title: Tracheal regeneration: evidence of bone marrow mesenchymal stem cell involvement.
abstract: OBJECTIVE
  Recent advances in airway transplantation have shown the ability of ex vivo or in vivo tracheal regeneration with bioengineered conduits or biological substitutes, respectively. Previously, we established a process of in vivo-guided tracheal regeneration using vascular allografts as a biological scaffold. We theorized that tracheal healing was the consequence of a mixed phenomenon associating tracheal contraction and regeneration. The aim of the present study was to determine the role that bone marrow stem cells play in that regenerative process.
  
  
  METHODS
  Three groups of 12 rabbits underwent a gender-mismatched aortic graft transplantation after tracheal resection. The first group received no cells (control group), the second group had previously received autologous green fluorescent protein-labeled mesenchymal stem cell transplantation, and the third group received 3 labeled mesenchymal stem cell injections on postoperative days 0, 10, and 21.
  
  
  RESULTS
  The clinical results were impaired by stent complications (obstruction or migration), but no anastomotic leakage, dehiscence, or stenosis was observed. The rabbits were killed, and the trachea was excised for analysis at 1 to 18 months after tracheal replacement. In all 3 groups, microscopic examination showed an integrated aortic graft lined by metaplastic epithelium. By 12 months, immature cartilage was detected among disorganized elastic fibers. Positive SRY gene detection served as evidence for engraftment of cells derived from the male recipient. EF-green fluorescent protein detection showed bone marrow-derived mesenchymal stem cell involvement.
  
  
  CONCLUSIONS
  The results of the present study imply a role for bone marrow stem cells in tracheal regeneration after aortic allografting. Studies are necessary to identify the local and systemic factors stimulating that regenerative process.
authors.affiliation: University of Paris Descartes, Alain Carpentier Foundation, EA Laboratory of Surgical Research, Assistance Publique-Hôpitaux de Paris, European Georges Pompidou Hospital, Paris, France. agathe.seguin@avc.aphp.fr
authors.forename: Agathe
authors.initials: A
authors.lastname: Seguin
authors.forename: Sonia
authors.initials: S
authors.lastname: Baccari
authors.forename: Muriel
authors.initials: M
authors.lastname: Holder-Espinasse
authors.forename: Patrick
authors.initials: P
authors.lastname: Bruneval
authors.forename: Alain
authors.initials: A
authors.lastname: Carpentier
authors.forename: Doris A
authors.initials: DA
authors.lastname: Taylor
authors.forename: Emmanuel
authors.initials: E
authors.lastname: Martinod
mesh_terms: D000818:Animals; D001011:Aorta / Q000637:transplantation*; D002478:Cells, Cultured; D005260:Female; D024282:Genes, sry; D049452:Green Fluorescent Proteins / Q000096:biosynthesis / Q000235:genetics; D017404:In Situ Hybridization, Fluorescence; D008297:Male; D045164:Mesenchymal Stem Cell Transplantation; D059630:Mesenchymal Stem Cells / Q000378:metabolism; D011474:Prosthesis Design; D019919:Prosthesis Implantation / Q000295:instrumentation*; D011817:Rabbits; D012038:Regeneration; D015607:Stents; D013997:Time Factors; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds; D014132:Trachea / Q000378:metabolism / Q000473:pathology / Q000503:physiopathology / Q000601:surgery*; D014162:Transfection
chemical_list: D049452:Green Fluorescent Proteins