Caspofungin Cerebral Penetration and Therapeutic Efficacy in Experimental Cerebral Aspergillosis

ABSTRACT Despite best available therapy, cerebral aspergillosis is an often-lethal complication of disseminated aspergillosis. There is an urgent need to expand the currently limited therapeutic options. In this study, we assessed cerebral drug exposure and efficacy of caspofungin (CAS) using a leth...

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Main Authors: Irina Ullmann, Andrea Aregger, Stephen L. Leib, Stefan Zimmerli
Format: Article
Language:English
Published: American Society for Microbiology 2022-06-01
Series:Microbiology Spectrum
Subjects:
Online Access:https://journals.asm.org/doi/10.1128/spectrum.02753-21
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author Irina Ullmann
Andrea Aregger
Stephen L. Leib
Stefan Zimmerli
author_facet Irina Ullmann
Andrea Aregger
Stephen L. Leib
Stefan Zimmerli
author_sort Irina Ullmann
collection DOAJ
description ABSTRACT Despite best available therapy, cerebral aspergillosis is an often-lethal complication of disseminated aspergillosis. There is an urgent need to expand the currently limited therapeutic options. In this study, we assessed cerebral drug exposure and efficacy of caspofungin (CAS) using a lethal infant rat model of cerebral aspergillosis. Eleven-day-old Wistar rats were infected by intracisternal injection of Aspergillus fumigatus conidia. Treatment started after 22 h and was continued for 10 days. Regimens were CAS 1 mg/kg/day intraperitoneally (i.p.), liposomal amphotericin B (L-AmB) 5 mg/kg/day i.p., and both drugs combined at the same dose i.p. Infected controls were given NaCl 0.85% i.p. Primary endpoints assessed were survival, cerebral fungal burden, galactomannan index, and drug concentrations in brain homogenate at 2, 3, 5, and 11 days after infection. Compared to those of controls (4.4 ± 2.7 days), survival times were increased by treatment with CAS alone (10.3 ± 1.7 days; P < 0.0001) and CAS combined with L-AmB (9.3 ± 2.8 days; P < 0.0001). In contrast, survival time of L-AmB-treated animals (4.3 ± 3.1 days) was not different from that of controls. Cerebral fungal burden and galactomannan index declined in all animals over time, without significant differences between controls and treated animals. CAS trough levels in brain tissue were between 0.84 and 1.4 μg/g, concentrations we show to be associated with efficacy. AmB trough levels in brain tissue were higher than the MIC of the A. fumigatus isolate. In summary, CAS concentrations in brain tissue suggest it may be therapeutically relevant and it significantly improved survival in this lethal model of cerebral aspergillosis in nonneutropenic rats. The clinical efficacy of CAS treatment for cerebral aspergillosis merits further study. IMPORTANCE Treatment options for cerebral aspergillosis, an often-lethal disease, are limited. The echinocandins (caspofungin is one of them) are not recommended treatment because their brain tissue penetration is often considered insufficient. In a nursing rat model of cerebral aspergillosis that mimics human disease, we found potentially therapeutically relevant concentrations of caspofungin in brain tissue and prolonged survival of caspofungin-treated animals. The efficacy of caspofungin in the treatment of cerebral aspergillosis documented here, if confirmed in other animal models (especially immunosuppressed murine models) and by using additional Aspergillus isolates across a range of CAS minimal effective concentrations (MECs), would suggest that caspofungin merits further study as a treatment option for patients suffering from aspergillosis disseminated to the brain.
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spelling doaj.art-62c00cd64da946229e7e65870d85c2222022-12-22T03:32:45ZengAmerican Society for MicrobiologyMicrobiology Spectrum2165-04972022-06-0110310.1128/spectrum.02753-21Caspofungin Cerebral Penetration and Therapeutic Efficacy in Experimental Cerebral AspergillosisIrina Ullmann0Andrea Aregger1Stephen L. Leib2Stefan Zimmerli3Institute for Infectious Diseases, University of Bern, Bern, SwitzerlandInstitute for Infectious Diseases, University of Bern, Bern, SwitzerlandInstitute for Infectious Diseases, University of Bern, Bern, SwitzerlandInstitute for Infectious Diseases, University of Bern, Bern, SwitzerlandABSTRACT Despite best available therapy, cerebral aspergillosis is an often-lethal complication of disseminated aspergillosis. There is an urgent need to expand the currently limited therapeutic options. In this study, we assessed cerebral drug exposure and efficacy of caspofungin (CAS) using a lethal infant rat model of cerebral aspergillosis. Eleven-day-old Wistar rats were infected by intracisternal injection of Aspergillus fumigatus conidia. Treatment started after 22 h and was continued for 10 days. Regimens were CAS 1 mg/kg/day intraperitoneally (i.p.), liposomal amphotericin B (L-AmB) 5 mg/kg/day i.p., and both drugs combined at the same dose i.p. Infected controls were given NaCl 0.85% i.p. Primary endpoints assessed were survival, cerebral fungal burden, galactomannan index, and drug concentrations in brain homogenate at 2, 3, 5, and 11 days after infection. Compared to those of controls (4.4 ± 2.7 days), survival times were increased by treatment with CAS alone (10.3 ± 1.7 days; P < 0.0001) and CAS combined with L-AmB (9.3 ± 2.8 days; P < 0.0001). In contrast, survival time of L-AmB-treated animals (4.3 ± 3.1 days) was not different from that of controls. Cerebral fungal burden and galactomannan index declined in all animals over time, without significant differences between controls and treated animals. CAS trough levels in brain tissue were between 0.84 and 1.4 μg/g, concentrations we show to be associated with efficacy. AmB trough levels in brain tissue were higher than the MIC of the A. fumigatus isolate. In summary, CAS concentrations in brain tissue suggest it may be therapeutically relevant and it significantly improved survival in this lethal model of cerebral aspergillosis in nonneutropenic rats. The clinical efficacy of CAS treatment for cerebral aspergillosis merits further study. IMPORTANCE Treatment options for cerebral aspergillosis, an often-lethal disease, are limited. The echinocandins (caspofungin is one of them) are not recommended treatment because their brain tissue penetration is often considered insufficient. In a nursing rat model of cerebral aspergillosis that mimics human disease, we found potentially therapeutically relevant concentrations of caspofungin in brain tissue and prolonged survival of caspofungin-treated animals. The efficacy of caspofungin in the treatment of cerebral aspergillosis documented here, if confirmed in other animal models (especially immunosuppressed murine models) and by using additional Aspergillus isolates across a range of CAS minimal effective concentrations (MECs), would suggest that caspofungin merits further study as a treatment option for patients suffering from aspergillosis disseminated to the brain.https://journals.asm.org/doi/10.1128/spectrum.02753-21cerebral aspergillosisantifungal therapycaspofunginCNS drug penetrationanimal modelrat
spellingShingle Irina Ullmann
Andrea Aregger
Stephen L. Leib
Stefan Zimmerli
Caspofungin Cerebral Penetration and Therapeutic Efficacy in Experimental Cerebral Aspergillosis
Microbiology Spectrum
cerebral aspergillosis
antifungal therapy
caspofungin
CNS drug penetration
animal model
rat
title Caspofungin Cerebral Penetration and Therapeutic Efficacy in Experimental Cerebral Aspergillosis
title_full Caspofungin Cerebral Penetration and Therapeutic Efficacy in Experimental Cerebral Aspergillosis
title_fullStr Caspofungin Cerebral Penetration and Therapeutic Efficacy in Experimental Cerebral Aspergillosis
title_full_unstemmed Caspofungin Cerebral Penetration and Therapeutic Efficacy in Experimental Cerebral Aspergillosis
title_short Caspofungin Cerebral Penetration and Therapeutic Efficacy in Experimental Cerebral Aspergillosis
title_sort caspofungin cerebral penetration and therapeutic efficacy in experimental cerebral aspergillosis
topic cerebral aspergillosis
antifungal therapy
caspofungin
CNS drug penetration
animal model
rat
url https://journals.asm.org/doi/10.1128/spectrum.02753-21
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