Inflammation, oxidative stress, and the vascular endothelium in obstructive sleep apnea

Obstructive sleep apnea (OSA) affects 25% of the Western adult population. It is an independent but seldom-recognized risk factor for hypertension, myocardial infarction, stroke, and increased mortality. Patients with OSA experience repetitive episodes of hypoxia/reoxygenation during transient cessation of breathing that promote systemic oxidative stress and inflammation. Vascular endothelial inflammation and enhanced oxidative stress that are reversible with therapy for OSA were recently demonstrated directly in patients with OSA who were free of overt cardiovascular conditions. Vascular endothelial inflammation and enhanced oxidative stress may in part explain the accelerated progression of atherosclerosis in patients with untreated OSA. The present review will focus on indirect and direct evidence of vascular endothelial inflammation and enhanced oxidative stress in patients with OSA. The potential utility of venous endothelial biopsy technique in evaluating the mechanisms that mediate the effects of systemic conditions such as diabetes mellitus, sleep apnea, and obesity on the vascular endothelium will also be discussed.