Study of the pathogenesis of cardiac lesions in dogs with visceral leishmaniasis

Abstract

Visceral leishmaniasis (VL) is caused by protozoa of the genus Leishmania, occurring on all continents and affecting several vertebrate species, including man. The lesions of the disease occur by a differentiation of immune response, which tends to evolve towards a humoral immune response, leading to deposition of immune complexes in various organs, which contributes to the pathogenesis of symptoms. Among the organs affected, we highlight the kidneys, whose injury is the leading cause of mortality in the disease. Despite reports of cardiac involvement in dogs with VL be rare, studies realized by our research group demonstrated the occurrence of histopathological changes in the myocardium of 100% of animals evaluated, and the most frequent findings the presence of inflammatory infiltrate, and necrosis of cardiomyocytes fibrosis. Unlike previous studies, amastigotes of the parasite were observed in 66.7% of dogs, suggesting an involvement of the parasite in the development of lesions. However, the pathogenesis of cardiac lesions has not been fully elucidated and, like other organs, there may be involvement of the immune system. Thus, this study aims to evaluate the immune response in heart tissue of dogs naturally affected by VL. Thus, we'll evaluate the immunostaining for CD3 +, CD4 +, CD8 +, CD21+, CD79 +, CD68 + and nitric oxide synthase; quantitation of IL-7, IL-12, IL-15, INF-³, TNF-± and metalloproteases MMP-2 and -9 in four fragments heart of dogs naturally affected by the disease. (AU)