Importantly, apolipoprotein E4 (APOE4), which is a major susceptibility factor for the development of AD has also been linked to BBB dysfunction and injury to pericytes in both AD models and in human carriers (Lane-Donovan and Herz, 2017; Uddin et al., 2019; Montagne et al., 2020). This evidence concerns the gene APOE and Alzheimer disease.