title: Combined intermittent hypoxia and surface muscle electrostimulation as a method to increase peripheral blood progenitor cell concentration.
abstract: BACKGROUND
  Our goal was to determine whether short-term intermittent hypoxia exposure, at a level well tolerated by healthy humans and previously shown by our group to increase EPO and erythropoiesis, could mobilize hematopoietic stem cells (HSC) and increase their presence in peripheral circulation.
  
  
  METHODS
  Four healthy male subjects were subjected to three different protocols: one with only a hypoxic stimulus (OH), another with a hypoxic stimulus plus muscle electrostimulation (HME) and the third with only muscle electrostimulation (OME). Intermittent hypobaric hypoxia exposure consisted of only three sessions of three hours at barometric pressure 540 hPa (equivalent to an altitude of 5000 m) for three consecutive days, whereas muscular electrostimulation was performed in two separate periods of 25 min in each session. Blood samples were obtained from an antecubital vein on three consecutive days immediately before the experiment and 24 h, 48 h, 4 days and 7 days after the last day of hypoxic exposure.
  
  
  RESULTS
  There was a clear increase in the number of circulating CD34+ cells after combined hypobaric hypoxia and muscular electrostimulation. This response was not observed after the isolated application of the same stimuli.
  
  
  CONCLUSIONS
  Our results open a new application field for hypobaric systems as a way to increase efficiency in peripheral HSC collection.
authors.affiliation: Departament de Fisiologia-Biologia, Universitat de Barcelona, Av. Diagonal 645, E-08028 Barcelona, Spain. gviscor@ub.edu
authors.forename: Ginés
authors.initials: G
authors.lastname: Viscor
authors.forename: Casimiro
authors.initials: C
authors.lastname: Javierre
authors.forename: Teresa
authors.initials: T
authors.lastname: Pagès
authors.forename: Josep-Lluis
authors.initials: JL
authors.lastname: Ventura
authors.forename: Antoni
authors.initials: A
authors.lastname: Ricart
authors.forename: Gregorio
authors.initials: G
authors.lastname: Martin-Henao
authors.forename: Carmen
authors.initials: C
authors.lastname: Azqueta
authors.forename: Ramon
authors.initials: R
authors.lastname: Segura
mesh_terms: D018952:Antigens, CD34 / Q000378:metabolism; D004558:Electric Stimulation; D006412:Hematopoietic Stem Cells / Q000378:metabolism*; D006801:Humans; D000860:Hypoxia / Q000097:blood*; D007962:Leukocytes / Q000166:cytology / Q000378:metabolism; D008214:Lymphocytes / Q000166:cytology / Q000378:metabolism; D008297:Male; D008875:Middle Aged; D018482:Muscle, Skeletal / Q000378:metabolism*
chemical_list: D018952:Antigens, CD34