Tissue engineered cartilage "bioshell" protective layer for subcutaneous implants.
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.
Monroy
Angelo
A
The Pediatric Otolaryngology Service, Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, Boston, MA, USA.
Kojima
Koji
K
Ghanem
Marcielle A
MA
Paz
Ana Cristina
AC
Kamil
Syed
S
Vacanti
Charles A
CA
Eavey
Roland D
RD
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*
D020099:Coated Materials, Biocompatible; C084562:Medpor; D011095:Polyethylenes; D020442:Poloxamer; D006046:Gold