Isolation of Dentin Matrix Proteins and the Effect on Human Pulp Cells

During tooth development odontoblasts embed growth factors in the dentin matrix, where their potential for biochemical signaling is preserved. They can be liberated later by demineralising agents and might influence immune response as well as the behavior of pulp cells. The aim of this study was to investigate the impact of dentin matrix proteins (DMPs) on the migration, viability and mineralisation of human dental pulp cells. At first, a complex procedure to isolate, purify and concentrate DMPs (up to 80,000 pg/ml TGF-β1) from human dentin was established. DMPs were utilised at different concentrations in a modified Boyden chamber assay to investigate chemotactic effects on pulp cells after 24 hours. Viability was analysed by MTT testing over a period of 14 days, and alizarin staining after 21 days provided information on the induction of mineralisation. DMPs showed a concentration-dependent chemotactic effect on human pulp cells and were able to influence their metabolic activity. Furthermore, they induced mineralisation that indicated cellular differentiation. These investigations show the potential of endogenous signaling molecules from human dentin to influence viability and enhance the migration as well as differentiation of pulp cells. The release of DMPs, which is easy to achieve in the clinic through the superficial demineralisation of dentin, might optimise procedures in vital pulp therapy as well as in regenerative endodontics in the near future. Keywords: dental pulp cells, dentin, EDTA, growth factors, regenerative endodontics