amphotericin-b--deoxycholate-drug-combination and Disease-Models--Animal

Cryptococcosis is a life-threatening fungal infection, and its current treatment is toxic and subject to resistance. Drug repurposing represents an interesting approach to find drugs to reduce the toxicity of antifungals. In this study, we evaluated the combination of N-acetylcysteine (NAC) with amphotericin B (AMB) for the treatment of cryptococcosis. We examined the effects of NAC on fungal morphophysiology and on the macrophage fungicidal activity 3 and 24 hours post inoculation. The therapeutic effects of NAC combination with AMB were investigated in a murine model with daily treatments regimens. NAC alone reduced the oxidative burst generated by AMB in yeast cells, but did not inhibit fungal growth. The combination NAC + AMB decreased capsule size, zeta potential, superoxide dismutase activity and lipid peroxidation. In macrophage assays, NAC + AMB did not influence the phagocytosis, but induced fungal killing with different levels of oxidative bursts when compared to AMB alone: there was an increased reactive oxygen species (ROS) after 3 hours and reduced levels after 24 hours. By contrast, ROS remained elevated when AMB was tested alone, demonstrating that NAC reduced AMB oxidative effects without influencing its antifungal activity. Uninfected mice treated with NAC + AMB had lower concentrations of serum creatinine and glutamate-pyruvate transaminase in comparison to AMB. The combination of NAC + AMB was far better than AMB alone in increasing survival and reducing morbidity in murine-induced cryptococcosis, leading to reduced fungal burden in lungs and brain and also lower concentrations of pro-inflammatory cytokines in the lungs. In conclusion, NAC + AMB may represent an alternative adjuvant for the treatment of cryptococcosis.

Topics: Acetylcysteine; Amphotericin B; Animals; Antifungal Agents; Brain; Creatinine; Cryptococcosis; Cryptococcus; Deoxycholic Acid; Disease Models, Animal; Drug Combinations; Drug Repositioning; Female; Kidney; Lung; Macrophages; Mice; Mice, Inbred C57BL; Microbial Sensitivity Tests; Reactive Oxygen Species

In severe cases of sporotrichosis, it is recommended to use amphotericin B deoxycholate (D-AMB) or its lipid formulations and/or in association with itraconazole (ITC). Our aim was to evaluate the antifungal efficacy of a poly-aggregated amphotericin B (P-AMB), a nonlipid formulation, compared with D-AMB on systemic sporotrichosis caused by Sporothrix brasiliensis. In vitro assays showed that Sporothrix schenckii sensu stricto and S. brasiliensis yeast clinical isolates were susceptible to low concentrations of P-AMB and D-AMB. Although P-AMB presented a higher minimal inhibitory concentration (MIC) compared to D-AMB, its cytotoxic effect on renal cells and erythrocytes was lower. For the in vivo assays, male BALB/c mice were intravenously infected with S. brasiliensis yeasts, and P-AMB or D-AMB was administered 3 days post-infection. The efficacy of five therapeutic regimens was tested: intravenous monotherapy with P-AMB or D-AMB, intravenous pulsed-therapy with P-AMB or D-AMB, and intravenous therapy with P-AMB, followed by oral ITC. These treatments increased murine survival and controlled the fungal burden in the liver, spleen, lungs, and kidneys. However, only D-AMB monotherapy or the pulsed-therapies with D-AMB or P-AMB led to 100% survival of the mice 45 days post-infection; only pulsed administration of D-AMB was able to control the fungal load in all organs 45 days post-infection. Accordingly, the histopathological findings showed reductions in the fungal burden and inflammatory reactions in these treatment regimens. Together, our results suggest that the P-AMB formulation could be considered as an alternative drug to D-AMB for treating disseminated sporotrichosis.

Topics: Amphotericin B; Animals; Antifungal Agents; Cell Survival; Colony Count, Microbial; Deoxycholic Acid; Disease Models, Animal; Drug Combinations; Male; Mice; Mice, Inbred BALB C; Microbial Sensitivity Tests; Sporothrix; Sporotrichosis; Survival Rate

The aim of this work is to design new chitosan conjugates able to self-organize in aqueous solution in the form of micrometer-size platelets. When mixed with amphotericin B deoxycholate (AmB-DOC), micro-platelets act as a drug booster allowing further improvement in AmB-DOC anti-Candida albicans activity.. Micro-platelets were obtained by mixing oleoyl chitosan and α-cyclodextrin in water. The formulation is specifically-engineered for mucosal application by dispersing chitosan micro-platelets into thermosensitive pluronic. These results demonstrate for the first time the ability of flattened chitosan micro-platelets to have synergistic activity with AmB-DOC against C. albicans candidiasis and highlight the importance of rheological and mucoadhesive behaviors of hydrogels in the efficacy of the treatment.

Topics: alpha-Cyclodextrins; Amphotericin B; Animals; Antifungal Agents; Blood Platelets; Candida albicans; Candidiasis; Chemistry, Pharmaceutical; Chitosan; Deoxycholic Acid; Disease Models, Animal; Drug Combinations; Female; Hydrogels; Mice; Mice, Inbred BALB C; Mucous Membrane; Nanoparticles; Poloxamer; Swine

Cryptococcal meningoencephalitis is an urgent global health problem. Induction regimens using 14 days of amphotericin B deoxycholate (dAmB) are considered the standard of care but may not be suitable for resource-poor settings. We investigated the efficacy of conventional and abbreviated regimens of dAmB for cryptococcal meningoencephalitis in both murine and rabbit models of cryptococcal meningoencephalitis. We examined the extent to which immunological effectors contribute to the antifungal effect. We bridged the results to humans as a first critical step to define regimens suitable for further study in clinical trials. There were significant differences in the murine plasma-versus-cerebrum dAmB concentration-time profiles. dAmB was detectable in the cerebrum throughout the experimental period, even following the administration of only three doses of 3 mg/kg. dAmB induced a fungistatic effect in the cerebrum with a 2- to 3-log10 CFU/g reduction compared with controls. The effect of 3 days of therapy was the same as that of daily therapy for 14 days. There was no evidence of increased numbers of CD3(+) CD4(+) or CD3(+) CD8(+) cells in treated mice to account for the persistent antifungal effect of an abbreviated regimen. The administration of dAmB at 1 mg/kg/day for 3 days was the same as daily therapy in rabbits. The bridging studies suggested that a human regimen of 0.7 mg/kg/day for 3 days resulted in nearly maximal antifungal activity in both the cerebrum and cerebrospinal fluid. An abbreviated regimen (3 days of therapy) of dAmB appears to be just as effective as conventional induction therapy for cryptococcal meningoencephalitis.. Cryptococcal meningitis is a significant and neglected infection that is associated with excessive morbidity and mortality. In well-resourced health care settings, induction therapy with at least 2 weeks of amphotericin B deoxycholate (dAmB) is advocated. Multiple clinical studies suggest that dAmB is the drug of choice for cryptococcal meningitis. In many parts of the world where the burden of cryptococcal meningitis is highest, it is infeasible to administer dAmB for prolonged periods. This paper provides the experimental basis for the efficacy of abbreviated regimens of dAmB for cryptococcal meningitis. The concept was explored in two well-validated laboratory animal models of cryptococcal meningitis, and the results were bridged to humans by using a range of mathematical modeling techniques. A 3-day regimen is as effective as the standard 14-day course. An abbreviated regimen is significantly more feasible and may enable better antifungal therapy to be administered to many patients with this frequently lethal disease.

Topics: Amphotericin B; Animals; Antifungal Agents; Cerebrospinal Fluid; Cerebrum; Deoxycholic Acid; Disease Models, Animal; Drug Combinations; Male; Meningitis, Cryptococcal; Mice; Plasma; Rabbits

Immune cells express the vitamin D receptor and vitamin D metabolizing enzymes. Favorable vitamin D effects have been indicated in tuberculosis. Vitamin D deficiency increases T helper (Th) 2 responses to Aspergillus, and it suppresses Th2 responses in cystic fibrosis-allergic bronchopulmonary aspergillosis. Can vitamin D modulate the proinflammatory effects of amphotericin B (AmB) therapy in aspergillosis? Groups of mice were infected intravenously (IV) with 3-8 × 10(6) Aspergillus fumigatus conidia. In six experiments, doses of 0.08, 2, or 4 μg/kg calcitriol (active form of vitamin D) were given intraperitoneally +/- AmB-deoxycholate (AmBd) at 0.4, 0.8, 1.2, 1.8, 3.3, or 4.5 mg/kg or 0.8 or 1.2 mg/kg IV. Calcitriol doses were selected to range from doses used in humans to those just below doses shown to decalcify murine bones. In most experiments, doses of calcitriol and AmBd (or control diluents) were given five times, on alternate days, to minimize drug-drug interactions. Calcitriol treatment began on the day of challenge, and survival assessed for 10 days. In no experiments did calcitriol alone significantly worsen or enhance survival or affect residual infection in survivors. Calcitriol also did not affect the efficacy of AmBd. In a representative experiment, AmBd at 0.8 or 1.2 mg/kg IV alone +/- calcitriol at 2 μg/kg enhanced survival (P ≤ 0.01). However, the AmBd regimens with calcitriol were not different than those without, and calcitriol alone was identical to controls. In disseminated invasive aspergillosis, calcitriol did not affect outcome nor influence antifungal efficacy.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Calcitriol; Colony Count, Microbial; Deoxycholic Acid; Disease Models, Animal; Drug Combinations; Female; Mice; Survival Analysis

Invasive pulmonary aspergillosis remains problematic in immunocompromised patient populations. We studied potential therapeutic options in a murine model of pulmonary aspergillosis in triamcinolone-suppressed DBA/2 mice infected intranasally with conidia from Aspergillus fumigatus. Mice were treated with liposomal-amphotericin B (AmBi; AmBisome), lipid-complexed amphotericin B (ABLC; Abelcet), voriconazole (VCZ), micafungin (MICA), caspofungin (CAS) or deoxycholate amphotericin B (AMBd) given alone or in combination. Monotherapy with AmBi, ABLC, AMBd, CAS or MICA had activity in prolonging survival; however, only AMBd or CAS reduced fungal burden in the lungs and kidneys. Combinations of AmBi plus CAS or MICA prolonged survival, but were not better than monotherapy. VCZ was ineffective and AMBd plus CAS showed a possible antagonism. AmBi or ABLC at higher dosages, or loading-doses of AmBi resulted in reduced survival. Histopathology showed increased incidence of serious renal and mild hepatic toxicity in triamcinolone-treated mice given an amphotericin B regimen compared to no or only triamcinolone (minimal renal changes occurred with CAS or VCZ with or without triamcinolone); suggestive of combined toxicity of triamcinolone and the amphotericin B in AmBi or ABLC. Infected treated mice showed progressive pulmonary disease including abscesses, angioinvasion and abundant intralesional fungi. High loading-doses of AmBi were associated with nephrosis and damage to other tissues. No monotherapy or combination regimen showed superiority for the treatment of pulmonary aspergillosis in corticosteroid suppressed mice and the potential for combined drug toxicity was enhanced in these mice. High dosages of lipid-formulated amphotericin B also proved unsatisfactory. Additional studies are needed to evaluate improved treatment.

Topics: Amphotericin B; Animals; Antifungal Agents; Aspergillus fumigatus; Caspofungin; Colony Count, Microbial; Deoxycholic Acid; Disease Models, Animal; Drug Combinations; Drug Therapy, Combination; Echinocandins; Humans; Invasive Pulmonary Aspergillosis; Lipopeptides; Male; Micafungin; Mice; Mice, Inbred DBA; Pyrimidines; Triazoles; Voriconazole

The objective of this study was to investigate the efficacy of liposomal amphotericin B (L-AMB) at a clinical dose (3 mg/kg) against six species (5 genera) of Zygomycetes in a murine lethal infection model, and to compare findings with those for deoxycholate amphotericin B (D-AMB). The correlation between in-vitro activity and in-vivo efficacy of L-AMB was also investigated. Cyclophosphamide-treated mice were inoculated intravenously with conidial suspensions. Four hours or 1 day after inoculation, a single dose of L-AMB or D-AMB was administered intravenously. The number of mice that survived for 14 days was recorded. L-AMB at a dose of at least ≥1 mg/kg significantly prolonged the survival time of infected mice compared with the control group. The ED₅₀ of L-AMB was nearly equivalent to that of D-AMB, except for the treatment initiated on day 1 in the Rhizopus oryzae model. At the maximum tolerated dose (MTD) of each agent, survival percentages with L-AMB (10 mg/kg) were equal to or higher than those with D-AMB (1 mg/kg). The ED₅₀ of L-AMB decreased as the MIC against the infecting strain decreased. In conclusion, L-AMB was effective at a clinical dosage, and at the MTD the efficacy of L-AMB was equal or superior to that of D-AMB in a murine model of disseminated zygomycosis. The in-vivo activity of L-AMB was correlated with its in-vitro activity.

Topics: Amphotericin B; Animals; Antifungal Agents; Deoxycholic Acid; Disease Models, Animal; Drug Combinations; Humans; Male; Mice; Microbial Sensitivity Tests; Mucorales; Mucormycosis; Species Specificity; Survival Rate; Treatment Outcome

Amphotericin B (AmB) was formulated in trilaurin-based emulsomes (nanosize lipid particles) stabilized by soya phosphatidylcholine (PC), as a new delivery system for macrophage targeting for the treatment of visceral leishmaniasis (VL). Emulsomes were modified by coating them with macrophage-specific ligand (O-palmitoyl mannan, OPM). The antileishmanial activity of AmB-deoxycholate (AmB-Doc) and emulsome entrapped AmB was tested in vitro in Leishmania donovani infected macrophage-amastigote system (J774A.1 cells), which showed higher efficacy of OPM grafted AmB emulsomes (TLEs-OPM) over plain AmB emulsomes (TLEs) and AmB-Doc. The in vivo antileishmanial activity of the AmB (0.5 mg/kg) was tested in AmB-Doc, TLEs and TLEs-OPM forms against VL in L. donovani infected hamsters. Formulation TLEs-OPM eliminated intracellular amastigotes of L. donovani within splenic macrophages more efficiently (73.7 +/- 6.7% parasite inhibition) than the formulation TLEs (51.7 +/- 5.4% parasite inhibition) (P < 0.01) or AmB-Doc (30.4 +/- 4.8% parasite inhibition) (P < 0.001). Our results suggest that these newer formulations (plain and ligand appended emulsomes) are a promising alternative to the conventional AmB-Doc formulation for the treatment of VL.

Topics: Amphotericin B; Animals; Cricetinae; Deoxycholic Acid; Disease Models, Animal; Drug Carriers; Drug Combinations; Leishmania donovani; Leishmaniasis, Visceral; Macrophages; Male; Mesocricetus; Mice; Nanoparticles; Trypanocidal Agents

The efficacy of AmBisome, a liposomal formulation of amphotericin B, was compared with that of Fungizone (amphotericin B desoxycholate), in a rat model of unilateral, pulmonary aspergillosis. Repeated administration of cyclophosphamide resulted in persistent, severe granulocytopenia. The left lung was inoculated with a conidial suspension of Aspergillus fumigatus, thus establishing an unilateral infection. Antifungal treatment was started 40 h after fungal inoculation, at which time mycelial disease was confirmed by histological examination. Both Fungizone 1 mg/kg and AmBisome 10 mg/kg resulted in increased survival in terms of delayed as well as reduced mortality. Quantitative cultures of lung tissue showed that only AmBisome 10 mg/kg resulted in reduction of the number of fungal cfus in the inoculated left lung. Compared with Fungizone, both AmBisome 1 mg/kg/day and AmBisome 10 mg/kg/day significantly prevented dissemination from the infected left lung to the right lung. In addition, both AmBisome regimens reduced hepatosplenic dissemination, and the 10 m/kg dosage fully prevented this complication. In conclusion, when compared with Fungizone, in this model AmBisome is more effective in reducing dissemination of unilateral, pulmonary aspergillosis, even when given in relatively low dosage. Such low dosages may have a place in prophylactic settings.

Topics: Agranulocytosis; Amphotericin B; Animals; Antifungal Agents; Aspergillosis; Aspergillus fumigatus; Deoxycholic Acid; Disease Models, Animal; Drug Combinations; Liposomes; Lung Diseases, Fungal; Rats