PGP and Alzheimer disease: Additionally, a significant rise in Aβ1-42 content in the hippocampus of SAMP8 mice was observed, and abnormalities were noted in the P-gp/ECS axis, the RAGE/LRP1 receptor system, as well as MRP2 and Mfsd2a levels, suggesting that the dysregulation of BBB transport-related proteins and receptors in AD contributes to excessive Aβ accumulation.