Carlos Vigliano

Side effects of benznidazole as treatment in chronic Chagas disease: fears and realities

Chagas disease is caused by a parasite, Trypanosoma cruzi, transmitted primarily by a triatomine insect and affects approximately 8 million people in Latin American countries. The principal aim of the management of the disease is to avoid the development of cardiomyopathy and transmission by blood transfusion, congenital and organ transplants. Currently, benznidazole is the only etiological treatment commercially available for the disease until new and better drugs can be developed and tested. Benznidazole has been used even though it does not have all the conditions of an ideal drug. The efficacy and tolerance of benznidazole is inversely related to the age of the patient, while its side effects are more frequent in elderly patients. The side effects are systematically evaluated only in controlled studies designed for that purpose. However, the true clinical impact of the side effects could be different, considering that the treatment is for a short duration (between 30 and 60 days) and only carried out once. In this article, we discuss the benefits and risks of the treatment with benznidazole from a clinical point of view to be considered for the management of the treatment of chronic adult Chagas disease patients in the current medical practice.

Molecular identification of Trypanosoma cruzi discrete typing units in end-stage chronic Chagas heart disease and reactivation after heart transplantation.

BACKGROUND One hundred years after the discovery of Chagas disease, it remains a major neglected tropical disease. Chronic Chagas heart disease (cChHD) is the most severe manifestation. Heart transplantation is the proper treatment for end-stage heart failure, although reactivation of disease may result after receipt of immunosuppressive therapy. T. cruzi strains cluster into 6 discrete typing units (DTUs; I-VI) associated with different geographical distribution, transmission cycles and varying disease symptoms. In the southern cone of South America, T. cruzi II, V, and VI populations appear to be associated with Chagas disease and T. cruzi I with sylvatic cycles. METHODS Molecular characterization of DTUs, T. cruzi I genotypes (on the basis of spliced-leader gene polymorphisms), and minicircle signatures was conducted using cardiac explant specimens and blood samples obtained from a cohort of 16 Argentinean patients with cChHD who underwent heart transplantation and from lesion samples obtained from 6 of these patients who presented with clinical reactivation of Chagas disease. RESULTS Parasite persistence was associated with myocarditis progression, revealing T. cruzi I (genotype Id) in 3 explant samples and T. cruzi II, V, or VI in 5 explant samples. Post-heart transplantation follow-up examination of bloodstream DTUs identified T. cruzi I in 5 patients (genotypes Ia or Id) and T. cruzi II, V, or VI in 7 patients. T. cruzi I, V, and VI were detected in skin chagoma specimens, and T. cruzi V and VI were detected in samples obtained from patients with myocarditis reactivations. Multiple DTUs or genotypes at diverse body sites and polymorphic minicircle signatures at different cardiac regions revealed parasite histotropism. T. cruzi I infections clustered in northern Argentina (latitude, 23 degrees S-27 degrees S), whereas T. cruzi II, V, or VI DTUs were more ubiquitous. CONCLUSIONS Multiple DTUs coexist in patients with Chagas disease. The frequent finding of T. cruzi I associated with cardiac damage was astounding, revealing its pathogenic role in cChHD at the southern cone.

Usefulness of PCR Strategies For Early Diagnosis of Chagas' Disease Reactivation and Treatment Follow-Up in Heart Transplantation

Heart transplantation (HTx) is a useful therapy for end‐stage Chagaś cardiomyopathy; however, Chagas reactivation remains a mayor complication. Parasitological methods offer poor diagnostic sensitivity, and use of more sensitive tools such as the Polymerase chain reaction (PCR) is usually necessary. In the present study, reactivation incidence and PCR usefulness for early reactivation diagnosis, as well as for treatment response evaluation during follow‐up, were analyzed using Strout parasite detection test, in 10 of 222 consecutive HTx patients suffering Chagas cardiomyopathy. PCR strategies targeted to minicircle sequences (kDNA, detection limit 1 parasite/ 10 mL blood) and miniexon genes (SL‐DNA, 200 parasite/10 mL) were performed to compare parasite burdens between samples. No patients received prophylactic antiprotozoal therapy (benznidazole). Five patients (50%) exhibited clinical reactivation within a mean period of 71.6 days; positive Strout results were observed in most cases presenting clinical manifestations. kDNA‐PCR was positive 38–85 days before reactivation, whereas SLDNA‐PCR became positive only 7–21 days later, revealing post‐HTx parasitic load enhancement present prior to clinical reactivation development. Reactivations were successfully treated with benznidazole and generated negative PCR results. Results observed in this study indicate the value of PCR testing for an early diagnosis of Chagas reactivation as well as for monitoring treatment efficacy.

Value of echocardiography for diagnosis and prognosis of chronic Chagas disease cardiomyopathy without heart failure

Objectives: To establish the usefulness of echocardiography for the clinical classification of patients with Chagas disease and to determine the predictors of mortality and clinical events. Methods: 849 patients with chronic Chagas disease with a mean follow up of 9.9 years were studied. On admission, ECG, chest radiograph, and two dimensional echocardiogram were obtained from all patients. Clinical events were defined as new ECG abnormalities, change in clinical status resulting in transfer to another group, and death. Morphologically characterised segmental lesions were also seen in 12 patients on a second harmonic echocardiogram with intravenous contrast agent. Univariate and multivariate analysis for clinical events and mortality were performed. Setting: Community of San Martín, Buenos Aires, Argentina. Results: Change in clinical group (68 of 833 survivors v 15 of 16 who died, p < 0.001), left ventricular systolic dimension (mean (SD) 3.06 (0.72) cm v 4.71 (0.90) cm, p < 0.0001), and ejection fraction (mean (SD) 0.67 (0.11)% v 0.42 (0.17)%, p < 0.0001) were found to be the only predictors of mortality. ECG abnormalities related to the disease (in 220 of 699 patients with no clinical event v 98 of 150 patients with a clinical event, p < 0.0001), left ventricular diastolic dimension (mean (SD) 4.88 (0.54) cm v 5.44 (0.83) cm, p < 0.0001), left ventricular systolic dimension (mean (SD) 2.98 (0.62) cm v 3.64 (1.03) cm, p < 0.0001), and ejection fraction (mean (SD) 0.68 (0.10)% v 0.60 (0.16)%, p < 0.0001) were predictors of clinical events. Segmental lesions were observed in 211 of 849 patients (25%). Segmental lesions were seen in 66 (13%) and systolic dysfunction was seen in four of 505 (0.8%) patients with normal ECG. Significant differences were found between the groups of patients (group 0: reactive serology and normal ECG and chest radiography without cardiac enlargement and no signs of heart failure; group 1: reactive serology and abnormal ECG and chest radiography without cardiac enlargement; group 2: reactive serology and abnormal ECG and chest radiography with cardiac enlargement and no signs of heart failure). Conclusion: Echocardiography was useful both to characterise and to determine the prognosis of patients with chronic Chagas disease without heart failure.

Etiological treatment of chronic Chagas disease: neglected ‘evidence’ by evidence-based medicine

No randomized clinical trials regarding the etiological treatment of chronic Chagas disease can be found in the medical literature. However, other ‘evidence’ sustaining the use of anti-Trypanosoma cruzi drugs for adult individuals with Chagas disease will be analyzed along with the limitations in evaluating the treatment efficacy. Today, the hypothesis of T. cruzi persistence in the target organs giving rise to the chronic inflammatory response is sustained. In addition, several experimental, pathological, nonrandomized clinical studies and studies based on the response or serological evolution (besides the clinical experience) demonstrate the role of T. cruzi in the pathogenesis of the chronic stage and the efficacy of etiological treatment to reduce the titers of antibodies and the progression of chronic Chagas heart disease. All of this supports the recommendation of treatment for every patient diagnosed with Chagas disease. The interpretation of this sum of evidence is not considered from the perspective of evidence-based medicine.

Impact of Aetiological Treatment on Conventional and Multiplex Serology in Chronic Chagas Disease

Background The main criterion for treatment effectiveness in Chagas Disease has been the seronegative conversion, achieved many years post-treatment. One of the main limitations in evaluating treatment for chronic Chagas disease is the lack of reliable tests to ensure parasite clearance and to examine the effects of treatment. However, declines in conventional serological titers and a new multiplex assay can be useful tools to monitor early the treatment impact. Methodology/Principal Findings Changes in antibody levels, including seronegative conversion as well as declines in titers, were serially measured in 53 benznidazole-treated and 89 untreated chronic patients in Buenos Aires, Argentina with a median follow-up of 36 months. Decrease of titers (34/53 [64%] treated vs. 19/89 [21%] untreated, p<0.001) and seronegative conversion (21/53, [40%] treated vs. 6/89, [7%] untreated, p<0.001) in at least one conventional serological test were significantly higher in the benznidazole-treated group compare with the untreated group. When not only complete seronegative conversion but also seronegative conversion on 2 tests and the decreases of titers on 2 or 3 tests were considered, the impact of treatment on conventional serology increased from 21% (11/53 subjects) to 45% (24/53 subjects). A strong concordance was found between the combination of conventional serologic tests and multiplex assay (kappa index 0.60) to detect a decrease in antibody levels pos-treatment. Conclusions/Significance Treatment with benznidazole in subjects with chronic Chagas disease has a major impact on the serology specific for T. cruzi infection in a shorter follow-up period than previously considered, reflected either by a complete or partial seronegative conversion or by a significant decrease in the levels of T. cruzi antibodies, consistent with a possible elimination or reduction of parasite load.

Indicadores clínicos de progresión de la miocarditis chagásica crónica

Introduccion y objetivos. Los estudios de pronostico efectuados sobre la mortalidad de la cardiopatia se han centrado en la etapa final de la enfermedad (insuficiencia cardiaca). Nuestro objetivo fue establecer los indicadores de progresion de la enfermedad de Chagas en estadios tempranos. Material y metodo. Se incluyo a 856 pacientes con 3 pruebas reactivas anti-Trypanosoma cruzi y se excluyo a los pacientes con insuficiencia cardiaca. Se utilizo la siguiente estratificacion clinica: grupo I, sin cardiopatia; grupo II, con cardiopatia y sin dilatacion del ventriculo izquierdo (VI); grupo III, con dilatacion del VI, sin insuficiencia cardiaca. El punto final de evaluacion fue la progresion hacia un grupo clinico de mayor severidad o la muerte cardiovascular. Se incluyeron las variables clinicas, electrocardiograficas y ecocardiograficas en un analisis multivariado (Cox) y se construyo una puntuacion de riesgo. Resultados. La edad promedio fue de 43,7 anos y el seguimiento de 8 anos. La edad (hazard ratio [HR] = 1,05; intervalo de confianza [IC] del 95%, 1,02-1,07; p < 0,001), el diametro sistolico del VI (HR = 1,06; IC del 95%, 1,04-1,09; p < 0,001), los trastornos de conduccion intraventricular (HR = 1,85; IC del 95%, 1,02-3,36; p = 0,04) y la taquicardia ventricular sostenida (HR = 3,97; IC del 95%, 1,65-9,58; p = 0,002) fueron predictores de progresion de la cardiopatia. El tratamiento con benznidazol redujo el riesgo de progresion (HR = 0,40; IC del 95%, 0,23-0,72; p = 0,002). La puntuacion de riesgo construido estratifico adecuadamente la probabilidad de progresion de la cardiopatia. Conclusiones. Los indicadores clinicos y la puntuacion propuesta pueden establecer el pronostico de progresion de la miocarditis chagasica cronica sin insuficiencia cardiaca.

Cardiomyocyte hypertrophy, oncosis, and autophagic vacuolization predict mortality in idiopathic dilated cardiomyopathy with advanced heart failure.

OBJECTIVES The aim of this study was to identify the remodeling parameters cardiomyocyte (CM) damage or death, hypertrophy, and fibrosis that may be linked to outcomes in patients with advanced heart failure (HF) in an effort to understand the pathogenic mechanisms of HF that may support newer therapeutic modalities. BACKGROUND There are controversial results on the influence of fibrosis, CM hypertrophy, and apoptosis on outcomes in patients with HF; other modalities of cell damage have been poorly investigated. METHODS In endomyocardial biopsy specimens from 100 patients with idiopathic dilated cardiomyopathy and advanced HF, CM diameter and the extent of fibrosis were determined by morphometry. The proportion of CMs with evidence of apoptosis, autophagic vacuolization (AuV), and oncosis was investigated by immunohistochemical methods and by terminal deoxynucleotidyl transferase-mediated deoxyuridine triphosphate nick end labeling. Those parameters were correlated with mortality in 3 years of follow-up by univariate analysis and with multivariate models incorporating the clinical variables more relevant to the prediction of outcomes. RESULTS CM AuV occurred in 28 patients (0.013 ± 0.012%) and oncosis in 41 (0.109 ± 0.139%). Nineteen patients showed both markers. Apoptotic CM nuclei were observed in 3 patients. In univariate analysis, CM diameter and AuV, either alone or associated with oncosis, were predictors of mortality. In multivariate analysis, CM diameter (hazard ratio: 1.37; 95% confidence interval: 1.12 to 1.68; p = 0.002) and simultaneous presence in the same endomyocardial biopsy specimen of AuV and oncosis (hazard ratio: 2.82; 95% confidence interval: 1.12 to 7.13; p = 0.028) were independent predictors of mortality. CONCLUSIONS CM hypertrophy and AuV, especially in association with oncosis, are predictors of outcome in patients with idiopathic dilated cardiomyopathy and severe HF.

Inhibitory Receptors Are Expressed by Trypanosoma cruzi-Specific Effector T Cells and in Hearts of Subjects with Chronic Chagas Disease

We had formerly demonstrated that subjects chronically infected with Trypanosoma cruzi show impaired T cell responses closely linked with a process of T cell exhaustion. Recently, the expression of several inhibitory receptors has been associated with T cell dysfunction and exhaustion. In this study, we have examined the expression of the cytotoxic T lymphocyte antigen 4 (CTLA-4) and the leukocyte immunoglobulin like receptor 1 (LIR-1) by peripheral T. cruzi antigen-responsive IFN-gamma (IFN-γ)-producing and total T cells from chronically T. cruzi-infected subjects with different clinical forms of the disease. CTAL-4 expression was also evaluated in heart tissue sections from subjects with severe myocarditis. The majority of IFN-γ-producing CD4+ T cells responsive to a parasite lysate preparation were found to express CTLA-4 but considerably lower frequencies express LIR-1, irrespective of the clinical status of the donor. Conversely, few IFN-γ-producing T cells responsive to tetanus and diphtheria toxoids expressed CTLA-4 and LIR-1. Polyclonal stimulation with anti-CD3 antibodies induced higher frequencies of CD4+CTAL-4+ T cells in patients with severe heart disease than in asymptomatic subjects. Ligation of CTLA-4 and LIR-1 with their agonistic antibodies, in vitro, reduces IFN-γ production. Conversely, CTLA-4 blockade did not improved IFN-γ production in response to T. cruzi antigens. Subjects with chronic T. cruzi infection had increased numbers of CD4+LIR-1+ among total peripheral blood mononuclear cells, relative to uninfected individuals and these numbers decreased after treatment with benznidazole. CTLA-4 was also expressed by CD3+ T lymphocytes infiltrating heart tissues from chronically infected subjects with severe myocarditis. These findings support the conclusion that persistent infection with T. cruzi leads to the upregulation of inhibitory receptors which could alter parasite specific T cell responses in the chronic phase of Chagas disease.

Mixomas cardíacos: correlaciÓn anatomoclínica

Introduction and objectives. Myxomas are the most common type of primary cardiac tumors. The aim of this study was to analyze the clinical forms of presentation of cardiac myxoma, the postoperative evolution, and the possibility of recurrence and tumoral embolism. Patients and method. From July 1992 to March 1999, 31 patients with myxoma were studied. Cell cycles (ploidy pattern of the tumoral DNA) were studied in 12 patients to evaluate the risk of recurrence and tumoral embolism. Results. The most frequent clinical manifestations were constitutional symptoms (74%), dyspnea (45%), and embolism (41%). Smaller-diameter myxomas correlated independently with tumoral embolism (45%). The inhospital mortality was 3.2%, no deaths were observed during follow-up (mean: 4.8 years). No patients had clinical or echocardiographic signs of tumoral recurrence. Patients with tumoral embolism (n = 8) were compared with patients without embolism (n = 4). Patients who suffered embolism had higher S phase > 7 and/or DNA index > 1.2 (4/4 patients [100%], p= 0.061) than patients without embolism (2/8 patients [25%]). Cytometry of the only recurrent tumor (second operation) revealed a diploid tumor with a significantly more frequent S phase (10%) than in sporadic myxomas (4.27 ± 2.32%, p = 0.039). Conclusions. Constitutional symptoms, dyspnea, and tumor embolism were the most frequent clinical manifestations. Clinical and anatomopathologic characteristics and the cell cycle were not significantly related to tumoral embolism, but there was a tendency toward a higher proportion of cells in S phase and a higher DNA index in tumors associated with embolism. The S phase was significantly more frequent in the only case of recurrent myxoma and could be a potential marker of recurrence.