ABCB1 and Alzheimer disease: In human, experiments on post-mortem tissue samples of AD patients showed decreased expression levels of ABCB1 in brain endothelial cells of microvessels that surround Aβ deposits (Vogelgesang et al., 2002), and almost no expression of ABCB1 in brain endothelial cells was detected in post-mortem tissue samples obtained from CAA patients (Vogelgesang et al., 2004).