title: Biodegradable polymer coating promotes the epithelization of tissue-engineered airway prostheses.
abstract: OBJECTIVE
  We have developed a prosthesis that includes a collagen layer for tracheobronchial reconstruction and applied it in a canine model. In previous studies luminal epithelization remained partial or rather slow because of the early disintegration of the collagen layer. We have improved this type of prosthesis by coating the luminal surface with a biodegradable polymer, which serves to protect the collagen layer. The effect of the polymer coating on the epithelization of the luminal surface of the prosthesis was examined.
  
  
  METHODS
  The main frame consisted of a polypropylene mesh tube, measuring 15 mm in inner diameter and 30 mm in length, with reinforcing rings. Collagen extracted from porcine skin was conjugated to this frame. The luminal surface was coated with a polymer, poly (L-lactic-acid-co-epsilon-caprolactone). In 5 beagle dogs the left main bronchus was replaced with this prosthesis, periodic bronchoscopic observations were conducted, and microscopic evaluations were performed.
  
  
  RESULTS
  All dogs survived until they were killed, except for 1 animal in which pneumonia developed, and this animal died at 13 months after replacement. None of the dogs showed adverse complications caused by the prosthesis. Bronchoscopic observations revealed that the polymer remained on the luminal surface for 2 weeks. The luminal surface in 4 dogs was completely covered with ciliated columnar epithelium or nonciliated squamous epithelium, and 90% epithelization was achieved in 1 dog.
  
  
  CONCLUSIONS
  The biodegradable polymer coating protected the collagen layer and promoted better epithelization. This improved epithelization on the luminal surface could therefore potentially increase the success rates in airway replacement with artificial prostheses.
authors: Department of Bioartificial Organs, Institute for Frontier Medical Sciences, Kyoto University, Kyoto, Japan. tsato@kuhp.kyoto-u.ac.jp
authors: Toshihiko
authors: T
authors: Sato
authors: Masato
authors: M
authors: Araki
authors: Naoki
authors: N
authors: Nakajima
authors: Koichi
authors: K
authors: Omori
authors: Tatsuo
authors: T
authors: Nakamura
mesh_terms: D020341:Absorbable Implants; D000818:Animals; D001980:Bronchi / Q000601:surgery*; D004285:Dogs; D004848:Epithelium / Q000254:growth & development*; D011126:Polypropylenes; D011474:Prosthesis Design; D023822:Tissue Engineering; D014132:Trachea / Q000601:surgery*
chemical_list: D011126:Polypropylenes