PGP and Alzheimer disease: There are several ways in which decreased P-gp function could contribute to AD pathogenesis, but it is likely that it would contribute to accumulation of Aβ in the brain, as studies have shown that P-gp can directly interact with Aβ and that blocking P-gp function decreases transport of Aβ (Kuhnke et al., 2007; Lam et al., 2001; Van Assema et al., 2012).