Avaliação dos efeitos da terapia com imunoglobulina humana em modelo murino de cardiomiopatia chagásica crônica

Abstract

INTRODUCTION: Chagas disease, caused by the protozoan Trypanosoma cruzi, is one of the most important causes of heart failure in America. Alternative therapies have been investigated as potential therapeutic options for patients with this disease. This study evaluated the effects of therapy with human immunoglobulin in an experimental model of chronic chagasic cardiomyopathy. METHODS: C57BL/6 mice were infected with 1000 trypomastigotes of the Colombian strain of T. cruzi, and after eight months of infection were treated with intravenous human immunoglobulin or albumin (control). Before and after 2 months of treatment, infected animals and normal controls underwent cardiac evaluation including electrocardiogram, echocardiography and treadmill test. The immunoglobulin and albumin groups were treated, respectively, with 1 mg/kg/day of human immunoglobulin or albumin, intraperitoneally, for five consecutive days. All animals were sacrificed under anesthesia, after 2 months of treatment, for histopathological analysis of the heart. RESULTS: No improvement was observed in cardiovascular function in animals treated with immunoglobulin compared to animals treated with albumin. There was an increasing in the number of animals with complete atrioventricular block in the immunoglobulin group. However, sections of hearts in immunoglobulin group had a significantly reduced number of inflammatory cells (p <0,01) and area of fibrosis (p <0,001), compared to animals treated with albumin. In animals treated with immunoglobulin, there was evidence of arteritis marked with immune complex deposition in the intima of arterioles. The concentrations of serum cytokines were increased in the group treated with immunoglobulin in comparison to the other groups (uninfected and treated with albumin mice). When considering cytokines production in heart extract, there were no differences observed in production of IFN-γ, TNF-α and IL-10 between the groups treated with immunoglobulin and albumin. CONCLUSION: Thus, we concluded that immunoglobulin therapy has neither not shown anti-inflammatory efficacy nor improvement in cardiovascular function in a murine model of chronic chagasic cardiomyopathy.