Chronic proliferative hepatitis in A/JCr mice associated with persistent Helicobacter hepaticus infection: a model of helicobacter-induced carcinogenesis

Helicobacter hepaticus augmentation triggers Dopaminergic degeneration and motor disorders in mice with Parkinson's disease

Gut dysbiosis contributes to Parkinson's disease (PD) pathogenesis. Gastrointestinal disturbances in PD patients, along with gut leakage and intestinal inflammation, take place long before motor disorders. However, it remains unknown what bacterial species in gut microbiomes play the key role in driving PD pathogenesis. Here we show that Helicobacter hepaticus (H. hepaticus), abundant in gut microbiota from rotenone-treated human α-Synuclein gene (SNCA) transgenic mice and PD patients, initiates α-Synuclein pathology and motor deficits in an AEP-dependent manner in SNCA mice. Chronic Dextran sodium sulfate (DSS) treatment, an inflammatory inducer in the gut, activates AEP (asparagine endopeptidase) that cleaves α-Synuclein N103 and triggers its aggregation, promoting inflammation in the gut and the brain and motor defects in SNCA mice. PD fecal microbiota transplant or live H. hepaticus administration into antibiotics cocktail (Abx)-pretreated SNCA mice induces α-Synuclein pathology, inflammation in the gut and brain, and motor dysfunctions, for which AEP is indispensable. Hence, Helicobacter hepaticus enriched in PD gut microbiomes may facilitate α-Synuclein pathologies and motor impairments via activating AEP.

Validation of Multiplex PCR and Serology Detecting Helicobacter Species in Mice

High-throughput multiplexed assays are needed to simplify detection of Helicobacter species in experimental infection and routine health monitoring of laboratory mice. Therefore, fluorescent bead-based hybridization assays for Helicobacter sp. DNA and serology were developed. Multiplex PCR amplicons (H. hepaticus, H. bilis, H. typhlonius, H. pylori, H. muridarum, H. pullorum, H. cinaedi, H. heilmanii, C. jejuni) and antibodies against H. pylori, H. hepaticus, H. bilis were assessed in naturally and experimentally infected mice, and results compared to conventional PCR. Species-specific and sensitive detection of seven Helicobacter spp. <100 copies/PCR, and of two species <1000 copies/PCR was successfully established in the Helicobacter multiplex DNA finder. The novel assay was highly comparable with conventional PCR (kappa = 0.98, 95%CI: 0.94-1.00). Antibody detection of H. hepaticus and H. bilis showed low sensitivity (71% and 62%, respectively) and cross-reactivity in H. typhlonius-infected mice. Infection experiments showed that antibodies develop earliest two weeks after DNA detection in feces. In conclusion, detection of Helicobacter antibodies showed low sensitivity depending on the timing relative to infection. However, Helicobacter multiplex DNA finder is a sensitive and specific high-throughput assay applicable in routine health monitoring for laboratory animals.

Apoptosis triggered by cytolethal distending toxin B subunit of Helicobacter hepaticus is aggravated by autophagy inhibition in mouse hepatocytes

Hepatocytes injury caused by cytolethal distending toxin (CDT) are major events during helicobacter hepaticus (H.hepaticus) infection. Recent study showed that pre-survival autophagy was promoted against CdtB subunit induced DNA damage. In the present study, we demonstrated that inflammatory cytokines IL-6, IL-1β, TNF-α, IFN-α, IFN-γ expression and STAT phosphorylation were promoted by CdtB. Besides, CdtB decreased cell viability while promote apoptosis in mouse liver (AML12) cells. Especially, apoptotic protein caspase-9, caspase-3 and PARP were activated while the ratio of Bcl-2/Bax was decreased after CdtB treatment. Moreover, apoptosis induced by CdtB was inhibited due to Erk/p38 MAPK signaling pathway suppression performed with SB203580 or U0126. Meanwhile, we found that CdtB increased autophagic marker levels accompanied by Akt/mTOR/P70S6K signaling pathway in a dose dependent manner. To assess the correlation between autophagy and apoptosis induced by H.hepaticus, chloroquine (CQ, 50 μM) was employed to inhibit autophagy. The result showed that inhibition of autophagy with CQ treatment promoted apoptosis induced by CdtB. Altogether, all these results suggest that CdtB triggers apoptosis via MAPK/Erk/p38 signaling pathway in caspase dependent manner, which was prevented by autophagy in AML12 cells. Collectively, our findings provide new insights into the virulence potential of CdtB on the molecular pathogenesis throughout H.hepaticus infection.

Helicobacter hepaticus Infection Promotes the Progression of Liver Preneoplasia in BALB/c Mice via the Activation and Accumulation of High-Mobility Group Box-1

It has been documented that Helicobacter hepaticus (H. hepaticus) infection is linked to chronic hepatitis and fibrosis in male BALB/c mice. However, the mechanism underlying the mice model of H. hepaticus–induced hepatocellular carcinoma is not fully known. In this study, male BALB/c mice were infected with H. hepaticus for 3, 6, 12, and 18 months. H. hepaticus colonization, histopathology, expression of proinflammatory cytokines, key signaling pathways, and protein downstream high-mobility group box-1 (HMGB1) in the liver were examined. Our data suggested that the H. hepaticus colonization level in the colon and liver progressively increased over the duration of the infection. H. hepaticus–induced hepatic inflammation and fibrosis were aggravated during the infection, and hepatic preneoplasia developed in the liver of infected mice at 12 and 18 months post-inoculation (MPI). H. hepaticus infection increased the levels of alanine aminotransferase and aspartate aminotransferase in the infected mice. In addition, the mRNA levels of IL-6, Tnf-α, Tgf-β, and HMGB1 were significantly elevated in the liver of H. hepaticus–infected mice from 3 to 18 MPI as compared to the controls. In addition, Ki67 was increased throughout the duration of the infection. Furthermore, HMGB1 protein was activated and translocated from the nucleus to the cytoplasm in the hepatocytes and activated the proteins of signal transducers and activators of transcription 3 (Stat3) and mitogen-activated protein kinase (MAPK) [extracellular regulated protein kinases 1/2 (Erk1/2) and mitogen-activated protein kinase p38 (p38)] upon H. hepaticus infection. In conclusions, these data demonstrated that male BALB/c mice infected with H. hepaticus are prone to suffering hepatitis and developing into hepatic preneoplasia. To verify the effect of HMGB1 in the progression of liver preneoplasia, mice were infected by H. hepaticus for 2 months before additional HMGB1 recombinant adenovirus treatment. All mice were sacrificed at 4 MPI, and the sera and liver tissues from all of the mice were collected. Immunology and histopathology evaluation showed that HMGB1 knockdown attenuated the H. hepaticus–induced hepatic and fibrosis at 4 MPI. Therefore, we showed that H. hepaticus–induced liver preneoplasia is closely correlated with the activation and accumulation of HMGB1.

Helicobacter hepaticus is required for immune targeting of bacterial heat shock protein 60 and fatal colitis in mice

Gut microbiota and the immune system are in constant exchange shaping both host immunity and microbial communities. Here, improper immune regulation can cause inflammatory bowel disease (IBD) and colitis. Antibody therapies blocking signaling through the CD40-CD40L axis showed promising results as these molecules are deregulated in certain IBD patients. To better understand the mechanism, we used transgenic DC-LMP1/CD40 animals with a constitutive CD40-signal in CD11c⁺ cells, causing a lack of intestinal CD103⁺ dendritic cells (DCs) and failure to induce regulatory T (iTreg) cells. These mice rapidly develop spontaneous fatal colitis, accompanied by dysbiosis and increased inflammatory IL-17⁺IFN-γ⁺ Th17/Th1 and IFN-γ ⁺ Th1 cells. In the present study, we analyzed the impact of the microbiota on disease development and detected elevated IgA- and IgG-levels in sera from DC-LMP1/CD40 animals. Their serum antibodies specifically bound intestinal bacteria, and by proteome analysis, we identified a 60 kDa chaperonin GroEL (Hsp60) from Helicobacter hepaticus (Hh) as the main specific antigen targeted in the absence of iTregs. When re-derived to a different Hh-free specific-pathogen-free (SPF) microbiota, mice showed few signs of disease, normal microbiota, and no fatality. Upon recolonization of mice with Hh, the disease developed rapidly. Thus, the present work identifies GroEL/Hsp60 as a major Hh-antigen and its role in disease onset, progression, and outcome in this colitis model. Our results highlight the importance of CD103⁺ DC- and iTreg-mediated immune tolerance to specific pathobionts to maintain healthy intestinal balance.

From DNA Damage to Cancer Progression: Potential Effects of Cytolethal Distending Toxin

Cytolethal distending toxin (CDT), one of the most important genotoxins, is produced by several gram-negative bacteria and is involved in bacterial pathogenesis. Recent studies have shown that bacteria producing this peculiar genotoxin target host DNA, which potentially contributes to development of cancer. In this review, we highlighted the recent studies focusing on the idea that CDT leads to DNA damage, and the cells with inappropriately repaired DNA continue cycling, resulting in cancer development. Understanding the detailed mechanisms of genotoxins that cause DNA damage might be useful for targeting potential markers that drive cancer progression and help to discover new therapeutic strategies to prevent diseases caused by pathogens.

Helicobacters and cancer, not only gastric cancer?

The Helicobacter genus actually comprises 46 validly published species divided into two main clades: gastric and enterohepatic Helicobacters. These bacteria colonize alternative sites of the digestive system in animals and humans, and contribute to inflammation and cancers. In humans, Helicobacter infection is mainly related to H. pylori, a gastric pathogen infecting more than half of the world's population, leading to chronic inflammation of the gastric mucosa that can evolve into two types of gastric cancers: gastric adenocarcinomas and gastric MALT lymphoma. In addition, H. pylori but also non-H. pylori Helicobacter infection has been associated with many extra-gastric malignancies. This review focuses on H. pylori and its role in gastric cancers and extra-gastric diseases, as well as malignancies induced by non-H. pylori Helicobacters. Their different virulence factors and their involvement in carcinogenesis is discussed. This review highlights the importance of both gastric and enterohepatic Helicobacters in gastrointestinal and liver cancers.

Enterohepatic Helicobacter species - clinical importance, host range, and zoonotic potential

The genus Helicobacter defined just over 30 years ago, is a highly diverse and fast-growing group of bacteria that are able to persistently colonize a wide range of animals. The members of this genus are subdivided into two groups with different ecological niches, associated pathologies, and phylogenetic relationships: the gastric Helicobacter (GH) and the enterohepatic Helicobacter (EHH) species. Although GH have been mostly studied, EHH species have become increasingly important as emerging human pathogens and potential zoonotic agents in the last years. This group of bacteria has been associated with the development of several diseases in humans from acute pathologies like gastroenteritis to chronic pathologies that include inflammatory bowel disease, and liver and gallbladder diseases. However, their reservoirs, as well as their routes of transmission, have not been well established yet. Therefore, this review summarizes the current knowledge of taxonomy, epidemiology, and clinical role of the EHH group.

Helicobacter hepaticus infection induces chronic hepatitis and fibrosis in male BALB/c mice via the activation of NF-κB, Stat3, and MAPK signaling pathways

BACKGROUND

It has been documented that Helicobacter hepaticus (H hepaticus) infection is linked to chronic hepatitis and liver cancer. However, our understanding of the molecular mechanisms underlying progression of the H hepaticus-induced hepatic inflammation to cellular hepatocarcinoma is still limited.

MATERIALS AND METHODS

In our study, male BALB/c mice were infected by H hepaticus for 8, 12, 16, 20, and 24 weeks. Histopathology, H hepaticus colonization dynamics, select signaling pathways, and expression of key inflammatory cytokines in the liver were examined.

RESULTS

We found that H hepaticus was detectible in feces of mice at 7 days postinfection (DPI) by PCR, but it was not detected in the livers by PCR until 8 weeks postinfection (WPI). In addition, abundance of colonic and hepatic H hepaticus was progressively increased over the infection duration. H hepaticus-induced hepatic inflammation and fibrosis were aggravated over the infection duration, and necrosis or cirrhosis developed in the infected liver at 24 WPI H hepaticus infection increased levels of alanine aminotransferase and aspartate aminotransferase. Moreover, mRNA levels of Il-6 and Tnf-α were significantly elevated in the livers of H hepaticus-infected mice compared to uninfected control from 8 WPI to 24 WPI. Furthermore, Stat3, nuclear factor-κB (p65), and MAPK (Erk1/2 and p38) were activated by H hepaticus infection.

CONCLUSIONS

These data demonstrated that male BALB/c mice can be used as a new mouse model of H hepaticus-induced liver diseases and that the H hepaticus-induced liver injury is triggered by NF-κB, Jak-Stat, and MAPK signaling pathways.

Bacterial Diseases

Common marmosets are susceptible to a number of bacterial infections, which may be enzootic, causing sporadic but occasionally severe disease, or which may result in epizootics associated with more severe colony morbidity and mortality. The spectrum of these diseases often differs from those observed in macaque species, and veterinarians caring for common marmosets need to be aware of these unique susceptibilities. In formulating differential diagnoses for sick or diseased animals, it should be recognized that diseases once common in imported animals in the 1960s and 1970s are now rare. It is also important to recognize that housing and sanitation conditions can influence exposure to potentially pathogenic bacteria. In a zoological setting where mixed- or free-ranging exhibits are utilized, animals may be exposed to many more potential pathogens than would be the case in animals raised in a barrier facility.

Gamma-glutamyltranspeptidase expression by Helicobacter saguini, an enterohepatic Helicobacter species isolated from cotton top tamarins with chronic colitis

BACKGROUND

Helicobacter saguini is a novel enterohepatic Helicobacter species isolated from captive cotton top tamarins with chronic colitis and colon cancer. Monoassociated H. saguini infection in gnotobiotic IL-10^-/- mice causes typhlocolitis and dysplasia; however, the virulent mechanisms of this species are unknown. Gamma-glutamyltranspeptidase (GGT) is an enzymatic virulence factor expressed by pathogenic Helicobacter and Campylobacter species that inhibits host cellular proliferation and promotes inflammatory-mediated gastrointestinal pathology. The aim of this study was to determine if H. saguini expresses an enzymatically active GGT homologue with virulence properties.

EXPERIMENTAL PROCEDURES

Two putative GGT paralogs (HSGGT1 and HSGGT2) identified in the H. saguini genome were bioinformatically analysed to predict enzymatic functionality and virulence potential. An isogenic knockout mutant strain and purified recombinant protein of HSGGT1 were created to study enzymatic activity and virulence properties by in vitro biochemical and cell culture experiments.

RESULTS

Bioinformatic analysis predicted that HSGGT1 has enzymatic functionality and is most similar to the virulent homologue expressed by Helicobacter bilis, whereas HSGGT2 contains putatively inactivating mutations. An isogenic knockout mutant strain and recombinant HSGGT1 protein were successfully created and demonstrated that H. saguini has GGT enzymatic activity. Recombinant HSGGT1 protein and sonicate from wild-type but not mutant H. saguini inhibited gastrointestinal epithelial and lymphocyte cell proliferation without evidence of cell death. The antiproliferative effect by H. saguini sonicate or recombinant HSGGT1 protein could be significantly prevented with glutamine supplementation or the GGT-selective inhibitor acivicin. Recombinant HSGGT1 protein also induced proinflammatory gene expression in colon epithelial cells.

CONCLUSIONS

This study shows that H. saguini may express GGT as a potential virulence factor and supports further in vitro and in vitro studies into how GGT expression by enterohepatic Helicobacter species influences the pathogenesis of gastrointestinal inflammatory diseases.

Western Diet-Induced Dysbiosis in Farnesoid X Receptor Knockout Mice Causes Persistent Hepatic Inflammation after Antibiotic Treatment

Patients who have liver cirrhosis and liver cancer also have reduced farnesoid X receptor (FXR). The current study analyzes the effect of diet through microbiota that affect hepatic inflammation in FXR knockout (KO) mice. Wild-type and FXR KO mice were on a control (CD) or Western diet (WD) for 10 months. In addition, both CD- and WD-fed FXR KO male mice, which had hepatic lymphocyte and neutrophil infiltration, were treated by vancomycin, polymyxin B, and Abx (ampicillin, neomycin, metronidazole, and vancomycin). Mice were subjected to morphological analysis as well as gut microbiota and bile acid profiling. Male WD-fed FXR KO mice had the most severe steatohepatitis. FXR KO also had reduced Firmicutes and increased Proteobacteria, which could be reversed by Abx. In addition, Abx eliminated hepatic neutrophils and lymphocytes in CD-fed, but not WD-fed, FXR KO mice. Proteobacteria and Bacteroidetes persisted in WD-fed FXR KO mice even after Abx treatment. Only polymyxin B could reduce hepatic lymphocytes in WD-fed FXR KO mice. The reduced hepatic inflammation by antibiotics was accompanied by decreased free and conjugated secondary bile acids as well as changes in gut microbiota. Our data revealed that Lactococcus, Lactobacillus, and Coprococcus protect the liver from inflammation.

Helicobacter hepaticus cytolethal distending toxin promotes intestinal carcinogenesis in 129Rag2-deficient mice

Multiple pathogenic Gram-negative bacteria produce the cytolethal distending toxin (CDT) with activity of DNase I; CDT can induce DNA double-strand breaks (DSBs), G2/M cell cycle arrest, and apoptosis in cultured mammalian cells. However, the link of CDT to in vivo tumorigenesis is not fully understood. In this study, 129/SvEv Rag2^-/- mice were gavaged with wild-type Helicobacter hepatics 3B1(Hh) and its isogenic cdtB mutant HhcdtBm7, followed by infection for 10 and 20 weeks (WPI). HhCDT deficiency did not affect cecal colonization levels of HhcdtBm7, but attenuated severity of cecal pathology in HhcdtBm7-infected mice. Of importance, preneoplasic dysplasia was progressed to cancer from 10 to 20 WPI in the Hh-infected mice but not in the HhcdtBm7-infected mice. In addition, the loss of HhCDT significantly dampened transcriptional upregulation of cecal Tnfα and Il-6, but elevated Il-10 mRNA levels when compared to Hh at 10 WPI. Furthermore, the presence of HhCDT increased numbers of lower bowel intestinal γH2AX-positive epithelial cells (a marker of DSBs) at both 10 and 20 WPI and augmented phospho-Stat3 foci⁺ intestinal crypts (activation of Stat3) at 20 WPI. Our findings suggest that CDT promoted Hh carcinogenesis by enhancing DSBs and activation of the Tnfα/Il-6-Stat3 signaling pathway.

Implications of infectious agents on results of animal experiments

Report of the Working Group on Hygiene of the Gesellschaft für Versuchstierkunde–Society for Laboratory Animal Science (GV-SOLAS)

GV-SOLAS Working Group on Hygiene: Werner Nicklas (Chairman), Felix R. Homberger, Brunhilde Illgen-Wilcke, Karin Jacobi, Volker Kraft, Ivo Kunstyr, Michael Mähler, Herbert Meyer & Gabi Pohlmeyer-Esch

Hepatic Temporal Gene Expression Profiling in Helicobacter hepaticus-Infected A/JCr Mice

Helicobacter hepaticus infection of A/JCr mice is a model of infectious liver cancer. We monitored hepatic global gene expression profiles in H. hepaticus infected and control male A/JCr mice at 3 months, 6 months, and 1 year of age using an Affymetrix-based oligonucleotide microarray platform on the premise that a specific genetic expression signature at isolated time points would be indicative of disease status. Model based expression index comparisons generated by dChip yielded consistent profiles of differential gene expression for H. hepaticus infected male mice with progressive liver disease versus uninfected control mice within each age group. Linear discriminant analysis and principal component analysis allowed segregation of mice based on combined age and lesion status, or age alone. Up-regulation of putative tumor markers correlated with advancing hepatocellular dysplasia. Transcriptionally down-regulated genes in mice with liver lesions included those related to peroxisome proliferator, fatty acid, and steroid metabolism pathways. In conclusion, transcriptional profiling of hepatic genes documented gene expression signatures in the livers of H. hepaticus infected male A/JCr mice with chronic progressive hepatitis and preneoplastic liver lesions, complemented the histopathological diagnosis, and suggested molecular targets for the monitoring and intervention of disease progression prior to the onset of hepatocellular neoplasia.

Male Syrian Hamsters Experimentally Infected with Helicobacter spp. of the H. bilis Cluster Develop MALT-Associated Gastrointestinal Lymphomas

BACKGROUND

Aged hamsters naturally infected with novel Helicobacter spp. classified in the H. bilis cluster develop hepatobiliary lesions and typhlocolitis.

METHODS

To determine whether enterohepatic H. spp. contribute to disease, Helicobacter-free hamsters were experimentally infected with H. spp. after suppression of intestinal bacteria by tetracycline treatment of dams and pups. After antibiotic withdrawal, weanlings were gavaged with four H. bilis-like Helicobacter spp. isolated from hamsters or H. bilis ATCC 43879 isolated from human feces and compared to controls (n = 7 per group).

RESULTS

Helicobacter bilis 43879-dosed hamsters were necropsied at 33 weeks postinfection (WPI) due to the lack of detectable infection by fecal PCR; at necropsy, 5 of 7 were weakly PCR positive but lacked intestinal lesions. The remaining hamsters were maintained for ~95 WPI; chronic H. spp. infection in hamsters (6/7) was confirmed by PCR, bacterial culture, fluorescent in situ hybridization, and ELISA. Hamsters had mild-to-moderate typhlitis, and three of the male H. spp.-infected hamsters developed small intestinal lymphoma, in contrast to one control. Of the three lymphomas in H. spp.-infected hamsters, one was a focal ileal mucosa-associated lymphoid tissue (MALT) B-cell lymphoma, while the other two were multicentric small intestinal large B-cell lymphomas involving both the MALT and extra-MALT mucosal sites with lymphoepithelial lesions. The lymphoma in the control hamster was a diffuse small intestinal lymphoma with a mixed population of T and B cells.

CONCLUSIONS

Results suggest persistent H. spp. infection may augment risk for gastrointestinal MALT origin lymphomas. This model is consistent with H. pylori/heilmannii-associated MALT lymphoma in humans and could be further utilized to investigate the mechanisms of intestinal lymphoma development.

Lamellipodin-Deficient Mice: A Model of Rectal Carcinoma

During a survey of clinical rectal prolapse (RP) cases in the mouse population at MIT animal research facilities, a high incidence of RP in the lamellipodin knock-out strain, C57BL/6-Raph1tm1Fbg (Lpd-/-) was documented. Upon further investigation, the Lpd-/- colony was found to be infected with multiple endemic enterohepatic Helicobacter species (EHS). Lpd-/- mice, a transgenic mouse strain produced at MIT, have not previously shown a distinct immune phenotype and are not highly susceptible to other opportunistic infections. Predominantly male Lpd-/- mice with RP exhibited lesions consistent with invasive rectal carcinoma concomitant to clinically evident RP. Multiple inflammatory cytokines, CD11b+Gr1+ myeloid-derived suppressor cell (MDSC) populations, and epithelial cells positive for a DNA damage biomarker, H2AX, were elevated in affected tissue, supporting their role in the neoplastic process. An evaluation of Lpd-/- mice with RP compared to EHS-infected, but clinically normal (CN) Lpd-/- animals indicated that all of these mice exhibit some degree of lower bowel inflammation; however, mice with prolapses had significantly higher degree of focal lesions at the colo-rectal junction. When Helicobacter spp. infections were eliminated in Lpd-/- mice by embryo transfer rederivation, the disease phenotype was abrogated, implicating EHS as a contributing factor in the development of rectal carcinoma. Here we describe lesions in Lpd-/- male mice consistent with a focal inflammation-induced neoplastic transformation and propose this strain as a mouse model of rectal carcinoma.

Helicobacter bilis and Helicobacter trogontum: infectious causes of abortion in sheep

The aim of our study was to determine the association of Helicobacter spp. that had flexispira morphology with ovine abortion, and to understand the importance of these organisms as a cause of ovine abortion in New Zealand. A retrospective diagnostic survey was carried out on laboratory submissions from ovine abortion outbreaks. A comparison was made of the proportion of laboratory submissions where Helicobacter spp. were detected from flocks that had no other agent identified (group A) with a group that had a known cause of abortion identified (group B). This latter group was considered to be a negative control, given the premise that Helicobacter spp. were not causing abortions and that Helicobacter spp. should be present at a lower rate in the group. Where no diagnosis had been made, aborted material was positive for Helicobacter spp. with flexispira morphology in 8 submissions (20%, 8/40) from 5 of the 31 survey farms (16%, 5/31). Helicobacter spp. were not detected in any of the 18 submissions from the 17 control farms (group B). Helicobacter spp. were confirmed by 16S ribosomal RNA sequencing of 3 of the Helicobacter spp. isolated by culture from the livers of aborted sheep fetuses, and 7 of the 8 where samples were positive in a Helicobacter PCR assay. The Helicobacter spp. were identified as Helicobacter trogontum (Flexispira taxon 5 genotype) and Helicobacter bilis (Flexispira taxon 8 genotype). The findings support Helicobacter spp. being a probable causative agent of ovine abortions in New Zealand.

The Cytolethal Distending Toxin Subunit CdtB of Helicobacter Induces a Th17-related and Antimicrobial Signature in Intestinal and Hepatic Cells In Vitro

Enterohepatic Helicobacter species are associated with several digestive diseases. Helicobacter pullorum is an emerging human foodborne pathogen, and Helicobacter hepaticus is a mouse pathogen; both species are associated with intestinal and/or hepatic diseases. They possess virulence factors, such as cytolethal distending toxin (CDT). Data indicate that CDT may be involved in chronic inflammatory responses, via its active subunit, CdtB. The proinflammatory properties of the CdtB of H. pullorum and H. hepaticus were assessed on human intestinal and hepatic epithelial cells in vitro. Interleukin 8 expression was evaluated by using wild-type strains and their corresponding CdtB isogenic mutants and by delivering CdtB directly into the cells. Nuclear factor κB nuclear translocation and transcriptomic characteristics in response to CdtB were also evaluated. The CdtB of these Helicobacter species induced nuclear factor κB nuclear translocation and exhibited proinflammatory properties, mainly the expression of T-helper type 17-related genes and genes encoding antimicrobial products also involved in cancer. The Histidine residue in position 265 of the CdtB catalytic site appeared to play a role in the regulation of most of these genes. As for flagellin or lipopolysaccharides, CdtB also induced expression of inflammation-associated genes related to antimicrobial activity.

Isolation and characterization of a novel Helicobacter species, Helicobacter jaachi sp. nov., from common marmosets (Callithrix jaachus)

Purpose-bred common marmosets from domestic sources housed in a US research facility, and used in multiple drug discovery programmes, were noted to have a high incidence of spontaneous inflammatory bowel disease and sporadic cholecystitis and cholangiohepatitis. Inflammatory infiltrates increased in incidence and severity with age. Because Helicobacter spp. have been linked to gastrointestinal diseases, samples from the gastrointestinal tracts of 39 marmosets were screened for Helicobacter spp. by culture and PCR. Helicobacter spp. were frequently detected in marmosets; 28.2% of the marmosets were positive for a proposed novel species, Helicobacter jaachi sp. nov., by culture, and 48.7% were positive by Helicobacter genus-specific PCR. Seventeen strains of Helicobacter sp. from 11 marmosets were cultured from various gastrointestinal sites. Older animals (age 6-11 years) had a higher helicobacter prevalence rate (57.1%) compared with younger animals (age 3-5 years), which had a 27.2% prevalence rate. Cells of H. jaachi sp. nov. were catalase, urease and oxidase positive and had fusiform morphology, with periplasmic fibres and multiple bipolar, sheathed flagella. All isolates had similar 16S and 23S rRNA sequences, which clustered as representatives of a novel Helicobacter species closely related to 'Helicobacter sanguini' (97%), a species isolated from cotton-top tamarins and 'Helicobacter callitrichis' (96%) isolated previously from the faeces of common marmosets. The whole genome sequence of one of the liver isolates, H. jaachi sp. nov. MIT 09-6949(T), had a 1.9 Mb genome length with a 41 mol% DNA G+C content. The type strain of Helicobacter jaachi sp. nov., MIT 09-6949(T), has been deposited in the BCCM/LMG Bacteria Collection as LMG 28613(T). These findings add to the increasing number of animal species with gastrointestinal disease in which novel enterohepatic Helicobacter spp. have been isolated.

Infection with Helicobacter bilis but not Helicobacter hepaticus was Associated with Extrahepatic Cholangiocarcinoma

BACKGROUND AND AIMS

The biliary tract cancer or cholangiocarcinoma (CCA) represents the sixth leading cause of gastrointestinal tumors in the Western world, and mortality varies across the world, with regions such as Chile, Thailand, Japan, and northeastern India presenting the highest rates. CCA may develop in the bile duct, gallbladder, or ampulla of Vater; and risk factors include obesity, parity, genetic background, geographical and environmental factors. Inflammation induced by bacterial infections might play a role in the pathogenesis of CCA. In this work, we investigated whether there is an association between extrahepatic cholangiocarcinoma (ECCA) and infection with S. typhi, H. hepaticus, or H. bilis in a Mexican population.

METHODS

A total of 194 patients were included and divided into 91 patients with benign biliary pathology (controls) and 103 with ECCA (cases). Tumor samples were taken during endoscopic retrograde cholangiopancreatography by biliary brushing, followed by DNA extraction and PCR testing for infections.

RESULTS

We found that 44/103 cases were positive for H. bilis, compared with 19/91 controls (p = 0.002; OR 2.83, 95% CI 1.49-5.32), and when analyzed by sub-site, H. bilis infection was significantly more associated with cancer in the common bile duct (p = 0.0005; OR 3.56, 95% CI 1.77-7.17). In contrast, H. hepaticus infection was not different between cases (17/103) and controls (13/91) (p = 0.82; OR 1.19, 95% CI 0.54-2.60). None of the samples were positive for S. typhi infection.

CONCLUSION

In conclusion, infection with H. bilis but neither H. Hepaticus nor S. typhi was significantly associated with ECCA, particularly with tumors located in the common bile duct.

Co-infection of the Siberian hamster (Phodopus sungorus) with a novel Helicobacter sp. and Campylobacter sp

We report the isolation of a novel helicobacter isolated from the caecum of the Siberian hamster (Phodopus sungorus). Sequence analysis showed 97% sequence similarity to Helicobacter ganmani. In addition, we report the co-infection of these Siberian hamsters with a Campylobacter sp. and a second Helicobacter sp. with 99% sequence similarity to Helicobacter sp. flexispira taxon 8 (Helicobacter bilis), a species isolated previously from patients with bacteraemia. Gross necropsy and histopathology did not reveal any overt pathological lesions of the liver and gastrointestinal tract that could be attributed to the Helicobacter or Campylobacter spp. infections. This is the first helicobacter to be identified in the Siberian hamster and the first report of co-infection of Helicobacter spp. and Campylobacter sp. in asymptomatic Siberian hamsters.

Pathogenicity of Helicobacter ganmani in mice susceptible and resistant to infection with H. hepaticus

Helicobacter spp. are some of the most prevalent bacterial contaminants of laboratory mice. Although abundant data regarding the diseases associated with H. hepaticus infection are available, little is known about the pathogenicity of H. ganmani, which was first isolated in 2001 from the intestines of laboratory mice. The objective of this study was to evaluate the host response to H. ganmani colonization in H. hepaticus disease-resistant C57BL/6 and disease-susceptible A/J and IL10-deficient mice. Mice were inoculated with H. ganmani, H. hepaticus, or Brucella broth. Cecal lesion scores, cecal gene expression, and Helicobacter load were measured at 4 and 90 d after inoculation. At both time points, mice inoculated with H. ganmani had similar or significantly more copies of cecum-associated Helicobacter DNA than did mice inoculated with H. hepaticus. When compared with those of sham-inoculated control mice, cecal lesion scores at 4 and 90 d after inoculation were not significantly greater in H. ganmani-inoculated A/J, C57BL/6, or IL10-deficient mice. Analysis of cecal gene expression demonstrated that H. ganmani infection failed to cause significant elevations of IFNγ in A/J, C57BL/6, or IL10-deficient mice. However, in IL10-deficient mice, H. ganmani infection was associated with a significant increase in the expression of the proinflammatory cytokine IL12/23p40. Although H. ganmani infection in this study failed to induce the typhlitis that is the hallmark of H. hepaticus infection, infection with H. ganmani was associated with alterations in inflammatory cytokines in IL10-deficient mice.

Biology and Diseases of Mice

Today’s laboratory mouse, Mus musculus, has its origins as the ‘house mouse’ of North America and Europe. Beginning with mice bred by mouse fanciers, laboratory stocks (outbred) derived from M. musculus musculus from eastern Europe and M. m. domesticus from western Europe were developed into inbred strains. Since the mid-1980s, additional strains have been developed from Asian mice (M. m. castaneus from Thailand and M. m. molossinus from Japan) and from M. spretus which originated from the western Mediterranean region.

Microbiological Quality Control for Laboratory Rodents and Lagomorphs

Mice (Mus musculus), rats (Rattus norvegicus), other rodent species, and domestic rabbits (Oryctolagus cuniculus) have been used in research for over 100 years. During the first half of the 20th century, microbiological quality control of lab animals was at best rudimentary as colonies were conventionally housed and little or no diagnostic testing was done. Hence, animal studies were often curtailed and confounded by infectious disease (Mobraaten and Sharp, 1999; Morse, 2007; Weisbroth, 1999). By the 1950s, it became apparent to veterinarians in the nascent field of comparative medicine that disease-free animals suitable for research could not be produced by standard veterinary disease control measures (e.g., improved sanitation and nutrition, antimicrobial treatments) in conventional facilities. Henry Foster, the veterinarian who founded Charles River Breeding Laboratories in 1948 and a pioneer in the large-scale production of laboratory rodents, stated in a seminar presented at the 30th anniversary of AALAS, “After a variety of frustrating health-related problems, it was decided that a major change in the company’s philosophy was required and an entirely different approach was essential”. Consequently, he and others developed innovative biosecurity systems to eliminate and exclude pathogens (Allen, 1999). In 1958, Foster reported on the Cesarean-originated barrier-sustained (COBS) process for the large-scale production of specific pathogen-free (SPF) laboratory rodents (Foster, 1958). To eliminate horizontally transmitted pathogens, a hysterectomy was performed on a near-term dam from a contaminated or conventionally housed colony. The gravid uterus was pulled through a disinfectant solution into a sterile flexible film isolator where the pups were removed from the uterus and suckled on axenic (i.e., germ-free) foster dams. After being mated to expand their number and associated with a cocktail of nonpathogenic bacteria to normalize their physiology and prime their immune system, rederived rodents were transferred to so-called barrier rooms for large-scale production. The room-level barrier to adventitious infection entailed disinfection of the room, equipment, and supplies, limiting access to trained and properly gowned personnel, and the application of new technologies such as high-efficiency particulate air-filtration of incoming air (Dubos and Schaedler, 1960; Foster, 1980; Schaedler and Orcutt, 1983; Trexler and Orcutt, 1999). The axenic and associated rodents mentioned in the COBS process are collectively classified as gnotobiotic to indicate that they have a completely known microflora. By contrast, barrier-reared rodent colonies are not gnotobiotic because they are housed in uncovered cages and thus acquire a complex microflora from the environment, supplies, personnel, and other sources. Instead, they are described as SPF to indicate that according to laboratory testing, they are free from infection with a defined list of infectious agents, commonly known as an ‘exclusion’ list.

Prevalence of helicobacter in laboratory mice in Thailand

Prevalence of Helicobacter is mostly unknown in laboratory animals in Thailand. The 221 mice feces/cecum from 8 universities, 2 pharmaceutical companies and 3 research institutions in Thailand were surveyed for the prevalence and distribution of Helicobacter species by using the Electrochemical DNA chip. Helicobacter were detected 23/46 samples in Specific Pathogen Free (SPF) and 168/175 in conventional condition. Prevalence of Helicobacter were 98%, 96%, 92% and 78% in South (n=40), Northeast (n=40), North (n=25) and Central area (n=116), respectively. Only Central area holds SPF facility resulting in Helicobacter prevalence that seems to be lower than other areas. Three species of Helicobacter were detected in feces/cecum samples by sequence analysis: H. rodentium (67.0%, 148 samples), Helicobacter sp. MIT 01-6451 (15.4%, 34 samples), and unidentified Helicobacter species (14.1%, 9 samples). The results suggested that H. rodentium is the most common species of Helicobacter in laboratory mice in Thailand.

Helicobacter hepaticus infection promotes hepatitis and preneoplastic foci in farnesoid X receptor (FXR) deficient mice

Farnesoid X receptor (FXR) is a nuclear receptor that regulates bile acid metabolism and transport. Mice lacking expression of FXR (FXR KO) have a high incidence of foci of cellular alterations (FCA) and liver tumors. Here, we report that Helicobacter hepaticus infection is necessary for the development of increased hepatitis scores and FCA in previously Helicobacter-free FXR KO mice. FXR KO and wild-type (WT) mice were sham-treated or orally inoculated with H. hepaticus. At 12 months post-infection, mice were euthanized and liver pathology, gene expression, and the cecal microbiome were analyzed. H. hepaticus induced significant increases hepatitis scores and FCA numbers in FXR KO mice (P<0.01 and P<0.05, respectively). H. hepaticus altered the beta diversity of cecal microbiome in both WT and FXR KO mice compared to uninfected mice (P<0.05). Significant upregulation of β-catenin, Rela, Slc10a1, Tlr2, Nos2, Vdr, and Cyp3a11 was observed in all FXR KO mice compared to controls (P<0.05). Importantly, H. hepaticus and FXR deficiency were necessary to significantly upregulate Cyp2b10 (P<0.01). FXR deficiency was also a potent modulator of the cecal microbiota, as observed by a strong decrease in alpha diversity. A significant decrease in Firmicutes, particularly members of the order Clostridiales, was observed in FXR KO mice (P<0.05 and FDR<5%, ANOVA). While FXR deficiency strongly affects expression of genes related to immunity and bile acid metabolism, as well as the composition of the microbiome; however, its deficiency was not able to produce significant histopathological changes in the absence of H. hepaticus infection.

Helicobacter hepaticus cholesterol-α-glucosyltransferase is essential for establishing colonization in male A/JCr mice

BACKGROUND

Helicobacter pylori cholesterol-α-glucosyltransferase (cgt) is essential for survival of H. pylori in mice. Enterohepatic H. hepaticus, the cause of colonic and hepatocellular carcinoma in susceptible mouse strains, contains an ortholog of the H. pylori cgt. However, the role of cgt in the pathogenesis of H. hepaticus has not been investigated.

MATERIALS AND METHODS

Two cgt-deficient isogenic mutants of wild-type H. hepaticus (WT) 3B1 were generated and used to inoculate male A/JCr mice. Cecal and hepatic colonization levels of the mutants and WT 3B1 as well as select inflammation-associated cytokines were measured by qPCR at 4 months postinoculation.

RESULTS

Both mutants were undetectable in the cecum of any inoculated mice (10 per mutant) but were detected in two livers (one for each mutant); by contrast, 9 and 7 of 10 mice inoculated with WT 3B1 were qPCR positive in the ceca and livers, respectively. The mice inoculated with the mutants developed significantly less severe hepatic inflammation (p < .05) and also produced significantly lower hepatic mRNA levels of proinflammatory cytokines Ifn-γ (p < .01) and Tnf-α (p ≤ .02) as well as anti-inflammatory factors Il10 and Foxp3 compared with the WT 3B1-inoculated mice. Additionally, the WT 3B1-inoculated mice developed significantly higher Th1-associated IgG2a (p < .0001) and Th2-associated IgG1 responses (p < .0001) to H. hepaticus infection than mice dosed with isogenic cgt mutants.

CONCLUSION

Our data indicate that the cholesterol-α-glucosyltransferase is required for establishing colonization of the intestine and liver and therefore plays a critical role in the pathogenesis of H. hepaticus.

Helicobacter hepaticus induces an inflammatory response in primary human hepatocytes

Helicobacter hepaticus can lead to chronic hepatitis and hepatocellular carcinoma in certain strains of mice. Until now the pathogenic role of Helicobacter species on human liver tissue is still not clarified though Helicobacter species identification in human liver cancer was successful in case controlled studies. Therefore we established an in vitro model to investigate the interaction of primary human hepatocytes (PHH) with Helicobacter hepaticus. Successful co-culturing of PHH with Helicobacter hepaticus was confirmed by visualization of motile bacteria by two-photon-microscopy. Isolated human monocytes were stimulated with PHH conditioned media. Changes in mRNA expression of acute phase cytokines and proteins in PHH and stimulated monocytes were determined by Real-time PCR. Furthermore, cytokines and proteins were analyzed in PHH culture supernatants by ELISA. Co-cultivation with Helicobacter hepaticus induced mRNA expression of Interleukin-1 beta (IL-1β), Tumor necrosis factor-alpha, Interleukin-8 (IL-8) and Monocyte chemotactic protein-1 (MCP-1) in PHH (p<0.05) resulting in a corresponding increase of IL-8 and MCP-1 concentrations in PHH supernatants (p<0.05). IL-8 and IL-1β mRNA expression was induced in monocytes stimulated with Helicobacter hepaticus infected PHH conditioned media (p<0.05). An increase of Cyclooxygenase-2 mRNA expression was observed, with a concomitant increase of prostaglandin E2 concentration in PHH supernatants at 24 and 48 h (p<0.05). In contrast, at day 7 of co-culture, no persistent elevation of cytokine mRNA could be detected. High expression of intercellular adhesion molecule-1 on PHH cell membranes after co-culture was shown by two-photon-microscopy and confirmed by flow-cytomety. Finally, expression of Cytochrome P450 3A4 and albumin mRNA were downregulated, indicating an impairment of hepatocyte synthesis function by Helicobacter hepaticus presence. This is the first in vitro model demonstrating a pathogenic effect of a Helicobacter spp. on human liver cells, resulting in an inflammatory response with increased synthesis of inflammatory mediators and consecutive monocyte activation.

Pathogenic properties of enterohepatic Helicobacter spp. isolated from rhesus macaques with intestinal adenocarcinoma

Considerable progress has been made in understanding the roles of Helicobacter pylori in inflammation and gastric cancer; however, far less is known about the roles of enterohepatic Helicobacter species (EHS) in carcinogenesis and their zoonotic or pathogenic potential. We determined the prevalence of EHS infection in a cohort of geriatric rhesus monkeys in which intestinal adenocarcinoma (IAC) is common and investigated the association between EHS infection and IAC. The cohort consisted of 36 animals, 14 of which (age 26-35 years) had IAC. Of the 36 rhesus, 35 (97%) were positive for EHS using PCR or bacterial isolation from faeces, colonic or tumour tissues. Only a single rhesus, which had IAC, was negative for EHS by all detection methods. The EHS identified by 16S rRNA sequencing in this study were from three Helicobacter taxa: Helicobacter macacae (previously rhesus monkey taxon 1), Helicobacter sp. rhesus monkey taxon 2, previously described from strain MIT 99-5507, and Helicobacter sp. rhesus monkey taxon 4, related to Helicobacter fennelliae. Thirteen of 14 monkeys with IAC were positive for either H. macacae (7/13, 54%), EHS rhesus monkey taxon 4 (4/13, 31%) or a mixture of the two EHS (2/13, 15%). These results indicate that EHS are prevalent among aged rhesus macaques with IAC. Using Helicobacter genus-specific florescent in situ hybridization, EHS were detected on the surface of colonic epithelia of infected monkeys. All Helicobacter isolates, including H. macacae, effectively adhered to, invaded, and significantly induced proinflammatory genes, including IL-8, IL-6, TNF-α and iNOS, while downregulating genes involved in the function of inflammasomes, particularly IL-1β, CASPASE-1, NRLP3, NLRP6 and NLRC4 in the human colonic T84 cell line (P<0.0001). These results suggest that EHS may represent an aetiological agent mediating diarrhoea, chronic inflammation, and possibly intestinal cancer in non-human primates, and may play a role in similar disease syndromes in humans. Downregulation of inflammasome function may represent an EHS strategy for long-term persistence in the host and play a role in inducing pathological changes in the host's lower bowel.

Helicobacter species infection may be associated with cholangiocarcinoma: a meta-analysis

OBJECTIVE

Since the discovery of Helicobacter species in human biliary system, the association between Helicobacter species infection and cholangiocarcinoma is under debate. This meta-analysis aims to explore this issue.

METHODS

Literature search was carried out to identify all eligible articles. We performed overall meta-analysis of all included studies and subgroup analysis based on regional distribution. Subgroup analysis in the light of detection methods and specimens was also conducted.

RESULTS

Ten case-control studies were included. Overall meta-analysis favoured a significant association between Helicobacter species infection and cholangiocarcinoma (cumulative OR 8.88, 95% CI 3.67-21.49). Subgroup analysis based on geographic distribution indicated that Helicobacter species infection may serve as a risk factor not only in a region with high cholangiocarcinoma incidence (Asia, OR 6.68, 95% CI 2.29-19.49) but also in low incidence region (Europe, OR 14.90, 95% CI 4.79-46.35). The other subgroup analysis showed that PCR was the most effective and efficient method to detect Helicobacter species in surgically resected tissue and bile. There was significant heterogeneity among studies and obvious publication bias.

CONCLUSION

Our meta-analysis supports the possible association between Helicobacter species infection and cholangiocarcinoma. Further investigations are required to clarify the role of Helicobacter species in this malignancy.

Helicobacter canis colonization in sheep: a Zoonotic link

BACKGROUND

Helicobacter canis has been associated with hepatobiliary and gastrointestinal disease in dogs, cats, and humans. Infection has not been documented in other species.

MATERIALS AND METHODS

Sheep feces subjected to microaerobic culture. Isolates were characterized by genus-specific PCR, restriction fragment length polymorphism, biochemical profiling, and 16S rRNA sequence analysis.

RESULTS

Helicobacter canis was isolated from sheep feces and confirmed by the above methods. These isolates are distinct from other sheep-origin enterohepatic Helicobacter species previously isolated.

CONCLUSIONS

This study identifies sheep as H. canis reservoirs potentially important in zoonotic or foodborne transmission.

Helicobacter pylori infection does not promote hepatocellular cancer in a transgenic mouse model of hepatitis C virus pathogenesis

Helicobacter pylori (H. pylori) and hepatitis C virus (HCV) infect millions of people and can induce cancer. We investigated if H. pylori infection promoted HCV-associated liver cancer. Helicobacter-free C3B6F1 wild-type (WT) and C3B6F1-Tg(Alb1-HCVN)35Sml (HT) male and female mice were orally inoculated with H. pylori SS1 or sterile media. Mice were euthanized at ~12 mo postinoculation and samples were collected for analyses. There were no significant differences in hepatocellular tumor promotion between WT and HT mice; however, HT female mice developed significantly larger livers with more hepatic steatosis than WT female mice. H. pylori did not colonize the liver nor promote hepatocellular tumors in WT or HT mice. In the stomach, H. pylori induced more corpus lesions in WT and HT female mice than in WT and HT male mice, respectively. The increased corpus pathology in WT and HT female mice was associated with decreased gastric H. pylori colonization, increased gastric and hepatic interferon gamma expression, and increased serum Th1 immune responses against H. pylori. HT male mice appeared to be protected from H. pylori-induced corpus lesions. Furthermore, during gastric H. pylori infection, HT male mice were protected from gastric antral lesions and hepatic steatosis relative to WT male mice and these effects were associated with increased serum TNF-α. Our findings indicate that H. pylori is a gastric pathogen that does not promote hepatocellular cancer and suggest that the HCV transgene is associated with amelioration of specific liver and gastric lesions observed during concurrent H. pylori infection in mice.

Helicobacter hepaticus, a new pathogenic species of the Helicobacter genus: Similarities and differences with H. pylori

Helicobacter hepaticus was discovered in 1992 as a cause of liver cancer in the A/JCr mouse model. In susceptible mice, infection by H. hepaticus causes chronic gastrointestinal inflammation leading to neoplasia. It can also cause morphological changes in breast-glands leading to neoplasm and adenocarcinoma in mouse models. Studies performed on humans have revealed that H. hepaticus may also be a human pathogen since infection by H. hepaticus can be associated with cholecystitis, cholelithiasis and gallbladder cancer. H. hepaticus is a close relative of H. pylori, but it lacks the major virulence factors of H. pylori including vacoulating cytotoxin A (VacA) and cytotoxin associated gene (cagA). Moreover, SabA, AlpA, and BabA, three important adhesin proteins of H. pylori, are absent in its genome. In contrast, the genome of H. hepaticus contains genes encoding some orthologus virulence factors of Campylobacter jejuni such as cytolethal distending toxin (CDT), and PebI adhesin factor. Other genes including 16S rRNA, 18 KDa immunogenic protein, and urease structural subunits are related to H. pylori. Its genome contains a small island consisting of 71 Kbp named HHGI1, which probably encodes a secretion system type IV (T4SS), and some other virulence factors. As far as the immunogenic antigens are concerned, the lipopolysaccharide (LPS) and flagellin of H. hepaticus are weak stimulants of the immune system, while pro-inflammatory responses are mainly induced by its lipoproteins and most likely by the peptidoglycan. Concerning the multidrug efflux pumps, a homologue of H. pylori TolC, HefA, has been observed in H. hepaticus which contributes to resistance to amoxicillin and bile acids.

Chemical and cytokine features of innate immunity characterize serum and tissue profiles in inflammatory bowel disease

Inflammatory bowel disease (IBD) arises from inappropriate activation of the mucosal immune system resulting in a state of chronic inflammation with causal links to colon cancer. Helicobacter hepaticus-infected Rag2(-/-) mice emulate many aspects of human IBD, and our recent work using this experimental model highlights the importance of neutrophils in the pathology of colitis. To define molecular mechanisms linking colitis to the identity of disease biomarkers, we performed a translational comparison of protein expression and protein damage products in tissues of mice and human IBD patients. Analysis in inflamed mouse colons identified the neutrophil- and macrophage-derived damage products 3-chlorotyrosine (Cl-Tyr) and 3-nitrotyrosine, both of which increased with disease duration. Analysis also revealed higher Cl-Tyr levels in colon relative to serum in patients with ulcerative colitis and Crohn disease. The DNA chlorination damage product, 5-chloro-2'-deoxycytidine, was quantified in diseased human colon samples and found to be present at levels similar to those in inflamed mouse colons. Multivariate analysis of these markers, together with serum proteins and cytokines, revealed a general signature of activated innate immunity in human IBD. Signatures in ulcerative colitis sera were strongly suggestive of neutrophil activity, and those in Crohn disease and mouse sera were suggestive of both macrophage and neutrophil activity. These data point to innate immunity as a major determinant of serum and tissue profiles and provide insight into IBD disease processes.

Infections of Helicobacter spp. in the biliary system are associated with biliary tract cancer: a meta-analysis

OBJECTIVE

As Helicobacter spp. have been successfully isolated from the biliary system, a hypothetical question was raised about the role of these organisms in the development of biliary tract cancer. This meta-analysis has been carried out to explore the association between Helicobacter spp. infection and biliary tract cancer.

METHODS

A systematic literature search was carried out to identify all eligible articles. Meta-analysis used odds ratio and a random-effect model, and 95% confidence intervals for odds ratios were calculated. Heterogeneity was quantitatively assessed using the χ-test, with significance set at a P-value of 0.01, and was measured using the I-statistic.

RESULTS

Ten studies published between 2002 and 2011 were finally included for meta-analysis. Helicobacter pylori, Helicobacter bilis, Helicobacter hepaticus, and Helicobacter ganmani were studied. With heterogeneity (I=0%, P=0.685), a significantly higher pooled infection rate of Helicobacter spp. was observed in the biliary tract cancer group compared with the normal group (P=0.0001) and the benign biliary disease group, respectively (P=0.0001). Studies from East Asia and South Asia showed a higher prevalence of Helicobacter spp. in the malignant group. Evidence supporting the higher presence of Helicobacter spp. in the cancer group was obtained using PCR and immunohistochemical analysis of specimens from bile and biliary tissues.

CONCLUSION

Our meta-analysis suggests a trend of a higher presence of Helicobacter spp. in patients with biliary tract cancers compared with normal controls or those with benign biliary diseases.

Effects of human and porcine bile on the proteome of Helicobacter hepaticus

BACKGROUND

Helicobacter hepaticus colonizes the intestine and liver of mice causing hepatobiliary disorders such as hepatitis and hepatocellular carcinoma, and has also been associated with inflammatory bowel disease in children. In its habitat, H. hepaticus must encounter bile which has potent antibacterial properties. To elucidate virulence and host-specific adaptation mechanisms of H. hepaticus modulated by human or porcine bile, a proteomic study of its response to the two types of bile was performed employing two-dimensional gel electrophoresis (2-DE) and mass spectrometry.

RESULTS

The 2-DE and mass spectrometry analyses of the proteome revealed that 46 proteins of H. hepaticus were differentially expressed in human bile, 18 up-regulated and 28 down-regulated. In the case of porcine bile, 32 proteins were differentially expressed of which 19 were up-regulated, and 13 were down-regulated. Functional classifications revealed that identified proteins participated in various biological functions including stress response, energy metabolism, membrane stability, motility, virulence and colonization. Selected genes were analyzed by RT-PCR to provide internal validation for the proteomic data as well as provide insight into specific expressions of motility, colonization and virulence genes of H. hepaticus in response to human or porcine bile.

CONCLUSIONS

Overall, the data suggested that bile is an important factor that determines virulence, host adaptation, localization and colonization of specific niches within host environment.

Enteric infection with Citrobacter rodentium induces coagulative liver necrosis and hepatic inflammation prior to peak infection and colonic disease

Acute and chronic forms of inflammation are known to affect liver responses and susceptibility to disease and injury. Furthermore, intestinal microbiota has been shown critical in mediating inflammatory host responses in various animal models. Using C. rodentium, a known enteric bacterial pathogen, we examined liver responses to gastrointestinal infection at various stages of disease pathogenesis. For the first time, to our knowledge, we show distinct liver pathology associated with enteric infection with C. rodentium in C57BL/6 mice, characterized by increased inflammation and hepatitis index scores as well as prominent periportal hepatocellular coagulative necrosis indicative of thrombotic ischemic injury in a subset of animals during the early course of C. rodentium pathogenesis. Histologic changes in the liver correlated with serum elevation of liver transaminases, systemic and liver resident cytokines, as well as signal transduction changes prior to peak bacterial colonization and colonic disease. C. rodentium infection in C57BL/6 mice provides a potentially useful model to study acute liver injury and inflammatory stress under conditions of gastrointestinal infection analogous to enteropathogenic E. coli infection in humans.

Gastric Helicobacter spp. in animal models: pathogenesis and modulation by extragastric coinfections

Animal models are used to study complex host, microbial, and environmental influences associated with gastric Helicobacter infection. Evidence that gastric helicobacters are pathogenic in animals first came from ferrets. Felids, nonhuman primates, and many other species also harbor stomach helicobacters. Today, mice are preferred by most researchers for scientific investigation because of cost-efficiencies, rapid reproduction, choice of laboratory reagents, and availability of genetically engineered models. Infection with Helicobacter felis or H. pylori Sydney strain-1 in appropriate mouse strains produces disease with remarkable similarities to H. pylori in humans. Due to recent advances in genetic engineering, in vivo imaging, and system-wide genomics and proteomics, these models will become even more widespread in the future. Recently, it has been shown that extragastric infections can dramatically affect the severity of disease induced by gastric Helicobacter spp. through heterologous immunity. These models provide proof-of-principle for the "African enigma" wherein gastric cancer is underrepresented in low-lying tropical countries with concurrently high H. pylori and internal parasite prevalence. Helicobacter gastritis and carcinogenesis in mouse models may be augmented or ameliorated by other infectious agents depending on the character of the invoked immune response. Knowledge gained from the Human Microbiome Project and other investigations is certain to shed new light on the influence of extragastric bacterial, viral, fungal, and parasitic coinfections on H. pylori-associated peptic ulcer disease and gastric adenocarcinoma.

Serodiagnosis of Helicobacter hepaticus infection in patients with liver and gastrointestinal diseases: western blot analysis and ELISA using a highly specific monoclonal antibody for H. hepaticus antigen

BACKGROUND

Helicobacter hepaticus infection might be associated with liver and biliary tract diseases. To investigate its pathogenic role, the properties of anti-H. hepaticus serum antibody in patients with liver and diseases were elucidated.

METHODS

Serum samples were collected from 166 patients-69 with liver diseases, 38 with upper gastrointestinal diseases, 17 with lower gastrointestinal diseases, 26 with biliary tract diseases, and 16 with pancreas diseases; 30 control sera were obtained from 30 healthy blood donors. Serum samples were analyzed by enzyme-linked immunosorbent assay (ELISA) and western blot using the new monoclonal antibody HR II-51.

RESULTS

Anti-H. hepaticus serum antibody concentrations in patients with liver disease (n = 69) were significantly increased compared with those in other disease groups (p = 0.014 to <0.001). Particularly, liver cirrhosis (n = 19) showed a significantly higher antibody level compared with other liver diseases (n = 50, p = 0.005) and healthy donors (n = 30, p = 0.0005), as well as a higher seroprevalence (68.4%) compared with other liver diseases (p = 0.05) and healthy donors (p = 0.004). Furthermore, the ELISA value in liver cirrhosis (n = 19) was significantly higher than that in patients with hepatitis B virus (HBV)-and/or hepatitis C virus (HCV)-infected chronic hepatitis (n = 15) (0.389 ± 0.084 vs. 0.350 ± 0.084, p = 0.029). However, there was no relationship between the total immunoglobulin concentration and the anti-H. hepaticus antibody level in each liver disease (Spearman's rank correlation coefficient [rs] < 0.225).

CONCLUSIONS

H. hepaticus infection might play a role in the development of liver diseases; in particular, it might increase the risk of the development of HBV- and/or HCV-infected liver diseases.

Serodiagnosis of Helicobacter hepaticus infection in patients with liver and gastrointestinal diseases: western blot analysis and ELISA using a highly specific monoclonal antibody for H. hepaticus antigen

BACKGROUND

Helicobacter hepaticus infection might be associated with liver and biliary tract diseases. To investigate its pathogenic role, the properties of anti-H. hepaticus serum antibody in patients with liver and diseases were elucidated.

METHODS

Serum samples were collected from 166 patients-69 with liver diseases, 38 with upper gastrointestinal diseases, 17 with lower gastrointestinal diseases, 26 with biliary tract diseases, and 16 with pancreas diseases; 30 control sera were obtained from 30 healthy blood donors. Serum samples were analyzed by enzyme-linked immunosorbent assay (ELISA) and western blot using the new monoclonal antibody HR II-51.

RESULTS

Anti-H. hepaticus serum antibody concentrations in patients with liver disease (n = 69) were significantly increased compared with those in other disease groups (p = 0.014 to <0.001). Particularly, liver cirrhosis (n = 19) showed a significantly higher antibody level compared with other liver diseases (n = 50, p = 0.005) and healthy donors (n = 30, p = 0.0005), as well as a higher seroprevalence (68.4%) compared with other liver diseases (p = 0.05) and healthy donors (p = 0.004). Furthermore, the ELISA value in liver cirrhosis (n = 19) was significantly higher than that in patients with hepatitis B virus (HBV)-and/or hepatitis C virus (HCV)-infected chronic hepatitis (n = 15) (0.389 ± 0.084 vs. 0.350 ± 0.084, p = 0.029). However, there was no relationship between the total immunoglobulin concentration and the anti-H. hepaticus antibody level in each liver disease (Spearman's rank correlation coefficient [rs] < 0.225).

CONCLUSIONS

H. hepaticus infection might play a role in the development of liver diseases; in particular, it might increase the risk of the development of HBV- and/or HCV-infected liver diseases.

Lactobacillus reuteri promotes Helicobacter hepaticus-associated typhlocolitis in gnotobiotic B6.129P2-IL-10(tm1Cgn) (IL-10(-/-) ) mice

To model inflammatory bowel disease, we assessed infection with Helicobacter hepaticus 3B1 (ATCC 51449) and a potential probiotic Lactobacillus reuteri (ATCC PTA-6475) in gnotobiotic B6.129P2-IL-10(tm1Cgn) (IL-10(-/-) ) mice. No typhlocolitis developed in germ-free controls (n=21) or in L. reuteri (n=8) or H. hepaticus (n=18) mono-associated mice for 20 weeks post-infection. As positive controls, three specific pathogen-free IL-10(-/-) mice dosed with H. hepaticus developed severe typhlocolitis within 11 weeks. Because L. reuteri PTA-6475 has anti-inflammatory properties in vitro, it was unexpected to observe significant typhlocolitis (P<0·0001) in mice that had been infected with L. reuteri followed in 1 week by H. hepaticus (n=16). The H. hepaticus colonization was not affected through 20 weeks post-infection but L. reuteri colonization was lower in co-infected compared with L. reuteri mono-associated mice at 8-11 weeks post-infection (P<0·05). Typhlocolitis was associated with an increased T helper type 1 serum IgG2c response to H. hepaticus in co-infected mice compared with H. hepaticus mono-associated mice (P<0·005) and similarly, mRNA expression in caecal-colonic tissue was elevated at least twofold for chemokine ligands and pro-inflammatory interleukin-1α (IL-1α), IL-1β, IL-12 receptor, tumour necrosis factor-α and inducible nitric oxide synthase. Anti-inflammatory transforming growth factor-β, lactotransferrin, peptidoglycan recognition proteins, Toll-like receptors 4, 6, 8 and particularly 9 gene expression, were also elevated only in co-infected mice (P<0·05). These data support that the development of typhlocolitis in H. hepaticus-infected IL-10(-/-) mice required co-colonization with other microbiota and in this study, required only L. reuteri. Although the effects other microbiota may have on H. hepaticus virulence properties remain speculative, further investigations using this gnotobiotic model are now possible.

Helicobacter hepaticus infection in mice: models for understanding lower bowel inflammation and cancer

Pioneering work in the 1990s first linked a novel microaerobic bacterium, Helicobacter hepaticus, with chronic active hepatitis and inflammatory bowel disease in several murine models. Targeted H. hepaticus infection experiments subsequently demonstrated its ability to induce colitis, colorectal cancer, and extraintestinal diseases in a number of mouse strains with defects in immune function and/or regulation. H. hepaticus is now widely utilized as a model system to dissect how intestinal microbiota interact with the host to produce both inflammatory and tolerogenic responses. This model has been used to make important advances in understanding factors that regulate both acquired and innate immune response within the intestine. Further, it has been an effective tool to help define the function of regulatory T cells, including their ability to directly inhibit the innate inflammatory response to gut microbiota. The complete genomic sequence of H. hepaticus has advanced the identification of several virulence factors and aided in the elucidation of H. hepaticus pathogenesis. Delineating targets of H. hepaticus virulence factors could facilitate novel approaches to treating microbially induced lower bowel inflammatory diseases.

Ulcerative typhlocolitis associated with Helicobacter mastomyrinus in telomerase-deficient mice

Telomerase deficiency induces early senescence and defects in proliferating cell populations, but in mice it has not been associated with inflammatory bowel disease. Genetically engineered mice lacking either telomerase reverse transcriptase (TERT) or telomerase RNA were examined for chronic diarrhea and wasting. Affected mice had pasty stools, thickened nondistensible colon walls, and contracted ceca. Histologically, the cecal mucosa was largely replaced by inflammatory infiltrate consisting of plasma cells, neutrophils, lymphocytes, and macrophages with marked widespread fibrosis and ulceration. Remaining epithelium was disorganized and hyperplastic, with multifocal dysplasia. Colonic mucosa was markedly hyperplastic with similar inflammation and epithelial dysplasia. Multifocal adenomatous hyperplasia, but no inflammation, was present in the small intestine. Microaerophilic spiral bacteria with 16S rRNA gene sequences identical to Helicobacter mastomyrinus were isolated from the colon and cecum. Severe granulomatous typhlocolitis without epithelial dysplasia developed in germ-free recombination-activating gene (RAG) knockout (KO) recipients of CD4+ T cells and inoculated with cecal contents from affected TERT KO mice and in specific pathogen-free recipient RAG KO mice and interleukin-10 KO mice inoculated with H mastomyrinus. Typhlocolitis in mice given H mastomyrinus was more severe than in mice given Helicobacter hepaticus. Telomerase-deficient mice are susceptible to helicobacter-associated typhlocolitis. H mastomyrinus causes severe disease in susceptible mouse strains.

Persistent infection of rhesus monkeys with 'Helicobacter macacae' and its isolation from an animal with intestinal adenocarcinoma

A novel helicobacter, 'Helicobacter macacae', was previously isolated from a colony of rhesus and cynomolgus monkeys in which diarrhoea from chronic idiopathic colitis was enzootic. A survey performed in a second colony of rhesus monkeys without a history of chronic diarrhoea determined that 57 % were faecal-culture positive for Helicobacter species. Ten years after the survey, one of the animals from which 'H. macacae' had been isolated, a 23-year-old, intact male rhesus monkey (Macaca mulatta), presented with partial inappetence and progressive weight loss. Subsequent evaluation of the monkey revealed anaemia, hypoproteinaemia, hypoalbuminaemia and a palpable abdominal mass. Contrast radiography suggested partial intestinal obstruction. The animal was euthanized and a diagnosis was made of intestinal adenocarcinoma of the ileocaecocolic junction with metastasis to regional lymph nodes and liver. Microaerobic culture of caecal tissue yielded a helicobacter organism identified as 'H. macacae' by 16S rRNA gene sequencing - the same species of bacteria isolated 10 years previously. The liver, small intestine and colon were also positive by PCR for Helicobacter species. Intestinal adenocarcinoma is the most common malignancy of aged macaques. Faeces or caecal tissue from five out of five monkeys that remained from the original cohort and that were colonized with 'H. macacae' in the initial survey were positive for the organism. The apparent persistence of 'H. macacae' in these animals, the isolation of the bacterium from animals with colitis and the recognition of the importance of inflammation in carcinogenesis raise the possibility of an aetiological role in the genesis of intestinal adenocarcinoma in aged rhesus monkeys.

Experimental Helicobacter marmotae infection in A/J mice causes enterohepatic disease

Helicobacter marmotae has been identified in the inflamed livers of Eastern woodchucks (Marmota monax) infected with woodchuck hepatitis virus (WHV), as well as from the livers of WHV-negative woodchucks. Because the majority of WHV-positive woodchucks with hepatic tumours were culture or PCR positive for this helicobacter, and WHV-negative woodchucks with H. marmotae had hepatitis, the bacterium may have a role in tumour promotion related to chronic inflammation. In this study, the type strain of H. marmotae was inoculated intraperitoneally into 48 male and female A/J mice, a strain noted to be susceptible to Helicobacter hepaticus-induced liver tumours. Sixteen mice served as mock-dosed controls. At 6, 12 and 18 months post-inoculation (p.i.), there were statistically significant (P<0.05) differences in mean inflammation scores for the caecum and proximal colon between experimentally infected and control mice. Differences in hepatic inflammation were significant (P<0.05) at 6 and 12 months p.i. between the two groups but not at the 18 month time point. Two infected male mice had livers with severe hepatitis, and the liver samples were culture positive for H. marmotae. Serum IgG levels in the mice dosed with H. marmotae were elevated for the duration of the study. These results demonstrate that the woodchuck helicobacter can successfully colonize mice and cause enterohepatic disease. In the future, a mouse-adapted strain of H. marmotae could be selected to maximize colonization and lesion development. Such a woodchuck helicobacter-infected mouse model could be used to dissect potential mechanisms of microbial co-carcinogenesis involved in tumour development in woodchucks with WHV and in humans with hepatitis B virus.