Chronic antioxidant use and changes in endothelial dysfunction: a review of clinical investigations

There are tremendous clinical interest and speculation about the impact of reversing endothelial dysfunction. This paper reviews information from patient studies that have assessed the effect of chronic antioxidant use on endothelial dysfunction. A search of MEDLINE and Current Contents online, complemented by detailed analysis of references in the papers identified, was used to identify all studies pertaining to patients treated with oral antioxidants to modify endothelial dysfunction. Studies of single acute doses were excluded. Endothelium-mediated end points were vascular responses in conduit or resistance vessels, endothelial cell-monocyte interaction and measures of soluble adhesion molecules. Positive effects on conduit vessel dilation, endothelial cell-monocyte interactions and soluble adhesion molecules were common. Except for one study, negative effects were noted in resistance vessels. Further trials are required to clarify and define the impact of these findings on clinical outcome.