MPO and diabetes mellitus: The diabetes-induced free radicals that result from enzymatic reactions and activation of the seven most important oxidative enzymes like cyclooxygenases (COX), cytochrome P450 (CYP450), lipoxygenase (LOX), myeloperoxidase (MPO), NADPH oxidase (NOX), uncoupled endothelial nitric oxide synthase (eNOS), and xanthine oxidase (XOX) contribute as much as those from the mitochondria as shown in Figure 3 [87, 88].