scholarly journals In VitroandIn VivoStudies of the Utility of Dimethyl and Diethyl Carbaporphyrin Ketals in Treatment of Cutaneous Leishmaniasis

2011 ◽  
Vol 55 (10) ◽  
pp. 4755-4764 ◽  
Author(s):  
Viviana M. Taylor ◽  
David L. Cedeño ◽  
Diana L. Muñoz ◽  
Marjorie A. Jones ◽  
Timothy D. Lash ◽  
...  
Keyword(s):  
Visible Light ◽  
Cutaneous Leishmaniasis ◽  
Peritoneal Macrophages ◽  
Lesion Size ◽  
Content Type ◽  
Content Model ◽  
Parasitic Load ◽  
Micromolar Range

ABSTRACTCarbaporphyrin ketals are porphyrinoid compounds in which a pyrrole ring of a typical porphyrin macrocycle has been replaced by a ketal-substituted indene ring. It was recently demonstrated that these compounds are effectivein vitroagainstLeishmania tarentolae. Theirin vitroeffectiveness is increased when they are exposed to visible light; they act as photosensitizers capable of mediating the production of reactive oxygen species (ROS). Following on this evidence, the effectiveness and cytotoxicity of the dimethyl and diethyl carbaporphyrin ketals (CKOMe and CKOEt, respectively) were determinedin vitrousing pathogenicLeishmaniaspecies with and without exposure to visible light (2 and 4 h). The effectiveness against various pathogenicLeishmaniaspecies was determined to be in a micromolar range. Additionally, the effect of encapsulating the carbaporphyrin ketals in liposome formulations was tested. Liposomal delivery diminished their toxicity, while the effectiveness was enhanced upon exposure to visible light (photodynamic effect). The cytotoxicity levels for human U937 cells and hamster peritoneal macrophages were in the ranges of 0.3 to 9 μM and 7 to 330 μM, respectively. When testedin vivo, using a hamster (Mesocricetus auratus) model of cutaneous leishmaniasis, CKOMe was active even in the dark, suggesting that the compound, once metabolized in the animal tissue, produces an active ingredient that does not seem to be photosensitive. Reduction in lesion size, histopathologic analyses, and smears confirmed thein vivo effectiveness of the compound, since the parasitic load was diminished without noticeable toxic effects.

scholarly journals Topical Treatment for Cutaneous Leishmaniasis: Dermato-Pharmacokinetic Lead Optimization of Benzoxaboroles

2018 ◽  
Vol 62 (5) ◽  
Author(s):  
Katrien Van Bocxlaer ◽  
Eric Gaukel ◽  
Deirdre Hauser ◽  
Seong Hee Park ◽  
Sara Schock ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Leishmania Major ◽  
Skin Permeation ◽  
Mouse Skin ◽  
Topical Administration ◽  
Lesion Size ◽  
Drug Formulation ◽  
Content Type

ABSTRACTCutaneous leishmaniasis (CL) is caused by several species of the protozoan parasiteLeishmania, affecting an estimated 10 million people worldwide. Previously reported strategies for the development of topical CL treatments have focused primarily on drug permeation and formulation optimization as the means to increase treatment efficacy. Our approach aims to identify compounds with antileishmanial activity and properties consistent with topical administration. Of the test compounds, five benzoxaboroles showed potent activity (50% effective concentration [EC50] < 5 μM) against intracellular amastigotes of at least oneLeishmaniaspecies and acceptable activity (20 μM < EC50< 30 μM) against two more species. Benzoxaborole compounds were further prioritized on the basis of thein vitroevaluation of progression criteria related to skin permeation, such as the partition coefficient and solubility. An MDCKII-hMDR1 cell assay showed overall good permeability and no significant interaction with the P-glycoprotein transporter for all substrates except LSH002 and LSH031. The benzoxaboroles were degraded, to some extent, by skin enzymes but had stability superior to that ofpara-hydroxybenzoate compounds, which are known skin esterase substrates. Evaluation of permeation through reconstructed human epidermis showed LSH002 to be the most permeant, followed by LSH003 and LSH001. Skin disposition studies following finite drug formulation application to mouse skin demonstrated the highest permeation for LSH001, followed by LSH003 and LSH002, with a significantly larger amount of LSH001 than the other compounds being retained in skin. Finally, the efficacy of the leads (LSH001, LSH002, and LSH003) againstLeishmania majorwas testedin vivo. LSH001 suppressed lesion growth upon topical application, and LSH003 reduced the lesion size following oral administration.

scholarly journals Zinc(II)-Dipicolylamine Coordination Complexes as Targeting and Chemotherapeutic Agents for Leishmania major

2016 ◽  
Vol 60 (5) ◽  
pp. 2932-2940 ◽  
Author(s):  
Douglas R. Rice ◽  
Paola Vacchina ◽  
Brianna Norris-Mullins ◽  
Miguel A. Morales ◽  
Bradley D. Smith
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Mammalian Cells ◽  
Leishmania Major ◽  
Parasite Burden ◽  
Coordination Complexes ◽  
Chemotherapeutic Agents ◽  
Selective Toxicity ◽  
Content Type

ABSTRACTCutaneous leishmaniasis is a neglected tropical disease that causes painful lesions and severe disfigurement. Modern treatment relies on a few chemotherapeutics with serious limitations, and there is a need for more effective alternatives. This study describes the selective targeting of zinc(II)-dipicolylamine (ZnDPA) coordination complexes towardLeishmania major, one of the species responsible for cutaneous leishmaniasis. Fluorescence microscopy ofL. majorpromastigotes treated with a fluorescently labeled ZnDPA probe indicated rapid accumulation of the probe within the axenic promastigote cytosol. The antileishmanial activities of eight ZnDPA complexes were measured using anin vitroassay. All tested complexes exhibited selective toxicity againstL. majoraxenic promastigotes, with 50% effective concentration values in the range of 12.7 to 0.3 μM. Similar toxicity was observed against intracellular amastigotes, but there was almost no effect on the viability of mammalian cells, including mouse peritoneal macrophages.In vivotreatment efficacy studies used fluorescence imaging to noninvasively monitor changes in the red fluorescence produced by an infection of mCherry-L. majorin a mouse model. A ZnDPA treatment regimen reduced the parasite burden nearly as well as the reference care agent, potassium antimony(III) tartrate, and with less necrosis in the local host tissue. The results demonstrate that ZnDPA coordination complexes are a promising new class of antileishmanial agents with potential for clinical translation.

scholarly journals Evaluation of 4-Amino 2-Anilinoquinazolines against Plasmodium and Other Apicomplexan Parasites In Vitro and in a P. falciparum Humanized NOD-scid IL2Rγnull Mouse Model of Malaria

2018 ◽  
Vol 63 (3) ◽  
Author(s):  
Paul R. Gilson ◽  
William Nguyen ◽  
William A. Poole ◽  
Jose E. Teixeira ◽  
Jennifer K. Thompson ◽  
...  
Keyword(s):  
Mouse Model ◽  
Babesia Bovis ◽  
Parasite Line ◽  
Humanized Mouse ◽  
Humanized Mouse Model ◽  
Content Type ◽  
Apicomplexan Parasites ◽  
Micromolar Range

ABSTRACT A series of 4-amino 2-anilinoquinazolines optimized for activity against the most lethal malaria parasite of humans, Plasmodium falciparum, was evaluated for activity against other human Plasmodium parasites and related apicomplexans that infect humans and animals. Four of the most promising compounds from the 4-amino 2-anilinoquinazoline series were equally as effective against the asexual blood stages of the zoonotic P. knowlesi, suggesting that they could also be effective against the closely related P. vivax, another important human pathogen. The 2-anilinoquinazoline compounds were also potent against an array of P. falciparum parasites resistant to clinically available antimalarial compounds, although slightly less so than against the drug-sensitive 3D7 parasite line. The apicomplexan parasites Toxoplasma gondii, Babesia bovis, and Cryptosporidium parvum were less sensitive to the 2-anilinoquinazoline series with a 50% effective concentration generally in the low micromolar range, suggesting that the yet to be discovered target of these compounds is absent or highly divergent in non-Plasmodium parasites. The 2-anilinoquinazoline compounds act as rapidly as chloroquine in vitro and when tested in rodents displayed a half-life that contributed to the compound’s capacity to clear P. falciparum blood stages in a humanized mouse model. At a dose of 50 mg/kg of body weight, adverse effects to the humanized mice were noted, and evaluation against a panel of experimental high-risk off targets indicated some potential off-target activity. Further optimization of the 2-anilinoquinazoline antimalarial class will concentrate on improving in vivo efficacy and addressing adverse risk.

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

2015 ◽  
Vol 59 (9) ◽  
pp. 5804-5813 ◽  
Author(s):  
Andrés Montoya ◽  
Alejandro Daza ◽  
Diana Muñoz ◽  
Karina Ríos ◽  
Viviana Taylor ◽  
...  
Keyword(s):  
Photodynamic Therapy ◽  
Cutaneous Leishmaniasis ◽  
Hypericum Perforatum ◽  
Topical Formulation ◽  
Hamster Model ◽  
Content Type ◽  
Intracellular Amastigotes ◽  
Infected Cells

ABSTRACTAn evaluation of the leishmanicidal activityin vitroandin vivoof hypericin, an expanded-spectrum photosensitizer found inHypericum perforatum, is presented. Hypericin was evaluated against intracellular amastigotesin vitroofLeishmania(Viannia)panamensis. A topical formulation containing 0.5% hypericin was developed and assayedin vivoin a hamster model of cutaneous leishmaniasis. Results demonstrate that hypericin induces a significant antiamastigote effectin vitroagainstL. panamensisby decreasing the number of parasites inside infected cells. The topical formulation of 0.5% hypericin allows healing ofL. panamensis-induced lesions upon a topical application of 40 mg/day plus visible-light irradiation (5 J/cm2, 15 min), twice a week for 3 weeks.

scholarly journals Biological Cost of Different Mechanisms of Colistin Resistance and Their Impact on Virulence in Acinetobacter baumannii

2013 ◽  
Vol 58 (1) ◽  
pp. 518-526 ◽  
Author(s):  
Alejandro Beceiro ◽  
Antonio Moreno ◽  
Nathalie Fernández ◽  
Juán A. Vallejo ◽  
Jesús Aranda ◽  
...  
Keyword(s):  
Growth Rate ◽  
Acinetobacter Baumannii ◽  
Competitive Growth ◽  
Colistin Resistance ◽  
Content Type ◽  
C Elegans ◽  
Content Model ◽  
Mouse Infection

ABSTRACTTwo mechanisms of resistance to colistin have been described inAcinetobacter baumannii. One involves complete loss of lipopolysaccharide (LPS), resulting from mutations inlpxA,lpxC, orlpxD, and the second is associated with phosphoethanolamine addition to LPS, mediated through mutations inpmrAB. In order to assess the clinical impacts of both resistance mechanisms,A. baumanniiATCC 19606 and its isogenic derivatives, AL1851 ΔlpxA, AL1852 ΔlpxD, AL1842 ΔlpxC, and ATCC 19606pmrB, were analyzed forin vitrogrowth rate,in vitroandin vivocompetitive growth, infection of A549 respiratory alveolar epithelial cells, virulence in theCaenorhabditis elegansmodel, and virulence in a systemic mouse infection model. Thein vitrogrowth rate of thelpxmutants was clearly diminished; furthermore,in vitroandin vivocompetitive-growth experiments revealed a reduction in fitness for both mutant types. Infection of A549 cells with ATCC 19606 or thepmrBmutant resulted in greater loss of viability than withlpxmutants. Finally, thelpxmutants were highly attenuated in both theC. elegansand mouse infection models, while thepmrBmutant was attenuated only in theC. elegansmodel. In summary, while colistin resistance inA. baumanniiconfers a clear selective advantage in the presence of colistin treatment, it causes a noticeable cost in terms of overall fitness and virulence, with a more striking reduction associated with LPS loss than with phosphoethanolamine addition. Therefore, we hypothesize that colistin resistance mediated by changes inpmrABwill be more likely to arise in clinical settings in patients treated with colistin.

scholarly journals Efficacy of a Binuclear Cyclopalladated Compound Therapy for Cutaneous Leishmaniasis in the Murine Model of Infection with Leishmania amazonensis and Its Inhibitory Effect on Topoisomerase 1B

2017 ◽  
Vol 61 (8) ◽  
Author(s):  
Angela Maria Arenas Velásquez ◽  
Willian Campos Ribeiro ◽  
Vutey Venn ◽  
Silvia Castelli ◽  
Mariana Santoro de Camargo ◽  
...  
Keyword(s):  
Leishmania Donovani ◽  
Parasite Load ◽  
Inhibitory Effect ◽  
Peritoneal Macrophages ◽  
Leishmania Amazonensis ◽  
Content Type ◽  
Intracellular Amastigotes ◽  
Therapeutic Alternatives

ABSTRACT Leishmaniasis is a disease found throughout the (sub)tropical parts of the world caused by protozoan parasites of the Leishmania genus. Despite the numerous problems associated with existing treatments, pharmaceutical companies continue to neglect the development of better ones. The high toxicity of current drugs combined with emerging resistance makes the discovery of new therapeutic alternatives urgent. We report here the evaluation of a binuclear cyclopalladated complex containing Pd(II) and N,N′-dimethylbenzylamine (Hdmba) against Leishmania amazonensis. The compound [Pd(dmba)(μ-N3)]2 (CP2) inhibits promastigote growth (50% inhibitory concentration [IC50] = 13.2 ± 0.7 μM) and decreases the proliferation of intracellular amastigotes in in vitro incubated macrophages (IC50 = 10.2 ± 2.2 μM) without a cytotoxic effect when tested against peritoneal macrophages (50% cytotoxic concentration = 506.0 ± 10.7 μM). In addition, CP2 was also active against T. cruzi intracellular amastigotes (IC50 = 2.3 ± 0.5 μM, selective index = 225), an indication of its potential for use in Chagas disease therapy. In vivo assays using L. amazonensis-infected BALB/c showed an 80% reduction in parasite load compared to infected and nontreated animals. Also, compared to amphotericin B treatment, CP2 did not show any side effects, which was corroborated by the analysis of plasma levels of different hepatic and renal biomarkers. Furthermore, CP2 was able to inhibit Leishmania donovani topoisomerase 1B (Ldtopo1B), a potentially important target in this parasite. (This study has been registered at ClinicalTrials.gov under identifier NCT02169141.)

scholarly journals Development of anEx VivoLymph Node Explant Model for Identification of Novel Molecules Active against Leishmania major

2013 ◽  
Vol 58 (1) ◽  
pp. 78-87 ◽  
Author(s):  
Alex G. Peniche ◽  
Yaneth Osorio ◽  
Adam R. Renslo ◽  
Doug E. Frantz ◽  
Peter C. Melby ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Leishmania Major ◽  
Drug Efficacy ◽  
Peritoneal Macrophages ◽  
Effective Concentration ◽  
Content Type ◽  
Drug Candidates ◽  
New Drug ◽  
Vector Borne

ABSTRACTLeishmaniasis is a vector-borne zoonotic infection affecting people in tropical and subtropical regions of the world. Current treatments for cutaneous leishmaniasis are difficult to administer, toxic, expensive, and limited in effectiveness and availability. Here we describe the development and application of a medium-throughput screening approach to identify new drug candidates for cutaneous leishmaniasis using anex vivolymph nodeexplantculture (ELEC) derived from the draining lymph nodes ofLeishmania major-infected mice. The ELEC supported intracellular amastigote proliferation and contained lymph node cell populations (and their secreted products) that enabled the testing of compounds within a system that mimicked the immunopathological environment of the infected host, which is known to profoundly influence parasite replication, killing, and drug efficacy. The activity of known antileishmanial drugs in the ELEC system was similar to the activity measured in peritoneal macrophages infectedin vitrowithL. major. Using the ELEC system, we screened a collection of 334 compounds, some of which we had demonstrated previously to be active againstL. donovani, and identified 119 hits, 85% of which were confirmed to be active by determination of the 50% effective concentration (EC50). We found 24 compounds (7%) that had aninvitrotherapeuticindex (IVTI; 50% cytotoxic/effective concentration [CC50]/EC50) > 100; 19 of the compounds had an EC50below 1 μM. According to PubChem searchs, 17 of those compounds had not previously been reported to be active againstLeishmania. We expect that this novel method will help to accelerate discovery of new drug candidates for treatment of cutaneous leishmaniasis.

scholarly journals Depot Subcutaneous Injection with Chalcone CH8-Loaded Poly(Lactic-Co-Glycolic Acid) Microspheres as a Single-Dose Treatment of Cutaneous Leishmaniasis

2017 ◽  
Vol 62 (3) ◽  
Author(s):  
Ariane de Jesus Sousa-Batista ◽  
Wallace Pacienza-Lima ◽  
Natalia Arruda-Costa ◽  
Camila Alves Bandeira Falcão ◽  
Maria Ines Ré ◽  
...  
Keyword(s):  
Single Dose ◽  
Cutaneous Leishmaniasis ◽  
Glycolic Acid ◽  
Content Type ◽  
Dose Treatment ◽  
Meglumine Antimoniate ◽  
Plga Microparticles ◽  
Single Dose Treatment

ABSTRACTConventional 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 poly(lactic-co-glycolic acid) (PLGA) 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 6 μm without triggering oxidative mechanisms. Upon 48 h of incubation, both CH8 and CH8/PLGA were 40 times more toxic to intracellularLeishmania amazonensisthan to macrophages.In vivo, BALB/c were given one or three subcutaneous injections in the infected ear with 1.2 mg/kg of CH8 in free or CH8/PLGA forms, whereas controls received three CH8-equivalent doses of naked PLGA microparticles or meglumine antimoniate (Glucantime; Sanofi-Aventis). Although a single injection with CH8/PLGA reduced the parasite loads by 91%, triple injections with free CH8 or CH8/PLGA caused 80 and 97% reductions, respectively, in relation to saline controls. Meglumine antimoniate treatment was the least effective (only 36% reduction) and the most toxic, as indicated by elevated alanine aminotransferase serum levels. Together, these findings show that CH8/PLGA microparticles can be effectively and safely used for single-dose treatment of CL.

scholarly journals In Vitro and In Vivo Evaluation of an Adamantyl-Based Phenyl Sulfonyl Acetamide against Cutaneous Leishmaniasis Models of Leishmania amazonensis

2020 ◽  
Vol 64 (12) ◽  
Author(s):  
Camila C. Santos ◽  
Huaisheng Zhang ◽  
Marcos M. Batista ◽  
Gabriel M. de Oliveira ◽  
Kelly C. Demarque ◽  
...  
Keyword(s):  
Cutaneous Leishmaniasis ◽  
Parasite Load ◽  
Leishmania Amazonensis ◽  
Host Cells ◽  
In Vivo Evaluation ◽  
Content Type ◽  
Suboptimal Dose ◽  
Low Toxicity

ABSTRACT Phenotypic assay against Leishmania amazonensis in vitro and in vivo led to identification of an adamantyl-based phenyl sulfonyl acetamide (compound 1) as a promising antileishmanial agent. Compound 1 inhibited the growth of intracellular forms of L. amazonensis (50% inhibitory concentration [IC50] = 4 μM) and exhibited low toxicity to host cells, with a selectivity index (SI) of >125. However, in a cutaneous leishmaniasis (CL) mouse model, compound 1 did not reduce lesions and parasite load when administered as monotherapy or when given simultaneously with a suboptimal dose of miltefosine.

scholarly journals Efficacy of Paromomycin-Chloroquine Combination Therapy in Experimental Cutaneous Leishmaniasis

2017 ◽  
Vol 61 (8) ◽  
Author(s):  
Gert-Jan Wijnant ◽  
Katrien Van Bocxlaer ◽  
Vanessa Yardley ◽  
Sudaxshina Murdan ◽  
Simon L. Croft
Keyword(s):  
Combination Therapy ◽  
Cutaneous Leishmaniasis ◽  
Leishmania Major ◽  
Q Fever ◽  
Parasite Load ◽  
Potential Candidate ◽  
Preclinical Development ◽  
Content Type

ABSTRACT The 4-aminoquinoline chloroquine (CQ) is clinically used in combination with doxycycline to cure chronic Q fever, as it enhances the activity of the antibiotic against the causative bacterium Coxiella burnetii residing within macrophage phagolysosomes. As there is a similar cellular host-pathogen biology for Leishmania parasites, this study aimed to determine whether such an approach could also be the basis for a new, improved treatment for cutaneous leishmaniasis (CL). We have evaluated the in vitro and in vivo activities of combinations of CQ with the standard drugs paromomycin (PM), miltefosine, and amphotericin B against Leishmania major and Leishmania mexicana. In 72-h intracellular antileishmanial assays, outcomes were variable for different drugs. Significantly, the addition of 10 μM CQ to PM reduced 50% effective concentrations (EC50s) by over 5-fold against L. major and against normally insensitive L. mexicana parasites. In murine models of L. major and L. mexicana CL, daily coadministration of 50 mg/kg of body weight PM and 25 mg/kg CQ for 10 days resulted in a significant reduction in lesion size but not in parasite load compared to those for mice given the same doses of PM alone. Overall, our data indicate that PM-CQ combination therapy is unlikely to be a potential candidate for further preclinical development.

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