title: Development of a composite and vascularized tracheal scaffold in the omentum for in situ tissue engineering: a canine model.
abstract: OBJECTIVE
  We herein report on development of a composite (synthetic and biological) tracheal scaffold with vascularized autologous connective tissue in the omentum, followed by in situ tissue engineering of the composite scaffold with the pedicled omentum. In this preliminary report, we focus on development and evaluation of the vascularized autologous connective tissue in the omentum.
  
  
  METHODS
  In animal experiment 1, a polypropylene framework as a synthetic component was placed in the omental sac for 3 weeks and another was placed in the pouch of Douglas as a control in five beagle dogs. In animal experiment 2, a polypropylene framework placed in the omental sac for 3 weeks was compared with a polypropylene framework coated with porcine atelocollagen, which was also placed in the omental sac in another five dogs, to investigate whether the coating of porcine atelocollagen contributes to development of more vascularized connective tissue. Macroscopic, radiological and histological evaluations were performed for developed autologous connective tissue on the frameworks, with a focus on its thickness and capillary vessels.
  
  
  RESULTS
  In animal experiment 1, the polypropylene framework in the omentum developed a composite tracheal scaffold with homogeneous and significantly thicker (2.6 ± 0.5 vs 1.2 ± 0.4 mm, P <0.0001) connective tissue in which more capillary vessels per 10-power field of view (3.5 ± 2.2 vs 0 ± 0, P = 0.015) were identified, compared with the control in the pouch of Douglas. In animal experiment 2, the omentum developed significantly thicker connective tissue on the polypropylene framework coated with porcine atelocollagen (3.6 ± 0.7 vs 2.2 ± 0.4 mm, P <0.0001) in which not significantly more capillary vessels were identified (3.5 ± 2.2 vs 5.0 ± 2.7, P = 0.12), compared with the framework that was not coated.
  
  
  CONCLUSIONS
  Placement of the polypropylene framework in the omental sac resulted in development of homogeneous and vascularized autologous connective tissue on the polypropylene framework for a composite tracheal scaffold. The framework coated with porcine atelocollagen did not show an additional benefit in inducing vascularization. This preliminary report will be followed by the long-term evaluations of in situ tissue engineering of the composite tracheal scaffold.
authors.affiliation: Department of Bioartificial Organs, Institute for Frontier Medical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan Department of Thoracic Surgery, Kyoto University, Sakyo-ku, Kyoto, Japan mhamaji@kuhp.kyoto-u.ac.jp.
authors.forename: Masatsugu
authors.initials: M
authors.lastname: Hamaji
authors.affiliation: Department of Bioartificial Organs, Institute for Frontier Medical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan Department of Thoracic Surgery, Kyoto University, Sakyo-ku, Kyoto, Japan.
authors.forename: Fumitsugu
authors.initials: F
authors.lastname: Kojima
authors.affiliation: Department of Diagnostic Imaging and Nuclear Medicine, Kyoto University, Sakyo-ku, Kyoto, Japan.
authors.forename: Sho
authors.initials: S
authors.lastname: Koyasu
authors.affiliation: Center for Anatomical, Pathological and Forensic Medical Researches, Kyoto University, Sakyo-ku, Kyoto, Japan.
authors.forename: Tatsuaki
authors.initials: T
authors.lastname: Tsuruyama
authors.affiliation: Department of Bioartificial Organs, Institute for Frontier Medical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan Department of Thoracic Surgery, Kyoto University, Sakyo-ku, Kyoto, Japan.
authors.forename: Teruya
authors.initials: T
authors.lastname: Komatsu
authors.affiliation: Department of Cardiovascular Surgery, Kyoto University, Sakyo-ku, Kyoto, Japan.
authors.forename: Tsuyoshi
authors.initials: T
authors.lastname: Ikuno
authors.affiliation: Department of Thoracic Surgery, Kyoto University, Sakyo-ku, Kyoto, Japan.
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Date
authors.affiliation: Department of Bioartificial Organs, Institute for Frontier Medical Sciences, Kyoto University, Sakyo-ku, Kyoto, Japan.
authors.forename: Tatsuo
authors.initials: T
authors.lastname: Nakamura
mesh_terms: D000818:Animals; D049109:Cell Proliferation; D020099:Coated Materials, Biocompatible; D003094:Collagen / Q000008:administration & dosage; D004285:Dogs; D023421:Models, Animal; D018919:Neovascularization, Physiologic; D009852:Omentum / Q000098:blood supply* / Q000473:pathology / Q000601:surgery*; D011126:Polypropylenes; D011474:Prosthesis Design; D013997:Time Factors; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds; D014132:Trachea / Q000098:blood supply* / Q000473:pathology / Q000637:transplantation*; D014182:Transplantation, Autologous
chemical_list: D020099:Coated Materials, Biocompatible; D011126:Polypropylenes; C059821:atelocollagen; D003094:Collagen
keywords: Omentum; Prosthesis; Trachea