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.