title: Tissue-engineered flexible ear-shaped cartilage.
abstract: BACKGROUND
  Previous attempts to engineer human ear-shaped constructs mimicked human shape but lacked the flexibility and size of a human ear. Recently, the authors engineered flexible cartilage by incorporating a perichondrium-like layer into the construct. In this study, they used lyophilized swine perichondrium as a pseudoperichondrium, examined its ability to confer flexibility to tissue-engineered cartilage, and used it to engineer flexible cartilage in the shape and size of a human ear.
  
  
  METHODS
  Auricular chondrocytes and perichondrium were isolated from swine. Chondrocytes were mixed with fibrin polymer and gelled to form 5 x 20-mm constructs. Constructs alone (control, n = 6) or constructs sandwiched between two layers of lyophilized swine perichondrium (experimental, n = 6) were implanted into athymic mice. Auricular chondrocytes in fibrin polymer and lyophilized perichondrium were also used to form a tri-layer, ear-shaped construct, which was implanted into an athymic rat and externally stented for 6 weeks (n = 1). At 12 weeks, constructs were analyzed with histology and gross mechanical testing.
  
  
  RESULTS
  New cartilaginous tissue was engineered in both the experimental and control groups. In samples laminated with lyophilized swine perichondrium, the intimate integration of the laminate with the neocartilage closely resembled the histoarchitecture of the native swine ear. Experimental constructs had mechanical properties similar to those of the native swine ear, while control constructs fractured with similar testing. The engineered ear could not be fractured with gross mechanical testing, and its size, shape, and flexibility remained stable.
  
  
  CONCLUSIONS
  This study demonstrates that it is possible to engineer a cartilage construct that resembles the human ear not only in shape but also in size and flexibility. This study also confirms that lamination is a reliable method to confer elastic-like flexibility to an engineered cartilage construct.
authors.affiliation: Division of Plastic Surgery, Massachusetts General Hospital, Harvard Medical School, Boston, Massachusetts 02130, USA.
authors.forename: Jian-Wei
authors.initials: JW
authors.lastname: Xu
authors.forename: T Shane
authors.initials: TS
authors.lastname: Johnson
authors.forename: Pejman M
authors.initials: PM
authors.lastname: Motarjem
authors.forename: Giuseppe M
authors.initials: GM
authors.lastname: Peretti
authors.forename: Mark A
authors.initials: MA
authors.lastname: Randolph
authors.forename: Michael J
authors.initials: MJ
authors.lastname: Yaremchuk
mesh_terms: D000818:Animals; D019902:Chondrocytes; D004425:Ear Cartilage; D004431:Ear, External; D015718:Fibrin Tissue Adhesive; D011108:Polymers; D051381:Rats; D015607:Stents; D013552:Swine; D023822:Tissue Engineering / Q000379:methods*
chemical_list: D015718:Fibrin Tissue Adhesive; D011108:Polymers