Influence of interleukin polymorphisms on development of gastric cancer and peptic ulcer

Pro-inflammatory cytokines are produced in the gastric mucosa by inflammatory cells activated by chronic Helicobacter pylori (H. pylori) infection. Polymorphisms of these cytokine genes are associated with individual differences in gastric mucosal cytokine mRNA level, which result in differences in gastric mucosal inflammation, acid inhibition and gastroduodenal disease risk in response to H. pylori infection. Although polymorphisms of interleukin (IL)-1B, IL-1RN and TNF-A have been reported to relate well with gastric cancer and peptic ulcer risk, those of IL-2, IL-4, IL-6 and IL-8 genes are unclear. In combined analyses using data from previous studies, we found that the risk of gastric non-cardia cancer development was significantly associated with IL-4-168 C allele (OR: 0.81, 95% CI: 0.69-1.00) and IL-4-590 T allele carrier status (0.61, 0.53-0.73), and IL-6-174 G/G genotype (2<Abstract>Pro-inflammatory cytokines are produced in the gastric mucosa by inflammatory cells activated by chronic Helicobacter pylori (H. pylori) infection. Polymorphisms of these cytokine genes are associated with individual differences in gastric mucosal cytokine mRNA level, which result in differences in gastric mucosal inflammation, acid inhibition and gastroduodenal disease risk in response to H. pylori infection. Although polymorphisms of interleukin (IL)-1B, IL-1RN and TNF-A have been reported to relate well with gastric cancer and peptic ulcer risk, those of IL-2, IL-4, IL-6 and IL-8 genes are unclear. In combined analyses using data from previous stud- ies, we found that the risk of gastric non-cardia cancer development was significantly associated with IL-4-168 C allele (OR: 0.81, 95% CI: 0.69-1.00) and IL-4-590 T allele carrier status (0.61, 0.53-0.73), and IL-6-174 G/G genotype (2.02, 1.31-3.10). In peptic ulcer development, IL-2-330 G and IL-4-590 T allele carriers had a significantly decreased risk (0.37, 0.27-0.50 and 0.58, 0.34-0.99, respectively). Moreover, IL-2, IL-4, IL-6 and IL-8 gene genotypes prevalence differs among popula- tions. The inflammatory cytokine gene polymorphisms (e.g. IL-4 -590 and IL-6 -572 for gastric cancer, and IL-4-590, IL-6-572 and IL-8-251 for peptic ulcer) have a more potent influence on development of gastroduo- denal diseases in Western than East Asian populations. These cytokine gene polymorphisms, as well as those of IL-1B, IL-1RN and TNF-A, may be used to identify groups at higher risk of gastric cancer and peptic ulcer, and those suitable for their prevention by H. pylori eradication therapy in Western populations..02, 1.31-3.10). In peptic ulcer development, IL-2-330 G and IL-4-590 T allele carriers had a significantly decreased risk (0.37, 0.27-0.50 and 0.58, 0.34-0.99, respectively). Moreover, IL-2, IL-4, IL-6 and IL-8 gene genotypes prevalence differs among populations. The inflammatory cytokine gene polymorphisms (e.g. IL-4 -590 and IL-6 -572 for gastric cancer, and IL-4-590, IL-6-572 and IL-8-251 for peptic ulcer) have a more potent influence on development of gastroduo-denal diseases in Western than East Asian populations. These cytokine gene polymorphisms, as well as those of IL-1B, IL-1RN and TNF-A, may be used to identify groups at higher risk of gastric cancer and peptic ulcer, and those suitable for their prevention by H. pylori eradication therapy in Western populations.

Chemoprevention of gastric cancer development after Helicobacter pylori eradication therapy in an East Asian population:Meta-analysis

BACKGROUND Helicobacter pylori(H.pylori)infection is a risk factor for gastric cancer(GC),especially in East Asian populations.Most East Asian populations infected with H.pylori are at higher risk for GC than H.pylori-positive European and United States populations.H.pylori eradication therapy reduces gastric cancer risk in patients after endoscopic and operative resection for GC,as well as in non-GC patients with atrophic gastritis.AIM To clarify the chemopreventive effects of H.pylori eradication therapy in an East Asian population with a high incidence of GC.METHODS PubMed and the Cochrane library were searched for randomized control trials(RCTs)and cohort studies published in English up to March 2019.Subgroup analyses were conducted with regard to study designs(i.e.,RCTs or cohort studies),country where the study was conducted(i.e.,Japan,China,and South Korea),and observation periods(i.e.,≤5 years and>5 years).The heterogeneity and publication bias were also measured.RESULTS For non-GC patients with atrophic gastritis and patients after resection for GC,4 and 4 RCTs and 12 and 18 cohort studies were included,respectively.In RCTs,the median incidence of GC for the untreated control groups and the treatment groups was 272.7(180.4–322.4)and 162.3(72.5–588.2)per 100000 person-years in non-GC cases with atrophic gastritis and 1790.7(406.5–2941.2)and 1126.2(678.7–1223.1)per 100000 person-years in cases of after resection for GC.Compared with non-treated H.pylori-positive controls,the eradication groups had a significantly reduced risk of GC,with a relative risk of 0.67[95%confidence interval(CI):0.47–0.96]for non-GC patients with atrophic gastritis and 0.51(0.36–0.73)for patients after resection for GC in the RCTs,and 0.39(0.30–0.51)for patients with gastritis and 0.54(0.44–0.67)for patients after resection in cohort studies.CONCLUSION In the East Asian population with a high risk of GC,H.pylori eradication effectively reduced the risk of GC,irrespective of past history of previous cancer.

Roles of Helicobacter pylori BabA in gastroduodenal pathogenesis

Interactions between BabA and Lewis b (Leb) related antigens are the best characterized adhesin-receptor interactions in Helicobacter pylori (H pylori). Several mechanisms for the regulation of BabA expression are predicted, including at both transcriptional and translational levels. The formation of chimeric proteins (babA /B or babB /A chimeras) seems to play an especially important role in translational regulation. Chimeric BabB/A protein had the potential to bind Leb; however, protein production was subject to phase variation through slipped strand mispairing. The babA gene was cloned initially from strain CCUG17875, which contains a silent babA1 gene and an expressed babA2 gene. The sequence of these two genes differs only by the presence of a 10 bp deletion in the signal peptide sequence of babA1 that eliminates its translational initiation codon. However, the babA1 type deletion was found only in strain CCUG17875. A few studies evaluated BabA status by immunoblot and confirmed that BabA-positive status in Western strains was closely associated with severe clinical outcomes. BabA-positive status also was associated with the presence of other virulence factors (e.g. cagA-positive status and vacA s1 genotype). A small class of strains produced low levels of the BabA protein and lacked Leb binding activity. These were more likely to be associated with increased mucosal inflammation and severe clinical outcomes than BabA-positive strains that exhibited Leb binding activity. The underlying mechanism is unclear, and further studies will be necessary to investigate how the complex BabA-receptor network is functionally coordinated during the interaction of H pylori with the gastric mucosa.

Prevalence of Helicobacter pylori infection and atrophic gastritis in patients with dyspeptic symptoms in Myanmar

AIM: To survey the detailed analyses for Helicobacter pylori(H. pylori) infection and gastric mucosal status in Myanmar.METHODS: A total of 252 volunteers with dyspeptic symptoms(155 female and 97 male; mean age of 43.6 ± 14.2 years) was participated in Yangon and Mandalay. The status of H. pylori infection was determined based on 5 different tests including rapid urease test, culture, histology, immunohistochemistry and serology. Histological scores were evaluated according to the update Sydney system and the Operative Link for Gastritis Assessment system. Pepsinogen(PG)Ⅰand PG Ⅱ were measured using enzyme-linked immunosorbent assays.RESULTS: The overall prevalence of H. pylori infectionwas 48.0%. There was no relationship between age and infection rate. Even in young group(less than 29 years old), the H. pylori infection rate was relatively high(41.9%). The prevalence of H. pylori infection was significantly higher in Yangon than that of Mandalay. H. pylori infection was significantly associated with the presence of gastric mucosal atrophy. All 7 subjects with peptic ulcer were infected with H. pylori. Although H. pylori-positive subjects showed stronger gastritis than H. pylori-negative subjects, most cases had mild gastritis.CONCLUSION: We revealed the prevalence of H. pylori infection in patients with dyspeptic symptoms in Myanmar. The H. pylori infection was a risk factor for peptic ulcer and stronger gastritis.

Helicobacter pylori Bab A in adaptation for gastric colonization

Helicobacter pylori(H. pylori) as a causative agent of gastric complications, is well adapted for the colonization of gastric mucosa. Although the infectious process depends on several factors, the adhesion to the gastric mucosa is the first and important step. Among several outer membrane proteins, Bab A is one of the significant protein involving in many inflammatory processes in addition to its role in the attachment for the persistent colonization. We performed a Pub Med search using the key words: "bab A ", "pylori", "gastric complications", "homologous recombination", "slipped strand mispairing"; a total of 249 articles were displayed. Of these we mainly focused on articles with the full text in English and published between 2005 and 2016. H. pylori Bab A is involved in binding with receptors; however, its synthesis is regulated by phase variation. In this review we confirm that H. pylori bab A can be modulated at the molecular and functional levels to adapt to the stress within the gastro-intestinal tract.

Extremely high prevalence of Helicobacter pylori infection in Bhutan

AIM: To revealed the prevalence of Helicobacter pylori (H. pylori ) infection in the Bhutanese population. METHODS: We recruited a total of 372 volunteers (214 females and 158 males; mean age of 39.6 ± 14.9 years) from three Bhutanese cities (Thimphu, Punaka, and Wangdue). The status of H. pylori infection was determined based on five different tests: the rapid urease test (CLO test), culture, histology, immunohistochemistry (IHC), and serum anti H. pylori -antibody. RESULTS: The serological test showed a significantly higher positive rate compared with the CLO test, culture, histology and IHC (P < 0.001, P < 0.001, P=0.01, and P=0.01, respectively). When the subjects were considered to be H. pylori positive in the case of at least one test showing a positive result, the overall prevalence of H. pylori infection in Bhutan was 73.4%. The prevalence of H. pylori infection significantly decreased with age (P < 0.01). The prevalence of H. pylori infection was lower in Thimphu than in Punakha and Wangdue (P=0.001 and 0.06, respectively). The prevalence of H. pylori infection was significantly higher in patients with peptic ulcers than in those with gastritis (91.4% vs 71.3%, P=0.003). CONCLUSION: The high incidence of gastric cancer in Bhutan may be attributed to the high prevalence of H. pylori infection.

Antibiotics resistance rate of Helicobacter pylori in Bhutan

AIM:To survey the antibiotic resistance pattern of Helicobacter pylori(H.pylori)strains isolated from Bhutanese population.METHODS:We isolated 111 H.pylori strains from the gastric mucosa of H.pylori-infected patients in Bhutan in 2010.The Epsilometer test was used to determine the minimum inhibitory concentrations(MICs)of amoxicillin(AMX),clarithromycin(CLR),metronidazole(MNZ),levofloxacin(LVX),ciprofloxacin(CIP),and tetracycline(TET).RESULTS:Nineteen of the isolated H.pylori strains were susceptible to all antibiotics tested.The isolated strains showed the highest rate of antibiotic resistance to MNZ(92/111,82.9%).Among the 92 MNZresistant strains,74 strains(80.4%)showed high-level resistance(MIC≥256 g/mL).Three strains were resistance to LVX(2.7%).These strains were also resistance to CIP.None of the strains showed resistance to CLR,AMX and TET.CONCLUSION:CLR-based triple therapy is a more effective treatment approach over MNZ-based triple therapy for H.pylori infection in Bhutan.

Diversity of Helicobacter pylori genotypes in Iranian patients with different gastroduodenal disorders

AIM:To investigate the diversity of Helicobacter pylori(H.pylori)genotypes and correlations with disease outcomes in an Iranian population with different gastroduodenal disorders.METHODS:Isolates of H.pylori from patients with different gastroduodenal disorders were analyzed after culture and identification by phenotypic and genotypic methods.Genomic DNA was extracted with the QIAamp DNA mini kit(Qiagen,Germany).After DNA extraction,genotyping was done for cagA,vacA(s and m regions),iceA(iceA1,iceA2)and babA with specific primers for each allele using polymerase chain reaction(PCR).All patients’pathologic and clinical data and their relation with known genotypes were analyzed by using SPSS version 19.0 software.2test and Fisher’s exact test were used to assess relationships between categorical variables.The level of statistical significance was set at P<0.05.RESULTS:A total of 71 isolates from 177 patients with different gastroduodenal disorders were obtained.Based on analysis of the cagA gene(positive or negative),vacA s-region(s1or s2),vacA m-region(m1or m2),iceA allelic type(iceA1and iceA2)and babA gene(positive or negative),twenty different genotypic combinations were recognized.The prevalence of cagA,vacA s1,vacA s2,vacA m1,vacA m2,iceA1,iceA2,iceA1+iceA2and babA were 62%,78.9%,19.7%,21.1%,78.9%,15.5%,22.5%,40.8%and 95.8%,respectively.Interestingly,evaluation of PCR results for cagA in 6 patients showed simultaneous existence of cagA variants according to their size diversities that proposed mixed infection in these patients.The most prevalent genotype in cagA-positive isolates was cagA+/vacAs1m2/iceA1+A2/babA+and in cagA-negative isolates was cagA-/vacAs1m2/iceA-/babA+.There were no relationships between the studied genes and histo-pathological findings(H.pylori density,neutrophil activity,lymphoid aggregation in lamina propria and glandular atrophy).The strains which carry cagA,vacAs1/m1,iceA2and babA genes showed significant associations with severe active chronic gastritis(P=0.011,0.025,0.020 and 0.031,respectively).The vacAs1genotype had significant correlation with the presence of the cagA gene(P=0.013).Also,babA genotype showed associations with cagA(P=0.024).In the combined genotypes,only cagA+/vacAs1m1/iceA2/babA+genotype showed correlation with severe active chronic gastritis(P=0.025).CONCLUSION:This genotyping panel can be a useful tool for detection of virulent H.pylori isolates and can provide valuable guidance for prediction of the clinical outcomes.

Geographical distribution of the incidence of gastric cancer in Bhutan

AIM: To estimate the prevalence of gastric cancer(GC) in a cohort of patients diagnosed with GC and to compare it with patients diagnosed with all other types of gastro-intestinal(GI) cancer during the same period.METHODS: Between 2008 and 2013,five-year period,the medical records of all GI cancer patients who underwent medical care and confirm diagnosis of cancer were reviewed at the National Referral Hospital,Thimphu which is the only hospital in the country where surgical and cancer diagnosis can be made. Demographic information,type of cancer,and the year of diagnosis were collected.RESULTS: There were a total of 767 GI related cancer records reviewed during the study period of which 354(46%) patients were diagnosed with GC. There were 413 patients with other GI cancer including; esophagus,colon,liver,rectum,pancreas,gall bladder,cholangiocarcinoma and other GI tract cancers. The GC incidence rate is approximately 0.9/10000 per year(367 cases/5years per 800000 people). The geographic distribution of GC was the lowest in the south region of Bhutan 0.3/10000 per year compared to the central region 1.4/10000 per year,Eastern region 1.2/10000 per year,and the Western region 1.1/10000 per year. Moreover,GC in the South part was significantly lower than the other GI cancer in the same region(8% vs 15%; OR = 1.8,95%CI: 1.3-3.1,P = 0.05). Among GC patients,38% were under the age of 60 years,mean age at diagnosis was 62.3(± 12.1) years with male-to-female ratio 1:0.5. The mean age among patients with all other type GI cancer was 60 years(± 13.2) and male-tofemale ratio of 1:0.7. At time of diagnosis of GC,342(93%) were at stage 3 and 4 of and by the year 2013; 80(23%) GC patients died compared to 31% death among patients with the all other GI cancer(P = 0.08).CONCLUSION: The incidence rate of GC in Bhutan is twice as high in the United States but is likely an underestimate rate because of unreported and undiagnosed cases in the villages. The high incidence of GC in Bhutan could be attributed to the high prevalence of Helicobacter pylori infection that we previously reported. The lowest incidence of GC in Southern part of the country could be due to the difference in the ethnicity as most of its population is of Indian and Nepal origin. Our current study emphasizes on the importance for developing surveillance and prevention strategies for GC in Bhutan.

Gastric mucosa in Mongolian and Japanese patients with gastric cancer and Helicobacter pylori infection

AIM: To investigate the characteristics of gastric cancer and gastric mucosa in a Mongolian populationby comparison with a Japanese population.METHODS: A total of 484 Mongolian patients with gastric cancer were enrolled to study gastric cancer characteristics in Mongolians. In addition, a total of 208 Mongolian and 3205 Japanese consecutive outpatients who underwent endoscopy, had abdominal complaints, no history of gastric operation or Helicobacter pylori eradication treatment, and no use of gastric secretion inhibitors such as histamine H2-receptor antagonists or proton pump inhibitors were enrolled. This study was conducted with the approval of the ethics committees of all hospitals. The triple-site biopsy method was used for the histologic diagnosis of gastritis and H. pylori infection in all Mongolian and Japanese cases. The infection rate of H. pylori and the status of gastric mucosa in H. pylori-infected patients were compared between Mongolian and Japanese subjects. Age(± 5 years), sex, and endoscopic diagnosis were matched between the two countries.RESULTS: Approximately 70% of Mongolian patients with gastric cancer were 50-79 years of age, and approximately half of the cancers were located in the upper part of the stomach. Histologically, 65.7% of early cancers exhibited differentiated adenocarcinoma, where as 73.9 % of advanced can cersdisplayed undifferentiated adenocarcinoma. The infection rate of H. pylori was higher in Mongolian than Japanese patients(75.9% vs 4 8. 3 %, P<0.0001). When stratified by age, the prevalence was highest among young patients, and tended to decrease in patients aged 50 years or older. The anti-East-Asian Cag Aspecific antibody was negative in 99.4% of H. pyloripositive Mongolian patients. Chronic inflammation, neutrophil activity, glandular atrophy, and intestinal metaplasia scores were significantly lower in Mongolian compared to Japanese H. pylori-positive patients(P < 0.0001), with the exception of the intestinal metaplasia score of specimen from the greater curvature of the upper body. The type of gastritis changed from antrumpredominant gastritis to corpus-predominant gastritis with age in both populations.CONCLUSION: Gastric cancer was located in the upper part of the stomach in half of the Mongolian patients; Mongolian patients were infected with non-East-Asiantype H. pylori.

Novel CagA ELISA exhibits enhanced sensitivity of Helicobacter pylori CagA antibody

AIM To develop a novel Helicobacter pylori(H.pylori)CagA antibody enzyme-linked immunosorbent assay(ELISA)suitable for detecting serum anti-CagA antibodies with high sensitivity.METHODS Recombinant East Asian-type CagA protein was purified and immobilized for ELISA.Serum samples from 217Vietnamese individuals(110 H.pylori-infected and107 uninfected individuals)were applied.Conventional ELISA from Western-type CagA and our East Asian-type CagA ELISA were evaluated by comparing 38 subjects with the Western-type genotype and 72 subjects with the East Asian-type cagA genotype.Histological scores of the gastric mucosa were determined using the updated Sydney System to examine the relationship with anti-CagA antibody titers.RESULTS Recombinant 70-100 k Da fragments were immobilized on the ELISA plate.In ROC analysis,the area under the curve of our East Asian-type CagA ELISA was comparable to that of conventional CagA ELISA.The sensitivity of the two ELISAs differed depending on the cagA genotype.The sensitivity of East Asian-type Cag A ELISA was higher for subjects infected with East Asiantype cagA H.pylori(P<0.001),and the sensitivity of the conventional CagA ELISA tended to be higher for subjects infected with Western cagA H.pylori(P=0.056).The titer of anti-CagA antibody tended to correlate with monocyte infiltration scores(r=0.25,P=0.058)and was inversely correlated with H.pylori density(r=-0.26,P=0.043).CONCLUSION The novel ELISA is useful to detect anti-CagA antibodies in East Asian countries,and the titer may be a marker for predicting chronic gastritis.

Discovery of unique African Helicobacter pylori CagAmultimerization motif in the Dominican Republic

BACKGROUND Helicobacter pylori(H.pylori)colonizes the human stomach and is a major cause of peptic ulcer disease and gastric cancer.However,although the prevalence of H.pylori is high in Africa,the incidence of gastric cancer is low,and this phenomenon is called to be African enigma.The CagA protein produced by H.pylori is the most studied virulence factor.The carcinogenic potential of CagA is associated with the Glu-Pro-Ile-Tyr-Ala(EPIYA)patterns and CagAmultimerization(CM)motifs.AIM To better understand the EPIYA patterns and CM motifs of the cagA gene.METHODS Gastric mucosal biopsy specimens were obtained from 258 patients with dyspepsia living in the Dominican Republic,from which 120 H.pylori strains were cultured.After the bacterial DNA extraction,the EPIYA pattern and CM motif genotypes were determined using a polymerase chain reaction-based sequencing.The population structure of the Dominican Republic strains was analyzed using multilocus sequence typing(MLST).Peptic ulcer disease and gastric cancer were identified via endoscopy,and gastric cancer was confirmed by histopathology.Histological scores of the gastric mucosa were evaluated using the updated Sydney system.RESULTS All CagA-positive strains carried the Western-type CagA according to the identified EPIYA patterns.Twenty-seven kinds of CM motifs were observed.Although the typical Western CM motif(FPLKRHDKVDDLSKVG)was observed most frequently,the typical East Asian CM motif(FPLRRSAAVNDLSKVG)was not observed.However,“FPLRRSAKVEDLSKVG”,similar to the typical East Asian CM motif,was found in 21 strains.Since this type was significantly more frequent in strains classified as hpAfrica1 using MLST analysis(P=0.034),we termed it Africa1-CM(Af1-CM).A few hpEurope strains carried the Af1-CM motif,but they had a significantly higher ancestral Africa1 component than that of those without the Af1-CM motif(P=0.030).In 30 cagA-positive strains,the"GKDKGPE"motif was observed immediately upstream of the EPIYA motif in the EPIYA-A segment,and there was a significant association between strains with the hpAfrica1 population and those containing the“GKDKGPE”motif(P=0.018).In contrast,there was no significant association between the CM motif patterns and histological scores and clinical outcomes.CONCLUSION We found the unique African CM motif in Western-type CagA and termed it Africa1-CM.The less toxicity of this motif could be one reason to explain the African enigma.

Detection of genotypic clarithromycin-resistant Helicobacter pylori by string tests

AIM:To evaluate the utility of the string test to detect genotypic clarithromycin-resistant Helicobacter pylori (H.pylori)by polymerase chain reaction(PCR)-restriction fragment length polymorphism.METHODS:Patients undergoing endoscopic examinations were enrolled in the present study.String tests were done on the next day of endoscopy.Segments of 23S rRNA were amplified from DNA obtained from string tests.PCR-restriction fragment length polymorphism was accomplished by restriction enzymes BbsI and BsaI recognizing the mutation site A to G at 2143or at 2142 of 23S rRNA domain V,respectively.RESULTS:One hundred and thirty-four patients with H.pylori infection underwent string tests.To compare phenotypic resistance,43 isolates were successfully cultured in 79 patients in whom 23S rRNA was successfully amplified.Of five patients with clarithromycinresistant H.pylori,23S rRNA of H.pylori isolates from four patients could be digested by BsaI.In 38 susceptible isolates,23S rRNA of H.pylori isolates from 36 patients could not be digested by either BsaI or BbsI.The sensitivity and specificity of the string test to detect genotypic clarithromycin resistance were 66.7%and97.3%,respectively.Positive and negative predictive values were 80%and 94.7%,respectively.CONCLUSION:String test with molecular analysis is a less invasive method to detect genotypic resistance before treatment.Further large-scale investigations are necessary to confirm our results.