Annular protofibrils (APFs) represent a new and distinct class of amyloid structures formed
by disease-associated proteins. In vitro, these pore-like structures have been implicated in
membrane permeabilization and ion homeostasis via pore formation. Still, evidence for their
formation and relevance in vivo is lacking. Herein, we report that APFs are in a distinct
pathway from fibril formation in vitro and in vivo. In human Alzheimer disease brain samples,
amyloid-β APFs were associated with diffuse plaques, but not compact plaques; moreover …