title: Endothelial repair capacity and apoptosis are inversely related in obstructive sleep apnea.
abstract: OBJECTIVE
  To investigate the impact of obstructive sleep apnea (OSA) on endothelial repair capacity and apoptosis in the absence of potentially confounding factors including obesity.
  
  
  METHODS
  Sixteen patients with a body mass index <30 and newly diagnosed OSA and 16 controls were studied. Circulating levels of endothelial progenitor cells, a marker of endothelial repair capacity, and endothelial microparticles, a marker of endothelial apoptosis, were quantified before and after four-week therapy with continuous positive airway pressure (CPAP). Endothelial cell apoptotic rate was also quantified in freshly harvested venous endothelial cells. Vascular reactivity was measured by flow-mediated dilation.
  
  
  RESULTS
  Before treatment, endothelial microparticle levels were greater and endothelial progenitor cell levels were lower in patients with OSA than in controls (P < 0.001 for both). Levels of endothelial microparticles and progenitors cells were inversely related (r = -0.67, P < 0.001). Endothelial progenitor cell levels increased after effective treatment (P = 0.036).
  
  
  CONCLUSIONS
  In the absence of any co-morbid conditions including obesity, OSA alone impairs endothelial repair capacity and promotes endothelial apoptosis. These early endothelial alterations may underlie accelerated atherosclerosis and increased cardiovascular risk in OSA.
authors.affiliation: Division of Pulmonary, Allergy, and Critical Care Medicine, Columbia University College of Physicians and Surgeons, New York, NY 10032, USA. sj366@columbia.edu
authors.forename: Sanja
authors.initials: S
authors.lastname: Jelic
authors.forename: David J
authors.initials: DJ
authors.lastname: Lederer
authors.forename: Tessa
authors.initials: T
authors.lastname: Adams
authors.forename: Margherita
authors.initials: M
authors.lastname: Padeletti
authors.forename: Paolo C
authors.initials: PC
authors.lastname: Colombo
authors.forename: Phillip
authors.initials: P
authors.lastname: Factor
authors.forename: Thierry H
authors.initials: TH
authors.lastname: Le Jemtel
mesh_terms: D000328:Adult; D017209:Apoptosis; D015992:Body Mass Index; D001916:Brachial Artery / Q000503:physiopathology; D002318:Cardiovascular Diseases / Q000209:etiology / Q000473:pathology; D049109:Cell Proliferation; D055252:Cell-Derived Microparticles / Q000473:pathology*; D045422:Continuous Positive Airway Pressure; D042783:Endothelial Cells / Q000473:pathology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000150:complications* / Q000473:pathology / Q000503:physiopathology; D020181:Sleep Apnea, Obstructive / Q000209:etiology / Q000473:pathology / Q000503:physiopathology / Q000628:therapy*; D013234:Stem Cells / Q000473:pathology*; D013997:Time Factors; D016896:Treatment Outcome; D014664:Vasodilation