APOE and Alzheimer disease: Our results support new perspectives on apoE’s role in AD pathogenesis, including: 1) that circulating apoE may play a greater role in Aβ clearance than previously appreciated, and 2) that interventions based on apoE-enriched HDL may be effective in promoting Aβ clearance across the vascular wall, raising the possibility of a systemic preventative, companion or therapeutic approach for AD.