APP and Alzheimer disease: Importantly, the AD plaque core contains not only Aβ—as thought [61,62,63]—but also other potential products of APP processing [22,64], other proteinaceous and nonproteinaceous components, including glycosaminoglycan, collagen, lipids, metal ions, reactive oxygen species, inflammatory proteins, and nucleic acids [65,66,67,68,69,70,71,72,73,74,75,76,77].