title: Experimental repair of tracheal defect using a bioabsorbable copolymer.
abstract: BACKGROUND
  We investigated epithelialization and newly formed cartilage in an artificial trachea constructed using a bioabsorbable copolymer.
  
  
  METHODS
  Fifteen male Japanese white rabbits (2.5-2.8 kg) were divided into three groups. A full-thickness anterior defect (4 mm x 10 mm) was created in the trachea. The defect was implanted with one of the following bioabsorbable copolymers: caprolactone-lactide copolymer sponge sheet reinforced with poly(glycolic acid) fiber mesh (Cop) (n = 6, group A), Cop-incorporating gelatin hydrogel (n = 4, group B), and Cop-incorporating gelatin hydrogel with 100 microg of basic fibroblast growth factor (n = 5, group C). Each trachea was reinforced with an external nondegradable polymer stent. Three rabbits in each group were sacrificed at 1, 3, and 6 mo postoperatively and the trachea was evaluated histologically; other animals were sacrificed up to 12 mo postoperatively.
  
  
  RESULTS
  In groups A, B, and C there were two, one, and one postoperative deaths, respectively. In group A, epithelialization was recognized from 1 mo to 12 mo postoperatively, but no new cartilage was formed during the 12 mo following implantation. In group B, epithelialization was recognized 3 and 6 mo postoperatively, and new cartilage was detected at 6 mo after the operation. In group C, newly formed cartilage and epithelialization were observed 3, 6, and even 12 mo postoperatively. Furthermore, neovascularization was observed in groups B and C.
  
  
  CONCLUSIONS
  A bioabsorbable copolymer incorporating gelatin hydrogel induces tracheal epithelialization and formation of cartilage and vessels in tracheal defects, and could be available for clinical use in children.
authors.affiliation: Department of Pediatric Surgery, Graduate School of Comprehensive Human Sciences and University Hospital, University of Tsukuba, Tsukuba, Japan. tatekawa3966@s5.dion.ne.jp
authors.forename: Yukihiro
authors.initials: Y
authors.lastname: Tatekawa
authors.forename: Yoshito
authors.initials: Y
authors.lastname: Ikada
authors.forename: Hiroaki
authors.initials: H
authors.lastname: Komuro
authors.forename: Michio
authors.initials: M
authors.lastname: Kaneko
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D002356:Cartilage / Q000378:metabolism; D024043:Collagen Type II / Q000378:metabolism; D008297:Male; D011817:Rabbits; D012038:Regeneration; D014132:Trachea / Q000293:injuries / Q000473:pathology / Q000502:physiology / Q000601:surgery*; D014135:Tracheal Stenosis / Q000601:surgery; D014841:von Willebrand Factor / Q000378:metabolism
chemical_list: D024043:Collagen Type II; D014841:von Willebrand Factor