PGP and early-onset autosomal dominant Alzheimer disease: Neutralizing the Wnt-pathway inhibitor DKK1 in APPswe/PS1 mice restored β-catenin protein levels, attenuated Aβ pathologies, and increased BBB integrity and P-gp expression [71], further supporting the role of the Wnt/β-catenin signaling in the regulation of P-gp levels in the BBB during Alzheimer‘s disease [72].