Development of a Novel Formulation with Hypericin To Treat Cutaneous Leishmaniasis Based on Photodynamic Therapy inIn VitroandIn VivoStudies

Abstract

An evaluation of the leishmanicidal activity in vitro and in vivo of hypericin, an expanded-spectrum photosensitizer found in Hypericum perforatum, is presented. Hypericin was evaluated against intracellular amastigotes in vitro of Leishmania (Viannia) panamensis. A topical formulation containing 0.5% hypericin was developed and assayed in vivo in a hamster model of cutaneous leishmaniasis. Results demonstrate that hypericin induces a significant antiamastigote effect in vitro against L. panamensis by decreasing the number of parasites inside infected cells. The topical formulation of 0.5% hypericin allows healing of L. panamensis-induced lesions upon a topical application of 40 mg/day plus visible-light irradiation (5 J/cm 2 , 15 min), twice a week for 3 weeks. Cutaneous leishmaniasis (CL) is a parasitic disease caused by protozoa of the genus Leishmania, which manifests as a chronic infection affecting mainly mononuclear phagocytes of the skin (1). The disease affects the poorest populations in 99 countries in tropical and subtropical regions of the world (2, 3). It is estimated that 14 million people are infected, 350 million are at risk, and there are about 1.5 million new cases per year (3, 4). The parasite is transmitted by the bite of an insect vector belonging to the genus Lutzomyia (in America) or Phlebotomus (in Europe, Asia, and Africa) in the subfamily Phlebotominae (5).Only three types of drugs are available to treat CL. They are the pentavalent antimonials (meglumine antimoniate and sodium stibogluconate), pentamidine isethionate, and miltefosine. Miltefosine is the only one available for oral administration (4). These medications are delivered at high doses and for long periods, thus leading to high toxicity. Therefore, their use is contraindicated in pregnant women, in patients with cardiovascular, renal, or hepatic disease, and in children with low body weight (6). Overall, the efficacy of these drugs varies between 55 and 98% depending on the compound and on the Leishmania species causing the clinical manifestation (7,8). However, their elevated toxicity encourages abandonment of treatment and consequently a decrease in the efficacy (9).More recently, photodynamic therapy (PDT) has emerged as an alternative to treat CL (10). This therapy is based on the application of a photosensitizing agent (PA) that, when excited by light of a certain wavelength, induces the production of reactive oxygen species (ROS) that can destroy the microorganism or the target cell (11). In spite of its potential, only a few PAs have been tested against CL in animal models, and only one in humans. Topical application of 5-aminolevulinic acid (ALA) and light in a murine model of CL caused by L. major showed a significant reduction of the parasitic load and the size of lesions (12). Intralesional administration of ALA (one to three PDT sessions) in a patient with CL by L. major produced a 10 to 20% cure, although it is probable that clinical outcome resulted from nonspecific destruction of infected macrophages instead of...

Development of real-time PCR assays for evaluation of immune response and parasite load in golden hamster (Mesocricetus auratus) infected by Leishmania (Viannia) braziliensis

“…Furthermore, its outbred genetic background, which highlights individual characteristics, reproduces the heterogeneity of clinical outcomes observed in human CL [ 11 ]. Nevertheless, few studies on drugs [ 12 – 15 ] and vaccines [ 16 , 17 ] against CL are performed in the hamster model.…”

Aminophthalocyanine-Mediated Photodynamic Inactivation of Leishmania tropica

“…Anti-Leishmania PDT has been assessed experimentally in vivo in different animal models of CL and in vitro in infected macrophages. More recent work includes the use of different photosensitizers, e.g., hypericin, phthalocyanines, phenothiazines, methylene blue, and zinc oxide, as such or after PEGylation or in liposome-/nanoparticle-encapsulated forms, to generate ROS by illumination using different light sources, e.g., light-emitting diodes (LED), lasers, and sunlight (9)(10)(11)(12)(13)(14)(15)(16)(17). The intrinsic susceptibilities of both stages of Leishmania, i.e., promastigotes and amastigotes, to PDT has been examined in that context but rarely has been explored at the cellular and molecular levels.…”

AKT-likekinase promotes cell survival during nutritional stress in trypanosomatids

“…to cause the death of the huMDM, obtained as described in Tirado et al, 2018 [24] while in the HepG2 and CaCo2 cell lines the cytotoxicity was evaluated, by the MTT method (3-(4,5-dimethylthiazol-2-yl) 2,5-diphenyltetrazole) described elsewhere [44,65,66].…”