title: Ex vivo expanded human cord blood-derived hematopoietic progenitor cells induce lung growth and alveolarization in injured newborn lungs.
abstract: BACKGROUND
  We investigated the capacity of expanded cord blood-derived CD34+ hematopoietic progenitor cells to undergo respiratory epithelial differentiation ex vivo, and to engraft and attenuate alveolar disruption in injured newborn murine lungs in vivo.
  
  
  METHODS
  Respiratory epithelial differentiation was studied in CD34+ cells expanded in the presence of growth factors and cytokines ("basic" medium), in one group supplemented with dexamethasone ("DEX"). Expanded or freshly isolated CD34+ cells were inoculated intranasally in newborn mice with apoptosis-induced lung injury. Pulmonary engraftment, lung growth and alveolarization were studied at 8 weeks post-inoculation.
  
  
  RESULTS
  SP-C mRNA expression was seen in 2/7 CD34+ cell isolates expanded in basic media and in 6/7 isolates expanded in DEX, associated with cytoplasmic SP-C immunoreactivity and ultrastructural features suggestive of type II cell-like differentiation. Administration of expanding CD34+ cells was associated with increased lung growth and, in animals treated with DEX-exposed cells, enhanced alveolar septation. Freshly isolated CD34+ cells had no effect of lung growth or remodeling. Lungs of animals treated with expanded CD34+ cells contained intraalveolar aggregates of replicating alu-FISH-positive mononuclear cells, whereas epithelial engraftment was extremely rare.
  
  
  CONCLUSIONS
  Expanded cord blood CD34+ cells can induce lung growth and alveolarization in injured newborn lungs. These growth-promoting effects may be linked to paracrine or immunomodulatory effects of persistent cord blood-derived mononuclear cells, as expanded cells showed limited respiratory epithelial transdifferentiation.
authors.affiliation: Department of Pathology, Women and Infants Hospital, Providence, RI, USA.
authors.forename: Quanfu
authors.initials: Q
authors.lastname: Mao
authors.forename: Sharon
authors.initials: S
authors.lastname: Chu
authors.forename: Sailaja
authors.initials: S
authors.lastname: Ghanta
authors.forename: James F
authors.initials: JF
authors.lastname: Padbury
authors.forename: Monique E
authors.initials: ME
authors.lastname: De Paepe
mesh_terms: D000818:Animals; D000831:Animals, Newborn; D036101:Cord Blood Stem Cell Transplantation / Q000379:methods*; D018380:Hematopoietic Stem Cell Transplantation / Q000379:methods*; D008168:Lung / Q000254:growth & development* / Q000601:surgery*; D055370:Lung Injury / Q000503:physiopathology* / Q000601:surgery*; D051379:Mice; D008822:Mice, Transgenic; D011650:Pulmonary Alveoli / Q000254:growth & development*; D016896:Treatment Outcome