In addition to these effects on Aβ transport and aggregation, post mortem studies using brain tissue of patients with AD revealed significantly increased rate of pericyte and perivascular breakdown in APOE-ε4 samples when compared with -ε3 and non-AD control samples, accompanied by increases in the inflammatory cytokine CypA and the matrix metalloprotease-9 (MMP-9) [72]. This evidence concerns the gene PPIA and Alzheimer disease.