Benznidazole prevents endothelial damage in an experimental model of Chagas disease

Highlights

• We administered 30 or 100 mg/kg/day benznidazole to Chagasic mice early in the infection.

• Parasitaemia, mortality, cardiac and endothelial dysfunction markers were measured.

• 30 mg/kg Benznidazole prevents cardiac damage and modulates endothelial activation.

Abstract

Objectives

To evaluate the effect of benznidazole on endothelial activation in a murine model of Chagas disease.

Methods

A low (30 mg/kg/day) and a high (100 mg/kg/day) dose of benznidazole were administered to mice infected with Trypanosoma cruzi during the early phases of the infection. The effects of the treatments were assessed at 24 and 90 days postinfection by evaluating the parasitaemia, mortality, histopathological changes and expression of ICAM in the cardiac tissue. The blood levels of thromboxane A₂, soluble ICAM and E-selectin were also measured. T. cruzi clearance was assessed by the detection of parasite DNA in the heart tissue of infected mice.

Results

Benznidazole decreased the cardiac damage induced by the parasite, and amastigote nests disappeared at 90 days postinfection. Both doses cleared the parasite from the cardiac tissue at 24 and 90 days postinfection. In addition, benznidazole decreased the thromboxane levels and normalized the plasma sICAM and sE-selectin levels by 90 days postinfection.

Conclusions

Early administration of benznidazole at a dose as low as 30 mg/kg eradicates T. cruzi from cardiac tissue. Additionally, benznidazole prevents cardiac damage and modulates endothelial activation as part of its antichagasic activity.

Introduction

Chronic Chagas disease is one of the most devastating causes of cardiac failure (Barbosa et al., 2011, Vilas Boas et al., in press). Although extensive public health measures to control vectors and prevent blood transmission have decreased the incidence and prevalence of this disease, current therapies do not possess high efficacies. Additionally, human migration has provided a source of the disease in non-endemic countries, increasing the risk of blood-borne or congenital transmission in regions where systematic blood testing is not performed (Munoz et al., 2009). Thus, understanding the mechanisms of current therapies and identifying other therapeutic strategies will help to improve the treatment of Chagas disease, particularly during the chronic phase of the disease.

One of the pathophysiologic mechanisms involved in chronic chagasic cardiomyopathy (CCC) is the presence of microvascular abnormalities and ischemia, events that are related to endothelial activation or dysfunction due to thromboxane A₂ (TXA₂)-mediated platelet aggregation (Constans and Conri, 2006, Keller et al., 2003, Marin-Neto et al., 2007, Rossi et al., 2010). TXA₂ is produced by both the parasite and the host (Ashton et al., 2007, Rossi et al., 2010). Activation of the TXA₂ receptors increases the expression of adhesion molecules (Daniel et al., 1999, Ishizuka et al., 1998) such as intercellular adhesion molecule-1 (ICAM-1 or CD54), vascular cell adhesion molecule-1 (VCAM-1 or CD106) and E-selectin (Kobayashi et al., 2007). The expression of these molecules is increased in the T. cruzi-infected myocardium and could participate in the establishment of the chagasic infection by interaction with the T. cruzi trypomastigotes (Huang et al., 1999).

Benznidazole reduces cardiac abnormalities in a chronic murine model of Chagas disease (Garcia et al., 2005), mainly related to its trypanocidal activity. However, the therapeutic scheme employed in that study was administered over a long period of time, and the benznidazole dose used corresponds to the maximum effective dose reported for mice (benznidazole 100 mg/kg/day). The effect of benznidazole on endothelial function has not yet been explored. Recent reports show that benznidazole modulates pro-inflammatory cytokines and NO release in macrophages by inhibiting NF-κB (Manarin et al., 2010). Because NF-κB is capable of inducing ICAM-1 expression, benznidazole may also modulate the inflammatory response elicited by the parasite (Piaggio et al., 2001). Therefore, benznidazole could protect the host's endothelial environment during a chronic T. cruzi infection. Herein, we determined the effect of low dose, short duration benznidazole therapy on cardiac abnormalities. Using a chronic Chagas murine model, we investigated the effect of the therapy on endothelium adhesion molecules and cardiac histopathology at 90 days postinfection (d.p.i.). Our results suggest that a low dose of benznidazole decrease the expression of the adhesion molecules and improves the histopathology of the cardiac tissue. This study provides evidence of an efficacious low-dose therapy that could decrease the risk of adverse dose-related events.