Beta-adrenergic system alterations in Chagas disease

LO PRESTI MS; RIVAROLA HW; PAGLINI PA

La Plata

Jornada; XVIII Meeting ISHR Latin American; 2010

ISHR Latin American

The b-adrenergic system is the most important regulator of cardiac function, and therefore it could be altered in the myocardiopathy produced by the Trypanosoma cruzi infection. Key elements of this system were studied, in order to infer it’s functionality and the presence of alterations, in mice hearts infected with two parasite strains (Tulahuen and SGO Z12): plasmatic catecholamines by RP-HPLC; affinity and density of cardiac b-adrenergic receptors (b-AR) by radioactive binding; b-AR functionality in response to exogenous catecholamines; cAMP levels by ELISA; and cardiac contractility as the final response of the system. Mice survival, parasitaemia levels, cardiac histopathology and cardiac electric activity were also studied. Histopathological and electrocardiographic alterations augmented with the evolution of the infection; the survival diminished. The cardiac b-adrenergic system was altered at different levels, showing differences regarding the parasite strain used: diminished plasma catecholamines; b-AR with diminished affinity, especially in Tulahuen-infected mice; higher levels of cAMP in the earlier stages of the infection; and a diminished response to epinephrine and norepinephrine mainly in SGO Z12-infected mice. Present results show that this system is seriously compromised along the T. cruzi infection, with alterations that are responsible for the progressive cardiac damage characteristic of this disease.