ROS Signaling in Endothelial Function

The vascular endothelium (inner lining of cells in blood vessels) normally prevents
vasospasm and thrombosis by producing nitric oxide and other regulatory substances. In
patients with atherosclerosis, endothelial function is impaired. Excess production of
reactive oxygen species (free radicals) contribute to endothelial dysfunction in
atherosclerosis, and some prior studies have shown a beneficial effect of antioxidant
treatment on endothelial function in patients with coronary artery disease. On the other
hand, reactive oxygen species may be required for normal endothelial function and
antioxidant supplements failed to show a benefit in large clinical trials. The effect of
antioxidant treatment on endothelial function in healthy subjects is unknown. The present
study will test the hypothesis that scavenging reactive species might reduce
endothelium-dependent vasodilation in healthy subjects.

The study is a randomized, double-blind, placebo-controlled crossover study. Participants
will receive 2.4 grams of oral NAC or similar-appearing placebo during the first visit, and
then will cross over to the alternative treatment (NAC or placebo) for the second and final
visit. We will examine endothelial function before and after treatment on each visit.