endothelin-1 and Chagas-Cardiomyopathy

The cardiovascular manifestations of Chagas disease are well known. However, the contribution of the vasculature and specifically the microvasculature has received little attention. This chapter reviews the evidence supporting the notion that alterations in the microvasculature especially in the heart contribute to the pathogenesis of chagasic cardiomyopathy. These data may also be important in understanding the contributions of the microvasculature in the aetiologies of other cardiomyopathies. The role of endothelin-1 and of thromboxane A(2) vascular spasm and platelet aggregation is also discussed. Further, these observations may provide target(s) for intervention.

Topics: Animals; Blood Vessels; Chagas Cardiomyopathy; Dogs; Endothelin-1; Humans; Mice; Platelet Aggregation; Thromboxane A2

Infection with Trypanosoma cruzi causes a generalised vasculitis of several vascular beds. This vasculopathy is manifested by vasospasm, reduced blood flow, focal ischaemia, platelet thrombi, increased platelet aggregation and elevated plasma levels of thromboxane A(2) and endothelin-1. In the myocardium of infected mice, myonecrosis and a vasculitis of the aorta, coronary artery, smaller myocardial vessels and the endocardial endothelium are observed. Immunohistochemistry studies employing anti-endothelin-1 antibody revealed increased expression of endothelin-1, most intense in the endocardial and vascular endothelium. Elevated levels of mRNA for prepro endothelin-1, endothelin converting enzyme and endothelin-1 were observed in the infected myocardium. When T. cruzi-infected mice were treated with phosphoramidon, an inhibitor of endothelin converting enzyme, there was a decrease in heart size and severity of pathology. Mitogen-activated protein kinases and the transcription factor activator-protein-1 regulate the expression of endothelin-1. Therefore, we examined the activation of mitogen-activated protein kinases in the myocardium by T. cruzi. Western blot demonstrated an extracellular signal regulated kinase. In addition, the activator-protein-1 DNA binding activity, as determined by electrophoretic mobility shift assay, was increased. Increased expression of cyclins A and cyclin D1 was observed in the myocardium, and immunohistochemistry studies revealed that interstitial cells and vascular and endocardial endothelial cells stained intensely with antibodies to these cyclins. These data demonstrate that T. cruzi infection of the myocardium activates extracellular signal regulated kinase, activator-protein-1, endothelin-1, and cyclins. The activation of these pathways is likely to contribute to the pathogenesis of chagasic heart disease. These experimental observations suggest that the vasculature plays a role in the pathogenesis of chagasic cardiomyopathy. Additionally, the identification of these pathways provides possible targets for therapeutic interventions to ameliorate or prevent the development of cardiomyopathy during T. cruzi infection.

Topics: Animals; Chagas Cardiomyopathy; Chagas Disease; Endothelin-1; Gene Expression Regulation; Heart; Humans; Immunohistochemistry; Mice

Chronic inflammation, as a consequence of the persistent infection with Trypanosoma cruzi, leads to continuous activation of the immune system in patients with chronic Chagas disease. We have previously shown that increased sera levels of soluble P-selectin are associated with the severity of the cardiomyopathy distinctive of chronic Chagas disease. In this study, we explored the expression of biomarkers of platelet and endothelial activation, tissue remodeling, and mediators of the coagulation cascade in patients at different clinical stages of chronic Chagas heart disease. The frequencies of activated platelets, measured by the expression of CD41a and CD62P were decreased in patients with chronic Chagas disease compared with those in uninfected subjects, with an inverse association with disease severity. Platelet activation in response to adenosine diphosphate was also decreased in T. cruzi-infected subjects. A major proportion of T. cruzi infected subjects showed increased serum levels of fibrinogen. Patients with severe cardiac dysfunction showed increased levels of endothelin-1 and normal values of procollagen I. In conclusion, chronic infection with T. cruzi induced hemostatic alterations, even in those patients who do not yet present cardiac symptoms.

Topics: Adolescent; Adult; Aged; Aged, 80 and over; Blood Platelets; Chagas Cardiomyopathy; Chagas Disease; Chronic Disease; Endothelin-1; Female; Fibrinogen; Humans; Inflammation; Male; Middle Aged; P-Selectin; Procollagen; Trypanosoma cruzi; Young Adult

The anti-inflammatory and cardioprotective properties of curcumin (Cur), a natural polyphenolic flavonoid isolated from the rhizomes of Curcuma longa, are increasingly considered to have beneficial effects on the progression of Chagas heart disease, caused by the protozoan parasite Trypanosoma cruzi.. To evaluate the effects of oral therapy with Cur on T. cruzi-mediated cardiovasculopathy in acutely infected mice and analyse the in vitro response of parasite-infected human microvascular endothelial cells treated with this phytochemical.. Inflammation of heart vessels from Cur-treated and untreated infected mice were analysed by histology, with benznidazole (Bz) as the reference compound. Parasitaemia was monitored by the direct method. Capillary permeability was visualised by Evans-blue assay. Myocardial ET-1, IL-6, and TNF-α mRNA expressions were measured by quantitative reverse transcription polymerase chain reaction (qRT-PCR). Microvascular endothelial HMEC-1 cells were infected in vitro with or without addition of Cur or Bz. Induction of the Ca2+/NFAT pathway was assessed by fluorometry, immunoblotting, and reporter assay.. Oral Cur therapy of recently infected mice reduced inflammatory cell infiltration of myocardial arteries without lowering parasite levels. Compared to that of the phosphate-buffered saline-receiving group, hearts from Cur-treated mice showed significantly decreased vessel inflammation scores (p < 0.001), vascular permeabilities (p < 0.001), and levels of IL-6/TNF-α (p < 0.01) and ET-1 (p < 0.05) mRNA. Moreover, Cur significantly (p < 0.05 for transcript; p < 0.01 for peptide) downregulated ET-1 secretion from infected HMEC-1 cells. Remarkably, Cur addition significantly (p < 0.05 at 27.0 μM) interfered with T. cruzi-dependent activation of the Ca2+/NFATc1 signalling pathway that promotes generation of inflammatory agents in HMEC-1 cells.. Oral treatment with Cur dampens cardiovasculopathy in acute Chagas mice. Cur impairs the Ca2+/NFATc1-regulated release of ET-1 from T. cruzi-infected vascular endothelium. These findings identify new perspectives for exploring the potential of Cur-based interventions to ameliorate Chagas heart disease.

Topics: Acute Disease; Animals; Anti-Inflammatory Agents, Non-Steroidal; Blotting, Western; Capillary Permeability; Cells, Cultured; Chagas Cardiomyopathy; Curcumin; Disease Progression; Endothelial Cells; Endothelin-1; Endothelium, Vascular; Enzyme-Linked Immunosorbent Assay; Fluorescent Dyes; Interleukin-6; Male; Mice, Inbred C57BL; NFATC Transcription Factors; Reproducibility of Results; Reverse Transcriptase Polymerase Chain Reaction; Time Factors; Trypanosoma cruzi; Tumor Necrosis Factor-alpha

Trypanosoma cruzi (Tc), the etiological agent of Chagas disease, triggers multiple responses in the myocardium, a central organ of infection and pathology in the host. Parasite-driven induction of diverse regulators of cardiovascular function, including the vasoconstrictor endothelin-1 (ET-1), the inducible form of nitric oxide synthase (iNOS) and the B-type natriuretic peptide (BNP), has been linked to the development of severe chagasic cardiomyopathy. Our current goal was to analyze the participation of the zinc finger transcription factor GATA4, critically implicated in pathological cardiac hypertrophic response, in the generation of key mediators involved in the pathogenesis of Tc-elicited heart dysfunction. In this study, we found that the combined effects of Tc and ET-1 on atrial myocytes promoted the protein expression, phosphorylation and DNA-binding activity of GATA4, leading to augmented protein levels of iNOS and increased nitric oxide release. Moreover, Tc- and ET-1-co-activation of cardiomyocytes resulted in enhanced GATA4-dependent secretion of BNP. Accordingly, mice with chronic chagasic cardiomyopathy showed increased expression of GATA4, iNOS and BNP at inflammatory lesions in cardiac muscle. Our findings support a role for the GATA4 signaling pathway in the myocardial production of pathogenic mediators associated with Chagas heart disease, and may help define novel therapeutic targets.

Topics: Animals; Cells, Cultured; Chagas Cardiomyopathy; Disease Models, Animal; Endothelin-1; GATA4 Transcription Factor; Mice, Inbred BALB C; Myocardium; Natriuretic Peptide, Brain; Nitric Oxide; Nitric Oxide Synthase Type II; Signal Transduction; Trypanosoma cruzi

Chagas heart disease is developed as a result of the infection with Trypanosoma cruzi. Protein malnutrition contributes to secondary immunodeficiency. The aim of this study was to investigate the role of a low protein diet on the production of endothelin-1 and CX3CL1 in blood and cardiac tissue samples in an experimental model with T. cruzi infection.. Fisher rats were submitted to low protein (6%) and normal protein (15%) diets and then infected with the Y strain of T. cruzi. At days 15 and 120, parasites and immune cells were evaluated.. The low protein diet reduced body weight and circulating serum proteins, but promoted elevation of CX3CL1 and endothelin-1 levels in infected animals, which were unable to control blood parasitemia replication. In heart tissue, the low protein diet reduced cardiac CX3CL1, endothelin-1 and leucocyte infiltration in the acute phase, in particular CD68 and CD163 macrophage phenotypes.. Together, these results highlight the participation of endothelin-1 and CX3CL1 in the inflammatory process of Chagas diesease, both being mediators partially controlled by the host nutritional status.

Topics: Animals; Chagas Cardiomyopathy; Chemokine CX3CL1; Diet, Protein-Restricted; Disease Models, Animal; Endothelin-1; Male; Protein Deficiency; Rats; Rats, Inbred F344; Trypanosoma cruzi

Chagas' disease, caused by the protozoan Trypanosoma cruzi, is a major cause of cardiovascular disability in countries where it is endemic. Damage to the heart microvasculature has been proposed to be an important factor in the pathogenesis of heart dysfunction. Endothelin-1 (ET-1) is a potent vasoconstrictor and exerts its effects via specific ET A and ET B receptors. A few studies have suggested a role for ET-1 and its receptors in the pathogenesis of Chagas' disease. We investigated the effects of treatment with bosentan, an ET A/ET B receptor antagonist, on the course of T. cruzi infection (Y strain) in C57Bl/6 mice. Treatment with bosentan (100 mg kg-1 day-1) was given per os starting day 0 after infection until sacrifice. Bosentan significantly increased myocardial inflammation, with no effects on parasitemia. Although the total number of nests was similar, a lower number of intact amastigote nests was found in the heart of bosentan-treated animals. Bosentan failed to affect the infection-associated increase in the cardiac levels of the cytokines IFN-g and TNF-a and the chemokines CCL2/MCP-1, CCL3/MIP-1a and CCL5/RANTES. In vitro, pre-incubation with ET-1 (0.1 microM) 4 h before infection enhanced the uptake of the parasites by peritoneal macrophages, and this effect was abrogated when macrophages were pre-treated with bosentan (1 microM) 15 min before incubation with ET-1. However, ET-1 did not alter killing of intracellular parasites after 48 h of in vitro infection. Our data suggest that bosentan-treated mice have a delay in controlling parasitism which is compensated for exacerbated inflammation. Infection is eventually controlled in these animals and lethality is unchanged, demonstrating that ET-1 plays a minor role in the protection against acute murine T. cruzi infection.

Topics: Acute Disease; Animals; Bosentan; Chagas Cardiomyopathy; Cytokines; Disease Models, Animal; Endothelin Receptor Antagonists; Endothelin-1; Male; Mice; Mice, Inbred C57BL; Parasitemia; Sulfonamides; Trypanosoma cruzi

On the basis of previous observations, endothelin 1 (ET-1) has been suggested as contributing to the pathogenesis of Chagasic cardiomyopathy. Therefore, ET-1flox/flox;alpha-MHC-Cre(+) mice in which the ET-1 gene was deleted from cardiac myocytes and ET-1flox/flox;Tie 2 Cre(+) mice in which the ET-1 gene was deleted from endothelial cells were infected with Trypanosoma cruzi. Genetic controls for these cell-specific ET-1 knockout mice were used. Ninety percentage of all mice survived acute infection with the Brazil strain and were evaluated 130 days postinfection. Inflammation and fibrosis were observed in all infected mice; however, fibrosis was reduced in ET-1flox/flox;alpha-MHC-Cre(+) mice. Cardiac magnetic resonance imaging revealed that infection resulted in a significant increase in right ventricular internal diameter (RVID) in all mice except ET-1flox/flox;alpha-MHC-Cre(+) mice; i.e., RVID was not changed in infected ET-1flox/flox;alpha-MHC-Cre(+) mice. Echocardiography of the left ventricle demonstrated increased left ventricular end-diastolic diameter, reduced fractional shortening, and decreased relative wall thickness in infected mice. However, the magnitude of the changes was significantly less in ET-1flox/flox;alpha-MHC-Cre(+) mice compared to other groups. These data provide further evidence of a role for ET-1, particularly cardiac myocyte-derived ET-1, in the pathogenesis of chronic Chagasic cardiomyopathy.

Topics: Animals; Chagas Cardiomyopathy; Chronic Disease; Echocardiography; Endothelin-1; Magnetic Resonance Imaging; Mice; Mice, Inbred C3H; Mice, Inbred C57BL; Parasitemia

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.

Topics: Acute Disease; Animals; Bradykinin; Chagas Cardiomyopathy; Endothelin Receptor Antagonists; Endothelin-1; Heart; Male; Models, Animal; Parasitemia; Perfusion; Rats; Rats, Sprague-Dawley; Receptor, Endothelin A; Vasodilator Agents

Trypanosoma cruzi is the aetiological agent of Chagas' disease, an important cause of chronic cardiomyopathy. We previously demonstrated a role for endothelin-1 (ET-1) in the pathogenesis of chagasic heart disease. In order to explore further the significance of ET-1 in chagasic heart disease, we infected ET-1 (flox/flox); alpha-MHC-Cre(+) (ET-1KO) mice, in which the ET-1 gene has been deleted from cardiac myocytes, with 10(4) T. cruzi (Brazil strain) trypomastigotes. As controls, we used ET-1 (flox/flox);Cre(-) (FLOX) and C57BL/6x129sv (WT) mice. All mice survived and were evaluated 150-160 days post-infection. Cardiac magnetic resonance imaging revealed a significant increase in right ventricular internal diameter in all infected animals except ET-1KO mice (control WT, 1.6+/-0.10 mm; infected WT, 2.8+/-0.15 mm; control FLOX, 2.04+/-0.02 mm; infected FLOX, 2.76+/-0.28 mm). There was no significant difference in right ventricular internal diameter between infected and uninfected ET-1KO mice (control ET-1KO, 1.83+/-0.11 mm; infected ET-1KO, 2.14+/-0.20 mm). In another series of experiments, transthoracic echocardiography was performed on uninfected as well as infected ET-1KO mice, and uninfected and infected FLOX mice. Both infected groups had an increased left ventricular end-diastolic diameter and reduced fractional shortening. In addition, relative wall thickness was also decreased in infected animals. However, the magnitude of these changes was less in infected ET-1KO mice. These data provide further support for a role for ET-1 in the pathogenesis of chronic chagasic heart disease, and indicate that cardiac myocytes are an important source of ET-1 in this disease.

Topics: Animals; Chagas Cardiomyopathy; Echocardiography; Endothelin-1; Magnetic Resonance Imaging; Male; Mice; Mice, Knockout; Myocardium

Topics: Adult; Chagas Cardiomyopathy; Chagas Disease; Chronic Disease; Endothelin-1; Female; Humans; Male; Middle Aged; Radioimmunoassay

Chagas' disease, caused by Trypanosoma cruzi, is an important cause of heart disease in Latin America. T. cruzi-induced microvascular compromise, in turn, is thought to play a major role in chagasic heart disease. Previous in vitro studies have implicated endothelin-1 (ET-1) as a potentially important vasomodulator present in increased levels in the supernatant of T. cruzi infected cultured human umbilical vein endothelial cells (HUVEC). Thus, the goal of the present investigation was to further evaluate the potentially important contribution of ET-1 to T. cruzi-induced alterations in vascular tone in vitro. Bioassay studies once again documented that exposure of isolated rat aortic rings to infected HUVEC supernatants elicited contractile responses whose steady-state magnitude was significantly greater than contractile responses elicited by exposure of aortic rings to uninfected HUVEC supernatants. Furthermore, the increased aortic contractility was significantly attenuated by the presence of the ET(A) subtype selective antagonists BMS-182,874 or BQ-123. Additionally, incubation of HUVEC with either verapamil or phosphoramidon prior to infection was also associated with reduced aortic contractility, upon exposure to the supernatant. Phosphoramidon, but not verapamil, produced a significant decrease in the measured ET-1 levels in the HUVEC supernatant. Consistent with the bioassay results, preincubation of Fura-2-loaded cultured rat aortic vascular smooth muscle cells with verapamil resulted in a near complete ablation of ET-1-induced transmembrane Ca2+ flux. Taken together, these data are consistent with the hypothesis that ET-1-induced vasoconstriction may play an important modulatory role in the vascular compromise characteristic of T. cruzi infection.

Topics: Animals; Aorta; Calcium; Cells, Cultured; Chagas Cardiomyopathy; Endothelin Receptor Antagonists; Endothelin-1; Endothelium, Vascular; Glycopeptides; Humans; Intracellular Fluid; Mice; Muscle Contraction; Muscle, Smooth, Vascular; Peptides, Cyclic; Protease Inhibitors; Rats; Receptor, Endothelin A; Trypanosoma cruzi; Vasoconstriction; Vasodilator Agents; Verapamil