Introduction: Autogenous bone grafts remain the standard in the reconstruction of bony defects but they have disadvantages, including limited amounts of bone and donor site morbidity. Creating autologous bone grafts from osteogenically differentiated fat-derived stem cells could potentially solve these problems. As a proof of concept, we utilized bone grafts engineered from osteogenically differentiated fat-derived stem cells to reconstruct the alveolar palate defect in a rat cleft palate model.

Materials and Methods: Bone grafts were created by isolating rat fat-derived stem cells (FDSC) and differentiating them into osteocytes via exposure to media containing specific differentiating factors. Differentiated cells were seeded onto three-dimensional poly-lactic acid (PLLA) scaffolds to construct the grafts. Using a rat model, an 8 x 5 x 2 mm palatal defect was created surgically. Rats were divided into 4 groups according to the type of graft implanted: Group I- empty defect, Group II- PLLA without engineered cells, Group III- PLLA with FDSCs, Group IV- PLLA with osteogenically differentiated FDSCs. Animals were sacrificed at 6 and 12 weeks after surgery. Histological studies including immunohistochemical staining for osteocalcin and quantitative bone histomorphometry were performed.

Results: By H&E, there was no bone formation in Groups I, II, and III. However, there was a statistically significant increase in bone regeneration in Group IV with almost complete palatal regeneration. Osteocalcin staining was positive in the newly formed bone in Group IV.

Conclusions: The results of this study demonstrate that we can reconstruct surgically created bony defects in a rat model using absorbable grafts containing osteogenically differentiated fat-derived stem cells.