Clinical relevance of Helicobacter pylori virulence factors in Iranian patients with gastrointestinal diseases

GDF6 in gastric cancer upregulated by helicobacter pylori induces epithelial-mesenchymal translation via the TGF-β/SMAD3 signaling pathway

OBJECTIVE

To investigate the association between Helicobacter pylori infection and GDF6 expression in gastric cancer patients, and to determine its influence on prognosis and resistance to capecitabine.

METHODS

Tumor and adjacent non-tumor tissues were collected from 148 gastric cancer patients who underwent surgery in our department from October 2019 to June 2022. Of these patients, 78 tested positive for Helicobacter pylori and 70 tested negative. Hematoxylin-eosin (HE) and immunofluorescence staining were utilized to quantify GDF6 expression in cancerous and adjacent tissues. Patient prognosis was monitored via follow-up. Western blotting analyzed GDF6 expression in common gastric cancer cell lines. HGC27 cells exhibiting high GDF6 expression and BGC823 cells with low expression were used to create GDF6-silenced and overexpressed cell lines. The impact of GDF6 on the proliferation, migration, invasion, and cloning abilities of gastric cancer cells was evaluated using the CCK-8 assay, scratch test, Transwell assay, and plate colony formation assay. Fluorescent quantitative PCR and Western blotting assessed the effects of GDF6 levels on epithelial-mesenchymal transition (EMT) and tumor cell stemness.

RESULTS

GDF6 expression in gastric cancer tissues was significantly correlated with cancer grading and staging (P<0.05). Helicobacter pylori-positive tissues exhibited significantly higher GDF6 expression levels than negative samples (P<0.05). Kaplan-Meier survival analysis indicated that high GDF6 expression was associated with poor survival prognosis. Overexpressed GDF6 enhanced the proliferation, migration, and invasion abilities of gastric cancer cells, while silencing GDF6 yielded opposite results. Increased GDF6 expression upregulated TGF-β expression and the phosphorylation levels of SMAD3, leading to an elevation in mesenchymal cell markers N-cadherin, vimentin, and a reduction in epithelial cell markers cytokeratins, E-cadherin. Moreover, high GDF6 levels contributed to increased resistance to capecitabine and enhanced the expression of tumor stem cell markers Nanog, Sox-2, Oct-4, CD44, amplifying tumor cell stemness.

CONCLUSION

Helicobacter pylori infection is associated with increased GDF6 expression in gastric cancer tissue, correlating with poor survival prognosis. Elevated GDF6 expression promotes the proliferation, migration, and invasion abilities of gastric cancer cells, facilitates EMT via the TGF-β/SMAD3 pathway, and intensifies cell stemness and capecitabine resistance. Consequently, GDF6 presents itself as a potential new target for gastric cancer treatment.

DATA AVAILABILITY STATEMENT

The data that support the findings of this study are available from the corresponding author upon reasonable request.

Microparticles and nanoparticles-based approaches to improve oral treatment of Helicobacter pylori infection

Helicobacter pylori is a gram-negative, spiral-shaped, flagellated bacterium that colonizes the stomach of half the world's population. Helicobacter pylori infection causes pathologies of varying severity. Standard oral therapy fails in 15-20% since the barriers of the oral route decrease the bioavailability of antibiotics and the intrinsic factors of bacteria increase the rates of resistance. Nanoparticles and microparticles are promising strategies for drug delivery into the gastric mucosa and targeting H. pylori. The variety of building blocks creates systems with distinct colloidal, surface, and biological properties. These features improve drug-pathogen interactions, eliminate drug depletion and overuse, and enable the association of multiple actives combating H. pylori on several fronts. Nanoparticles and microparticles are successfully used to overcome the barriers of the oral route, physicochemical inconveniences, and lack of selectivity of current therapy. They have proven efficient in employing promising anti-H. pylori compounds whose limitation is oral route instability, such as some antibiotics and natural products. However, the current challenge is the applicability of these strategies in clinical practice. For this reason, strategies employing a rational design are necessary, including in the development of nano- and microsystems for the oral route.

Relationship between mucosal TNF-α expression and Th1, Th17, Th22 and Treg responses in Helicobacter pylori infection

Helicobacter pylori (H. pylori)-induced gastric inflammation in the gastric mucosa and significantly increases the risk of developing gastritis and peptic ulcer disease (PUD). The objective of this research is to determine the role of tumor necrosis factor-α (TNF-α) expression in the gastric mucosa of patients with H. pylori-associated gastritis and PUD compared to uninfected patients, and we determined the relation between TNF-α expression and Th1/Th17/Th22, and Treg cells. Fifty-five patients with H. pylori-associated gastritis, 47 patients with H. pylori-associated PUD, and 48 uninfected patients were in this research. Antrum biopsy was used to detect H. pylori, virulence factors and histopathological assessments. Expression of TNF-α in the infected group was significantly higher than the uninfected group. Also, cagA/oipA-positive infected patients induce significantly more TNF-α expression than do cagA/oipA-negative infected patients. Expression of TNF-α was significantly increased in the PUD group than the gastritis group. Notably, TNF-α expression had a significant positive correlation with the frequency of Th1/Th17/Th22 lymphocytes in the PUD group. These findings indicate the importance of increasing TNF-α with Th1, Th17, Th22 responses increase as an important risk factor for PUD in context of H. pylori infection.

Expression of TNF-α was significantly increased in the PUD group than the gastritis group.

Notably, TNF-α expression had a significant positive correlation with the frequency of Th1/Th17/Th22 lymphocytes in the PUD group.

These findings indicate the importance of increasing TNF-α with Th1, Th17, Th22 responses increase as an important risk factor for PUD in context of H. pylori infection.

The role of non-coding RNA in the diagnosis and treatment of Helicobacter pylori-related gastric cancer, with a focus on inflammation and immune response

Helicobacter pylori (H. pylori) is one of the globally recognized causative factors of gastric cancer (GC). Currently, no definite therapy and drugs for H. pylori-related GC have been widely acknowledged although H. pylori infection could be eradicated in early stage. Inflammation and immune response are spontaneous essential stages during H. pylori infection. H pylori may mediate immune escape by affecting inflammation and immune response, leading to gastric carcinogenesis. As an important component of transcriptome, non-coding RNAs (ncRNAs) have been proven to play crucial roles in the genesis and development of H. pylori-induced GC. This review briefly described the effects of ncRNAs on H. pylori-related GC from the perspective of inflammation and immune response, as well as their association with inflammatory reaction and immune microenvironment. We aim to explore the potential of ncRNAs as markers for the early diagnosis, prognosis, and treatment of H. pylori-related GC. The ncRNAs involved in H. pylori-related GC may all hold promise as novel therapeutic targets for immunotherapy.

Frequency of virulence-associated genotypes of Helicobacter pylori and their correlation with clinical outcome and histological parameters in infected patients

Helicobacter pylori (H. pylori) is a gram-negative which can cause several gastroduodenal diseases, including gastritis and peptic ulcer disease (PUD). H. pylori specific genotypes have been related to increased occurrence of gastritis and PUD. The aim of this study was to investigate the clinical relevance of the major virulence factors of H. pylori with clinical outcomes and histological parameters in Iranian patients. Totally, 200 subjects with PUD and gastritis disease who underwent gastroduodenal endoscopy were enrolled in this study. The presence of the cagA, vacA, oipA, babA2, and iceA genes in antral gastric biopsy specimens were determined by polymerase chain reaction (PCR) and the results were compared with clinical outcomes and histological parameters. The frequency of babA2 ⁺ , oipA ⁺ , vacA s1/m2, and vacA m2 genes was significantly higher in patients with peptic ulcer disease compared with patients with gastritis. In contrast, the frequency of vacA s1/m1 gene was significantly higher in gastritis subjects than PUD subjects. The high-density scores of H. pylori were strongly associated with iceA1 ^¯ , babA2 ⁺ , and oipA ⁺ genes. Additionally, the high polymorphonuclear cell infiltration and high mononuclear cell infiltration scores were strongly associated with the cagA ⁺ , iceA1 ^¯ , oipA ⁺ genes and cagA ⁺ , babA2 ⁺ , oipA ⁺ genes, respectively. Our study indicated that the vacA, babA2, and oipA virulence factors are related to a higher risk of PUD in subjects with H. pylori-infection. Infection with these strains was associated with a more severe gastropathy.

Increased Indoleamine 2, 3-Dioxygenase expression modulates Th1/Th17/Th22 and Treg pathway in humans with Helicobacter Pylori-Infected gastric mucosa

INTRODUCTION AND PURPOSE

Indoleamine 2, 3- dioxygenase (IDO) plays an importantrole in immunosuppressive pathway, as inhibits responsesof T cells and promotes immune tolerance. Host responsetoHelicobacter pylori (H. pylori) is involved in the infection persistenceand it is also associatedwith different clinical outcomes. The aim of this study was to investigate the role of IDO in H. pylori-infected patients with gastritis diseases and peptic ulcer diseases (PUD) through the assessment of the relationship among IDO protein expression and the numbers of T helper (Th)-1, Th17, Th22, and T regulator (Treg) cells.

MATERIALS AND METHODS

Antrum biopsy was obtained from H. pylori-negative patients (n = 48) and H. pylori-positive subjects (55 patients with gastritis and 47 patients with PUD), for performing H. pylori status and histopathological assessments. IDO protein expression was evaluated by Western blotting.

RESULTS

IDO protein expression was significantly higher in gastric biopsies from H. pylori-positive subjects compared to the H. pylori-negative subjects, and also in H. pylori-positive subjects with gastritis disease compared to H. pylori-positive subjects with PUD. Moreover, in H. pylori-positive subjects, a positive correlation was observed between IDO protein expression and the frequency of Treg cells. In addition, a negative correlation was observed between IDO protein expression and the number of Th1, Th17, and Th22.

CONCLUSION

Increased IDO protein expression is able to change the number of Th1, Th17, Th22, and Treg cells and these changes are possibly associated with an increase in the risk of PUD development in H. pylori-infected patients.

Molecular Mechanism of Helicobacter pylori-Induced Gastric Cancer

Introduction

Various types of cancers threaten human life. The role of bacteria in causing cancer is controversial, but it has been determined that the Helicobacter pylori infection is one of the identified risk factors for gastric cancer. Helicobacter pylori infection is highly prevalent, and about half of the world^,s population is infected with it.

Objective

The aim of this study was the role of Helicobacter pylori in the development of gastric cancer.

Method

We obtained information from previously published articles.

Results and Conclusion

The bacterium has various virulence factors, including cytotoxin- associated gene A, vacuolating cytotoxin A, and the different outer membrane proteins that cause cancer by different mechanisms. These virulence factors activate cell signaling pathways such as PI3-kinase/Akt, JAK/STAT and Ras, Raf, and ERK signaling that control cell proliferation. Uncontrolled proliferation can lead to cancer.

From genes polymorphisms to mucosal expression of cytokines: evaluating IL-23/IL-17 axis in adult patients with gastritis

Background and Objective

Chronic inflammation is the typical sign of gastritis that may shift into gastric cancer. IL-17A and IL-17F as a novel inflammatory cytokines subset of CD4+Th play the main role in inflammation. A key cytokine receptor in the inflammatory IL-17/IL-23 axis, the interleukin 23 receptor (IL23R), may be related to gastritis. We evaluated the correspondence between IL-17A G197A, IL-17F A7488G and IL23R+2199 A/C polymorphisms with TGF-β1, IL-6, IL-17, IL-21 and IL-23 mucosal mRNAs expression in uninfected H. Pylori (HP) chronic gastritis patients.

Materials and Methods

Total RNA and genomic DNA were separated from gastric biopsies of 44 patients with gastritis. Subsequently, mucosal mRNAs expression of TGF-β1, IL-6, IL-17, IL-21 and IL-23 were assessed by real-time PCR. To polymorphisms determination of IL-17A G197A, IL-17F A7488G and IL-23R +2199A/C the PCR-RFLP was used in gastric biopsies.

Results

Results point that IL-17A G197A, IL-17F A7488G and IL23R +2199A/C polymorphisms did not influence the mucosal expression of TGF-β1, IL-6, IL-17 and IL-21 (p> 0.05). In an opposite result, we don't find a correspondence between IL-17A G197A, IL-17F A7488G polymorphisms and mucosal expression of IL-23 (p> 0.05). In a contrary, we found a correlation between IL23R +2199A/C polymorphism and mucosal expression of IL-23 in patients with chronic gastritis (p< 0.05).

Conclusion

These findings propose that IL23R +2199A/C polymorphism may change the mucosal expression of IL-23 pattern in patients with gastritis disease in the absence of HP, but to support the conclusion, more research may be required.

Up-regulated CCL18, CCL28 and CXCL13 Expression is Associated with the Risk of Gastritis and Peptic Ulcer Disease in Helicobacter Pylori infection

BACKGROUND

Helicobacter pylori (H. pylori) infection causes inflammation and increases the risk of developing peptic ulcer disease (PUD); however, the exact molecular mechanisms of PUD development remain unclear. The aim of this study was to investigate the expression of CCL18, CCL28, and CXCL13 in H. pylori-positive subjects in comparison with H. pylori-negative subjects, and to determine its association with different clinical outcomes and virulence factors.

METHODS

In total, 55 H. pylori-positive subjects with gastritis, 47 H. pylori-positive subjects with PUD, and 48 H. pylori-negative subjects were enrolled in this study. CCL18, CCL28, and CXCL13 expression were determined using real time polymerase chain reaction (PCR). The virulence factors of H. pylori such as cytotoxin-associated gene A (cagA), outer inflammatory protein A (oipA), blood group antigen-binding adhesin (babA), and vacuolating cytotoxin A (VacA) genes were evaluated using PCR.

RESULTS

CCL18, CCL28, and CXCL13 expression in H. pylori-positive subjects were significantly higher than H. pylori-negative subjects. CCL18 and CXCL13 expression in H. pylori-positive subjects with oipA⁺ and babA2⁺were significantly higher than H. pylori-positive subjects with oipA¯ and babA2¯. CCL18 and CXCL13 expression were found to be significantly elevated in H. pylori-positive subjects with gastritis compared with H. pylori-positive subjects with PUD. CCL28 expression was significantly higher in H. pylori-positive subjects with PUD compared with H. pylori-positive subjects with gastritis.

CONCLUSIONS

The increased of CCL18 and CXCL13 may be involved in the pathogenesis of H. pylori-associated gastritis, while the increased of CCL28 may be involved in the pathogenesis of H. pylori-associated PUD.

Is there a relationship between Helicobacter pylori vacA i1 or i2 alleles and development into peptic ulcer and gastric cancer? A meta-analysis study on an Iranian population

Helicobacter pylori has several virulance factor i.e. VacA, CagA, BabA, SabA, AlpA, AlpB and etc. VacA has several polymorphic region in the nucleotide sequence such as s,m,i,d and, c. It has been suggested that each variation in these polymorphic region has been influenced the toxicity of VacA toxin. We performed a comprehensive meta-analysis to determine the main role of VacAi1/i2 in development into peptic ulcer and gastric cancer in an Iranian population.

Clarithromycin-Susceptible But Virulent Helicobacter pylori Strains Infecting Iranian Patients' Stomachs

Introduction

Helicobacter pylori was discovered first in the stomachs of patients with gastritis and ulcers by Marshall and Warren in 1982. This discovery majorly affected many research areas of gastroenterology. Since then, the main aim has been to eradicate this microaerophilic bacterium from the stomachs of infected subjects.

Methods

We studied symptomatic cases by endoscopic surgery and examined the prevalence of cagA-vacA genotypes among the H. pylori isolates. H. pylori isolated from antral biopsies of patients with gastritis and duodenal ulcer were subjected to antimicrobial susceptibility testing and PCR genotyping by using routine bacterial cultures. Clarithromycin-susceptibility profiling was done by the E-test. DNA was extracted using standard manufacturer protocols with minor modifications and cagA and vacA genotyping was done PCR.

Results

In our study, all strains identified as H. pylori in culture (61/81) were confirmed by PCR by amplifying a fragment of the glmM gene. Totally, 61 patients were confirmed to be positive for H. pylori and they were included in the genotyping and antibiotic-susceptibility testing. Thirteen H. pylori strains were determined to be resistant to clarithromycin.

Discussion

Current accumulating data indicate that both clarithromycin-resistant and susceptible isolates of H. pylori need to be screened and tracked in populations.

T-bet+ Cells Polarization in Patients Infected with Helicobacter pylori Increase the Risk of Peptic Ulcer Development

BACKGROUND

Peptic ulcer disease (PUD) is a common disease worldwide moreover known as stomach ulcer or peptic ulcer. Increased the number of T CD4⁺ helper cells in response to gastric infection by Helicobacter pylori (H. pylori) play an important role in the development of PUD. The aim of this study was to determine the frequency of T-bet⁺ cells in H. pylori-infection, its interaction with Th17/Treg cells and its association with the clinical consequences of the infection.

METHODS

A total of 63 patients with PUD, 89 patients with gastritis and 48 H. pylori-negative subjects were enrolled in this study. The number of T-bet⁺ cells were determined by immunohistochemistry.

RESULTS

The numbers of T-bet⁺ cells and INF-γ expression in infected patients were significantly higher than uninfected. Moreover, the number of T-bet⁺ cells and INF-γ expression in infected patients with PUD were significantly higher than infected patients with gastritis. Additionally, the number of T-bet⁺ cells and INF-γ expression were found to be inversely correlated with degree of H. pylori density and chronic inflammation score (CIS) in infected patients with gastritis disease, but this correlation was positive in the infected patients with PUD. The number of T-bet⁺ cells was found to be positively correlated with the number of Th17 cells and inversely correlated with the number of Treg cells in infected patients with gastritis and PUD.

CONCLUSION

Abnormal hyper-activation of T-bet⁺ cells during H. pylori-infection may lead to tissue damage caused by immunopathologic reactions.

HONEY-DERIVED LACTOBACILLUS RHAMNOSUS ALLEVIATES HELICOBACTER PYLORI-INDUCED GASTRO-INTESTINAL INFECTION AND GASTRIC INFLAMMATION IN C57BL/6 MICE: AN IMMUNO-HISTOLOGIC STUDY

BACKGROUND

Helicobacter pylori (H. pylori) has been introduced by since 1983 by Marshal and Warren to play the main role in the pathophysiology of gastritis and gastric ulcers. Almost half of the world population1 is infected by H. pylori. Current therapeutic regimen against H. pylori includes the use of a proton pump inhibitor plus two or more antibiotics. However, the efficacy of this regimen is decreasing mainly due to antibiotic resistance and side effects of medications. This fact has resulted in public interest in other therapeutic options and the role of probiotics merits special attention in this regard.

OBJECTIVE

This study aims to evaluate the efficacy of honey-derived Lactobacillus rhamnosus on H. pylori-induced gastric inflammation and gastro-intestinal infection in C57BL/6 Mice.

METHODS

The 24 C57BL/6 Mice were randomly divided into three groups of eight mice each. All the mice were fed with 1cc suspension containing 5*1010 CFU/ mL of ATCC43504 strains of H. pylori for 3 consecutive days, twice daily via polyethylene gavage tubes. At the end of 4th week, infection with H. pylori was confirmed with stool Ag (ELISA) and following sacrifice of one mouse from each group, histopathologic study confirmed gastritis. The groups were subjected to different therapies as stated, 1: without Bismuth (Bi), Omeprazole (Om) and L. rhamnosus prescription, 2: Bi, Om and Clarithromycin (Cl) and 3: Bi, Om plus 1cc of suspension of 109 CFU/mL of L. rhamnosus. After 2 weeks, the stool was analyzed for Ag and the mice were sacrificed for evaluation of histopathologic changes.

RESULTS

Treatment with L. rhamnosus group provided Zero titer of stool Ag and was associated with improved gastric inflammation in all subjects, similar to the clarithromycin group.

CONCLUSION

Honey-derived L. rhamnosus probiotics provides similar results as clarithromycin in terms of improvement of H. pylori infection and gastritis in C57BL/6 Mice model, without its cons of antibiotic resistance.

Genotyping and antibiotic resistance properties of Helicobacter pylori strains isolated from human and animal gastric biopsies

Purpose

The present study was done to assess the prevalence rate, antibiotic resistance pattern and genotyping status of the Helicobacter pylori strains isolated from human and animal gastric biopsy samples.

Patients and methods

A total of 1,150 gastric biopsy samples were randomly collected from humans (children and adults) and animals (cows, sheep and goats). All samples were subjected to culture, urease test and histopathologic examination. H. pylori isolates were also confirmed using the 16S rRNA gene PCR-amplification. Antibiotic resistance pattern was assessed by the disk diffusion method. Distribution of different genotypes was studied by PCR.

Results

The prevalence of H. pylori in gastric biopsy samples which were studied using urease test, culture and histological examination were 57.04%, 55.40% and 60.80%, respectively. Samples that were collected from adult humans (78%) and sheep (70%) had the highest prevalence of H. pylori strains, while those of goats (0.6%) and cows (4%) had the lowest. Findings of the culture method were confirmed using PCR-based amplification of 16S rRNA. Distribution of H. pylori among the gastric ulcers, duodenal ulcers, chronic gastritis gastric cancer and chronic cancer samples were 10.40%, 15.70%, 96.50%, 0.60% and 3.14%, respectively. H. pylori strains harbored the highest prevalence of resistance against ampicillin (74.4%), clarithromycin (63.4%), trimethoprim (61.5%) and metronidazole (61.5%). The most commonly detected genotypes among the H. pylori strains isolated from different types of biopsy samples were cagA (84.79%), vacA m2 (55.95%), vacA s1a (49.84%), cagE (48.58%), iceA1 (47.02%) and iceA2 (47.02%).

Conclusion

High prevalence of antibiotic resistance and virulent genotypes indicates an important public health issue. Similarities in antibiotic resistance and genotyping pattern of H. pylori strains isolated from humans and animals may show their similar routes of infection.

The role of T helper 1-cell response in Helicobacter pylori-infection

Helicobacter pylori (H. pylori) is a human pathogen affecting over 50% of the world population. This pathogen is usually associated with chronic inflammation of the gastric mucosa that can lead to peptic ulcer disease (PUD) and gastric cancer (GC), especially in susceptible individuals. These outcomes have been attributed to the interaction of several factors, including host genetic susceptibility, local innate and adaptive immune responses, virulence factors of H. pylori, and environmental factors. T helper (Th) cell subsets and their signature cytokines especially IFN-γ, contribute to anti-bacterial response, but at the mean time sustaining chronic inflammatory responses in the site of infection. It has been acknowledged that H. pylori-infection results in a Th1-dominant response and that inflammation of the gastric mucosa depends mainly on Th1 cell responses. But, the mechanism of the role of Th1 cell responses in H. pylori-infection has not yet been clearly explained. In this review, we will focus on the role of Th1 involved in H. pylori-infection, its interaction with Th17/Treg cells and its association with the clinical consequences of the infection.

New insights of Helicobacter pylori host-pathogen interactions: The triangle of virulence factors, epigenetic modifications and non-coding RNAs

Helicobacter pylori (H. pylori) is a model organism for understanding host-pathogen interactions and infection-mediated carcinogenesis. Gastric cancer and H. pylori colonization indicates the strong correlation. The progression and exacerbation of H. pylori infection are influenced by some factors of pathogen and host. Several virulence factors involved in the proper adherence and attenuation of immune defense to contribute the risk of emerging gastric cancer, therefore analysis of them is very important. H. pylori also modulates inflammatory and autophagy process to intensify its pathogenicity. From the host regard, different genetic factors particularly affect the development of gastric cancer. Indeed, epigenetic modifications, MicroRNA and long non-coding RNA received more attention. Generally, various factors related to pathogen and host that modulate gastric cancer development in response to H. pylori need more attention due to develop an efficacious therapeutic intervention. Therefore, this paper will present a brief overview of host-pathogen interaction especially emphases on bacterial virulence factors, interruption of host cellular signaling, the role of epigenetic modifications and non-coding RNAs.

Up-regulated Th17 cell function is associated with increased peptic ulcer disease in Helicobacter pylori-infection

BACKGROUND

During Helicobacter pylori (H. pylori) infection CD4⁺ T cells in the gastric lamina propria are hyporesponsive and polarized by Th1/Th17 cell responses controlled by Treg cells. The objective of this study was to determine the number of Th17 cells in gastric mucosa of patients with gastritis and peptic ulcer and determined the relationship between main virulence factor of H. pylori and Th17 cells.

METHODS AND MATERIALS

A total of 89 H. pylori-infected gastritis patients, 63 H. pylori-infected peptic ulcer patients and 48 H. pylori-negative non-ulcer dysplasia patients were enrolled in this study. The number of Th17 was determined by immunohistochemistry. IL-8 and IL-17A expressions were determined by real-time polymerase chain reaction (qPCR). Also, the grade of chronic and active inflammation was investigated for involvement according to the density of neutrophils and mononuclear in gastric mucosal crypts, from one to all crypts.

RESULTS

The number of Th17 cells and the expression of IL-8 and IL-17A in infected patients were significantly higher than uninfected subjects. The number of Th17 cells and the expression of IL-8 and IL-17A in infected patients with peptic ulcer were significantly higher than patients with gastritis. Additionally, the numbers of Th17 cells as well as the expression of IL-8 and IL-17A were positively correlated with the degree of H. pylori density in infected patients with peptic ulcer, while this correlation was negative in infected patients with gastritis. The numbers of Th17 cells as well as the expression of IL-8 and IL-17A were positively correlated with the degree of chronic inflammation.

CONCLUSION

The predominant Th17 cell responses may play a role in the pathogenesis of peptic ulcers disease in infected patients.

Influence of Helicobacter pylori virulence factors CagA and VacA on pathogenesis of gastrointestinal disorders

Helicobacter Pylori (H. pylori) is a gram-negative bacteria infecting numerous people all over the world. It has been established that H. pylori play an important role in pathogenesis of gastritis, peptic ulcer and gastric cancer. Pathogenic features of this bacterium are mainly attributes to the existence of pathogenic islands (PAI) genes. The most known genes in these islands are cytotoxin-associated gene A (CagA) and vacuolating cytotoxin gene (VacA). Most studies demonstrated various frequency of CagA and VacA in patient with peptic ulcer or gastritis in different countries. This variation in CagA and VacA frequency may be due to the capability of this bacterium to be genetically versatile and can alter the expression of these genes with geographic diversity. Although H. pylori infection is not usually associated with any clinical symptoms, but sometimes leads to inflammation in gastrointestinal system and resulted in peptic ulcer and gastric cancer. In this regard, this review will illustrate the importance of Helicobacter pylori in pathogenesis of gastrointestinal disorders with focusing on CagA and VacA virulence factors.

cag Pathogenicity island-dependent upregulation of matrix metalloproteinase-7 in infected patients with Helicobacter pylori

Helicobacter pylori (H. pylori) infection has been involved in the pathogenesis of most important gastroduodenal diseases. Matrix metalloproteinases (MMPs) are a large family of zincendopeptidases which play important roles in degradation of extracellular matrix (ECM) and various inflammatory diseases. Therefore, we examined MMP-7 mRNA levels in the gastric mucosa of patients with H. pylori infection and evaluated the effects of virulence factors, such as vacA (vacuolating cytotoxin A) and cagA (cytotoxin-associated gene), in H. pylori-infected patients upon the MMP-7 mRNA mucosal levels. We also determined the correlation between mucosal MMP-7 mRNA levels and the types of disease. Total RNA was extracted from gastric biopsies of 50 H. pylori-infected patients and 50 uninfected individuals. Mucosal MMP-7 mRNA expression level in H. pylori-infected and non-infected gastric biopsies was determined by real-time polymerase chain reaction (PCR). The presences of cagA and vacA virulence factors was evaluated using PCR. MMP-7 expression was significantly higher in biopsies of patients infected with H .pylori compared to uninfected individuals. In addition, mucosal MMP-7 mRNA expression in H. pylori-infected patients significantly associated with the cagA status and the types of disease. Our results suggest that MMP-7 might be involved in the pathogenesis of H. pylori. Peptic ulcer was associated with cag pathogenicity island-dependent MMP-7 upregulation.

Downregulated regulatory T cell function is associated with increased peptic ulcer in Helicobacter pylori-infection

BACKGROUND

Helicobacter pylori (H. pylori) chronically colonizes gastric/duodenal mucosa and induces gastroduodenal disease such as gastritis and peptic ulcer and induces vigorous innate and specific immune responses; however, the infection is not removed, a state of chronic active gastritis persists for life if untreated. The objective of this study was to determine the number of regulatory T cells (Tregs) in gastric mucosa of patients with gastritis and peptic ulcer and determined the relationship between main virulence factor of H. pylori and Tregs.

METHODS AND MATERIALS

A total of 89 patients with gastritis, 63 patients with peptic ulcer and 40 healthy, H. pylori-negative subjects were enrolled in this study. Expression of CD4 and Foxp3 was determined by immunohistochemistry. Antrum biopsy was obtained for detection of H. pylori, bacterial virulence factors and histopathological assessments. TGF-β1, IL-10 and FOXP3 expressions were determined by real-time polymerase chain reaction (qPCR).

RESULTS

The numbers of CD4⁺ and Foxp3⁺ T cells as well as the expression of IL-10, TGF-β1, FOXP3, INF-γ and IL-17A in infected patients were significantly higher than the ones in uninfected patients. Also, the number of CD4⁺ T cells was independent on the vacuolating cytotoxin A (vacA) and outer inflammatory protein A (oipA), but it was positively correlated with cytotoxin-associated gene A (cagA). Instead, the number of Foxp3⁺ T cells was dependent on the vacA and oipA, but it was independent on cagA. The number of Foxp3⁺ T cells and the expression of IL-10, TGF-β1 and FOXP3 in infected patients with gastritis were significantly higher than the ones in infected patients with peptic ulcer. Moreover, the number of CD4⁺ T cells and the expression of IL-17A and INF-γ was the lowest in the gastritis patients, however, increased progressively in the peptic ulcer patients. Additionally, the numbers of CD4⁺ and Foxp3⁺ T cells as well as the expression of IL-10, TGF-β1, FOXP3 and INF-γ were positively correlated with the degree of H. pylori density and chronic inflammation.

CONCLUSION

Tregs are positively associated with vacA alleles and oipA status of H. pylori and histological grade but negatively associated with peptic ulcer disease.

Relationship between histopathological status of the Helicobacter pylori infected patients and proteases of H. pylori in isolates carrying diverse virulence genotypes

Helicobacter pylori is the main cause of several gastroduodenal diseases in Humans. Among various virulence factors of H. pylori, proteases may also be involved in its pathogenicity. In this study, relationship between proteolytic activity of H. pylori strains and histopathological changes of the stomach was investigated in the patients infected with strains carrying diverse virulence factors. H. pylori strains were isolated from the biopsies of 116 patients who referred to hospital for their gastroduodenal disorders, in Tehran, Iran. Biopsies were sent to microbiology and pathology laboratories for further analysis. All the suspected grown colonies were characterized by both biochemical tests and polymerase chain reaction (PCR). Presence of seven protease genes, htrA, clpP, hp0169, hp1012, hp0382, hp1350 and hp1435, and distinct allelic variants of H. pylori virulence factors, cagA, vacA, iceA, babA2 and sabA, were analyzed in each strain. Protease activity of the strains was assessed using spectrophotometric assay. Furthermore, association between diversity in protease genes and virulence genes, protease activity, as well as pathological changes was estimated statistically. Proteases genes, htrA, clpP, hp0169, hp1012, hp0382, hp1350, hp1435, were detected among 100%, 100%, 98%, 98%, 98%, 98%, and 8% of fifty H. pylori strains isolated from the patients, respectively. Status of cagA, vacA s1, vacA s2, vacA m1, vacA m2, iceA1, iceA2, babA2 and sabA genes in isolates were 64%, 68%, 30%, 26%, 74%, 48%, 52%, 100%, and 96%, respectively. Predominant (84%) combined status for protease genes was: htrA/clpP/hp0169/hp1012/hp0382/hP1350/hp1435, while the prevalent combined status (16%) for virulence genes was: cagA+/vacA s1m2/iceA1⁺/sabA⁺/babA2⁺. Although most of the strains (91.4%) presented moderate protease activity in vitro, lowest activity was measured in strains isolated from the patients with chronic gastritis (4.25%). Present study provide the new data on diversity of protease genes in H. pylori, as well as the proteolytic activity of these genes in H. pylori strains from the sick patients. Presence of significant association between lower protease activity of the strains and mildness of the pathological changes propose involvement of these proteases in the pathogenesis of H. pylori in vivo.