title: Tissue engineered cartilage "bioshell" protective layer for subcutaneous implants.
abstract: OBJECTIVE
  One current technique to reconstruct an ear for microtia involves the use of a high density polyethylene auricular implant; however, the implant can extrude if not covered in a temporoparietal fascia flap. Theoretically, an autologous tissue engineered cartilage "bioshell" protective coating around a permanent biocompatible implant might reduce potential extrusion to avoid the flap requirement. We hypothesized that if subjected to intentional exposure, a bioshell coating over an implant would provide enhanced wound healing.
  
  
  METHODS
  Six sheets of high density polyethylene and six sheets of 24 carat pure gold wire-mesh measuring 19 mm x 25 mm were implanted subcutaneously in an immunocompetent swine model. Half of each implant group were coated with chondrocytes (50-70 million cells/cm(3)) which were suspended in Pluronic F-127 30% hydrogel; the remaining implants without chondrocytes were used as controls. At 10 weeks post-implantation, partial implant exposure via excision of overlying skin was performed to simulate extrusion and the sites were allowed to heal secondarily.
  
  
  RESULTS
  All (6/6) of bioshell implants achieved wound closure after exposure by the seventh post-operative day; controls achieved closure at approximately 10 days. Bioshell neocartilage was evaluated and confirmed histologically using hematoxylin and eosin and safranin O stains. Histochemically, neocartilage approximated native cartilage with 60% glycosaminoglycans content.
  
  
  CONCLUSIONS
  A 'proof-of-principle' tissue engineered bioshell around subcutaneous high density polyethylene and gold implants generated an elastic neocartilage coating, elicited a low inflammatory reaction, and was associated with 30% faster wound healing.
authors.affiliation: The Pediatric Otolaryngology Service, Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, MA, USA.
authors.forename: Angelo
authors.initials: A
authors.lastname: Monroy
authors.forename: Koji
authors.initials: K
authors.lastname: Kojima
authors.forename: Marcielle A
authors.initials: MA
authors.lastname: Ghanem
authors.forename: Ana Cristina
authors.initials: AC
authors.lastname: Paz
authors.forename: Syed
authors.initials: S
authors.lastname: Kamil
authors.forename: Charles A
authors.initials: CA
authors.lastname: Vacanti
authors.forename: Roland D
authors.initials: RD
authors.lastname: Eavey
mesh_terms: D000818:Animals; D019902:Chondrocytes; D020099:Coated Materials, Biocompatible; D006046:Gold; D020442:Poloxamer; D011095:Polyethylenes; D019736:Prostheses and Implants; D019919:Prosthesis Implantation; D040521:Subcutaneous Tissue / Q000503:physiopathology* / Q000601:surgery; D013526:Surgical Mesh; D013552:Swine; D023822:Tissue Engineering; D014945:Wound Healing / Q000502:physiology*
chemical_list: D020099:Coated Materials, Biocompatible; C084562:Medpor; D011095:Polyethylenes; D020442:Poloxamer; D006046:Gold