PT  - JOURNAL ARTICLE
AU  - John R. Stradling
AU  - Esther I. Schwarz
AU  - Christian Schlatzer
AU  - Ari R. Manuel
AU  - Regent Lee
AU  - Charalambos Antoniades
AU  - Malcolm Kohler
TI  - Biomarkers of oxidative stress following continuous positive airway pressure withdrawal: data from two randomised trials
AID  - 10.1183/09031936.00023215
DP  - 2015 Oct 01
TA  - European Respiratory Journal
PG  - 1065--1071
VI  - 46
IP  - 4
4099  - http://erj.ersjournals.com/content/46/4/1065.short
4100  - http://erj.ersjournals.com/content/46/4/1065.full
SO  - Eur Respir J2015 Oct 01; 46
AB  - There is conflicting evidence whether intermittent hypoxia in obstructive sleep apnoea (OSA) influences oxidative stress. We hypothesised that withdrawal of continuous positive airway pressure (CPAP) from patients with OSA would raise markers of oxidative stress.59 patients with CPAP-treated moderate-to-severe OSA (oxygen desaturation index (ODI) >20 events·h−1) were randomised 1:1 to either stay on CPAP (n=30) or change to sham CPAP (n=29) for 2 weeks. Using samples from two similar studies at two sites, we measured early morning blood malondialdehyde (MDA, a primary outcome in one study and a secondary outcome in the other), lipid hydroperoxides, total antioxidant capacity, superoxide generation from mononuclear cells and urinary F2-isoprostane. We also measured superoxide dismutase as a marker of hypoxic preconditioning. “Treatment” effects (sham CPAP versus CPAP) were calculated via linear regression.Sham CPAP provoked moderate-to-severe OSA (mean ODI 46 events·h−1), but blood markers of oxidative stress did not change significantly (MDA “treatment” effect (95% CI) −0.02 (−0.23 to +0.19) μmol·L−1). Urinary F2-isoprostane fell significantly by ∼30% (−0.26 (−0.42 to −0.10) ng·mL−1) and superoxide dismutase increased similarly (+0.17 (+0.02 to +0.30) ng·mL−1).We found no direct evidence of increased oxidative stress in patients experiencing a return of their moderate-to-severe OSA. The fall in urinary F2-isoprostane and rise in superoxide dismutase implies that hypoxic preconditioning may have reduced oxidative stress.Obstructive sleep apnoea may induce hypoxic preconditioning and reduce, rather than increase, oxidative stress http://ow.ly/MaUoN