Repair of Palatal Bone Defects Using Osteogenically Differentiated Fat-Derived Stem Cells

Abstract

Although autogenous bone grafting remains the standard in the reconstruction of bone defects, disadvantages may include limited amount of bone and donor-site morbidity. Tissue engineering approaches can potentially obviate these problems. Fat contains a population of stem cells that can be isolated and differentiated into various cell lines, including osteocytes, adipocytes, and myocytes, depending on the culture conditions. In this study, the authors used osteogenically differentiated fat-derived stem cells to repair rat palatal bone defects. Fat-derived stem cells were isolated, differentiated into osteocytes in osteogenic medium, and seeded onto poly-L-lactic acid scaffolds. Rat palatal bone defects were surgically made and animals divided into four groups according to the type of implant for bone repair: group I, empty defect; group II, poly-L-lactic acid without cells; group III, poly-L-lactic acid with undifferentiated fat-derived stem cells; and group IV, poly-L-lactic acid with osteogenically differentiated fat-derived stem cells. Palates were harvested at 6 or 12 weeks after implantation (n = 8 per group at each time interval). Hematoxylin and eosin staining, immunohistochemical staining for osteocalcin, and histomorphometric measurements of new bone were performed. Defects in groups I, II, and III had no bone and were primarily filled with fibrous tissue. In contrast, there was substantial bone regeneration in group IV, which was statistically significant by histomorphometry compared with groups I, II, and III. Newly formed bone in group IV stained positive for osteocalcin. The authors successfully reconstructed palatal bone defects using absorbable three-dimensional scaffolds seeded with osteogenically differentiated fat-derived stem cells. This study demonstrates the feasibility of reconstructing bony defects with fat-derived stem cells.