FMO5 and Hyperglycemia: In cultured human endothelial cells exposed to hyperglycemia for 2 weeks and normoglycemia for a further week, markers of oxidative stress persisted during normoglycemia, but exposure of these cells during the final week to several antioxidants—lipoic acid, oxypurinol, and the NADPH oxidase inhibitor apocynin—diminished this oxidative stress [259].