Correlation between the cytokine profile and anticongestive medication in patients with chronic chagasic cardiopathy

Abstract INTRODUCTION: Chronic chagasic cardiopathy (CCC) is essentially a dilated cardiomyopathy in which a subacute, but constant chronic inflammatory process causes progressive destruction of the heart tissue. The action of proinflammatory cytokines, such as tumor necrosis factor alpha (TNF-α), interferon gamma (IFN-γ), and anti-inflammatory cytokines, like interleukin IL-10 and IL-17, plays a fundamental role in the immunopathogenesis and evolution of disease. Early anti-congestive therapy, aimed at changing the morbidity and mortality rate, has been shown to reduce disease progression and to alter patients' immune response pattern. METHODS: This cross-sectional study aimed to evaluate the profile of Th1 and Th17 cytokines and IL-17, TNF-α, and IFN-γ expressions in different stages of CCC. Forty patients affected by chronic Chagas disease were divided into different groups according to the stage of the pathology. In agreement with the Brazilian consensus on Chagas disease, patients were classified as presenting an undetermined form, a cardiac form and a digestive form. Serum IFN-γ, TNF-α, IL-10, and IL-17 were evaluated. RESULTS: Lower serum IFN-γ concentrations were detected in patients receiving angiotensin-converting enzyme inhibitors (p = 0.0182), but not in those using angiotensin receptor blockers (p = 0.0783). Patients using amiodarone and aldosterone antagonist presented higher serum TNF-α concentrations (p = 0.0106 and 0.0187, respectively). IL-10 and IL-17 levels did not differ between the study groups (p = 0.7273 and p = 0.6697, respectively). CONCLUSIONS: These results suggest that the cytokine profile and disease progression are altered by anti-congestive medications commonly prescribed for CCC.

Associação da capacidade de ligação e níveis séricos da Lectina de Ligação à Manose (MBL) à gravidade da cardiomiopatia chagásica crônica / Association of binding capacity and serum levels of mannose-binding lectin (MBL) with the severity of chronic Chagas cardiomyopathy

A doença de Chagas (DC) é uma infecção causada pelo Trypanosoma cruzi, é considerada endêmica na América Latina, afetando cerca de 15 milhões de indivíduos. Estima-se que cerca de 30 por cento das pessoas infectadas desenvolvem cardiomiopatia chagásica crônica, entre 5 à 30 anos após a infecção aguda. Com o objetivo de diferenciar portadores de DC com a evolução potencial para formas clínicas crônicas graves, pesquisadores tentam estabelecer marcadores biológicos de prognóstico da evolução da doença por meio de marcadores imunológicos. Lectina de Ligação a Manose (MBL) é uma molécula de reconhecimento de que a imunidade inata que desempenha um papel fundamental na defesa do hospedeiro, mediando a fagocitose e a destruição dos agentes patogénicos mediada pelo complemento. Existem vários estudos que enfatizam a relevância da MBL em diferentes doenças infecciosas, inflamatórias e auto-imunes. A deficiência de MBL pode implicar na susceptibilidade bacteriana, fúngica, por protozoários e infecções virais. Nosso objetivo foi investigar a associação dos níveis séricos e atividade de ligação da MBL com cardiomiopatia chagásica crônica, através da formação de um índice, que inferiu as moléculas ligantes. Para isso, foi feita uma avaliação, através de ELISA, dos níveis séricos e da capacidade de ligação da MBL, para formação desse índice de relação (Mbi), em pacientes crônicos assintomáticos e cardíacos da doença de Chagas. O estudo incluiu 77 pacientes portadores DC indeterminados (n = 19), cardíaco grave (n = 29) e cardíaco leve (n = 29)...

Effect of treatment with cyclophosphamide in low doses upon the onset of delayed type hypersensitivity in mice chronically infected with Trypanosoma cruzi: involvement of heart interstitial dendritic cells

Acute infection with Trypanosoma cruzi results in intense myocarditis, which progresses to a chronic, asymptomatic indeterminate form. The evolution toward this chronic cardiac form occurs in approximately 30% of all cases of T. cruzi infection. Suppression of delayed type hypersensitivity (DTH) has been proposed as a potential explanation of the indeterminate form. We investigated the effect of cyclophosphamide (CYCL) treatment on the regulatory mechanism of DTH and the participation of heart interstitial dendritic cells (IDCs) in this process using BALB/c mice chronically infected with T. cruzi. One group was treated with CYCL (20 mg/kg body weight) for one month. A DTH skin test was performed by intradermal injection of T. cruzi antigen (3 mg/mL) in the hind-footpad and measured the skin thickness after 24 h, 48 h and 72 h. The skin test revealed increased thickness in antigen-injected footpads, which was more evident in the mice treated with CYCL than in those mice that did not receive treatment. The thickened regions were characterised by perivascular infiltrates and areas of necrosis. Intense lesions of the myocardium were present in three/16 cases and included large areas of necrosis. Morphometric evaluation of lymphocytes showed a predominance of TCD8 cells. Heart IDCs were immunolabelled with specific antibodies (CD11b and CD11c) and T. cruzi antigens were detected using a specific anti-T. cruzi antibody. Identification of T. cruzi antigens, sequestered in these cells using specific anti-T. cruzi antibodies was done, showing a significant increase in the number of these cells in treated mice. These results indicate that IDCs participate in the regulatory mechanisms of DTH response to T. cruzi infection.

Prevalence of Trypanosoma cruzi antibodies and inflammatory markers in uncompensated heart failure / Prevalência de anticorpos anti-Trypanosoma cruzi e marcadores inflamatórios em pacientes com insuficiência cardíaca descompensada

INTRODUCTION: Heart failure (HF) represents the final stage of chronic chagasic cardiomyopathy (CChC). The diagnosis of CChC is based on the demonstration of anti-Trypanosoma cruzi antibodies (aTcAg) and clinical and epidemiological data. In Venezuela, there are no data about the prevalence of chagasic HF. The aim of this study was to determine the epidemiological, clinical, and inflammatory risk factors associated with seronegative or seropositive HF patients. METHODS: We performed a cross-sectional study in the Venezuelan central-west states among a healthy rural population and in patients admitted to the emergency room with uncompensated HF. RESULTS: The seroprevalence rates of Trypanosoma cruzi antibodies were 11.2 percent and 40.1 percent in the healthy population and in HF patients, respectively. Seropositivity in healthy individuals was associated with age, knowledge on triatomine vectors, and having seen wild reservoirs in the house; in HF patients, with contact with the vector and previous clinical diagnosis of Chagas' disease; and in both groups taken together, with age, knowledge on triatomines, and HF. Seropositive patients had prolonged QRS, decreased ejection fraction, and high serum magnesium, all significant as compared with HF seronegative cases. Left atrium enlargement and ventricular hypertrophy were most frequently observed in HF seronegative patients. CRP, IL6, ILβ1, IL2, and FNTα were elevated in 94.5 percent, 48 percent, 17.8 percent, 13.7 percent, and 6.9 percent of HF patients, respectively, but only IL2 levels were associated with chagasic HF. CONCLUSIONS: There is a high prevalence of aTcAg in HF patients from the central-west region of Venezuela, and their epidemiological, clinical, and inflammatory features are discreetly different as compared with those of seronegative cases.

INTRODUÇÃO: A insuficiência cardíaca (IC) representa o estágio final da cardiopatia chagásica crônica (CChC). O diagnóstico de CChC é baseado na demonstração de anticorpos anti-Trypanosoma cruzi (AgTc), dados clínicos e epidemiológicos. Na Venezuela, não há informação sobre a prevalência da IC chagásica. O objetivo deste estudo foi determinar fatores de risco epidemiológicos, clínicos e inflamatórios associados à IC chagásica. MÉTODOS: Realizamos um estudo prospectivo transversal em estados do centro-oeste da Venezuela em uma população rural saudável e em pacientes com IC descompensada. RESULTADOS: A soroprevalência de AgTc mostrou valores de 11,2 por cento e 40,1 por cento na população saudável e em pacientes com IC, respectivamente. A soropositividade de indivíduos sadios se associou com a idade, conhecimento de vetores e a observação de reservatórios silvestres na habitação. Em pacientes com IC, estavam relacionados ao contato com o vetor e ao diagnóstico clínico prévio de doença de Chagas. Em ambos os grupos juntos, a soropositividade foi associada com idade, conhecimento do vetor e com IC. Os pacientes soropositivos apresentavam prolongamento do intervalo QRS, fração de ejeção diminuída e magnésio sérico elevado. Aumento atrial esquerdo e hipertrofia ventricular foram as mais frequentemente observadas em pacientes com IC soronegativos. PCR, IL6, ILβ1, IL2 e FNTα foram elevados em 94,5, 48, 17,8, 13,7 e em 6,9 por cento dos pacientes com IC, respectivamente; os níveis de IL-2 foram associados com IC chagásica. CONCLUSÕES: Uma alta prevalência de AgTc foi observada em pacientes com IC na região centro-oeste da Venezuela, cujos aspectos epidemiológicos, clínicos e inflamatórios são discretamente diferentes dos soronegativos.

Chagas disease: Present status of pathogenic mechanisms and chemotherapy

There are approximately 7.8 million people in Latin America, including Chile, who suffer from Chagas disease and another 28 million who are at risk of contracting it. Chagas is caused by the flagellate protozoan Trypanosoma cruzi. It is a chronic disease, where 20 percent-30 percent of infected individuals develop severe cardiopathy, with heart failure and potentially fatal arrhythmias. Currently, Chagas disease treatment is more effective in the acute phase, but does not always produce complete parasite eradication during indeterminate and chronic phases. At present, only nifurtimox or benznidazole have been proven to be superior to new drugs being tested. Therefore, it is necessary to find alternative approaches to treatment of chronic Chagas. The current treatment may be rendered more effective by increasing the activity of anti-Chagasic drugs or by modifying the host's immune response. We have previously shown that glutathione synthesis inhibition increases nifurtimox and benznidazole activity. In addition, there is increasing evidence that cyclooxygenase inhibitors present an important effect on T. cruzi infection. Therefore, we found that aspirin reduced the intracellular infection in RAW 264.7 cells and, decreased myocarditis extension and mortality rates in mice. However, the long-term benefit of prostaglandin inhibition for Chagasic patients is still unknown.

Clinical and laboratory status of patients with chronic Chagas disease living in a vector-controlled area in Minas Gerais, Brazil, before and nine years after aetiological treatment

Twenty-eight Chagas disease patients (CD), 22 with the indeterminate clinical form (IND) and six with the cardiac or digestive form (CARD/DIG), were treated with benznidazole and underwent clinical and laboratorial analysis before (IND and CARD/DIG) and nine years after [patients after treatment (CDt), patients with the indeterminate clinical form at treatment onset (INDt) and with the cardiac or digestive form at treatment onset (CARD/DIGt)] treatment. The data demonstrate that 82.1 percent of CDt patients (23/28) remained clinically stable and 95.4 percent of the INDt (21/22) and 33.3 percent of the CARD/DIGt (2/6) patients showed unaltered physical and laboratorial examinations. The clinical evolution rate was 2 percent/year and was especially low in INDt patients (0.5 percent/year) relative to CARD/DIGt patients (7.4 percent/year). Positive haemoculture in treated patients was observed in 7.1 percent of the cases. None of the INDt (0/21) and 33.3 percent of the CARD/DIGt (2/6) patients displayed positive cultures. The PCR presented a positive rate significantly higher (85.2 percent, 23/27) than haemoculture and two samples from the same patient revealed the same result 57.7 percent of the patients. Conventional serology-ELISA on 16 paired samples remained positive in all individuals. Semi-quantitative ELISA highlighted significant decreases in reactivity, particularly in INDt relative to IND. Non-conventional serology-FC-ALTA-IgG, after treatment, showed positive results in all sera and 22 paired samples examined at seven and nine years after treatment, demonstrated significantly lower reactivity, particularly in INDt patients. This study was retrospective in nature, had a low number of samples and lacked an intrinsic control group, but the data corroborate other results found in the literature. The data also demonstrate that, even though a cure has not been detected in the none-treated patients, the benefits for clinical evolution ...

Trypanosoma cruzi: parasite antigens sequestered in heart interstitial dendritic cells are related to persisting myocarditis in benznidazole-treated mice

We investigated whether sequestered Trypanosoma cruzi antigens found in heart interstitial dendritic cells (IDCs) contribute to the residual myocarditis found in mice following treatment with benznidazole, a specific chemotherapeutic drug. IDCs are antigen-presenting cells that are MHC-II-receptor dependent. Swiss mice were divided into two experimental groups: the 1st group was infected with the Colombian strain of T. cruzi, which is resistant to treatment with benznidazole, and the 2nd group was infected with clone 21SF-C 3, which has a medium susceptibility to the drug. Treatment of the Colombian strain group started on the 120th day post-infection and for the 21SF-C3 strain group treatment was started on the 90th day. In both groups, treatment lasted for 90 days. The animals were sacrificed either 150 or 200 days post-treatment. The myocardium was analysed by immunohistochemistry using anti-MAC3, 33D1, CD11b and CD11c monoclonal antibodies for IDCs or anti-T. cruzi purified antibodies. Parasite antigens were expressed on the IDC membranes in both treated and untreated mice. Myocarditis subsided following treatment, evidenced by both histological and morphometrical evaluation. A reduction in the number of IDCs carrying T. cruzi antigens in the treated group indicates that the elimination of parasites influences antigen presentation with concomitant decreases in inflammation. There is a correlation between the presence of T. cruzi antigens in these cells and the chronic focal, residual myocarditis seen in treated mice.

Back to the future in Chagas disease: from animal models to patient cohort studies, progress in immunopathogenesis research

Despite the wealth of information generated by trans-disciplinary research in Chagas disease, knowledge about its multifaceted pathogenesis is still fragmented. Here we review the body of experimental studies in animal models supporting the concept that persistent infection by Trypanosoma cruzi is crucial for the development of chronic myocarditis. Complementing this review, we will make an effort to reconcile seemingly contradictory results concerning the immune profiles of chronic patients from Argentina and Brazil. Finally, we will review the results of molecular studies suggesting that parasite-induced inflammation and tissue damage is, at least in part, mediated by the activities of trans-sialidase, mucin-linked lipid anchors (TLR2 ligand) and cruzipain (a kinin-releasing cysteine protease). One hundred years after the discovery of Chagas disease, it is reassuring that basic and clinical research tends to converge, raising new perspectives for the treatment of chronic Chagas disease.

Chronic Trypanosoma cruzi-elicited cardiomyopathy: from the discovery to the proposal of rational therapeutic interventions targeting cell adhesion molecules and chemokine receptors: how to make a dream come true

One hundred years ago, Carlos Chagas discovered a new disease, the American trypanosomiasis. Chagas and co-workers later characterised the disease's common manifestation, chronic cardiomyopathy, and suggested that parasitic persistence coupled with inflammation was the key underlying pathogenic mechanism. Better comprehension of the molecular mechanisms leading to clinical heart afflictions is a prerequisite to developing new therapies that ameliorate inflammation and improve heart function without hampering parasite control. Here, we review recent data showing that distinct cell adhesion molecules, chemokines and chemokine receptors participate in anti-parasite immunity and/or detrimental leukocyte trafficking to the heart. Moreover, we offer evidence that CC-chemokine receptors may be attractive therapeutic targets aiming to regain homeostatic balance in parasite/host interaction thereby improving prognosis, supporting that it is becoming a non-phantasious proposal.

Immunological and non-immunological effects of cytokines and chemokines in the pathogenesis of chronic Chagas disease cardiomyopathy

The pathogenesis of Chagas disease cardiomyopathy (CCC) is not well understood. Since studies show that myocarditis is more frequent during the advanced stages of the disease, and the prognosis of CCC is worse than that of other dilated cardiomyopathies of non-inflammatory aetiology, which suggest that the inflammatory infiltrate plays a major role in myocardial damage. In the last decade, increasing evidence has shown that inflammatory cytokines and chemokines play a role in the generation of the inflammatory infiltrate and tissue damage. CCC patients have an increased peripheral production of the inflammatory Th1 cytokines IFN-³ and TNF-± when compared to patients with the asymptomatic/indeterminate form. Moreover, Th1-T cells are the main producers of IFN-³ and TNF-± and are frequently found in CCC myocardial inflammatory infiltrate. Over the past several years, our group has collected evidence that shows several cytokines and chemokines produced in the CCC myocardium may also have a non-immunological pathogenic effect via modulation of gene and protein expression in cardiomyocytes and other myocardial cell types. Furthermore, genetic polymorphisms of cytokine, chemokine and innate immune response genes have been associated with disease progression. We will review the molecular and immunological mechanisms of myocardial damage in human CCC in light of recent findings.

Immunological imbalance between IFN-³ and IL-10 levels in the sera of patients with the cardiac form of Chagas disease

The immune response is crucial for protection against disease; however, immunological imbalances can lead to heart and digestive tract lesions in chagasic patients. Several studies have evaluated the cellular and humoral immune responses in chagasic patients in an attempt to correlate immunological findings with clinical forms of Chagas disease. Moreover, immunoglobulins and cytokines are important for parasitic control and are involved in lesion genesis. Here, cytokine and IgG isotype production were studied, using total epimastigote antigen on sera of chagasic patients with indeterminate (IND, n = 27) and cardiac (CARD, n = 16) forms of the disease. Samples from normal, uninfected individuals (NI, n = 30) were use as controls. The results showed that sera from both IND and CARD patients contained higher levels of Trypanosoma cruzi-specific IgG1 (IgG1) antibodies than sera from NI. No difference in IgG2 production levels was observed between NI, IND and CARD patients, nor was a difference in IL-10 and IFN-³ production detected in the sera of IND, CARD and NI patients. However, IND patients displayed a positive correlation between IL-10 and IFN-³ levels in serum, while CARD patients showed no such correlation, indicating an uncontrolled inflammatory response in CARD patients. These findings support the hypothesis that a lack of efficient regulation between IFN-³ and IL-10 productions in CARD patients may lead to cardiac immunopathology.

TNF/TNFR1 signaling up-regulates CCR5 expression by CD8+ T lymphocytes and promotes heart tissue damage during Trypanosoma cruzi infection: beneficial effects of TNF-á blockade

In Chagas disease, understanding how the immune response controls parasite growth but also leads to heart damage may provide insight into the design of new therapeutic strategies. Tumor necrosis factor-alpha (TNF-á) is important for resistance to acute Trypanosoma cruzi infection; however, in patients suffering from chronic T. cruzi infection, plasma TNF-á levels correlate with cardiomyopathy. Recent data suggest that CD8-enriched chagasic myocarditis formation involves CCR1/CCR5-mediated cell migration. Herein, the contribution of TNF-á, especially signaling through the receptor TNFR1/p55, to the pathophysiology of T. cruzi infection was evaluated with a focus on the development of myocarditis and heart dysfunction. Colombian strain-infected C57BL/6 mice had increased frequencies of TNFR1/p55+ and TNF-á+ splenocytes. Although TNFR1-/- mice exhibited reduced myocarditis in the absence of parasite burden, they succumbed to acute infection. Similar to C57BL/6 mice, Benznidazole-treated TNFR1-/- mice survived acute infection. In TNFR1-/- mice, reduced CD8-enriched myocarditis was associated with defective activation of CD44+CD62Llow/- and CCR5+ CD8+ lymphocytes. Also, anti-TNF-á treatment reduced the frequency of CD8+CCR5+ circulating cells and myocarditis, though parasite load was unaltered in infected C3H/HeJ mice. TNFR1-/- and anti-TNF-á-treated infected mice showed regular expression of connexin-43 and reduced fibronectin deposition, respectively. Furthermore, anti-TNF-á treatment resulted in lower levels of CK-MB, a cardiomyocyte lesion marker. Our results suggest that TNF/TNFR1 signaling promotes CD8-enriched myocarditis formation and heart tissue damage, implicating the TNF/TNFR1 signaling pathway as a potential therapeutic target for control of T. cruzi-elicited cardiomyopathy.

Chagas disease cardiomyopathy: current concepts of an old disease

Chagas disease continues to be a significant public health problem, as ca. 10 million people are still infected with T. cruzi in Latin America. Decades after primary infection, 30 percent of individuals can develop a form of chronic inflammatory cardiomyopathy known as Chagas disease cardiomyopathy (CCC). Data from both murine models and human studies support the view that an autoimmune response as well as a parasite-driven immune response involving inflammatory cytokines and chemokines may both play a role in generating the heart lesions leading to CCC. This review aims to summarize recent advances in the understanding of the immunopathogenesis of Chagas disease cardiomyopathy.

A doença de Chagas continua sendo importante problema de saúde pública uma vez que cerca de 10 milhões de indivíduos ainda estão infectados pelo T. cruzi. Décadas após a infecção primária, aproximadamente 30 por cento dos indivíduos podem desenvolver uma cardiomiopatia inflamatória crônica, a chamada Cardiomiopatia Chagásica Crônica (CCC). Dados de modelos murinos e de estudos em humanos apóiam a visão de que tanto respostas auto-imunes como as determinadas pelo parasita em conjunto com citocinas e quimiocinas inflamatórias participam da geração das lesões cardíacas típicas da CCC. A presente revisão tem como objetivo sumarizar os recentes avanços no entendimento da imunopatogênese da Cardiomiopatia Chagásica Crônica.

Chagas disease as a mechanistic model for testing a novel hypothesis

The association between depression and cardiovascular disease is well documented. Nevertheless, the process through which they are linked remains unknown, as does the direction of this relationship. Studies have suggested both that depression is a risk factor for heart disease and that heart disease is a risk factor for depression. A number of studies have established that a relationship exists between depression and inflammation, with alterations in the levels of inflammatory markers (IL-1, IL-6, TNF-alpha and others). Depressive symptoms have also been identified in many diseases characterized by inflammatory processes e.g. rheumatoid arthritis, bronchial asthma, diabetes, tuberculosis and cardiovascular diseases. In this brief viewpoint, we explain and propose how to use Chagas disease, a disorder characterized by inflammatory processes and leading to cardiovascular and autonomic problems, as a model for studying the directionality of the relationship between heart disease and depression.

A associação entre depressão e doença cardiovascular está bem documentada. Não obstante, o processo pelo qual está associada permanece desconhecido, assim como o sentido desta associação. Estudos têm sugerido que tanto a depressão é um fator de risco para a doença cardiovascular quanto esta o é para a depressão. Uma série de trabalhos tem estabelecido que uma relação existe entre depressão e inflamação, com alterações evidenciadas por marcadores de inflamação (IL-1, IL-6, TNF alfa e outros). Sintomas de depressão também têm sido identificados em diversas doenças caracterizadas por processos inflamatórios, tais como artrite reumatoide, asma brônquica, diabete, tuberculose e doenças cardiovasculares. Nesta breve opinião é explicitado e proposto como empregar a doença de Chagas, um agravo caracterizado por processos inflamatórios e indutor de problemas cardiovasculares e autonômicos, como um modelo de estudo da direcionalidade da relação entre doença cardíaca e depressão.

Pacientes chagásicos crônicos portadores de disfunção do nódulo sinusal: a presença de anticorpos IgG com ação agonista muscarínica independe da disfunção ventricular esquerda? / Chronic Chagas disease patients with sinus node dysfunction: is the presence of IgG antibodies with muscarinic agonist action independent of left ventricular dysfunction?

Estudos mostram que anticorpos IgG agonistas muscarínicos, de pacientes chagásicos, alteram a atividade elétrica de células cardíacas in vitro. Outros consideram sua presença, e a da síndrome do nódulo sinusal, conseqüências da lesão cardíaca progressiva. Objetivou-se avaliar a relação entre os anticorpos e as disfunções nodal e ventricular esquerda, em 65 pacientes chagásicos crônicos divididos em grupo I, composto de 31 pacientes portadores da síndrome do nódulo sinusal, e grupo II, de não portadores. A análise dos dados, pelo modelo log linear, mostrou uma interdependência entre a disfunção do nódulo sinusal e os anticorpos (p=0,0021) e entre a disfunção nodal e a ventricular (p=0,0005), mas não houve relação entre esta última e os anticorpos. Idade e sexo não tiveram influência sobre as outras variáveis. Chagásicos crônicos com a síndrome do nódulo sinusal têm maior prevalência de anticorpos agonistas muscarínicos, independentemente da presença de disfunção miocárdica.

Studies have shown that muscarinic agonist IgG antibodies from Chagas disease patients alter the electrical activity of cardiac cells in vitro. Others have considered their presence, along with sinus node dysfunction, to be consequences of progressive cardiac lesions. The aim of this study was to evaluate the relationship between these antibodies and sinus node and left ventricular dysfunction in 65 chronic Chagas disease patients. These patients were divided into group I, composed of 31 patients with sinus node dysfunction, and group II, composed of the patients without this syndrome. Data analysis using the log linear model showed interdependence between sinus node dysfunction and the antibodies (p = 0.0021) and between nodal and ventricular dysfunction (p = 0.0005). However, no relationship was found between the antibodies and ventricular function. Age and sex did not influence any other variables. The chronic Chagas disease patients with sinus node dysfunction had higher prevalence of muscarinic agonist antibodies, independent of the presence of myocardial dysfunction.

Trypanosoma cruzi high infectivity in vitro is related to cardiac lesions during long-term infection in Beagledogs

Trypanosoma cruzi is a hemoflagelate parasite associated with heart dysfunctions causing serious problems in Central and South America. Beagle dogs develop the symptoms of Chagas disease in humans, and could be an important experimental model for better understanding the immunopathogenic mechanisms involved in the chagasic infection. In the present study we investigated the relation among biological factors inherent to the parasite (trypomastigote polymorphism and in vitro infectivity) and immunoglobulin production, inflammation, and fibrosis in the heart of Beagle dogs infected with either T. cruzi Y or Berenice-78 strains. In vitro infectivity of Vero cells as well as the extension of cardiac lesions in infected Beagle was higher for Y strain when compared to Berenice-78 strain. These data suggested that in vitro infectivity assays may correlate with pathogenicity in vivo. In fact, animals infected with Y strain, which shows prevalence of slender forms and high infectivity in vitro, presented cardiomegaly, inflammation, and fibrosis in heart area. Concerning the immunoglobulin production, no statistically significant difference was observed for IgA, IgM or IgG levels among T. cruzi infected animals. However, IgA together IgM levels have shown to be a good marker for the acute phase of Chagas disease.

Producción de interferón gamma por linfocitos pas-positivos infiltrados en corazones de pacientes chagasicos en los sitos de lesiones / Interferon gamma production by pas-positive T Lymphocytes of chagastic patients infiltrated into human hearts in the sites of lesions

En sangre de chagásicos en trabajos previos se halló un número alto de linfocitos T productores de substancia P.A.S.- positiva, más numerosos en chagásicos con electrocardiograma anormal. Luego los hallamos infiltrados en el corazón chagásico. En este trabajo consideramos nuestra hipótesis de que esa substancia linfocitaria sería Interferongamma. Material y Métodos. Muestras de corazones de 8 chagásicos fallecidos por muerte cardiaca. Se utilizaron anticuerpos monoclonales anti-IFN gamma humano; para linfocitos T activados (CD45 ROJ, y la reacción del P.A.S, respectivamente. Las células positivas se contaron en 50 campos a 400x y el estado de miocardio se comparó con datos clínicos. También. en frotis de sangre de pacientes chagásicos con ECG anormal, investigamos inmunomarcación con anti interferon gamma y la P.A.S.-positividad, respectivamente. Resultados El mayor número de células infiltrantes intracardiacas (65-75%) resultaron positivos para IFN gamma, y similares valores para P.A.S.-positividad y para CD45 RO. En sangre hallamos 41 % ±7 de linfocitos P.A.S.-positivos: y similar de positivos para IFN-gamma. Conclusiones: Los datos muestran que los linfocitos P.A.S.-positivos de los chagásicos producen IFN-gamma tanto en sangre. Como infiltrados en tejidos cardíacos. e indican una fuerte respuesta T-helper l. También explican la gran afluencia de macrófagos en dichos tejidos cardíacos. No se vieron parásitos T. cruzi ni formas intracelulares. Esos hechos refuerzan los datos que indican existencia de autoinmunidad en Chagas. Abrimos una pregunta: ¿a que antígeno/s responden en el corazón chagásico los linfocitos T P.A.S.-positivos productores de IFN-gamma?

In the blood of chagasic patients, a high number of T-lymphocytes producers of a P.A.S.-positive substance was found, more numerous in chagasics with abnormal electrocardiogram. Further. We found such lymphocytes infiltrated in the chagasic heart. Here, we considered our hypothesis that those lymphocytes would be Interferon -gamma producer' cells. Material and Methods: Heart samples of 8 patients deceased due to chagasic heart disease (ChHD). Cuts of 5 microns were submitted to monoclonal antibodies for human Interferon-gamma; to CD45RO for activated T lymphocytes; and to the classical Periodic acid Schiff reaction (P.A.S.), respectively. In blood smears from chagasic patients with ChHD, the reactivity for anti Interferon gamma and for the P.A.S. reaction was compared, regarding the respective positive cell number. The myocardium status was compared with clinical date. Results: In hearts, 65-75% of infiltrated lymphocytes were positive for IFN-gamma; similar values were found, in seriated cuts, of P.A.S.-positive lymphocytes, as well as of CD45RO+. In blood, there were 41 % ±9 of P.A.S.positive lymphocytes, similar to positive cells for IFN-gamma. Conclusions: The data indicates that the P.A.S.-positive lymphocytes from chagasic patients are producers of IFN gamma in blood, as well as when infiltrated into the cardiac tissues. Such fact explains also the great affluence of macrophages in cardiac tissues in ChHD. The data indicate a strong response of T helper 1 type in this severe advanced stage of Chagas'disease. Either Trypanosome cruzi parasites or intracellular forms were seen in these hearts. This favours the data showing autoimmune mechanisms in this process. We open a question: to which antigen/s respond in the chagasic hearts the lymphocytes producers of IFN gamma?

An overview of chagasic cardiomyopathy: pathogenic importance of oxidative stress

Há evidências que sugerem que as miocardites chagásicas são devidas aos danos induzidos pelo estresse oxidativo, podendo contribuir para a evolução da doença de Chagas. Em doenças infecciosas, a formação de espécies reativas do oxigênio (ROS) é, principalmente, derivada de danos celulares mediados pela invasão e replicação do patógeno e por reações citotóxicas mediadas pelo sistema imune. No entanto, como as ROS são formadas e sua função no estresse oxidativo na cardiomiopatia chagásica (CCM) não estão completamente elucidadas. Nesta revisão, nós discutimos as evidências para o aumento do estresse oxidativo na doença de Chagas, com ênfase nas anormalidades mitocondriais, na disfunção da cadeia de transporte de elétrons e seu papel na manutenção do estresse oxidativo no miocárdio. Discutimos ainda, os resultados da literatura que relatam as conseqüências da manutenção do estresse oxidativo na patogênese da CCM.