Use of cultivated osteoprogenitor cells to increase bone formation in segmental mandibular defects: an experimental pilot study in sheep.

The hypothesis of the present experimental pilot study was that autogeneous cultivated osteoprogenitor cells in porous calcium phosphate scaffolds can increase bone formation in segmental defects of the mandible. The autogenous osteoprogenitor cells of eight sheep were cultivated from bone biopsies from the iliac crest and seeded into cylindrical scaffolds of pyrolized bovine bone of an overall length of 35 mm and 13 mm in diameter. Segmental defects of 35 mm length were created unilaterally in the mandibles of the animals. Reconstruction was performed using cylinders with cultivated osteoprogenitor cells in four animals and empty scaffolds in the remaining four sheep, which served as controls. After 5 months, the mandibles were retrieved and the reconstructed areas were analyzed by qualitative and quantitative histology in serial undecalcified thick-section specimens. There was significantly more bone formation in the group that had received scaffolds with cultivated bone cells (P=0.028). Bone formation was present in 34.4% of the evaluated cross-sectional units in the seeded scaffolds, while it was found in 10.4% in the control group. Although the spatial distribution of bone formation was significantly different across the scaffold in both groups, osteoprogenitor cells appeared to have increased bone formation, particularly in the centre of the defect when compared to the control group. It is concluded that the repair of segmental defects of the mandible can be enhanced by the transplantation of autogenous osteoprogenitor cells in a porous calcium phosphate scaffold.