title: Plasma levels of retinoids, carotenoids and tocopherols in patients with mild obstructive sleep apnoea.
abstract: OBJECTIVE
  OSA is associated with increased incidence of cardiovascular diseases. Pathogenic mechanisms of vascular diseases include thickened vascular walls due to the increased number of smooth muscle cells (SMC). Retinoic acid (RA) suppresses the growth of SMC, and reduced retinoid levels are associated with vascular diseases. Oxidant signalling promotes SMC growth, thus antioxidant levels may also influence the development of cardiovascular diseases. The present study tested the hypothesis that plasmas from OSA patients contain altered levels of retinoids, carotenoids and tocopherols.
  
  
  METHODS
  Plasma samples were taken before and after sleep from patients with OSA (mostly mild) without known cardiovascular diseases and from control subjects. Levels of retinoids, carotenoids and tocopherols were measured using sensitive gas chromatograph-mass spectrometry and high pressure liquid chromatography methods and total antioxidant capacity was assessed fluorometrically.
  
  
  RESULTS
  Results showed that plasmas from patients with OSA had significantly lower retinyl palmitate and 9-cis RA compared with control subjects, while levels of retinol, all-trans RA and 13-cis RA were indifferent. All-transbeta-carotene and 9-cisbeta-carotene were also lower in OSA patients. Levels of all-trans RA and 13-cis RA in OSA patients were reduced after sleep compared with before sleep. OSA patients showed significantly higher delta-tocopherol compared with controls. Treatment of cultured human vascular SMC with post-sleep OSA patient plasmas promoted cell growth, but not in controls.
  
  
  CONCLUSIONS
  Mild OSA exhibits altered levels of specific retinoids, carotenoids and tocopherols, which may be markers and/or mediators for the increased susceptibility of patients to vascular diseases.
authors.affiliation: Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799, USA. rday@usuhs.mil
authors.forename: Regina M
authors.initials: RM
authors.lastname: Day
authors.forename: Ismael A
authors.initials: IA
authors.lastname: Matus
authors.forename: Yuichiro J
authors.initials: YJ
authors.lastname: Suzuki
authors.forename: Kyung-Jin
authors.initials: KJ
authors.lastname: Yeum
authors.forename: Jian
authors.initials: J
authors.lastname: Qin
authors.forename: Ah-Mee
authors.initials: AM
authors.lastname: Park
authors.forename: Vivek
authors.initials: V
authors.lastname: Jain
authors.forename: Tunay
authors.initials: T
authors.lastname: Kuru
authors.forename: Guangwen
authors.initials: G
authors.lastname: Tang
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000378:metabolism; D015415:Biomarkers / Q000097:blood; D002338:Carotenoids / Q000097:blood*; D016022:Case-Control Studies; D049109:Cell Proliferation; D002478:Cells, Cultured; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009131:Muscle, Smooth, Vascular / Q000473:pathology; D018384:Oxidative Stress / Q000502:physiology; D011446:Prospective Studies; D012176:Retinoids / Q000097:blood*; D012189:Retrospective Studies; D012307:Risk Factors; D012720:Severity of Illness Index; D020181:Sleep Apnea, Obstructive / Q000097:blood* / Q000503:physiopathology; D024505:Tocopherols / Q000097:blood*; D014652:Vascular Diseases / Q000453:epidemiology
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D012176:Retinoids; D002338:Carotenoids; D024505:Tocopherols