The Pathologic Lesions of the Cardiac Autonomic Nervous System in Chronic Chagas' Myocarditis

Chagas' heart disease

“…Necropsy findings in humans have been correlated with observations in several animal models of experimental Chagas' disease reproducing the various stages of the disease 43,[78][79][80][81][82][83][84][85][86] . Endomyocardial biopsy has also been used in subsets of the chagasic population, including patients in the indeterminate phase 46,87 .…”

“…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 .…”

“…Neurogenic mechanisms -Necropsy studies in humans clearly demonstrated intense cardiac neuronal depopulation in the various Chagas' disease stages 49,[79][80][81][82] . These findings were reproduced by investigations in animal models of the disease 49,[83][84][85][86][96][97][98][99] .…”

“…Thus, the frequency and the intensity of this abnormality are quite variable, and a mismatch between the presence of autonomic denervation and ventricular dysfunction is often seen 77,92,96,[101][102][103] . Differences in T. cruzi strain and/or regional environment are likely causes for variable neurotropism observed in several regions 99 .…”

Pathogenesis and Pathology of Chagas' Chronic Myocarditis

“…These findings led to the "neurogenic hypothesis" (Köberle, 1959), which explained all megas in Chagas' disease as a consequence of neuronal depletion. Although many other authors claimed to have confirmed this finding (Mott & Hagstrom, 1965, Oliveira J. S., 1985, other authors called to attention about the criteria used to diagnose neuronal depletion because of the great variability in the number of neurons in autonomic ganglia (Rossi L., et al, 1994) and they also remarked that the only right criterion to establish neuronal depletion is the presence of proliferation of satellite cells, with the formation of Terplan's nodules, a characteristic lesion described as proliferating satellite cells which replace degenerating neurons, forming nodular structures. These lesions, once considered patognomonic, can be found in other cardiomyopathies (Rossi L., et al, 1994).…”