INS and type 2 diabetes mellitus: These findings indicate an intimate relationship between diabetes and AD which led to the proposal to consider AD as “type 3 diabetes” (37), and prompted clinical trials testing the efficacy of anti-T2DM drugs such as liraglutide (38), thiazolidinediones (39), intranasal insulin (40) and metformin (41) in AD with positive preliminary results (13).