Borborema Samanta Etel Treiger, Osso Junior João Alberto, Andrade Junior Heitor Franco de, Nascimento Nanci do
Centro de Biotecnologia, Instituto de Pesquisas Energéticas e Nucleares, São Paulo, São Paulo, Brazil.
Centro de Radiofarmácia, Instituto de Pesquisas Energéticas e Nucleares, São Paulo, São Paulo, Brazil.
Rev Soc Bras Med Trop. 2016 Apr;49(2):196-203. doi: 10.1590/0037-8682-0041-2016.
Leishmaniasis is a disease caused by the protozoan Leishmania that resides mainly in mononuclear phagocytic system tissues. Pentavalent antimonials are the main treatment option, although these drugs have toxic side effects and high resistance rates. A potentially alternative and more effective therapeutic strategy is to use liposomes as carriers of the antileishmanial agents. The aims of this study were to develop antimonial drugs entrapped into phosphatidylserine liposomes and to analyze their biological and physicochemical characteristics.
Liposomes containing meglumine antimoniate (MA) or pentavalent antimony salt (Sb) were obtained through filter extrusion (FEL) and characterized by transmission electron microscopy. Promastigotes of Leishmania infantum were incubated with the drugs and the viability was determined with a tetrazolium dye (MTT assay). The effects of these drugs against intracellular amastigotes were also evaluated by optical microscopy, and mammalian cytotoxicity was determined by an MTT assay.
Liposomes had an average diameter of 162nm. MA-FEL showed inhibitory activity against intracellular L. infantum amastigotes, with a 50% inhibitory concentration (IC50) of 0.9μg/mL, whereas that of MA was 60μg/mL. Sb-FEL showed an IC50 value of 0.2μg/mL, whereas that of free Sb was 9μg/mL. MA-FEL and Sb-FEL had strong in vitro activity that was 63-fold and 39-fold more effective than their respective free drugs. MA-FEL tested at a ten-times higher concentration than Sb-FEL did not show cytotoxicity to mammalian cells, resulting in a higher selectivity index.
Antimonial drug-containing liposomes are more effective against Leishmania-infected macrophages than the non-liposomal drugs.
利什曼病是一种由原生动物利什曼原虫引起的疾病，主要寄生于单核吞噬细胞系统组织中。五价锑化合物是主要的治疗选择，尽管这些药物具有毒副作用且耐药率高。一种潜在的替代且更有效的治疗策略是使用脂质体作为抗利什曼药物的载体。本研究的目的是开发包封于磷脂酰丝氨酸脂质体中的锑化合物药物，并分析其生物学和物理化学特性。
通过滤膜挤压法（FEL）制备含葡甲胺锑酸盐（MA）或五价锑盐（Sb）的脂质体，并用透射电子显微镜对其进行表征。将婴儿利什曼原虫前鞭毛体与药物孵育，用四唑盐染料（MTT法）测定其活力。通过光学显微镜评估这些药物对细胞内无鞭毛体的作用，并通过MTT法测定其对哺乳动物细胞的毒性。
脂质体的平均直径为162nm。MA-FEL对细胞内婴儿利什曼原虫无鞭毛体显示出抑制活性，其50%抑制浓度（IC50）为0.9μg/mL，而MA的IC50为60μg/mL。Sb-FEL的IC50值为0.2μg/mL，而游离Sb的IC50为9μg/mL。MA-FEL和Sb-FEL具有很强的体外活性，分别比各自的游离药物有效63倍和39倍。MA-FEL在比Sb-FEL高10倍的浓度下进行测试，未显示出对哺乳动物细胞的细胞毒性，从而产生了更高的选择性指数。
含锑化合物药物的脂质体对感染利什曼原虫的巨噬细胞比非脂质体药物更有效。
