INS and diabetes mellitus: Diabetes mellitus is a chronic disease characterised by elevated blood glucose levels (hyperglycaemia), originated by an autoimmune β-cell destruction (type 1 diabetes mellitus, T1DM) or a progressive loss of pancreatic function due to inadequate insulin secretion by the β cells as a consequence of insulin resistance exerted by peripheral tissues such as liver, muscle, and adipose tissue (type 2 diabetes mellitus, T2DM) [56].