INS and type 2 diabetes mellitus: Both mechanisms have been implicated in IIS—one of the key Aβ proteases, insulin degrading enzyme (IDE) or insulysin (38), is involved in both insulin and Aβ degradation and transthyretin, recently implicated in Aβ proteolysis as well as Aβ clearance [19], is elevated in both insulin resistant mice and people with type II diabetes [20,21].