This appears similar to the decline in beta-cell function over time seen in human T2D and involves reduced expression of key beta-cell transcription factors such as Pdx1 and Neuronal differentiation gene 1 (NeuroD1), and genes protective of cellular oxidative stress such as superoxide dismutase 1 (Sod1) (101, 153). This evidence concerns the gene SOD1 and type 2 diabetes mellitus.