Why arenâ€™t antioxidants magic cure-alls?
Itâ€™s not a silly question, when one sees how oxidative stress and reactive oxygen species have been implicated in so many diseases, ranging from hypertension and atherosclerosis to neurodegenerative disorders. Yet large-scale clinical trials supplementing participantsâ€™ diets with antioxidants have showed little benefit.
Emory University School of Medicine scientists have arrived at an essential insight: the cell isnâ€™t a tiny bucket with all the constituent chemicals sloshing around. To modulate reactive oxygen species effectively, an antioxidant needs to be targeted to the right place in the cell.
Sergei Dikalov and colleagues in the Division of Cardiology have a paper in the July 9 issue ofÂ Circulation Research, describing how targeting antioxidant molecules to mitochondria dramatically increases their effectiveness in tamping down hypertension.
Mitochondria are usually described as miniature power plants, but in the cells that line blood vessels, they have the potential to act as amplifiers. The authors describe a â€œvicious cycleâ€ of feedback between the cellular enzyme NADPH oxidase, which produces the reactive form of oxygen called superoxide, and the mitochondria, which can also make superoxide as a byproduct of their energy-producing function.