Effects of Oxygen Administration on the Circulating Vascular Endothelial Growth Factor (VEGF) Levels in Patients with Obstructive Sleep Apnea Syndrome

Abstract

Repeated nocturnal hypoxia is implicated in the pathogenesis of cardiovascular complications in obstructive sleep apnea syndrome (OSAS). We hypothesized that circulating vascular endothelial growth factor (VEGF) levels are affected by nocturnal hypoxemia in patients with OSAS. We examined the serum VEGF levels in patients with OSAS and in control subjects. We also tested the effects of oxygen or air administration on the subjects' VEGF levels. Twenty-four OSAS patients (mean age 54.2 +/- 3.6 years) and 24 age-matched control subjects (53.2 +/- 3.6 years). Their serum samples were tested. Serum VEGF levels at 8:00 AM were significantly higher in OSAS patients than in controls (p<0.01). VEGF levels decreased from 515 +/- 31 (pg/ml) to 178 +/- 16 (pg/m) (p<0.01) in OSAS patients whose nocturnal hypoxemia was found to be improved by administration of 2 l/min of oxygen during the night. However, the administration of compressed air affected neither the VEGF level nor nocturnal oxygen desaturation in OSAS patients. These results indicate that circulating VEGF levels are elevated in OSAS patients, primarily due to nocturnal hypoxemia.