title: Reconstituted high density lipoprotein enriched with the polyene antibiotic amphotericin B.
abstract: The polyene antibiotic amphotericin B (AMB) is an effective antifungal agent whose therapeutic potential is limited by poor aqueous solubility and toxicity toward host tissues. Addition of apolipoprotein A-I to a multilamellar phospholipid vesicle dispersion containing 20% (w/w) AMB induces the formation of reconstituted high density lipoprotein (rHDL), with solubilization of the antibiotic. Density gradient ultracentrifugation resulted in flotation of the complexes to a density of 1.16 g/ml, and negative stain electron microscopy revealed a population of disk-shaped particles. Native gradient polyacrylamide gel electrophoresis indicated a particle diameter of approximately 8.5 nm. Absorbance spectroscopy provided evidence for AMB integration into the lipid milieu. AMB-rHDLs were potent inhibitors of Saccharomyces cerevisiae growth, yielding 90% growth inhibition at <1 microg/ml yeast culture. In studies with pathogenic fungal species, similar growth inhibition characteristics were observed. Compared with AMB-deoxycholate micelles, AMB-rHDL displayed greatly attenuated red blood cell hemolytic activity and decreased toxicity toward cultured hepatoma cells. In in vivo studies in immunocompetent mice, AMB-rHDLs were nontoxic at 10 mg/kg, and they showed efficacy in a mouse model of candidiasis at concentrations as low as 0.25 mg/kg. These results indicate that AMB-rHDLs constitute a novel formulation that effectively solubilizes the antibiotic and elicits strong in vitro and in vivo antifungal activity with no observed toxicity at therapeutic doses.
authors.affiliation: Lipid Biology in Health and Disease Research Group, Children's Hospital Oakland Research Institute, Oakland, CA 94609, USA.
authors.forename: Michael N
authors.initials: MN
authors.lastname: Oda
authors.forename: Peter L
authors.initials: PL
authors.lastname: Hargreaves
authors.forename: Jennifer A
authors.initials: JA
authors.lastname: Beckstead
authors.forename: Katherine A
authors.initials: KA
authors.lastname: Redmond
authors.forename: Rik
authors.initials: R
authors.lastname: van Antwerpen
authors.forename: Robert O
authors.initials: RO
authors.lastname: Ryan
mesh_terms: D000666:Amphotericin B / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D000818:Animals; D000935:Antifungal Agents / Q000494:pharmacology; D016632:Apolipoprotein A-I / Q000737:chemistry; D001232:Aspergillus fumigatus / Q000187:drug effects; D002176:Candida albicans / Q000187:drug effects; D002177:Candidiasis / Q000188:drug therapy* / Q000382:microbiology; D045744:Cell Line, Tumor; D049109:Cell Proliferation / Q000187:drug effects; D002470:Cell Survival / Q000187:drug effects; D002499:Centrifugation, Density Gradient; D003455:Cryptococcus neoformans / Q000187:drug effects; D004337:Drug Carriers; D004912:Erythrocytes / Q000187:drug effects; D005260:Female; D006801:Humans; D008075:Lipoproteins, HDL / Q000737:chemistry / Q000494:pharmacology / Q000627:therapeutic use*; D051379:Mice; D008807:Mice, Inbred BALB C; D008854:Microscopy, Electron; D010743:Phospholipids / Q000737:chemistry; D012441:Saccharomyces cerevisiae / Q000187:drug effects; D013053:Spectrophotometry; D013056:Spectrophotometry, Ultraviolet; D016019:Survival Analysis
chemical_list: D000935:Antifungal Agents; D016632:Apolipoprotein A-I; D004337:Drug Carriers; D008075:Lipoproteins, HDL; D010743:Phospholipids; C068538:liposomal amphotericin B; D000666:Amphotericin B