Our prior work indicates that insulin degrading enzyme (IDE) contributes to the pathology in a mixed model of type 2 diabetes and AD [9], and that adenosine 3,5′-cyclic monophosphate/protein kinase A (cAMP/PKA) signaling pathway contributes to neuronal apoptosis via regulating IDE expression in a mixed model of type 2 diabetes and AD [10]. Here, IDE is linked to type 2 diabetes mellitus.