title: Vascular reactivity and biomarkers of endothelial function in healthy subjects exposed to acute hypobaric hypoxia.
abstract: OBJECTIVE
  The aim of this study was to evaluate the effects of acute hypobaric hypoxia (HH) on vascular reactivity and biochemical markers associated with endothelial function (EF).
  
  
  METHODS
  Ten healthy subjects were exposed to a simulated altitude of 4,000 meters above sea level for 4 hours in a hypobaric chamber. Vascular reactivity was measured by the flow-mediated vasodilatation (FMVD) test. Endothelin-1, high sensitive-C reactive protein (hsCRP), vascular cell adhesion molecule 1, interleukin-6 (IL-6), tumor necrosis factor-α (TNF-α), paraoxonase and adiponectin levels, and FMVD were evaluated before and after the exposure.
  
  
  RESULTS
  Subjects were young (age: 32±6 years), lean [body mass index: 23.9±2.0kg/m(2), waist circumference: 77(IQR: 72-80) cm], and presented normal clinical and biochemical parameters. No significant changes were evidenced in FMVD in response to HH (pre: 0.45 (0.20-0.70) vs. during: 0.50 (0.20-1.22) mm; p=0.594). On the other hand, endothelin-1 (+54%, p<0.05), hsCRP (+37%, p<0.001), IL-6 (+75%, p<0.05), TNF-α (+75%, p<0.05), and adiponectin (-39%, p<0.01) levels were significantly altered post-HH. FMVD was increased in 7 subjects, and it was decreased in 3 individuals during HH exposure. Interestingly, when EF biomarkers were compared between these two subgroups of subjects, only post exposure-adiponectin levels were significantly different (49±5 vs. 38±6μg/ml, respectively, p<0.05).
  
  
  CONCLUSIONS
  HH exposure had an effect on endothelin-1, adiponectin, hsCRP, IL-6, and TNF-α concentration. However, adiponectin was the only biomarker associated with an altered vascular reactivity.
authors.affiliation: Argentine Society of Mountain Medicine, Argentina; School of Pharmacy and Biochemistry, University of Buenos Aires, CONICET, Buenos Aires, Argentina; Italian Hospital, Buenos Aires, Argentina.
authors.forename: Diego
authors.initials: D
authors.lastname: Iglesias
authors.affiliation: School of Pharmacy and Biochemistry, University of Buenos Aires, CONICET, Buenos Aires, Argentina. Electronic address: mulag@hotmail.com.
authors.forename: Leonardo
authors.initials: L
authors.lastname: Gómez Rosso
authors.affiliation: Italian Hospital, Buenos Aires, Argentina.
authors.forename: Nora
authors.initials: N
authors.lastname: Vainstein
authors.affiliation: School of Pharmacy and Biochemistry, University of Buenos Aires, CONICET, Buenos Aires, Argentina.
authors.forename: Tomás
authors.initials: T
authors.lastname: Meroño
authors.affiliation: Argentine Society of Mountain Medicine, Argentina.
authors.forename: Christian
authors.initials: C
authors.lastname: Lezón
authors.affiliation: School of Pharmacy and Biochemistry, University of Buenos Aires, CONICET, Buenos Aires, Argentina.
authors.forename: Fernando
authors.initials: F
authors.lastname: Brites
mesh_terms: D052242:Adiponectin / Q000378:metabolism; D000328:Adult; D043303:Aryldialkylphosphatase / Q000378:metabolism; D015415:Biomarkers / Q000378:metabolism*; D002097:C-Reactive Protein / Q000378:metabolism; D019332:Endothelin-1 / Q000378:metabolism; D004730:Endothelium, Vascular / Q000378:metabolism* / Q000502:physiology*; D064368:Healthy Volunteers; D006801:Humans; D000860:Hypoxia / Q000378:metabolism* / Q000503:physiopathology*; D015850:Interleukin-6 / Q000378:metabolism; D008297:Male; D014409:Tumor Necrosis Factor-alpha / Q000378:metabolism; D019010:Vascular Cell Adhesion Molecule-1 / Q000378:metabolism; D014664:Vasodilation / Q000502:physiology; D055815:Young Adult
chemical_list: D052242:Adiponectin; D015415:Biomarkers; D019332:Endothelin-1; C508600:IL6 protein, human; D015850:Interleukin-6; D014409:Tumor Necrosis Factor-alpha; D019010:Vascular Cell Adhesion Molecule-1; D002097:C-Reactive Protein; D043303:Aryldialkylphosphatase
keywords: Adiponectin; Cytokines; Endothelial function; Endothelin-1; Hypobaric hypoxia; Hypoxia