title: Endothelial colony-forming cells from preterm infants are increased and more susceptible to hyperoxia.
abstract: BACKGROUND
  Preterm birth and hyperoxic exposure increase the risk for bronchopulmonary dysplasia (BPD), a chronic lung disease characterized by impaired vascular and alveolar growth. Endothelial progenitor cells, such as self-renewing highly proliferative endothelial colony-forming cells (ECFCs), may participate in vascular repair. The effect of hyperoxia on ECFC growth is unknown.
  
  
  OBJECTIVE
  We hypothesize that umbilical cord blood (CB) from premature infants contains more ECFCs with greater growth potential than term CB. However, preterm ECFCs may be more susceptible to hyperoxia.
  
  
  METHODS
  ECFC colonies were quantified by established methods and characterized by immunohistochemistry and flow cytometry. Growth kinetics were assessed in room air and hyperoxia (FI(O(2)) = 0.4).
  
  
  RESULTS
  Preterm CB (28-35 wk gestation) yielded significantly more ECFC colonies than term CB. Importantly, we found that CD45(-)/CD34(+)/CD133(+)/VEGFR-2(+) cell number did not correlate with ECFC colony count. Preterm ECFCs demonstrated increased growth compared with term ECFCs. Hyperoxia impaired growth of preterm but not term ECFCs. Treatment with superoxide dismutase and catalase enhanced preterm ECFC growth during hyperoxia.
  
  
  CONCLUSIONS
  Preterm ECFCs appear in increased numbers and proliferate more rapidly but have an increased susceptibility to hyperoxia compared with term ECFCs. Antioxidants protect preterm ECFCs from hyperoxia.
authors.affiliation: Pediatric Heart Lung Center, University of Colorado, Denver School of Medicine, Aurora, CO 80045, USA. christopher.baker@uchsc.edu
authors.forename: Christopher D
authors.initials: CD
authors.lastname: Baker
authors.forename: Sharon L
authors.initials: SL
authors.lastname: Ryan
authors.forename: David A
authors.initials: DA
authors.lastname: Ingram
authors.forename: Gregory J
authors.initials: GJ
authors.lastname: Seedorf
authors.forename: Steven H
authors.initials: SH
authors.lastname: Abman
authors.forename: Vivek
authors.initials: V
authors.lastname: Balasubramaniam
mesh_terms: D000975:Antioxidants / Q000627:therapeutic use; D042783:Endothelial Cells / Q000187:drug effects / Q000378:metabolism*; D005312:Fetal Blood / Q000378:metabolism; D006801:Humans; D018496:Hyperoxia / Q000097:blood*; D007231:Infant, Newborn; D007234:Infant, Premature / Q000097:blood* / Q000254:growth & development; D013234:Stem Cells / Q000187:drug effects / Q000378:metabolism*
chemical_list: D000975:Antioxidants