Oxidative stress biomarkers in patients with untreated obstructive sleep apnea syndrome

Background: The pathogenic role of oxidative stress in obstructive sleep apnea syndrome (OSAS) is still a matter of debate, with different studies obtaining contrasting results. Methods: The aim of the present study was to evaluate three well-known markers of oxidative stress (advanced oxidation protein products [AOPP], ferric reducing antioxidant power [FRAP], and total glutathione [GSH]) in a cohort of 41 untreated patients with a new diagnosis of OSAS. Results: We observed that OSAS patients showed increased protein oxidative damage and impaired antioxidant defenses. Patients with more severe OSAS had a lower total antioxidant capability. Preliminary data on a subgroup of patients (n = 7) treated with CPAP show a significant increment of the FRAP values (P < 0.005). Conclusions: Our findings indicate that such oxidative stress markers may be useful to detect and monitor redox imbalance in OSAS. Moreover, FRAP might be a new useful biomarker to monitor in vivo the oxidative response to CPAP therapy. (C) 2012 Elsevier B.V. All rights reserved.