title: Effects of 8 weeks of CPAP on lipid-based oxidative markers in obstructive sleep apnea: a randomized trial.
abstract: Dyslipidaemia and increased oxidative stress have been reported in severe obstructive sleep apnea, and both may be related to the development of cardiovascular disease. We have previously shown in a randomized crossover study in patients with moderate to severe obstructive sleep apnea that therapeutic continuous positive airway pressure treatment for 8 weeks improved postprandial triglycerides and total cholesterol when compared with sham continuous positive airway pressure. From this study we have now compared the effect of 8 weeks of therapeutic continuous positive airway pressure and sham continuous positive airway pressure on oxidative lipid damage and plasma lipophilic antioxidant levels. Unesterified cholesterol, esterified unsaturated fatty acids (cholesteryl linoleate: C18:2; and cholesteryl arachidonate: C20:4; the major unsaturated and oxidizable lipids in low-density lipoproteins), their corresponding oxidized products [cholesteryl ester-derived lipid hydroperoxides and hydroxides (CE-O(O)H)] and antioxidant vitamin E were assessed at 20:30 hours before sleep, and at 06:00 and 08:30 hours after sleep. Amongst the 29 patients completing the study, three had incomplete or missing [CE-O(O)H] data. The mean apnea -hypopnoea index, age and body mass index were 38 per hour, 49 years and 32 kg m(-2) , respectively. No differences in lipid-based oxidative markers or lipophilic antioxidant levels were observed between the continuous positive airway pressure and sham continuous positive airway pressure arms at any of the three time-points [unesterified cholesterol 0.01 mm, P > 0.05; cholesteryl linoleate: C18:2 0.05 mm, P > 0.05; cholesteryl arachidonate: C20:4 0.02 mm, P = 0.05; CE-O(O)H 2.5 nm, P > 0.05; and lipid-soluble antioxidant vitamin E 0.03 μm, P > 0.05]. In this study, accumulating CE-O(O)H, a marker of lipid oxidation, does not appear to play a role in oxidative stress in obstructive sleep apnea.
authors.affiliation: Sleep & Circadian Research Group, Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia.|Discipline of Sleep Medicine, Sydney Medical School, The University of Sydney, NSW, Australia.|Department of Respiratory and Sleep Medicine, Royal Prince Alfred Hospital, Camperdown, NSW, Australia.
authors.forename: Sheila
authors.initials: S
authors.lastname: Sivam
authors.affiliation: Discipline of Pathology, Bosch Institute, The University of Sydney, NSW, Australia.
authors.forename: Paul K
authors.initials: PK
authors.lastname: Witting
authors.affiliation: Sleep & Circadian Research Group, Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia.|Discipline of Sleep Medicine, Sydney Medical School, The University of Sydney, NSW, Australia.
authors.forename: Camilla M
authors.initials: CM
authors.lastname: Hoyos
authors.affiliation: Discipline of Pathology, Bosch Institute, The University of Sydney, NSW, Australia.
authors.forename: Aung M
authors.initials: AM
authors.lastname: Maw
authors.affiliation: Sleep & Circadian Research Group, Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia.|Discipline of Sleep Medicine, Sydney Medical School, The University of Sydney, NSW, Australia.|Department of Respiratory and Sleep Medicine, Royal Prince Alfred Hospital, Camperdown, NSW, Australia.
authors.forename: Brendon J
authors.initials: BJ
authors.lastname: Yee
authors.affiliation: Sleep & Circadian Research Group, Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia.|Discipline of Sleep Medicine, Sydney Medical School, The University of Sydney, NSW, Australia.|Department of Respiratory and Sleep Medicine, Royal Prince Alfred Hospital, Camperdown, NSW, Australia.
authors.forename: Ronald R
authors.initials: RR
authors.lastname: Grunstein
authors.affiliation: Sleep & Circadian Research Group, Woolcock Institute of Medical Research, University of Sydney, Sydney, NSW, Australia.|Discipline of Sleep Medicine, Sydney Medical School, The University of Sydney, NSW, Australia.|Department of Respiratory and Sleep Medicine, Royal North Shore Hospital, St Leonards, NSW, Australia.
authors.forename: Craig L
authors.initials: CL
authors.lastname: Phillips
mesh_terms: D000975:Antioxidants / Q000032:analysis*; D015415:Biomarkers / Q000097:blood; D015992:Body Mass Index; D045422:Continuous Positive Airway Pressure; D005260:Female; D006801:Humans; D008055:Lipids / Q000097:blood* / Q000737:chemistry; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D012890:Sleep / Q000502:physiology; D020181:Sleep Apnea, Obstructive / Q000097:blood* / Q000378:metabolism / Q000503:physiopathology / Q000628:therapy*; D013997:Time Factors; D014810:Vitamin E / Q000097:blood
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D008055:Lipids; D014810:Vitamin E
keywords: oxidized lipids