Involvement of the beta-adrenergic system in the cardiac chronic form of experimental Trypanosoma cruzi infection.
Changes in the cardiac beta-adrenergic system in early stages of Trypanosoma cruzi infection have been described. Here, we studied an early (135 days post-infection-p.i.) and a late stage (365 days p.i.) of the cardiac chronic form of the experimental infection (Tulahuen or SGO-Z12 strains), determining plasma epinephrine and norepinephrine levels, beta-receptor density, affinity and function, cardiac cAMP concentration and phosphodiesterase activity, cardiac contractility, and the presence of beta-receptor autoantibodies. Tulahuen-infected mice presented lower epinephrine and norepinephrine levels; lower beta-receptor affinity and density; a diminished norepinephrine response and higher cAMP levels in the early stage, and a basal contractility similar to non-infected controls in the early and augmented in the late stage. The Tulahuen strain induced autoantibodies with weak beta-receptor interaction. SGO-Z12-infected mice presented lower norepinephrine levels and epinephrine levels that diminished with the evolution of the infection; lower beta-receptor affinity and an increased density; unchanged epinephrine and norepinephrine response in the early and a diminished response in the late stage; higher cAMP levels and unchanged basal contractility. The SGO-Z12 isolate induced beta-receptor autoantibodies with strong interaction with the beta-receptors. None of the antibodies, however, acted a as beta-receptor agonist. The present results demonstrate that this system is seriously compromised in the cardiac chronic stage of T. cruzi infection.
Lo Presti
M S
MS
Cátedra de Física Biomédica, Universidad Nacional de Córdoba. Santa Rosa 1085, Córdoba PC 5000, Argentina. SilviLoPresti@gmail.com
Rivarola
H W
HW
Fernández
A R
AR
Enders
J E
JE
Levin
G
G
Fretes
R
R
Cerban
F M
FM
Garrido
V V
VV
Paglini-Oliva
P
P
D000318:Adrenergic beta-Agonists / Q000097:blood / Q000494:pharmacology; D000818:Animals; D000918:Antibody Specificity; D001323:Autoantibodies / Q000097:blood / Q000276:immunology; D002598:Chagas Cardiomyopathy / Q000097:blood / Q000473:pathology / Q000503:physiopathology*; D002908:Chronic Disease; D000242:Cyclic AMP / Q000378:metabolism; D004837:Epinephrine / Q000097:blood / Q000494:pharmacology; D006321:Heart / Q000187:drug effects / Q000503:physiopathology; D051379:Mice; D009200:Myocardial Contraction / Q000187:drug effects; D009206:Myocardium / Q000378:metabolism / Q000473:pathology; D009638:Norepinephrine / Q000097:blood / Q000494:pharmacology; D010727:Phosphoric Diester Hydrolases / Q000378:metabolism; D011943:Receptors, Adrenergic, beta / Q000032:analysis / Q000378:metabolism*; D014349:Trypanosoma cruzi
D000318:Adrenergic beta-Agonists; D001323:Autoantibodies; D011943:Receptors, Adrenergic, beta; D000242:Cyclic AMP; D010727:Phosphoric Diester Hydrolases; D009638:Norepinephrine; D004837:Epinephrine