title: Obstructive sleep apnea causes oxidative damage to plasma lipids and proteins and decreases adiponectin levels.
abstract: PUPOSE: Obstructive sleep apnea (OSA) is associated with various metabolic disorders, and oxidative stress was suggested to play an important role. In the present study, we aimed to investigate serum adiponectin and oxidative stress markers, especially protein carbonyls, and to evaluate the correlation between these parameters and lipid, insulin and fasting glucose concentrations in OSA patients and controls.
  
  
  METHODS
  Blood was drawn from healthy male volunteers following full-night polysomnographic evaluation. Subjects were classified as controls (n = 24), mild OSA group (n = 9) and moderate-severe OSA group (n = 17) according to their apnea-hypopnea indices (AHIs). Serum lipids, fasting glucose, adiponectin, malondialdehyde (MDA), protein carbonyl concentrations, and paraoxonase activities were measured in all subjects.
  
  
  RESULTS
  Results of this study indicated that serum adiponectin concentrations were significantly decreased and MDA and protein carbonyl concentrations were significantly elevated in OSA patients compared to the controls. Protein carbonyl and MDA concentrations were significantly and positively correlated with AHI, while a significant negative correlation was found between adiponectin concentrations and AHI. Adiponectin levels were negatively correlated with MDA levels.
  
  
  CONCLUSIONS
  Results of this study, which is the first human study investigating and describing serum protein carbonyl concentrations in OSA patients, reveal that OSA causes increments in oxidative damage and decreases adiponectin levels. The recurrent hypoxia-reoxygenation attacks in OSA patients may activate oxidative stress, elevating sympathetic activity and leading to low levels of adiponectin.
authors.affiliation: Department of Biochemistry, Uludag University, Bursa, Turkey.
authors.forename: Ebru
authors.initials: E
authors.lastname: Vatansever
authors.forename: Esma
authors.initials: E
authors.lastname: Surmen-Gur
authors.forename: Ahmet
authors.initials: A
authors.lastname: Ursavas
authors.forename: Mehmet
authors.initials: M
authors.lastname: Karadag
mesh_terms: D052242:Adiponectin / Q000097:blood*; D000328:Adult; D001786:Blood Glucose / Q000378:metabolism; D001798:Blood Proteins / Q000378:metabolism*; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D008055:Lipids / Q000097:blood*; D008297:Male; D008315:Malondialdehyde / Q000097:blood; D008875:Middle Aged; D018384:Oxidative Stress / Q000502:physiology*; D017286:Polysomnography; D050050:Protein Carbonylation / Q000502:physiology; D020181:Sleep Apnea, Obstructive / Q000503:physiopathology*; D013223:Statistics as Topic; D013564:Sympathetic Nervous System / Q000503:physiopathology
chemical_list: D052242:Adiponectin; D001786:Blood Glucose; D001798:Blood Proteins; D007328:Insulin; D008055:Lipids; D008315:Malondialdehyde