Addition of BMP-2 or BMP-6 to dexamethasone, ascorbic acid, and ß-glycerophosphate may not enhance osteogenic differentiation of human periodontal ligament cells.

This study was designed to investigate the potential merits of the combined use of bone morphogenetic protein (BMP)-2 or BMP-6 and osteogenic supplements (OS) [dexamethasone, ascorbic acid (AA), and ß-glycerophosphate] on osteogenic differentiation of periodontal ligament cells (PDLCs). Osteogenic differentiation was evaluated by quantitative alkaline phosphatase (ALP) assay, alizarin red staining, quantitative calcium assay, and the qRT-PCR analysis for the expression of collagen type I, runt-related transcription factor-2, osteopontin (OPN), and osteocalcin in PDLCs. Culture with BMP-2 or BMP-6+AA increased ALP activity of PDLCs, suggesting their osteo-inductive effects. However, longer duration of culture showed neither of the BMPs induced in vitro mineralization. In contrast, OS were able to increase ALP activity and OPN expressions, and also induced in vitro mineralization. The mineralization ability was not enhanced by the addition of BMP-2 or BMP-6. These findings suggest that the addition of BMP-2 or BMP-6 to OS may not enhance an osteogenic differentiation of hPDLCs.

Osteogenic differentiation of human dental pulp stem cells on ß-tricalcium phosphate/poly (l-lactic acid/caprolactone) three-dimensional scaffolds.

Functional tissue engineering for bone augmentation requires the appropriate combination of biomaterials, mesenchymal stem cells, and specific differentiation factors. Therefore, we investigated the morphology, attachment, viability, and proliferation of human dental pulp stem cells cultured in xeno-free conditions in human serum medium seeded on ß-tricalcium phosphate/poly(l-lactic acid/caprolactone) three-dimensional biomaterial scaffold. Additionally, osteogenic inducers dexamethasone and vitamin D(3) were compared to achieve osteogenic differentiation. Dental pulp stem cells cultured in human serum medium maintained their morphology; furthermore, cells attached, remained viable, and increased in cell number within the scaffold. Alkaline phosphatase staining showed the osteogenic potential of dental pulp stem cells under the influence of osteogenic medium containing vitamin D(3) or dexamethasone within the scaffolds. Maintenance of dental pulp stem cells for 14 days in osteogenic medium containing vitamin D(3) resulted in significant increase in osteogenic markers as shown at mRNA level in comparison to osteogenic medium containing dexamethasone. The results of this study show that osteogenic medium containing vitamin D(3) osteo-induced dental pulp stem cells cultured in human serum medium within ß-tricalcium phosphate/poly(l-lactic acid/caprolactone) three-dimensional biomaterial, which could be directly translated clinically.

Vitamin D(3) metabolites induce osteogenic differentiation in human dental pulp and human dental follicle cells.

Vitamin D(3) metabolites regulate the bone metabolism and 1α,25-dihydroxyvitamin D(3) (1α,25(OH)(2)D(3)) is known to play an important role in teeth mineralization. However, little is known about the potential of vitamin D as an osteogenic inducer in human dental pulp (hDPCs) and dental follicle cells (hDFCs) in vitro. Therefore, we investigated the effects of vitamin D(3) metabolites 1α,25(OH)(2)D(3) and 25-hydroxyvitamin D(3) (25OHD(3)) on proliferation and osteogenic differentiation of hDPCs and hDFCs in vitro. We also examined whether vitamin D(3) metabolic enzymes were regulated in hDFCs and hDPCs. Cell proliferation was decreased by both metabolites in hDPCs and hDFCs. Vitamin D(3) metabolites increased ALP activity and induced mineralization when osteogenic supplements (OS; l-ascorbic acid-2-phosphate+ß-glycerophosphate) were added, though the expression of osteocalcin (OC) and osteopontin (OPN) were regulated without the addition of OS. CYP24 and CYP27B1 expressions were upregulated by vitamin D(3) metabolites and 25OHD(3) was converted into 1α,25(OH)(2)D(3) in the culture medium. These results confirm that 1α,25(OH)(2)D(3) (10 and 100 nM) and 25OHD(3) (500 nM) can be used as osteogenic inducers synergistically with osteogenic supplements for differentiation of hDPCs and hDFCs. Furthermore, our findings strengthen our knowledge about the role of hDPCs and hDFCs as vitamin D(3) target cells.