Reconstruction of mandibular defects with autologous tissue-engineered bone.
OBJECTIVE
Maxillofacial reconstructive procedures often require bone graft harvesting, which results in donor site morbidity; the use of tissue-engineered bone would eliminate this problem. In this study, a novel scaffold design and new fabrication protocol were used to produce autologous tissue-engineered constructs (scaffolds seeded with cells) to reconstruct segmental mandibular defects in a minipig model.


METHODS
Porcine mesenchymal stem cells were isolated from the ilium. They were expanded in culture and seeded onto poly-dl-lactic-coglycolic acid scaffolds. The constructs were placed in a bioreactor and incubated for 10 days in medium and osteogenic supplements. Four full-thickness bony defects (2 x 2 cm) were created in the same pig's mandible. The constructs (n = 2) were placed into 2 of the defects as autologous grafts. One unseeded scaffold and 1 empty defect served as controls. At 6 weeks postimplantation, the pig was sacrificed, the mandible was harvested, and the grafted sites were evaluated by clinical, radiographic, and histologic methods.


RESULTS
The construct-implanted defects appeared to be filled with hard tissue resembling bone, whereas controls were filled with fibrous tissue. Radiographically, the tissue-engineered constructs were uniformly radiodense with bone distributed throughout. The interface between native bone and constructs was indistinct. Complete bone ingrowth was not observed in control defects. Osteoblasts, osteocytes, bone trabeculae, and blood vessels were identified throughout the defects implanted with constructs.


CONCLUSIONS
This "proof-of-principle" study indicates that porcine mandibular defects can be successfully reconstructed by in vitro cultured autologous porcine mesenchymal stem cells on a biodegradable polymer scaffold with penetration of bone and blood vessels.
Abukawa
Haru
H
Department of Oral and Maxillofacial Surgery, Massachusetts General Hospital, Boston 02114, USA.
Shin
Michael
M
Williams
W Bradford
WB
Vacanti
Joseph P
JP
Kaban
Leonard B
LB
Troulis
Maria J
MJ
D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry; D016025:Bone Transplantation / Q000000981:diagnostic imaging / Q000379:methods* / Q000473:pathology; D018929:Cell Culture Techniques; D006253:Haversian System / Q000473:pathology; D019344:Lactic Acid / Q000737:chemistry; D008334:Mandible / Q000000981:diagnostic imaging / Q000473:pathology; D008336:Mandibular Diseases / Q000000981:diagnostic imaging / Q000473:pathology / Q000601:surgery*; D008648:Mesoderm / Q000166:cytology; D010006:Osteoblasts / Q000473:pathology; D010011:Osteocytes / Q000473:pathology; D010012:Osteogenesis / Q000502:physiology; D011100:Polyglycolic Acid / Q000737:chemistry; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011108:Polymers / Q000737:chemistry; D011859:Radiography; D013234:Stem Cells / Q000166:cytology; D013552:Swine; D013556:Swine, Miniature; D023822:Tissue Engineering; D014182:Transplantation, Autologous
D001672:Biocompatible Materials; D011108:Polymers; D000077182:Polylactic Acid-Polyglycolic Acid Copolymer; D011100:Polyglycolic Acid; D019344:Lactic Acid