title: Tracheal tissue-engineering: in-vivo biocompatibility of mechanically-stripped allogenic rabbit trachea with autologous epithelial covering.
abstract: BACKGROUND
  Successful trachea transplantation comprises the use of biocompatible constructs with little immune-reactivity, submucosal revascularization and creation of an epithelial covering. Allogenic chondrocytes might be protected from an overt immune-response due to physical isolation. Our aim was to evaluate in-vivo biocompatibility of allotracheae, stripped of their highly-immunogenic inner lining. Secondly, we established whether these constructs might serve as suitable scaffolds for autologous epithelial grafting.
  
  
  METHODS
  Mucosa and submucosa of 12 rabbit donor tracheae were mechanically peeled off. Cartilage was covered with Integra™ regeneration-template. Constructs were implanted within the recipient's lateral thoracic artery flap. Integra of 6 revascularized allotracheae was grafted with autologous buccal mucosa. Macroscopical, histological analysis and immunohistochemistry were performed.
  
  
  RESULTS
  Revascularization and buccal grafting was incomplete in the first 2 circular constructs. To enhance blood-vessel outgrowth, the following 10 transplants were opened longitudinally before implantation. Integra revascularized well. Grafted tracheae showed satisfactory mucosa-adherence, albeit with invasion of migrating epithelium within the Integra-scaffold.
  
  
  CONCLUSIONS
  Mechanically-stripped allotracheae exhibited beneficial biocompatibility up to two months. This approach might open doors in the treatment of long-segment tracheal pathologies of which immunosuppression is contra-indicated. Thickness of this layered construct limited practical feasibility of orthotopic transfer, though with further refinements, a clinically-useful transplant could be created.
authors.affiliation: a Department of Plastic & Reconstructive Surgery , University Hospitals Leuven , Leuven , Belgium.
authors.forename: Margot
authors.initials: M
authors.lastname: Den Hondt
authors.affiliation: b Lung Transplant Unit, Laboratory of Pulmonology, Department of Clinical and Experimental Medicine , KU Leuven - University of Leuven , Leuven , Belgium.
authors.forename: Bart M
authors.initials: BM
authors.lastname: Vanaudenaerde
authors.affiliation: c Department of Pathology , University Hospitals Leuven , Leuven , Belgium.
authors.forename: Erik K
authors.initials: EK
authors.lastname: Verbeken
authors.affiliation: a Department of Plastic & Reconstructive Surgery , University Hospitals Leuven , Leuven , Belgium.
authors.forename: Jan J
authors.initials: JJ
authors.lastname: Vranckx
keywords: Transplantation; acellular dermis; neovascularization; tissue scaffolds; trachea