INS and type 2 diabetes mellitus: These include i) all people who underwent complete pancreatectomy, ii) all subjects suffering from type 1 diabetes (T1D; a condition in which insulin-producing pancreatic β-cells are destroyed)22, and iii) a significant percentage of subjects affected by type 2 diabetes (T2D; a disease in which pancreatic β-cells can undergo exhaustion, failure, and/or dedifferentiation)20,21.