Conclusions: ED (as assessed by brachial FMD and serum 5-HT) is more severe in in diabetic patients with severe CAD scheduled for CABG surgery, while oxidative stress (as evaluated through serum SOD-1 and LOX-1 concentrations) was not influenced by the presence of T2DM in this specific population. This evidence concerns the gene SOD1 and type 2 diabetes mellitus.