SYNOPSIS
In a previous in vivo transplantation study, we demonstrated hard tissue formation related with human dental pulp-derived (HDPD) cells in alginate scaffold. In the present in vitro study, we investigated the histology of the same HDPD cells with a collagen type I gel scaffold cultured in conditioned medium. Immunohistochemical, fine structure transmission electron microscopy (TEM), and molecular cell biological studies of HDPD cells-and-collagen mixture (cell clusters) demonstrated differentiation of odontoblast-like cells, which secreted dentin sialoprotein, dentin phosphoprotein and collagen types I and III in the extracellular matrix. The TEM study also revealed initial matrix vesicle-related and subsequent collagen-related mineralization. Results of this study elucidate that odontogenic HDPD cells have same properties as the odontoblast-like cells observed in our previous in vivo transplantation study. We concluded that HDPD cells differentiate and initiate dentin formation in the either collagen type I gel or alginate scaffolds, but they showed different morphology in in vivo and in vitro environments.

Key words: dental pulp-derived cell, human, collagen gel, scaffold, in vitro