Oxidative-Nitrosative Stress and Systemic Vascular Function in Highlanders With and Without Exaggerated Hypoxemia

Methods: Oxidative-nitrosative stress (as determined by the presence of the biomarkers ascorbate radical [A(center dot-)], via electron paramagnetic resonance spectroscopy, and nitrite [NO2-], via ozone-based chemiluminescence) was assessed in venous blood of 25 male highlanders in Bolivia living at 3,600 m with CMS (n = 13, CMS+) and without CMS (n = 12, CMS). Twelve age- and activity-matched, healthy, male lowlanders were examined at sea level and during acute hypoxia. We also measured flow-mediated dilatation (FMD), arterial stiffness defined by augmentation index normalized for a heart rate of 75 beats/min (AIx-75), and carotid intima-media thickness (IMT).

Background: Acute exposure to high altitude stimulates free radical formation in lowlanders, yet whether this persists during chronic exposure in healthy, well-adapted and maladapted highlanders suffering from chronic mountain sickness (CMS) remains to be established.