title: Assessment of cellular and plasma oxidative stress in SAHS patients before and after continuous positive airway pressure treatment.
abstract: BACKGROUND
  Several indirect techniques have been used for measuring oxidative stress in sleep apnoea-hypopnoea syndrome (SAHS) patients. The purpose of this study was to find out if both, cellular or plasma oxidative stress evaluations, are good estimators to assess oxidative stress in SAHS patients before and after one month's CPAP treatment.
  
  
  METHODS
  The study included 28 SAHS patients requiring CPAP treatment and 15 healthy control subjects. Plasma and serum oxidative stress biomarkers (lipid peroxidation, total antioxidant capacity, and the activities of glutathione peroxidase, glutathione reductase, glutathione s-transferase, catalase and superoxide dismutase) were measured using commercial kits. Cellular oxidative stress biomarkers (mitochondrial membrane potential, intracellular glutathione, superoxide anion, and hydrogen peroxide) were analysed by flow cytometry. The Wilcoxon test for paired samples was used to compare oxidative stress and clinical parameters in patients before and after treatment with CPAP. Relationships in oxidative stress markers between controls and patients were analyzed using the Mann-Whitney U test. The Spearman correlation coefficient was calculated to estimate the linear correlations between variables.
  
  
  RESULTS
  Oxidative stress was notably decreased after CPAP. Before CPAP, SAHS severity positively correlated with hydrogen peroxide levels, while negative correlations were observed between SAHS severity and plasma TAC in patients. Also, plasma glutathione peroxidase activity negatively correlated with cellular superoxide anion, while plasma superoxide dismutase activity positively correlated with intracellular glutathione. After CPAP, plasma TAC and glutathione peroxidase activity negatively correlated with cellular hydrogen peroxide and superoxide anion.
  
  
  CONCLUSIONS
  In conclusion, this study seems to confirm that plasma and cellular assessment reflect, in the same way, the oxidative stress status of the studied patients. Furthermore, plasma total antioxidant capacity as well as cellular hydrogen peroxide levels can be good markers for assessing oxidative stress in SAHS patients.
authors.affiliation: Servicio de Endocrinología y Nutrición, Hospital Clínico Universitario Virgen de la Victoria, 29010 Málaga, Spain. moramurri@gmail.com
authors.forename: M
authors.initials: M
authors.lastname: Murri
authors.forename: R
authors.initials: R
authors.lastname: Garcia-Delgado
authors.forename: J
authors.initials: J
authors.lastname: Alcázar-Ramirez
authors.forename: F
authors.initials: F
authors.lastname: Linde
authors.forename: A
authors.initials: A
authors.lastname: Fernández-Ramos
authors.forename: F
authors.initials: F
authors.lastname: Cardona
authors.forename: F J
authors.initials: FJ
authors.lastname: Tinahones
mesh_terms: D000328:Adult; D000975:Antioxidants / Q000378:metabolism; D015415:Biomarkers / Q000097:blood; D001782:Blood Donors; D045422:Continuous Positive Airway Pressure; D005979:Glutathione Peroxidase / Q000097:blood; D005982:Glutathione Transferase / Q000097:blood; D006801:Humans; D015227:Lipid Peroxidation; D008297:Male; D008875:Middle Aged; D018384:Oxidative Stress; D017286:Polysomnography; D017382:Reactive Oxygen Species / Q000378:metabolism; D012016:Reference Values; D013345:Subarachnoid Hemorrhage / Q000097:blood* / Q000628:therapy*; D013482:Superoxide Dismutase / Q000097:blood
chemical_list: D000975:Antioxidants; D015415:Biomarkers; D017382:Reactive Oxygen Species; D005979:Glutathione Peroxidase; D013482:Superoxide Dismutase; D005982:Glutathione Transferase