Las reinfecciones en la etapa cronica no agravaron la miocardiopatia producida por T. cruzi

BUSTAMANTE, JUAN MANUEL; LO PRESTI, SILVINA; RIVAROLA, WALTER.; FERNANDEZ, ALICIA R; ENDERS, JULIO.; FRETES, RICARDO; PAGLINI, PATRICIA.

Rosario

Simposio; XX Reunion Anual de la Sociedad Argentina de Protozoologia.; 2004

Sociedad Argentina de Protozoologia.

On the basis of the clinical features of Chagas’ disease, the patients could suffer a the digestive form of the disease (10%) or the cardiac one (30%). The variability of the symptoms range from a mild electrocardiographic alteration to sudden death and it may be due to many interrelated factors, two of them are the parasite strain and the reinfections. We have previously demonstrated that reinfections induce severe cardiac damages in the acute and indeterminate phase of the infection. In the present work, we analyse, in albino Swiss mice infected with T. cruzi Tulahuen (Tul) strain (n=70) and SGO-Z12 isolate (n=70) (SGO), the effect of reinfections carried out in at 150 days post infection (dpi). We studied parasitaemia, survival, electrocardiographic abnormalities, heart histopathology and affinity and density of b-adrenergic receptors’. The maximum parasite number was 1,19 ± 0,84 p/ml (160 dpi) for Tul group while there were not parasites in blood in SGO mice. The survival rate in reinfected and Tul infected groups, 320 dpi, was similar (43-50%) while in the group infected with SGO-Z12 isolate it was higher (64%)  (p<0.01) the % of mice that showed at least one kind of electrocardiographic alteration was similar in all groups (150, 185, 240, 320) (52-71%). The b-adrenergic receptors showed in the chronic stage an affinity  (Kd, nM) of 11,21 ± 0,26 and density (Bmax, fmol/mg. Prot) of 53,33 ± 0,71 for Tul and for SGO a affinity of 7,32 ± 0,19 and a density 184,02 ± 2,10. These values were significantly different in the groups reinfected (p<0.01). The heart histopathology in all groups showed the typical alterations of the chagasic cardiomiopahty. These data showed that the reinfected process in the early chronic phase of experimental Chagas’ disease developed an immune response that did not modify the natural history of Chagas’ disease.