RESUMEN
BACKGROUND & AIM: Acetaminophen (APAP)-induced acute liver failure is associated with substantial alterations in the hemostatic system. In mice, platelets accumulate in the liver after APAP overdose and appear to promote liver injury. Interestingly, patients with acute liver injury have highly elevated levels of the platelet-adhesive protein von Willebrand factor (VWF), but a mechanistic connection between VWF and progression of liver injury has not been established. We tested the hypothesis that VWF contributes directly to experimental APAP-induced acute liver injury. METHODS: Wild-type mice and VWF-deficient (Vwf-/-) mice were given a hepatotoxic dose of APAP (300â¯mg/kg, i.p.) or vehicle (saline). VWF plasma levels were measured by ELISA, and liver necrosis or hepatocyte proliferation was measured by immunohistochemistry. Platelet and VWF deposition were measured by immunofluorescence. RESULTS: In wild-type mice, VWF plasma levels, high molecular weight (HMW) VWF multimers, and VWF activity decreased 24â¯h after APAP challenge. These changes coupled to robust hepatic VWF and platelet deposition, although VWF deficiency had minimal effect on peak hepatic platelet accumulation or liver injury. VWF plasma levels were elevated 48â¯h after APAP challenge, but with relative reductions in HMW multimers and VWF activity. Whereas hepatic platelet aggregates persisted in livers of APAP-challenged wild-type mice, platelets were nearly absent in Vwf-/- mice 48â¯h after APAP challenge. The absence of platelet aggregates was linked to dramatically accelerated repair of the injured liver. Complementing observations in Vwf-/- mice, blocking VWF or the platelet integrin αIIbß3 during development of injury significantly reduced hepatic platelet aggregation and accelerated liver repair in APAP-challenged wild-type mice. CONCLUSION: These studies are the first to suggest a mechanistic link between VWF, hepatic platelet accumulation, and liver repair. Targeting VWF might provide a novel therapeutic approach to improve repair of the APAP-injured liver. LAY SUMMARY: Patients with acute liver injury due to acetaminophen overdose have highly elevated levels of the platelet-adhesive protein von Willebrand factor. It is not known whether von Willebrand factor plays a direct role in the progression of acute liver injury. We discovered that von Willebrand factor delays repair of the acetaminophen-injured liver in mice and that targeting von Willebrand factor, even in mice with established liver injury, accelerates liver repair.
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Acetaminofén/efectos adversos , Analgésicos no Narcóticos/efectos adversos , Plaquetas/metabolismo , Enfermedad Hepática Inducida por Sustancias y Drogas/sangre , Enfermedad Hepática Inducida por Sustancias y Drogas/etiología , Hígado/metabolismo , Factor de von Willebrand/metabolismo , Acetaminofén/administración & dosificación , Analgésicos no Narcóticos/administración & dosificación , Animales , Coagulación Sanguínea/efectos de los fármacos , Humanos , Hígado/patología , Masculino , Tasa de Depuración Metabólica , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Necrosis , Agregación Plaquetaria/efectos de los fármacos , Factor de von Willebrand/administración & dosificación , Factor de von Willebrand/genética , Factor de von Willebrand/farmacocinéticaRESUMEN
We examined the effects of two over-the-counter H1-antihistamines on the progression of fatty liver disease in male C57Bl/6 wild-type and apolipoprotein E (ApoE)-/- mice. Mice were fed a high-fat diet (HFD) for 3 mo, together with administration of either cetirizine (4 mg/kg body wt) or fexofenadine (40 mg/kg body wt) in drinking water. Antihistamine treatments increased body weight gain, gonadal fat deposition, liver weight, and hepatic steatosis in wild-type mice but not in ApoE-/- mice. Lobular inflammation, acute inflammation, and necrosis were not affected by H1-antihistamines in either genotype. Serum biomarkers of liver injury tended to increase in antihistamine-treated wild-type mice. Serum level of glucose was increased by fexofenadine, whereas lipase was increased by cetirizine. H1-antihistamines reduced the mRNA expression of ApoE and carbohydrate response element-binding protein in wild-type mice, without altering the mRNA expression of sterol regulatory element-binding protein 1c, fatty acid synthase, or ApoB100, in either genotype. Fexofenadine increased both triglycerides and cholesterol ester, whereas cetirizine increased only cholesterol ester in liver, with a concomitant decrease in serum triglycerides by both antihistamines in wild-type mice. Antihistamines increased hepatic levels of conjugated bile acids in wild-type mice, with the effect being significant in fexofenadine-treated animals. The increase was associated with changes in the expression of organic anion transport polypeptide 1b2 and bile salt export pump. These results suggest that H1-antihistamines increase the progression of fatty liver disease in wild-type mice, and there seems to be an association between the severity of disease, presence of ApoE, and increase in hepatic bile acid levels.
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Apolipoproteínas E/deficiencia , Cetirizina/toxicidad , Dieta Alta en Grasa , Hígado Graso/inducido químicamente , Antagonistas de los Receptores Histamínicos H1/toxicidad , Hígado/efectos de los fármacos , Terfenadina/análogos & derivados , Miembro 11 de la Subfamilia B de Transportador de Casetes de Unión al ATP , Transportadoras de Casetes de Unión a ATP/genética , Transportadoras de Casetes de Unión a ATP/metabolismo , Animales , Apolipoproteínas E/genética , Ácidos y Sales Biliares/metabolismo , Biomarcadores/sangre , Ésteres del Colesterol/metabolismo , Modelos Animales de Enfermedad , Hígado Graso/sangre , Hígado Graso/genética , Hígado Graso/patología , Regulación de la Expresión Génica , Lipogénesis/efectos de los fármacos , Lipogénesis/genética , Hígado/metabolismo , Hígado/patología , Transportador 1 de Anión Orgánico Específico del Hígado , Masculino , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Transportadores de Anión Orgánico Sodio-Independiente/genética , Transportadores de Anión Orgánico Sodio-Independiente/metabolismo , Índice de Severidad de la Enfermedad , Terfenadina/toxicidad , Triglicéridos/metabolismoRESUMEN
Hepatic fibrin deposition has been shown to inhibit hepatocellular injury in mice exposed to the bile duct toxicant α-naphthylisothiocyanate (ANIT). Degradation of fibrin clots by fibrinolysis controls the duration and extent of tissue fibrin deposition. Thus, we sought to determine the effect of treatment with the antifibrinolytic drug tranexamic acid (TA) and plasminogen activator inhibitor-1 (PAI-1) deficiency on ANIT-induced liver injury and fibrosis in mice. Plasmin-dependent lysis of fibrin clots was impaired in plasma from mice treated with TA (1200 mg/kg i.p., administered twice daily). Prophylactic TA administration reduced hepatic inflammation and hepatocellular necrosis in mice fed a diet containing 0.025% ANIT for 2 weeks. Hepatic type 1 collagen mRNA expression and deposition increased markedly in livers of mice fed ANIT diet for 4 weeks. To determine whether TA treatment could inhibit this progression of liver fibrosis, mice were fed ANIT diet for 4 weeks and treated with TA for the last 2 weeks. Interestingly, TA treatment largely prevented increased deposition of type 1 collagen in livers of mice fed ANIT diet for 4 weeks. In contrast, biliary hyperplasia/inflammation and liver fibrosis were significantly increased in PAI-1(-/-) mice fed ANIT diet for 4 weeks. Overall, the results indicate that fibrinolytic activity contributes to ANIT diet-induced liver injury and fibrosis in mice. In addition, these proof-of-principle studies suggest the possibility that therapeutic intervention with an antifibrinolytic drug could form a novel strategy to prevent or reduce liver injury and fibrosis in patients with liver disease.
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Antifibrinolíticos/uso terapéutico , Enfermedades de los Conductos Biliares/tratamiento farmacológico , Cirrosis Hepática/prevención & control , Hígado/efectos de los fármacos , Ácido Tranexámico/uso terapéutico , 1-Naftilisotiocianato/farmacología , Animales , Antifibrinolíticos/administración & dosificación , Enfermedades de los Conductos Biliares/inducido químicamente , Enfermedades de los Conductos Biliares/metabolismo , Enfermedades de los Conductos Biliares/patología , Colágeno Tipo I/biosíntesis , Modelos Animales de Enfermedad , Fibrina/metabolismo , Fibrinógeno/genética , Hígado/metabolismo , Hígado/patología , Cirrosis Hepática/inducido químicamente , Cirrosis Hepática/metabolismo , Cirrosis Hepática/patología , Ratones , Ratones Endogámicos C57BL , Ratones Noqueados , Inhibidor 1 de Activador Plasminogénico/deficiencia , Inhibidor 1 de Activador Plasminogénico/genética , Ácido Tranexámico/administración & dosificaciónRESUMEN
1,1,1-Trichloro-2,2-bis(2-chlorophenyl-4-chlorophenyl)ethane (o,p'-DDT) is an organochlorine pesticide and endocrine disruptor known to activate the estrogen receptor. Comprehensive ligand- and species-comparative dose- and time-dependent studies were conducted to systematically assess the uterine physiological, morphological and gene expression responses elicited by o,p'-DDT and ethynyl estradiol (EE) in immature ovariectomized C57BL/6 mice and Sprague-Dawley rats. Custom cDNA microarrays were used to identify conserved and divergent differential gene expression responses. A total of 1256 genes were differentially expressed by both ligands in both species, 559 of which exhibited similar temporal expression profiles suggesting that o,p'-DDT elicits estrogenic effects at high doses when compared to EE. However, 51 genes exhibited species-specific uterine expression elicited by o,p'-DDT. For example, carbonic anhydrase 2 exhibited species- and ligand-divergent expression as confirmed by quantitative real-time PCR. The identification of comparable temporal phenotypic responses linked to gene expression demonstrates that systematic comparative gene expression assessments are valuable for elucidating conserved and divergent estrogen signaling mechanisms in rodent uterotrophy.
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DDT/toxicidad , Expresión Génica , Plaguicidas/toxicidad , Útero/efectos de los fármacos , Animales , Disruptores Endocrinos/toxicidad , Estrógenos/toxicidad , Femenino , Perfilación de la Expresión Génica , Ratones , Ratones Endogámicos C57BL , Análisis de Secuencia por Matrices de Oligonucleótidos , ARN/genética , ARN/aislamiento & purificación , Ratas , Ratas Sprague-Dawley , Reacción en Cadena en Tiempo Real de la Polimerasa , Receptores de Estrógenos/genética , Receptores de Estrógenos/metabolismo , Especificidad de la Especie , Útero/metabolismo , Útero/patologíaRESUMEN
BACKGROUND: Allergic rhinitis frequently occurs as a comorbid condition in asthmatic people, suggesting that the upper and lower airways may be immunologically linked. Our research group has developed an experimental aeroallergen model of asthma in cats. We hypothesized that aeroallergen sensitization and challenge would induce morphologic changes in the nasal airways of cats that mimic those observed in the bronchial airways. METHODS: Five mixed breed cats were sensitized to Bermuda grass allergen and then serially challenged with aerosolized Bermuda grass allergen to induce an asthmatic phenotype. Four control cats were similarly treated with saline vehicle. Nasal tissues and lungs were processed for histopathological and morphometric analyses. RESULTS: Eosinophilic inflammation, epithelial hypertrophy and mucous cell metaplasia were observed along the pulmonary axial airway mucosa of allergen-sensitized (asthmatic) cats. Mild eosinophilic inflammation was observed in the nasal airways of asthmatic cats. This alteration was confined primarily to the anterior nasal cavity, resulting in an increase in tissue eosinophils at this site compared to controls (p < 0.05). A marked increase in tissue mast cells was observed throughout all regions of the nasal airways of asthmatic cats compared to control cats (p < 0.05). There was no difference in intraepithelial mucosubstances between the nasal airways of controls and asthmatic cats. There was no correlation between upper and lower airway eosinophils or mast cells. CONCLUSION: Cats with experimentally induced asthma exhibit morphologic changes in the nasal airways that are distinct from the alterations observed in the lungs. These results are similar to those observed in people with comorbid asthma and allergic rhinitis.
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Asma/inmunología , Hiperreactividad Bronquial/inmunología , Mucosa Nasal/inmunología , Mucosa Respiratoria/inmunología , Sistema Respiratorio/inmunología , Alérgenos/administración & dosificación , Alérgenos/inmunología , Animales , Asma/patología , Hiperreactividad Bronquial/patología , Líquido del Lavado Bronquioalveolar/citología , Gatos , Cynodon/inmunología , Eosinófilos/inmunología , Pulmón/inmunología , Pulmón/patología , Mastocitos/inmunología , Mucosa Nasal/patología , Mucosa Respiratoria/patología , Sistema Respiratorio/patología , Rinitis Alérgica , Rinitis Alérgica Perenne/inmunología , Rinitis Alérgica Perenne/patologíaRESUMEN
BACKGROUND: Patients with acetaminophen (APAP)-induced acute liver failure (ALF) display both hyper- and hypocoagulable changes not necessarily recapitulated by standard hepatotoxic doses of APAP used in mice (eg, 300 mg/kg). OBJECTIVES: We sought to examine coagulation activation in vivo and plasma coagulation potential ex vivo in experimental settings of APAP-induced hepatotoxicity and repair (300-450 mg/kg) and APAP-induced ALF (600 mg/kg) in mice. RESULTS: APAP-induced ALF was associated with increased plasma thrombin-antithrombin complexes, decreased plasma prothrombin, and a dramatic reduction in plasma fibrinogen compared with lower APAP doses. Hepatic fibrin(ogen) deposits increased independent of APAP dose, whereas plasma fibrin(ogen) degradation products markedly increased in mice with experimental ALF. Early pharmacologic anticoagulation (+2 hours after 600 mg/kg APAP) limited coagulation activation and reduced hepatic necrosis. The marked coagulation activation evident in mice with APAP-induced ALF was associated with a coagulopathy detectable ex vivo in plasma. Specifically, prolongation of the prothrombin time and inhibition of tissue factor-initiated clot formation were evident even after restoration of physiological fibrinogen concentrations. Plasma endogenous thrombin potential was similarly reduced at all APAP doses. Interestingly, in the presence of ample fibrinogen, â¼10 times more thrombin was required to clot plasma from mice with APAP-induced ALF compared with plasma from mice with simple hepatotoxicity. CONCLUSION: The results indicate that robust pathologic coagulation cascade activation in vivo and suppressed coagulation ex vivo are evident in mice with APAP-induced ALF. This unique experimental setting may fill an unmet need as a model to uncover mechanistic aspects of the complex coagulopathy of ALF.
Asunto(s)
Trastornos de la Coagulación Sanguínea , Enfermedad Hepática Inducida por Sustancias y Drogas , Fallo Hepático , Ratones , Animales , Acetaminofén/metabolismo , Trombina/metabolismo , Fallo Hepático/metabolismo , Fallo Hepático/patología , Hígado/metabolismo , Fibrina/metabolismo , Trastornos de la Coagulación Sanguínea/inducido químicamente , Trastornos de la Coagulación Sanguínea/metabolismo , Fibrinógeno/metabolismo , Enfermedad Hepática Inducida por Sustancias y Drogas/etiología , Enfermedad Hepática Inducida por Sustancias y Drogas/patología , Ratones Endogámicos C57BLRESUMEN
BACKGROUND: Blood coagulation protease activity is proposed to drive hepatic fibrosis through activation of protease-activated receptors (PARs). Whole-body PAR-1 deficiency reduces experimental hepatic fibrosis, and in vitro studies suggest a potential contribution by PAR-1 expressed by hepatic stellate cells. However, owing to a lack of specific tools, the cell-specific role of PAR-1 in experimental hepatic fibrosis has never been formally investigated. Using a novel mouse expressing a conditional PAR-1 allele, we tested the hypothesis that PAR-1 expressed by hepatic stellate cells contributes to hepatic fibrosis. METHODS: PAR-1flox/flox mice were crossed with mice expressing Cre recombinase controlled by the lecithin retinol acyltransferase (LRAT) promoter, which induces recombination in hepatic stellate cells. Male PAR-1flox/flox/LRATCre and PAR-1flox/flox mice were challenged twice weekly with carbon tetrachloride (CCl4, 1 mL/kg i.p.) for 6 weeks to induce liver fibrosis. RESULTS: PAR-1 mRNA levels were reduced (>95%) in hepatic stellate cells isolated from PAR-1flox/flox/LRATCre mice. Hepatic stellate cell activation was evident in CCl4-challenged PAR-1flox/flox mice, indicated by increased α-smooth muscle actin labeling and induction of several profibrogenic genes. CCl4-challenged PAR-1flox/flox mice displayed robust hepatic collagen deposition, indicated by picrosirius red staining and type I collagen immunolabeling. Notably, stellate cell activation and collagen deposition were significantly reduced (>30%) in PAR-1flox/flox/LRATCre mice. Importantly, the reduction in liver fibrosis was not a consequence of reduced acute CCl4 hepatotoxicity in PAR-1flox/flox/LRATCre mice. CONCLUSIONS: The results constitute the first direct experimental evidence that PAR-1 expressed by stellate cells directly promotes their profibrogenic phenotype and hepatic fibrosis in vivo.
RESUMEN
We have previously reported that Delta-9-tetrahydrocannabinol (Delta(9)-THC)-treated mice challenged with influenza virus A/PR/8/34 (PR8) developed increased viral hemagglutinin 1 (H1) mRNA levels and decreased monocyte and lymphocyte recruitment to the pulmonary airways when compared with mice challenged with PR8 alone. The objective of the present study was to examine the role of cannabinoid (CB(1)/CB(2)) receptors in mediating the effects of Delta(9)-THC on immune and epithelial cell responses to PR8. In the current study, Delta(9)-THC-treated CB(1)/CB(2) receptor null (CB(1)-/-/CB(2)-/-) and wild-type mice infected with PR8 had marked increases in viral H1 mRNA when compared with CB(1)-/-/CB(2)-/- and wild-type mice challenged with PR8 alone. However, the magnitude of the H1 mRNA levels was greatly reduced in CB(1)-/-/CB(2)-/- mice as compared with wild-type mice. In addition, Delta(9)-THC-treated CB(1)-/-/CB(2)-/- mice infected with PR8 had increased CD4+ T cells and IFN-gamma in bronchoalveolar lavage fluid with greater pulmonary inflammation when compared with Delta(9)-THC-treated wild-type mice infected with PR8. Delta(9)-THC treatment of CB(1)-/-/CB(2)-/- mice in the presence or absence of PR8 challenge also developed greater amounts of mucous cell metaplasia in the affected bronchiolar epithelium. Collectively, the immune and airway epithelial cell responses to PR8 challenge in Delta(9)-THC-treated CB(1)-/-/CB(2)-/- and wild-type mice indicated the involvement of CB(1)/CB(2) receptor-dependent and -independent mechanisms.
Asunto(s)
Dronabinol/farmacología , Inflamación/fisiopatología , Virus de la Influenza A , Infecciones por Orthomyxoviridae/fisiopatología , Receptor Cannabinoide CB1/genética , Receptor Cannabinoide CB2/genética , Linfocitos T/inmunología , Animales , Líquido del Lavado Bronquioalveolar , Modelos Animales de Enfermedad , Femenino , Citometría de Flujo , Inflamación/patología , Ratones , Ratones Endogámicos C57BL , Infecciones por Orthomyxoviridae/genética , ARN/genética , ARN/aislamiento & purificación , Receptor Cannabinoide CB1/deficiencia , Receptor Cannabinoide CB2/deficienciaRESUMEN
A 2 yr old, neutered male rottweiler was evaluated for a chronic cough that had acutely worsened. Computed tomographic examination revealed a diffuse alveolar pattern in the right, middle, and left cranial lung lobes. Aerated parenchymal tissue was not observed in the left cranial lung lobe, and both lobes were markedly decreased in volume. Lobectomy of the right middle and left cranial lung lobes was performed. Histopathologic examination of both lungs identified alveolar collapse associated with marked chronic bronchial and bronchiolar luminal concentric fibrosis leading to reduced airway lumen diameter and bronchiolar destruction. The clinical signs and airway pathology were consistent with constrictive bronchiolitis obliterans. The dog remained stable for over 2 yr with glucocorticoid therapy and intermittent antimicrobics. Although the polypoid form of bronchiolitis obliterans has been described in cattle and occasionally in dogs, constrictive bronchiolitis obliterans has not been reported previously in veterinary species.
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Bronquiolitis Obliterante/veterinaria , Enfermedades de los Perros/diagnóstico , Animales , Antibacterianos/uso terapéutico , Bronquiolitis Obliterante/diagnóstico , Bronquiolitis Obliterante/tratamiento farmacológico , Constricción Patológica , Enfermedades de los Perros/tratamiento farmacológico , Perros , Masculino , Prednisona/uso terapéuticoRESUMEN
A 7-month-old Miniature Poodle acquired from a pet store developed cough and subsequently respiratory distress compatible with Bordetella bronchiseptica infection. Partial but incomplete resolution of clinical signs and thoracic radiographic/computed tomographic imaging lesions were noted with use of susceptibility-guided antimicrobials. Additionally, a concern for an infectious nidus led to left cranial lung lobectomy at 9 months of age. Histopathology predominantly revealed polypoid and constrictive bronchiolitis obliterans (i.e., small airway disease). Intermittent antimicrobial administration over the next 5 years failed to blunt progressive clinical signs. At 8 years, necropsy confirmed severe airway-centered interstitial fibrosis. This pattern of fibrosis was strongly suggestive of underlying small airway disease as the trigger. In retrospect, post-infectious bronchiolitis obliterans (PIBO), a syndrome in young children caused by pulmonary infections but not yet recognized in pet dogs, likely initiated a pathway of fibrosis in this dog. In dogs with risk factors for community-acquired pathogens such as Bordetella bronchiseptica, PIBO is a differential diagnosis with development of severe, persistent respiratory signs incompletely responsive to appropriate antimicrobials. Untreated PIBO may lead to airway-centered interstitial fibrosis. Future study is required to determine if targeted therapy of PIBO could alter the course of end-stage pulmonary fibrosis.
RESUMEN
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) exhibits antiestrogenic properties, including the inhibition of estrogen-induced uterine growth and proliferation. The inhibition of estrogen-mediated gene expression through ER/AhR cross-talk has been proposed as a plausible mechanism; however, only a limited number of inhibited responses have been investigated that are unlikely to fully account for the antiuterotrophic effects of TCDD. Therefore, the effects of TCDD on ethynyl estradiol (EE)-mediated uterine gene expression were investigated using cDNA microarrays with complementary physiological and histological phenotypic anchoring. Mice were gavaged with vehicle, 3 daily doses of 10 mug/kg EE, a single dose of 30 mug/kg TCDD, or a combination of EE plus TCDD and sacrificed after 4, 12, 24, and 72 h. TCDD cotreatment inhibited EE-induced uterine wet weight by 37, 23, and 45% at 12, 24, and 72 h, respectively. TCDD cotreatment also reduced EE-mediated stromal edema, hypertrophy, and hyperplasia and induced marked luminal epithelial cell apoptosis. A 2 x 2 factorial microarray design was used to identify EE- and TCDD-specific differential gene expression responses as well as their interactive effects. Only 133 of the 2753 EE-mediated differentially expressed genes were significantly modulated by TCDD cotreatment, indicating a gene-specific inhibitory response. The EE-mediated induction of many genes, including trefoil factor 1 and keratin 14, were inhibited by greater than 90% by TCDD. Functional annotation of inhibited responses was associated with cell proliferation, water and ion transport, and maintenance of cellular structure and integrity. These inhibited responses correlate with the observed histological alterations and may contribute to the antiuterotrophic effects of TCDD.
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Estrógenos/fisiología , Expresión Génica/fisiología , Dibenzodioxinas Policloradas/farmacología , Útero/efectos de los fármacos , Animales , Femenino , Ratones , Análisis de Secuencia por Matrices de Oligonucleótidos , Útero/metabolismoRESUMEN
BACKGROUND: Dichlorodiphenyltrichloroethane (DDT) is a persistent estrogenic organochlorine pesticide that is a rodent hepatic tumor promoter, with inconclusive carcinogenicity in humans. We have previously reported that o, p'-DDT elicits primarily PXR/CAR-mediated activity, rather than ER-mediated hepatic responses, and suggested that CAR-mediated effects, as opposed to ER-mediated effects, may be more important in tumor promotion in the rat liver. To further characterize species-specific hepatic responses, gene expression analysis, with complementary histopathology and tissue level analyses were investigated in immature, ovariectomized C57BL/6 mice treated with 300 mg/kg o, p'-DDT, and compared to Sprague-Dawley rat data. RESULTS: Rats and mice exhibited negligible histopathology with rapid o, p'-DDT metabolism. Gene expression profiles were also similar, exhibiting PXR/CAR regulation with the characteristic induction of Cyp2b10 and Cyp3a11. However, PXR-specific target genes such as Apoa4 or Insig2 exhibited more pronounced induction compared to CAR-specific genes in the mouse. In addition, mouse Car mRNA levels decreased, possibly contributing to the preferential activation of mouse PXR. ER-regulated genes Cyp17a1 and Cyp7b1 were also induced, suggesting o, p'-DDT also elicits ER-mediated gene expression in the mouse, while ER-mediated effects were negligible in the rat, possibly due to the inhibitory effects of CAR on ER activities. In addition, o, p'-DDT induced Gadd45a, Gadd45b and Cdkn1, suggesting DNA damage may be an additional risk factor. Furthermore, elevated blood DHEA-S levels at 12 h after treatment in the mouse may also contribute to the endocrine-related effects of o, p'-DDT. CONCLUSION: Although DDT is known to cause rodent hepatic tumors, the marked species differences in PXR/CAR structure, expression patterns and ligand preference as well as significant species-specific differences in steroidogenesis, especially CYP17A1 expression and activity, confound the extrapolation of these results to humans. Nevertheless, the identification of potential modes of action as well as species-specific responses may assist in the selection and further development of more appropriate models for assessing the toxicity of DDT to humans and wildlife.
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Diclorodifenil Dicloroetileno/toxicidad , Insecticidas/toxicidad , Hígado/efectos de los fármacos , Receptores Citoplasmáticos y Nucleares/metabolismo , Receptores de Estrógenos/metabolismo , Receptores de Esteroides/metabolismo , Factores de Transcripción/metabolismo , Androstenodiona/sangre , Animales , Análisis por Conglomerados , Receptor de Androstano Constitutivo , Sulfato de Deshidroepiandrosterona/sangre , Diclorodifenil Dicloroetileno/metabolismo , Femenino , Perfilación de la Expresión Génica , Regulación de la Expresión Génica , Insecticidas/metabolismo , Hígado/metabolismo , Ratones , Ratones Endogámicos C57BL , Análisis de Secuencia por Matrices de Oligonucleótidos , Receptor X de Pregnano , Ratas , Ratas Sprague-Dawley , Receptores Citoplasmáticos y Nucleares/efectos de los fármacos , Receptores Citoplasmáticos y Nucleares/genética , Receptores de Estrógenos/efectos de los fármacos , Receptores de Estrógenos/genética , Receptores de Esteroides/efectos de los fármacos , Receptores de Esteroides/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Especificidad de la Especie , Esteroide 17-alfa-Hidroxilasa/efectos de los fármacos , Esteroide 17-alfa-Hidroxilasa/genética , Esteroide 17-alfa-Hidroxilasa/metabolismo , Factores de Transcripción/efectos de los fármacos , Factores de Transcripción/genéticaRESUMEN
Technical-grade dichlorodiphenyltrichloroethane (DDT) is an agricultural pesticide and malarial vector control agent that has been designated a potential human hepatocarcinogen. The o,p'-enantiomer exhibits estrogenic activity that has been associated with the carcinogenicity of DDT. The temporal and dose-dependent hepatic estrogenicity of o,p'-DDT was investigated using complementary DNA microarrays in immature ovariectomized Sprague-Dawley rats with complementary histopathology and tissue-level analysis. Animals were gavaged with 300 mg/kg o,p'-DDT either once or once daily for 3 consecutive days. Liver samples were examined 2, 4, 8, 12, 18, or 24 h after a single dose or following three daily doses. For dose-response studies, a single dose of 3, 10, 30, 100, or 300 mg/kg body weight o,p'-DTT was administered for 3 consecutive days. Genes associated with drug metabolism (Cyp2b2 and Cyp3a2), the nuclear receptors constitutive androstane receptor (CAR) and pregnane X receptor (PXR), cell proliferation (Ccnd1, Ccnb1, Ccnb2, and Stmn1), and oxidative stress (Gclm and Hmox1) were significantly induced. Cyp2b2 exhibited dose-dependent regulation and was significantly induced across all time points, while cell proliferation- and oxidative stress-related genes exhibited transient induction. The induction of Cyp2b2 and Cyp3a2 mRNA levels suggest PXR/CAR activation, consistent with expression of genes associated with oxidative stress. Few genes known to be estrogen receptor (ER) regulated were differentially expressed when compared to the hepatic gene expression profile elicited by ethynyl estradiol in immature ovariectomized C57BL/6 mice using the same study design and analysis methods. These data indicate that o,p'-DDT elicits PXR/CAR-, not ER-, mediated gene expression in the rat liver. Based on the species-specific differences in CAR regulation, the extrapolation of rodent DDT hepatocarcinogenicity to humans warrants further investigation.
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Carcinógenos Ambientales/toxicidad , DDT/toxicidad , Expresión Génica/efectos de los fármacos , Hígado/efectos de los fármacos , Receptores Citoplasmáticos y Nucleares/metabolismo , Receptores de Estrógenos/metabolismo , Receptores de Esteroides/metabolismo , Factores de Transcripción/metabolismo , Administración Oral , Animales , Proliferación Celular/efectos de los fármacos , Receptor de Androstano Constitutivo , Relación Dosis-Respuesta a Droga , Femenino , Perfilación de la Expresión Génica , Hígado/metabolismo , Hígado/patología , Ratones , Ratones Endogámicos C57BL , Análisis de Secuencia por Matrices de Oligonucleótidos , Ovariectomía , Receptor X de Pregnano , Ratas , Ratas Sprague-Dawley , Receptores Citoplasmáticos y Nucleares/genética , Receptores de Estrógenos/genética , Receptores de Esteroides/genética , Factores de Transcripción/genéticaRESUMEN
CASE DESCRIPTION: 5 horses were evaluated because of decreased appetite, weight loss, fever, cough, tachypnea, and respiratory distress. CLINICAL FINDINGS: Tachycardia, tachypnea, increased respiratory effort, lethargy, fever, poor body condition, and nasal discharge were detected in various combinations on initial physical examination. Evaluation of the lower portion of the respiratory tract via radiography and ultrasonography revealed a severe nodular interstitial pattern. Histologic examination of lung tissue revealed interstitial expansion of alveolar parenchyma with collagen, intraluminal accumulation of neutrophils and macrophages within the alveoli, and occasional intranuclear inclusion bodies within alveolar macrophages. Equine herpesvirus type 5 was detected in samples of lung tissue, bronchoalveolar lavage fluid, or both via polymerase chain reaction assay in all cases. A diagnosis of equine multinodular pulmonary fibrosis (EMPF) was established. TREATMENT AND OUTCOME: Horses were provided supportive treatment and were administered a variety of medications including corticosteroids and acyclovir. Two horses survived and returned to their previous level of activity. Three horses were euthanized because of either deterioration of clinical condition (n=2) or failure to improve within 4 weeks of initiation of treatment (1). CLINICAL RELEVANCE: EMPF should be considered as a differential diagnosis for adult horses with interstitial pneumonia and should be suspected on the basis of characteristic radiographic, ultrasonographic, and histopathologic findings. Equine herpesvirus type 5 is found in association with EMPF; although the exact pathogenic role this virus plays in EMPF is unknown, equine herpesvirus type 5 may be an etiologic agent or cofactor in the development of EMPF.
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Infecciones por Herpesviridae/veterinaria , Enfermedades de los Caballos/diagnóstico , Fibrosis Pulmonar/veterinaria , Varicellovirus/aislamiento & purificación , Aciclovir/uso terapéutico , Corticoesteroides/uso terapéutico , Animales , Antivirales/uso terapéutico , Diagnóstico Diferencial , Resultado Fatal , Femenino , Infecciones por Herpesviridae/complicaciones , Infecciones por Herpesviridae/diagnóstico , Infecciones por Herpesviridae/tratamiento farmacológico , Enfermedades de los Caballos/tratamiento farmacológico , Caballos , Masculino , Fibrosis Pulmonar/diagnóstico , Fibrosis Pulmonar/tratamiento farmacológico , Fibrosis Pulmonar/virología , Factores de Riesgo , Resultado del TratamientoRESUMEN
BACKGROUND: Uterine temporal and dose-dependent histopathologic, morphometric and gene expression responses to the selective estrogen receptor modulator tamoxifen (TAM) were comprehensively examined to further elucidate its estrogen receptor-mediated effects. These results were systematically compared to the effects elicited by the potent estrogen receptor ligand 17alpha-ethynylestradiol (EE) to identify pathways similarly and uniquely modified by each compound. RESULTS: Three daily doses of 100 microg/kg TAM elicited a dose-dependent increase in uterine wet weight (UWW) in immature, ovariectomized C57BL/6 mice at 72 hrs with concurrent increases in luminal epithelial cell height (LECH), luminal circumference and glandular epithelial tubule number. Significant UWW and LECH increases were detected at 24 hrs after a single dose of 100 microg/kg TAM. cDNA microarray analysis identified 2235 differentially expressed genes following a single dose of 100 microg/kg TAM at 2, 4, 8, 12, 18 and 24 hrs, and at 72 hrs after three daily doses (3 x 24 hrs). Functional annotation of differentially expressed genes was associated with cell growth and proliferation, cytoskeletal organization, extracellular matrix modification, nucleotide synthesis, DNA replication, protein synthesis and turnover, lipid metabolism, glycolysis and immunological responses as is expected from the uterotrophic response. Comparative analysis of TAM and EE treatments identified 1209 common, differentially expressed genes, the majority of which exhibited similar profiles despite a temporal delay in TAM elicited responses. However, several conserved and treatment specific responses were identified that are consistent with proliferation (Fos, Cdkn1a, Anapc1), and water imbibition (Slc30a3, Slc30a5) responses elicited by EE. CONCLUSION: Overall, TAM and EE share similar gene expression profiles. However, TAM responses exhibit lower efficacy, while responses unique to EE are consistent with the physiological differences elicited between compounds.
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Etinilestradiol/farmacología , Perfilación de la Expresión Génica , Tamoxifeno/farmacología , Transcripción Genética/efectos de los fármacos , Útero/efectos de los fármacos , Animales , Relación Dosis-Respuesta a Droga , Femenino , Ratones , Ratones Endogámicos C57BL , Análisis de Secuencia por Matrices de Oligonucleótidos , Tamaño de los Órganos/efectos de los fármacos , Ovariectomía , Útero/metabolismoRESUMEN
Equine herpesvirus 5 (EHV-5) infection is associated with pulmonary fibrosis in horses, but further studies on EHV-5 persistence in equine cells are needed to fully understand viral and host contributions to disease pathogenesis. Our aim was to develop a quantitative PCR (qPCR) assay to measure EHV-5 viral copy number in equine cell cultures, blood lymphocytes, and nasal swabs of horses. Furthermore, we used a recently developed equine primary respiratory cell culture system to study EHV-5 pathogenesis at the respiratory tract. PCR primers and a probe were designed to target gene E11 of the EHV-5 genome. Sensitivity and repeatability were established, and specificity was verified by testing multiple isolates of EHV-5, as well as DNA from other equine herpesviruses. Four-week old fully differentiated (mature), newly seeded (immature) primary equine respiratory epithelial cell (ERECs), and equine dermal cell cultures were inoculated with EHV-5 and the cells and supernatants collected daily for 14days. Blood lymphocytes and nasal swabs were collected from horses experimentally infected with equine herpesvirus 1 (EHV-1). The qPCR assay detected EHV-5 at stable concentrations throughout 14days in inoculated mature EREC and equine dermal cell cultures (peaking at 202 and 5861 viral genomes per 106 cellular ß actin, respectively). EHV-5 copies detected in the immature EREC cultures increased over 14days and reached levels greater than 10,000 viral genomes per 106 cellular ß actin. Moreover, EHV-5 was detected in the lymphocytes of 76% of horses and in the nasal swabs of 84% of horses experimentally infected with EHV-1 pre-inoculation with EHV-1. Post-inoculation with EHV-1, EHV-5 was detected in lymphocytes of 52% of horses while EHV-5 levels in nasal swabs were not significantly different from pre-inoculation levels. In conclusion, qPCR was a reliable technique to investigate viral load in in vivo and in vitro samples, and EHV-5 replication in equine epithelial cells may be influenced by cellular stages of differentiation.
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Gammaherpesvirinae/aislamiento & purificación , Gammaherpesvirinae/fisiología , Infecciones por Herpesviridae/veterinaria , Enfermedades de los Caballos/virología , Reacción en Cadena en Tiempo Real de la Polimerasa/métodos , Replicación Viral , Animales , Replicación del ADN , ADN Viral/genética , Células Epiteliales/virología , Gammaherpesvirinae/genética , Infecciones por Herpesviridae/virología , Herpesvirus Équido 1/aislamiento & purificación , Caballos , Linfocitos/virología , Nariz/virología , Sistema Respiratorio/virología , Carga ViralRESUMEN
Trichloroethylene (TCE) is a persistent environmental contaminant proposed to contribute to autoimmune disease. Experimental studies in lupus-prone MRL+/+ mice have suggested that TCE exposure can trigger autoimmune hepatitis. The vast majority of studies examining the connection between TCE and autoimmunity utilize this model, and the impact of TCE exposure in other established models of autoimmune liver disease is not known. We tested the hypothesis that TCE exposure exacerbates experimental hepatic autoimmunity in dominant negative transforming growth factor beta receptor type II (dnTGFBRII) mice, which develop serological and histological features resembling human primary biliary cholangitis. Female 8-week-old wild-type and dnTGFBRII mice were exposed to TCE (0.5 mg/ml) or vehicle (1% ethoxylated castor oil) in the drinking water for 12 or 22 weeks. Liver histopathology in 20- and 30-week-old wild-type mice was unremarkable irrespective of treatment. Mild portal inflammation was observed in vehicle-exposed 20-week-old dnTGFBRII mice and was not exacerbated by TCE exposure. Vehicle-exposed 30-week-old dnTGFBRII mice developed anti-mitochondrial antibodies, marked hepatic inflammation with necrosis, and hepatic accumulation of both B and T lymphocytes. To our surprise, TCE exposure dramatically reduced hepatic parenchymal inflammation and injury in 30-week-old dnTGFBRII mice, reflected by changes in hepatic proinflammatory gene expression, serum chemistry, and histopathology. Interestingly, TCE did not affect hepatic B cell accumulation or induction of the anti-inflammatory cytokine IL10. These data indicate that TCE exposure reduces autoimmune liver injury in female dnTGFBRII mice and suggests that the precise effect of environmental chemicals in autoimmunity depends on the experimental model.
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Enfermedad Hepática Inducida por Sustancias y Drogas/inmunología , Colangitis/inmunología , Modelos Animales de Enfermedad , Hepatitis Autoinmune/inmunología , Tricloroetileno/toxicidad , Animales , Autoanticuerpos/sangre , Enfermedad Hepática Inducida por Sustancias y Drogas/genética , Enfermedad Hepática Inducida por Sustancias y Drogas/patología , Colangitis/genética , Colangitis/patología , Femenino , Interacción Gen-Ambiente , Hepatitis Autoinmune/genética , Hepatitis Autoinmune/patología , Masculino , Ratones Transgénicos , Proteínas Serina-Treonina Quinasas/genética , Receptor Tipo II de Factor de Crecimiento Transformador beta , Receptores de Factores de Crecimiento Transformadores beta/genéticaRESUMEN
A 2-year-old, Quarter Horse filly was referred to Michigan State University, Veterinary Teaching Hospital with a 2-3 day history of depression and partial anorexia progressing to severe, watery diarrhea with severe neurologic abnormalities, including repetitive muscle fasciculations, muscle stiffening, and collapse. Laboratory findings included severe polycythemia, neutropenia, metabolic acidosis, and electrolyte and fluid loss, consistent with watery diarrhea and endotoxic shock. Increased creatine kinase and aspartate transaminase activities were consistent with recent transport and the muscle abnormalities. Severe hyperammonemia (1369.0 micromol/L; control value, 15.3 micromol/L) was found, without other substantial laboratory evidence of hepatic dysfunction. The horse was euthanized because of poor prognosis and rapid clinical deterioration. Necropsy findings were unremarkable with the exception of severe diffuse colitis. Culture of colonic contents recovered >1000 colony-forming units of Clostridium perfringens. Based on these findings, marked hyperammonemia in this filly was attributed to changes in colonic flora leading to increased bacterial production of ammonia that was readily absorbed through the inflamed bowel wall, exceeding the hepatic capacity for deamination. Intestinal bacteria as a source of hyperammonemia in the absence of hepatic disease has been linked rarely to positive culture results for clostridial organisms.
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Diarrea/veterinaria , Enfermedades de los Caballos/sangre , Enfermedades de los Caballos/fisiopatología , Hiperamonemia/veterinaria , Enfermedades del Sistema Nervioso/veterinaria , Animales , Diarrea/complicaciones , Femenino , Caballos , Hiperamonemia/sangre , Hiperamonemia/complicaciones , Enfermedades del Sistema Nervioso/complicaciones , Enfermedades del Sistema Nervioso/fisiopatologíaRESUMEN
Regional differences in large equine pulmonary artery reactivity exist. It is not known if this heterogeneity extends into small vessels. The hypothesis that there is regional heterogeneity in small pulmonary artery and vein reactivity to sympathomimetics (phenylephrine and isoproterenol) and a parasympathomimetic (methacholine) was tested using wire myography on small vessels from caudodorsal (CD) and cranioventral (CV) lung of 12 horses [9 mares, 3 geldings, 8.67 ± 0.81 (age ± SE) yr, of various breeds that had never raced]. To study relaxation, vessels were precontracted with U46619 (10(-6) M). Methacholine mechanism of action was investigated using L-nitroarginine methylester (L-NAME, 100 µM) and indomethacin (10 µM). Phenylephrine did not contract any vessels. Isoproterenol relaxed CD arteries more than CV arteries (maximum relaxation 28.18% and 48.67%; Log IC50 ± SE -7.975 ± 0.1327 and -8.033 ± 0.1635 for CD and CV, respectively, P < 0.0001), but not veins. Methacholine caused contraction of CD arteries (maximum contraction 245.4%, Log EC50 ± SE -6.475 ± 0.3341), and relaxation of CV arteries (maximum relaxation 40.14%, Log IC50 ± SE -6.791 ± 0.1954) and all veins (maximum relaxation 50.62%, Log IC50 ± SE -6.932 ± 0.1986) in a nonregion-dependent manner. L-NAME (n = 8, P < 0.0001) and indomethacin (n = 7, P < 0.0001) inhibited methacholine-induced relaxation of CV arteries, whereas indomethacin augmented CD artery contraction (n = 8, P < 0.0001). Our data demonstrate significant regional heterogeneity in small blood vessel reactivity when comparing the CD to the CV region of the equine lung.
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Pulmón/irrigación sanguínea , Arteria Pulmonar/fisiología , Venas/fisiología , Ácido 15-Hidroxi-11 alfa,9 alfa-(epoximetano)prosta-5,13-dienoico/farmacología , Animales , Endotelio Vascular/efectos de los fármacos , Endotelio Vascular/fisiología , Femenino , Caballos , Indometacina/farmacología , Isoproterenol/farmacología , Masculino , Cloruro de Metacolina/farmacología , Miografía/métodos , NG-Nitroarginina Metil Éster/farmacología , Fenilefrina/farmacología , Arteria Pulmonar/efectos de los fármacos , Vasoconstricción/efectos de los fármacos , Vasoconstrictores/farmacología , Vasodilatación/efectos de los fármacos , Vasodilatación/fisiología , Venas/efectos de los fármacosRESUMEN
2,3,7,8-Tetrachlorodibenzo-p-dioxin (TCDD) is a potent aryl hydrocarbon receptor agonist that elicits dose-dependent hepatic fat accumulation and inflammation that can progress to steatohepatitis. To investigate intestine-liver interactions that contribute to TCDD-elicited steatohepatitis, we examined the dose-dependent effects of TCDD (0.01, 0.03, 0.1, 0.3, 1, 3, 10, or 30 µg/kg) on jejunal epithelial gene expression in C57BL/6 mice orally gavaged every 4 days for 28 days. Agilent 4x44K whole-genome microarray analysis of the jejunal epithelium identified 439 differentially expressed genes (|fold change| ≥ 1.5, P1(t) ≥ 0.999) across 1 or more doses, many related to lipid metabolism and immune system processes. TCDD-elicited differentially expressed genes were associated with lipolysis, fatty acid/cholesterol absorption and transport, the Kennedy pathway, and retinol metabolism, consistent with increased hepatic fat accumulation. Moreover, several major histocompatibility complex (MHC) class II genes (H2-Aa, H2-Ab1, H2-DMb1, Cd74) were repressed, coincident with decreased macrophage and dendritic cell levels in the lamina propria, suggesting migration of antigen-presenting cells out of the intestine. In contrast, hepatic RNA-Seq analysis identified increased expression of MHC class II genes, as well as chemokines and chemokine receptors involved in macrophage recruitment (Ccr1, Ccr5, Ccl5, Cx3cr1), consistent with hepatic F4/80 labeling and macrophage infiltration into the liver. Collectively, these results suggest TCDD elicits changes that support hepatic lipid accumulation, macrophage migration, and the progression of hepatic steatosis to steatohepatitis.