scholarly journals Antileishmanial Activity, Uptake, and Biodistribution of an Amphotericin B and Poly(α-Glutamic Acid) Complex

2013 ◽  
Vol 57 (10) ◽  
pp. 4608-4614 ◽  
Author(s):  
Abeer H. A. Mohamed-Ahmed ◽  
Karin Seifert ◽  
Vanessa Yardley ◽  
Hollie Burrell-Saward ◽  
Stephen Brocchini ◽  
...  
Keyword(s):  
Glutamic Acid ◽  
Amphotericin B ◽  
Leishmania Donovani ◽  
Water Soluble ◽  
Molecular Weight Range ◽  
Acid Complex ◽  
Content Type ◽  
New Treatment

ABSTRACTA noncovalent, water-soluble complex of amphotericin B (AMB) and poly(α-glutamic acid) (PGA), with AMB loadings ranging from 25 to 55% (wt/wt) using PGA with a molecular weight range of 50,000 to 70,000, was prepared as a potential new treatment for visceral leishmaniasis (VL). The AMB-PGA complex was shown to be as active as Fungizone (AMB deoxycholate) against intracellularLeishmania donovaniamastigotes in differentiated THP-1 cells. Thein vitrouptake of the AMB-PGA complex by differentiated THP-1 cells was similar to that of Fungizone and higher than that of AmBisome (liposomal AMB). The AMB-PGA complex also displayed a dose-response profile similar to that of AmBisomein vivoin BALB/c mice againstL. donovani, with 50% effective doses (ED50s) of 0.24 ± 0.03 mg/kg of body weight for the AMB-PGA complex and 0.24 ± 0.06 mg/kg for AmBisome. A biodistribution study with mice indicated that the AMB-PGA complex cleared more rapidly from plasma than AmBisome, with a comparable low level of distribution to the kidneys.

scholarly journals Antileishmanial Efficacy and Pharmacokinetics of DB766-Azole Combinations

2017 ◽  
Vol 62 (1) ◽  
Author(s):  
April C. Joice ◽  
Sihyung Yang ◽  
Abdelbasset A. Farahat ◽  
Heidi Meeds ◽  
Mei Feng ◽  
...  
Keyword(s):  
Visceral Leishmaniasis ◽  
Leishmania Donovani ◽  
Treatment Strategies ◽  
Parasite Burden ◽  
Pharmacokinetic Analysis ◽  
Content Type ◽  
New Treatment ◽  
Almost All

ABSTRACT Given the limitations of current antileishmanial drugs and the utility of oral combination therapy for other infections, developing an oral combination against visceral leishmaniasis should be a high priority. In vitro combination studies with DB766 and antifungal azoles against intracellular Leishmania donovani showed that posaconazole and ketoconazole, but not fluconazole, enhanced DB766 potency. Pharmacokinetic analysis of DB766-azole combinations in uninfected Swiss Webster mice revealed that DB766 exposure was increased by higher posaconazole and ketoconazole doses, while DB766 decreased ketoconazole exposure. In L. donovani-infected BALB/c mice, DB766-posaconazole combinations given orally for 5 days were more effective than DB766 or posaconazole alone. For example, 81% ± 1% (means ± standard errors) inhibition of liver parasite burden was observed for 37.5 mg/kg of body weight DB766 plus 15 mg/kg posaconazole, while 37.5 mg/kg DB766 and 15 mg/kg posaconazole administered as monotherapy gave 40% ± 5% and 21% ± 3% inhibition, respectively. Combination index (CI) analysis indicated that synergy or moderate synergy was observed in six of nine combined dose groups, while the other three were nearly additive. Liver concentrations of DB766 and posaconazole increased in almost all combination groups compared to monotherapy groups, although many increases were not statistically significant. For DB766-ketoconazole combinations evaluated in this model, two were antagonistic, one displayed synergy, and one was nearly additive. These data indicate that the efficacy of DB766-posaconazole and DB766-ketoconazole combinations in vivo is influenced in part by the pharmacokinetics of the combination, and that the former combination deserves further consideration in developing new treatment strategies against visceral leishmaniasis.

scholarly journals Immunoadjuvant Chemotherapy of Visceral Leishmaniasis in Hamsters Using Amphotericin B-Encapsulated Nanoemulsion Template-Based Chitosan Nanocapsules

2013 ◽  
Vol 57 (4) ◽  
pp. 1714-1722 ◽  
Author(s):  
Shalini Asthana ◽  
Anil K. Jaiswal ◽  
Pramod K. Gupta ◽  
Vivek K. Pawar ◽  
Anuradha Dube ◽  
...  
Keyword(s):  
Visceral Leishmaniasis ◽  
Amphotericin B ◽  
Leishmania Donovani ◽  
Transforming Growth Factor ◽  
Treatment Options ◽  
Interleukin 12 ◽  
Necrosis Factor Alpha ◽  
Content Type

ABSTRACTThe accessible treatment options for life-threatening neglected visceral leishmaniasis (VL) disease have problems with efficacy, stability, adverse effects, and cost, making treatment a complex issue. Here we formulated nanometric amphotericin B (AmB)-encapsulated chitosan nanocapsules (CNC-AmB) using a polymer deposition technique mediated by nanoemulsion template fabrication. CNC-AmB exhibited good steric stabilityin vitro, where the chitosan content was found to be efficient at preventing destabilization in the presence of protein and Ca2+. A toxicity study on the model cell line J774A and erythrocytes revealed that CNC-AmB was less toxic than commercialized AmB formulations such as Fungizone and AmBisome. The results ofin vitro(macrophage-amastigote system; 50% inhibitory concentration [IC50], 0.19 ± 0.04 μg AmB/ml) andin vivo(Leishmania donovani-infected hamsters; 86.1% ± 2.08% parasite inhibition) experiments in conjunction with effective internalization by macrophages illustrated the efficacy of CNC-AmB at augmenting antileishmanial properties. Quantitative mRNA analysis by real-time PCR (RT-PCR) showed that the improved effect was synergized with the upregulation of tumor necrosis factor alpha (TNF-α), interleukin-12 (IL-12), and inducible nitric oxide synthase and with the downregulation of transforming growth factor β (TGF-β), IL-10, and IL-4. These research findings suggest that a cost-effective CNC-AmB immunoadjuvant chemotherapeutic delivery system could be a viable alternative to the current high-cost commercial lipid-based formulations.

scholarly journals Surface-Engineered Dendrimeric Nanoconjugates for Macrophage-Targeted Delivery of Amphotericin B: Formulation Development andIn VitroandIn VivoEvaluation

2015 ◽  
Vol 59 (5) ◽  
pp. 2479-2487 ◽  
Author(s):  
Keerti Jain ◽  
Ashwni Kumar Verma ◽  
Prabhat Ranjan Mishra ◽  
Narendra Kumar Jain
Keyword(s):  
Drug Release ◽  
Amphotericin B ◽  
Human Erythrocytes ◽  
Antileishmanial Activity ◽  
Cell Uptake ◽  
Antiparasitic Activity ◽  
Content Type ◽  
Drug Localization

ABSTRACTThe present study aimed to develop an optimized dendrimeric delivery system for amphotericin B (AmB). Fifth-generation (5.0G) poly(propylene imine) (PPI) dendrimers were synthesized, conjugated with mannose, and characterized by use of various analytical techniques, including Fourier transform infrared spectroscopy (FTIR),1H nuclear magnetic resonance (1H-NMR) spectroscopic analysis, and atomic force microscopy (AFM). Mannose-conjugated 5.0G PPI (MPPI) dendrimers were loaded with AmB and evaluated for drug loading efficiency,in vitrodrug release profile, stability, hemolytic toxicity to human erythrocytes, cytotoxicity to and cell uptake by J774A.1 macrophage cells, antiparasitic activity against intracellularLeishmania donovaniamastigotes,in vivopharmacokinetic and biodistribution profiles, drug localization index, toxicity, and antileishmanial activity. AFM showed the nanometric size of the MPPI dendrimers, with a nearly globular architecture. The conjugate showed a good entrapment efficiency for AmB, along with pH-sensitive drug release. Highly significant reductions in toxicity toward human erythrocytes and macrophage cells, without compromising the antiparasitic activity of AmB, were observed. The dendrimeric formulation of AmB showed a significant enhancement of the parasiticidal activity of AmB toward intramacrophagicL. donovaniamastigotes. In thein vitrocell uptake studies, the formulation showed selectivity toward macrophages, with significant intracellular uptake. Further pharmacokinetic and organ distribution studies elucidated the controlled delivery behavior of the formulation. The drug localization index was found to increase significantly in macrophage-rich organs.In vivostudies showed a biocompatible behavior of MPPIA, with negligible toxicity even at higher doses, and promising antileishmanial activity. From the results, we concluded that surface-engineered dendrimers may serve as optimized delivery vehicles for AmB with enhanced activity and low or negligible toxicity.

scholarly journals TCP1γ Subunit Is Indispensable for Growth and Infectivity of Leishmania donovani

2020 ◽  
Vol 64 (8) ◽  
Author(s):  
Shailendra Yadav ◽  
Jitendra Kuldeep ◽  
Mohammad I. Siddiqi ◽  
Neena Goyal
Keyword(s):  
Cell Cycle Progression ◽  
Leishmania Donovani ◽  
Gene Replacement ◽  
Titration Calorimetry ◽  
Content Type ◽  
T Complex ◽  
Complex Protein ◽  
Oligomeric Complex

ABSTRACT T-complex protein-1 (TCP1) is a ubiquitous group II chaperonin and is known to fold various proteins, such as actin and tubulin. In Leishmania donovani, the γ subunit of TCP1 (LdTCP1γ) has been cloned and characterized. It forms a high-molecular-weight homo-oligomeric complex that performs ATP-dependent protein folding. In the present study, we evaluated the essentiality of the LdTCP1γ gene. Gene replacement studies indicated that LdTCP1γ is essential for parasite survival. The LdTCP1γ single-allele-replacement mutants exhibited slowed growth and decreased infectivity in mouse macrophages compared to the growth and infectivity of the wild-type parasites. Modulation of LdTCP1γ expression in promastigotes also modulated cell cycle progression. Suramin, an antitrypanosomal drug, not only inhibited the luciferase refolding activity of the recombinant LdTCP1γ (rLdTCP1γ) homo-oligomeric complex but also exhibited potential antileishmanial efficacy both in vitro and in vivo. The interaction of suramin and LdTCP1γ was further validated by isothermal titration calorimetry. The study suggests LdTCP1γ as a potential drug target and also provides a framework for the development of a new class of drugs.

scholarly journals New Triazole NT-a9 Has Potent Antifungal Efficacy against Cryptococcus neoformans In Vitro and In Vivo

2019 ◽  
Vol 64 (2) ◽  
Author(s):  
Ren-Yi Lu ◽  
Ting-Jun-Hong Ni ◽  
Jing Wu ◽  
Lan Yan ◽  
Quan-Zhen Lv ◽  
...  
Keyword(s):  
Cryptococcus Neoformans ◽  
Amphotericin B ◽  
Pathogenic Fungi ◽  
Control Group ◽  
Survival Times ◽  
Content Type ◽  
Fungal Burden ◽  
Wide Range

ABSTRACT In the past decades, the incidence of cryptococcosis has increased dramatically, which poses a new threat to human health. However, only a few drugs are available for the treatment of cryptococcosis. Here, we described a leading compound, NT-a9, an analogue of isavuconazole, that showed strong antifungal activities in vitro and in vivo. NT-a9 showed a wide range of activities against several pathogenic fungi in vitro, including Cryptococcus neoformans, Cryptococcus gattii, Candida albicans, Candida krusei, Candida tropicalis, Candida glabrata, and Candida parapsilosis, with MICs ranging from 0.002 to 1 μg/ml. In particular, NT-a9 exhibited excellent efficacy against C. neoformans, with a MIC as low as 0.002 μg/ml. NT-a9 treatment resulted in changes in the sterol contents in C. neoformans, similarly to fluconazole. In addition, NT-a9 possessed relatively low cytotoxicity and a high selectivity index. The in vivo efficacy of NT-a9 was assessed using a murine disseminated-cryptococcosis model. Mice were infected intravenously with 1.8 × 106 CFU of C. neoformans strain H99. In the survival study, NT-a9 significantly prolonged the survival times of mice compared with the survival times of the control group or the isavuconazole-, fluconazole-, or amphotericin B-treated groups. Of note, 4 and 8 mg/kg of body weight of NT-a9 rescued all the mice, with a survival rate of 100%. In the fungal-burden study, NT-a9 also significantly reduced the fungal burdens in brains and lungs, while fluconazole and amphotericin B only reduced the fungal burden in lungs. Taken together, these data suggested that NT-a9 is a promising antifungal candidate for the treatment of cryptococcosis infection.

scholarly journals In Vitro Evaluation of Radiolabeled Amphotericin B for Molecular Imaging of Mold Infections

2020 ◽  
Vol 64 (7) ◽  
Author(s):  
Lukas Page ◽  
Andrew J. Ullmann ◽  
Fabian Schadt ◽  
Sebastian Wurster ◽  
Samuel Samnick
Keyword(s):  
Molecular Imaging ◽  
Amphotericin B ◽  
Invasive Pulmonary Aspergillosis ◽  
Nuclear Imaging ◽  
Molecular Probes ◽  
Content Type ◽  
Diagnostic Potential ◽  
Gallium 68

ABSTRACT Invasive pulmonary aspergillosis and mucormycosis are life-threatening complications in immunocompromised patients. A rapid diagnosis followed by early antifungal treatment is essential for patient survival. Given the limited spectrum of biomarkers for invasive mold infections, recent studies have proposed the use of radiolabeled siderophores or antibodies as molecular probes to increase the specificity of radiological findings by nuclear imaging modalities. While holding enormous diagnostic potential, most of the currently available molecular probes are tailored to the detection of Aspergillus species, and their cost-intensive and sophisticated implementation restricts their accessibility at less specialized centers. In order to develop cost-efficient and broadly applicable tracers for pulmonary mold infections, this study established streamlined and high-yielding protocols to radiolabel amphotericin B (AMB) with the gamma emitter technetium-99m (99mTc-AMB) and the positron emitter gallium-68 (68Ga-AMB). The radiochemical purity of the resulting tracers consistently exceeded 99%, and both probes displayed excellent stability in human serum (>98% after 60 to 240 min at 37°C). The uptake kinetics by representative mold pathogens were assessed in an in vitro Transwell assay using infected endothelial cell layers. Both tracers accumulated intensively and specifically in Transwell inserts infected with Aspergillus fumigatus, Rhizopus arrhizus, and other clinically relevant mold pathogens compared with their accumulation in uninfected inserts and inserts infected with bacterial controls. Inoculum-dependent enrichment was confirmed by gamma counting and autoradiographic imaging. Taken together, this pilot in vitro study proposes 99mTc-AMB and 68Ga-AMB to be facile, stable, and specific probes, meriting further preclinical in vivo evaluation of radiolabeled amphotericin B for molecular imaging in invasive mycoses.

scholarly journals Novel Role of Calmodulin in Regulating Protein Transport to Mitochondria in a Unicellular Eukaryote

2013 ◽  
Vol 33 (22) ◽  
pp. 4579-4593 ◽  
Author(s):  
Abhishek Aich ◽  
Chandrima Shaha
Keyword(s):  
Leishmania Donovani ◽  
Protein Transport ◽  
Mitochondrial Protein ◽  
Unicellular Eukaryote ◽  
Mitochondrial Targeting ◽  
Content Type ◽  
Mitochondrial Translocation ◽  
Tryparedoxin Peroxidase

Lower eukaryotes like the kinetoplastid parasites are good models to study evolution of cellular pathways during steps to eukaryogenesis. In this study, a kinetoplastid parasite,Leishmania donovani, was used to understand the process of mitochondrial translocation of a nucleus-encoded mitochondrial protein, the mitochondrial tryparedoxin peroxidase (mTXNPx). We report the presence of an N-terminal cleavable mitochondrial targeting signal (MTS) validated through deletion and grafting experiments. We also establish a novel finding of calmodulin (CaM) binding to the MTS of mTXNPx through specific residues. Mutation of CaM binding residues, keeping intact the residues involved in mitochondrial targeting and biochemical inhibition of CaM activity bothin vitroandin vivo, prevented mitochondrial translocation. Through reconstituted import assays, we demonstrate obstruction of mitochondrial translocation either in the absence of CaM or Ca2+or in the presence of CaM inhibitors. We also demonstrate the prevention of temperature-driven mTXNPx aggregation in the presence of CaM. These findings establish the idea that CaM is required for the transport of the protein to mitochondria through maintenance of translocation competence posttranslation.

scholarly journals Efficacious Treatment of Experimental Leishmaniasis with Amphotericin B-Arabinogalactan Water-Soluble Derivatives

1999 ◽  
Vol 43 (9) ◽  
pp. 2209-2214 ◽  
Author(s):  
Jacob Golenser ◽  
Shoshana Frankenburg ◽  
Tirtsa Ehrenfreund ◽  
Abraham J. Domb
Keyword(s):  
Amphotericin B ◽  
Leishmania Major ◽  
Water Soluble ◽  
In Vivo Experiments ◽  
Drug Concentrations ◽  
Efficacious Treatment ◽  
Lipid Formulations ◽  
Established Infection

ABSTRACT In this study, we tested the efficacy of amphotericin B (AmB)-arabinogalactan (AmB-AG) conjugates for the treatment of experimental leishmaniasis. Chemical conjugation of AmB to a water-soluble, biodegradable, and biocompatible polymer could present many advantages over presently available AmB formulations. Two conjugates were tested, a reduced (rAmB-AG) form and an unreduced (uAmB-AG) form. In vitro, the drug concentrations which lower the values of parasites (for promastigotes) or infected macrophages (for amastigotes) to 50% of the untreated values (ED50s) of uAmB-AG and rAmB-AG were 0.19 and 0.34 μg/ml, respectively, forLeishmania major promastigotes and 0.17 and 0.31 μg/ml, respectively, for amastigotes. The effect on Leishmania infantum-infected macrophages was more marked, with ED50s of 0.035 μg/ml for rAmB-AG and 0.027 μg/ml for uAmB-AG. In in vivo experiments, BALB/c mice injected with L. major were treated from day 2 onwards on alternate days for 2 weeks. Both conjugates, as well as liposomal AmB (all at 6 mg/kg of body weight) and Fungizone (1 mg/kg), significantly delayed the appearance of lesions compared to that in untreated mice. In addition, both conjugates, but not liposomal AmB, were significantly more effective than Fungizone. Subcutaneous injection of the conjugates (6 mg/kg) was significantly more effective than liposomal AmB in delaying the appearance of lesions. Higher AmB concentrations of up to 12 mg/kg could be administered by this route. When an established infection was treated, uAmB-AG was somewhat more effective than liposomal AmB. In summary, water-soluble polymeric AmB derivatives were found effective and safe for the treatment of leishmanial infections. The conjugates, which are stable and can be produced relatively cheaply (compared to lipid formulations), can be used in the future for the treatment of leishmaniasis infections.

scholarly journals New Insight into Amphotericin B Resistance in Aspergillus terreus

2013 ◽  
Vol 57 (4) ◽  
pp. 1583-1588 ◽  
Author(s):  
Gerhard Blum ◽  
Caroline Hörtnagl ◽  
Emina Jukic ◽  
Thomas Erbeznik ◽  
Thomas Pümpel ◽  
...  
Keyword(s):  
Amphotericin B ◽  
Molecular Basis ◽  
Aspergillus Terreus ◽  
Minor Role ◽  
Content Type ◽  
Ergosterol Content ◽  
Disseminated Aspergillosis ◽  
A Minor

ABSTRACTAmphotericin B (AMB) is the predominant antifungal drug, but the mechanism of resistance is not well understood. We compared thein vivovirulence of an AMB-resistantAspergillus terreus(ATR) isolate with that of an AMB-susceptibleA. terreusisolate (ATS) using a murine model for disseminated aspergillosis. Furthermore, we analyzed the molecular basis of intrinsic AMB resistancein vitroby comparing the ergosterol content, cell-associated AMB levels, AMB-induced intracellular efflux, and prooxidant effects between ATR and ATS. Infection of immunosuppressed mice with ATS or ATR showed that the ATS strain was more lethal than the ATR strain. However, AMB treatment improved the outcome in ATS-infected mice while having no positive effect on the animals infected with ATR. Thein vitrodata demonstrated that ergosterol content is not the molecular basis for AMB resistance. ATR absorbed less AMB, discharged more intracellular compounds, and had better protection against oxidative damage than the susceptible strain. Our experiments showed that ergosterol content plays a minor role in intrinsic AMB resistance and is not directly associated with intracellular cell-associated AMB content. AMB might exert its antifungal activity by oxidative injury rather than by an increase in membrane permeation.

scholarly journals Investigation of the Efficacy of Micafungin in the Treatment of Histoplasmosis Using Two North American Strains of Histoplasma capsulatum

2011 ◽  
Vol 55 (9) ◽  
pp. 4447-4450 ◽  
Author(s):  
Chadi A. Hage ◽  
Patricia Connolly ◽  
Daniel Horan ◽  
Michelle Durkin ◽  
Melinda Smedema ◽  
...  
Keyword(s):  
Amphotericin B ◽  
North American ◽  
Liposomal Amphotericin ◽  
Histoplasma Capsulatum ◽  
Liposomal Amphotericin B ◽  
Content Type ◽  
Yeast Form

ABSTRACTMicafungin alone and combined with liposomal amphotericin B was evaluated against two strains ofHistoplasma capsulatum. Micafungin was activein vitroagainst the mold but not the yeast form but was ineffectivein vivo. Micafungin appears to be ineffective in treatment of histoplasmosis.

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