Effects of Low Doses of Benznidazole Nanosystems in Both Acute and Chronic Experimental Chagas Disease: A New Promising Treatment Regimen

RIAL M.; ARRÚA E.; SCALISE M.; FICHERA L.; SALOMON C.

Congreso; 2017 AAPS ANUAL MEETING AND EXPOSITION; 2017

AAPS

PurposeChagas? disease, a neglected disease caused by the protozoan Trypanosoma cruzi and transmitted by triatomine bugs, is the most prevalent parasitic disease in Latin America. Lately, and due to movement of infected people from endemic areas to non-endemicregions Chagas disease has been detected in North America, Europe and Japan, also. Benznidazole (BNZ) is one of the two available drugs for the treatment of Chagas disease. Although it is the drug of choice in many regions, BNZ has serious undesirable effectsincluding anorexia and weight loss, nausea, headache, nervous excitation and allergic dermatitis. Therefore, alternative treatments using lower doses of BNZ is urgently required. The aim of this work to evaluate the efficacy of low doses of BNZ nanoparticlesduring the acute phase in mice infected with TcN that were immunosuppressed during the chronic stage of disease. Additionally, production of T. cruzi-specific antibodies and cardiac tissue inflammation in mice after treatment with this BNZ nanoformulationswere also investigated.MethodsBNZ nanoparticles were prepared by solvent diffusion method. BNZ (200 mg) was dissolved in ethanol (10 ml). The solution was injected (1 ml min−1) into water (20 ml) containing P188 (300 mg) under stirring (1000 rpm/60 min). The solution was stirred (500 rpm) for 18 h at room temperature to allow solvent evaporation. Nanoparticles were recovered by centrifugation for 20 min (15000 rpm), washed twice with distilled water, frozen overnight at -20 oC and freeze-dried (48 hours).Animal model.Five groups of ten one-month-old female C3H/HeN mice, were inoculated intraperitoneally with 1000 culture-derived trypomastigotes of the TcN. Infected mice were divided into the following groups (n=10): (1) infected mice without treatment, (2) infected mice treated with raw BNZ with daily doses of 50 mg/kg body weight for 30 days (2 to 32 dpi) (R-BNZ 50), (3) infected mice treated with BNZ nanoparticles for 30 days with daily doses of 50 mg/kg/day (BNZ-nps 50), (4) infected mice treated with BNZ nanoparticles for30 days with daily doses of 25 mg/kg/day (BNZ-nps 25), (5) infected mice treated with BNZ nanoparticles for 30 days with daily doses of 10 mg/kg/day (BNZ-nps 10). R-BNZ and BNZ-nps were dispersed in olive oil and orally administered to mice, the controlgroup received olive oil alone.ResultsBNZ nanoparticles Following the methodology of nanoprecipitation, small particles of about 63.3 ± 2.82 nm, with zeta potential of -18.30 ± 1.0, and a size distribution (polydispersity index) of 3.35 ± 0.1 were obtained.Course of infection.To determine whether BNZ nanoformulations treatments affect the course of infection and survival rate of C3H/HeN mice, such nanoparticles were orally administered at 10, 25 and 50 mg/kg/d and compared with raw BNZ (R-BNZ) at a dose of 50 mg/kg/d. Allinfected mice treated with BNZ, no matter whether nanoparticle-formulated or raw BNZ, survived until the end of the experiment (92 days p.i.). On the other hand, only 15% of the non-treated infected mice survived.HistopathologyAs expected, the myocardium of untreated infected mice showed extensive and multiple inflammatory foci of mononuclear cell infiltrates and some necrotic areas with structural alterations and fibrotic foci. Parasite nests were absent in heart tissues of mice thatsurvived the acute stage. TcN-infected mice treated with raw BNZ (50 mg/kg/d) exhibited similar inflammatory damage than the untreated infected group. In contrast, a significant decrease of inflammatory cells in heart tissue was observed after treatment withBNZ-nps at a dosage of 25 and 50 mg/kg/d.ConclusionBNZ nanoparticles could be used as an alternative to the conventionally used treatment regimen, where BNZ is applied at 100mg/kg/day causing, very often, serious adverse side effects.