Regeneration, Reconstruction & Restoration (Triple R)

Abstract

Introduction: Cell delivery in treatment of bone defects has been introduced to promote tissue healing in the recent years. However, no general consensus has been reached regarding the outcome of regenerative medicine for this purpose. The aim of this study was to review our 10 years of experience in application of mesenchymal stem cells (MSCs) in craniofacial bone defects. Applied Methodology: Iliac bone marrow, dental pulp and buccal fat pad were selected to harvest MSCs. Flow cytometric analysis, RT-PCR and differentiation staining including Alizarin red, Oil Red O and Toluidine blue were used to identify MSCs. Four groups of bone substitutes were used for cell delivery: synthetic scaffold [beta-tricalcium phosphate (B-TCP) and hydroxyapatite/tricalcium phosphate (HA/TCP)], xenograft [natural bovine bone mineral (NBBM)], allograft [freeze-dried bone (FDBA), demineralized freeze dried bone] and composite [polycaprolactone/TCP (PCL-TCP), demineralized freeze-dried bone/calcium sulfate]. Rat and rabbit calvaria, dog mandible, rabbit tibia sinus and alveolar cleft defects in human were used as the study models. Histomorphometric and radiomorphological analysis were used to determine new bone formation. Outcomes: Cell-treated groups showed greater new bone formation than cell-free group in all studies. Synthetic scaffolds showed better cell attachment according to scanning electron microscopy (SEM) results. In rat calvarial model, B-TCP loaded with MSCs showed better results than scaffolds carrying platelet rich plasma (PRP). NBBM showed less promising results both in dog mandible and ectopic bone formation in the masseter muscle. FDBA block fixed over a supracrestal defect in dog mandible showed 50% less new bone formation when compared with PCL-TCP as a carrier. Conclusion: More convergence studies with similar protocols of cell cultivation, culture, seeding and delivery should be done in the field of regenerative medicine for better generalizability of results for clinical setting.

Keywords: Mesenchymal stem cells; Bone regeneration; Tissue engineering; Craniofacial bone