Reinfections with strains of Trypanosoma cruzi, of different biodemes as a factor of aggravation of myocarditis and myositis in mice

Abstract

Reinfections with Trypanosoma cruzi in patients from endemic areas have been claimed to be an aggravation factor of cardiac manifestations in Chagas' disease. In the present study, the influence of triple infections with strains of different biodemes, on cardiac and skeletal muscle lesions was experimentally tested. Fifty eight mice chronically infected with the Colombian strain (Biodeme Type III) were successively reinfected as follows: 1 st group -reinfected with 21 SF strain (Type II) followed by Y strain (Type I ); 2 nd group -reinfections with Y strain followed by 21SF strain. Isoenzyme analysis of parasites from hemocultures obtained from triple infected mice, revealed the patterns of three distinct zymodemes in the same animal. Each Trypanosoma cruzi strain was reisolated after four passages in mice on either the 7 th , 14 th or 30 th day after inoculation with the blood of triple infected mice. Histopathology results demonstrated a significant exacerbation of cardiac and skeletal muscle inflammatory lesions, confirmed by morphometric evaluation, in mice with triple infection. No aggravation of parasitism was detected. The possibility of an enhancement of cellular response in the triple infected mice is suggested. Key-words: Biodemes. Chagas' disease. Reinfections. Trypanosoma cruzi. Zymodemes. RESUMOReinfecções pelo Trypanosoma cruzi em pacientes de áreas endêmicas têm sido mencionadas como fator agravante das manifestações cardíacas na doença de Chagas. No presente estudo, a influência da tríplice infecção com cepas de diferentes biodemas, sobre as lesões do miocárdio e de músculo esquelético foi investigada experimentalmente. Cinqüenta e oito camundongos cronicamente infectados com a cepa Colombiana do Trypanosoma cruzi (Biodema Tipo III) foram sucessivamente reinoculadas como a seguir: 1º grupo -reinfectados com a cepa 21 SF (Tipo II) seguido pela cepa Y (Tipo I); 2º gruporeinfecção com a cepa Y seguida pela cepa 21SF. A análise isoenzimática dos parasitas das hemoculturas obtidas dos animais com tríplice infecção, revelou os padrões dos diferentes zimodemas no mesmo animal. Cada cepa do Trypanosoma cruzi foi re-isolada após quatro passagens em camundongos no 7º, no 14º, ou no 30º dia após a inoculação com o sangue de camundongos com tríplice infecção. Resultados da histopatologia demonstraram uma significante exacerbação das lesões inflamatórias de miocárdio e músculo esquelético, confirmadas pela avaliação morfométrica. Não foi detectada acentuação do parasitismo. A possibilidade de aumento da resposta celular nos animais com tríplice infecção é sugerida. Palavras-chaves: Biodemas. Doença de Chagas. Reinfecções. Trypanosoma cruzi. Zimodemas.

Acute experimental Trypanosoma cruzi infection: establishing a murine model that utilises non-invasive measurements of disease parameters

“…Many aspects of T. cruzi infection have been studied using mouse models, including the infectivity of various tissues (Lenzi et al 1996), the presence of cardiac inflammatory lesions (Marinho et al 1999, Andrade et al 2006, Pavanelli et al 2010, the disturbance of the cardiac electrical conduction system (Eickhoff et al 2010), acute kidney injury (AKI) (Oliveira et al 2009b) and the efficacy of drug treatment regimens (Soeiro et al 2009). However, there are significant differences between the natural disease and experimental models.…”

Paleoparasitology of Chagas disease: a review

“…Positive PCR in nearly all of the fragments tested showed that the parasite was disseminated throughout the body and that the individual presented a high parasite load, typical of the acute phase of the disease and apparently inconsistent with the megacolon, typical of the chronic phase (Fernandes et al 2008). The high parasitic load found in this mummy may also be explained be sequential reinfections: in fact, the worsening of infection with increase of parasitic load has recently been described as the result of reinfection in experimental conditions (Andrade et al 2006).…”

Absence of experimental cross-protection induced by a Trypanosoma cruzi-like strain isolated from bats

“…Animals reinfected with Trypanosoma cruzi strains presented greater electrocardiographic abnormalities than did those infected just once 11 . In addition, a study using three Trypanosoma cruzi strains of different biodemes demonstrated greater histopathological damage in triple infected mice, which was not accompanied by exacerbated parasitemia or tissue parasitism 1 . A similar phenomenon was described in the present study using the Trypanosoma cruzi-like strain RM1 isolated from bats.…”