[Myocardial cell response to Trypanosoma cruzi infection]

The aim of this study is to establish the response of cardiac myocytes to the infection with Trypanosoma cruzi. The role of myocardial cell proliferation on heart remodelation and the ability of these cells to produce nitric oxide and control intracellular parasite growth during T. cruzi infection were evaluated. The presence of proliferating cell nuclear antigen (PCNA) was determined in myocardial cells of Wistar rats infected with T. cruzi, resulting in a significant increase of PCNA+ labelling in all stages of disease. The ability of myocardial cells to control growth of intracellular parasites and the production of nitric oxide were evaluated in cultures of cardiac myocytes obtained from neonatal rats. Different combinations of cytokines were added to culture media. The number of cardiac cells displaying intracellular amastigotes was lower in cultures supplemented with IL-1b, TNF-a and IFN-g than with other cytokine combinations and controls. The addition of cytokines resulted also in an increase of nitric oxide production in both infected and non-infected controls. These results demonstrate that myocardial cells participate actively in the response of the heart to the infection with T. cruzi.