Involvement of the autonomic nervous system in Chagas heart disease

Abstract

The autonomic nervous system and especially the intracardiac autonomic nervous system is involved in Chagas' disease. Ganglionitis and periganglionitis were noted in three groups ofpatients dying with Chagas'disease: 1) Those in heart failure; 2) Those dying a sudden, non violent death and; 3) Those dying as a consequence ofaccidents or homicide. Hearts in the threegroups also revealed myocarditis and scattered involvement of intramyocardial ganglion cells as well as lesions of myelinic and unmyelinic fibers ascribable to Chagas'disease. In mice with experimentally induced Chagas' disease weobserved more intensive neuronal lesions of the cardiac ganglia in the acute phase of infection. Perhaps neuronal loss has a role in the pathogenesis of Chagas cardiomyopathy. However based on our own experience and on other data from the literature we conclude that the loss of neurones is not the main factor responsible for the manifestations exhibited by chronic chagasic patients. On the other hand the neuronal lesions may have played a role in the sudden death ofone group of patients with Chagas'disease but is difficult to explain the group of patients who did not die sudderly but instead progressed to cardiac failure.

Impaired autonomic control of heart interval changes to Valsalva manoeuvre in Chagas' disease without overt manifestation

“…The more probable pathogenetic mechanism is the primary direct chronic inflammatory or autoimmunological damage of ganglia and/or neuronal fibres (Lopes and Tafuri, 1983;Oliveira, 1985), as classically accepted on the basis of human and experimental animal studies (Junqueira et al, 1992;Marin-Neto, 1998). The possibility that in chagasics with the indeterminate form of disease, the autonomic disturbance is only due to neuroganglionic inflammation, is reinforced by the observation in the experimental rat model of T. cruzi infection developed in our laboratory that the exclusive presence of ganglionic and/or neuronal inflammation without neuroganglionic depopulation was sufficient to cause depression of the phenylephrine-induced baroreflex bradycardia (Chapadeiro et al, 1991).…”

“…In the chronic-isolated or combined cardiac and digestive forms of Chagas' disease, a striking pathological feature is the involvement in variable degree of the autonomic intrinsic innervation of heart (Lopes and Tafuri, 1983;Oliveira, 1985). The human and experimental indeterminate forms present less conspicuous lesions of cardiac intrinsic innervation, which are usually represented by discrete to moderate focal or zonal chronic neuroganglionitis (Lopes and Tafuri, 1983;Andrade, 1984;Oliveira, 1985;Chapadeiro et al, 1991).…”

“…The human and experimental indeterminate forms present less conspicuous lesions of cardiac intrinsic innervation, which are usually represented by discrete to moderate focal or zonal chronic neuroganglionitis (Lopes and Tafuri, 1983;Andrade, 1984;Oliveira, 1985;Chapadeiro et al, 1991). Cardiac autonomic damage has also been observed in acute and chronic experimental Trypanosoma cruzi infection in mice (Tafuri, 1970;Souza et al, 1996), dogs (Andrade, 1984;Machado et al, 1998), rats (Chapadeiro et al, 1991;Junqueira et al, 1992), and hamsters (Chapadeiro et al, 1999) among other animal models.…”

Chagas' heart disease

“…Striking autonomic neuronal depopulation and nerve degeneration, mostly in the cardiac, esophageal and colon tissues, is another typical feature of chronic Chagas' disease 82,91,92 . However, no correlation exists between the intensity of neuronal destruction and dilation of the organ or other microscopic indices of myocarditis in the chronic phase 91 .…”

“…However, no correlation exists between the intensity of neuronal destruction and dilation of the organ or other microscopic indices of myocarditis in the chronic phase 91 .…”