To investigate the role of the IGF axis in the osteogenic differentiation of human dental pulp stromal/stem cells (HDPSCs) derived from healthy and carious teeth. Our translational aim is to investigate the potential use of IGF axis members for future therapeutic application in bone/dentine regeneration.
Method:
Freshly extracted healthy and carious third molars were collected from adult patients (20-40 years). Pulp cells were isolated, and expanded until passage 4 then cultured in either basal medium (α-MEM, plus 20% FBS, 1% Penicillin Streptomycin and 1% L-Glutamine) or osteogenic conditions (basal medium + 10 nM dexamethasone and 50 μg/ml L-ascorbic acid) for 1 and 3 weeks. Osteoblastic differentiation was investigated in both cultures using alkaline phosphatase (ALP) and Alizarin red staining. Q RT-PCR was used to confirm the expression of bone markers (ALP, osteonectin (OSN), osteopontin(OSP), and to investigate the changes in gene expression of the IGF axis (10 genes).
Result:
All gene expressions were investigated under osteogenic conditions and were normalized to expression levels under basal conditions.Healthy and carious HDPSCs were able to differentiate into osteoblasts. Carious HDPSCs showed higher proliferation capacity, and osteogenic differentiation ability. The gene expression of specific IGF axis members was altered under osteogenic conditions in both healthy and carious HDPSCs, compared to basal cultures. IGF-2 and IGFBP-2 showed up-regulation in both healthy and carious HDPSCs at 1 and 3 weeks. In healthy and carious HDSPCs, IGFBP-3 was down-regulated at both 1 and 3 weeks, whereas IGFBP-4 was down-regulated at week1 but up-regulated at week 3.
Conclusion:
The IGF axis plays an important role in osteogenic/ odontogenic differentiation of HDPSCs; cells derived from carious teeth had greater potential to differentiate toward the osteogenic / odontogenic lineage compared to those derived from healthy teeth. These findings can have a future impact on clinical approaches in restorative dentistry.