In vitro and in vivo efficacy of miltefosine and benznidazole combination in experimental Trypanosoma cruzi infection

GULIN, E; ALTCHEH, J; BISIO, M; ROCCO, DM; SOLANA, ME; GARCÍA BOURNISSEN, F

Varadero

Taller; 1er Taller internacional: Modelos animales e investigación preclínica (Animod 2019); 2019

Centro de Ingeniería Genética y Biotecnología de la Habana (CIGB), la Sociedad Cubana de Farmacología y el Centro Nacional para la Producción de Animales de Laboratorio (CENPALAB).

Treatment for Chagas disease are currently limited to benznidazole (BZ) or nifurtimox (NFX). Alternatives are lacking in part due to high costs of drug development. Combinatory therapy is a proven strategy to improve efficacy, reduce treatment schedules, doses, and lower side effects rates. The leishmaniasis drug miltefosine (MLT) has potent in vitro activity and in vivo partial agonism against T. cruzi. The objective of this study was to evaluate MLT in combination with BZ using in vitro and in vivo models. MLT+BZ activity was assayed on trypomastigotes and intracellular amastigotes (VD strain). Trypomastigotes lysis and amastigote development inhibition was evaluated after being exposed to fixed concentration method. The fractional inhibitory concentration index (FICI) was calculated as: FICI=(A IC50 in combination/A IC50 alone)+(B IC50 in combination/B IC50 alone) and interpreted as: 0.5˂1, synergistic; ≥1, additive;≥ 4 antagonistic interaction.For in vivo treatment, 6 weeks-old BALB/c female mice were infected with 500 trypomastigotes by intraperitoneal route. At parasitemia onset, treatment was randomly assigned: Non-treated (NT); BZ 5 mg/kg; MLT 25 mg/kg; MLT 25 mg/kg+BZ 5 mg/kg; MLT 50 mg/kg+BZ 50 mg/kg; BZ 100 mg/kg and given orally for 20 consecutive days. Effects on parasitemia, mortality and parasitic load (qPCR) in blood were recorded.FICI for trypomastigotes was 0.753 (i.e. synergism), while for amastigotes inhibition was 1.089 (i.e. additive). In the murine model, all treatments decreased parasitemia (p