Natural history of gastric mucosal cytokine expression in Helicobacter pylori gastritis in Mongolian gerbils

A Bifidobacterium animalis subsp. lactis strain that can suppress Helicobacter pylori: isolation, in vitro and in vivo validation

The administration of probiotics is an effective approach for treatment of Helicobacter pylori, which is associated with human gastrointestinal diseases and cancers. To explore more effective probiotics for H. pylori infection elimination, bacteria from infant feces were screened in this study. We successfully isolated the Bifidobacterium animalis subsp. lactis strains and evaluated its efficacy to inhibit H. pylori growth in vitro and in vivo. The results showed that a B. animalis strain (named BB18) sustained a high survival rate after incubation in gastric juice. The rapid urease test suggested that B. animalis BB18 reduced pathogen loads in H. pylori-infected Mongolian gerbils. Alleviation of H. pylori infection-induced gastric mucosa damage and decreased levels inflammatory cytokines were observed after the B. animalis BB18 administration. These findings demonstrated that B. animalis BB18 can inhibit H. pylori infection both in vitro and in vivo, suggesting its potential application for the prevention and eradication therapy of H. pylori infection.

Low-grade intestinal metaplasia in Indonesia: Insights into the expression of proinflammatory cytokines during Helicobacter pylori infection and unique East-Asian CagA characteristics

Helicobacter pylori infection is a major cause of intestinal metaplasia. In this study, we aimed to understand the reason underlying the low grade and incidence of intestinal metaplasia in Indonesia, based on the expression of genes encoding proinflammatory cytokines in gastric biopsy specimens. The possible reasons for the lesser virulence of the East-Asian-type CagA in Indonesia than that of the Western-type CagA, which is not common in other countries, were also investigated. The mRNA expression of cytokines was evaluated using real-time PCR. CagA characteristics were analyzed using in silico analysis. The expression of cytokines was typically not robust, among H. pylori-infected subjects in Indonesia, despite them predominantly demonstrating the East-Asian-type CagA. This might partially be explained by the characteristics of the East-Asian-type CagA in Indonesia, which showed a higher instability index and required higher energy to interact with proteins related to the cytokine induction pathway compared with the other types (p < 0.001 and p < 0.05, respectively). Taken together, besides the low prevalence of H. pylori, the low inflammatory response of the host and low CagA virulence, even among populations with high infection rates, may play an essential role in the low grade and low incidence of intestinal metaplasia in Indonesia. We believe that these findings would be relevant for better understanding of intestinal metaplasia, which is closely associated with the development of gastric cancer.

Long-term improvement in constipation-related symptoms after Helicobacter pylori eradication therapy

BACKGROUND

Helicobacter pylori eradication therapy effectively improves the abnormal bowel habits and abdominal symptoms of patients for a few months post-treatment (PT). However, it is unclear whether the improvement in abnormal bowel habits and symptoms continues long term. Here, we investigated the association of successful H. pylori eradication therapy with improvements in abdominal symptoms in the short- and long-term PT.

MATERIALS AND METHODS

We evaluated the severity of constipation-related abdominal symptoms in 287 H. pylori-positive patients who underwent eradication therapy at pre-treatment and 2 and 12 months PT using two measures: the Gastrointestinal Symptom Rating Scale (GSRS) and the Izumo scale.

RESULTS

In patients with constipation at pre-treatment, constipation-related symptom scores in the GSRS improved significantly from 7.91 ± 3.15 at pre-treatment to 6.07 ± 2.75 at 2 months PT (p < 0.01) and 6.85 ± 3.46 at 12 months PT (p = 0.04). Patients with improved symptom scores at 2 months PT also experienced an improvement at 12 months PT. In contrast, patients who did not experience an improvement in constipation-related symptoms at 2 months PT likewise did not experience an improvement at 12 months PT.

CONCLUSIONS

Patients who experience an improvement at 2 months PT with H. pylori eradication therapy continue to experience improved symptoms in the long term. Therefore, H. pylori -positive patients with abnormal bowel habits should be recommended eradication therapy to prevent gastric cancer development and to alleviate abnormal bowel habits and abdominal symptoms.

T Cell Cytokines Impact Epithelial Cell Responses during Helicobacter pylori Infection

The goal of this Brief Review is to highlight literature that demonstrates how cytokines made by T lymphocytes impact the gastric epithelium, especially during Helicobacter pylori infection. These cytokines effect many of the diverse functions of the epithelium and the epithelium's interactions with H. pylori The focal point of this Brief Review will be on how T cell cytokines impact antimicrobial function and barrier function and how T cell cytokines influence the development and progression of cancer. Furthermore, the modulation of epithelial-derived chemokines by H. pylori infection will be discussed.

Effect of Brugia pahangi co-infection with Plasmodium berghei ANKA in gerbils (Meriones unguiculatus)

Malaria and lymphatic filariasis (LF) are two leading and common mosquito-borne parasitic diseases worldwide. These two diseases are co-endemic in many tropical and sub-tropical regions and are known to share vectors. The interactions between malaria and filarial parasites are poorly understood. Thus, this study aimed at establishing the interactions that occur between Brugia pahangi and Plasmodium berghei ANKA (PbA) co-infection in gerbils. Briefly, the gerbils were matched according to age, sex, and weight and grouped into filarial-only infection, PbA-only infection, co-infection, and control group. The parasitemia, survival and clinical assessment of the gerbils were monitored for a period of 30 days post Plasmodium infection. The immune responses of gerbils to both mono and co-infection were monitored. Findings show that co-infected gerbils have higher survival rate than PbA-infected gerbils. Food and water consumption were significantly reduced in both PbA-infected and co-infected gerbils, although loss of body weight, hypothermia, and anemia were less severe in co-infected gerbils. Plasmodium-infected gerbils also suffered hypoglycemia, which was not observed in co-infected gerbils. Furthermore, gerbil cytokine responses to co-infection were significantly higher than PbA-only-infected gerbils, which is being suggested as a factor for their increased longevity. Co-infected gerbils had significantly elicited interleukin-4, interferon-gamma, and tumor necrotic factor at early stage of infection than PbA-infected gerbils. Findings from this study suggest that B. pahangi infection protect against severe anemia and hypoglycemia, which are manifestations of PbA infection.

IL-10 Plays a Pivotal Role in Tamoxifen-Induced Spasmolytic Polypeptide-Expressing Metaplasia in Gastric Mucosa

Background/Aims

Gastric cancer evolves in the pathologic mucosal milieu, and its development is characterized by both the loss of acid-secreting parietal cells and mucosal cell metaplasia, called spasmolytic polypeptide-expressing metaplasia (SPEM). Cytokines, such as interleukin (IL)-10, IL-1β, and IL-6, play a key role in gastric carcinogenesis. However, changes in the cytokine profile of SPEM have not been evaluated.

Methods

To induce SPEM in mouse stomachs, C57BL/6 mice were intraperitoneally injected with tamoxifen and sacrificed at 3, 10, and 21 days after treatment. RNA-sequencing (RNA-seq) and a multiplex bead array were used to measure cytokines in the stomachs of tamoxifen-treated/control mice.

Results

The administration of tamoxifen led to the rapid development and histological normalization of SPEM 3 and 10 days after administration, respectively. RNA-seq revealed that the expression of IL-10 was decreased 3 days after tamoxifen administration. The multiplex assay identified a significant decline in IL-10 levels 3 days after tamoxifen treatment (58.38±34.44 pg/mL vs 94.09±4.98 pg/mL, p=0.031), which normalized at 10 and 21 days after tamoxifen treatment. Immunofluorescence staining confirmed that IL-10 expression was markedly decreased at the time of SPEM development and subsequently returned to normal, accompanied by a reversal in histologic changes.

Conclusions

IL-10 may play a pivotal role in the tamoxifen-induced acute development of gastric SPEM.

Cytokines, Antibodies, and Histopathological Profiles during Giardia Infection and Variant-Specific Surface Protein-Based Vaccination

Giardiasis is one of the most common human intestinal diseases worldwide. Several experimental animal models have been used to evaluate Giardia infections, with gerbils (Meriones unguiculatus) being the most valuable model due to their high susceptibility to Giardia infection, abundant shedding of cysts, and pathophysiological alterations and signs of disease similar to those observed in humans. Here, we report cytokine and antibody profiles both during the course of Giardia infection in gerbils and after immunization with a novel oral vaccine comprising a mixture of purified variant-specific surface proteins (VSPs). Transcript levels of representative cytokines of different immune profiles as well as macro- and microtissue alterations were assessed in Peyer's patches, mesenteric lymph nodes, and spleens. During infection, cytokine responses showed a biphasic profile: an early induction of Th1 (gamma interferon [IFN-γ], interleukin-1β [IL-1β], IL-6, and tumor necrosis factor [TNF]), Th17 (IL-17), and Th2 (IL-4) cytokines, together with intestinal alterations typical of inflammation, followed by a shift toward a predominant Th2 (IL-5) response, likely associated with a counterregulatory mechanism. Conversely, immunization with an oral vaccine comprising the entire repertoire of VSPs specifically showed high levels of IL-17, IL-6, IL-4, and IL-5, without obvious signs of inflammation. Both immunized and infected animals developed local (intestinal secretory IgA [S-IgA]) and systemic (serum IgG) humoral immune responses against VSPs; however, only infected animals showed evident signs of giardiasis. This is the first comprehensive report of cytokine expression and anti-Giardia antibody production during infection and VSP vaccination in gerbils, a reliable model of the human disease.

Native and bone marrow-derived cell mosaicism in gastric carcinoma in H. pylori-infected p27-deficient mice

Objective

Chronic Helicobacter pylori (H. pylori) infection promotes non-cardia gastric cancer. Some mouse models suggest that bone marrow derived cells (BMDC) contribute to Helicobacter-associated gastric carcinogenesis. We determined whether this increased susceptibility to Helicobacter-induced gastric carcinogenesis of p27-deficient mice is dependent upon their p27-null BMDC or their p27-null gastric epithelial cells.

Design

Female mice (recipients) were irradiated and transplanted with BMDC from male donors. Wild type (WT) mice in group 1 (control) received BMDC from male GFP-transgenic mice. Female WT and p27 KO mice were engrafted with male p27KO mice BMDC (Group 2) or GFP-transgenic WT BMDC (Group 3). Recipients were infected with H. pylori SS1 for one year.

Results

Mice lacking p27 in either the BM pool or gastric epithelium developed significantly more advanced gastric pathology, including high-grade dysplasia. Co-staining of donor BMDC in dysplastic gastric glands was confirmed by immunofluorescence. Gastric expression of IL-1 beta protein was reduced in groups 2 and 3 (p < 0.05 vs control) whereas expression of IFN-γ and chemokines MIP-1 beta, MIG, IP-10 and RANTES in group 2 were significantly higher than group 3.

Conclusions

Both bone marrow-derived and gastric epithelial cells contribute to the increased gastric cancer susceptibility of p27-deficient H. pylori-infected mice.

The Mongolian Gerbil: A Robust Model of Helicobacter pylori-Induced Gastric Inflammation and Cancer

The Mongolian gerbil is an efficient, robust, and cost-effective rodent model that recapitulates many features of H. pylori-induced gastric inflammation and carcinogenesis in humans, allowing for targeted investigation of the bacterial determinants and environmental factors and, to a lesser degree, host constituents that govern H. pylori-mediated disease. This chapter discusses means through which the Mongolian gerbil model has been used to define mechanisms of H. pylori-inflammation and cancer as well as the current materials and methods for utilizing this model of microbially induced disease.

Pathogenesis of Plasmodium berghei ANKA infection in the gerbil (Meriones unguiculatus) as an experimental model for severe malaria

Background: As the quest to eradicate malaria continues, there remains a need to gain further understanding of the disease, particularly with regard to pathogenesis. This is facilitated, apart from in vitro and clinical studies, mainly via in vivo mouse model studies. However, there are few studies that have used gerbils (Meriones unguiculatus) as animal models. Thus, this study is aimed at characterizing the effects of Plasmodium berghei ANKA (PbA) infection in gerbils, as well as the underlying pathogenesis. Methods: Gerbils, 5-7 weeks old were infected by PbA via intraperitoneal injection of 1 × 10⁶ (0.2 mL) infected red blood cells. Parasitemia, weight gain/loss, hemoglobin concentration, red blood cell count and body temperature changes in both control and infected groups were monitored over a duration of 13 days. RNA was extracted from the brain, spleen and whole blood to assess the immune response to PbA infection. Organs including the brain, spleen, heart, liver, kidneys and lungs were removed aseptically for histopathology. Results: Gerbils were susceptible to PbA infection, showing significant decreases in the hemoglobin concentration, RBC counts, body weights and body temperature, over the course of the infection. There were no neurological signs observed. Both pro-inflammatory (IFNγ and TNF) and anti-inflammatory (IL-10) cytokines were significantly elevated. Splenomegaly and hepatomegaly were also observed. PbA parasitized RBCs were observed in the organs, using routine light microscopy and in situ hybridization. Conclusion: Gerbils may serve as a good model for severe malaria to further understand its pathogenesis.

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.

Supplementation with Angelica keiskei inhibits expression of inflammatory mediators in the gastric mucosa of Helicobacter pylori-infected mice

Oxidative stress is involved in the pathogenesis of Helicobacter pylori-associated gastric ulceration and carcinogenesis. The oxidant-sensitive transcription factor, nuclear factor κ-light-chain-enhancer of activated B cells (NF-κB), regulates expression of inflammatory mediators such as interferon γ (IFN-γ), cyclooxygenase 2 (COX-2), and inducible nitric oxide synthase (iNOS). These inflammatory mediators increased in gastric mucosal tissues from patients infected with H pylori. Angelica keiskei (AK), a green leafy vegetable, is rich in carotenoids and flavonoids and shows antioxidant and anti-inflammatory activities. Therefore, we hypothesized that AK may protect the gastric mucosa of H pylori-infected mice against inflammation. We determined lipid peroxide abundance, myeloperoxidase activity, expression levels of inflammatory mediators (IFN-γ, COX-2, and iNOS), NF-κB-DNA binding activity, and histologic changes in gastric mucosal tissues. The antioxidant N-acetylcysteine served as the positive control treatment. Supplementation with AK suppressed increases in lipid peroxide abundance, myeloperoxidase activity, induction of inflammatory mediators (IFN-γ, COX-2, and iNOS), activation of NF-κB, and degradation of nuclear factor of κ light polypeptide gene enhancer in B-cells inhibitor α in gastric mucosal tissue from H pylori-infected mice. Inhibition of H pylori-induced alterations by AK was similar to that by N-acetylcysteine. Taken together, these results suggest that supplementation with AK may prevent H pylori-induced gastric inflammation by inhibiting NF-κB-mediated induction of inflammatory mediators in the gastric mucosa of patients infected with H pylori.

Association Between IL-17, IL-8 and IL-18 Expression in Peripheral Blood and Helicobacter Pylori Infection in Mongolian Gerbils

Background:

Persistent Helicobacter pylori infection confers an increased risk for serious illnesses such as peptic ulcers and gastric cancer. Various cytokines are involved in the regulation of inflammatory immune response in H. pylori-infected gastric mucosa.

Objectives:

The current study aimed to obtain evidence regarding the association between IL-17, IL-8 and IL-18 expression in peripheral blood and H. pylori infection in Mongolian gerbils.

Materials and Methods:

Mongolian gerbils were inoculated with H. pylori by a metal stomach catheter. After sacrifice, their gastric mucosae were examined in macroscopic, histological and electron microscopy levels. In addition, enzyme linked immunosorbent assay (ELISA) assay was performed on the IL-17, IL-8 and IL-18 cytokines in the blood samples.

Results:

Serum levels of IL-17, IL-8 and IL-18 were remarkably up-regulated compared to those of the control group. There was an obvious correlation between the increase of IL-17 and the serious extent of gastritis in the current study. However, the serum levels of IL-8 and IL-18 without getting increasingly more for repetitive intragastric administration. There were plenty of neutrophils infiltrating in the infected group mucosal. Intestinal metaplasia and gastric ulcers were also founded in H. pylori infected animals after enhanced inoculation. The edema, degeneration and necrosis changes could be found in organelles by transmission electron microscopy. More serious pathological changes were detected in the enhanced inoculation groups compared to the cycle group.

Conclusions:

The serum levels of IL-17, but not IL-8 and IL-18 may serve as a potential biomarker for diagnosis and predicting the prognosis of gastritis caused by H. pylori.

Toll-like Receptor 10 in Helicobacter pylori Infection

Innate immunity plays important roles in the primary defense against pathogens, and epidemiological studies have suggested a role for Toll-like receptor 1 (TLR1) in Helicobacter pylori susceptibility. Microarray analysis of gastric biopsy specimens from H. pylori-positive and uninfected subjects showed that TLR10 messenger RNA (mRNA) levels were upregulated approximately 15-fold in infected subjects; these findings were confirmed by real-time quantitative polymerase chain reaction analysis. Immunohistochemical investigation showed increased TLR10 expression in the gastric epithelial cells of infected individuals. When H. pylori was cocultured with NCI-N87 gastric cells, both TLR10 and TLR2 mRNA levels were upregulated. We compared the ability of TLR combinations to mediate nuclear factor-κB (NF-κB) activation. Compared with other TLR2 subfamily heterodimers, the TLR2/TLR10 heterodimer mediated the greatest NF-κB activation following exposure to heat-killed H. pylori or H. pylori lipopolysaccharide. We conclude that TLR10 is a functional receptor involved in the innate immune response to H. pylori infection and that the TLR2/TLR10 heterodimer functions in H. pylori lipopolysaccharide recognition.

Early or late antibiotic intervention prevents Helicobacter pylori-induced gastric cancer in a mouse model

H. pylori infection causes gastritis, peptic ulcers and gastric cancer. Eradicating H. pylori prevents ulcers, but to what extent this prevents cancer remains unknown, especially if given after intestinal metaplasia has developed. H. pylori infected wild-type (WT) mice do not develop cancer, but mice lacking the tumor suppressor p27 do so, thus providing an experimental model of H. pylori-induced cancer. We infected p27-deficient mice with H. pylori strain SS1 at 6-8 weeks of age. Persistently H. pylori-infected WT C57BL/6 mice served as controls. Mice in the eradication arms received antimicrobial therapy (omeprazole, metronidazole and clarithromycin) either "early" (at 15 weeks post infection, WPI) or "late" at 45 WPI. At 70 WPI, mice were euthanized for H. pylori determination, histopathology and cytokine/chemokine expression. Persistently infected mice developed premalignant lesions including high-grade dysplasia, whereas those given antibiotics did not. Histologic activity scores in the eradication groups were similar to each other, and were significantly decreased compared with controls for inflammation, epithelial defects, hyperplasia, metaplasia, atrophy and dysplasia. IP-10 and MIG levels in groups that received antibiotics were significantly lower than controls. There were no significant differences in expression of IFN-γ, TNF-α, IL-1β, RANTES, MCP-1, MIP-1α or MIP-1β among the three groups. Thus, H. pylori eradication given either early or late after infection significantly attenuated gastric inflammation, gastric atrophy, hyperplasia, and dysplasia in the p27-deficient mice model of H. pylori-induced gastric cancer, irrespective of the timing of antibiotic administration. This was associated with reduced expression of IP-10 and MIG.

Early or late antibiotic intervention prevents Helicobacter pylori-induced gastric cancer in a mouse model

H. pylori infection causes gastritis, peptic ulcers and gastric cancer. Eradicating H. pylori prevents ulcers, but to what extent this prevents cancer remains unknown, especially if given after intestinal metaplasia has developed. H. pylori infected wild-type (WT) mice do not develop cancer, but mice lacking the tumor suppressor p27 do so, thus providing an experimental model of H. pylori-induced cancer. We infected p27-deficient mice with H. pylori strain SS1 at 6-8 weeks of age. Persistently H. pylori-infected WT C57BL/6 mice served as controls. Mice in the eradication arms received antimicrobial therapy (omeprazole, metronidazole and clarithromycin) either "early" (at 15 weeks post infection, WPI) or "late" at 45 WPI. At 70 WPI, mice were euthanized for H. pylori determination, histopathology and cytokine/chemokine expression. Persistently infected mice developed premalignant lesions including high-grade dysplasia, whereas those given antibiotics did not. Histologic activity scores in the eradication groups were similar to each other, and were significantly decreased compared with controls for inflammation, epithelial defects, hyperplasia, metaplasia, atrophy and dysplasia. IP-10 and MIG levels in groups that received antibiotics were significantly lower than controls. There were no significant differences in expression of IFN-γ, TNF-α, IL-1β, RANTES, MCP-1, MIP-1α or MIP-1β among the three groups. Thus, H. pylori eradication given either early or late after infection significantly attenuated gastric inflammation, gastric atrophy, hyperplasia, and dysplasia in the p27-deficient mice model of H. pylori-induced gastric cancer, irrespective of the timing of antibiotic administration. This was associated with reduced expression of IP-10 and MIG.

Associations of a TLR4 single-nucleotide polymorphism with H. pylori associated gastric diseases in Iranian patients

OBJECTIVE

Helicobacter pylori (H. pylori) is associated with gastric ulcer and gastric adenocarcinoma. Polymorphisms in the host genes coding for toll-like receptors (TLRs) may influence the innate and adaptive immune response to the infection, affecting the susceptibility to H. pylori or the disease outcomes. But the details and association to different polymorphisms and different clinical expressions in patients infected with H. pylori (different clinical expression of H. pylori infection) remain unclear.

METHODS

A case-control study consisting of 195 patients with H. pylori infection and 241 H. pylori uninfection was conducted. Genomic DNA was extracted and genotypes of TLR4Asp299Gly polymorphism were assessed through polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). Presence of cagA was evaluated using PCR.

RESULTS

TLR4 (Asp299Gly) G and DG alleles frequency in H. pylori infected population was significantly higher in the chronic gastritis group than in the chronic active gastritis group (P=0.021; OR, 2.409; 95% CI, 1.124-5.162). Grade mononuclear (MN) infiltration in H. pylori infected patients with DG genotype of TLR-4 Asp299Gly increased significantly. CagA positivity was more frequently associated with chronic active gastritis (P=0.017, OR=2.26, 95% CI=1.144-4.462) and grade polymorphonucler (PMN) infiltration.

CONCLUSION

TLR-4 Asp299Gly G allele substitution may be modified pattern of immune response in the gastric mucosa of H. pylori infected patients and may be H. pylori infected patients with gastritis have increased risk for the development of chronic gastritis. CagA positivity may be a risk factor for development of gastritis.

Inhibitory effect of Raphanobrassica on Helicobacter pylori-induced gastritis in Mongolian gerbils

Helicobacter pylori (H. pylori) infection is well known to be associated with chronic gastritis and also development of gastric cancer. Raphanobrassica (RB) is an intergeneric hybrid of the genera Raphanus (radish) and Brassica (cabbages) containing appreciable amounts of glucoraphanin (GR) and glucoraphenin (GRe), which are actively hydrolyzed by the enzyme myrosinase to sulforaphane and sulforaphene, respectively. Both of these metabolites exert antimicrobial and anti-inflammatory activity. The purpose of the present study was to investigate the effect of two freeze-dried products of RB (RB1 and RB2) on H. pylori-induced gastritis in Mongolian gerbils. Six-week-old male Mongolian gerbils were inoculated orally with H. pylori (ATCC 43504), and 2weeks later were fed diets containing no additives or diets supplemented with 2% RB1 (containing both GR and GRe) or 2% RB2 (containing GR only) for 10weeks. In the RB1, but not the RB2 group, mononuclear cell infiltration, mRNA expression of IL-6, and cell proliferation in the gastric mucosa were significantly suppressed. These results indicate that RB1 containing both GR and GRe exerted significant inhibitory effects on H. pylori-induced gastritis in Mongolian gerbils apparently mediated via suppression of IL-6 expression and chronic inflammation.

Virulence factors of Helicobacter pylori vacA increase markedly gastric mucosal TGF-β1 mRNA expression in gastritis patients

OBJECTIVE

Helicobacter pylori (H. pylori) infection is the main cause of gastric inflammation. Regulatory T cells (Treg cells) suppress the activation and proliferation of antigen-specific T cells and mediate immunologic tolerance. TGF-β1 was shown to be secreted in a subset of Treg cells known as 'Th3 cells'. These cells have not been sufficiently studied in context to H. pylori-induced inflammation in human gastric mucosa. In this study we therefore, aimed to investigate the expression of TGF-β1 in the context of H. pylori colonization in chronic gastritis, to examine the relationship between it and histopathologic findings and to compare it with virulence factors.

PATIENTS AND METHODS

Total RNA was extracted from gastric biopsies of 48 H. pylori-infected patients and 38 H. pylori-negative patients with gastritis. Mucosal TGF-β1 mRNA expression in H. pylori-infected and uninfected gastric biopsies was determined by real-time PCR. Presence of vacA, cagA, iceA, babA2 and oipA virulence factors was evaluated using PCR.

RESULTS

TGF-β1 mRNA expression was significantly increased in biopsies of H. pylori-infected patients compared to H. pylori-uninfected patients. There was association between virulence factors and TGF-β1 mRNA expression. TGF-β1 mRNA expression in mucosa was significantly higher in patients with vacA s1 and s1m1.

CONCLUSIONS

TGF-β1 may play an important role in the inflammatory response and promote the chronic and persistent inflammatory changes in the gastric. This may ultimately influence the outcome of H. pylori-associated diseases that arise within the context of gastritis and vacA may suffice to induce expression of TGF-β1 mRNA.

Diversity in bacterium-host interactions within the species Helicobacter heilmannii sensu stricto

Helicobacter (H.) heilmannii sensu stricto (s.s.) is a zoonotic bacterium that naturally colonizes the stomach of dogs and cats. In humans, this microorganism has been associated with gastritis, peptic ulcer disease and mucosa associated lymphoid tissue (MALT) lymphoma. Little information is available about the pathogenesis of H. heilmannii s.s. infections in humans and it is unknown whether differences in virulence exist within this species. Therefore, a Mongolian gerbil model was used to study bacterium-host interactions of 9 H. heilmannii s.s. strains. The colonization ability of the strains, the intensity of gastritis and gene expression of various inflammatory cytokines in the stomach were determined at 9 weeks after experimental infection. The induction of an antrum-dominant chronic active gastritis with formation of lymphocytic aggregates was shown for 7 strains. High-level antral colonization was seen for 4 strains, while colonization of 4 other strains was more restricted and one strain was not detected in the stomach at 9 weeks post infection. All strains inducing a chronic active gastritis caused an up-regulation of the pro-inflammatory cytokine IL-1β in the antrum. A reduced antral expression of H⁺/K⁺ ATPase was seen in the stomach after infection with 3 highly colonizing strains and 2 highly colonizing strains caused an increased gastrin expression in the fundus. In none of the H. heilmannii s.s.-infected groups, IFN-γ expression was up-regulated. This study demonstrates diversity in bacterium-host interactions within the species H. heilmannii s.s. and that the pathogenesis of gastric infections with this microorganism is not identical to that of an H. pylori infection.

Transgenic expression of interferon-γ in mouse stomach leads to inflammation, metaplasia, and dysplasia

Gastric adenocarcinoma is one of the leading causes of cancer mortality worldwide. It arises through a stepwise process that includes prominent inflammation with expression of interferon-γ (IFN-γ) and multiple other pro-inflammatory cytokines. We engineered mice expressing IFN-γ under the control of the stomach-specific H(+)/K(+) ATPase β promoter to test the potential role of this cytokine in gastric tumorigenesis. Stomachs of H/K-IFN-γ transgenic mice exhibited inflammation, expansion of myofibroblasts, loss of parietal and chief cells, spasmolytic polypeptide expressing metaplasia, and dysplasia. Proliferation was elevated in undifferentiated and metaplastic epithelial cells in H/K-IFN-γ transgenic mice, and there was increased apoptosis. H/K-IFN-γ mice had elevated levels of mRNA for IFN-γ target genes and the pro-inflammatory cytokines IL-6, IL-1β, and tumor necrosis factor-α. Intracellular mediators of IFN-γ and IL-6 signaling, pSTAT1 and pSTAT3, respectively, were detected in multiple cell types within stomach. H/K-IFN-γ mice developed dysplasia as early as 3 months of age, and 4 of 39 mice over 1 year of age developed antral polyps or tumors, including one adenoma and one adenocarcinoma, which expressed high levels of nuclear β-catenin. Our data identified IFN-γ as a pivotal secreted factor that orchestrates complex changes in inflammatory, epithelial, and mesenchymal cell populations to drive pre-neoplastic progression in stomach; however, additional alterations appear to be required for malignant conversion.

Sequence determination of the heavy-chain constant region in four immunoglobulin classes of Mongolian gerbils (Meriones unguiculatus)

We determined partial cDNA sequences of four immunoglobulin (Ig) classes-IgM, IgG1, IgE, and IgA-of Mongolian gerbil (Meriones unguiculatus). Each deduced Ig heavy-chain constant (IGHC) region-Cµ, Cγ1, Cε, and Cα-is structurally similar to its counterparts in the mouse and rat, and phylogenetic analysis suggests that the gerbil Igs are evolutionarily close to their counterparts. In spite of the high sequence homology to the other rodent Cγ sequences, the gerbil Cγ1 sequence differs from our previously reported Cγ2. This result indicates that the gerbil has at least two IgG subclasses. These four gerbil IGHC cDNA sequences will be useful for determining gerbil Ig isotypes and examining the expression of gerbil Ig mRNAs in response to parasitic and bacterial infections.

Helicobacter pylori outer membrane proteins on gastric mucosal interleukin 6 and 11 expression in Mongolian gerbils

BACKGROUND AND AIM

The levels of interleukin (IL)-6 and IL-11 in the gastric mucosa are related to mucosal inflammation; however, the chronological changes in cytokine expression during different phases of Helicobacter pylori infection and the effects of H. pylori virulence factors, particularly those of outer membrane proteins, remain obscure. The aim of this study was to clarify the chronological changes in cytokine levels in relation to several H. pylori outer membrane proteins.

METHODS

We studied Mongolian gerbils inoculated with wild-type H. pylori 7.13 for up to 48 weeks and then examined animals infected with oipA, babA, or alpAB isogenic mutants for 12 weeks. Mucosal IL-6 and IL-11 mRNA levels were measured using real-time reverse transcription-polymerase chain reactions.

RESULTS

High levels of gastric mucosal IL-6 and IL-11 mRNA in gerbils infected with wild-type H. pylori were observed during the chronic phase of infection, reaching maximums at 12 and 6 months, respectively. Infection with oipA and babA mutants resulted in significantly reduced cytokine levels and inflammatory cell infiltrations compared to gerbils infected with wild-type strains, and this persisted throughout the observation period. The alpAB mutants did not infect gerbils. Mucosal IL-6 and IL-11 levels were significantly associated with the grade of inflammatory cell infiltration.

CONCLUSIONS

OipA and BabA result in more severe H. pylori infection and increased IL-6 and IL-11 levels, which in turn may increase the risk of developing H. pylori-induced gastrointestinal diseases.

Expression of angiotensin II type 1 and type 2 receptor mRNAs in the gastric mucosa of Helicobacter pylori-infected Mongolian gerbils

BACKGROUND

The renin-angiotensin system (RAS) plays an important role in normal homeostasis, carcinogenesis-related angiogenesis, and cell proliferation. Helicobacter pylori infection causes infiltration of inflammatory cells into the gastric mucosa and is considered the major cause of gastric cancer. Whether RAS plays a role in H. pylori infection-related gastric diseases remains unclear. We investigated the changes in gastric mucosal angiotensin II type 1 receptor (AT1R) and type 2 receptor (AT2R) mRNA levels throughout the time course of H. pylori infection in Mongolian gerbils.

METHODS

Mongolian gerbils were infected with wild-type H. pylori (for 12 months) or with its isogenic oipA mutant (for 3 months). Gastric mucosal AT1R and AT2R mRNA levels were assessed using real-time reverse transcription-polymerase chain reaction.

RESULTS

The gastric mucosal AT1R mRNA level was significantly associated with the severity of inflammatory cell infiltration into the gastric mucosa that reached maximal levels at 12 months after infection in both the antrum and body. Inflammatory cell infiltration scores and AT1R and AT2R mRNA levels were significantly lower in oipA mutant than wild-type infections. Mucosal AT1R and AT2R mRNA expressions in wild-type H. pylori-infected gerbils with gastric ulcers were significantly higher than in those without ulcers (P < 0.01).

CONCLUSIONS

Gastric mucosal ATR expression gradually increases during the course of H. pylori infection. Up-regulation of the RAS in association with progressive gastric inflammation suggests a potential role of the RAS in gastric carcinogenesis. OipA appears to play a role in AT1R and AT2R expression and the resulting inflammation.

Gastric diseases in Mongolian gerbils infected with different strains of Helicobacter pylori

Helicobacter pylori (H.pylori) is a bacterium responsible for one of the most widespread infections found in humans. It colonizes the gastric mucosa and can result in chronic gastritis and gastric cancer. The incidence of spontaneous gastric gastritis is low in Mongolian gerbils, and spontaneous H.pylori infection can not be detected in this animal. Since H.pylori-related gastric diseases in Mongolian gerbils are very similar to those in humans, they have been considered as ideal animals to establish H.pylori infection models. However, different strains of H.pylori may induce different types of pathologic changes in Mongolian gerbils. Clarification of the pathogenic mechanisms of different strains of H.pylori may provide a theoretical basis for screening appropriate H.pylori strains and directing individualized treatment in patients with H.pylori-related gastric diseases. In this paper, we review the recent progress in research of gastric diseases in Mongolian gerbils infected with different strains of H.pylori.

Insufficient role of cell proliferation in aberrant DNA methylation induction and involvement of specific types of inflammation

Chronic inflammation is deeply involved in induction of aberrant DNA methylation, but it is unclear whether any type of persistent inflammation can induce methylation and how induction of cell proliferation is involved. In this study, Mongolian gerbils were treated with five kinds of inflammation inducers [Helicobacter pylori with cytotoxin-associated gene A (CagA), H.pylori without CagA, Helicobacter felis, 50% ethanol (EtOH) and saturated sodium chloride (NaCl) solution]. Two control groups were treated with a mutagenic carcinogen that induces little inflammation (20 p.p.m. of N-methyl-N-nitrosourea) and without any treatment. After 20 weeks, chronic inflammation with lymphocyte and macrophage infiltration was prominent in the three Helicobacter groups, whereas neutrophil infiltration was mainly observed in the EtOH and NaCl groups. Methylation levels of eight CpG islands significantly increased only in the three Helicobacter groups. By Ki-67 staining, cell proliferation was most strongly induced in the NaCl group, demonstrating that induction of cell proliferation is not sufficient for methylation induction. Among the inflammation-related genes, Il1b, Nos2 and Tnf showed increased expression specifically in the three Helicobacter groups. In human gastric mucosae infected by H.pylori, NOS2 and TNF were also increased. These data showed that inflammation due to infection of the three Helicobacter strains has a strong potential to induce methylation, regardless of their CagA statuses, and increased cell proliferation was not sufficient for methylation induction. It was suggested that specific types of inflammation characterized by expression of specific inflammation-related genes, along with increased cell proliferation, are necessary for methylation induction.

Brugia filariasis differentially modulates persistent Helicobacter pylori gastritis in the gerbil model

In select Helicobacter pylori-infected populations with low gastric cancer, nematode coinfections are common and both helicobacter gastritis and filariasis are modeled in gerbils. We evaluated gastritis, worm counts, tissue cytokine gene expression levels and Th1/Th2-associated antibody responses in H. pylori and Brugia pahangi mono- and coinfected gerbils. H. pylori-associated gastritis indices were significantly lower 21 weeks post-infection in coinfected gerbils (p < or = 0.05) and were inversely proportional to worm counts (r(2) = -0.62, p < 0.003). Additionally, IFN-gamma, IL-1 beta, CXCL1, IL-4 and IL-10 mRNA levels in the gastric antrum reflected a significant host response to gastric H. pylori and as well as systemic filariasis (p < or = 0.05). Despite increasing worm burden (p < 0.05), gastritis progressed in coinfected gerbils (p < 0.03) becoming equivalent to H. pylori-infected gerbils at 42 weeks (p = 0.7). Pro- and anti-inflammatory mediator mRNA levels were notably downregulated in B. pahangi infected gerbils below uninfected control values, suggesting hyporesponsiveness to B. pahangi. Consistent with an increasing Th1 response to H. pylori, IgG2a (p < 0.01), IL-1 beta (p = 0.04) and CXCL1 (p = 0.006) responses significantly increased and IL-4 (p = 0.05) and IL-10 (p = 0.04) were decreased in coinfected gerbils at 42 weeks. Initial systemic responses to B. pahangi resulted in attenuated gastritis in coinfected gerbils, but subsequent filarid-associated hyporesponsiveness appears to have promoted H. pylori gastritis.

Anti-inflammatory effects of caffeic acid phenethyl ester (CAPE), a nuclear factor-kappaB inhibitor, on Helicobacter pylori-induced gastritis in Mongolian gerbils

Nuclear factor-kappaB (NF-kappaB) plays a major role in host inflammatory responses and carcinogenesis and as such is an important drug target for adjuvant therapy. In this study, we examined the effect of caffeic acid phenethyl ester (CAPE), an NF-kappaB inhibitor, on Helicobacter pylori (H. pylori)-induced NF-kappaB activation in cell culture and chronic gastritis in Mongolian gerbils. In AGS gastric cancer cells, CAPE significantly inhibited H. pylori-stimulated NF-kappaB activation and mRNA expression of several inflammatory factors in a dose-dependent manner, and prevented degradation of IkappaB-alpha and phosphorylation of p65 subunit. To evaluate the effects of CAPE on H. pylori-induced gastritis, specific pathogen-free male, 6-week-old Mongolian gerbils were intragastrically inoculated with H. pylori, fed diets containing CAPE (0-0.1%) and sacrificed after 12 weeks. Infiltration of neutrophils and mononuclear cells and expression of NF-kappaB p50 subunit and phospho-IkappaB-alpha were significantly suppressed by 0.1% CAPE treatment in the antrum of H. pylori-infected gerbils. Labeling indices for 5'-bromo-2'-deoxyuridine both in the antrum and corpus and lengths of isolated pyloric glands were also markedly reduced at the highest dose, suggesting a preventive effect of CAPE on epithelial proliferation. Furthermore, in the pyloric mucosa, mRNA expression of inflammatory mediators including tumor necrosis factor-alpha, interferon-gamma, interleukin (IL)-2, IL-6, KC (IL-8 homologue), and inducible nitric oxide synthase was significantly reduced. These results suggest that CAPE has inhibitory effects on H. pylori-induced gastritis in Mongolian gerbils through the suppression of NF-kappaB activation, and may thus have potential for prevention and therapy of H. pylori-associated gastric disorders.

Gastric mucosal interleukin-17 and -18 mRNA expression in Helicobacter pylori-induced Mongolian gerbils

Helicobacter pylori infection causes characteristic mucosal infiltration of inflammatory cells, resulting in the development of peptic ulcers and gastric cancer in approximately 10% of cases. Different clinical expressions of the infection may reflect different patterns of cytokine expression. Interleukin (IL)-1ss, tumor necrosis factor (TNF)-alpha, IL-17, and IL-18 have been reported to be involved in H. pylori-induced gastric mucosal inflammation, but the details and relation to different patterns of inflammation remain unclear. Moreover, the proinflammatory virulence factor outer inflammatory protein (OipA) was reported to be associated with gastric mucosal inflammatory cytokine levels. To clarify these findings, Mongolian gerbils were infected for up to 12 months with wild-type H. pylori 7.13 or with isogenic oipA mutants for 3 months, and mucosal cytokines (IL-1ss, IL-17, IL-18, and TNF-alpha) mRNA levels were then assessed using real-time RT-PCR. Antral mucosal IL-1beta and IL-18 mRNA levels peaked 1 month after infection, whereas the peak of TNF-alpha mRNA was at 6-12 months; IL-17 levels peaked at 12 months. The inflammatory cell infiltration and mRNA levels of all cytokines studied were significantly lower in oipA mutants than in wild-type-infected gerbils. Mucosal IL-1ss, IL-17, and TNF-alpha expression, but not that of IL-18, were significantly associated with the grade of inflammatory cell infiltration. The pattern of increased inflammatory cytokines differed relative to the phase of the infection and pattern of inflammation. OipA appears to play a role in IL-1ss, IL-17, and TNF-alpha expression and the resulting inflammation.

Concurrent Helicobacter bilis infection in C57BL/6 mice attenuates proinflammatory H. pylori-induced gastric pathology

Because coinfections can alter helicobacter gastritis, we investigated whether enterohepatic Helicobacter bilis modulates Helicobacter pylori gastritis in C57BL/6 mice. Thirty mice per group were sham dosed, H. bilis or H. pylori infected, or H. bilis infected followed in 2 weeks by H. pylori and then evaluated at 6 and 11 months postinfection (mpi) for gastritis and premalignant lesions. Compared to H. pylori-infected mice, H. bilis/H. pylori-infected mice at 6 and 11 mpi had less severe gastritis, atrophy, mucous metaplasia and hyperplasia (P < 0.01) and, additionally, at 11 mpi, less severe intestinal metaplasia and dysplasia (P < 0.05). H. bilis/H. pylori-infected mice at 11 mpi exhibited less Ki67 labeling of proliferating epithelial cells, reduced numbers of FoxP3(+) T-regulatory (T(REG)) cells, and lower FoxP3(+) mRNA levels than did H. pylori-infected mice (P < 0.05). Proinflammatory interleukin-1beta (IL-1beta), gamma interferon, and tumor necrosis factor alpha mRNA levels were attenuated in H. bilis/H. pylori-infected mice at 6 and 11 mpi (P < 0.01), although anti-inflammatory IL-10, IL-13, and transforming growth factor beta1 mRNA levels were not consistently impacted by H. bilis coinfection. Decreased pathology in H. bilis/H. pylori-infected mice correlated with higher gastric H. pylori colonization at 6 mpi (P < 0.001) and lower Th1-associated immunoglobulin G2c responses to H. pylori at 6 and 10 mpi (P < 0.05). We hypothesized that reduced pathology in H. bilis/H. pylori-infected mice was due to H. bilis-primed T(REG) cells in the lower bowel that migrated to the gastric compartment and inhibited Th1 responses to subsequent H. pylori infection. Thus, H. pylori-induced gastric lesions may vary in mouse models of unknown enteric helicobacter infection status and, importantly, variable sequelae to human H. pylori infection, particularly in developing countries, may occur where coinfection with lower bowel helicobacters and H. pylori may be common.

Persistent H. pylori colonization in early acquisition age of mice related with higher gastric sialylated Lewis x, IL-10, but lower interferon-γ expressions

Background

H. pylori infection is less prevalent in childhood. This study validated whether the rates of H. pylori colonization depend on different acquisition ages, and correlate with the different gastric Lewis antigens or cytokine expressions after H. pylori acquisition.

Methods

We applied a young (7-day-old) C57BL/6 mice group (n = 50) and adult (6-week-old) C57BL/6 mice group (n = 50). In each group, 30 mice were challenged with H. pylori and 20 mice served as naïve control. The success of H. pylori colonization was assessed on the 2^nd week and the 8^th week, respectively. The intensity of the Lewis x, sialylated Lewis x(sialyl-Le^x), and cytokine expressions, including TNF-α, IFN-γ, IL-6, IL-10, and IL-1β, were immunochemically stained and graded.

Results

On the 2^nd week after H. pylori challenge, the colonization rates of H. pylori were similar between the young mice group and the adult mice group (89% vs. 100%, P > 0.05). However, on the 8^th week, the H. pylori colonization rate was significantly lower in the young mice group than in the adult mice group (53% vs. 95%, P = 0.003). On the 8^th week, the young mice with a persistence of H. pylori colonization had higher sialyl-Le^x, higher IL-10, and lower IFN-γ than those of the mice that lost colonization during the 2^nd to the 8^th week (P < 0.05).

Conclusion

The persistence of H. pylori colonization could be an acquisition-age determinant process. After H. pylori exposure at an early acquisition age, the host response with a higher sialyl-Le^x and IL-10, but a lower IFN-γ correlates to the consequent persistence of H. pylori colonization.

4-Vinyl-2,6-dimethoxyphenol (canolol) suppresses oxidative stress and gastric carcinogenesis in Helicobacter pylori-infected carcinogen-treated Mongolian gerbils

Oxidative stress is linked to gastric carcinogenesis because of its ability to damage DNA. Here we examined antioxidative and anti-inflammatory effects of 4-vinyl-2,6-dimethoxyphenol (canolol), a recently identified potent antioxidative compound obtained from crude canola oil, on Helicobacter (H.) pylori-induced gastritis and gastric carcinogenesis using a Mongolian gerbil model. The animals were allocated to H. pylori-infection alone (12 weeks) or H.pylori + N-methyl-N-nitrosourea (MNU) administration (52 weeks). After oral inoculation of H. pylori, they were fed for 10 and 44 weeks with or without 0.1% canolol. H. pylori-induced gastritis, 5'-bromo-2'-deoxyuridine (BrdU) labeling and scores for cyclooxygenase-2 (COX-2) and inducible nitric oxide synthase (iNOS) immunohistochemistry were attenuated in the canolol-treated groups. Expression of interleukin-1 beta (IL-1 beta), tumor necrosis factor-alpha (TNF-alpha), COX-2 and iNOS mRNA in the gastric mucosa, and serum 8-hydroxy-2'-deoxyguanosine (8-OHdG), anti-H. pylori IgG and gastrin levels were also significantly lower in canolol-treated groups. Furthermore, the incidence of gastric adenocarcinomas was markedly reduced in the H. pylori + MNU + canolol-treated group [15.0% (6/40)] compared to the control group [39.4% (13/33)] (p < 0.05). These data indicate canolol to be effective for suppressing inflammation, gastric epithelial cell proliferation and gastric carcinogenesis in H. pylori-infected Mongolian gerbils. Interestingly, the viable H. pylori count was not changed by the canolol containing diet. Thus, the data point to the level of inflammation because of H. pylori rather than the existence of the bacteria as the determining factor. Importantly, canolol appears to suppress induction of mRNAs for inflammatory cytokines.

Emergence of spasmolytic polypeptide-expressing metaplasia in Mongolian gerbils infected with Helicobacter pylori

Spasmolytic polypeptide (TFF2)-expressing metaplasia (SPEM) is observed in mucosa adjacent to human gastric cancer and in fundic glands showing oxyntic atrophy in Helicobacter felis-infected mice. Mongolian gerbils infected with Helicobacter pylori (Hp) develop goblet cell intestinal metaplasia and adenocarcinoma, but the presence of SPEM has not been studied in gerbils. We therefore have sought to examine the development of metaplastic mucosal changes in Hp-infected Mongolian gerbils. Mongolian gerbils were assigned to either uninfected controls or infected with Hp at 17 weeks of age. The animals were killed at 17, 20, 26, 31, 41 and 56 weeks of age. Stomach sections were stained using antibodies for TFF2, intrinsic factor, H/K-ATPase, BrdU and MUC2. Dual immunofluorescence staining for TFF2 with intrinsic factor and for TFF2 with MUC2 was performed. In uninfected animals, no SPEM or intestinal metaplasia was observed. Infected gerbils developed SPEM initially in the intermediate zone along the lesser curvature and subsequently spread out towards the greater curvature. In the earlier stages of infection, SPEM glands demonstrated TFF2 and intrinsic factor double staining cells. However, after 35 weeks of infection, the number of double staining SPEM cells decreased. While early in infection SPEM organized in straight glands, in the later stages of infections, SPEM glands became distorted or dilated along with the development of gastritis cystica profunda that was TFF2 positive. Goblet cell intestinal metaplasia developed only late in the infection. Dual staining for TFF2 and MUC2 showed glands containing both SPEM- and MUC2-positive goblet cell intestinal metaplasia. SPEM develops early in Hp infection in Mongolian gerbils, and alterations in gland morphology arise from SPEM glands during the course of gastric infection with goblet cell intestinal metaplasia developing subsequent to SPEM.

Severity of gastritis determines glandular stomach carcinogenesis in Helicobacter pylori-infected Mongolian gerbils

Helicobacter pylori (H. pylori) infection causes chronic gastritis and is also related to gastric carcinoma. The present study focused on severity of H. pylori-induced gastritis as a determinant of carcinogenesis. Seven-week-old male Mongolian gerbils were inoculated with H. pylori at experimental weeks 0, 12, or 18, then given N-methyl-N-nitorosourea (MNU) from weeks 20-40. At week 70, stomachs were then excised for histological examination 70, 58, or 52 weeks after H. pylori inoculation, respectively (Groups A, B, and C for long-, middle-, and short-term). The respective incidences of glandular stomach adenocarcinomas were 65.0% (13/20), 20.0% (2/10), and 23.0% (3/13) (P<0.05). Higher scores of infiltration of inflammatory cells, hyperplasia, intestinal metaplasia and mucosal bromodeoxyuridine (BrdU) labeling index in antrum and corpus mucosa, were seen in group A than B or C (P<0.05) and serum anti-H. pylori IgG titer and gastrin levels were also significantly higher, along with mRNA levels for mucosal interleukin-1beta (IL-1beta), tumor necrosis factor-alpha (TNF-alpha), cyclooxygenase-2 (COX-2), and inducible nitric oxide synthase (iNOS). The results demonstrated the term and severity of H. pylori infection to play important roles in gastric carcinogenesis, with essential involvement of chronic inflammation, especially increased rates of cell proliferation, in H. pylori-associated carcinogenesis.

Pattern of transcription factor activation in Helicobacter pylori-infected Mongolian gerbils

BACKGROUND AND AIMS

Helicobacter pylori interact with epithelial cells resulting in activation of cellular signaling pathways leading to an inflammatory response. The pattern and timing of transcription factor activation in H pylori-infected gastric mucosa remain unclear. We investigated the roles of transcription factors in the gastric mucosa of H pylori-infected gerbils over the course of the infection.

METHODS

Six-week-old male Mongolian gerbils were inoculated orally with H pylori TN2GF4 or isogenic cagE mutants and examined at 1, 3, 9, and 18 months. We examined the expression of 54 transcription factors using DNA/protein arrays and electrophoretic mobility shift assays. Phosphorylation status of mitogen-activated protein kinases and IkappaB were evaluated by immunoblot and immunohistochemistry.

RESULTS

Ten transcription factors were up-regulated by H pylori infection. Six of these factors, including activator protein-1 (AP-1) and cAMP responsive element binding protein (CREB), reached maximal levels at 3 months and were strongly correlated with cellular inflammation and ulceration. Phosphorylation of extracellular signal-regulated kinase correlated with activation of AP-1 and CREB. Levels of nuclear factor-kappaB and interferon-stimulated responsive element (ISRE) peaked at 18 months and correlated with the presence of severe atrophy and with phosphorylation of Jun-N-terminal kinase (JNK), p38, and IkappaB.

CONCLUSIONS

The gastric mucosal transcription factors induced by H pylori infection differed according to the phase and outcome of infection; AP-1 and CREB levels were early responders related to inflammation and ulceration, whereas NF-kappaB and ISRE were late responders related to atrophy.

Helicobacter pylori and gastric cancer

PURPOSE OF REVIEW

Although chronic Helicobacter pylori infection is the strongest known risk factor for development of gastric adenocarcinoma, only a small proportion of infected individuals will ever develop tumours. This article discusses various bacterial, host and environmental factors which may influence an individual's susceptibility.

RECENT FINDINGS

Recent research on bacterial virulence factors has focussed upon the cag pathogenicity island, particularly its roles in regulating epithelial growth and adhesion. Studies of host genetic factors have included several analyses of polymorphisms in inflammatory cytokines in human cohorts. Animal studies have recently clarified the roles of dysregulated epithelial apoptosis, proliferation and differentiation pathways during gastric carcinogenesis, and novel experiments involving H. felis infection of bone marrow transplanted irradiated mice have suggested that gastric cancer may originate from bone marrow-derived stem cells. Important roles for signalling between epithelial and mesenchymal cells, particularly myofibroblasts, are also emerging. Recent research on the importance of environmental factors has demonstrated how helminth coinfection may protect against atrophic gastritis and T helper type 1 responses.

SUMMARY

Complex interactions between several bacterial, host genetic and environmental factors determine whether H. pylori infected individuals develop gastric carcinoma. The importance of bone marrow stem cell engraftment during human gastric neoplasia is an area requiring urgent investigation.

A potential role of interferon-gamma in the pathogenesis of venous leg ulcers

Venous leg ulcer is the most severe expression of chronic venous insufficiency. Venous ulcerations are always associated with venous ambulatory hypertension, but the exact mechanism leading from pathological hemodynamics in venous circulation to the necrotic lesions in the skin still remains undiscovered. It has been shown that tissue injury in venous ulcer patients was induced by leukocytes. However, though infiltrating leukocytes have at their disposal a powerfully cytotoxic arsenal, it has not been discovered which molecular mechanisms may contribute to the skin damage. The search for this hypothetical factor responsible for the development of ulceration should be focused on mechanisms leading to apoptosis of keratinocytes, on pathogenesis of related dermatological pathologies, on other pathologies associated with epithelial lesions, and on mechanisms responsible for the expression of adhesion molecules. A thorough review of the literature, with special regard to cytokines, has revealed that proinflammatory cytokine--interferon-gamma (INFgamma)--could be a pivotal cytokine in the pathogenesis of venous ulceration. This cytokine, however, has not been investigated in venous leg ulcer patients before. INFgamma is a glycoprotein with numerous immunological and antiproliferative activities. The most important message from recent investigations is the fact that INFgamma seems to be the main mediator of keratinocyte apoptosis. INFgamma mediates also leukocyte chemotaxis, and enhances the expression of adhesion molecules involved in the pathophysiology of chronic venous insufficiency. Therapeutic injections of interferons can result in skin necrosis. If it were proven that INFgamma was responsible for the development of venous leg ulcers, this fact would have important clinical consequences. In such a case, anti-INFgamma agent could be used, either in the management of active ulceration, or in the prevention of recurrent ulcer.