Quantitative analysis of cardiac lesions in chronic canine chagasic cardiomyopathy

Abstract

Lesions observed in chronic chagasic cardiopathy frequently produce electrocardiographic alterations and affect cardiac function. Through a computerized morphometrical analysis we quantified the areas occupied by cardiac muscle, connective and adipose tissues in the right atrium of dogs experimentally infected with Trypanosoma cruzi. All of the infected dogs showed chronic myocarditis with variable reduction levels of cardiac muscle, fibrosis and adipose tissue replacement. In the atrial myocardium of dogs infected with Be78 and Be62 cardiac muscle represented 34 and 50%, fibrosis 28 and 32% and adipose tissue 38 and 18%, respectively. The fibrosis observed was both diffuse and focal and mostly intrafascicular, either partially or completely interrupting the path of muscle bundles. Such histological alterations probably contributed to the appearance of electrocardiographic disturbances verified in 10 out 11 dogs which are also common in human chronic chagasic cardiopathy. Fibrosis was the most important microscopic occurrence found since it produces rearrangements of collagen fibers in relation to myocardiocytes which causes changes in anatomical physiognomy and mechanical behavior of the myocardium. These abnormalities can contribute to the appearance of cardiac malfunction, arrythmias and congestive cardiac insufficiency as observed in two of the analyzed dogs. Strain Be78 caused destruction of atrial cardiac muscle higher than that induced by strain Be62.

Histological Characterization of Dilated Cardiomyopathy in the Juvenile Toy Manchester Terrier

“…However, the histologic changes could be more specific for a particular disease process than previously thought. 44 For example, fatty infiltration-degeneration may be a consequence of cardiomyocyte loss due to inflammatory insults such as myocarditis 9 or resulting from other injurious stimuli, including antineoplastic agents. 26 The attenuated wavy fiber form could be associated with acute myocardial ischemia 18 or represent an early change due to cytoskeletal defects.…”

“…Postmortem reports were available for 14 TMTs that were confirmed to be affected based on microscopic lesions identified by microscopic examination of submitted slides or paraffin-embedded tissues (TMT CM Nos. [1][2][3][4][5][6][7][8][9][10][11][12] or based on microscopic cardiac lesions described in the submitted postmortem reports (TMT CM Nos. 13 and 14).…”

“…Five dogs (TMT CM Nos. 1,5,8,9, and 14 with ratios of 1.07, 1.44, 1.07, 1.08, and 1.00, respectively) had increased HW/BW ratios (normal range is 0.58%-0.94% of total body weight), 48 and the remaining dog had a decreased ratio (TMT CM No. 12 with a ratio of 0.56).…”

Canine trypanosomiasis: etiology of infection and implications for public health

“…From the anatomopathological and histopathological points of view, the most important aspect of this model is that it reproduces a form of fibrous chronic chagasic cardiopathy that is very similar to that observed in humans (50,51).…”

Seroprevalencia de la infección por Trypanosoma cruzi en Canis familiaris del estado Sucre, Venezuela

“…La fase aguda puede ser fatal en los animales jóvenes o avanzar hasta el desarrollo de cardiopatía con muerte súbita, similar a la observada en humanos durante la fase crónica (19). Por esta razón, los perros se han propuesto como modelos para el estudio de los cambios patológicos en el desarrollo de la enfermedad de Chagas (20).…”