Differential tissue distribution of discrete typing units after drug combination therapy in experimental Trypanosoma cruzi mixed infection.

The aim of the present work was to evaluate the distribution of the different clones of the parasite prevailing after treatment with benznidazole (BZ) and clomipramine (CLO), in mice infected with Trypanosoma cruzi, Casibla isolate which consists of a mixture of two discrete typing units (DTUs). Albino Swiss mice were infected and treated with high and low concentrations of BZ (100 or 6.25 mg/kg), CLO (5 or 1.25 mg/kg), or the combination of both low doses (BZ6.25 + CLO1.25), during the acute phase of experimental infection. Treatment efficacy was evaluated by comparing parasitaemia, survival and tissular parasite presence. For DTUs genotyping, blood, skeletal and cardiac muscle samples were analysed by multiplex quantitative polymerase chain reaction. The combined treatment had similar outcomes to BZ6.25; BZ100 was the most effective treatment, but it failed to reach parasite clearance and produced greater histological alterations. Non-treated mice and the ones treated with monotherapies showed both DTUs while BZ6.25 + CLO1.25 treated mice showed only TcVI parasites in all the tissues studied. These findings suggest that the treatment may modify the distribution of infecting DTUs in host tissues. Coinfection with T. cruzi clones belonging to different DTUs reveals a complex scenario for the treatment of Chagas disease and search for new therapies.

Analysis of mitochondrial enzymatic activity in blood lymphomonocyte fractions during infection with different Trypanosoma cruzi strains.

Proinflammatory and inflammatory mediators induced by Trypanosoma cruzi infection increase the oxidative stress, generating toxicity for cells targeting mitochondria of different tissues. We studied the activity of citrate synthase and complexes I-IV of respiratory chain in mitochondria of blood lymphomonocyte fraction, from albino Swiss mice infected with different isolates of T. cruzi , during Chagas disease evolution. Complexes I-IV were modified in infected groups (p<0.05) in all the stages, and an inflammatory process of different magnitudes was detected in the heart and skeletal muscle according to the isolate. The citrate synthase activity presented modifications in the SGO Z12 and the Tulahuen group (p<0.05). Hearts showed fiber fragmentation and fibrosis; skeletal muscle presented inflammatory infiltrates and in the Tulahuen infected group, there were also amastigote nests. The inflammatory processes produced an oxidative stress that induced different alterations of mitochondrial enzymes activities in the lymphomonocyte fraction that can be detected by a simple blood extraction, suggesting that they could be used as disease markers, especially in the indeterminate phase of Chagas disease.

Differential tissue distribution of Trypanosoma cruzi during acute experimental infection: Further evidence using natural isolates.

In the present work, we evaluated the effect of mixed Trypanosoma cruzi infections, studying the biological distribution of the different parasites in blood, heart and skeletal muscle during the acute phase. Albino Swiss mice were infected with different parasite strain/isolates or with a combination of them. The parasites in the different tissues were typified through specific PCR, population variability was analyzed through RFLP studies and parasitological and histopathological parameters were evaluated. We found a predominance of TcII and TcVI in all tissues samples respect to TcV and different parasite populations were found in circulation and in the tissues from the same host. These results verify the distribution of parasites in host tissues from early stages of infection and show biological interactions among different genotypes and populations of T. cruzi.