MT-ND4 and type 2 diabetes mellitus: Representative pancreas images shown in Fig. 2 are from roughly selected specimens grouped by available clinical information: (1) relatively young and healthy subjects (Fig. 2A: ND1, ND3, ND4); (2) non-diabetic elderly subjects (Fig. 2B: ND11, ND13, ND15); and (3) subjects with T2D (Fig. 2C: D2, D9, D11).