methylamphotericin-b and Brain-Diseases

The intracisternal administration of amphotericin B (AmB) and its mono-methyl ester derivative (AME), via direct intraventricular injection (0.01 to 5 mg/ml, 6 microliters) in adult female Wistar rats, revealed that AmB was significantly more toxic than AME, as measured by weight loss, lethargy, death, and central nervous system histopathology. Light and electron microscopy confirmed a greater neurotoxicity for AmB, manifested as edema and modest gliosis extending along and beyond the injection tract. Neuronal degeneration and myelin damage were present in AmB-treated (1 mg/ml) animals but were present only modestly in animals treated with AME at a fivefold greater concentration. Intravenous administration of AmB to adult female Wistar rats as five daily doses of 5 mg/kg of body weight resulted in significant weight loss and some deaths. Histopathologic examination of the brains, spinal cords, and sural nerves of surviving animals revealed neurotoxicity manifested by neuronal degeneration, gliosis, and myelin edema. In sharp contrast, similar treatment with AME at a 10-fold greater dose resulted in neither death nor significant neurotoxicity. The administration of five daily doses of a mixture of AME-AmB (9:1; wt/wt) at 50 mg/kg of body weight resulted in neurotoxicity. These results indicate that AmB exhibits significantly greater in vivo neurotoxicity than AME.

Topics: Amphotericin B; Animals; Antifungal Agents; Body Weight; Brain Diseases; Drug Combinations; Female; Injections, Intravenous; Injections, Intraventricular; Nerve Degeneration; Neurons; Peripheral Nervous System Diseases; Rats; Rats, Wistar

Clinical and autopsy studies of 14 patients treated with amphotericin B methyl ester (AME) for focal, disseminated, and nervous system mycotic infections revealed a high incidence of progressive neurologic dysfunction (dementia, akinesia, mutism, hyperreflexia, and tremor) and diffuse white matter degeneration. All of seven patients who received greater than 9.8 g of AME intravenously developed severe neurologic and neuropathologic changes. Two of three patients given 5-7.2 g of AME developed less severe neurologic symptoms; all three had mild diffuse white matter gliosis. Four patients given less than 1.5 g of AME had no bran abnormalities except those related to coccidioidal meningitis. Thirty-one control patients who died on untreated or amphotericin B-treated coccidioidal meningitis showed no diffuse white matter abnormalities. These findings indicate that prolonged administration of AME and/or other contaminating polyenes injures human white matter. Long-term animal studies, with particular attention to nervous system histology, must precede human use of other polyene derivatives.

Topics: Adolescent; Adult; Aged; Amphotericin B; Aspergillosis; Astrocytes; Brain; Brain Diseases; Child; Coccidioidomycosis; Demyelinating Diseases; Gliosis; Humans; Lung Diseases, Fungal; Middle Aged; Myelin Sheath

Topics: Amphotericin B; Animals; Brain Diseases; Coccidioidomycosis; Dogs; Humans; Macaca mulatta; Mycoses; Nervous System Diseases