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.     

Does the antibody production ability affect the serum anti-Helicobacter pylori IgG titer?

AIM: To investigate the relationship between serum titers of anti-Helicobacter pylori(H.pylori) immunoglobulin G(IgG) and hepatitis B virus surface antibody(HBsA b).METHODS: Korean adults were included whose samples had positive Giemsa staining on endoscopic biopsy and were studied in the hepatitis B virus surface antigen(HBsA g)/HBsA b serologic assay,pepsinogen(PG) assay,and H.pylori serologic test on the same day.Subjects were excluded if they were positive for HBs Ag,had a recent history of medication,or had other medical condition(s).We analyzed the effects of the following factors on serum titers of HBsA b and the anti-H.pylori IgG : Age,density of H.pylori infiltration in biopsy samples,serum concentrations of PG Ⅰ and PG Ⅱ,PG Ⅰ/Ⅱ ratio,and white blood cell count.RESULTS: Of 111 included subjects,74(66.7%) exhibited a positive HBsA b finding.The serum anti-H.pylori IgG titer did not correlate with the serum HBsA b titer(P = 0.185); however,it correlated with the degree of H.pylori infiltration on gastric biopsy(P 0.001) and serum PG Ⅱ concentration(P = 0.042).According to the density of H.pylori infiltration on gastric biopsy,subjects could be subdivided into those with a marked(median: 3.95,range 0.82-4.00)(P = 0.458),moderate(median: 3.37,range 1.86-4.00),and mild H.pylori infiltrations(median: 2.39,range 0.36-4.00)(P 0.001).Subjects with a marked H.pylori infiltration on gastric biopsy had the highest serological titer,whereas in subjects with moderate and mild H.pylori infiltrations titers were correspondingly lower(P 0.001).After the successful eradication,significant decreases of the degree of H.pylori infiltration(P 0.001),serum anti-H.pylori IgG titer(P 0.001),and serum concentrations of PG I(P = 0.028) and PG Ⅱ(P = 0.028) were observed.CONCLUSION: The anti-H.pylori IgG assay can be used to estimate the burden of bacteria in immunocompetent hosts with H.pylori infection,regardless of the HBsA b titer after HBV vaccination.     

Beyond the stomach: An updated view of Helicobacter pylori pathogenesis,diagnosis, and treatment

Helicobacter pylori (H. pylori) is an extremely common, yet underappreciated, pathogen that is able to alter host physiology and subvert the host immune response, allowing it to persist for the life of the host. H. pylori is the primary cause of peptic ulcers and gastric cancer. In the United States, the annual cost associated with peptic ulcer disease is estimated to be $6 billion and gastric cancer kills over 700000 people per year globally. The prevalence of H. pylori infection remains high (> 50%) in much of the world, although the infection rates are dropping in some developed nations. The drop in H. pylori prevalence could be a double-edged sword, reducing the incidence of gastric diseases while increasing the risk of allergies and esophageal diseases. The list of diseases potentially caused by H. pylori continues to grow; however, mechanistic explanations of how H. pylori could contribute to extragastric diseases lag far behind clinical studies. A number of host factors and H. pylori virulence factors act in concert to determine which individuals are at the highest risk of disease. These include bacterial cytotoxins and polymorphisms in host genes responsible for directing the immune response. This review discusses the latest advances in H. pylori pathogenesis, diagnosis, and treatment. Up-to-date information on correlations between H. pylori and extragastric diseases is also provided.     

Increased expression of matrix metalloproteinase-9 associated with gastric ulcer recurrence

AIM: To compare matrix metalloproteinase (MMP)-9 and tissue inhibitor of metalloproteinase (TIMP)-1 in gastric ulcer (GU) and chronic superficial gastritis (CSG). METHODS: This study enrolled 63 patients with GU and 25 patients with CSG. During upper gastroduodenal endoscopy, we took samples of gastric mucosa from the antrum and ulcer site from patients with GU, and samples of antral mucosa from patients with CSG. Mucosal biopsy tissues were cultured for 24 h, and the culture supernatant was measured for levels of MMP-9 and TIMP-1. After receiving eradication therapy for Helicobacter pylori (H. pylori ) and 8 wk proton-pump inhibitor therapy for GU, follow-up endoscopy examination was performed after 6 mo and whenever severe symptoms occurred. RESULTS: Levels of MMP-9 and TIMP-1 at the ulcer site or in the antrum were significantly higher in GU than CSG patients. MMP-9 levels at the ulcer site were significantly higher than in the antrum in GU patients, and had a significantly positive correlation with TIMP-1. MMP-9 levels were significantly higher in H. pylori -positive than H. pylori -negative GU and CSG patients. Levels of MMP-9 or TIMP-1 at the ulcer site were associated with the histological severity of activity and inflammation. About 57 GU patients were followed up, and seven had GU recurrence. H. pyloriinfection and MMP-9 levels were risk factors for the recurrence of GU adjusted for age and sex by multiple logistic regression analysis. CONCLUSION: MMP-9 may perform an important function in gastric ulcer formation and recurrence.     

Hematologic manifestations of Helicobacter pylori infection

Helicobacter pylori (H. pylori) is the most common infection in humans, with a marked disparity between developed and developing countries. Although H. pylori infections are asymptomatic in most infected individuals, they are intimately related to malignant gastric conditions such as gastric cancer and gastric mucosa-associated lymphoid tissue (MALT) lymphoma and to benign diseases such as gastritis and duodenal and gastric peptic ulcers. Since it was learned that bacteria could colonize the gastric mucosa, there have been reports in the medical literature of over 50 extragastric manifestations involving a variety medical areas of specialization. These areas include cardiology, dermatology, endocrinology, gynecology and obstetrics, hematology, pneumology, odontology, ophthalmology, otorhinolaryngology and pediatrics, and they encompass conditions with a range of clear evidence between the H. pylori infection and development of the disease. This literature review covers extragastric manifestations of H. pylori infection in the hematology field. It focuses on conditions that are included in international consensus and management guides for H. pylori infection, specifically iron deficiency, vitamin B₁₂ (cobalamin) deficiency, immune thrombocytopenia, and MALT lymphoma. In addition, there is discussion of other conditions that are not included in international consensus and management guides on H. pylori, including auto-immune neutropenia, antiphospholipid syndrome, plasma cell dyscrasias, and other hematologic diseases.     

Ins and outs of Helicobacter pylori association with autoimmune rheumatic diseases

Helicobacter pylori (H. pylori) infection is widely prevalent throughout worldwide. H. pylori manage a long-term survival in hostile environment of human stomach leading to peptic ulcer diseases and gastric cancer. But mostly infected person remains asymptomatic. Its chronic interaction with immune system makes H. pylori as an attractive candidate for the researchers to study its association with autoimmune diseases. This article presents a review of the literature on the association of H. pylori infection in selective autoimmune rheumatic diseases (RD). The authors used MeSH terms “Helicobacter pylori” with “rheumatoid arthritis,”“systemic lupus erythematosus,” or “fibromyalgia” to search PubMed database. All relevant studies identified were included. Despite extensive medical advancement many questions on role of H. pylori infection in autoimmune RD still remain unanswered. Further studies are therefore needed to address the role of H. pylori in pathogenesis of RD.     

Increased expression of tyrosine phosphatase SHP-2 in Helicobacter pylori-infected gastric cancer

AIM:To explore the alteration of tyrosine phosphatase SHP-2 protein expression in gastric cancer and to assess its prognostic values.METHODS:Three hundred and five consecutive cases of gastric cancer were enrolled into this study.SHP-2 expression was carried out in 305 gastric cancer specimens,of which 83 were paired adjacent normal gastric mucus samples,using a tissue microarray immunohistochemical method.Correlations were analyzed between expression levels of SHP-2 protein and tumor parameters or clinical outcomes.Serum anti-Helicobacter pylori(H.pylori) immunoglobulin G was detected with enzyme-linked immunosorbent assay.Cox proportional hazards model was used to evaluate prognostic values by compassion of the expression levels of SHP-2 and disease-specific survivals in patients.RESULTS:SHP-2 staining was found diffuse mainly in the cytoplasm and the weak staining was also observed in the nucleus in gastric mucosa cells.Thirty-two point five percent of normal epithelial specimen and 62.6% of gastric cancer specimen were identified to stain with SHP-2 antibody positively(P < 0.001).Though SHP-2 staining intensities were stronger in the H.pylori(+) group than in the H.pylori(-) group,no statistically significant difference was found in the expression levels of SHP-2 between H.pylori(+) and H.pylori(-) gastric cancer(P = 0.40).The SHP-2 expression in gastric cancer was not significantly associated with cancer stages,lymph node metastases,and distant metastasis of the tumors(P = 0.34,P = 0.17,P = 0.52).Multivariate analysis demonstrated no correlation between SHP-2 expression and disease-free survival(P = 0.86).CONCLUSION:Increased expression of SHP-2 protein in gastric cancer specimen suggesting the aberrant upregulation of SHP-2 protein might play an important role in the gastric carcinogenesis.     

Progress in elucidating the relationship between Helicobacter pylori infection and intestinal diseases

Helicobacter pylori (H. pylori) infection causes changes to the intestinal flora, such as small intestinal bacterial overgrowth, and increases gastric acid secretion-stimulating gastrointestinal hormones, mainly gastrin, due to a decrease in gastric acid caused by atrophic gastritis. In addition, the cellular components of H. pylori travel through the intestinal tract, so the bacterial infection affects the immune system. Therefore, the effects of H. pylori infection are observed not only in the stomach and the proximal duodenum but also in the small and large intestines. In particular, meta-analyses reported that H. pylori-infected individuals had an increased risk of colorectal adenoma and colorectal cancer. Moreover, a recent study reported that the risk of developing colorectal cancer was increased in subjects carrying H. pylori vacuolating cytotoxin A antibody. In addition, it has been reported that H. pylori infection exacerbates the symptoms of Fabry’s disease and familial Mediterranean fever attack and is involved in irritable bowel syndrome and small intestinal ulcers. On the other hand, some studies have reported that the frequency of ulcerative colitis, Crohn’s disease, and celiac disease is low in H. pylori-infected individuals. Thus, H. pylori infection is considered to have various effects on the small and large intestines. However, few studies have reported on these issues, and the details of their effects have not been well elucidated. Therefore, additional studies are needed.     

Chinese Helicobacter pylori vaccine: Solution for an old challenge?

Helicobacter pylori(H. pylori) is an important cause for gastric cancer in high risk individuals. H. pylori colonizes more than 50% of the world's population and associated peptic ulcer disease and gastric malignancy have important public health implications. It has been classified as a class Ⅰ carcinogen in 1994 by the World Health Organization. Clinicians are often prompted to eliminate the infection the moment it is detected. This also, unfortunately, led to reckless use of antibiotics and reports of increasing resistance are now worldwide. Each year, many of people die from gastric cancer; thus application of effective vaccine can reduce this relatively high mortality worldwide. H. pylori can be eliminated by antibiotics but efficacy is sharply decreasing. Moreover, current therapy is also expensive and with side effects. Vaccine may be the best solution to the above problem but there are many challenges in producing such an effective therapeutic vaccine. Recently, the Chinese group published in Lancet, a single-center, randomized, phase Ⅲ study of an oral recombinant vaccine(Urease B subunit fused with heat-labile enterotoxin B derived from Escherichia coli) prescribed in the Chinese children(6-15 years) without a history of H. pylori infection. This review provides an insight into this new solution for an old challenge.     

Standard triple versus levofloxacin based regimen for eradication of Helicobacter pylori

AIM: To compare the eradication rates for Helicobacter pylori (H. pylori) and ulcer recurrence of standard triple therapy (STT) and levofloxacin based therapy (LBT). METHODS: Seventy-four patients with perforated duodenal ulcer treated with simple closure and found to be H. pylori infected on 3 mo follow up were randomized to receive either the STT group comprising of amoxicillin 1 g bid, clarithromycin 500 mg bid and omeprazole 20 mg bid or the LBT group comprising of amoxicillin 1 g bid, levofloxacin 500 mg bid and omeprazole 20 mg bid for 10 d each. The H. pylori eradication rates, side effects, compliance and the recurrence of ulcer were assessed in the two groups at 3 mo follow up. RESULTS: Thirty-four patients in the STT group and 32 patients in the levofloxacin group presented at 3 mo follow up. H. pylori eradication rates were similar with STT and the LBT groups on intention-to-treat (ITT) analysis (69% vs 80%, P = 0.425) and (79% vs 87%, P = 0.513) by per-protocol (PP) analysis respectively. Ulcer recurrence in the STT and LBT groups on ITT analysis was (20% vs 14%, P = 0.551) and (9% vs 6%, P = 1.00) by PP analysis. Compliance and side effects were also comparable between the groups. A complete course of STT costs Indian Rupees (INR) 1060.00, while LBT costs only INR 360.00. CONCLUSION: H. pylori eradication rates and the rate of ulcer recurrence were similar between the STT and LBT. The LBT is a more economical option compared to STT.     

Dyspepsia, Helicobacter pylori, and peptic ulcer in a randomly selected population in India.

There seems to be a worldwide geographic variation in the prevalence of peptic ulcer disease, although there are few reliable population based studies. This study aimed to determine the prevalence of peptic ulcer disease in a community in southern India and to evaluate the relationship between dyspeptic symptoms, Helicobacter pylori infection, gastritis, and peptic ulcer disease. A sample population was selected randomly from a rural monastic settlement in southern India. Subjects were interviewed using a standardised symptom and demography questionnaire then underwent upper endoscopy and antral biopsy for histology and CLO rapid urease test. Altogether 197 subjects from a population of 1499 (13.1%) were studied. All were male monks and ethnically Tibetan. The median age was 28 years (range: 21-81). None smoked or took NSAIDs. The six month period prevalence of dyspeptic symptoms was 68.5%. Current symptoms were present in 58.9% of subjects. Dyspepsia was more common in subjects aged 40 years or younger (p < 0.0001). H pylori was detected in 77.2% subjects. There was no association between dyspepsia and the presence of H pylori or histological gastritis, although there was a strong correlation between symptoms and ulcer (p < 0.003). The point prevalence of active peptic ulcer was 6.6% (13/197). All ulcers detected were either prepyloric or pyloroduodenal in location. A further 6.6% of subjects had definite evidence of scarring or deformity indicative of ulceration in the past. Subjects with past or present ulcers comprised 17.8% of dyspeptic subjects. H pylori was present in all subjects with active ulcers and in 12/13 of those with scarring. Dyspepsia, H pylori infection, gastritis, and peptic ulcer are all more common in this population than in those from developed countries. Ulcer disease, however, accounts for only a small proportion of subjects with symptoms and neither H pylori infection nor gastritis are significantly associated with the presence of dyspepsia.     

Narrow-band imaging with magnifying endoscopy is accurate for detecting gastric intestinal metaplasia

AIM:To investigate the predictive value of narrowband imaging with magnifying endoscopy (NBI-ME) for identifying gastric intestinal metaplasia (GIM) in unselected patients. METHODS:We prospectively evaluated consecutive patients undergoing upper endoscopy for various indications, such as epigastric discomfort/pain, anaemia, gastro-oesophageal reflux disease, suspicion of peptic ulcer disease, or chronic liver diseases. Patients underwent NBI-ME, which was performed by three blinded, experienced endoscopists. In addition, five biopsies (2 antrum, 1 angulus, and 2 corpus) were taken and examined by two pathologists unaware of the endoscopic findings to determine the presence or absence of GIM. The correlation between light blue crest (LBC) appearance and histology was measured. Moreover, we quantified the degree of LBC appearance as less than 20% (+), 20%-80% (++) and more than 80% (+++) of an image field, and the semiquantitative evaluation of LBC appearance was correlated with IM percentage from the histological findings. RESULTS:We enrolled 100 (58 F/42 M) patients who were mainly referred for gastro-esophageal reflux disease/dyspepsia (46%), cancer screening/anaemia (34%), chronic liver disease (9%), and suspected celiac disease (6%); the remaining patients were referred for other indications. The prevalence of Helicobacter pylori (H. pylori ) infection detected from the biopsies was 31%, while 67% of the patients used proton pump inhibitors. LBCs were found in the antrum of 33 patients (33%); 20 of the cases were classified as LBC+, 9 as LBC++, and 4 as LBC+++. LBCs were found in the gastric body of 6 patients (6%), with 5 of them also having LBCs in the antrum. The correlation between the appearance of LBCs and histological GIM was good, with a sensitivity of 80% (95%CI:67-92), a specificity of 96% (95%CI:93-99), a positive predictive value of 84% (95%CI:73-96), a negative predictive value of 95% (95%CI:92-98), and an accuracy of 93% (95%CI:90-97). The NBI-ME examination overlooked GIM in 8 cases, but the GI     

Kyoto classification of gastritis: Advances and future perspectives in endoscopic diagnosis of gastritis

This editorial provides an update of the recent evidence on the endoscopy-based Kyoto classification of gastritis, clarifying the shortcomings of the Kyoto classification, and providing prospects for future research, with particular focus on the histological subtypes of gastric cancer (GC) and Helicobacter pylori (H. pylori) infection status. The total Kyoto score is designed to express GC risk on a score ranging from 0 to 8, based on the following five endoscopic findings: Atrophy, intestinal metaplasia (IM), enlarged folds (EF), nodularity, and diffuse redness (DR). The total Kyoto score reflects H. pylori status as follows: 0, ≥ 2, and ≥ 4 indicate a normal stomach, H. pylori-infected gastritis, and gastritis at risk for GC, respectively. Regular arrangement of collecting venules (RAC) predicts non-infection; EF, nodularity, and DR predict current infection; map-like redness (MLR) predicts past infection; and atrophy and IM predict current or past infection. Atrophy, IM, and EF all increase the incidence of H. pylori-infected GC. MLR is a specific risk factor for H. pylori-eradicated GC, while RAC results in less GC. Diffuse-type GC can be induced by active inflammation, which presents as EF, nodularity, and atrophy on endoscopy, as well as neutrophil and mononuclear cell infiltration on histology. In contrast, intestinal-type GC develops via atrophy and IM, and is consistent between endoscopy and histology. However, this GC risk-scoring design needs to be improved.     

Effect of Helicobacter pylori infection on gastric cell proliferation and genomic instability in a paediatric population of southern Italy.

Background. The incidence of gastric cancer is high in areas with a high prevalence of Helicobacter pylori infection. Cell transformation and tumour progression occur over a long period of time and markers of genomic instability usually precede morphological changes.

Aim. To evaluate the effect of Helicobacter pylori infection on cell proliferation, DNA status and oncogene expression in children.

Patients and Methods. Morphometric and immunohistochemical techniques were used to analyse DNA content, p53 and c-myc oncogene expression and cell proliferation on gastric biopsies of 53 children (27 Helicobacter pylori-negative and 26 Helicobacter pylori-positive).

Results. Gastric mucosa was normal in 11 % of Helicobacter pylori-positive and in 33% of Helicobacter pylori-negative subjects. Most children had chronic non-atrophic gastritis regardless of Helicobacter pylori infection, and only a minority of children affected by Helicobacter pylori had mild atrophic gastritis. Cell proliferation was significantly higher in children with Helicobacter pylori-positive gastritis than in those with Helicobacter pylori-negative gastritis. No metaplasia, dysplasia, p53 overexpression or altered DNA content was found in any child. Interestingly, 46% of children with and 29% without Helicobacter pylori infection had c-myc overexpression closely related to the cell proliferation rate.

Conclusion. Helicobacter pylori infection in children may coexist with a normal gastric mucosa, and it is not associated with genomic instability markers in cases of chronic gastritis.     

Effect of Helicobacter pylori eradication on serum ghrelin and obestatin levels

AIM: To investigate changes in serum ghrelin and obestatin levels before and after Helicobacter pylori (H. pylori ) eradication. METHODS: A total of 92 patients presenting with symptoms of dyspepsia were enrolled in the study. Upper endoscopy was performed on all patients and used to diagnose H. pylori infection according to the presence of characteristic histopathological findings; seventy patients were diagnosed with H. pylori infection and the remaining 22 non-infected patients were classified as healthy controls. H. pylori eradication was accomplished by administering the classical triple therapy drug regimen, consisting of lansoprazole 30 mg bid , amoxicillin 1 g bid , and clarithromycin 500 mg tid for 14 d. The eradication of H. pylori was assessed with C14-urea breath test, which was performed at eight weeks after treatment. Levels of serum active ghrelin and obestatin were assessed at beginning of the study (prior to treatment) and after eight weeks. The levels were comparatively analyzed between the H. pylori negative control group, the H. pylori eradicated group, and the H. pylori non-eradicated group. RESULTS: A total of 92 patients, 50 females and 42 males with a mean age of 38.2 ± 11.9 years (range: 19-64), were analyzed. H. pylori eradication success was achieved in 74.3% (52/70) of H. pylori positive patients. The initial levels of ghrelin in the H. pylori positive and control cases were 63.6 ± 19.8 pg/mL and 65.1 ± 19.2 pg/mL (P=0.78), respectively, and initial obestatin levels were 771±427 pg/mL and 830 ± 296 pg/mL (P=0.19), respectively. The difference between the initial levels and the week 8 levels of ghrelin and obestatin in the control group was insignificant [4.5% (P=0.30) and -0.9% (P=0.65), respectively]. The difference between the initial and week 8 levels of ghrelin and obestatin in the H. pylori non-eradicated group were also insignificant [0.9% (P=0.64) and 5.3% (P=0.32), respectively]. The H. pylori eradicated group had a greater change in obestatin levels when compared to the     

The association between CagA status and the development of esophagitis after the eradication of Helicobacter pylori

BACKGROUND: Strains of Helicobacter pylori with the cytotoxine-associated gene A (cagA) are linked to severe forms of gastroduodenal disease. Although eradication of H. pylori may predispose to the development of reflux esophagitis, the effects of CagA status on risk of esophagitis after successful H. pylori treatment are not known.

METHODS: We studied 50 consecutive patients without esophagitis in whom H. pylori was eradicated successfully. CagA status was determined by immunoblotting sera from patients against H. pylori antigens. Patients underwent upper gastrointestinal endoscopy before eradication and 6, 12, 18, and 24 months after eradication or when reflux symptoms occurred. Biopsy specimens of the antrum and corpus were evaluated for gastritis before H. pylori eradication and at the end of the study. The sum of the scores for acute and chronic inflammation (both measured on a 0 [absent] to 3 [severe] scale) comprised the total gastritis severity score.

RESULTS: In a multivariate proportional hazards regression analysis, positive CagA serology (hazard ratio [HR] = 10, 95% confidence interval [CI]: 1.3 to 81) and moderate-to-severe corpus gastritis (total severity score ≥4) before eradication (HR = 2.3, 95% CI: 1.2 to 6.1) were independent risk factors for the development of esophagitis after H. pylori eradication.

CONCLUSION: Patients infected with strains of H. pylori that are cagA-positive are at increased risk of developing esophagitis after eradication of H. pylori.     

Low peptic ulcer and high gastric cancer prevalence in a developing country with a high prevalence of infection by Helicobacter pylori

We compared the prevalence rates of peptic ulcer (duodenal and gastric) and gastric cancer in 1,796 dyspeptic Peruvian patients with those reported in 2,883 similar patients from developed countries. The prevalence of total peptic ulcer was significantly lower, and that of gastric cancer significantly higher, in the Peruvian patients. The prevalence of gastric ulcer was lower but not significantly so. We deduced that the significantly lower prevalence of total peptic ulcer was directly related to the low prevalence rate of duodenal ulcer. We hypothesize that the reason for these differences was probably a higher prevalence of Helicobacter pylori-associated chronic atrophic gastritis with hypochlorhydria in the Peruvian patients. Hypochlorhydria decreases the predisposition to peptic ulcer (especially duodenal ulcer), and chronic atrophic gastritis may predispose an individual to gastric cancer.     

Effect of dietary vitamin C on gastric cancer risk in the Korean population

AIM: To investigate the effects of dietary vitamin C and foods containing vitamin C on gastric cancer risk.METHODS: Our study included 830 control subjects and 415 patients. Data regarding demographics, medical history, and lifestyle, including dietary and nutrient intake, were collected using reliable selfadministered questionnaires. Dietary intake information was collected from the participants using a food frequency questionnaire that has been previously reported as reliable and valid. A rapid urease test and a histological evaluation were used to determine the presence of Helicobacter pylori(H. pylori) infection. Twenty-three vitamin C-contributing foods were selected, representing over 80% of the cumulative vitamin C contribution. RESULTS: In analyses adjusted for first-degree family history of gastric cancer, education level, job, household income, smoking status, and regular exercise, an inverseassociation between vitamin C intake and gastric cancer risk was observed for the highest(≥ 120.67 mg/d) vs the lowest( 80.14 mg/d) intake category [OR(95%CI): 0.64(0.46-0.88)], with a significant trend across the three intake categories(P = 0.007). No protective effect of vitamin C was detected after stratification by gender. No effect of vitamin C intake on the gastric cancer incidence was found in either men or women infected with H. pylori. Vitamin C-contributing foods, including cabbage [0.45(0.32-0.63), 0.50(0.34-0.75), 0.45(0.25-0.81)], strawberries [0.56(0.40-0.78), 0.49(0.32-0.74), 0.52(0.29-0.93)], and bananas [0.40(0.29-0.57), 0.41(0.27-0.62), 0.34(0.19-0.63)], were protective factors against the risk of gastric cancer based on the results of the overall adjusted analyses and the results for men and women, respectively.CONCLUSION: A protective effect of vitamin C and vitamin C-contributing foods against gastric cancer was observed. Further studies using larger sample sizes are required to replicate our results.     

Structural modifications of Helicobacter pylori lipopolysaccharide:An idea for how to live in peace

In this review,we discuss the findings and concepts underlying the"persistence mechanisms"of Helicobacter pylori(H.pylori),a spiral-shaped,Gram-negative rod bacterium that was discovered as a gastric pathogen by Marshall and Warren in 1984.H.pylori colonizes the gastric mucosa of nearly half of the human population.Infections appear in early childhood and,if not treated,persist for life.The presence or absence of symptoms and their severity depend on multiple bacterial components,host susceptibility and environmental factors,which allow H.pylori to switch between pathogenicity and commensalism.Many studies have shown that H.pylori components may facilitate the colonization process and the immune response of the host during the course of H.pylori infection.These H.pylori-driven interactions might result from positive or negative modulation.Among the negative immunomodulators,a prominent position is occupied by a vacuolating toxin A(VacA)and cytotoxin-associated gene A(CagA)protein.However,in light of the recent studies that are presented in this review,it is necessary to enrich this panel with H.pylori lipopolysaccharide(LPS).Together with CagA and VacA,LPS suppresses the elimination of H.pylori bacteria from the gastric mucosa by interfering with the activity of innate and adaptive immune cells,diminishing the inflammatory response,and affecting the adaptive T lymphocyte response,thus facilitating the development of chronic infections.The complex strategy of H.pylori bacteria for survival in the gastric mucosa of the host involves both structural modifications of LPS lipid A to diminish its endotoxic properties and the expression and variation of Lewis determinants,arranged in O-specific chains of H.pylori LPS.By mimicking host components,this phenomenon leaves these bacteria"invisible"to immune cells.Together,these mechanisms allow H.pylori to survive and live for many years within their hosts.