Formation of a mandibular condyle in vitro by tissue engineering

Purpose: Mandibular reconstructive procedures often produce significant donor site morbidity. Recently, the use of minimally invasive techniques has been reported for mandibular reconstruction with decreased morbidity at the primary operative site. To date, these techniques have not addressed the graft donor site. We hypothesize that tissue-engineering techniques may be used to fabricate bone and thereby eliminate donor site morbidity. Methods: Porcine mesenchymal stem cells (pMSCs) were isolated from the bone marrow of 3 Yucatan minipigs and grown in standard culture flasks. When they became near-confluent, cells were detached and replated with the addition of osteogenic supplements. A model of a porcine mandibular condyle was made and used to fabricate porous polymer scaffolds from biodegradable Poly (DL)-lactic-co-glycolic acid (PLGA). Differentiated osteoblasts were transferred to the PLGA scaffold and cultured for 6 weeks in a rotational oxygen-permeable bioreactor system. The cultured constructs, consisting of scaffold and cells, were evaluated by gross, radiologic, and histologic examinations. Results: The engineered constructs were white and hard and had a shape that closely resembled that of the model condyle. Plain radiographs demonstrated that the radiodensity of the construct was between that of the normal condyle and that of control scaffolds. Histologically, bone was observed on the entire surface of the PLGA scaffolds with an average thickness of 0.03 mm. Bone was not observed in the control scaffolds. Conclusion: in this pilot study, autologous tissue-engineered bone constructs were successfully made by combining biodegradable polymers and pMSCs. (C) 2003 American Association of Oral and Maxillofacial Surgeons.