INS and type 1 diabetes mellitus: Moreover, it is important to underscore that T1D is characterized by significant interindividual heterogeneity regarding pathophysiological, genetic, immunopathological and metabolic features (e.g., severity of autoimmune responses against pancreatic beta cells, rate of beta-cell loss, proportion of residual insulin-containing pancreatic islets, and degree of C-peptide preservation) [33,34,35].