Plasma levels of retinoids, carotenoids and tocopherols in patients with mild obstructive sleep apnoea.
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.
Day
Regina M
RM
Department of Pharmacology, Uniformed Services University of the Health Sciences, Bethesda, MD 20814-4799, USA. rday@usuhs.mil
Matus
Ismael A
IA
Suzuki
Yuichiro J
YJ
Yeum
Kyung-Jin
KJ
Qin
Jian
J
Park
Ah-Mee
AM
Jain
Vivek
V
Kuru
Tunay
T
Tang
Guangwen
G
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
D000975:Antioxidants; D015415:Biomarkers; D012176:Retinoids; D002338:Carotenoids; D024505:Tocopherols