Amyloid β clearance outside the brain and its relation to dementia

Abstract

Amyloid β (Aβ) is produced in the neurons and transported into the vessel walls and perivascular space through the extracellular space. These pathways are designated as intramural periarterial drainage (IPAD) pathway or glymphatic system in the brain. Overproduction of Aβ or alternatively, stagnation of Aβ transportation may lead to accumulation of amyloid fibrils in the vessel, thereby causing cerebral amyloid angiopathy (CAA). Spontaneous antibody production against Aβ occurs in patients with CAA, and induce CAA–related inflammation (CAA–ri). In terms of cellular mechanism and symptomatology, this entity is very close to amyloid–related imaging abnormalities (ARIA) which is often encountered in the patients during the course of amyloid vaccination treatment. This review overviews mechanisms of Aβ clearance in the brain and discuss on the Aβ antibody–related pathological conditions, including CAA–ri and ARIA.