Trypanosoma cruzi biochemical changes and cell death induced by an organometallic platinum-based compound.

Chagas disease is an endemic illness in Latin America caused by the parasite Trypanosoma cruzi. Current chemotherapies are old and inadequate, and the emergence of drug-resistant strains underscores the need of new drugs. Platinum-based complexes have been shown to be a promising approach against parasitic diseases. In this work, the effect of 1,1'-bis(diphenylphosphino)ferrocene pyridine-2-thiolate-1-oxide Pt(II) hexafluorophosphate, Pt-dppf-mpo, was studied on T. cruzi. A promising antitrypanosomal activity was determined for the CL Brener strain with a low cytotoxicity determined using in vitro-cultured mammal cells. The compound uptake in parasites treated with concentrations of 1× and 10× the IC50 value reached ~75% and 19%, respectively. Pt-dppf-mpo induced necrosis after 24 hr of parasite incubation. This event was preceded by depolarization of mitochondrial membrane potential. Cell vitality assays showed high esterase activity in treated parasites. However, despite this increase in metabolic activity, treated epimastigotes showed rounded morphology and loss of flagellum with a reduction in mobility as compound concentration and/or time of incubation was increased. At last, we demonstrate that Pt-dppf-mpo incubation also affects the trypomastigote infection process as well as the infection persistence evaluated as the number of amastigotes per cell in a dose-dependent manner.