BACE1 and Alzheimer disease: While the mechanism of BACE1 elevation in brains of AD patients or mouse models of AD is not yet clear, recent data indicate that BACE1 levels are upregulated during stresses associated with AD risk, such as energy deprivation [39, 68], hypoxia and stroke [56, 71, 84], oxidative stress [61], and traumatic brain injury [2, 65].