Abstract
For nearly 20 years, the primary focus for researchers studying Alzheimer disease has been centered on amyloid-β, such that the amyloid cascade hypothesis has become the “null hypothesis.” Indeed, amyloid-β is, by the current definition of the disease, an obligate player in pathophysiology, is toxic to neurons in vitro, and, perhaps most compelling, is increased by all of the human genetic influences on the disease. Therefore, targeting amyloid-β is the focus of considerable basic and therapeutic interest. However, an increasingly vocal group of investigators are arriving at an “alternate hypothesis” stating that amyloid-β, while certainly involved in the disease, is not an initiating event but rather is secondary to other pathogenic events. Furthermore and perhaps most contrary to current thinking, the alternate hypothesis proposes that the role of amyloid-β is not as a harbinger of death but rather a protective response to neuronal insult. To determine which hypothesis relates best to Alzheimer disease requires a broader view of disease pathogenesis and is discussed herein.
Footnotes
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This work is supported by National Institutes of Health Grant AG026151 and Philip Morris USA, Inc., and Philip Morris International.
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Article, publication date, and citation information can be found at http://jpet.aspetjournals.org.
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doi:10.1124/jpet.106.114009.
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ABBREVIATIONS: Aβ, amyloid-β; AD, Alzheimer disease; AβPP, amyloid-β protein precursor; FAD, familial Alzheimer disease; Tg, transgenic; PS, presenilin; ROS, reactive oxygen species.
- Received December 8, 2006.
- Accepted January 16, 2007.
- The American Society for Pharmacology and Experimental Therapeutics
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