APP and cerebral amyloid angiopathy: Besides cerebral amyloid angiopathy (CAA), the BBB of AD subjects is characterized by a loss of P-gp (efflux) and neprilysin (degradation enzyme), as well as an increase in amyloid precursor protein (APP) and β-secretase (key enzyme of the amyloidogenic pathway), all in close association with ante mortem cognitive decline [202].