Neurobiology of aging
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Neurobiology of aging · May 2005
Comparative StudyAge- and region-dependent alterations in Abeta-degrading enzymes: implications for Abeta-induced disorders.
Accumulation of amyloid beta-protein (Abeta) is a fundamental feature of certain human brain disorders such as Alzheimer's disease (AD) and Down syndrome and also of the skeletal muscle disorder inclusion body myositis (IBM). Emerging evidence suggests that the steady-state levels of Abeta are determined by the balance between production and degradation. Although the proteolytic processes leading to Abeta formation have been extensively studied, less is known about the proteases that degrade Abeta, which include insulin-degrading enzyme (IDE) and neprilysin (NEP). ⋯ We further show that IDE is more oxidized in the hippocampus compared to the cerebellum of AD patients. In muscle, we find differential levels of IDE and NEP in fast versus slow twitch muscle fibers that varies with aging. These findings suggest that age- and region-specific changes in the proteolytic clearance of Abeta represent a critical pathogenic mechanism that may account for the susceptibility of particular brain or muscle regions in AD and IBM.