Tissue engineering of a human sized and shaped auricle using a mold.
OBJECTIVE
The creation of a tissue-engineered auricle was initially successful in an immunocompromised nude mouse model. Subsequently, an immunocompetent porcine model successfully generated a helical construct. We wished to evaluate the novel technique of using a mold to create a complete, anatomically refined auricle in a large animal model.


METHODS
Mixtures of autogenous chondrocytes and biodegradable polymers were used inside a perforated, auricle shaped hollow gold mold. Three biodegradable polymers (calcium alginate, pluronic F-127, and polyglycolic acid) were used to retain the seeded chondrocytes inside the mold. These molds, along with a control, were implanted subcutaneously in the abdominal area of 10 animals (pigs and sheep). The constructs were removed after 8 to 20 weeks and were assessed by gross morphology and histology.


RESULTS
All the gold implants were well tolerated by the animals. The implants using calcium alginate (n = 3) generated constructs of the exact shape and size of a normal human ear; the histology demonstrated mostly normal cartilage with some persistent alginate. The implants with pluronic F-127 (n = 3) resulted in cartilage with essentially normal histology, although leakage outside the molds and external cartilage generation was noted. Polyglycolic acid implants (n = 3) produced no useful cartilage because of an inflammatory reaction with fibrosis. The empty control mold (n = 1) demonstrated only a very small amount of fibrous tissue inside.


CONCLUSIONS
A tissue-engineered human sized auricle of normal anatomic definition can be generated in an immunocompetent large-animal model using a mold technique. Although further refinements will be necessary, the technique appears promising for potential use in patients with microtia.
Kamil
S H
SH
Department of Otolaryngology, Massachusetts Eye and Ear Infirmary, and the Department of Otology and Laryngology, Harvard Medical School, Boston, 02114, USA.
Vacanti
M P
MP
Aminuddin
B S
BS
Jackson
M J
MJ
Vacanti
C A
CA
Eavey
R D
RD
D020341:Absorbable Implants; D002356:Cartilage / Q000502:physiology; D019902:Chondrocytes / Q000502:physiology; D004431:Ear, External / Q000033:anatomy & histology*; D006046:Gold / Q000627:therapeutic use*; D006801:Humans; D011108:Polymers; D019736:Prostheses and Implants; D023822:Tissue Engineering / Q000379:methods*
D011108:Polymers; D006046:Gold