Figure 4.

Differences in Aβ₄₀/Aβ₄₂ ratios between ISF, CSF, and brain tissue with age. In both the ISF and CSF fluids, the Aβ₄₀/Aβ₄₂ ratio increases significantly with age (p = 0.0466, n = 10; and p = 0.0413, n = 9, respectively), primarily attributable to an increase in Aβ₄₀ within ISF and a decrease in Aβ₄₂ in CSF. In contrast, carbonate (Carb) and guanidine (Guan) of hippocampal tissue reveals a significant decrease in the Aβ₄₀/Aβ₄₂ ratio with age (p < 0.0001 and p < 0.001, respectively; n = 10). This change coincides with a tremendous deposition of Aβ₄₂ in older mice. Inset, Enlargement of hippocampal tissue lysate data.