Andréa Pereira de Souza

Enzymatic markers of heart lesion in mice infected with Trypanosoma cruzi and submitted to benznidazole chemotherapy

Abstract Creatine kinase (CK total and CK-MB) were studied as markers of lesion progression induced by Trypanosoma cruzi infection. After 3 weeks mice infected with 104 parasites showed an increase in both enzyme levels and in their frequency distribution. A trend to increase was already detected in the 2nd week. A short duration per os treatment with benznidazole (Bz) prevented the occurrence of tissue lesions, since no changes were observed in enzymes. However, in the 4th week, about 40% of Bz-treated mice showed an increase in CK-MB, as did those that survived until the 8th week. Long-term treatment with Bz in drinking water of mice infected with 102 parasites showed, after 32 weeks, a partial reversion of the occurrence of high CK-MB levels from 85.7% to 50%. We found a positive correlation between inflammatory infiltrates and CK-MB levels, indicating that this marker could be useful to monitor the occurrence of experimental chagasic myocarditis.

Trypanosoma cruzi: host selenium deficiency leads to higher mortality but similar parasitemia in mice.

Selenium is an essential trace element and its deficiency was implicated in heart diseases. We recently showed low Se levels in chronic chagasic patients with cardiomyopathy. Herein, mice were depleted in Se by feeding the mothers with chow containing only 0.005 mg Se/kg and maintaining this diet for offspring, that were further infected with Trypanosoma cruzi. Survival rate was significantly lower in Se deficient than in control mice. Parasitemia was similar in all groups. Necrotic heart lesions were found after infection (high CK-MB levels). No outbreaks of parasite growth were detected in chronic survivors submitted or not to a second Se depletion. The present results confirm our hypothesis that a nutritional deficiency in Se is associated to a higher mortality during T. cruzi infection. The potential beneficial effect of Se supplementation is a perspective. Hypothesis to explain the higher susceptibility of Se-depleted mice to T. cruzi infection are discussed.

Magnetic resonance imaging in experimental Chagas disease: a brief review of the utility of the method for monitoring right ventricular chamber dilatation

Chagas’ disease caused by infection with Trypanosoma cruzi leads to a myocardiopathy that evolves from the acute to the chronic phase. Magnetic resonance imaging (MRI) is an important tool for monitoring cardiac morphology and function both in humans and in animals. In the present work, we present a brief review of MRI applications for the study of ventricular hypertrophy and dilatation of the right ventricle in murine models of Chagas’ disease. Studies using MRI demonstrate an increase in right ventricular chamber dimension during both phases of infection, indicating that increase of the right ventricle is a marker for experimental chagasic myocardiopathy. Based on previous studies using MRI in these models we propose that this technique is an excellent approach for monitoring heart functionality from the acute through the chronic phase of infection in different parasite–host pairs and for monitoring the efficacy of cardioprotective or immune-therapeutic agents.

Would selenium supplementation aid in therapy for Chagas Disease

Chagas disease, a neglected tropical disease discovered over 100 years ago, is caused by the intracellular parasite Trypanosoma cruzi and is most frequently associated with chronic cardiomyopathy and digestive disorders. Initial invasion of cells is followed by progressive inflammatory destruction of heart, muscles, nerves, and gastrointestinal (GI) tract tissue. Approximately 30% of patients progress to a chronic cardiomyopathy associated with increased morbidity and mortality. Seven to 10% of patients develop megasyndromes involving the GI tract, in particular, the esophagus and the colon. Results from several studies suggest that selenium (Se) deficiency could be an important factor in the pathogenesis of Chagas disease. In this opinion article, Se supplementation is proposed as an adjuvant therapy for treatment of chronic Chagas disease.