sNEP-expressing NSCs decrease Aβ plaque load within the subiculum and its efferent targets. (A) Three months post transplantation, Aβ plaque load (red, 6E10) is reduced by as much as 60% within several regions ipsilateral to the sNEP-expressing NSC grafts. As quantified in (B), Aβ plaques are significantly reduced within the subiculum (P = 0.007) directly adjacent to the transplant site, whereas reductions within CA1 fail to reach significance (P = 0.18). Interestingly, Aβ load is also significantly reduced within the amygdala (P = 0.039) and medial septum (P = 0.05), two regions that receive inputs directly from the subiculum. Aβ measurements were quantified from opposing sides of the brain from the same individual animals (n = 5); the data were, therefore, compared by paired t-test. Error bars represent standard error of the mean (SEM). Scale Bar = 140 μm. Aβ, beta- amyloid; NSCs, neural stem cells; sNEP, secreted neprilysin.