The supersaturation perspective on the amyloid hypothesis

Development of therapeutic interventions for Alzheimer's over the past three decades has been guided by the amyloid hypothesis, which puts A beta deposition as the initiating event of a pathogenic cascade leading to dementia. In the current form, the amyloid hypothesis lacks a comprehensive framework that considers the complex nature of A beta aggregation. The explanation of how A beta deposition leads to downstream pathology, and how reducing A beta plaque load via anti-amyloid therapy can lead to improvement in cognition remains insufficient. In this perspective we integrate the concept of A beta supersaturation into the amyloid hypothesis, laying out a framework for the mechanistic understanding and therapeutic intervention of Alzheimer's disease. We discuss the important distinction between in vitro and in vivo patterns of A beta aggregation, the impact of different aggregation stages on therapeutic strategies, and how future investigations could integrate this concept in order to produce a more thorough understanding and better treatment for Alzheimer's and other amyloid-related disorders. The current amyloid hypothesis does not capture the full complexity of A beta aggregation. Here we lay out a supersaturation framework to better understand the molecular mechanism of Alzheimer's disease and to develop more effective treatment strategies.