title: Accelerated angiogenesis by continuous medium flow with vascular endothelial growth factor inside tissue-engineered trachea.
abstract: OBJECTIVE
  To test the effects of a continuous medium flow inside DegraPol scaffolds on the reepithelialization and revascularization processes of a tissue-engineered trachea prosthesis.
  
  
  METHODS
  In this proof-of-principle study a continuous medium flow was maintained within a tubular DegraPol scaffold by an inserted porous catheter connected to a pump system. The impact of the intra-scaffold medium flow on the survival of a tracheal epithelial sheet wrapped around and on chondrocyte delivery to the DegraPol scaffold was studied. In the chick embryo, chorioallantoic membrane (CAM) model angiogenesis within the biomaterial was investigated.
  
  
  RESULTS
  Scanning electronic microscopy (SEM) images showed an intact epithelial layer after a 2-week support by continuous medium flow underneath. On histology, three-dimensional cell growth was detected in the continuous delivery group. The CAM assay showed that angiogenesis was enhanced within the DegraPol scaffolds when vascular endothelial growth factor/vascular permeability factor (VEGF/VPF) was added to the perfusate.
  
  
  CONCLUSIONS
  Taken together, these results demonstrated that the built-in perfusion system within DegraPol scaffolds was able to maintain an intact tracheal epithelial layer, allowed a continuous delivery of cells, and kept an efficient VEGF/VPF expression level which accelerated angiogenic response in the CAM assay. This design combines the in vitro and in vivo parts of tissue engineering and offers the possibility to be used as an in vivo bioreactor implanted for the tissue-engineered reconstruction of trachea and of other organs.
authors.affiliation: Division of Thoracic Surgery, University Hospital, CH-8091 Zurich, Switzerland. tqiang@hotmail.com
authors.forename: Qiang
authors.initials: Q
authors.lastname: Tan
authors.forename: Rudolf
authors.initials: R
authors.lastname: Steiner
authors.forename: Lin
authors.initials: L
authors.lastname: Yang
authors.forename: Manfred
authors.initials: M
authors.lastname: Welti
authors.forename: Peter
authors.initials: P
authors.lastname: Neuenschwander
authors.forename: Sven
authors.initials: S
authors.lastname: Hillinger
authors.forename: Walter
authors.initials: W
authors.lastname: Weder
mesh_terms: D000818:Animals; D001705:Bioprosthesis; D019149:Bioreactors; D002452:Cell Count; D002460:Cell Line; D019902:Chondrocytes / Q000502:physiology; D004847:Epithelial Cells / Q000502:physiology / Q000648:ultrastructure; D006801:Humans; D008855:Microscopy, Electron, Scanning / Q000379:methods; D008954:Models, Biological; D018919:Neovascularization, Physiologic / Q000502:physiology; D010865:Pilot Projects; D011091:Polyesters; D011140:Polyurethanes; D051381:Rats; D023822:Tissue Engineering / Q000379:methods*; D014132:Trachea / Q000098:blood supply* / Q000648:ultrastructure; D042461:Vascular Endothelial Growth Factor A / Q000008:administration & dosage*
chemical_list: C104154:DegraPol; D011091:Polyesters; D011140:Polyurethanes; D042461:Vascular Endothelial Growth Factor A