APOA1 and Alzheimer disease: Considering previously published data about the ability of HDL and apoA-I to bind Aβ in vitro (Koldamova et al., 2001; Paula-Lima et al., 2009; Shih et al., 2014) and reduce Aβ levels in the brain of AD animal models (Robert et al., 2016), we hypothesized that plasma-derived HDL acts by accelerating the Aβ egress from the brain to the blood via “sink effect,” as already speculated for different Aβ binding molecules or particles (Golabek et al., 1995; Mancini et al., 2016).