Changes in matrix extracellular phosphoglycoprotein expression before and during in vitro osteogenic differentiation of human dental papilla mesenchymal cells.

The purpose ofthis study is to characterise the expression of matri.x extracellular phosphoglycoprotein (MEPE) in cultured mesenchymal cells isolated from buman dental papilla (PaMCs) of impacted third . molars eithet:.before .or.d.u.r-ing--differentiation of these cells into osteof odontobtMts"': •Ya::viCs, •-• like mesenchymal cells deriving from human dental pulp (DPMCs), resulted positive for a number of mesenchymal markers including CD146 and STR0-1. During the first week in culture they showed a faster proliferation rate than DPMCs, coupled to an earlier down-regulation of MEPE. Also when tbe cells were further cultured in •osteogenic medium (containing -glycerophosphate, ascorbic acid and dexamethasone) for 40 days, MEPE down-regulation coupled to an increased expression of osteogenic markers, sueh as osteocalcin and alkaline phosphatase,- occurred earlier in PaMCs than in DPMCs. Thus, our data, indicating that also in PaMCs MEPE expression is higher when cells proliferate, whereas it is downregulated as cells differentiated, are in favour of a role ofMEPE as an early regulator of odontogenic differentiation. We also confirm the superior proliferative potential of PaMCs in comparison with DPMCs, coupled to a more rapid induction of osteogenic differentiation. Therefore, tbese cells represent an optimal source to be conveniently used for dental tissue engineering and tooth regeneration.