Histomorphometric Evaluation of Bone Regeneration Induced by Biodegradable Scaffolds as Carriers for Dental Pulp Stem Cells in a Rat Model of Calvarial "Critical Size" Defect

Abstract

Objective: The aim of this study was to test specific stem cells that could enhance bone formation in combination\ud with specific scaffolds.\ud Methods: Dental Pulp Stem Cells (DPSCs) were seeded with Granular Deproteinized Bovine Bone (GDPB) or Beta-Tricalcium Phosphate (ß-TCP) in a rat model of calvarial "critical size" defect. DPSCs were isolated from permanent human teeth, obtained and characterized using specific stem cells markers (Nanog and Oct-4) by real time-PCR and immunofluorescence. Cells were differentiated for 10-15 days towards the osteoblastic phenotype with 100μM L-ascorbic acid, added every day in culture medium and 20 vol. percentage of FBS in α-MEM medium. Osteogenic commitment was evaluated with real time-PCR by measuring the expression of specific markers (osteonectin and runx2). When a sufficient cell number was obtained, DPSCs were trypsinized, washed in culture medium and seeded onto the GDPB and ß-TCP scaffold sat a density of 0.5-1×106 cells/scaffold. Two bilateral critical-size circular defects (5 mm diameter; 1 mm thickness) were created from the parietal bone of the 8 athymic T-cell deficient nude rats. One cranial defect for each rat was filled with the scaffold alone and the other defect with the scaffold seeded with stem cells. After 12 weeks post-surgery animals were euthanized and histomorphometric analysis was performed. Differences between groups were analyzed by one-way analysis of variance (ANOVA) followed by Fisher's Protected Least Significant Difference (PLSD) post-hoc test. A p-value <0.05 was considered statistically significant.\ud Results: GDPB group presented higher percentage of lamellar bone than that of GDPB/DPSC, ß-TCP alone had lower levels as compared to ß-TCP/DPSC. The addition of stem cells significantly increased woven bone formation in both scaffold-based implants, although still higher in GDPB based implants.\ud Conclusion: Our findings indicate that GDPB and ß-TCP used as scaffold to induce bone regeneration may benefit from adding DPSC to tissue-engineered constructs

Bone Regeneration in Iliac Crestal Defects: An Experimental Study on Sheep

“…The improvement of successful methods for the induction of bone regeneration represents a continuous challenge in dentistry. Recently Annibali et al described that the use of biomaterials has been adopted to guide and favor bone regeneration due to their capability to mimic the natural environment of the extracellular matrix [ 9 ]. Scarano et al evidenced that a lack of horizontal and/or vertical bone in implant sites may cause major clinical problems and needs to be corrected prior to or at the moment of implant placement [ 10 ].…”

Bone Regeneration Induced by Bone Porcine Block with Bone Marrow Stromal Stem Cells in a Minipig Model of Mandibular “Critical Size” Defect

“…Yet others accumulate fat, identified by oil red O staining [ 22 ], while some colonies form cartilage as identified by alcian blue staining [ 23 ]. In a recent study [ 24 ] on mice mesenchymal stem cells derived from dental pulp and periosteum, a difference in bone regeneration was found, confirming the hypothesis of enhancing regeneration with mesenchymal stem cells. It was measured as a percentage of bone volume on the total defect area, when seeded with scaffold block deproteinized porcine bone (BDPB) alone and with dental pulp and periosteal stem cells.…”

Histological Evaluation of A unilateral Critical-Sized Mandibular Defect Reconstruction using human dental pulp stem cells by Light Microscope and Real-Time Quantitative PCR

“…Osteoblasts deposited additional woven bone (matrix) into the defect around 2 weeks after the initial implantation. Nonetheless, bone mineralization or remodeling began only once the shape of the new bone was adapted to the old tissue [38].…”