Mechanisms of Disease: Helicobacter pylori-related gastric carcinogenesis—implications for chemoprevention

Helicobacter pylori (H. pylori) Infection-Associated Dyslipidemia in the Asir Region of Saudi Arabia

OBJECTIVES

H. pylori-associated dyslipidemia has been reported to be a major risk factor for atherosclerosis and coronary heart diseases. We aimed to investigate the association of the H. pylori infection with dyslipidemia.

METHODS

A retrospective case-control study was undertaken to evaluate H. pylori-associated dyslipidemia, where H. pylori-positive individuals were treated as the case group (n = 260) while H. pylori-negative individuals were considered as the control group (n = 250). The mean ± SD of the age of the patients included (n = 510) was 44.01 ± 13.58 years. Study subjects with a total cholesterol level of >5.17 mmol/L and/or a triglyceride level of >1.69 mmol/L and/or an LDL-C level of >2.59 mmol/L and/or an HDL-C level of <1 mmol/L in males and/or an HDL-C level of <1.3 mmol/L in females were defined as dyslipidemia. Descriptive (mean, standard deviation, median, and IQR) and inferential (t-test, chi-square test, and logistic regression) statistical analyses were undertaken using the R-base/R-studio (v-4.0.2)/tidyverse package. Univariate and bivariate logistic regressions were executed to calculate the crude and adjusted odds ratio along with the p-value. A p-value of <0.05 was the cut-off for statistical significance. We used ggplot2 for data visualization.

RESULTS

The differences in overall mean ± SD (H. pylori positive vs. negative) of the cholesterol (5.22 ± 1.0 vs. 5.49 ± 0.85, p < 0.01), triglyceride (1.66 ± 0.75 vs. 1.29 ± 0.71, p < 0.001), LDL-C (3.43 ± 0.74 vs. 3.26 ± 0.81, p < 0.05), and HDL-C (1.15 ± 0.30 vs. 1.30 ± 0.25, p < 0.001) levels were statistically significant. The cholesterol and LDL-C levels in ages >60, age = 30-60, in females, and LDL-C levels in males were not significantly different for the H. pylori-positive and -negative groups. The proportion (H. pylori positive vs. negative) of hypercholesterolemia (190/59.9% vs. 127/40% p < 0.01), hypertriglyceridemia (136/68% vs. 64/32% p < 0.001), high LDL-cholesterolemia levels (234/53% vs. 201/46% p < 0.01), and low HDL-cholesterolemia levels (149/71% vs. 60/28.7% p < 0.01) were statistically significant. The odds of having hypercholesterolemia (AOR: 2.64, 95%CI: 1.824-3.848, p < 0.001), hypertriglyceridemia (AOR: 3.24, 95%CI: 2.227-4.757, p < 0.001), an increased LDL-C level (AOR: 2.174, 95%CI: 1.309-3.684, p < 0.01), and a decreased HDL-C level (AOR: 4.2, 95%CI: 2.937-6.321, p < 0.001) were 2.64, 3.24, 2.17, and 4.2 times higher in the H. pylori-infected individuals as compared with the H. pylori-uninfected group.

CONCLUSION

Our results demonstrate that an enhanced risk of dyslipidemia is associated with the H. pylori infection, which can aggrandize the atherosclerosis process. The evaluation of temporal variation in the lipid profile in H. pylori-infected individuals is recommended for the effective management of H. pylori-infected patients.

Helicobacter pylori (H. pylori) Infection-Associated Anemia in the Asir Region, Saudi Arabia

H. pylori (ubiquitous) and anemia together represent one of the growing health concerns globally. Gastroduodenal sequelae of H. pylori infection are distinguished; however, for the H. pylori infection and its implication in the development of anemia, iron has a significant health impact. We aimed to evaluate H. pylori infection-associated anemia by employing a logistic regression analysis model. A retrospective (case-control) study design-based assessment of the H. pylori associated-anemia. The study area was geo-referenced by QGIS/QuickMapServies. Descriptive and inferential statistical analyses were accomplished using the R-base-R-studio (v-4.0.2)-tidyverse. A p-value < 0.05 was the statistical significance cut-off value. A ggplot2 package was used for data representation and visualization. Mean ± SD age, Hb, MCV, ferritin, and RBC for overall study participants were measured to be 44.0 ± 13.58, 13.84 ± 2.49, 83.02 ± 8.31, 59.42 ± 68.37, and 5.14 ± 0.75, respectively. Decreased levels of Hb (infected vs. uninfected: 13.26 ± 2.92 vs. 14.42 ± 1.75, p < 0.001) ferritin (infected vs. uninfected: 48.11 ± 63.75 vs. 71.17 ± 71.14, p < 0.001), and MCV (infected vs. uninfected: 81.29 ± 9.13 vs. and 84.82 ± 6.93, p < 0.05) were measured to be associated with H. pylori infection when compared with H. pylori uninfected control group. Moreover, the magnitude (prevalence) of anemia (infected vs. uninfected: 78% vs. 21%, p < 0.001), iron deficiency anemia (IDA) (infected vs. uninfected: 63.3% vs. 36.6%, p < 0.001), and microcytic anemia (infected vs. uninfected: 71.6% vs. 46.1%, p < 0.001) were significantly different among the H. pylori-infected participants. The higher likelihood of developing anemia (AOR; 4.98, 95% CI; 3.089-8.308, p < 0.001), IDA (AOR; 3.061, 95% CI; 2.135-4.416, p < 0.001), and microcytic anemia (AOR; 3.289, 95% CI; 2.213-4.949, p < 0.001) by 398%, 206.1%, and 229%, respectively, was associated with H. pylori-infected. We recommend the regular monitoring of hematological parameters and eradication of H. pylori infection to minimize the extra-gastric health consequences of H. pylori infection.

Does Chemotherapy-Induced Gastrointestinal Mucositis Affect the Bioavailability and Efficacy of Anti-Infective Drugs?

Antimicrobial prophylaxis is increasingly being used in patients with hematological malignancies receiving high-dose chemotherapy and hematopoietic stem cell transplantation (HSCT). However, few studies have focused on the potential impact of gastrointestinal mucositis (GI-M), a frequently observed side effect of chemotherapy in patients with cancer that affects the gastrointestinal microenvironment, on drug absorption. In this review, we discuss how chemotherapy leads to an overall loss of mucosal surface area and consequently to uncontrolled transport across the barrier. The barrier function is depending on intestinal luminal pH, intestinal motility, and diet. Another factor contributing to drug absorption is the gut microbiota, as it modulates the bioavailability of orally administrated drugs by altering the gastrointestinal properties. To better understand the complex interplay of factors in GI-M and drug absorption we suggest: (i) the longitudinal characterization of the impact of GI-M severity on drug exposure in patients, (ii) the development of tools to predict drug absorption, and (iii) strategies that allow the support of the gut microbiota. These studies will provide relevant data to better design strategies to reduce the severity and impact of GI-M in patients with cancer.

Helicobacter pylori: Commensal, symbiont or pathogen?

This review considers the data on Helicobacter pylori (H. pylori), which have been accumulated over 40 years since its description as an etiological factor in gastrointestinal diseases. The majority of modern publications are devoted to the study of the pathogenic properties of the microorganism in the development of chronic gastritis, peptic ulcer disease, and gastric cancer, as well as methods for its eradication. However, in recent years, there have been more and more studies which have suggested that H. pylori has a beneficial, or potentially positive, effect on the human body. The authors have attempted to objectively analyze the information accumulated in the literature on H. pylori. Some studies consider it as one of the recently identified human bacterial pathogens, and special attention is paid to the evidence suggesting that it is probably part of the composition of the human microbiome as a commensal (commensal from French to English is a table companion) or even a symbiont. The presented data discussing the presence or absence of the effect of H. pylori on human health suggest that there is an apparent ambiguity of the problem. The re-assessment of the data available on H. pylori infection is important in order to answer the question of whether it is necessary to create a program of mass H. pylori eradication or to apply a more personalized approach to treating patients with H. pylori-associated gastrointestinal diseases and to perform eradication therapy.

Emerging trends in aggregation induced emissive luminogens as bacterial theranostics

The emergence and spread of pathogenic bacteria, particularly antibiotic-resistant strains pose grave global concerns worldwide, which demand for the rapid development of highly selective and sensitive strategies for specific bacterial detection, identification, imaging and therapy. The fascinating feature of aggregation-induced emissive molecules (AIEgens) to display fluorescence in aggregate form can be suitably coupled with nanotechnology for developing theranostic AIE dots that can offer convenient and customised functions such as sensing, imaging, detection, discrimination and cell kill of different bacterial types. The initial section of the article reveals the necessity for incorporating diagnostic imaging with antibacterial therapy, while the latter part delivers mechanistic insights on the benefits of AIE fluorophores in theranostic applications. Further, the review illustrates the recent advancements of AIEgens as theranostic nanolights in bacterial detection, identification and eradication. The review is organised according to the different classes of AIE-active bacterial theranostics such as carrier-free nanoprodrugs, nanomachines for synergistic imaging-guided cancer treatment and bacterial kill, AIE polymers, bioconjugates and nanoparticle carriers. By elucidating their design principles and applications, as well as highlighting the recent trends and perspectives that can be further explored, we hope to instill more research interest in AIE bacterial theranostics for future translational research.HighlightsCombination of aggregation induced emissive fluorophores and nanotechnology for developing bacterial theranostics.AIE theranostics with customised functions for bacterial imaging, detection, discrimination and cell kill.

The role of gut microbiota in cancer treatment: friend or foe?

The gut microbiota has been implicated in cancer and shown to modulate anticancer drug efficacy. Altered gut microbiota is associated with resistance to chemo drugs or immune checkpoint inhibitors (ICIs), whereas supplementation of distinct bacterial species restores responses to the anticancer drugs. Accumulating evidence has revealed the potential of modulating the gut microbiota to enhance the efficacy of anticancer drugs. Regardless of the valuable findings by preclinical models and clinical data of patients with cancer, a more thorough understanding of the interactions of the microbiota with cancer therapy helps researchers identify novel strategy for cancer prevention, stratify patients for more effective treatment and reduce treatment complication. In this review, we discuss the scientific evidence on the role of gut microbiota in cancer treatment, and highlight the latest knowledge and technologies leveraged to target specific bacteria that contribute to tumourigenesis. First, we provide an overview of the role of the gut microbiota in cancer, establishing the links between bacteria, inflammation and cancer treatment. Second, we highlight the mechanisms used by distinct bacterial species to modulate cancer growth, immune responses, as well as the efficacy of chemotherapeutic drugs and ICIs. Third, we demonstrate various approaches to modulate the gut microbiota and their potential in translational research. Finally, we discuss the limitations of current microbiome research in the context of cancer treatment, ongoing efforts to overcome these challenges and future perspectives.

Critical number of lymph node involvement in esophageal and gastric cancer and its impact on long-term survival-A single-center 8-year study

BACKGROUND

Nodal disease in esophageal and gastric cancer is associated with poor survival.

OBJECTIVES

To determine the critical level of lymph node involvement where survival becomes significantly compromised.

METHODS

Survival analyses using multivariable Cox regression and receiver operator characteristics (ROC) were undertaken to determine what number of positive lymph nodes were most sensitive and specific in predicting survival.

RESULTS

A total of 317 patients underwent esophagectomy (n = 190, 59.9%) and gastrectomy (n = 127, 40.1%) for adenocarcinoma. At multivariable analyses, four nodes positivity (irrespective of T-category) was associated with nearly a fivefold increased risk of mortality when compared to node-negative patients (hazard ratio [HR], 4.9; interquartile range 2.0-11.5; P < .001). A positive ratio of up to 50.0% was not associated with worse survival than having four nodes positive (HR, 4.6; 95% confidence interval, 2.6-8.1; P < .001). ROC analysis demonstrated four lymph nodes positive to have a sensitivity of 80.5%, a specificity of 60.1%, and an accuracy of 77.8 (P < .001).

CONCLUSION

The absolute number of nodes positive for cancer is more important than the proportion of positive nodes in predicting survival in esophageal/gastric cancer. Four positive lymph nodes are associated with a fivefold increase in mortality. Beyond this, increasing numbers of positive lymph nodes make no appreciable difference to survival.

Non-bismuth and bismuth quadruple therapies based on previous clarithromycin exposure are as effective and safe in an area of high clarithromycin resistance: A real-life study

BACKGROUND

Bismuth quadruple (BQT) and non-bismuth quadruple (N-BQT) therapies are the recommended first-line treatments for Helicobacter (H.) pylori infection.

OBJECTIVE

To compare the efficacy of BQT and N-BQT in clinical practice in an area with high clarithromycin resistance, choosing the regimen on the basis of previous exposure to clarithromycin.

METHODS

A total of 404 consecutive H pylori-positive, naïve patients were enrolled. A total of 203 patients without previous exposure to clarithromycin received N-BQT, 100 patients for 10 days and 103 for 14 days, whereas 201 with previous exposure to clarithromycin received 10-day BQT. Efficacy and treatment-related adverse events were assessed.

RESULTS AND CONCLUSIONS

Eradication rates by intention-to-treat analysis were 88.2% for N-BQT and 91.5% for BQT (P = .26); per-protocol analysis eradication rates were 91.2% and 95.8% for N-BQT and BQT, respectively (P = .07). Eradication rates were significantly higher with 14-day than 10-day CT (P < .003). Almost all patients had a good compliance with both N-BQT (95.6%) and BQT (95%). Adverse events occurred in 24.1% and 26.9% (P = .53) of patients in the N-BQT and BQT group, respectively. In conclusion, clarithromycin-containing non-bismuth or bismuth quadruple therapy, based on the knowledge of previous clarithromycin exposure, is effective and safe even in an area of high prevalence of clarithromycin-resistant H pylori strains.

Association between Active Helicobacter pylori Infection and Glaucoma: A Systematic Review and Meta-Analysis

Background: Glaucoma is the second most common cause of blindness worldwide affecting almost 70 million individuals. Helicobacter pylori (H. pylori) is a widespread pathogen with systematic pathogenicity. This meta-analysis aimed to estimate the contradictory data regarding a potential association between active H. pylori infection and glaucoma. Materials and Methods: A research in MEDLINE/PubMed and Google Scholar was conducted and original studies investigating the relationship between H. pylori infection and glaucoma were included. Analysis was performed with random effects model. The main outcome was the odds ratio (OR) with 95% confidence intervals (CI) of H. pylori infection as a risk factor for glaucoma. A parallel analysis studied the role of active infection as indicated by histology and the titer of anti-H. pylori antibodies. For the anti-H. pylori antibody titers, weighted mean differences (WMD) were estimated between patients and controls. Results: Fifteen studies were included, with 2664 participants (872 patients with glaucoma and 1792 controls), divided into primary open-angle glaucoma (POAG), normal tension glaucoma (NTG) and pseudo-exfoliation glaucoma (PEG). The association between H. pylori infection and overall glaucoma was significant (OR = 2.08, CI 95% 1.48–2.93) with moderate heterogeneity (I² = 61.54%). After stratification by glaucoma subtype, heterogeneity was eliminated in the NTG subgroup. Studies with healthy controls, and controls with anemia yielded very low or no heterogeneity, respectively. Gastric biopsy to document active H. pylori infection yielded the highest OR (5.4, CI: 3.17–9.2, p < 0.001) and null heterogeneity. For anti-H. pylori antibody titers, there was a significant difference in WMD between patients and controls (WMD 15.98 IU/mL; 95% CI: 4.09–27.87; p = 0.008); values were greater in glaucoma patients, with high heterogeneity (I²: 93.8%). Meta-regression analysis showed that mean age had a significant impact on glaucoma (p = 0.037). Conclusions: Active H. pylori infection may be associated with glaucoma with null heterogeneity, as, beyond histology, quantified by anti-H. pylori titers and increases with age.

Variations in cag pathogenicity island genes of Helicobacter pylori from Latin American groups may influence neoplastic progression to gastric cancer

Helicobacter pylori (HP) colonizes the human stomach and induces acute gastritis, peptic ulcer disease, atrophic gastritis, and gastric adenocarcinoma. Increased virulence in HP isolates derives from harboring the cag (cytotoxin-associated genes) pathogenicity island (cagPAI). We analyzed the microvariants in cagPAI genes with the hypothesis that they may play an important role in determining HP virulence. We tested DNAs from cagA positive patients HP isolates; a total of 74 patients with chronic gastritis (CG, N = 37), intestinal metaplasia (IM, N = 21) or gastric cancer (GC, N = 16) from Mexico and Colombia. We selected 520 non-synonymous variants with at least 7.5% frequency in the original sequence outputs or with a minimum of 5 isolates with minor allele. After adjustment for multiple comparisons, no variants were statistically significantly associated with IM or GC. However, 19 non-synonymous showed conventional P-values < 0.05 comparing the frequency of the alleles between the isolates from subjects with gastritis and isolates from subjects with IM or GC; 12 of these showed a significant correlation with the severity of the disease. The present study revealed that several cagPAI genes from Latin American Western HP strains contains a number of non-synonymous variants in relatively high frequencies which could influence on the clinical outcome. However, none of the associations remained statistically significant after adjustment for multiple comparison.

Reevaluation of the Efficacy of First Line Regimen for Helicobacter pylori

Background

Helicobacter pylori is a common cause of gastritis, peptic ulcer disease, and non-ulcer dyspepsia, and is also associated with gastric adenocarcinoma and mucosa associated lymphoid tissue lymphoma. Despite being known about for more than 30 years, finding an effective therapeutic strategy against it remains a challenge.

Aim

There are no US studies evaluating the efficacy of a Levofloxacin based therapy for H. pylori infection. We here intend to study the efficacy of Levofloxacin based triple antibiotic regimen as compared to Clarithromycin based triple therapy and Bismuth based quadruple therapy in our patient population.

Methods

This is a retrospective single center observational study. Patients with Helicobacter pylori infection who underwent treatment for H. pylori with one of the three therapies, i.e. Clarithromycin triple, Bismuth Quadruple or Levofloxacin triple, were included in the study and the eradication rates were compared. The confirmation of the H. pylori was done 4 weeks after the completion of anti-microbial therapy.

Results

A total of 177 individuals underwent the H. pylori treatment in our retrospective review. Of these, 54% (n=97) of patients were treated with Clarithromycin based triple therapy (Group 1), 35% (n=63) were treated with Levofloxacin based regimen (Group 2), and the remaining 11% (n=17) were treated with Bismuth based quadruple therapy (Group 3). The eradication rates were significantly higher in patients treated with Clarithromycin based triple therapy as compared to Levofloxacin based triple therapy and Bismuth quadruple therapy (78.3% vs 49.2% vs 41.1% P=0.001).

Conclusion

In conclusion, our study shows significantly lower eradication rates with Levofloxacin triple therapy among a selected US population. Thus, it may not be a good first-line therapy among this US population and the Clarithromycin based regimen may still be used successfully.

Genetic diversity and amino acid sequence polymorphism in Helicobacter pylori CagL hypervariable motif and its association with virulence markers and gastroduodenal diseases

Genetic variability in cagL gene especially within the Helicobacter pylori CagL hypervariable motif (CagLHM) may affect the development of gastric cancer. Therefore, this study was conducted to investigate the association of CagL diversity with clinical outcomes and with H pylori virulence markers. A total of 126 patients with different gastric diseases including non-ulcer dyspepsia (NUD), peptic ulcer disease (PUD), gastric erosion (GE), and gastric cancer (GC) were enrolled. H pylori was cultured from gastric biopsies, and the isolates were screened for the presence of cagL, cagA, vacA, babA2, sabA, and cagPAI integrity by PCR. The amino acid polymorphisms of cagL were analyzed using DNA sequencing. We isolated 61 (48.4%) H pylori strains from 36 NUD, eight PUD, 12 GE, and five GC patients. Almost all isolates were cagL positive (97%), and their RGD, RHS, and SKIIVK motifs were highly conserved. Among 10 CagLHM variants identified, NEIGQ and NKIGQ were detected as the most prevalent sequences. Interestingly, a significant association was found between the presence of NKMGK and PUD (P = 0.002). Notably, the NEIGQ isolates with multiple C-type EPIYA repeat that carried intact cagPAI correlated with disease risk for PUD, GE, and GC (P = 0.021). In conclusion, we identified novel variants of H pylori CagLHM sequences in Iranian population such as NKMGK, which was associated with disease risk for PUD. Further studies using a large number of strains are required to better clarify the function of certain CagLHM motifs in gastric carcinogenesis and disease outcome.

Peptide Hp(2-20) accelerates healing of TNBS-induced colitis in the rat

BACKGROUND AND AIMS

Hp(2-20), a Helicobacter pylori-derived peptide interacting with N-formyl peptide receptors (FPRs), accelerates the healing of gastric injury in rats. Whether Hp(2-20) affects the recovery of inflamed colonic mucosa is unknown. We evaluated whether Hp(2-20) accelerated the healing of 2,4,6-trinitrobenzenesulfonic acid (TNBS)-induced colitis and explored the mechanism(s) underlying any such effect.

METHODS

Fifteen rats underwent rectal administration of Hp(2-20) 250-500 µg/kg/day, or of its control peptide Hp1 for 10 days, following induction of colitis with TNBS. Macroscopic and histological damage was quantified using predetermined injury scores. FPR1, COX-2, TNF-α, TGF-β, HB-EGF and tissue transglutaminase (t-TG) messenger RNA (mRNA) expression in colonic tissue was determined by quantitative polymerase chain reaction; FPR1, TNF-α and COX-2 protein levels by Western blotting.

RESULTS

(1) Hp(2-20) accelerated healing of TNBS-induced colitis compared to controls consistently with the expression of FPRs in colonic mucosa; (2) TNBS upregulated mRNA mucosal expression of COX-2, TNF-α, TGF-β, HB-EGF and t-TG and (3) this, with the exception of HB-EGF, was significantly counteracted by Hp(2-20).

CONCLUSIONS

Hp(2-20), an FPR agonist, accelerates the healing of TNBS-induced colitis in the rat. This effect is associated with a significant reduction in colonic tissue levels of COX-2, TGF-β, TNF-α and t-TG. We postulate that FPR-dependent pathways may be involved in the repair of inflamed colonic mucosa.

Helicobacter pylori and extragastric diseases: A review

Helicobacter pylori (H. pylori) infection is very common and affects approximately half of the world population. It causes gastric diseases, but some authors have reported an association of H. pylori infection with other systemic manifestations beginning in 1994. The list of potential effects of H. pylori outside the stomach includes a number of extragastric manifestations and we focused on neurological, dermatological, hematologic, ocular, cardiovascular, metabolic, allergic, and hepatobiliary diseases. This review discusses these important reported manifestations that are not related to the gastrointestinal tract.

The effects of starter microbiota and the early life feeding of medium chain triglycerides on the gastric transcriptome profile of 2- or 3-week-old cesarean delivered piglets

Background

The stomach is an underestimated key interface between the ingesta and the digestive system, affecting the digestion and playing an important role in several endocrine functions. The quality of starter microbiota and the early life feeding of medium chain triglycerides may affect porcine gastric maturation. Two trials (T1, T2) were carried out on 12 and 24 cesarean-delivered piglets (birth, d0), divided over two microbiota treatments, but slaughtered and sampled at two or three weeks of age, respectively. All piglets were fed orally: sow serum (T1) or pasteurized sow colostrum (T2) on d0; simple starter microbiota (Lactobacillus amylovorus, Clostridium glycolicum and Parabacteroides spp.) (d1-d3); complex microbiota inoculum (sow diluted feces, CA) or a placebo (simple association, SA) (d3-d4) and milk replacer ad libitum (d0-d4). The The T1 piglets and half of the T2 piglets were then fed a moist diet (CTRL); the remaining half of the T2 piglets were fed the CTRL diet fortified with medium chain triglycerides and 7% coconut oil (MCT). Total mRNA from the oxyntic mucosa was analyzed using Affymetrix©Porcine Gene array strips. Exploratory functional analysis of the resulting values was carried out using Gene Set Enrichment Analysis.

Results

Complex microbiota upregulated 11 gene sets in piglets of each age group vs. SA. Of these sets, 6 were upregulated at both ages, including the set of gene markers of oxyntic mucosa. In comparison with the piglets receiving SA, the CA enriched the genes in the sets related to interferon response when the CTRL diet was given while the same sets were impoverished by CA with the MCT diet.

Conclusions

Early colonization with a complex starter microbiota promoted the functional maturation of the oxyntic mucosa in an age-dependent manner. The dietary fatty acid source may have affected the recruitment and the maturation of the immune cells, particularly when the piglets were early associated with a simplified starter microbiota.

Inflammatory and Apoptotic Regulatory Activity of Tanshinone IIA in Helicobacter pylori-Infected Cells

Helicobacter pylori infections induce host cell inflammation and apoptosis, however, they are conflicting. Tanshinone IIA is an active compound of Salvia miltiorrhiza Bge. In this study, we investigated the regulatory effects of tanshinone IIA on H. pylori-induced inflammation and apoptosis in vitro. Tanshinone IIA treatments (13.6-54.4[Formula: see text][Formula: see text]M) significantly decreased nuclear factor kappa B (NF-kB) and mitogen-activated protein kinase (MAPK) [p-38 and C-terminal Jun-kinase 1/2 (JNK1/2)] protein expressions and inflammatory substance [cyclooxygenase-2 (COX-2), 5-lipooxygenase (5-LOX), intercellular adhesion molecule-1 (ICAM-1), reactive oxygen species (ROS), nitric oxide (NO), inducible nitric oxide synthase (iNOS), interleukin-1[Formula: see text] (IL-1[Formula: see text], IL-6, and IL-8] production in the H. pylori-infected cells. In contrast, tanshinone IIA treatments significantly increased apoptotic relevant protein [Bcl-2-associated X protein (Bax) and caspase 9] expressions and increased mitochondrial transmembrane potential ([Formula: see text] disruption, mitochondrial cytochrome [Formula: see text] (cyt [Formula: see text] release, and caspase cascades. Tanshinone IIA treatments effectively decreased H. pylori-induced inflammation and significantly promoted H. pylori-induced intrinsic apoptosis through NF-kB and MAPK (p-38 and JNK) pathways. Tanshinone IIA has great potential as a candidate to protect host cells from H. pylori-induced severe inflammation and gastric cancer.

Pharmacokinetics and Safety of Triple Therapy with Vonoprazan, Amoxicillin, and Clarithromycin or Metronidazole: A Phase 1, Open-Label, Randomized, Crossover Study

INTRODUCTION

Vonoprazan (TAK-438) is a novel potassium-competitive acid blocker that inhibits gastric H(+), K(+)-ATPase. The objectives of this study were to evaluate the influence of triple therapy with vonoprazan-amoxicillin-clarithromycin or vonoprazan-amoxicillin-metronidazole on the pharmacokinetics of each component of the triple therapies (primary) and to evaluate the safety and tolerability of vonoprazan-based triple therapies (secondary) in healthy adults.

METHODS

In this single-center, phase 1, open-label, randomized, four-way crossover study, Helicobacter pylori-negative, healthy Japanese male subjects were randomly assigned to 1 of 4 treatment sequences in two cohorts (12 subjects per cohort). Each treatment sequence comprised four treatment periods separated by a washout period of 7 or 14 days. Pharmacokinetic parameters for vonoprazan, amoxicillin, clarithromycin and metronidazole in single therapy or triple therapies were assessed. All adverse events were recorded.

RESULTS

Compared with single therapy, triple therapy with vonoprazan-amoxicillin-clarithromycin increased the area under the plasma concentration-time curve from time 0-12 h (AUC0-12) and maximum plasma concentration (C max) of plasma vonoprazan free base by 1.846- and 1.868-fold, respectively, and increased the AUC0-12 and C max of plasma clarithromycin by 1.450- and 1.635-fold, respectively. Triple therapy with vonoprazan-amoxicillin-metronidazole had no influence on the pharmacokinetics of vonoprazan or metronidazole. The pharmacokinetics of amoxicillin was not influenced by vonoprazan-based triple therapies. Seven adverse events were reported. Two subjects discontinued because of an adverse event (rash, liver function test abnormal); both events were considered to be study drug-related.

CONCLUSION

In healthy Japanese male subjects, triple therapy with vonoprazan-amoxicillin-clarithromycin increased vonoprazan and clarithromycin exposure. The safety and tolerability profile of triple therapy with vonoprazan-amoxicillin-clarithromycin or vonoprazan-amoxicillin-metronidazole was favorable in this population.

FUNDING

Takeda Pharmaceutical Company Ltd.

TRIAL REGISTRATION

JapicCTI-153102.

Relationship between VacA Toxin and Host Cell Autophagy in Helicobacter pylori Infection of the Human Stomach: A Few Answers, Many Questions

Helicobacter pylori is a Gram-negative bacterium that colonizes the stomach of about half the global population and represents the greatest risk factor for gastric malignancy. The relevance of H. pylori for gastric cancer development is equivalent to that of tobacco smoking for lung cancer. VacA toxin seems to play a pivotal role in the overall strategy of H. pylori towards achieving persistent gastric colonization. This strategy appears to involve the modulation of host cell autophagy. After an overview of autophagy and its role in infection and carcinogenesis, I critically review current knowledge about the action of VacA on host cell autophagy during H. pylori infection of the human stomach. Although VacA is a key player in modulation of H. pylori-induced autophagy, a few discrepancies in the data are also evident and many questions remain to be answered. We are thus still far from a definitive understanding of the molecular mechanisms through which VacA affects autophagy and the consequences of this toxin action on the overall pathogenic activity of H. pylori.

Anti-Inflammatory Effects of Capsaicin and Piperine on Helicobacter pylori-Induced Chronic Gastritis in Mongolian Gerbils

BACKGROUND

Spices have been used for thousands of years, and recent studies suggest that certain spices confer beneficial effects on gastric disorders. The purpose of this study was to evaluate possible chemopreventive effects of spice-derived compounds on Helicobacter pylori (H. pylori)-induced gastritis.

METHODS

We examined the inhibitory effects of curcumin, capsaicin, and piperine on H. pylori in vitro by determining the colony-forming units and real-time RT-PCR in H. pylori stimulated AGS gastric cancer cells. For in vivo analysis, 6-week-old SPF male Mongolian gerbils were infected with H. pylori, fed diets containing 5000 ppm curcumin, 100 ppm capsaicin, or 100 ppm piperine, and sacrificed after 13 weeks.

RESULTS

All three compounds inhibited in vitro proliferation of H. pylori, with curcumin being the most effective. Infiltration of neutrophils and mononuclear cells was suppressed by piperine both in the antrum and corpus of H. pylori-infected gerbils. Capsaicin also decreased neutrophils in the antrum and corpus and mononuclear cell infiltration and heterotopic proliferative glands in the corpus. mRNA expression of Tnf-α and formation of phospho-IκB-α in the antrum were reduced by both capsaicin and piperine. In addition, piperine suppressed expression of Il-1β, Ifn-γ, Il-6, and iNos, while H. pylori UreA and other virulence factors were not significantly attenuated by any compounds.

CONCLUSION

These results suggest that capsaicin and piperine have anti-inflammatory effects on H. pylori-induced gastritis in gerbils independent of direct antibacterial effects and may thus have potential for use in the chemoprevention of H. pylori-associated gastric carcinogenesis.

Helicobacter pylori infection but not small intestinal bacterial overgrowth may play a pathogenic role in rosacea

BACKGROUND AND AIMS

Recent studies suggest a potential relationship between rosacea and Helicobacter pylori (H. pylori) infection or small intestinal bacterial overgrowth (SIBO), but there is no firm evidence of an association between rosacea and H. pylori infection or SIBO. We performed a prospective study to assess the prevalence of H. pylori infection and/or SIBO in patients with rosacea and evaluated the effect of H. pylori or SIBO eradication on rosacea.

METHODS

We enrolled 90 patients with rosacea from January 2012 to January 2013 and a control group consisting of 90 patients referred to us because of mapping of nevi during the same period. We used the (13)C Urea Breath Test and H. pylori stool antigen (HpSA) test to assess H. pylori infection and the glucose breath test to assess SIBO. Patients infected by H. pylori were treated with clarithromycin-containing sequential therapy. Patients positive for SIBO were treated with rifaximin.

RESULTS

We found that 44/90 (48.9%) patients with rosacea and 24/90 (26.7%) control subjects were infected with H. pylori (p = 0.003). Moreover, 9/90 (10%) patients with rosacea and 7/90 (7.8%) subjects in the control group had SIBO (p = 0.6). Within 10 weeks from the end of antibiotic therapy, the skin lesions of rosacea disappeared or decreased markedly in 35/36 (97.2%) patients after eradication of H. pylori and in 3/8 (37.5%) patients who did not eradicate the infection (p < 0.0001). Rosacea skin lesions decreased markedly in 6/7 (85.7%) after eradication of SIBO whereas of the two patients who did not eradicate SIBO, one (50%) showed an improvement in rosacea (p = 0.284).

CONCLUSIONS

Prevalence of H. pylori infection was significantly higher in patients with rosacea than control group, whereas SIBO prevalence was comparable between the two groups. Eradication of H. pylori infection led to a significant improvement of skin symptoms in rosacea patients.

Probiotics against neoplastic transformation of gastric mucosa: Effects on cell proliferation and polyamine metabolism

Gastric cancer is still the second leading cause of cancer death worldwide, accounting for about 10% of newly diagnosed neoplasms. In the last decades, an emerging role has been attributed to the relations between the intestinal microbiota and the onset of both gastrointestinal and non-gastrointestinal neoplasms. Thus, exogenous microbial administration of peculiar bacterial strains (probiotics) has been suggested as having a profound influence on multiple processes associated with a change in cancer risk. The internationally accepted definition of probiotics is live microorganisms that, when administered in adequate amounts, confer a health benefit on the host. The possible effects on the gastrointestinal tract following probiotic administration have been investigated in vitro and in animal models, as well as in healthy volunteers and in patients suffering from different human gastrointestinal diseases. Although several evidences are available on the use of probiotics against the carcinogen Helicobacter pylori, little is still known about the potential cross-interactions among probiotics, the composition and quality of intestinal flora and the neoplastic transformation of gastric mucosa. In this connection, a significant role in cell proliferation is played by polyamines (putrescine, spermidine, and spermine). These small amines are required in both pre-neoplastic and neoplastic tissue to sustain the cell growth and the evidences here provided suggest that probiotics may act as antineoplastic agents in the stomach by affecting also the polyamine content and functions. This review will summarize data on the most widely recognized effects of probiotics against neoplastic transformation of gastric mucosa and in particular on their ability in modulating cell proliferation, paying attention to the polyamine metabolism.

Use of larvae of the wax moth Galleria mellonella as an in vivo model to study the virulence of Helicobacter pylori

Background

Helicobacter pylori is the first bacterium formally recognized as a carcinogen and is one of the most successful human pathogens, as over half of the world’s population is colonized by the bacterium. H. pylori-induced gastroduodenal disease depends on the inflammatory response of the host and on the production of specific bacterial virulence factors. The study of Helicobacter pylori pathogenic action would greatly benefit by easy-to-use models of infection.

Results

In the present study, we examined the effectiveness of the larvae of the wax moth Galleria mellonella as a new model for H. pylori infection. G. mellonella larvae were inoculated with bacterial suspensions or broth culture filtrates from either different wild-type H. pylori strains or their mutants defective in specific virulence determinants, such as VacA, CagA, CagE, the whole pathogenicity island (PAI) cag, urease, and gamma-glutamyl transpeptidase (GGT). We also tested purified VacA cytotoxin. Survival curves were plotted using the Kaplan-Meier method and LD₅₀ lethal doses were calculated. Viable bacteria in the hemocoel were counted at different time points post-infection, while apoptosis in larval hemocytes was evaluated by annexin V staining. We found that wild-type and mutant H. pylori strains were able to survive and replicate in G. mellonella larvae which underwent death rapidly after infection. H. pylori mutant strains defective in either VacA, or CagA, or CagE, or cag PAI, or urease, but not GGT-defective mutants, were less virulent than the respective parental strain. Broth culture filtrates from wild-type strains G27 and 60190 and their mutants replicated the effects observed using their respective bacterial suspension. Also, purified VacA cytotoxin was able to kill the larvae. The killing of larvae always correlated with the induction of apoptosis in hemocytes.

Conclusions

G. mellonella larvae are susceptible to H. pylori infection and may represent an easy to use in vivo model to identify virulence factors and pathogenic mechanisms of H. pylori. The experimental model described can be useful to screen a large number of clinical H. pylori strain and to correlate virulence of H. pylori strains with patients’ disease status.

Eradication of Helicobacter pylori infection: Which regimen first?

Helicobacter pylori (H. pylori) is a well-known human pathogen that plays an essential role in the pathogenesis of chronic gastritis, peptic ulcer disease, and gastric malignancies. Although H. pylori is susceptible to several antimicrobials, this infection has proven challenging to cure because of the increasing prevalence of bacterial strains that are resistant to the most commonly used antimicrobials, particularly clarithromycin. An effective (i.e., > 90%) first-line therapy is mandatory for avoiding supplementary treatments and testing, and more importantly for preventing the development of secondary resistance. This study reviews the recent literature on first-line therapies for H. pylori. The eradication rates following standard triple therapy (a proton pump inhibitor plus amoxicillin and clarithromycin) for H. pylori infection are declining worldwide. Several first-line strategies have been proposed to increase the eradication rate, including extending the treatment duration to 14 d, the use of a four-drug regimen (bismuth-containing quadruple, sequential, and concomitant treatments), and the use of novel antibiotics, such as fluoroquinolones. However, the efficacy of these regimens is controversial. A first-line eradication regimen should be based on what works best in a defined geographical area and must take into account the prevalence of antimicrobial resistance in that region.

Helicobacter pylori gamma-glutamyl transpeptidase and its pathogenic role

Helicobacter pylori (H. pylori) gamma-glutamyl transpeptidase (GGT) is a bacterial virulence factor that converts glutamine into glutamate and ammonia, and converts glutathione into glutamate and cysteinylglycine. H. pylori GGT causes glutamine and glutathione consumption in the host cells, ammonia production and reactive oxygen species generation. These products induce cell-cycle arrest, apoptosis, and necrosis in gastric epithelial cells. H. pylori GGT may also inhibit apoptosis and induce gastric epithelial cell proliferation through the induction of cyclooxygenase-2, epidermal growth factor-related peptides, inducible nitric oxide synthase and interleukin-8. H. pylori GGT induces immune tolerance through the inhibition of T cell-mediated immunity and dendritic cell differentiation. The effect of GGT on H. pylori colonization and gastric persistence are also discussed.

Intestinal microbiota, probiotics and human gastrointestinal cancers

INTRODUCTION

Cancers of the gastrointestinal tract account for 25 % of all cancers and for 9 % of all causes of cancer death in the world, so gastrointestinal cancers represent a major health problem. In the past decades, an emerging role has been attributed to the interactions between the gastrointestinal content and the onset of neoplasia.

METHODS

Thus, exogenous microbial administration of peculiar bacterial strains (probiotics) has been suggested as having a profound influence on multiple processes associated with a change in cancer risk. Probiotics are mono or mixed cultures of live microorganisms that might beneficially affect the host by improving the characteristics of indigenous microflora. Although the effects of probiotic administration has been intensively investigated in vitro, in animal models, in healthy volunteers, and in some human gastrointestinal diseases, very little is still known about the possible cross-interactions among probiotic administration, changes of intestinal flora, and the neoplastic transformation of gastrointestinal mucosa.

RESULTS

Theoretically, probiotics are able to reduce cancer risk by a number of mechanisms: (a) binding and degradation of potential carcinogens; (b) quantitative, qualitative and metabolic alterations of the intestinal microflora; (c) production of anti-tumorigenic or anti-mutagenic compounds; (d) competitive action towards pathogenic bacteria; (e) enhancement of the host's immune response; (f) direct effects on cell proliferation.

CONCLUSION

This review will attempt to highlight the literature on the most widely recognized effects of probiotics against neoplastic transformation of gastrointestinal mucosa and in particular on their effects on cell proliferation.

Intoxication strategy of Helicobacter pylori VacA toxin

VacA toxin from the cancer-inducing bacterium Helicobacter pylori is currently classified as a pore-forming toxin but is also considered a multifunctional toxin, apparently causing many pleiotropic cell effects. However, an increasing body of evidence suggests that VacA could be the prototype of a new class of monofunctional A-B toxins in which the A subunit exhibits pore-forming instead of enzymatic activity. Thus, VacA may use a peculiar mechanism of action, allowing it to intoxicate the human stomach. By combining the action of a cell-binding domain, a specific intracellular trafficking pathway and a novel mitochondrion-targeting sequence, the VacA pore-forming domain is selectively delivered to the inner mitochondrial membrane to efficiently kill target epithelial cells by apoptosis.

Variations in Helicobacter pylori cytotoxin-associated genes and their influence in progression to gastric cancer: implications for prevention

Helicobacter pylori (HP) is a bacterium that colonizes the human stomach and can establish a long-term infection of the gastric mucosa. Persistent Hp infection often induces gastritis and is associated with the development of peptic ulcer disease, atrophic gastritis, and gastric adenocarcinoma. Virulent HP isolates harbor the cag (cytotoxin-associated genes) pathogenicity island (cagPAI), a 40 kb stretch of DNA that encodes components of a type IV secretion system (T4SS). This T4SS forms a pilus for the injection of virulence factors into host target cells, such as the CagA oncoprotein. We analyzed the genetic variability in cagA and other selected genes of the HP cagPAI (cagC, cagE, cagL, cagT, cagV and cag Gamma) using DNA extracted from frozen gastric biopsies or from clinical isolates. Study subjects were 95 cagA+ patients that were histologically diagnosed with chronic gastritis or gastric cancer in Venezuela and Mexico, areas with high prevalence of Hp infection. Sequencing reactions were carried out by both Sanger and next-generation pyrosequencing (454 Roche) methods. We found a total of 381 variants with unambiguous calls observed in at least 10% of the originally tested samples and reference strains. We compared the frequencies of these genetic variants between gastric cancer and chronic gastritis cases. Twenty-six SNPs (11 non-synonymous and 14 synonymous) showed statistically significant differences (P<0.05), and two SNPs, in position 1039 and 1041 of cagE, showed a highly significant association with cancer (p-value = 2.07×10⁻⁶), and the variant codon was located in the VirB3 homology domain of Agrobacterium. The results of this study may provide preliminary information to target antibiotic treatment to high-risk individuals, if effects of these variants are confirmed in further investigations.

Molecular cross-talk between Helicobacter pylori and human gastric mucosa

Helicobacter pylori (H. pylori) has co-evolved with humans to be transmitted from person to person and to colonize the stomach persistently. A well-choreographed equilibrium between the bacterial effectors and host responses permits microbial persistence and health of the host, but confers a risk for serious diseases including gastric cancer. During its long coexistence with humans, H. pylori has developed complex strategies to limit the degree and extent of gastric mucosal damage and inflammation, as well as immune effector activity. The present editorial thus aims to introduce and comment on major advances in the rapidly developing area of H. pylori/human gastric mucosa interaction (and its pathological sequelae), which is the result of millennia of co-evolution of, and thus of reciprocal knowledge between, the pathogen and its human host.

Helicobacter pylori gamma-glutamyltranspeptidase induces cell cycle arrest at the G1-S phase transition

In our previous study, we showed that Helicobacter pylori gamma-glutamyltranspeptidase (GGT) is associated with H. pylori-induced apoptosis through a mitochondrial pathway. To better understand the role of GGT in apoptosis, we examined the effect of GGT on cell cycle regulation in AGS cells. To determine the effect of recombinant GGT (rGGT) on cell cycle distribution and apoptosis, rGGT-treated and untreated AGS cells were analyzed in parallel by flow cytometry using propidium iodide (PI). We found that rGGT inhibited the growth of AGS cells in a time-dependent manner, and that the pre-exposure of cells to a caspase-3 inhibitor (z-DEVD-fmk) effectively blocked GGT-induced apoptosis. Cell cycle analysis showed G1 phase arrest and apoptosis in AGS cells following rGGT treatment. The rGGT-mediated G1 phase arrest was found to be associated with down-regulation of cyclin E, cyclin A, Cdk 4, and Cdk 6, and the up-regulation of the cyclin-dependent kinase (Cdk) inhibitors p27 and p21. Our results suggest that H. pylori GGT induces cell cycle arrest at the G1-S phase transition.

Helicobacter pylori gamma-glutamyltranspeptidase induces cell cycle arrest at the G1-S phase transition

In our previous study, we showed that Helicobacter pylori gamma-glutamyltranspeptidase (GGT) is associated with H. pylori-induced apoptosis through a mitochondrial pathway. To better understand the role of GGT in apoptosis, we examined the effect of GGT on cell cycle regulation in AGS cells. To determine the effect of recombinant GGT (rGGT) on cell cycle distribution and apoptosis, rGGT-treated and untreated AGS cells were analyzed in parallel by flow cytometry using propidium iodide (PI). We found that rGGT inhibited the growth of AGS cells in a time-dependent manner, and that the pre-exposure of cells to a caspase-3 inhibitor (z-DEVD-fmk) effectively blocked GGT-induced apoptosis. Cell cycle analysis showed G1 phase arrest and apoptosis in AGS cells following rGGT treatment. The rGGT-mediated G1 phase arrest was found to be associated with down-regulation of cyclin E, cyclin A, Cdk 4, and Cdk 6, and the up-regulation of the cyclin-dependent kinase (Cdk) inhibitors p27 and p21. Our results suggest that H. pylori GGT induces cell cycle arrest at the G1-S phase transition.

Genetic predisposition to gastro-oesophageal cancer

Gastro-oesophageal cancers were ranked as the second cause of death from cancer worldwide despite a steady decrease in incidence for squamous cell carcinoma (SCC) of the oesophagus and distal gastric cancers. Adenocarcinoma of the oesophagus (OAC) is the tumour whose incidence has seen the highest increase in the past 30 years. Most of these cancers are strongly associated with environmental and life style risk factors such as smoking and alcohol for SCC, gastro-oesophageal reflux for OAC and Helicobacter pylori for distal gastric cancer. It may therefore be unsurprising that SCC is associated with polymorphisms in ALDH2 and ADH1B1, enzyme involved in alcohol metabolism, and with CYP1A1, involved in xenobiotics detoxification. OAC, whose incidence in absolute terms remains low, has been much less studied and at best the associations identified with risk are weak. Diffuse type gastric cancers while relatively uncommon have a strong genetic association with mutation of the CDH1 gene and prostate specific cancer antigen (PSCA) was demonstrated in a GWAS to be associated with an increased risk of diffuse gastric cancer but not intestinal type gastric cancer. This family of cancer is more associated with polymorphisms at the IL-1beta, IL-1RN loci and MHTFR loci. Specific strains of H pylori containing the virulence factors VacA s1, VacA m1 and cag A together with polymorphism at the IL-1beta and IL-1RN loci have up to a 87-fold increase in risk for developing intestinal type gastric cancer. While progress has been made to identify genetic variants associated with upper-gastrointestinal cancers, the relative small prevalence for some subtypes underlies the need for consortia, especially in view of the large variations in the prevalence of polymorphisms between different populations.

Intuitive eating: a holistic approach to weight control

As obesity rates continue to rise, it is clear that more holistic and homeostasis-friendly alternatives to dieting are needed. Dieting and restraint disrupt homeostasis and cause physical, emotional, and spiritual distress. Intuitive eating is an alternative that focuses on body's internal cues of hunger and fullness to guide how much to eat.

Three-dimensional structure of N-terminal domain of DnaB helicase and helicase-primase interactions in Helicobacter pylori

Replication initiation is a crucial step in genome duplication and homohexameric DnaB helicase plays a central role in the replication initiation process by unwinding the duplex DNA and interacting with several other proteins during the process of replication. N-terminal domain of DnaB is critical for helicase activity and for DnaG primase interactions. We present here the crystal structure of the N-terminal domain (NTD) of H. pylori DnaB (HpDnaB) helicase at 2.2 A resolution and compare the structural differences among helicases and correlate with the functional differences. The structural details of NTD suggest that the linker region between NTD and C-terminal helicase domain plays a vital role in accurate assembly of NTD dimers. The sequence analysis of the linker regions from several helicases reveals that they should form four helix bundles. We also report the characterization of H. pylori DnaG primase and study the helicase-primase interactions, where HpDnaG primase stimulates DNA unwinding activity of HpDnaB suggesting presence of helicase-primase cohort at the replication fork. The protein-protein interaction study of C-terminal domain of primase and different deletion constructs of helicase suggests that linker is essential for proper conformation of NTD to interact strongly with HpDnaG. The surface charge distribution on the primase binding surface of NTDs of various helicases suggests that DnaB-DnaG interaction and stability of the complex is most probably charge dependent. Structure of the linker and helicase-primase interactions indicate that HpDnaB differs greatly from E.coli DnaB despite both belong to gram negative bacteria.

Methylation of PTCH1a gene in a subset of gastric cancers

AIM: To establish if PTCH1a transcriptional regulation region (TRR) is methylated in gastric cancer and its influence in gastric tumorigenesis.

METHODS: The CpG islands in PTCH1a TRR were analyzed by Methyl Primer Express v1.0 software. The region from -643 to -355 bp (the transcription initiation site of PTCH1a was designated as 0) that contained 19 CpG sites was chosen for bisulfite-sequencing PCR (BSP) and methylation-specific PCR (MSP) detection. The gastric cancer cell line AGS was treated with 5-aza-2’-deoxycytidine (5-Aza-dC; 1 μmol/L) for 3 d. Alterations in PTCH1a TRR methylation in treated AGS cells was measured through BSP clone sequences, and their PTCH1 expression was measured by quantitative RT-PCR. The cell cycle and apoptosis were observed with flow cytometry through propidium iodide (PI) staining or annexin V/PI double staining. The prevalence of PTCH1a TRR methylation was investigated in 170 gastric cancer tissue samples and the adjacent normal tissues by MSP. The correlation of PTCH1a TRR methylation with PTCH1 expression or with patients’ clinical features was analyzed.

RESULTS: Methylation of PTCH1a TRR was observed in AGS cells and a subset of gastric cancer tissues (32%, 55/170), while no methylation amplification products were observed in any normal tissues by MSP. The methylation of PTCH1a TRR was correlated negatively with PTCH1 expression (Spearman’s r = -0.380, P = 0.000). However, methylation of PTCH1a TRR was not related to the gastric cancer patients’ clinical features, such as sex, age of onset, clinical stage, lymph node metastasis or histological grade. The methylation of PTCH1a TRR in AGS cells was almost converted to non-methylation after 5-Aza-dC treatment, which increased PTCH1 expression (5.3 ± 2.5 times; n = 3) and apoptosis rate (3.0 ± 0.26 times; P < 0.05; n = 3).

CONCLUSION: Methylation of PTCH1a TRR is present in a subset of gastric cancers and correlated negatively with PTCH1 expression. This may be an early event in gastric tumorigenesis and a new treatment target.

Helicobacter pylori protein HP0175 transactivates epidermal growth factor receptor through TLR4 in gastric epithelial cells

The pathophysiology of Helicobacter pylori-associated gastroduodenal diseases, ulcerogenesis, and carcinogenesis is intimately linked to activation of epidermal growth factor receptor (EGFR) and production of vascular endothelial growth factor (VEGF). Extracellular virulence factors, such as CagA and VacA, have been proposed to regulate EGFR activation and VEGF production in gastric epithelial cells. We demonstrate that the H. pylori secretory protein, HP0175, by virtue of its ability to bind TLR4, transactivates EGFR and stimulates EGFR-dependent VEGF production in the gastric cancer cell line AGS. Knock-out of the hp0175 gene attenuates the ability of the resultant H. pylori strain to activate EGFR or to induce VEGF production. HP0175-induced activation of EGFR is preceded by translocation of TLR4 into lipid rafts. In lipid rafts, the Src kinase family member Lyn interacts with TLR4, leading to tyrosine phosphorylation of TLR4. Knockdown of Lyn prevents HP0175-induced activation of EGFR and VEGF production. Tyrosine-phosphorylated TLR4 interacts with EGFR. This interaction is necessary for the activation of EGFR. Disruption of lipid rafts with methyl beta-cyclodextrin prevents HP0175-induced tyrosine phosphorylation of TLR4 and activation of EGFR. This mechanism of transactivation of EGFR is novel and distinct from that of metalloprotease-dependent shedding of EGF-like ligands, leading to autocrine activation of EGFR. It provides new insight into our understanding of the receptor cross-talk network.

Failure of first-line eradication treatment significantly increases prevalence of antimicrobial-resistant Helicobacter pylori clinical isolates

OBJECTIVES

Helicobacter pylori infection is a major health problem worldwide, and effective eradication of the infection is mandatory. The efficacy of recommended eradication regimens is approximately 70%. To avoid treatment failure and the consequent development of secondary resistance(s), it is important to choose the most appropriate first-line treatment regimen. This choice should also be made based on the knowledge of the antimicrobial resistance peculiar to a given geographical area. We evaluated the prevalence of antimicrobial-resistant H pylori strains isolated from naive patients and from patients with previous unsuccessful treatments.

METHODS

This study examined 109 H pylori-infected subjects (Group 1) who had never received an eradication treatment and 104 H pylori-infected subjects (Group 2) who had failed one or more eradication treatments. Resistance to amoxicillin (AMO), tetracycline (TET), clarithromycin (CLA), metronidazole (MET) and levofloxacin (LEV) was determined using the epsilometer test. The significance of differences was evaluated by the chi2 test.

RESULTS

The prevalence of antimicrobial resistance was 0% versus 3.1% to AMO, 0% versus 2% to TET, 27% versus 41.3% to MET (p<0.05), 18% versus 45.8% to CLA (p<0.05) and 3% versus 14.6% to LEV (p<0.05) in Group 1 vs Group 2, respectively. In Group 2, there was an increased prevalence of H pylori strains resistant to multiple antimicrobials.

CONCLUSIONS

This study confirms the high prevalence of H pylori strains resistant to CLA and MET, and indicates that unsuccessful treatments significantly increase resistance. Choosing eradication regimens other than standard triple therapy as a first-line therapy should be advisable in areas with high primary antimicrobial resistance prevalence.

New Aspects of Helicobacter pylori Infection Involvement in Gastric Oncogenesis

Gastric adenocarcinoma not located in the cardia still remains second only to lung cancer as the leading cause of cancer-related mortality worldwide, whereas adenocarcinoma of the cardia and gastroesophageal junction has been rapidly rising over the past two decades. Gastric malignancy can be subdivided into diffuse and intestinal pathologic entities that have different epidemiological and prognostic features. Various genetic and environmental factors lead to either abnormal gene overexpression or inappropriate expression of normal genes, whose products confer the malignant phenotype. Advances have been made in genetic changes mostly of the intestinal type; its development is probably a multistep process, as has been well described in colon carcinogenesis. Oncogene overexpression, tumor suppressor loss, and defective DNA mismatch repair is associated with gastric cancer. The most common genetic abnormalities tend to be loss of heterozygosity of particularly tumor suppressor p53 gene or "adenomatous polyposis coli" gene. The latter leads to gastric carcinogenesis through changes related to E-cadherin-catenin complex, which plays a critical role in normal tissue architecture maintenance. Mutation of any of its components results in loss of cell-cell adhesion, thereby contributing to malignancy. Putative trophic factors have also been involved in gastric oncogenesis. E-cadherin/CDH1 gene germline mutations have been recognized in families with an inherited predisposition to diffuse-type malignancy. This review focuses mainly on Helicobacter pylori infection involved in gastric carcinogenesis through various mechanisms, including repopulation of the stomach with bone marrow-derived stem cells that may facilitate gastric cancer progression, thereby necessitating eradication of this bacterium.

Differential regulation of ERK1/2 and p38 MAP kinases in VacA-induced apoptosis of gastric epithelial cells

Helicobacter pylori vacuolating cytotoxin A (VacA) has been considered as an apoptosis-inducing factor. Here, we investigated the mechanism of VacA-induced apoptosis in relation to the defense mechanism and MAP kinases pathway in gastric epithelial cells. AGS cells exposed to enriched VacA extracts affected the level of SOD-1 and villin. We further investigated the role of VacA in those inductions using a functional recombinant VacA (rVacA). Activation of p38 MAPK and Bax dimerization by rVacA were increased in a dose-dependent manner. rVacA-induced ERK1/2 MAPK activation was maximal at 30 min and 4 h and 1-4 microg/ml of rVacA. rVacA-induced SOD-1 expression was considerably diminished by inhibiting ERK1/2 MAPK and it was slightly increased by inhibiting p38 MAPK. rVacA increased or decreased villin expression depending on dose and exposure time and its expression was mainly appeared in the contractile actin ring of the dividing cells. Despite its cytoprotective effect, SB-203580, a p38 inhibitor, was unlikely to reduce VacA-induced Bax dimerization and rather inhibited villin and Bcl2 expression, indicating that p38 may also play a role in cell proliferation or differentiation for survival after VacA intoxication. Furthermore, p38 inhibitor accelerated rVacA-induced cell death after exposure of AGS cells to H(2)O(2) but ERK1/2 inhibitor protected cells from H(2)O(2) insult. These results suggest that SOD-1 and villin are expressed differentially upon VacA insult depending on dose and exposure time via ERK and p38 MAP kinases; decrease in SOD-1 and villin expression coupled with Bax dimerization leads to apoptosis of gastric epithelial cells.

Adenoviral gene therapy in gastric cancer: A review

Gastric cancer is one of the most common malignancies worldwide. With current therapeutic approaches the prognosis of gastric cancer is very poor, as gastric cancer accounts for the second most common cause of death in cancer related deaths. Gastric cancer like almost all other cancers has a molecular genetic basis which relies on disruption in normal cellular regulatory mechanisms regarding cell growth, apoptosis and cell division. Thus novel therapeutic approaches such as gene therapy promise to become the alternative choice of treatment in gastric cancer. In gene therapy, suicide genes, tumor suppressor genes and anti-angiogenesis genes among many others are introduced to cancer cells via vectors. Some of the vectors widely used in gene therapy are Adenoviral vectors. This review provides an update of the new developments in adenoviral cancer gene therapy including strategies for inducing apoptosis, inhibiting metastasis and targeting the cancer cells.

Expression of vascular endothelial growth factor (VEGF) and epidermal growth factor receptor (EGFR) is an independent prognostic indicator of worse outcome in gastric cancer patients

BACKGROUND

Unlike other human tumors, gastric cancer remains a great therapeutic challenge since no standardized postoperative treatment exists. Knowledge of molecular pathways determining the behavior of individual gastric tumors seems to be crucial for therapeutic decisions, and evaluation of vascular endothelial growth factor (VEGF) and epidermal growth factor receptor (EGFR) expression might be critical for prognosis, assessment, and identification of patients that could be treated with tailored therapies.

METHODS

VEGF and EGFR determination was performed in 88 gastric cancer samples as well as 25 normal gastric mucosa specimens from non-cancer patients using a commercially available immunohistochemistry kit. In all samples, the correlation of VEGF and EGFR expression was investigated with each other, and with other prognostic indicators in all samples, and, finally, with survival rates in 69 patients undergoing potentially curative surgery.

RESULTS

Forty-eight per cent (42 cases) of gastric cancers expressed VEGF, and 44% (39 cases) stained for EGFR. In curatively treated patients, VEGF and EGFR expression was demonstrated to correlate with worse survival in both univariate and multivariate analyses. Molecular profiling was shown to more accurately estimate the risk of cancer-related death than TNM stage, and, of most interest, to allow sorting out high-risk patients within the same stage.

CONCLUSIONS

These findings provide evidence that contemporary evaluation of VEGF and EGFR expression may be crucial to select gastric cancer patients with poor prognosis who may benefit of tailored treatments.

Effect of MDR1 C3435T polymorphism on cure rates of Helicobacter pylori infection by triple therapy with lansoprazole, amoxicillin and clarithromycin in relation to CYP 2C19 genotypes and 23S rRNA genotypes of H. pylori

BACKGROUND

Polymorphism in MDR1 is associated with variation in the plasma level of a proton pump inhibitor.

AIM

To investigate whether MDR1 polymorphism is associated with eradication rates of Helicobacter pylori by a triple therapy with lansoprazole, amoxicillin and clarithromycin in relation to CYP2C19 genotype status and bacterial susceptibility to clarithromycin.

METHODS

A total of 313 patients infected with H. pylori completed the treatment with lansoprazole 30 mg b.d., clarithromycin 200 mg b.d. and amoxicillin 750 mg b.d. for 1 week. MDR1 C3435T polymorphism and CYP2C19 genotypes of patients and sensitivity of H. pylori to clarithromycin were determined.

RESULTS

Logistic regression analysis revealed that the MDR1 polymorphism as well as CYP2C19 genotypes of patients and clarithromycin-resistance of H. pylori were significantly associated with successful eradication. Eradication rates for H. pylori were 82% (83/101: 95% CI = 73-89), 81% (112/139: CI = 73-87), and 67% (44/73: CI = 48-72) in patients with the MDR1 3435 C/C, C/T and T/T genotype, respectively (P = 0.001).

CONCLUSIONS

Polymorphism of MDR1 is one of the determinants of successful eradication of H. pylori by the triple therapy with lansoprazole, amoxicillin and clarithromycin, together with CYP2C19 genotype and bacterial susceptibility to clarithromycin.

Personalized medicine for eradication of Helicobacter pylori

Regimens for eradication of Helicobacter pylori consist of a proton-pump inhibitor (PPI) and one or two antimicrobial agents, such as amoxicillin, clarithromycin or metronidazole. As the pharmacokinetics and pharmacodynamics of PPIs are affected by polymorphism of CYP2C19, doses and dosing schemes of a PPI should be optimized based on genotype status of each patient in order to yield higher eradication rates. PPIs affect the pharmacokinetics of other substrates of CYP2C19, such as warfarin and diazepam. Acid inhibition induced by a PPI also affects the pharmacokinetics of some drugs, such as itraconazole. Clarithromycin, one of the most frequently used antimicrobial agents in eradication of H. pylori, inhibits activity of CYP3A4, meaning that the pharmacokinetics of substrates of CYP3A4 are affected by clarithromycin. Therefore, clinicians must pay attention to the other drugs dosed to each of their patients. Therefore, the eradication regimen for H. pylori infection should be designed with the CYP2C19 genotype status, bacterial susceptibility to antimicrobial agents, and other drugs being taken by each patient having been taken into consideration.