title: Proinflammatory and cytotoxic effects of hexadecylphosphocholine (miltefosine) against drug-resistant strains of Trypanosoma cruzi.
abstract: The increased resistance of the protozoan parasite Trypanosoma cruzi to nitro derivatives is one of the major problems for the successful treatment of Chagas' disease. In the present study, we have tested the effects of 1-O-hexadecylphosphocholine (miltefosine) against strains of T. cruzi that are partially resistant (strain Y) and highly resistant (strain Colombiana) to the drugs in clinical use. As expected, epimastigotes of strain Colombiana showed higher levels of resistance to benznidazole than those of strain Y. However, the level of resistance to miltefosine was the same for both strains. This alkylphospholipid was also extremely toxic against intracellular amastigotes of both strains. This ether-lipid analogue induced in a dose-dependent manner the production of tumor necrosis factor alpha and nitric oxide (NO) radicals by infected and noninfected macrophages, suggesting that miltefosine may activate macrophages in vitro. Nevertheless, the cytotoxic effect of miltefosine against intracellular amastigotes was independent of the amount of NO produced by the infected macrophages since the same dose-response curves for miltefosine were observed when the NO production was blocked by the NO synthase inhibitor N(G)-monomethyl-L-arginine monoacetate. Preliminary in vivo studies with BALB/c mice infected with strain Y indicated that oral miltefosine promoted survival and reduced the parasitemia to levels comparable to those observed when benznidazole was used. Four months after treatment, no parasites were detected in the blood or spleen tissue sections maintained in culture. Together, these results support the hypothesis that miltefosine may be used for the treatment of Chagas' disease, including cases caused by resistant strains of T. cruzi.
authors.affiliation: Instituto de Biofísica Carlos Chagas Filho, Rio de Janeiro-RJ, 21944-970, Brazil.
authors.forename: Victor B
authors.initials: VB
authors.lastname: Saraiva
authors.forename: Daniel
authors.initials: D
authors.lastname: Gibaldi
authors.forename: José O
authors.initials: JO
authors.lastname: Previato
authors.forename: Lucia
authors.initials: L
authors.lastname: Mendonça-Previato
authors.forename: Marcelo T
authors.initials: MT
authors.lastname: Bozza
authors.forename: Célio G
authors.initials: CG
authors.lastname: Freire-De-Lima
authors.forename: Norton
authors.initials: N
authors.lastname: Heise
mesh_terms: D000818:Animals; D000981:Antiprotozoal Agents / Q000494:pharmacology*; D014355:Chagas Disease / Q000188:drug therapy* / Q000469:parasitology / Q000473:pathology; D004351:Drug Resistance; D005122:Exudates and Transudates / Q000166:cytology; D007249:Inflammation / Q000473:pathology; D008297:Male; D051379:Mice; D008807:Mice, Inbred BALB C; D009569:Nitric Oxide / Q000378:metabolism; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors; D009593:Nitroimidazoles / Q000494:pharmacology; D010767:Phosphorylcholine / Q000031:analogs & derivatives* / Q000494:pharmacology*; D016019:Survival Analysis; D014349:Trypanosoma cruzi / Q000187:drug effects* / Q000254:growth & development; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D019323:omega-N-Methylarginine / Q000494:pharmacology
chemical_list: D000981:Antiprotozoal Agents; D009593:Nitroimidazoles; D014409:Tumor Necrosis Factor-alpha; D010767:Phosphorylcholine; D019323:omega-N-Methylarginine; D009569:Nitric Oxide; C039128:miltefosine; D019001:Nitric Oxide Synthase; C009999:benzonidazole