Nanomedicines for Cutaneous Leishmaniasis

Leishmaniasis is a vector-borne disease caused by Leishmania parasites, which cause a range of clinical manifestations in man. These are didactically classified into cutaneous leishmaniasis (CL), the most common form of the disease, and visceral leishmaniasis (VL), the life-threatening form. There are so far no vaccines approved for humans. Conventional drugs pose limitations ranging from low efficacy and high cost to systemic toxicity. Low efficacy derives in part from difficult drug access to the parasites, which rides themselves inside macrophage phagosomes. This prompts to high dosage, with consequent increased toxicity. Difficult intracellular drug access can be overcome with nanomedicines such as biocompatible lipid and polymeric nanoparticles that can be phagocytosed by the infected macrophages. Besides cell membranes, appropriate drug nanostructuring may allow tissue barrier penetration and drug administration through higher compliance routes such as skin and intestine, in contrast to the usual intravenous and intramuscular routes. In general, CL and VL are both treated with toxic systemic injections, disregard of disease severity. This chapter will review and discuss studies with nanomedicines that have reached the market such as liposomal amphotericin B for intravenous administration, and innovative preclinical studies aiming at developing effective cutaneous and oral drugs with focus on CL

Novel and safe single-dose treatment of cutaneous leishmaniasis with implantable amphotericin B-Loaded microparticles

International audienceThe development of an effective amphotericin B (AmB) topical formulation to replace the systemically toxic injections currently used in cutaneous leishmaniasis (CL) treatment is challenging due to poor absorption through the skin. Aiming at an effective local chemotherapy, we designed PLGA (poly lactide-co-glycolide acid) microspheres loaded with deoxycholate amphotericin B (d-AmB) for both macrophage intracellular targeting and sustained extracellular release. For that, d-AmB/PLGA microspheres with sizes ranging from 0.5 μm to 20 μm were synthesized and tested both in vitro and in vivo. In vitro, d-AmB/PLGA was more selectively active against intracellular amastigotes of Leishmania amazonensis than free d-AmB (selectivity index = 50 and 25, respectively). In vivo, the efficacy of a single intralesional (i.l) injection with d-AmB/PLGA was determined in early and established BALB/c mouse ear lesions. In early lesions, a single injection given on day 10 of infection was more effective in controlling parasite growth than eight i.l. injections with free d-AmB, as measured on day 120. Such d-AmB/PLGA injection was also effective in established lesions (day 30), leading to 97% parasite burden reduction, as compared with d-AmB or liposomal AmB (Ambisome®) i.l. injection containing the same AmB dose. Pharmacokinetic studies showed that following d-AmB/PLGA injection, AmB leaked slower from non-infected than infected ears, yet remaining in the ear tissue for as long as 30 days. Of interest, AmB was not detectable in the circulating plasma for at least two weeks of d-AmB/PLGA injection, contrasting with the rapid and durable (2 days) detection after free d-AmB injection. Despite the transient ear swelling and local cell infiltration, no alterations in AST, ALT and creatinine serum levels was induced by d-AmB/PLGA. For its approved components, local efficacy, and single-dose applicability, this novel and safe AmB microsphere depot formulation has strong potential as a new therapy for human CL

Improved drug loading via spray drying of a chalcone implant for local treatment of cutaneous leishmaniasis

International audienceCurrent chemotherapy of cutaneous leishmaniasis (CL), even the mildest forms, encompasses multiple and painful injections with toxic drugs that cause systemic adverse effects. Recently, we showed the promising use of poly(lactic-co-glycolic acid) (PLGA) microparticles loaded with an antileishmanial nitrosylated chalcone (CH8) for effective, safe, local, and single-dose treatment of CL. Here, we proposed to optimize the delivery system by increasing the CH8 loading in PLGA-microparticles using spray drying instead of emulsification-solvent evaporation. The effect of solvent composition and polymeric matrix changes on thermal properties, loading efficiency, particle size, morphology, and spatial drug distribution of the CH8-loaded microparticles was evaluated. The results showed that spray drying allowed a higher CH8 content (18% w/w), as contrasting with the previous solvent evaporation technique that maximally incorporated 7.8% of CH8. In vitro studies on 96-hour incubation with L. amazonensis-infected macrophages showed that entrapment in spray-dried PLGA microparticles rendered CH8 safer, preserved its antileishmanial activity, and did not affect its antioxidant properties

Composições vacinais contra leishmaniose e usos

Em 15/04/2016: Anuidade de pedido de patente de invenção no prazo ordinárioDepositadaA presente invenção pertence ao campo das composições de vacinas. Mais especificamente, relaciona-se a composições de vacinas para serem administradas por vias de mucosa, incluindo preferencialmente a mucosa oral e nasal. Adicionalmente, a presente invenção abrange ainda o uso das referidas composições

Composições farmacêuticas microparticuladas contendo antiparasitários para terapia subcutânea prolongada, uso das ditas composições farmacêuticas para a produção de um medicamento e método de tratamento de parasitoses

DepositadaA inovação ora proposta se refere a uma composição farmacêutica contendo Anfotericina B, chalcona nitrada (CH8) ou Glucantime encapsulados em micropartículas de polímeros biodegradáveis de liberação lenta, ao processo de encapsulamento do fármaco no interior das partículas; ao uso destas composições farmacêuticas, a um medicamento e ao tratamento de parasitoses

Depot subcutaneous injection with chalcone CH8-loaded Poly (Lactic-Co-Glycilic Acid) microspheres as a single-dose treatment of cutaneous leishmaniasis

International audienceConventional chemotherapy of cutaneous leishmaniasis (CL) is based on multiple parenteral or intralesional injections with systemically toxic drugs. Aiming at a single-dose localized therapy, biodegradable PLGA (poly-(lactide-co-glycolide) microparticles loaded with 7.8% of an antileishmanial nitrochalcone named CH8 (CH8/PLGA) were constructed to promote sustained subcutaneous release. In vitro, murine macrophages avidly phagocytosed CH8/PLGA smaller than 6μm without triggering oxidative mechanisms. Upon 48-hour incubation, both CH8 and CH8/PLGA were 40 times more toxic to intracellular Leishmania amazonensis than to macrophages. In vivo, BALB/c were given one or three subcutaneous injections in the infected ear with 1.2mg/kg of CH8 in free or CH8/PLGA forms, while controls received three CH8-equivalent doses of naked PLGA microparticles or Glucantime. While a single injection with CH8/PLGA reduced the parasite loads by 91%, triple injections with free CH8 or CH8/PLGA caused 80% and 97% reduction, respectively, in relation to saline controls. Glucantime treatment was the least effective (only 36% reduction) and the most toxic as seen by elevated alanine aminotransferase serum levels. Together, those findings show that CH8/PLGA microparticles can be effectively and safely used for single-dose treatment of CL

Antitumoral, antileishmanial and antimalarial activity of pentacyclic 1,4-naphthoquinone derivatives

Pterocarpanquinones 8a-c, previously synthesized in our laboratory, and an homologous series of derivatives, compounds 9a-c prepared in this work, were evaluated on breast cancer cells (MCF-7) and on the parasites Leishmania amazonensis and Plasmodium falciparum, in culture. Compounds 8a-c were more potent than 9a-c on tumor cells and Leishmania amazonensis. On the other hand, 9a-c showed to be more active on Plasmodium falciparum. All the compounds studied were bioselective, presenting negligible cytotoxicity against fresh murine lymphocytes and human lymphocytes activated by the mitogen phytohemaglutinin (PHA)

Use of In Vivo and In Vitro Systems to Select Leishmania amazonensis Expressing Green Fluorescent Protein

Various Leishmania species were engineered with green fluorescent protein (GFP) using episomal vectors that encoded an antibiotic resistance gene, such as aminoglycoside geneticin sulphate (G418). Most reports of GFP-Leishmania have used the flagellated extracellular promastigote, the stage of parasite detected in the midgut of the sandfly vector; fewer studies have been performed with amastigotes, the stage of parasite detected in mammals. In this study, comparisons were made regarding the efficiency for in vitro G418 selection of GFP-Leishmania amazonensis promastigotes and amastigotes and the use of in vivo G418 selection. The GFP-promastigotes retained episomal plasmid for a prolonged period and G418 treatment was necessary and efficient for in vitro selection. In contrast, GFP-amastigotes showed low retention of the episomal plasmid in the absence of G418 selection and low sensitivity to antibiotics in vitro. The use of protocols for G418 selection using infected BALB/c mice also indicated low sensitivity to antibiotics against amastigotes in cutaneous lesions

Intranasal immunization with chitosan microparticles enhances LACK-DNA vaccine protection and induces specific long-lasting immunity against visceral leishmaniasis

Development of a protective vaccine against Leishmania depends on antigen formulation and adjuvants that induce specific immunity and long-lasting immune responses. We previously demonstrated that BALB/c mice intranasally vaccinated with a plasmid DNA encoding the p36/LACK leishmanial antigen (LACK-DNA) develop a protective immunity for up to 3 months after vaccination, which was linked with the systemic expression of vaccine mRNA in peripheral organs. In this study, LACK-DNA vaccine was associated with biocompatible chitosan microparticles cross-linked with glyceraldehyde (CMC) to boost the long-lasting immunity against the late Leishmania infantum challenge. Infection at 7 days, 3 or 6 months after vaccination resulted in significantly lower parasite loads when compared with non-vaccinated controls. Besides, LACK-DNA-chitosan vaccinated mice showed long-time protection observed after the late time point challenge. The achieved protection was correlated with an enhanced spleen cell responsiveness to parasite antigens, marked by increased proliferation and IFN-γ as well as decreased IL-10 production. Moreover, we found diminished systemic levels of TNF-α that was compatible with the better health condition observed in LACK-DNA/CMC vaccinated-infected mice. Together, our data indicate the feasibility of chitosan microparticles as a delivery system tool to extend the protective immunity conferred by LACK-DNA vaccine, which may be explored in vaccine formulations against Leishmania parasite infections