Effectiveness of Dental Pulp-derived Stem Cells and Bone Marrowderived Mesenchymal Stromal Cells Implanted into a...

While bone marrow-derived mesenchymal stromal cells (BM-MSCs) have been used for many years in bone tissue engineering applications, the procedure still has drawbacks such as painful collection methods and damage to the donor site. Dental pulp-derived stem cells (DPSCs) are readily accessible, occur in high amounts, and show a high proliferation and differentiation capability. Therefore, DPSCs may be a promising alternative for BM-MSCs to repair bone defects.

The aim of this study was to investigate the bone regenerative potential of DPSCs in comparison to BM-MSCs in vitro and in vivo.

In vitro investigations included analysis of cell doubling time as well as proliferation and osteogenic differentiation. For the in vivo study, 36 male NMRI nude mice were randomized into 3 groups: 1) control (cell-free mineralized collagen matrix (MCM) scaffold), 2) MCM + DPSCs, and 3) MCM + BMMSCs. Critical size 2 mm bone defects were created at the right femur of each mouse and stabilized by an external fixator. After 6 weeks, animals were euthanized, and microcomputed tomography scans (μCT) and histological analyses were performed.

In vitro DPSCs showed a 2-fold lower population doubling time and a 9-fold higher increase in proliferation when seeded onto MCM scaffolds as compared to BM-MSCs, but DPSCs showed a significantly lower osteogenic capability than BM-MSCs. In vivo, the healing of the critical bone defect in NMRI nude mice was comparable among all groups.

Pre-seeding of MCM scaffolds with DPSCs and BM-MSCs did not enhance bone defect healing.