RESUMEN
Chagas disease (CD) is a tropical zoonosis caused by the protozoan Trypanosoma cruzi. Severe autonomic dysfunction like reduced cardiac catecholamine-containing or acetylcholinesterase-positive innervation have been reported in CD. Renin-angiotensin system (RAS) seems to participate in the regulation of adrenal catecholamine secretion by adrenal medullary chromaffin cells, which might be dependent of nitric oxide (NO) pathways. To investigate the levels of RAS components in the adrenal gland during the acute infection with Y strain T. cruzi and in response to acute administration of an inhibitor of the enzyme NO synthase, L-NAME. Male Holtzman rats were inoculated intraperitoneally with Y strain T. cruzi and received L-NAME or tap water from one day before the infection until 13 or 17 days post-inoculation (dpi). The concentration of RAS molecules in the adrenal tissue was evaluated by ELISA immunoassay. Angiotensin converting enzyme 1 (ACE1) levels were significantly lower at 17 dpi when compared to 13 dpi. No significant differences were found compared with baseline, and no changes were detected in adrenal tissue levels of angiotensin converting enzyme 2 (ACE2), angiotensin II, or angiotensin-(1-7). Moreover, the treatment with L-NAME did not influence the levels of RAS components in adrenal tissue during the course of T. cruzi infection. We provided the first evidence that levels of RAS molecules change in the adrenal gland during acute phase of T. cruzi infection. Future studies are necessary to fully address the role of NO in RAS-associated adrenal gland function in CD.
Asunto(s)
Glándulas Suprarrenales/metabolismo , Enfermedad de Chagas/metabolismo , Óxido Nítrico/metabolismo , Sistema Renina-Angiotensina/fisiología , Trypanosoma cruzi/fisiología , Animales , Modelos Animales de Enfermedad , Masculino , NG-Nitroarginina Metil Éster/administración & dosificación , Óxido Nítrico Sintasa/antagonistas & inhibidores , Óxido Nítrico Sintasa/metabolismo , Peptidil-Dipeptidasa A/metabolismo , Ratas , Ratas Sprague-DawleyRESUMEN
At the site of infection, pro-inflammatory cytokines locally produced by macrophages infected with Trypanosoma cruzi can activate surrounding non-professional phagocytes such as fibroblasts, epithelial and endothelial cells, which can be further invaded by the parasite. The effect of secreted soluble factors on the invasion of these cells remains, however, to be established. We show here that two epithelial cell lines become significantly susceptible to the infection by the Y strain of T. cruzi after tumour necrosis factor (TNF) treatment. The increase in the invasion was correlated with the increasing concentration of recombinant TNF added to cultures of HEK293T or LLC-MK2 cells. Supernatants taken from PMA-differentiated human monocytes infected with T. cruzi also increased the permissiveness of epithelial cells to subsequent infection with the parasite, which was inhibited by a TNF monoclonal antibody. Furthermore, the permissiveness induced by TNF was inhibited by TPCK, and led to significant decrease in the number of intracellular parasites, providing evidence that activation of NF-κB induced by TNF favours the invasion of the epithelial cell lines by T. cruzi through yet an unidentified mechanism. Our data indicate that soluble factors released from macrophages early in the infection favours T. cruzi invasion of non-professional phagocytic cells.
Asunto(s)
Células Epiteliales/inmunología , Células Epiteliales/parasitología , FN-kappa B/metabolismo , Fagocitosis , Trypanosoma cruzi/patogenicidad , Factor de Necrosis Tumoral alfa/metabolismo , Animales , Línea Celular , Haplorrinos , HumanosRESUMEN
Chagas' disease (CD) is a zoonosis caused by the protozoan Trypanosoma cruzi. Besides being an important cause of cardiomyopathy, central nervous system (CNS) manifestations have also been reported in CD. Renin-Angiotensin System (RAS) plays a pathophysiological role in several brain disorders such as cerebrovascular and neurodegenerative diseases. A link between RAS and nitric oxide (NO) pathways has been described in CNS. For instance, Angiotensin-(1-7) increases NO expression in the brain, which may, in turn, help to control parasite load in response to T. cruzi infection. Herein, we investigated the levels of RAS components in the brain cortex in acute T. cruzi infection and the effect of L-NAME administration, an inhibitor of the enzyme NO synthase, in CNS infection and in RAS molecules. Male Holtzman rats were inoculated intraperitoneally with T. cruzi Y strain and received L-NAME or tap water from one day before the infection until 13 days post infection (dpi). Parasitemia was evaluated on alternate days from day 3 post-infection until day 13 in both T. cruzi infected groups. Histopathological analysis of the brain cortex was also performed. Brain cortex was collected from non-infected (controls) and infected rats at 13 dpi for RAS components assessment. Infected rats receiving L-NAME presented higher parasitemia, brain parasitism and inflammation compared with non-treated infected animals. The administration of L-NAME significantly decreased the levels of Angiotensin I Converting Enzyme 2 (ACE2). In conclusion, we provided preliminary evidence of the interaction between RAS and NO during the acute phase of T. cruzi infection.
Asunto(s)
Encéfalo/metabolismo , Encéfalo/parasitología , Enfermedad de Chagas/metabolismo , Enfermedad de Chagas/parasitología , Óxido Nítrico/metabolismo , Sistema Renina-Angiotensina/fisiología , Trypanosoma cruzi/fisiología , Animales , Enfermedad de Chagas/fisiopatología , Modelos Animales de Enfermedad , Masculino , Ratas , Ratas Sprague-Dawley , Trypanosoma cruzi/aislamiento & purificaciónRESUMEN
Disturbances of endothelin production or clearance contribute to the pathophysiology of several cardiovascular diseases including Chagas disease cardiomyopathy caused by the protozoan Trypanosoma cruzi. In rats, endothelins contribute to control the acute phase, probably by stimulating nitric oxide production. We point out the necessity for new studies to better evaluate high levels of endothelin in the course of other infectious diseases, for which only its detrimental effects have been emphasized.
Asunto(s)
Enfermedad de Chagas/metabolismo , Enfermedad de Chagas/parasitología , Endotelinas/metabolismo , Trypanosoma cruzi/fisiología , Enfermedad Aguda , Animales , Enfermedad de Chagas/patología , HumanosRESUMEN
Endothelin has been implicated in the pathogenesis of experimental and human Chagas' disease (American trypanosomiasis). In the present study, we tested the effect of bosentan, an antagonist of both ET(A) and ET(B) endothelin receptors, on parasitemia, histopathology (heart and diaphragm), heart levels of tumor necrosis factor (TNF)-alpha, interleukin (IL)-10, interferon (IFN)-gamma, CCL2, CCL3 and CCL5, and the serum levels of nitrate/nitrite (NOx). Bosentan treatment was accompanied by a significant increase in parasitemia and tissue parasitism or inflammation. In vehicle-treated rats, Trypanosoma cruzi infection increased the cardiac levels of TNF-alpha, IFN-gamma and IL-10, at day 9 post inoculation, and the TNF-alpha remained elevated until day 13. The infection also caused a significant increase in the cardiac levels of the chemokines CCL2 (9, 13 and 18 days) and CCL3 (13 and 18 days). Bosentan-treatment had no significant effect on the infection-associated increase in IFN-gamma and chemokine concentrations. There was a lower increase in IL-10 at day 9 and this was mirrored by a greater increase of TNF-alpha at day 13, in comparison with vehicle-treated rats. These latter findings correlated well with the enhanced inflammatory process in hearts of bosentan-treated infected rats. Bosentan treatment reduced the infection-associated increase in NOx serum concentration. Altogether, our data suggest that ET action on ET(A) and ET(B) receptors may play a role in the initial control of T. cruzi infection in rats probably by interfering in NO production.
Asunto(s)
Enfermedad de Chagas/patología , Enfermedad de Chagas/fisiopatología , Antagonistas de los Receptores de Endotelina , Endotelinas/fisiología , Trypanosoma cruzi/fisiología , Estructuras Animales/parasitología , Animales , Bosentán , Enfermedad de Chagas/parasitología , Quimiocinas/análisis , Citocinas/análisis , Diafragma/patología , Modelos Animales de Enfermedad , Masculino , Miocardio/química , Miocardio/patología , Nitratos/sangre , Nitritos/sangre , Parasitemia , Ratas , Sulfonamidas/farmacología , Trypanosoma cruzi/aislamiento & purificaciónRESUMEN
Micronutrient malnutrition is usually highly prevalent in areas endemic for Chagas disease. Nevertheless, the contribution of micronutrient deficiency to the immunopathology of this infection is often overlooked. In the present work, we assessed the effects of vitamin E deficiency on acute Trypanosoma cruzi (Y strain) infection of Holtzman rats. At 20 days post infection, vitamin E deficiency induced changes in leukocyte levels and exacerbated the myocarditis and sympathetic denervation of ventricular hearts. Vitamin E-deficient infected rats displayed significant leukopenia, evidenced by the decline in the numbers of CD45RA(+)CD3(-) B-cells and CD3(+)CD4(+) T-lymphocytes in the peripheral blood compared with infected control rats. In contrast, vitamin E deficiency induced monocytosis as well as an increased differentiation rate of monocytes to macrophages, as revealed by immunohistochemical analysis.
Asunto(s)
Enfermedad de Chagas/etiología , Deficiencia de Vitamina E/complicaciones , Animales , Enfermedades del Sistema Nervioso Autónomo/parasitología , Enfermedad de Chagas/inmunología , Enfermedad de Chagas/parasitología , Citometría de Flujo , Corazón/inervación , Inmunohistoquímica , Leucocitosis/parasitología , Macrófagos/parasitología , Masculino , Miocarditis/parasitología , Ratas , Ratas Sprague-Dawley , Linfocitos T/parasitología , Trypanosoma cruziRESUMEN
Chagas' disease, caused by Trypanosoma cruzi, has an acute phase characterized by blood-circulating trypomastigotes and amastigote proliferation in several cell types, especially muscle cells. In the chronic phase, around 70% of infected people are asymptomatic (latent form). The remainder develop chagasic cardiomyopathy and/or digestive syndromes. There is evidence for aggravation of the chronic cardiac pathology by endothelin-mediated vasoconstriction. Holtzman rats have proven to be a good model for Chagas' disease acute phase and latent chronic phase. Now, we investigate the effects of prolonged treatment with an endothelin ET(A) receptor antagonist, BSF 461314, during the acute phase on parasitemia, coronary flow, tissue parasitism and the inflammatory process. Using isolated heart in Langendorff's preparation, endothelial dysfunction was observed only in non-treated infected animals. Histoquantitative analyses carried out in heart and diaphragm showed higher tissue parasitism and/or inflammatory process in BSF 461314-treated animals. Our data indicate that endothelin ET(A) receptors contribute to the initial mechanisms of parasite control. Impairment of the endothelium-dependent vasodilatation favors hazardous effects. However, blocking endothelin ET(A) receptors can prevent the latter.
Asunto(s)
Enfermedad de Chagas/prevención & control , Receptor de Endotelina A/metabolismo , Trypanosoma cruzi , Enfermedad Aguda , Animales , Velocidad del Flujo Sanguíneo , Enfermedad de Chagas/tratamiento farmacológico , Enfermedad de Chagas/parasitología , Modelos Animales de Enfermedad , Antagonistas de los Receptores de la Endotelina A , Corazón/parasitología , Corazón/fisiopatología , Humanos , Inflamación , Masculino , Parasitemia/tratamiento farmacológico , Parasitemia/parasitología , Parasitemia/prevención & control , Fenilpropionatos/química , Fenilpropionatos/uso terapéutico , Pirimidinas/química , Pirimidinas/uso terapéutico , Ratas , Ratas Sprague-DawleyRESUMEN
We aim at investigating the role of blood born macrophages on the brain reaction to Trypanosoma cruzi infection in suckling rats. This infection provoked the appearance of numerous ED1(+) cells in the neural parenchyma and increased the amount of meningeal and perivascular ED2(+) macrophages. CD8(+) and NKR(+) cells also occurred. Parenchymal blood vessels showed strong ICAM-1 and decreased occludin immunoreactivities. Selective depletion of peripheral macrophages by clodronate liposomes decreased tissue parasitism, nodular lesions, ICAM-1 upregulation and leukocyte infiltration. Occludin immunoreactivity remained as in uninfected animals. Our results indicate a role for blood-born macrophages in both parasite invasion and brain reaction. Microglia activation cannot be discarded.
Asunto(s)
Infecciones Parasitarias del Sistema Nervioso Central/patología , Enfermedad de Chagas/tratamiento farmacológico , Ácido Clodrónico/uso terapéutico , Macrófagos/fisiología , Trypanosoma cruzi , Analgésicos no Narcóticos/uso terapéutico , Animales , Animales Lactantes/microbiología , Recuento de Células , Sistema Nervioso Central/irrigación sanguínea , Sistema Nervioso Central/citología , Sistema Nervioso Central/inmunología , Sistema Nervioso Central/metabolismo , Enfermedad de Chagas/metabolismo , Ectodisplasinas , Ensayo de Inmunoadsorción Enzimática/métodos , Inmunización/métodos , Inmunohistoquímica/métodos , Molécula 1 de Adhesión Intercelular/metabolismo , Interferón gamma/sangre , Leucocitos/clasificación , Leucocitos/metabolismo , Liposomas/farmacología , Macrófagos/efectos de los fármacos , Masculino , Proteínas de la Membrana/metabolismo , Ratones , Mortalidad , Ocludina , Ratas , Ratas Sprague-Dawley , Factores de Tiempo , Factor de Necrosis Tumoral alfa/metabolismoRESUMEN
The neurological involvement in acute liver failure (ALF) is characterized by arousal impairment with progression to coma. There is a growing body of evidence that neuroinflammatory mechanisms play a role in this process, including production of inflammatory cytokines and microglial activation. However, it is still uncertain whether brain-derived cytokines and glial cells are crucial to the pathophysiology of ALF at the early stage, before coma development. Here, we investigated the influence of cytokines and microglia in ALF-induced encephalopathy in mice as soon as neurological symptoms were identifiable. Behavior was assessed at 12, 24, 36 and 48 h post-injection of thioacetamide, a hepatotoxic drug, through locomotor activity by an open field test. Brain concentration of cytokines (TNF-α and IL-1ß) and chemokines (CXCL1, CCL2, CCL3 and CCL5) were assessed by ELISA. Microglial activation in brain sections was investigated through immunohistochemistry, and cellular ultrastructural changes were observed by transmission electron microscopy. We found that ALF-induced animals presented a significant decrease in locomotor activity at 24 h, which was accompanied by an increase in IL-1ß, CXCL1, CCL2, CCL3 and CCL5 in the brain. TNF-α level was significantly increased only at 36 h. Despite marked morphological changes in astrocytes and brain endothelial cells, no microglial activation was observed. These findings suggest an involvement of brain-derived chemokines and IL-1ß in early pathophysiology of ALF by a mechanism independent of microglial activation.
Asunto(s)
Encéfalo/metabolismo , Quimiocinas/metabolismo , Citocinas/metabolismo , Fallo Hepático Agudo/metabolismo , Microglía/metabolismo , Animales , Encéfalo/ultraestructura , Recuento de Células , Quimiocinas/sangre , Citocinas/sangre , Femenino , Rodamiento de Leucocito , Hígado/patología , Fallo Hepático Agudo/inducido químicamente , Fallo Hepático Agudo/patología , Ratones , Ratones Endogámicos C57BL , Microglía/citología , Actividad Motora/efectos de los fármacos , Tioacetamida/toxicidad , Regulación hacia ArribaRESUMEN
Endothelin has been implicated in the pathogenesis of experimental and human Chagas disease. In the present study, we investigated whether the treatment with bosentan, an antagonist of both ET(A)/ET(B) endothelin receptors, modified parasite load and inflammation in the central nervous system (CNS) of Trypanosomacruzi-infected rats. The cerebellum was the most affected region in the CNS with marked parasitism and inflammation. Treatment with bosentan enhanced parasitemia and CNS parasitism, but control of infection was eventually attained. There was also an increase in the levels of the cytokines TNF-alpha, IL-10, IFN-gamma, CCL2/MCP-1, CCL3/MIP-1alpha and CCL5/RANTES in the brain of infected animals at days 9, 13 and 18 after infection. Overall, bosentan has some effects on the expression of certain cytokines and this may be related to the initial enhanced parasite load. Altogether, our data suggest that endothelin action via ET(A) and ET(B) receptors may play a role in the initial resistance of the CNS to T. cruzi infection in rats.
Asunto(s)
Enfermedad de Chagas/complicaciones , Encefalitis/tratamiento farmacológico , Encefalitis/parasitología , Antagonistas de los Receptores de Endotelina , Sulfonamidas/farmacología , Trypanosoma cruzi/inmunología , Animales , Antihipertensivos/farmacología , Antihipertensivos/uso terapéutico , Antiparasitarios/farmacología , Antiparasitarios/uso terapéutico , Bosentán , Encéfalo/efectos de los fármacos , Encéfalo/inmunología , Encéfalo/parasitología , Citocinas/efectos de los fármacos , Citocinas/metabolismo , Modelos Animales de Enfermedad , Encefalitis/fisiopatología , Endotelinas/antagonistas & inhibidores , Endotelinas/metabolismo , Inmunidad Innata/efectos de los fármacos , Inmunidad Innata/inmunología , Masculino , Ratas , Ratas Sprague-Dawley , Receptores de Endotelina/metabolismo , Sulfonamidas/uso terapéutico , Resultado del Tratamiento , Regulación hacia Arriba/efectos de los fármacos , Regulación hacia Arriba/fisiologíaRESUMEN
Developmental studies indicate a role for GDNF in survival of motor, autonomic, and sensory neurons. However, no study attempted to demonstrate its participation in autonomic nerve regeneration. In this work, chemical sympathectomy by 6-hydroxydopamine provided the model for assessing heart GDNF expression during denervation and axonal regrowth. A glyoxylic acid-based histochemical technique evaluated the noradrenergic innervation. ELISA determined GDNF levels after concentrating heart homogenates. Light and ultrastructural in situ hybridization and immunocytochemistry were used for identifying cells expressing GDNF mRNA and protein. In control rats, the GDNF cardiac levels were significantly higher in 37-day-old animals in comparison with those aging 60 days. In sympathectomized rats, GDNF cardiac levels were significantly higher 7 days after sympathectomy and dropped to control levels at day 30. GDNF mRNA was expressed in atrial and ventricular myocytes from normal and sympathectomized rats. GDNF immunoreactivity occurred on atrial granules and quantitative analysis in electron micrographs confirmed ELISA-obtained data. In ventricular myocytes gold particles occurred sparsely. These findings constitute the first evidence for GDNF synthesis by cardiomyocytes and postulate a role for this factor soon after cardiac sympathetic denervation, probably in nerve regeneration. In atrial myocytes, GDNF is probably secreted by regulated pathway.
Asunto(s)
Corazón/inervación , Miocardio/metabolismo , Factores de Crecimiento Nervioso/metabolismo , Fármacos Neuroprotectores/metabolismo , Simpatectomía Química , Animales , Modelos Animales de Enfermedad , Ensayo de Inmunoadsorción Enzimática , Femenino , Factor Neurotrófico Derivado de la Línea Celular Glial , Corazón/efectos de los fármacos , Atrios Cardíacos/inervación , Atrios Cardíacos/ultraestructura , Ventrículos Cardíacos/inervación , Ventrículos Cardíacos/ultraestructura , Hibridación in Situ , Microscopía Electrónica , Miocardio/ultraestructura , Factores de Crecimiento Nervioso/genética , Regeneración Nerviosa , Sondas de Oligonucleótidos/química , Oxidopamina , ARN Mensajero/metabolismo , Ratas , Ratas Sprague-DawleyRESUMEN
Chagas' disease is caused by the intracellular protozoan Trypanosoma cruzi. Here we have investigated the role of endothelin-1 in T. cruzi acute infection in rats, using the orally active ET(A) receptor antagonist BSF-461314. Treatment with BSF-461314 markedly increased parasitaemia, but animals managed to control the infection by day 15. Histopathological analysis of heart tissue at the end of the acute phase showed greater numbers of parasite nests in BSF-461314-treated animals. The perfusion of isolated rat hearts from infected animals with bradykinin failed to induce an increase, and actually reduced, coronary blood flow. Pretreatment with BSF-461314 prevented changes in coronary flow induced by T. cruzi infection. Together these results demonstrate that endothelin-1, through ET(A) receptor activation, contributes to the protective immune response against acute T. cruzi infection. Moreover, these data suggest that endothelin-1 is a mediator of impaired endothelium-dependent vasomotion in the coronary microcirculation associated with acute T. cruzi infection.
Asunto(s)
Cardiomiopatía Chagásica/metabolismo , Antagonistas de los Receptores de Endotelina , Endotelina-1/fisiología , Parasitemia/metabolismo , Enfermedad Aguda , Animales , Bradiquinina , Cardiomiopatía Chagásica/inmunología , Cardiomiopatía Chagásica/parasitología , Corazón/parasitología , Masculino , Modelos Animales , Parasitemia/inmunología , Perfusión , Ratas , Ratas Sprague-Dawley , Receptor de Endotelina A , VasodilatadoresRESUMEN
The ultrastructure of endogenous stages of Eimeria ninakohlyakimovae was observed in epithelial cells of cecum and colon crypts from a goat experimentally infected with 2.0 x 10 5 occysts/kg. The secondary meronts developed above the nucleous first divides and merozoites then form on the surface of multinucleated meronts. Free merozoites in the parasitophorous vacuole present a conoid, double membrane, one pair of rhoptries, micronemes, micropore, anterior and posterior polar ring, a nucleus with a nuclelous and peripheral chromatin. The microgamonts are located below the nucleus of the host cell and contain several nuclei at the periphery of the parasite. The microgametes consist of a body, a nucleus, three flagella and mitochondria. The macrogamonts develop below the nucleus of the host cell and have a large nucleus with a prominent nucleus. The macrogametes contain a nucleus, wall-forming bodies of type I and II. The young oocysts present a wall containing two layers and a sporont.
Asunto(s)
Animales , Eimeria/ultraestructura , Cabras/parasitologíaRESUMEN
Monoclonal antibodies (MABs) were produced against an ethylenediaminetetraacetate (EDTA) extract of Leptospira interrogans serovar icterohaemorrhagiae being characterized by gel precipitation as IgM and IgG (IgG1 and IgG2b). The EDTA extract was detected as several bands by silver staining in SDS-PAGE. In the Western blot the bands around 20 KDa reacted with a monoclonal antibody, 47B4D6, and was oxidized by periodate and was not digested by pronase, suggesting that the determinant is of carbohydrate nature. Immunocytochemistry, using colloidal gold labeling, showed that an EDTA extract determinant recognized by monoclonal antibody 47B4D6, is localized under the outer envelope of serovar icterohaemorrhagiae. The MAB raised against the EDTA extract was not able to protect hamsters from lethal challenge with virulent homologous leptospires.