Search

African trypanosomiasis is a deadly neglected disease caused by the extracellular parasite Trypanosoma brucei. Current therapies are characterized by high drug toxicity and increasing drug resistance mainly associated with loss-of-function mutations in the transporters involved in drug import. The introduction of new antiparasitic drugs into therapeutic use is a slow and expensive process. In contrast, specific targeting of existing drugs could represent a more rapid and cost-effective approach for neglected disease treatment, impacting through reduced systemic toxicity and circumventing resistance acquired through impaired compound uptake. We have generated nanoparticles of chitosan loaded with the trypanocidal drug pentamidine and coated by a single domain nanobody that specifically targets the surface of African trypanosomes. Once loaded into this nanocarrier, pentamidine enters trypanosomes through endocytosis instead of via classical cell surface transporters. The curative dose of pentamidine-loaded nanobody-chitosan nanoparticles was 100-fold lower than pentamidine alone in a murine model of acute African trypanosomiasis. Crucially, this new formulation displayed undiminished in vitro and in vivo activity against a trypanosome cell line resistant to pentamidine as a result of mutations in the surface transporter aquaglyceroporin 2. We conclude that this new drug delivery system increases drug efficacy and has the ability to overcome resistance to some anti-protozoal drugs., Author Summary Drug resistance is complicating the treatment of parasitic diseases including African trypanosomiasis, a fatal disease if left untreated. Development of a vaccine is unlikely due to parasite antigenic variation. Current chemotherapy relies primarily on four drugs. Three of these drugs access the cell’s interior through surface transporters and resistance mechanisms are largely associated with loss-of-function mutations in the involved surface drug transporters. We reasoned that using an alternative drug entrance would circumvent parasite resistance due to mutation in a surface transporter. We have developed a drug nanocarrier that consists of polymeric nanoparticles coated with a single domain antibody that targets the trypanosome surface. This new formulation reduces the minimal curative dose and, most importantly, circumvents drug resistance in a resistant cell line as a result of mutations in the surface transporter that mediate drug uptake. This study presents a proof-of-concept of a novel technology for reversing transporter-related drug resistance with applications to other infectious diseases.

Anovel one-pot synthesis of tri-substituted purines and the discovery of purine analogues with trypanocidal activity are reported. The reaction is initiated by a metal-free oxidative coupling of primary alkoxides and diaminopyrimidines with Schiff base formation and subsequent annulation in the presence of large N,N-dimethylamides (e.g.N,N-dimethylpropanamide or larger). This synthetic route is in competition with a reaction previously-reported by our group1, allowing the generation of a combinatorial library of tri-substituted purines by the simple modification of the amide and the alkoxide employed. Among the variety of structures generated, two purine analogues displayed trypanocidal activity against the protozoan parasite Trypanosoma brucei with IC50 , 5 mM, being each of those compounds obtained through each of the synthetic pathways., J.J.D.M. thanks Spanish Ministerio de Economı´a y Competitividad for a Ramon y Cajal Fellowship. A.U.B. thanks MRC IGMM for an academic fellowship. This work was partially supported by Grant SAF2011-30528 to J.A.G.S..

Estudo da ação dos Tripanocidas para o tratamento da doença do sono em missões de combate à tripanossomíase realizadas em Tete (Moçambique) concluindo-se que quer o Antripol quer a Pentamidina são excelentes tripanocidas periféricos com valor terapêutico semelhante. info:eu-repo/semantics/publishedVersion