Amyloid

Oxidative stress increases levels of amyloid-beta

Oxidative damage is associated with Alzheimer's Disease (AD) and mild cognitive impairment (MCI) but its relationship to the development of neuropathological lesions involving accumulation of amyloid-beta (Abeta) peptides and hyperphosphorylated tau protein remains poorly understood. Scientists show that inducing oxidative stress in primary chick brain neurons by exposure to sub-lethal doses of H(2)O(2 )increases levels of total secreted endogenous Abeta by 2.4-fold after 20 hours. This occurs in the absence of changes to intracellular amyloid precursor protein (APP) or tau protein levels, while heat shock protein 90 (Hsp90) is elevated 2.5-fold. These results are consistent with the hypothesis that aging- associated oxidative stress contributes to increasing Abeta generation and up-regulation of molecular chaperones in AD. ...Aging Cell. 2008 Aug 1