INS and type 2 diabetes mellitus: DM is classified into type 1 DM (T1DM), resulting from autoimmune-induced β-cell death; type 2 DM (T2DM), due to insulin resistance or impaired insulin secretion (that accounts for >90% of diagnosed DM cases); gestational DM; and specific types of DM due to other causes, e.g., chemical-induced diabetes [97].