RESUMEN
BACKGROUND AND AIMS: Hepatocellular carcinoma (HCC) frequently results from synergism between chemical and infectious liver carcinogens. Worldwide, the highest incidence of HCC is in regions endemic for the foodborne contaminant aflatoxin B1 (AFB1) and hepatitis B virus (HBV) infection. Recently, gut microbes have been implicated in multisystemic diseases including obesity and diabetes. Here, the hypothesis that specific intestinal bacteria promote liver cancer was tested in chemical and viral transgenic mouse models. METHODS: Helicobacter-free C3H/HeN mice were inoculated with AFB1 and/or Helicobacter hepaticus. The incidence, multiplicity and surface area of liver tumours were quantitated at 40 weeks. Molecular pathways involved in tumourigenesis were analysed by microarray, quantitative real-time PCR, liquid chromatography/mass spectrometry, ELISA, western blot and immunohistochemistry. In a separate experiment, C57BL/6 FL-N/35 mice harbouring a full-length hepatitis C virus (HCV) transgene were crossed with C3H/HeN mice and cancer rates compared between offspring with and without H hepaticus. RESULTS: Intestinal colonisation by H hepaticus was sufficient to promote aflatoxin- and HCV transgene-induced HCC. Neither bacterial translocation to the liver nor induction of hepatitis was necessary. From its preferred niche in the intestinal mucus layer, H hepaticus activated nuclear factor-kappaB (NF-kappaB)-regulated networks associated with innate and T helper 1 (Th1)-type adaptive immunity both in the lower bowel and liver. Biomarkers indicative of tumour progression included hepatocyte turnover, Wnt/beta-catenin activation and oxidative injury with decreased phagocytic clearance of damaged cells. CONCLUSIONS: Enteric microbiota define HCC risk in mice exposed to carcinogenic chemicals or hepatitis virus transgenes. These results have implications for human liver cancer risk assessment and prevention.
Asunto(s)
Aflatoxina B1/toxicidad , Hepatitis B/complicaciones , Intestinos/microbiología , Neoplasias Hepáticas Experimentales/etiología , Inmunidad Adaptativa , Animales , Proliferación Celular , Transformación Celular Neoplásica/genética , Quimiocinas/sangre , Cocarcinogénesis , Femenino , Infecciones por Helicobacter/complicaciones , Helicobacter hepaticus , Hepatitis B/inmunología , Inmunidad Innata , Subunidad p40 de la Interleucina-12/sangre , Neoplasias Hepáticas Experimentales/microbiología , Masculino , Ratones , Ratones Endogámicos C3H , Ratones Endogámicos C57BL , Ratones Transgénicos , Estrés Oxidativo/fisiología , Factores Sexuales , Transducción de Señal/fisiología , Células TH1/inmunologíaRESUMEN
Helicobacter cinaedi colonizes a wide host range, including rodents, and may be an emerging zoonotic agent. Colonization parameters, pathology, serology, and inflammatory responses to wild-type H. cinaedi (WT(Hc)) were evaluated in B6.129P2-IL-10(tm1Cgn) (IL-10(-/-)) mice for 36 weeks postinfection (WPI) and in C57BL/6 (B6) mice for 12 WPI. Because cytolethal distending toxin (CDT) may be a virulence factor, IL-10(-/-) mice were also infected with the cdtB(Hc) and cdtB-N(Hc) isogenic mutants and evaluated for 12 WPI. Consistent with other murine enterohepatic helicobacters, WT(Hc) did not cause typhlocolitis in B6 mice, but mild to severe lesions developed at the cecocolic junction in IL-10(-/-) mice, despite similar colonization levels of WT(Hc) in the cecum and colon of both B6 and IL-10(-/-) mice. WT(Hc) and cdtB mutants also colonized IL-10(-/-) mice to a similar extent, but infection with either cdtB mutant resulted in attenuated typhlocolitis and hyperplasia compared to infection with WT(Hc) (P < 0.03), and only WT(Hc) infection caused dysplasia and intramucosal carcinoma. WT(Hc) and cdtB(Hc) mutant infection of IL-10(-/-) mice elevated mRNA expression of tumor necrosis factor alpha, inducible nitric oxide synthase, and gamma interferon in the cecum, as well as elevated Th1-associated serum immunoglobulin G2a(b) compared to infection of B6 mice (P < 0.05). Although no hepatitis was noted, liver samples were PCR positive at various time points for WT(Hc) or the cdtB(Hc) mutant in approximately 33% of IL-10(-/-) mice and in 10 to 20% of WT(Hc)-infected B6 mice. These results indicate that WT(Hc) can be used to model inflammatory bowel disease in IL-10(-/-) mice and that CDT contributes to the virulence of H. cinaedi.
Asunto(s)
Toxinas Bacterianas/toxicidad , Colitis/microbiología , Infecciones por Helicobacter/microbiología , Helicobacter/patogenicidad , Interleucina-10/deficiencia , Tiflitis/microbiología , Animales , Toxinas Bacterianas/genética , Colitis/inmunología , Colitis/patología , Femenino , Infecciones por Helicobacter/inmunología , Masculino , Ratones , Ratones Endogámicos C57BL , Tiflitis/inmunología , Tiflitis/patologíaRESUMEN
Recombinase-activating gene-2-deficient (Rag2(-/-)) mice lacking functional lymphocytes provide a useful model of chronic inflammatory bowel disease-emulating events in human colon cancer. Infection of Rag2(-/-) mice with Helicobacter hepaticus led to accumulation of macrophages and neutrophils in the colon, a process temporally related to up-regulation of tissue inducible nitric oxide synthase (iNOS) expression at the site of infection and increased nitric oxide (NO) production, as evidenced by urinary excretion of nitrate. Progressive development of increasingly severe inflammation, hyperplasia, dysplasia, and cancer accompanied these changes. Concurrent administration of an iNOS inhibitor prevented NO production and abrogated epithelial pathology and inhibited the onset of cancer. The presence of Gr-1(+) neutrophils and elevated tumor necrosis factor-alpha (TNF-alpha) expression in colon were required for increased iNOS expression and cancer, whereas interleukin-10 (IL-10) down-regulated TNF-alpha and iNOS expression and suppressed cancer. Anti-inflammatory CD4(+) regulatory lymphocytes also down-regulated iNOS and reduced cancer formation. Collectively, these results confirm essential roles for inflammation, increased TNF-alpha expression, and elevated NO production in colon carcinogenesis.
Asunto(s)
Colon/patología , Neoplasias del Colon/patología , Proteínas de Unión al ADN/deficiencia , Infecciones por Helicobacter/microbiología , Helicobacter hepaticus/inmunología , Óxido Nítrico/metabolismo , Factor de Necrosis Tumoral alfa/metabolismo , Animales , Arginina/farmacología , Colon/enzimología , Colon/inmunología , Colon/microbiología , Neoplasias del Colon/complicaciones , Neoplasias del Colon/inmunología , Neoplasias del Colon/microbiología , Proteínas de Unión al ADN/metabolismo , Inhibidores Enzimáticos/farmacología , Infecciones por Helicobacter/enzimología , Infecciones por Helicobacter/inmunología , Infecciones por Helicobacter/orina , Inflamación/inmunología , Inflamación/microbiología , Mediadores de Inflamación/metabolismo , Ratones , Nitratos/orina , Óxido Nítrico Sintasa de Tipo II/antagonistas & inhibidores , Óxido Nítrico Sintasa de Tipo II/metabolismoRESUMEN
OBJECTIVE: To elucidate the role of methionine aminopeptidase type-2 (MetAP-2) in the clinical pathology of rheumatoid arthritis, arthritis was induced in rats by administration of peptidoglycan-polysaccharide (PG-PS). DESIGN: The inhibitor of MetAP-2, PPI-2458, was administered orally at 5 mg/kg every other day during 3 distinct phases of the disease. In vitro studies were performed to clarify in vivo findings. RESULTS: Ankle swelling was completely alleviated by MetAP-2 inhibition. Inhibition of MetAP-2 in blood and tissues correlated with protection against PG-PS-induced arthritis. Histopathology of the tarsal joints improved following PPI-2458 administration, including a significant improvement of bone structure. In in vitro studies, osteoclast formation and activity were inhibited by PPI-2458, a mechanism not previously attributed to MetAP-2 inhibition. CONCLUSIONS: The important role that MetAP-2 has in the pathophysiological disease processes of PG-PS arthritis provides a strong rationale for evaluating PPI-2458 as a disease modifying antirheumatic treatment for rheumatoid arthritis.
Asunto(s)
Aminopeptidasas/antagonistas & inhibidores , Artritis Reumatoide/tratamiento farmacológico , Compuestos Epoxi/uso terapéutico , Metaloendopeptidasas/antagonistas & inhibidores , Inhibidores de Proteasas/uso terapéutico , Valina/análogos & derivados , Aminopeptidasas/análisis , Animales , Artritis Reumatoide/patología , Peso Corporal/efectos de los fármacos , Resorción Ósea/prevención & control , Diferenciación Celular/efectos de los fármacos , Células Cultivadas , Compuestos Epoxi/farmacología , Femenino , Articulaciones/patología , Metaloendopeptidasas/análisis , Ratones , Osteoclastos/citología , Osteoclastos/efectos de los fármacos , Ratas , Ratas Endogámicas Lew , Valina/farmacología , Valina/uso terapéuticoRESUMEN
Infection with Helicobacter trogontum, a urease-positive helicobacter isolated from subclinically infected rats, was evaluated in B6.129P2-IL10(tm1Cgn) (interleukin-10(-/-) [IL-10(-/-)]) and C57BL/6 (B6) mice. In a first experiment, IL-10(-/-) mice naturally infected with Helicobacter rodentium had subclinical typhlocolitis but developed severe diarrhea and loss of body condition with erosive to ulcerative typhlocolitis within 1 to 3 weeks of experimental infection with H. trogontum. A second experiment demonstrated that helicobacter-free IL-10(-/-) mice dosed with H. trogontum also developed severe clinical signs and typhlocolitis within 2 to 4 weeks, whereas B6 mice colonized with H. trogontum were resistant to disease. In a third experiment, using helicobacter-free IL-10(-/-) mice, dosing with H. trogontum resulted in acute morbidity and typhlocolitis within 8 days. Acute typhlocolitis was accompanied by signs of sepsis supported by degenerative hemograms and recovery of Escherichia coli and Proteus spp. from the livers of infected mice. Quantitative PCR data revealed that H. rodentium and H. trogontum may compete for colonization of the lower bowel, as H. trogontum established higher colonization levels in the absence of H. rodentium (P < 0.003). H. trogontum-induced typhlocolitis was also associated with a significant decrease in the levels of colonization by five of eight anaerobes that comprise altered Schaedler's flora (P < 0.002). These results demonstrate for the first time that H. rodentium infection in IL-10(-/-) mice causes subclinical typhlocolitis and that infection with H. trogontum (with or without H. rodentium) induces a rapid-onset, erosive to ulcerative typhlocolitis which impacts the normal anaerobic flora of the colon and increases the risk of sepsis.
Asunto(s)
Ciego/microbiología , Colitis Ulcerosa/microbiología , Infecciones por Helicobacter/microbiología , Animales , Ciego/patología , Colitis Ulcerosa/inmunología , Colitis Ulcerosa/patología , ADN Bacteriano/análisis , Helicobacter/aislamiento & purificación , Infecciones por Helicobacter/genética , Infecciones por Helicobacter/inmunología , Interleucina-10/genética , Leucocitosis/microbiología , Hígado/microbiología , Masculino , Ratones , Ratones Noqueados , Ratones Mutantes , RatasRESUMEN
Cryptosporidium spp. cause diarrheal disease worldwide. Innate immune responses mediating resistance to this parasite are not completely understood. To determine whether MyD88-dependent pathways play a role in resistance to Cryptosporidium parvum, we compared the course of infection in MyD88(-/-) mice to that in their wild-type (WT) littermate controls. Three- to 4-week-old mice were infected with C. parvum, and infection was monitored by quantifying fecal oocyst shedding. Twelve days postinfection, the histology of the intestines was examined to quantify intestinal parasite burden and to determine if there were any pathological changes. Fecal oocyst shedding and intestinal parasite burden were significantly greater in MyD88(-/-) mice than in littermate controls. Nonetheless, both WT and MyD88(-/-) mice cleared the infection within 3 weeks. These results indicate that MyD88-dependent pathways are involved in mediating initial resistance to C. parvum. Since gamma interferon (IFN-gamma) is known to mediate resistance to C. parvum, we also studied infection in MyD88(-/-) mice and WT controls in which this cytokine was temporarily neutralized. Fecal oocyst shedding, as well as intestinal parasite burden, intestinal inflammation, and mortality, was significantly greater in MyD88(-/-) mice in which IFN-gamma was neutralized than in IFN-gamma-neutralized WT mice or in MyD88(-/-) mice in which this cytokine was active. These results suggest that MyD88 and IFN-gamma had an additive effect in conferring protection from C. parvum infection. While this study confirms the importance of IFN-gamma in conferring resistance to infection with C. parvum, it suggests that MyD88-mediated pathways also play a role in innate immunity to this parasite.
Asunto(s)
Proteínas Adaptadoras Transductoras de Señales/fisiología , Antígenos de Diferenciación/fisiología , Criptosporidiosis/inmunología , Cryptosporidium parvum/inmunología , Receptores Inmunológicos/fisiología , Transducción de Señal/inmunología , Proteínas Adaptadoras Transductoras de Señales/deficiencia , Proteínas Adaptadoras Transductoras de Señales/genética , Animales , Antígenos de Diferenciación/genética , Criptosporidiosis/metabolismo , Criptosporidiosis/mortalidad , Enterocolitis/inmunología , Enterocolitis/metabolismo , Enterocolitis/mortalidad , Enterocolitis/parasitología , Femenino , Inmunidad Innata/genética , Interferón gamma/antagonistas & inhibidores , Interferón gamma/fisiología , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Factor 88 de Diferenciación Mieloide , Receptores Inmunológicos/deficiencia , Receptores Inmunológicos/genética , Transducción de Señal/genéticaRESUMEN
Hepatobiliary disease was diagnosed in eight of 34 genetically unrelated cohabitating pet ferrets (Mustela putorios furo) during a 7-year period. The eight ferrets ranged in age from 5 to 8 years and exhibited chronic cholangiohepatitis coupled with cellular proliferation ranging from hyperplasia to frank neoplasia. Spiral-shaped argyrophilic bacteria were demonstrated in livers of three ferrets, including two with carcinoma. Sequence analysis of a 400-base pair polymerase chain reaction product amplified from DNA derived from fecal bacteria from one ferret demonstrated 98% and 97% similarity to Helicobacter cholecystus and Helicobacter sp. strain 266-1 , respectively. The clustering of severe hepatic disease in these cohabitating ferroes suggests a possible infectious etiology. The role of Helicobacter species and other bacteria in hepatitis and/or neoplasia in ferrets requires further study.
Asunto(s)
Enfermedades de las Vías Biliares/veterinaria , Hurones , Infecciones por Helicobacter/veterinaria , Helicobacter pylori/aislamiento & purificación , Hepatopatías/veterinaria , Animales , Neoplasias de los Conductos Biliares/etiología , Neoplasias de los Conductos Biliares/microbiología , Neoplasias de los Conductos Biliares/patología , Neoplasias de los Conductos Biliares/veterinaria , Conductos Biliares/patología , Enfermedades de las Vías Biliares/microbiología , Enfermedades de las Vías Biliares/patología , Colangiocarcinoma/etiología , Colangiocarcinoma/microbiología , Colangiocarcinoma/patología , Colangiocarcinoma/veterinaria , Cistoadenoma/microbiología , Cistoadenoma/patología , Cistoadenoma/veterinaria , ADN Bacteriano/análisis , Femenino , Infecciones por Helicobacter/complicaciones , Helicobacter pylori/genética , Hepatitis Animal/microbiología , Hepatitis Animal/patología , Hiperplasia/veterinaria , Inmunohistoquímica/veterinaria , Hígado/microbiología , Hepatopatías/microbiología , Hepatopatías/patología , Masculino , Reacción en Cadena de la Polimerasa/veterinariaRESUMEN
OBJECTIVE: To evaluate the immune response induced by Borrelia theileri infection and to determine whether B theileri induces cross-reacting antibodies to other bovine borreliae. ANIMALS: Two 3-month-old calves, 1 of which was splenectomized. PROCEDURE: Calves were exposed to Boophilus microplus infected with B theileri. Rectal temperature, PCV, bacteremia, and clinical signs of infection were monitored. Serum was obtained weekly and used to evaluate the humoral response to homologous antigen and B burgdorferi and B coriaceae, using an indirect fluorescent antibody (IFA) test, and to B burgdorferi, using a commercially available ELISA. The identity of cross-reacting antigens was explored, using monoclonal antibodies to genus- and species-specific antigens in an IFA test. RESULTS: B theileri-infected calves produced antibodies that cross-reacted with B burgdorferi and B coriaceae whole-cell antigens. Borrelia theileri whole-cell antigen was recognized by genus-specific monoclonal antibody H9724 but not by species-specific antibody H5332. False-positive reactions were not observed when serum from B theileri-infected calves was tested by use of the ELISA for B burgdorferi. CONCLUSIONS: B theileri induces humoral responses in infected cattle that can be confused with those of other borrelial infections. Care must be taken to definitively distinguish between the various borreliae that may cause disease in cattle. CLINICAL RELEVANCE: Serologic cross-reactivity must be taken into account when making a serodiagnosis of Lyme borreliosis or epizootic abortion in epidemiologic studies involving cattle.
Asunto(s)
Anticuerpos Antibacterianos/sangre , Infecciones por Borrelia/veterinaria , Grupo Borrelia Burgdorferi/inmunología , Borrelia/inmunología , Enfermedades de los Bovinos/inmunología , Animales , Anticuerpos Antibacterianos/inmunología , Formación de Anticuerpos , Infecciones por Borrelia/sangre , Infecciones por Borrelia/inmunología , Bovinos , Enfermedades de los Bovinos/sangre , Reacciones Cruzadas , Técnica del Anticuerpo Fluorescente Indirecta , Larva , Masculino , Esplenectomía , Garrapatas/microbiologíaRESUMEN
The feline immunodeficiency virus (FIV) model of vertical human immunodeficiency virus type 1 transmission was used to explore the timing and tissue tropisms associated with intrauterine lentivirus infection. Cats chronically infected with FIV-B-2542 and their cesarean-derived fetuses and placentas were assayed by polymerase chain reaction and coculture at defined gestational intervals. Prevalence of fetal FIV infection was 0 at 3 weeks, 5% at 5 weeks, 38% at 7 weeks, and 60% at 9 weeks (term). Fetal tissues exhibiting the highest viral tropism were blood mononuclear cells and brain (each containing virus in 60% of FIV-positive fetuses) and thymus (47%). Maternal hematologic and virus load markers did not vary substantially with gestational stage. Therefore, fetal and/or placental maturation may determine the timing of lentivirus transmission. FIV infection prevalence in term fetuses was equivalent to that seen previously in vaginally delivered offspring, suggesting that most vertical FIV transmission occurs late in utero rather than intrapartum.