title: Hypoxic exercise training improves cardiac/muscular hemodynamics and is associated with modulated circulating progenitor cells in sedentary men.
abstract: BACKGROUND
  Circulating progenitor cells (CPCs) improve cardiovascular function and organ perfusion by enhancing the capacities of endothelial repair and neovasculogenesis. This study investigates whether exercise regimens with/without hypoxia affect cardiac and muscular hemodynamics by modulating CPCs and angiogenic factors.
  
  
  METHODS
  Forty sedentary males were randomly divided into hypoxic (HT, n=20) and normoxic (NT, n=20) training groups. The subjects were trained on a bicycle ergometer at 60%VO(2max) under 15% (HT) or 21% (NT) O2 conditions for 30 min daily, five days weekly for five weeks.
  
  
  RESULTS
  After the five-week interventions, the HT group exhibited a larger improvement in aerobic capacity than the NT group. Furthermore, the HT regimen (i) enhanced cardiac output (Q(H)) and perfusion (Q(M))/oxygenation of vastus lateralis during exercise; (ii) increased levels of CD34(+)/KDR(+)/CD117(+), CD34(+)/KDR(+)/CD133(+), and CD34(+)/KDR(+)/CD31(+) cells in blood; (iii) promoted the proliferative capacity of these CPC subsets, and (iv) elevated plasma nitrite/nitrate, stromal cell-derived factor-1 (SDF-1), matrix metalloproteinase-9 (MMP-9), and vascular endothelial growth factor-A (VEGF-A) concentrations. Despite the lack of changes in Q(H) and the number or proliferative capacity of CD34(+)/KDR(+)/CD117(+) or CD34(+)/KDR(+)/CD31(+) cells, the NT regimen elevated both Q(M) and plasma nitrite/nitrate levels and suppressed the shedding of endothelial cells (CD34(-)/KDR(+)/phosphatidylserine(+) cells).
  
  
  CONCLUSIONS
  The HT regimen improves cardiac and muscular hemodynamic adaptations, possibly by promoting the mobilization/function of CPCs and the production of angiogenic factors.
authors.affiliation: Healthy Aging Research Center, Graduate Institute of Rehabilitation Science, Chang Gung University, Tao-Yuan, Taiwan; Heart Failure Center, Chang Gung Memorial Hospital, Keeling, Taiwan. Electronic address: s5492@mail.cgu.edu.tw.
authors.forename: Jong-Shyan
authors.initials: JS
authors.lastname: Wang
authors.affiliation: Healthy Aging Research Center, Graduate Institute of Rehabilitation Science, Chang Gung University, Tao-Yuan, Taiwan.
authors.forename: Mei-Yi
authors.initials: MY
authors.lastname: Lee
authors.affiliation: Healthy Aging Research Center, Graduate Institute of Rehabilitation Science, Chang Gung University, Tao-Yuan, Taiwan.
authors.forename: Hen-Yu
authors.initials: HY
authors.lastname: Lien
authors.affiliation: Healthy Aging Research Center, Graduate Institute of Rehabilitation Science, Chang Gung University, Tao-Yuan, Taiwan.
authors.forename: Tzu-Pin
authors.initials: TP
authors.lastname: Weng
mesh_terms: D002320:Cardiovascular Physiological Phenomena; D054377:Chemokine CXCL12 / Q000097:blood; D004730:Endothelium, Vascular / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005080:Exercise Test; D064368:Healthy Volunteers; D006321:Heart / Q000502:physiology*; D006412:Hematopoietic Stem Cells / Q000166:cytology / Q000502:physiology*; D006439:Hemodynamics / Q000502:physiology*; D006801:Humans; D000860:Hypoxia / Q000503:physiopathology*; D008297:Male; D020780:Matrix Metalloproteinase 9 / Q000097:blood; D018482:Muscle, Skeletal / Q000502:physiology; D009566:Nitrates / Q000097:blood; D009573:Nitrites / Q000097:blood; D010100:Oxygen / Q000008:administration & dosage / Q000097:blood; D010101:Oxygen Consumption / Q000502:physiology; D057185:Sedentary Behavior; D013318:Stroke Volume / Q000502:physiology; D042461:Vascular Endothelial Growth Factor A / Q000097:blood; D055815:Young Adult
chemical_list: C515255:CXCL12 protein, human; D054377:Chemokine CXCL12; D009566:Nitrates; D009573:Nitrites; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; C579270:MMP9 protein, human; D020780:Matrix Metalloproteinase 9; D010100:Oxygen
keywords: Circulating progenitor cells; Exercise; Hemodynamics; Hypoxia