This Article Full Text Full Text (PDF) Online Supplement All Versions of this Article: 200508-1223OCv1 173/8/897    most recent Alert me when this article is cited Alert me if a correction is posted Services Similar articles in this journal Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via Google Scholar Google Scholar Articles by Grebe, M. Articles by Schulz, R. Search for Related Content PubMed PubMed Citation Articles by Grebe, M. Articles by Schulz, R.

Antioxidant Vitamin C Improves Endothelial Function in Obstructive Sleep Apnea

Divisions of Cardiology and Angiology and Pulmonary and Critical Care Medicine, Department of Internal Medicine, Justus-Liebig-University, Gießen, Germany

Correspondence and requests for reprints should be addressed to Mathias Grebe, M.D., Division of Cardiology and Angiology, Department of Internal Medicine, Justus-Liebig University, Klinikstr. 36, 35392 Gießen, Germany. E-mail: mathias.grebe{at}innere.med.uni-giessen.de

Rationale: Obstructive sleep apnea (OSA) is associated with oxidative stress, endothelial dysfunction, and increased cardiovascular morbidity and mortality.

Objective: We tested the hypothesis that endothelial dysfunction in patients with OSA is linked to oxidative stress.

Methods: In the present study, we measured flow-mediated dilation (FMD) of the brachial artery by ultrasound in 10 otherwise healthy, untreated patients with OSA and 10 age-and sex-matched control subjects without sleep-disordered breathing before and after intravenous injection of the antioxidant vitamin C. The investigator performing the FMD measurements was blinded to the status of the patients.

Results: When compared with control subjects, baseline FMD was significantly reduced in the patients with OSA. After intravenous injection of 0.5 g vitamin C, vasoreactivity remained unchanged in the control subjects. In the patients with OSA, ascorbate led to an increase in FMD to a level comparable to that observed in the control group.

Conclusion: The reduced endothelial-dependent vasodilation in untreated patients with OSA acutely improves by the free radical scavenger vitamin C. These results are in favor of oxidative stress being responsible for the endothelial dysfunction in OSA. Antioxidant strategies should be explored for the treatment of OSA-related cardiovascular disease.

Key Words: cardiovascular disease • endothelial dysfunction • obstructive sleep apnea • oxidative stress

This article has been cited by other articles:

				M D Cross, N L Mills, M Al-Abri, R Riha, M Vennelle, T W Mackay, D E Newby, and N J Douglas Continuous positive airway pressure improves vascular function in obstructive sleep apnoea/hypopnoea syndrome: a randomised controlled trial Thorax, July 1, 2008; 63(7): 578 - 583. [Abstract] [Full Text] [PDF]

				S. Jelic, M. Padeletti, S. M. Kawut, C. Higgins, S. M. Canfield, D. Onat, P. C. Colombo, R. C. Basner, P. Factor, and T. H. LeJemtel Inflammation, Oxidative Stress, and Repair Capacity of the Vascular Endothelium in Obstructive Sleep Apnea Circulation, April 29, 2008; 117(17): 2270 - 2278. [Abstract] [Full Text] [PDF]

				D. Gozal and L. Kheirandish-Gozal Cardiovascular Morbidity in Obstructive Sleep Apnea: Oxidative Stress, Inflammation, and Much More Am. J. Respir. Crit. Care Med., February 15, 2008; 177(4): 369 - 375. [Abstract] [Full Text] [PDF]

				C. Selmi, N. Montano, R. Furlan, C. L. Keen, and M. E. Gershwin Inflammation and Oxidative Stress in Obstructive Sleep Apnea Syndrome Experimental Biology and Medicine, December 1, 2007; 232(11): 1409 - 1413. [Abstract] [Full Text] [PDF]

				P. N. Ainslie, A. Barach, K. J. Cummings, C. Murrell, M. Hamlin, and J. Hellemans Cardiorespiratory and cerebrovascular responses to acute poikilocapnic hypoxia following intermittent and continuous exposure to hypoxia in humans J Appl Physiol, May 1, 2007; 102(5): 1953 - 1961. [Abstract] [Full Text] [PDF]

				R. L. Horner and T. D. Bradley Update in Sleep and Control of Ventilation 2006 Am. J. Respir. Crit. Care Med., March 1, 2007; 175(5): 426 - 431. [Full Text] [PDF]