Randomized trial of benznidazole for chronic Chagas' cardiomyopathy

BACKGROUND:The role of trypanocidal therapy in patients with established Chagas' cardiomyopathy is unproven.METHODS:We conducted a prospective, multicenter, randomized study involving 2854 patients with Chagas' cardiomyopathy who received benznidazole or placebo for up to 80 days and were followed for a mean of 5.4 years. The primary outcome in the time-to-event analysis was the first event of any of the components of the composite outcome of death, resuscitated cardiac arrest, sustained ventricular tachycardia, insertion of a pacemaker or implantable cardioverter-defibrillator, cardiac transplantation, new heart failure, stroke, or other thromboembolic event.RESULTS:The primary outcome occurred in 394 patients (27.5%) in the benznidazole group and in 414 (29.1%) in the placebo group (hazard ratio, 0.93; 95% confidence interval [CI], 0.81 to 1.07; P=0.31). At baseline, a polymerase-chain-reaction (PCR) assay was performed on blood samples obtained from 1896 patients; 60.5% had positive results for Trypanosoma cruzi on PCR. The rates of conversion to negative PCR results (PCR conversion) were 66.2% in the benznidazole group and 33.5% in the placebo group at the end of treatment, 55.4% and 35.3%, respectively, at 2 years, and 46.7% and 33.1%, respectively, at 5 years or more (P<0.001 for all comparisons)...

Autoantibodies to neurotrophic receptors TrkA, TrkB and TrkC in patients with acute Chagas' disease.

Neurotrophic receptors TrkA and TrkC double up as receptors that Trypanosoma cruzi uses to invade cells and as autoantigen in T. cruzi-infected individuals (with Chagas' disease). Consequently, autoantibodies against TrkA and TrkC (ATA) potently block T. cruzi invasion in vitro and in ATA-immunized mice. Thus, ATA could keep T. cruzi invasion in check in Chagas' disease. However, ATA has been examined only in patients with chronic Chagas' disease. To determine whether ATA potentially participate in the early stage of infection, we analysed the sera of 15 patients with acute Chagas' disease, 4-66 years of age. We find that all sera contain high antibody titres to TrkA, TrkB and TrkC, but not to other growth factor receptors, indicating that ATA are produced relatively soon after T. cruzi infection by an age-independent process. One individual, who acquired the disease after an accidental laboratory infection, converted to Trk-antibody (Ab)-seronegative when progressing to the chronic phase. ATA from acute patients were of low avidity (K(0) <24.8 x 10(-8) m) and of IgM and IgA isotypes. In contrast, ATA from chronic patients were of high avidity (K(o) = 1.4 to 4.5 x 10(-8) m) and of the IgG2 isotype. Therefore, ATA underwent affinity maturation and class switch when patients progressed from acute to chronic disease. Thus, it may be that Trk autoimmunity, which starts in the acute Chagas' disease, plays a role in attenuating parasitemia and tissue parasitism that characterizes the acute/chronic phase transition of Chagas' disease.

Challenges and opportunities for primary, secondary, and tertiary prevention of Chagas' disease.

A century after its discovery, Chagas' disease still represents a major public health challenge in Latin America. Moreover, because of growing population movements, an increasing number of cases of imported Chagas' disease have now been detected in non-endemic areas, such as North America and some European countries. This parasitic zoonosis, caused by Trypanosoma cruzi, is transmitted to humans by infected Triatominae insects, or occasionally by non-vectorial mechanisms, such as blood transfusion, mother to fetus, or oral ingestion of materials contaminated with parasites. Following the acute phase of the infection, untreated individuals enter a chronic phase that is initially asymptomatic or clinically unapparent. Usually, a few decades later, 40-50% of patients develop progressive cardiomyopathy and/or motility disturbances of the oesophagus and colon. In the last decades several interventions targeting primary, secondary and tertiary prevention of Chagas' disease have been attempted. While control of both vectorial and blood transfusion transmission of T cruzi (primary prevention) has been successful in many regions of Latin America, early detection and aetiological treatment of asymptomatic subjects with Chagas' disease (secondary prevention) have been largely underutilised. At the same time, in patients with established chronic disease, several pharmacological and non-pharmacological interventions are currently available and have been increasingly used with the intention of preventing or delaying complications of the disease (tertiary prevention). In this review we discuss in detail each of these issues.

Transmisión congénita del Trypanosoma cruzi en Brasil: estimativa de prevalencia baseada en resultados preliminares de la encuesta nacional serológica en niños menores de cinco años, así como otras fuentes / Congenital transmission of Trypanosoma cruzi in Brazil: estimation of prevalence based on preliminary data of national serological surveys in children under 5 years old and other sources

A prevalence estimation of congenital transmission in Brazil is performed, based on several sources of recent data. From a serological survey conducted now in Brazil, with children below 5 years old, preliminary data from the state of Minas Gerais only 19/9,556 children did have antibodies against Trypanosoma cruzi. All 19 mothers were infected, but only one child persisted with antibodies on a second blood collection, hence diagnosed as congenital. The other were just passive transference of maternal antibodies. From a recent publication, 278 children born from 145 infected mothers were studied. Two cases (0.7%) were congenital. In other source, from 1,348 blood donors, 35 were born in non endemic areas. When 10 of them were called, 8 were born from infected mothers and five may be congenital. Finally, no infection was detected in 93 children born from 78 infected mothers. The reasons for this low prevalence are discussed, are lower than in other countries of the South Cone, that harbor also T. cruzi 2, but are unrecognized up to now.

Blood culture and polymerase chain reaction for the diagnosis of the chronic phase of human infection with Trypanosoma cruzi.

In the present study, we evaluated for the first time the profile of blood parasitism in untreated, chronic Chagas' disease. The study was conducted on 60 patients and a control group of nine serologically negative individuals. Analysis of three blood samples showed 70% cumulative positivity for blood culture and 86.7% positivity for PCR. The comparison of the two tests revealed that 41.1% (74/180) of the samples presented positive results for both PCR and blood culture, 22.2% (40/180) were positive for PCR alone, and 4.4% (8/180) were positive for blood culture and negative for PCR. The addition of the second sample raised positivity significantly for both blood culture ( P=0.0000) and PCR ( P=0.0369). Addition of the third sample was also statistically significant for blood culture ( P=0.0001) but not for PCR ( P=0.1186). These data point to the importance of studying the parasitemia of Trypanosoma cruzi-infected individuals before specific treatment. They also suggest that at least two blood samples should be collected and that two tests should be used, if possible--a procedure that considerably improves the parasitologic diagnosis of Chagas' disease and the evaluation of therapeutic efficacy.

Chagas' heart disease.

Chagas' disease is caused by a protozoan parasite, Trypanosoma cruzi, that is transmitted to humans through the feces of infected bloodsucking insects in endemic areas of Latin America, or occasionally by nonvectorial mechanisms, such as blood transfusion. Cardiac involvement, which typically appears decades after the initial infection, may result in cardiac arrhythmias, ventricular aneurysm, congestive heart failure, thromboembolism, and sudden cardiac death. Between 16 and 18 million persons are infected in Latin America. The migration of infected Latin Americans to the United States or other countries where the disease is uncommon poses two problems: the misdiagnosis or undiagnosis of Chagas' heart disease in these immigrants and the possibility of transmission of Chagas' disease through blood transfusions. Diagnosis is based on positive serologic tests and the clinical features. The antiparasitic drug, benznidazole, is effective when given for the initial infection and may also be beneficial for the chronic phase. The use of amiodarone, angiotensin-converting enzyme inhibitors, and pacemaker implantation may contribute to a better survival in selected patients with cardiac involvement of chronic Chagas' disease.

[Specific treatment attempt, with ticlopidine, of patients with Chagas disease chronic phase]. / Tentativa de tratamento específico, por meio da ticlopidina, de pacientes com doença de Chagas em fase crônica.

In a previous study, ticlopidine decreased the parasitemia and mortality of mice infected by Trypanosoma cruzi. Therefore, this drug was administered to 12 patients with Chagas' disease, in the chronic phase. For 90 days, 150, 200 or 250 mg were utilized according to whether the recipients were children, adolescents or adults, respectively. A fully unsuccessful outcome was documented, both serologically as well as parasitologically.

[Protective effect of benznidazole against parasite reactivation in patients chronically infected with Trypanosoma cruzi and treated with corticoids for associated diseases]. / Efeito protetor do benznidazol contra a reativação parasitária em pacientes cronicamente infectados pelo Trypanosoma cruzi e tratados com corticóide em virtude de afecções associadas.

Patients in the chronic phase of Chagas' disease and receiving corticoid because of concommitant diseases were treated with benznidazole, which was initiated at the same time of the use of corticoid in a group of 12 patients or 15 days afterwards in 6 patients. It has been proved in another paper that in the chronic phase of Chagas' disease corticoid use is associated with increased parasitemia, as evaluated by xenodiagnosis. In this study benznidazole use prevented this increase, and we suggest that in immunocompromised patients with chronic Chagas' disease the use of this drug could be useful.

[Nifurtimox as a prophylactic drug to prevent reactivation in chronic chagasic patients treated with corticoid for associated diseases]. / Efeito protetor do nifurtimox contra a reativação parasitária em pacientes cronicamente infectados pelo Trypanosoma cruzi e tratados com corticoide em virtude de afecções associadas.

Patients in the chronic phase of Chagas' disease and receiving corticoid because of concommitant diseases were treated with nifurtimox. We proved in another paper that in the chronic phase of Chagas' disease corticoid use is associated with increased parasitemia, as evaluated by xenodiagnosis. In this study nifurtimox use prevented this increase, and we suggest that in immunocompromised patients with chronic Chagas' disease the use of this drug could be useful.

Efeito protetor do nifurtimox contra a reativação parasitária em pacientes cronicamente infectados pelo Trypanosoma cruzi e tratados com corticoide em virtude de afecçoes associadas / Nifurtimox as a prophylactic drug to prevent reactivation in chronic chagasic patients treated with corticoid for associated diseases

Pacientes na fase crônica da doença de Chagas foram tratados com corticóide em virtude de afecções associadas e, a fim de tentar coibir reativação da infecção pelo Trypanosoma cruzi, houve uso concomitante do nifurtimox. Levando em conta o verificado em pesquisa anterior, quando corticóide de fato promoveu aumento da parasitemia detectada pelo xenodiagnóstico, pôde ser notado que o nifurtimox mostrou-se apto a evitar a citada acentuação parasitária, podendo tal constatação ser útil em procedimentos assistenciais, quando circunstancialmente estiverem presentes doença de Chagas e imunodepressão.

Patients in the chronic phase of Chagas' disease and receiving corticoid because of concommitant diseases were treated with nifurtimox. We proved in another paper that in the chronic phase of Chagas' disease corticoid use is associated with increased parasitemia, as evaluated by xenodiagnosis. In this study nifurtimox use prevented this increase, and we suggest that in immunocompromised patients with chronic Chagas' disease the use of this drug could be useful.

Diagnostic electrocardiography in epidemiological studies of Chagas' disease: multicenter evaluation of a standardized method.

An electrocardiographic recording method with an associated reading guide, designed for epidemiological studies on Chagas' disease, was tested to assess its diagnostic reproducibility. Six cardiologists from five countries each read 100 electrocardiographic (ECG) tracings, including 30 from chronic chagasic patients, then reread them after an interval of 6 months. The readings were blind, with the tracings numbered randomly for the first reading and renumbered randomly for the second reading. The physicians, all experienced in interpreting ECGs from chagasic patients, followed printed instructions for reading the tracings. Reproducibility of the readings was evaluated using the kappa (kappa) index for concordance. The results showed a high degree of interobserver concordance with respect to the diagnosis of normal vs. abnormal tracings (kappa = 0.66; SE 0.02). While the interpretations of some categories of ECG abnormalities were highly reproducible, others, especially those having a low prevalence, showed lower levels of concordance. Intraobserver concordance was uniformly higher than interobserver concordance. The findings of this study justify the use by specialists of the recording of readings method proposed for epidemiological studies on Chagas' disease, but warrant caution in the interpretation of some categories of electrocardiographic alterations.

Long-lasting antibodies detected by a trans-sialidase inhibition assay of sera from parasite-free, serologically cured chagasic patients.

A test based on the inhibition by antibodies of the trans-sialidase was used to analyze infection by Trypanosoma cruzi, the agent of Chagas' disease. Sera collected during the longitudinal follow-up of benznidazole-treated acutely and congenitally infected patients became negative for T. cruzi as determined by tests presently used to assess cure; however, the sera remained positive for T. cruzi by the trans-sialidase inhibition assay (TIA) up to 14 years after treatment. Therefore, TIA is a highly sensitive marker for previous T. cruzi infection.

[The influence of corticoids, in Chronic Chagas disease, administered in virtue of associated disorders]. / Influência de corticóide, na doença de Chagas crônica, administrado em virtude de afecções associdas.

Patients with chronic Chagas' disease and simultaneous medical problems treated with corticosteroid were studied in order to evaluate steroid influence on chronic Trypanosoma cruzi infection. Parasitological assessment, radiological and electrocardiographic studies as well as non specific tests were performed in patients and in a control group that included chronic infected patients not treated with steroid. Xenodiagnosis showed a clear increase in T. cruzi parasitemia, related to the corticosteroid dosage, without clinical manifestations during the study follow-up period.

Trypanosoma cruzi stocks isolated from acute Chagas disease patients lead to lethal murine infection.

Ten Trypanosoma cruzi stocks recently isolated from patients in acute and chronic phases of Chagas disease were inoculated to susceptible (A/Sn) mice. The mice were inoculated with 10(4) trypomastigotes intraperitoneally and monitored for parasitaemia and mortality for up to 300 d. The results demonstrated that (i) T. cruzi stocks isolated from patients in the acute phase killed animals, while stocks from patients in the chronic phase did not; (ii) survival curves differed statistically among mice infected with lethal stocks, and (iii) parasite burden did not affect the mortality rate of mice.

[Brazilian multicenter study of sotalol effectiveness in ventricular arrhythmias]. / Estudo multicêntrico Brasileiro da eficácia do sotalol em arritmias ventriculares.

PURPOSE: To evaluate the effects of sotalol in patients with nonsustained ventricular tachyarrhythmia (NSVT). METHODS: Ninety patients were enrolled. Patients were submitted to a double-blind crossover randomized study (placebo x 320 ms/po/d/sotalol; 4 weeks, after a wash-out control period. Holter recordings were performed in control (Ct), placebo (Pb) and drug (Dg) periods. Eligible patients had > 50/h isolated ventricular premature beats (VPB), in control, with or without pairs (P) or nonsustained VT (NSVT; > 3 beats, > 100bpm). Drug efficacy criteria were; > or = 75% reduction in isolated VPB, reduction > or = 90% of P and NSVT. The effects of the Dg were evaluated in the global population, in patients with Chagas' disease, idiopathic arrhythmias and ischemic/hypertensive patients. RESULTS: Differences between control and placebo were NS. Isolated VPB; Dg was effective in 42% (38/90 patients) with a mean of Pb and Dg respectively of 11,770 +/- 13,818 and 1,043 +/- 1,554 (p < 0.001). Pairs: drug was effective in 48% (32/67 patients) with a mean of Pb and Dg respectively of 439 +/- 586 and 27 +/- 52 (p < 0.001). NSVT: drug effectiveness was 53% (19/36 patients) with a mean of Pb and Dg respectively of 445 +/- 1,148 and 2.5 +/- 5.8 (p < 0.102). In patients with Chagas' disease, the reduction in VPB was 33% (13/39 patients), in pairs was 42+ (14/34) and in NSVT was 64% (12/22). In idiopathic patients the reduction of VPB was 53% (17/32 patients), in pairs was 50% (10/20) and in NSVT was 36% (4/11). In ischemic and hypertensive patients the reduction of VPB was 47% (7/15 patients) and 73% in pairs (8/11). CONCLUSION: In the present study, sotalol was effective in the control of nonsustained ventricular tachyarrhythmia, with minimal side-effects.

Estudo multicêntrico brasileiro da eficácia do sotalol em arritmias ventriculares / Brazilion Multicenter Study of Sotalol Effectiveness in Ventricular Arrhythmias

Objetivo - Avaliar através de ensaio clínico prospectivo, randomizado, duplo-cego cruzado contra placebo, a eficácia do sotalol na dose oral de 320 miligramas diários em reduzir taquiarritmias ventriculares näo sustentadas (TVNS). Métodos - Foram avaliados em condiçöes de controle (Ct), placebo (Pb) e droga (Dg), 90 portadores de um número médio maior ou igual a 50 extra-sístole horárias (EV), com ou sem respostas pareadas (RP) e TVNS, registradas no Holter. Considerou-se a droga como efetiva, fren a uma reduçäo maior ou igual a 75 por cento das EV e maior ou igual a 90 por cento das RP e TVNS. Avaliaram-se os resultados globais e os observados em doenças específicas, incluindo a cardiopatia chagásica crônica, arritmias ventriculares idiopáticas e doença coronariana e hipertensiva sistêmica. Resultados - Näo ocorreram diferenças significativas entre Ct e Pb. Globalmente, a droga reduziu as EV em 42 por cento (38/90 pacientes), as RP em 48 por cento (32/67 e as TVNS em 53 por cento (19/36), com méis respectivas entre Pb e Dg de 11.770 mais ou menos 13.818 para 1.043 mais ou menos 1.554 nas EV (p menor a 0,001); de 439 mais ou menos 586 para 27 mais ou menos 52 nas RP (p menor a 0,001) e de 445 mais ou menos 1.147 para 2,5 mais ou menos 5,8 nas TVNS (p menor a 0,102). Nos chagásicos, reduçäo das EV de 33 por cento (13/39 pacientes), das RP em 42 por cento (14/34) e das TVNS em 64 por cento (12/22). Nos indiopáticos, a reduçäo das EV foi de 53 por cento (17/32 pacientes), das RP de 50 por cento (0/0) e das TVNS de 36 por cento (4/11). Nos isquêmicos e/ou hipertensos, a reduçào das EV foi de 47 por cento (7/15 pacientes) e de 73 por cento nas RP (8/11). Conclusäo - Na populaçäo estudada e na dose indicada, o sotalol mostrou ser um fármaco efetivo para controle de TVNS, apresentando mínimos efeitos colaterais.

[A comparative study between natural and artificial xenodiagnosis in chronic Chagas' disease patients]. / Estudo comparativo entre o xenodiagnóstico natural e o artificial, em chagásicos crônicos.

In order to study the sensitivity of the xenodiagnosis technique a comparison between natural and artificial xenodiagnosis methods was performed in 57 chronic phase chagasic patients (31 female), with ages ranging from 26 to 83 years. All patients had demonstrable antibodies against Trypanosoma cruzi. Forty first instar nymphs of Dipetalogaster maximus were used for each of both methods and for each patient. The positivity of xenodiagnosis artificial was significantly higher than the routine test method. These results did show that a single application of 40 bugs by the artificial method yielded a similar result than 3 applications of 40 bugs each, by the natural method. The positivity of xenodiagnosis was significantly higher in patients between 56-65 and 66-83 years old than at other ages. Males were predominant in this age group. These results showed the viability of artificial xenodiagnosis and its use in routine laboratory testing.