confirmed in 475 samples by the rapid urease test and PCR-based methods. Information on demographic and lifestyle factors was collected using a validated and standardized questionnaire. Logistic regression was used to estimate odds ratio (OR) and 95% confidence interval (CI) for the association between the various factors and H. pylori. The use of tuibur was associated with an increased OR of H. pylori infection (OR = 3.32, 95% Cl = 1.95-5.83). Tobacco chewers (OR = 1.49, 95% Cl = 1.06-2.09), smokers (OR = 1.81, 95% Cl = 1.26-2.61), and alcohol consumers (OR = 1.81, 95% Cl = 1.19-2.76) were also infected with H. pylori. The results were not attenuated after adjusting for major well-known risk factors of H. pylori infection. The habit of tuibur consumption may be a contributing factor to the high prevalence of H. pylori infection and in turn, may contribute to the high prevalence of gastritis among the Mizo population.

Long noncoding RNA THAP9-AS1 is induced by Helicobacter pylori and promotes cell growth and migration of gastric cancer

Background

Long noncoding RNAs (LncRNAs) have been confirmed to play crucial roles in cancer biology. Gastric cancer (GC) is the third leading cause of cancer related death, and Helicobacter pylori (H. pylori) is the major risk factor for GC. In this study, we focused on the roles of H. pylori-related lncRNAs in the progression of GC.

Method

Differentially expressed lncRNAs were identified through RNA-seq analysis of H. pylori-infected GC cells.

Results

We found that the expression of the lncRNA THAP9-AS1 was up-regulated after infection of GC cells with H. pylori and was higher in GC tissues than in gastritis tissues. Colony formation, CCK8 and transwell assays were executed to show that THAP9-AS1 can promote GC cell proliferation and migration in vitro. Our study identified the pro-oncogenic lncRNA THAP9-AS1, which has a higher expression level in GC tissues than in gastritis tissues and which promoted the proliferation and migration of GC cells in vitro.

Conclusion

These findings may provide a potential therapeutic target for H. pylori-associated GC.

Cost Effectiveness of Gastric Cancer Screening According to Race and Ethnicity

BACKGROUND & AIMS

There are marked racial and ethnic differences in non-cardia gastric cancer prevalence within the United States. Although gastric cancer screening is recommended in some regions of high prevalence, screening is not routinely performed in the United States. Our objective was to determine whether selected non-cardia gastric cancer screening for high-risk races and ethnicities within the United States is cost effective.

METHODS

We developed a decision analytic Markov model with the base case of a 50-year-old person of non-Hispanic white, non-Hispanic black, Hispanic, or Asian race or ethnicity. The cost effectiveness of a no-screening strategy (current standard) for non-cardia gastric cancer was compared with that of 2 endoscopic screening modalities initiated at the time of screening colonoscopy for colorectal cancer: upper esophagogastroduodenoscopy with biopsy examinations and continued surveillance only if intestinal metaplasia or more severe pathology is identified or esophagogastroduodenoscopy with biopsy examinations continued every 2 years even in the absence of identified pathology. We used prevalence rates, transition probabilities, costs, and quality-adjusted life years (QALYs) from publications and public data sources. Outcome measures were reported in incremental cost-effectiveness ratios, with a willingness-to-pay threshold of $100,000/QALY.

RESULTS

Compared with biennial and no screening, screening esophagogastroduodenoscopy with continued surveillance only when indicated was cost effective for non-Hispanic blacks ($80,278/QALY), Hispanics ($76,070/QALY), and Asians ($71,451/QALY), but not for non-Hispanic whites ($122,428/QALY). The model was sensitive to intestinal metaplasia prevalence, transition rates from intestinal metaplasia to dysplasia to local and regional cancer, cost of endoscopy, and cost of resection (endoscopic or surgical).

CONCLUSIONS

Based on a decision analytic Markov model, endoscopic non-cardia gastric cancer screening for high-risk races and ethnicities could be cost effective in the United States.

Non-invasive Diagnostic of Helicobacter pylori in Stools by Nested-qPCR

The aim of this study was to develop a non-invasive diagnostic test for the detection of Helicobacter pylori in stool samples from digestive symptomatic patients, using a new protocol of nested-qPCR. A total of 143 patients were invited to participate in the study. A gastric biopsy of each patient was collected for Rapid Urease Testing (RUT) and histology by Giemsa stain. A fecal sample for nested-qPCR analysis was also obtained. DNA was extracted from the fecal samples, and conventional PCR followed by qPCR of the ureC gene of H. pylori was carried out. We evaluated the presence of H. pylori, in 103 females and 40 males, mean (± SD) age of 56.5 ± 14.18. The sensitivity of RUT to detect the infection was 67.0% (95% C.I.: 57.2 - 75.8) and specificity was 92.3% (95% C.I.: 76.5 - 99.1). Histology by Giemsa stain, commonly used as a reference for H. pylori detection, showed a sensitivity of 98.6% (95% C.I.: 92.5 - 100.0) and a specificity of 89.7% (95% C.I.: 72.7 - 97.8). In contrast, detection of H. pylori infection in stools by nested-qPCR showed a sensitivity of 100% (95% C.I.: 94.9 - 100.0) and a specificity of 83.9% (95% C.I.: 66.3 - 94.6). Our test, based in nested-qPCR is a better diagnostic alternative than conventional RUT, and is similar to histology by Giemsa stain in the detection of H. pylori, by which the test could be used for non-invasive diagnosis in clinical practice.

Gastric bacterial Flora in patients Harbouring Helicobacter pylori with or without chronic dyspepsia: analysis with matrix-assisted laser desorption ionization time-of-flight mass spectroscopy

Background

The gastric microbiota has recently been implicated in the causation of organic/structural gastroduodenal diseases (gastric and duodenal ulcers, gastric cancer) in patients with Helicobacter pylori (H. pylori) infection. We aimed to ascertain, in patients harbouring H. pylori, the role of the gastric microbiota in the causation of symptoms (chronic dyspepsia) in the absence of organic disease.

Methods

Seventy-four gastric biopsy samples obtained at endoscopy from patients with (n = 21) or without (n = 53) chronic dyspepsia, and that tested positive by the bedside rapid urease test for H. pylori infection, were cultured for detection of H. pylori and non-H. pylori organisms. The cultured organisms were identified by matrix-assisted laser desorption ionization time-of-flight mass spectroscopy (MALDI-TOF MS).

Results

A total of 106 non-H. pylori isolates were obtained from 74 patients’ samples. This included 33 isolates (median 2, range 1–2 per patient) from dyspeptic and 73 (median 2, range 1–2 per patient) from non-dyspeptic patients. These were identified from the Bruker Biotyper 2 database as Staphylococcus spp., Streptococcus spp., Lactobacillus spp., Micrococcus spp., Enterococcus spp., Pseudomonas spp., Escherichia spp., Klebsiella spp. and Bacillus spp., Staphylococcus and Lactobacillus were identified significantly more commonly in dyspeptics and Streptococcus, Pseudomonas, Escherichia coli and Klebsiella pneumoniae in non-dyspeptics. All identified organisms belonged to the phyla Firmicutes and Proteobacteria.

Conclusions

There is a qualitative difference in the gastric microbial spectrum between patients harbouring H. pylori with and without chronic dyspepsia. Whether these organisms have an independent role in the development or prevention of dyspepsia or act in concurrence with H. pylori needs study.

Preliminary opinion on assessment categories of stomach ultrasound report and data system (Su-RADS)

OBJECTIVE

Transabdominal ultrasound after oral administration of an echoic cellulose-based gastric ultrasound contrast agent (TUS-OCCA) has recently been suggested as a valuable mass-screening tool for gastric cancer. The aim of this study was to propose a producible stomach ultrasound reporting and data system (Su-RADS) using TUS-OCCA for gastric cancer screening.

PATIENTS

The study includes information of 2738 patients who underwent both gastroscopy and TUS-OCCA examinations recorded in software system. Gastroscopy examination with pathological diagnosis was considered as gold standard. Various gastric lesions were classified into category 1-5 based on gastric wall thicknesses of them (especially the mucosa layer).

RESULTS

The total malignant ratios of patients enrolled in this study were 17.1% (469/2738). The malignant ratios for category 1-5 were, respectively, 1.1, 1.7, 12.2, 34.2 and 78.1%. Category 2 indicated mild thickening of gastric wall at low risk for malignancy (1.7%); category 3 indicated moderate thickening at moderate risk for malignancy (12.2%); category 4 indicated severe thickening at high risk for malignancy (34.2%); category 5 indicated extremely severe thickening at extremely high risk for malignancy (78.1%). If category 2 was identified as cut-off point distinguishing between benign and malignant, the sensitivity and specificity by Su-RADS are 95.1 and 78.6%, respectively.

CONCLUSION

The Su-RADS system could inform the physicians about key findings, indicating the risk for malignancy and necessity of additional gastroscopy examination. Prospectively randomly controlled study design with larger clinical trial is needed for further investigations.

Dietary PUFA Increase Apoptosis in Stomach of Patients with Dyspeptic Symptoms and Infected with H. pylori

Drug-resistant strains of Helicobacter pylori and poor treatment response are the main reasons for the failure in eradicating it in patients. Polyunsaturated fatty acids (PUFA) have an inhibitory effect on bacterial growth. The aim of this study was to investigate the effect of PUFA in combination with standard triple therapy on apoptosis in H. pylori infected subjects with dyspeptic symptoms. This study was a double-blind clinical trial in which 34 H. pylori infected subjects with dyspeptic symptoms were randomly divided into two groups of 17 patients. The control group received standard triple therapy (amoxicillin, clarithromycin and omeprazole) and the experimental group received the standard therapy and PUFA for two weeks. Gene expression levels of caspase-3, BCL-2 and Bad proteins were studied with real-time PCR, while protein levels were quantified in frozen sections and using immunohistochemistry. Compared with the control group, a significant increase (p < 0.01) was observed in the expression of caspase-3 and Bad genes and a significant reduction (p < 0.05) in the expression of Bcl-2 gene. The protein level of active caspase-3 and Bad protein was significantly increased and the level of Bcl-2 protein was significantly decreased (p < 0.05). The results of this study show that oral administration of PUFA in combination with the standard triple therapy increased apoptosis in H. pylori-infected patients with dyspeptic symptoms. This increase in apoptosis may partly reduce drug resistance in these patients. Our results suggest inclusion of a dietary PUFA containing fatty acid supplement may improve treatment of patients that are refractory to the standard triple therapy.

Burden of preventable cancers in India: Time to strike the cancer epidemic

India has a rapidly growing population inflicted with cancer diagnosis. From an estimated incidence of 1.45 million cases in 2016, the cancer incidence is expected to reach 1.75 million cases in 2020. With the limitation of facilities for cancer treatment, the only effective way to tackle the rising and humongous cancer burden is focusing on preventable cancer cases. Approximately, 70% of the Indian cancers (40% tobacco related, 20% infection related and 10% others) are caused by potentially modifiable and preventable risk factors. We review these factors with special emphasis on the Indian scenario. The results may help in designing preventive strategies for a wider application.

Helicobacter pylori associated Asian enigma: Does diet deserve distinction?

Helicobacter pylori (H. pylori) is one of the most widespread infections in humans worldwide that chronically infects up to 50% of the world’s population. The infection is involved in the pathogenesis of chronic active gastritis, peptic ulcer, mucosa-associated lymphoid tissue lymphoma and gastric cancer, therefore, it has been classified as class I definite carcinogen by the World Health Organization. Despite the established etiological role of H. pylori, its actual distribution and association with related diseases is controversial and there is a large intercountry variation especially among Asian countries. H. pylori infection is more frequent in developing countries like India, Pakistan, and Bangladesh as compared to developed Asian countries like Japan, China and South Korea. However, the frequency of gastric cancer is comparatively lower in India, Pakistan, and Bangladesh with that of Japan, China and South Korea. Such phenomenon of clinical diversity, defined as enigma, is judged by genetic variability of the infecting H. pylori strains, differences in the host genetic background in various ethnic groups, and environmental factors such as dietary habits. Most of the studies have so far focused on the bacterial factor while environmental issues, including dietary components, were not given due attention as one of the factors related with H. pylori associated gastric carcinogenesis. The dietary factor has been suggested to play an important role in H. pylori related carcinogenesis, and in this respect several studies have corroborated the intake of various dietary components as modulatory factors for gastric cancer risk. In this review, such studies, from in vitro experiments to clinical trials, are being focused in detail with respect to enigma associated with H. pylori. It may be conceivably concluded from the available evidence that dietary factor can be a game changer in the scenario of Asian enigma, particularly in high risk population infected with virulent H. pylori strains, however further affirmation studies are desperately needed to achieve conclusive outcomes.

Characteristics and Risk Factors of Helicobacter pylori Associated Gastritis: A Prospective Cross-Sectional Study in Northeast Thailand

Background and Aim. Risk factors for Helicobacter pylori infection are genetic susceptibility and poor living conditions. This study aimed to investigate the Mdm2 gene, clarithromycin resistance, and possible risk factors for Helicobacter pylori infection. Methods. Risk factors and clinical characteristics were analyzed, including patient demographic data, patient income, personal history, possible source of transmission, patient symptoms, endoscopic findings, patterns of clarithromycin resistance, and patterns of Mdm2 SNIP309. Results. Ingestion of pickled fish (OR = 11.27, 95% CI = 4.31-29.45, p < 0.0001), salt crab (OR = 8.83, 95% CI = 1.99-39.14, p < 0.001), and Papaya salad (OR = 8.73, 95% CI = 4.54-16.79, p < 0.01). The prevalence of clarithromycin resistance was 56% (wild type, A2143/2142A, is 23.8%; mutation, A2143/2142CG, is 35.7%; wild type + mutation is 40.5%). The genetic polymorphisms of Mdm2 SNIP309 were SNIP309 T/T homozygous in 78%, SNIP309 G/T heterozygous in 19%, and SNIP309 G/G homozygous in 3%. Conclusion. Pickled fish, salt crab, and Papaya salad are positive risk factors. There was high prevalence of clarithromycin resistance. The Mdm2 SNIP309 G/G homozygous genotype might be a risk factor for gastric cancer and the fact that it is infrequent in Thailand.

Severe Anemia and Helicobacter Pylori Infection in school age Children; A case reports

BACKGROUND

Iron-deficiency anemia is a widespread public health problem with major consequences for human health especially, children. However, in a fraction of patients an underlying cause is never found during routine investigation. Recent studies have suggested an association between Helicobacter pylori (H. Pylori) infection and iron-deficiency anemia.

CASE PRESENTATION

Here is reported four school aged children (two male, two female) with refractory severe iron-deficiency anemia associated H. Pylori gastritis. Mean age of the patients was 13.62 years old and they were admitted with chief complaints of abdominal, chest pain weakness, headache and respiratory distress. Mean hemoglobin level in patients was 6.2 g/dl with persistence to iron therapy. After the diagnosis and therapy of H. pylori infection, clinical complaints, hemoglobin level and iron profiles were being normal and they gained weight.

CONCLUSION

This study suggests screening of H. pylori infection and appropriate treatment in any case of refractory moderate to severe iron-deficiency anemia, especially with clinical manifestations of gastrointestinal tract in children.

Gastric cancer risk in relation to tobacco use and alcohol drinking in Kerala, India - Karunagappally cohort study

AIM: To assess the risk of gastric cancer (GC) in relation to tobacco use and alcohol drinking in the Karunagappally cohort in Kerala, South India.

METHODS: This study examined the association of tobacco use and alcohol drinking with GC incidence among 65553 men aged 30-84 in the Karunagappally cohort. During the period from 1990-2009, 116 GC cases in the cohort were identified as incident cancers. These cases were identified from the population-based cancer registry. Information regarding risk factors such as socioeconomic factors and tobacco and alcohol habits of cohort members were collected from the database of the baseline survey conducted during 1990-1997. The relative risks (RRs) and the corresponding 95% confidence intervals (95%CIs) for tobacco use were obtained from Poisson regression analysis of grouped survival data, considering age, follow-up period, occupation and education.

RESULTS: Bidi smoking was associated with GC risk (P = 0.042). The RR comparing current versus never smokers was 1.6 (95%CI: 1.0-2.5). GC risk was associated with the number of bidis smoked daily (P = 0.012) and with the duration of bidi smoking (P = 0.036). Those who started bidi smoking at younger ages were at an elevated GC risk; the RRs for those starting bidi smoking under the age of 18 and ages 18-22 were 2.0 (95%CI: 1.0-3.9) and 1.8 (95%CI: 1.1-2.9), respectively, when their risks were compared with lifetime non-smokers of bidis. Bidi smoking increased the risk of GC among never cigarette smokers more evidently (RR = 2.2; 95%CI: 1.3-4.0). GC risk increased with the cumulative amount of bidi smoking, which was calculated as the number of bidis smoked per day x years of smoking (bidi-year; P = 0.017). Cigarette smoking, tobacco chewing or alcohol drinking was not significantly associated with GC risk.

CONCLUSION: Among a male cohort in South India, gastric cancer risk increased with the number and duration of bidi smoking.

Helicobacter pylori infection and a P53 codon 72 single nucleotide polymorphism: a reason for an unexplained Asian enigma

AIM

P53, the most commonly mutated tumor suppressor gene in all types of human cancer, is involved in cell cycle arrest and control of apoptosis. Although p53 contains several polymorphic sites, the codon 72 polymorphism is by far more common. There are divergent reports but many studies suggest p53 pro/pro SNP may be associated with susceptibility to developing various cancers in different regions of the world. The present study aimed to find any correlation between H. pylori infection and progression of carcinogenesis, by studying apoptosis and the p53 gene in gastric biopsies from north Indian population.

MATERIALS AND METHODS

A total of 921 biopsies were collected and tested for prevalence of H. pylori by rapid urease test (RUT), imprint cytology and histology. Apoptosis was studied by the TUNEL method. Analysis of p53 gene polymorphism at codon 72 was accomplished by PCR using restriction enzyme BstU1.

OBSERVATION

Out of 921 samples tested 56.7% (543) were H. pylori positive by the three techniques. The mean apoptotic index (AI) in the normal group was 2.12, while gastritis had the maximum 4.24 followed by gastric ulcer 2.28, gastropathy 2.22 and duodenal ulcer 2.08. Mean AI in cases with gastric cancer (1.72) was less than the normal group. The analysis of p53 72 SNP revealed that p53 (Arg/Arg), (Pro /Arg) variant are higher (40.59% and 33.66%) as compared to p53 pro/pro variant (25.74%) in the healthy population.

CONCLUSIONS

The North Indian population harbors Arg or Pro/Arg SNP that is capable of withstanding stress conditions; this may be the reason of low incidence of gastric disease in spite of high infection with H. pylori. There was no significant association with H. pylori infection and AI. However, there is increased apoptosis in gastritis which may occur independent of H. pylori or p53 polymorphism.

Allergies, Helicobacter pylori and the continental enigmas

Helicobacter pylori, a gastric pathogen, is known to be associated with gastric and duodenal ulcers, and is also a strong risk factor for the development of gastric cancer and lymphoma of the mucosal-associated lymphoid tissue. Ordinarily, this should make a strong case for its eradication at par with any other infectious disease. However, the unique biology of H. pylori and the complexity of its interactions with humans, its only known natural host, do not permit the recommendation of unambiguous preventive and therapeutic measures. Moreover, this organism has co-evolved with humans as a practically universal member of the natural gastric microbiota over at least 100,000 years. H. pylori persists for a lifetime in mostly asymptomatic hosts, and causes clinical disease only in a minority of infections. Therefore, its potential contribution to the maintenance of human immune homeostasis, as is the case with the better-studied members of the intestinal microbiota, is certainly worthy of serious investigation. In this paper, we summarize some interesting and often anecdotal data drawn from recent studies, and examine their significance in the context of the hygiene hypothesis. We also examine whether the lower incidence of gastric cancer over large parts of the world in spite of a high prevalence of infection (the Asian and African enigmas) may be re-interpreted in terms of the hygiene hypothesis. Finally, it is suggested that an evolutionary-ecological approach to the study of H. pylori infection may help in the formulation of strategies for the management of this infection. This may well be an infectious disease wherein medical interventions may have to be personalized to ensure optimal outcomes.

Association of Intact dupA (dupA1) rather than dupA1 cluster with duodenal ulcer in Indian population

Background

The duodenal ulcer promoting gene (dupA) and dupA cluster in Helicobacter pylori have been described as a risk factor for duodenal ulcer development in some populations. Polymorphic gene dupA can be divided into two groups, intact dupA1 (long or short type based on the presence or absence of 615-bp extra sequences at the 5′ region) having complete reading frame and other truncated dupA2 having frame-shift mutation. This study was aimed to elucidate the role of dupA of H. pylori and their clusters in the disease manifestation of Indian population.

Methods

A total of 170 H. pylori strains were screened for the presence of dupA, dupA alleles and dupA cluster by PCR and sequencing. Pro-inflammatory cytokine (IL-8) with different dupA variant H. pylori stimulated gastric epithelial cells (AGS cells) was measured by ELISA.

Results

A total of 50 strains (29.4%) were positive for dupA among the tested 170 strains. The prevalence of dupA1 in duodenal ulcer (DU) and non-ulcer dyspepsia (NUD) populations was found to be 25.5% (25/98) and 11.1% (8/72), respectively and 16.4% (28/170) of the tested strains had dupA1, cagA and vacAs1m1 positive. The distribution of long and short type dupA1 has not been significantly associated with the disease outcome. The dupA cluster analysis showed that 10.2% (10/98) and 8.3% (6/72) strains were positive among DU and NUD, respectively. IL-8 production was significantly higher in dupA1⁺, cagA⁺, vacA⁺ (902.5 ± 79.01 pg/mL) than dupA2⁺, cagA⁺, vacA⁺ (536.0 ± 100.4 pg/mL, P = 0.008) and dupA⁻, cagA⁺, vacA⁺ (549.7 ± 104.1 pg/mL, P = 0.009). Phylogenetic analysis of dupA indicated that the Indian H. pylori strains clustered with East Asian strains but distinct from Western strains. This is the first known genetic element of Indian H. pylori that is genetically closer to the East Asian strains but differed from the Western strains.

Conclusions

The intact dupA1 was significantly associated with DU than NUD (P = 0.029) but the dupA1 cluster has no role in the disease manifestation at India (P = 0.79). Thus, dupA1 can be considered as a biomarker for DU patients in India.

Helicobacter pylori: Genomic Insight into the Host-Pathogen Interaction

The advent of genomic analyses has revolutionized the study of human health. Infectious disease research in particular has experienced an explosion of bacterial genomic, transcriptomic, and proteomic data complementing the phenotypic methods employed in traditional bacteriology. Together, these techniques have revealed novel virulence determinants in numerous pathogens and have provided information for potential chemotherapeutics. The bacterial pathogen, Helicobacter pylori, has been recognized as a class 1 carcinogen and contributes to chronic inflammation within the gastric niche. Genomic analyses have uncovered remarkable coevolution between the human host and H. pylori. Perturbation of this coevolution results in dysregulation of the host-pathogen interaction, leading to oncogenic effects. This review discusses the relationship of H. pylori with the human host and environment and the contribution of each of these factors to disease progression, with an emphasis on features that have been illuminated by genomic tools.