APOE and amyloidosis: Studies in human and transgenic mice have shown that the Aβ levels in the brain and the amyloid plaque load are ApoE isoform-dependent (ε4>ε3>ε2) (Reiman et al., 2009), suggesting that ApoE plays an important role in the regulation of Aβ metabolism, aggregation, and deposition (Bales et al., 2009).