Circulation
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Randomized Controlled Trial Clinical Trial
Xanthine oxidase inhibition reverses endothelial dysfunction in heavy smokers.
Cigarette smoking causes endothelial dysfunction, possibly through increased oxidant stress. The enzyme xanthine oxidase produces oxidative free radicals. We tested the hypothesis that xanthine oxidase contributes to endothelial dysfunction in cigarette smokers by administering the inhibitor allopurinol. ⋯ Smoking-induced endothelial dysfunction of resistance vessels is rapidly reversed with oral allopurinol. These data suggest that xanthine oxidase contributes importantly to endothelial dysfunction caused by cigarette smoking.