RESUMO
Combination therapies based on the available drugs have been proposed as promising therapeutic alternatives for many diseases. Clomipramine (CLO) has been found to modify the evolution of the experimental infection. The objective of this study was to evaluate the combined effect of benznidazole (BZ) and clomipramine (CLO) against different life-stages of Trypanosoma cruzi in vitro and their efficacy in a murine model. Life-stages of T. cruzi, BZ-partially-resistant (Y) strain, were incubated with BZ and CLO and isobolograms and combination index (CI) were obtained. Swiss mice were infected with trypomastigotes and different treatment schedules were performed, each of which consisted of 30 consecutive daily doses. Treatment efficacy was evaluated by comparing parasitemia, qPCR, survival and histological analysis. These results were analyzed using multivariate analysis to determine the combined effect of the drugs in vivo. CLO + BZ showed synergistic activity in vitro against the clinically relevant life-stages of T. cruzi. The most susceptible forms were the intracellular amastigotes (CI: 0.20), followed by trypomastigotes (CI: 0.60), with no toxicity upon mammalian cells. The combination of both drugs CLO (1.25â¯mg/kg) and BZ (6.25â¯mg/kg), in vivo, significantly diminished the parasitic load in blood and the mortality rate. CLO + BZ presented a similar inflammatory response in cardiac and skeletal muscle (amount of inflammatory cells) to BZ (6.25 mg/kg). Finally, the results from the principal component analysis reaffirmed that both drugs administered in combination presented higher activity compared with the individual administration in the acute experimental model.
Assuntos
Doença de Chagas/tratamento farmacológico , Clomipramina/farmacologia , Nitroimidazóis/farmacologia , Tripanossomicidas/farmacologia , Trypanosoma cruzi/efeitos dos fármacos , Animais , Clomipramina/uso terapêutico , Relação Dose-Resposta a Droga , Sinergismo Farmacológico , Quimioterapia Combinada , Feminino , Concentração Inibidora 50 , Masculino , Camundongos , Análise Multivariada , Músculo Esquelético/parasitologia , Músculo Esquelético/patologia , Miocárdio/patologia , Nitroimidazóis/uso terapêutico , Parasitemia/tratamento farmacológico , Análise de Componente Principal , Reação em Cadeia da Polimerase em Tempo Real , Tripanossomicidas/uso terapêuticoRESUMO
Chagasic cardiopathy has become one of the most frequent causes of heart failure and sudden death, as well as one of the most common causes of cardio-embolic stroke in Latin America. The myocyte response to oxidative stress involves the progression of cellular changes, primarily targeting the mitochondria and modifying therefore the energy supply. In this paper we analysed the effect of the infection of mice with 2 different strains of Trypanosoma cruzi (Tulahuen and SGO Z12) in the chronic indeterminate stage (75 days post-infection), upon the structure and function of cardiac mitochondria. The structural results showed that 83% of the mitochondria from the Tulahuen-infected mice presented an increase in their matrix and 91% of the mitochondria from the SGO Z12-infected group showed a reduction in their diameter (P < 0.05). When the Krebs cycle and mitochondrial respiratory chain functionality was analysed through the measurement of the citrate synthase and complexes I to IV activity, it showed that their activity was altered in all cases in a similar manner in both infected groups. In this paper we have demonstrated that the chronic indeterminate phase is not 'silent' and that cardiac mitochondria are clearly involved in the genesis and progression to the chronic chagasic cardiopathy when different factors alter the host-parasite equilibrium.
Assuntos
Cardiomiopatia Chagásica/patologia , Cardiomiopatia Chagásica/fisiopatologia , Coração/parasitologia , Interações Hospedeiro-Parasita , Mitocôndrias/enzimologia , Mitocôndrias/parasitologia , Trypanosoma cruzi/patogenicidade , Animais , Cardiomiopatia Chagásica/parasitologia , Doença de Chagas/parasitologia , Doença de Chagas/patologia , Doença de Chagas/fisiopatologia , Doença Crônica , Citrato (si)-Sintase/metabolismo , Modelos Animais de Doenças , Progressão da Doença , Eletrocardiografia , Feminino , Coração/fisiopatologia , Humanos , Masculino , Camundongos , Mitocôndrias/patologia , Miocárdio/metabolismo , Miocárdio/patologia , Parasitemia/parasitologia , Parasitemia/fisiopatologia , Especificidade da Espécie , Trypanosoma cruzi/classificaçãoRESUMO
Treatment of Chagas disease is a controversial issue because the available drugs are highly toxic. Clomipramine is a tricyclic antidepressant drug that inhibits Trypanosoma cruzi's trypanothione reductase, provoking the death of the parasite and preventing the cardiac damage when used for the treatment of acutely infected mice. Here, we studied the effectiveness of clomipramine (5 mg/kg/day for one month) as chemotherapy for T. cruzi-infected mice in the chronic indeterminate stage of the infection. The animals were analyzed in the cardiac chronic phase. Survival of treated animals was 84% while for the untreated ones was 40%; most of the animals presented electrocardiographic abnormalities. Affinity and density of cardiac beta receptors from infected and treated mice were similar to those in the indeterminate phase, showing that clomipramine treatment stopped the increment of functional alterations provoked by the infection, while untreated mice presented affinity and density significantly diminished. Hearts from infected and untreated mice in the chronic stage presented mononuclear cells, necrosis and fiber dissolution while hearts from treated animals showed only isolated inflammatory infiltrates. Present results demonstrate that clomipramine used in the chronic indeterminate phase of the T. cruzi infection modified the natural evolution of the chagasic cardiopathy.