Long-term Intermittent Hypoxia Injures Brain White Matter

1471 Intermittent Hypoxia Elevates Cobalt Levels in Brain—Veasey et al INTRODUCTION Occurring in 3-5% of adults in developed countries, obstructive sleep apnea (OSA) involves intermittent, sleep state-dependent, brief reductions or cessations in ventilation.1 Each disruption is associated with a partial desaturation of hemoglobin followed by reoxygenation. The brain is particularly vulnerable to hypoxia/reoxygenation, and neuroimaging studies of patients with moderate to severe levels of OSA have revealed brain injury, especially within white matter regions of the forebrain.2-4 Exposure of healthy animals to the patterns of deoxygenation and re-oxygenation in OSA results in the carbonylation of proteins and the peroxidation of membrane lipids, indicating that intermittent hypoxia can cause oxidative stress.5,6 It is thought that the reoxygenation phase involves an increased production of superoxide by mitochondria.6 Although superoxide is normally detoxified by superoxide dismutase, LONG-TERM INTERMITTENT HYPOXIA INJURES BRAIN WHITE MATTER