SOD3 and type 1 diabetes mellitus: Extracellular SOD3 expression has also been shown to be reduced with the increased production of the superoxide radical (O2-•) associated with the decreased expression of the Cu transporter protein ATP7A, in blood vessels from mice with T1DM and T2DM [54], as well as in patients and those from high-fat-diet-induced T2DM [55].