[Sera levels of anti-Trypanosoma cruzi IgG in the course of chronic chagasic cardiopathy in 10 years]

Insights from the use of erythropoietin in experimental Chagas disease

In addition to the long-established role in erythropoiesis, erythropoietin (Epo) has protective functions in a variety of tissues, including the heart. This is the most affected organ in chronic Chagas disease, caused by the protozoan Trypanosoma cruzi. Despite seven million people being infected with T. cruzi worldwide, there is no effective treatment preventing the disease progression to the chronic phase when the pathological involvement of the heart is often observed. Chronic chagasic cardiomyopathy has a wide variety of manifestations, like left ventricular systolic dysfunction, dilated cardiomyopathy, and heart failure. Since Epo may help maintain cardiac function by reducing myocardial necrosis, inflammation, and fibrosis, this study aimed to evaluate whether the Epo has positive effects on experimental Chagas disease. For that, we assessed the earlier (acute phase) and also the later (chronic phase) use of Epo in infected C57BL/6 mice. Blood cell count, biochemical parameters, parasitic load, and echocardiography data were evaluated. In addition, histopathological analysis was carried out. Our data showed that Epo had no trypanocide effect nor did it modify the production of anti-T. cruzi antibodies. Epo-treated groups exhibited parasitic burden much lower in the heart compared to blood. No pattern of hematological changes was observed combining infection with treatment with Epo. Chronic Epo administration reduced CK-MB serum activity from d0 to d180, irrespectively of T. cruzi infection. Likewise, echocardiography and histological results indicate that Epo treatment is more effective in the chronic phase of experimental Chagas disease. Since treatment is one of the greatest challenges of Chagas disease, alternative therapies should be investigated, including Epo combined with benznidazole.

Effects of homeopathy in mice experimentally infected with Trypanosoma cruzi

Aim: The aim of this study was to evaluate the action of homeopathic treatment on mice experimentally infected with Trypanosoma cruzi.

Methods: Eighty adult male C57BL/6 inbred mice were randomly allocated to five groups treated with biotherapy (nosode) of T. cruzi 12dH (12×) pre- and post-infection; Phosphorus 12dH post-infection; infected control treated with control solution and uninfected control. The biotherapy was prepared by the Costa method from the blood of mice experimentally infected with the Y strain of T. cruzi. Phosphorus was used because of its clinical and reportorial similarity to Chagas disease. T. cruzi (104) sanguineous forms were inoculated intraperitoneally per animal. Parasitaemia was monitored, leukocyte and serological responses were evaluated at 0, 7, 14 and 42 days after infection. The prepatent and patent periods of parasitaemia, maximum of parasitaemia, day of maximum parasitaemia and mortality rates were compared between groups.

Results: A significantly shorter period of patent parasitaemia was observed in the group treated with the biotherapy before infection (p < 0.05) than in the other groups. This group also had the lowest parasitaemias values at 9, 13, 15 (p < 0.05), 17 (p < 0.05), 22, 24 and 28 days, a lower rate of mortality and a significant increase of lymphocytes compared to the infected control group. The Phosphorus group had the longest period of patent parasitaemia, higher maximum parasitaemia, and a significant reduction of lymphocyte numbers, but no mortality. The infected control group had the highest mortality rate (not statistically significant), and the highest IgG titres at 42 days post-infection (p < 0.05).

Conclusions: The results suggest that pre-treatment with biotherapy modulates host immune response to T. cruzi, mainly during the acute phase of the infection. Phosphorus shows an action on the pathogenicity by T. cruzi infection. Homeopathic treatment of T. cruzi infection should be further investigated.

Evolution of anti-Trypanosoma cruzi antibody production in patients with chronic Chagas disease: Correlation between antibody titers and development of cardiac disease severity

Chagas disease is one of the most important endemic infections in Latin America affecting around 6–7 million people. About 30–50% of patients develop the cardiac form of the disease, which can lead to severe cardiac dysfunction and death. In this scenario, the identification of immunological markers of disease progression would be a valuable tool for early treatment and reduction of death rates. In this observational study, the production of anti-Trypanosoma cruzi antibodies through a retrospective longitudinal follow-up in chronic Chagas disease patients´ cohort and its correlation with disease progression and heart commitment was evaluated. Strong inverse correlation (ρ = -0.6375, p = 0.0005) between anti-T. cruzi IgG₁ titers and left ventricular ejection fraction (LVEF) in chronic Chagas cardiomyopathy (CCC) patients were observed after disease progression. Elevated levels of anti-T. cruzi IgG₃ titers were detected in all T. cruzi-infected patients, indicating a lack of correlation of this IgG isotype with disease progression. Furthermore, low levels of anti-T. cruzi IgG₂, IgG₄, and IgA were detected in all patients through the follow-up. Although without statistical significance anti-T. cruzi IgE tends to be more reactive in patients with the indeterminate form (IND) of the disease (p = 0.0637). As this study was conducted in patients with many years of chronic disease no anti-T. cruzi IgM was detected. Taken together, these results indicate that the levels of anti-T. cruzi IgG₁ could be considered to seek for promising biomarkers to predict the severity of chronic Chagas disease cardiomyopathy.

Trypanosoma cruzi is the etiological agent of Chagas disease that affects about 7 million people in Latin America, being considered one of the most important neglected diseases of developing countries. Chronic Chagas disease might be present in different forms as an asymptomatic indeterminate form or even with severe cardiac commitment, known as chronic Chagas cardiomyopathy. In fact, the cardiac form can lead to death due to disease progression. Seeking for biomarkers of cardiomyopathy progression has become important to understand the cardiac progression and to predict or even prevent the disease worsening and to improve the quality of life of affected individuals. In this work, we followed the anti-T. cruzi antibody profile in a retrospective longitudinal study in a cohort of chronic Chagas disease patients, and further correlate with heart commitment and cardiac disease progression. We found an inverse correlation between anti-T. cruzi IgG₁ titers and cardiac disease severity in patients with progressive disease. These data suggest that anti-T. cruzi IgG₁ levels could be considered a suitable candidate tool for early identification of cardiac disease progression.

Evaluation of Parasiticide Treatment with Benznidazol in the Electrocardiographic, Clinical, and Serological Evolution of Chagas Disease

INTRODUCTION

Chagas disease is one of the most important endemic parasitic diseases in Latin America. In its chronic phase, progression to cardiomyopathy has high morbidity and mortality. The persistence of a normal electrocardiogram (ECG) provides a similar prognosis to that of a non-diseased population. Benznidazole (BNZ) is the only drug with trypanocidal action available in Brazil.

MATERIALS/METHODS/RESULTS

A group of 310 patients with chronic Chagas disease who had normal ECGs at the first medical visit performed before 2002 were included. There were 263 patients treated with BNZ and 47 untreated. The follow-up period was 19.59 years. Univariate analyses showed that those treated were younger and predominantly male. As many as 79.08% of those treated and 46.81% of those untreated continued with normal electrocardiograms (p <0.0001). The occurrence of electrocardiographic abnormalities and relevant clinical events (heart failure, stroke, total mortality, and cardiovascular death) was less prevalent in treated patients (p <0.001, p: 0.022, p: 0.047 respectively). In multivariate analyses, the parasiticide treatment was an independent variable for persistence of a normal ECG pattern, which was an independent variable in the prevention of significant clinical events. The immunofluorescence titers decreased with the parasitological treatment. However, the small number of tests in untreated patients did not allow the correlation of the decrease of these titers with electrocardiographic alterations.

CONCLUSION

These data suggest that treatment with benznidazole prevents the occurrence of electrocardiographic alterations. On the other hand, patients who develop ECG abnormalities present with more significant clinical events.

Clinical and serological evolution in chronic Chagas disease patients in a 4-year pharmacotherapy follow-up: a preliminary study

INTRODUCTION

The role of trypanocidal therapy in the chronic phase of Chagas disease remains controversial.

METHODS

A total of 13 patients with chronic Chagas disease were treated with benznidazole (5mg/kg/day/60 days) and surveyed via antibody measurement and conventional electrocardiogram over the course of 4 years.

RESULTS

The antibody titers were significantly reduced after 4 years (p<0.05). Most of the patients showed maintenance of the initial clinical picture (electrocardiographic), with the exception of 4 cases.

CONCLUSIONS

Although trypanocidal therapy in the chronic phase of Chagas disease was of limited effectiveness, we believe that it is beneficial in treating these patients.

Morbidade da doença de Chagas em pacientes autóctones da microrregião do Rio Negro, Estado do Amazonas

INTRODUÇÃO: Foi realizado um estudo soroepidemiológico e clínico em 152 indivíduos residentes no município de Barcelos, Estado do Amazonas. Avaliou-se a soroprevalência da infecção chagásica e a morbidade da doença de Chagas. MÉTODOS: Os testes sorológicos foram a imunofluorescência indireta, ELISA convencional e recombinante e o Tesa-blot. Foram considerados soropositivos 38 pacientes, duvidosos 31 e soronegativos negativos 83. Os 38 casos soropositivos foram pareados com 38 controles soronegativos da mesma idade, sexo e submetidos à avaliação epidemiológica, clínica, eletro e ecocardiográfica, sendo que, 29 pares fizeram exame radiológico do esôfago. RESULTADOS: A soropositividade foi 19,9 vezes mais frequente nos trabalhadores do extrativismo em geral e 10,4 vezes mais frequente no extrativismo da piaçaba. Aplicou-se o teste de reconhecimento com o vetor local do gênero Rhodnius e 86,7% dos pacientes soropositivos o reconheceram, enquanto somente 34,2% dos soronegativos o fizeram. O ECG mostrou-se alterado em 36,8% nos soropositivos e em 21,5% nos soronegativos, enquanto o ecocardiograma mostrou alterações em 31,6% nos soropositivos e 18,4% nos soronegativos. Precordialgia e palpitações foram mais frequentes nos soropositivos. O estudo clínico do aparelho digestivo e radiológico do esôfago não mostrou alterações significativas. CONCLUSÕES. A doença de Chagas na região estudada pode ser considerada uma doença ocupacional.

Trypanosoma cruzi: Genetic diversity influences the profile of immunoglobulins during experimental infection

The clonal evolution model postulated for Trypanosoma cruzi predicts a correlation between the phylogenetic divergence of T. cruzi clonal genotypes and their biological properties. In the present study, the linkage between phylogenetic divergence of the parasite and IgG, IgG1, IgG2a and IgG2b response has been evaluated during the acute and chronic phases of the experimental infection. Eight laboratory-cloned stocks representative of this phylogenetic diversity and including the lineages T. cruzi I (genotypes 19 and 20), T. cruzi II (genotype 32) and T. cruzi (genotype 39) have been studied. The results showed that the pattern of humoral immune response was correlated with T. cruzi genotype, and that stocks included in genotype 20 were responsible for the high IgG response in the acute and chronic phases. Moreover, T. cruzi I lineage was more efficient in over-expressing all subclasses of specific anti-parasite IgG than either T. cruzi II or T. cruzi lineages. Curiously, the alteration in the pattern of antibodies induced by Benznidazole treatment was related to the phase of the infection but not to the genotype of the parasite. The data suggest that genotypes of T. cruzi are able to drive levels/subclasses of specific IgG, hence giving rise to further concerns about the sensitivity of serological assays in the diagnosis of human Chagas disease.

International meeting: new diagnostic tests are urgently needed to treat patients with Chagas disease

Trypanosoma cruzi infection is often not detected early on or actively diagnosed, partly because most infected individuals are either asymptomatic or oligosymptomatic. Moreover, in most places, neither blood banks nor healthcare units offer diagnostic confirmation or treatment access. By the time patients present clinical manifestations of advanced chronic Chagas disease, specific treatment with current drugs usually has limited effectiveness. Better-quality serological assays are urgently needed, especially rapid diagnostic tests for diagnosis patients in both acute and chronic phases, as well as for confirming that a parasitological cure has been achieved. Some new antigen combinations look promising and it is important to assess which ones are potentially the best, together with their requirements in terms of investigation and development. In August 2007, a group of specialized researchers and healthcare professionals met to discuss the state of Chagas infection diagnosis and to build a consensus for a plan of action to develop efficient, affordable, accessible and easy-to-use diagnostic tests for Chagas disease. This technical report presents the conclusions from that meeting.

Chagas' disease: IgG isotypes against cytoplasmic (CRA) and flagellar (FRA) recombinant repetitive antigens of Trypanosoma cruzi in chronic Chagasic patients

The wide range of clinical Chagas' disease manifestations, of which heart involvement is the most significant, because of its characteristics, frequency and consequences, and lack of treatment and cure, justify research in this area. Specific immunoglobulin G (IgG) antibody subclasses have been associated with human Chagas' disease. Thus, in this study, the profile of IgG subclasses against cytoplasmic (CRA) and flagellar (FRA) recombinant repetitive T. cruzi-specific antigens was correlated with cardiac (CARD, n=33), cardiodigestive (CD, n=7), and indeterminate (IND, n=20) forms of Chagas' disease by indirect enzyme-linked immunosorbent assay (ELISA). IgG subclasses were detected in almost all Chagas patients studied. Nevertheless, only specific IgG2 isotype FRA was found with a significant statistical difference in CARD patients when compared to IND patients. This result suggests the potential use of this isotype for prognostic purposes, for monitoring the progression of chronic Chagas' disease, and for predicting the risk of CARD damage. This is important information, as it could help physicians to evaluate and manage the treatment of their patients. However, a follow-up study is necessary to confirm our result.

Mechanical and energetic effects of chronic chagasic patients' antibodies on rat myocardium

Chagasic (Ch) and nonchagasic (NCh) IgG fraction (20 microg/ml) effects on cardiac performance of adult Wistar rat ventricles were studied with a novel approach applying a microcalorimetric technique. Resting heat (Hr) was significantly decreased by Ch antibodies (DeltaHrCh = 4.8 +/- 0.9 mW/g). Although the Hr decrease can be associated with diminished activity of the Na+/K+ pump, the magnitude of the effect (25% of control Hr) indicates that additional processes may also be affected. Ch antibodies induced an initial increase in developed pressure (P), which was associated with a decreased contractile economy. However, after 30 min of Ch antibody perfusion, P reached a significantly lower level (DeltaPCh = 3.8 +/- 1.2 mN/mm2) without changes in active heat per beat (Ha'). Consequently, Ha'/P ratio increased, indicating that the energetic cost per unit of P was higher. In contrast, P and Ha' were both significantly and reversibly decreased by NCh antibodies (DeltaPNCh = 4.4 +/- 1.2 mN/mm2; DeltaHa'NCh = 9.7 +/- 2.2 mJ/g), but Ha'/P remained unaffected. According to these data, normal hearts exposed to Ch antibodies present a biphasic mechanical response: 1) an initial period of increased contractility (and decreased global muscle economy) consistent with antibodies with beta1-adrenergic activity, such as those used in the present study, and 2) a decrease in P at 30 min of Ch antibody perfusion, which suggests that another Ca(2+)-related mechanism is compromised. These data contribute to redefine the role of antibody-mediated responses in the pathophysiology of chronic chagasic cardiomyopathy as agents of myocardial failure.

Risk progression to chronic Chagas cardiomyopathy: influence of male sex and of parasitaemia detected by polymerase chain reaction

BACKGROUND

Polymerase chain reaction (PCR) allows detection of Trypanosoma cruzi in blood throughout the course of Chagas' disease.

OBJECTIVE

To determine whether T cruzi DNA detected by PCR is associated with progression to chronic Chagas cardiomyopathy.

DESIGN

Prospective cohort study.

SETTING

A tertiary care centre in Argentina.

PATIENTS

56 consecutive patients with chronic T cruzi infection.

METHODS

Clinical examination, ECG, and Doppler echocardiography were carried out at baseline and at the end of the follow up. Detection of T cruzi DNA by PCR amplifying a nuclear sequence was undertaken in all patients at baseline.

MAIN OUTCOME MEASURES

Progression was defined as death from chronic cardiomyopathy or the presence of a new ECG or left ventricular echocardiographic abnormality at the end of follow up.

RESULTS

The 56 patients (21 male, 35 female; mean (SD) age, 56.0 (11.3) years) were followed for a mean 936.3 (244.39) days. Progression to cardiomyopathy was detected in 12 patients (21.4%). Three of these patients died after baseline evaluation. Univariate analysis showed that a positive PCR (relative risk 4.09, 95% confidence interval (CI) 1.60 to 9.85) and male sex (5.00, 95% CI 1.65 to 15.73) were associated with progression. Multivariable logistic regression indicated that both sex and PCR were independent variables affecting the outcome.

CONCLUSIONS

In a cohort of seropositive individuals, patients with T cruzi DNA detected by PCR and male patients were at higher risk of progression. These results highlight the importance of T cruzi in the pathophysiology of chronic cardiomyopathy.