Effects of Basic Fibroblast Growth Factor on Proliferation, the Expression of Osteonectin (SPARC) and Alkaline Phosphatase, and Calcification in Cultures of Human Pulp Cells

Abstract

Basic fibroblast growth factor (bFGF) may be involved in the development and repair of dentine and pulp because bFGF, its related peptides, and FGF receptors are expressed in dental mesenchymal cells. In this study, we examined the effects of bFGF on DNA synthesis, osteonectin/SPARC levels, alkaline phosphatase (ALPase) activity, their mRNA levels, and calcium levels in cultures of human pulp cells. Pulp cells were isolated from three healthy upper wisdom teeth of three patients and maintained separately. These cells produced SPARC, ALPase, and calcified nodules and there was a close correlation between the SPARC-synthetic activity of the cell lines and their levels of ALPase and calcification. The levels of SPARC, ALPase and calcium deposits in the three pulp cell cultures were 10-250 times those of human foreskin fibroblasts. Western blots showed that the pulp cells produced 38-kDa SPARC. Northern blots showed that the pulp cells expressed flg (FGF receptor type 1) transcripts throughout all culture stages, irrespective of the presence or absence of bFGF. The addition of bFGF to the pulp cultures suppressed the increases in ALPase activity, SPARC synthesis, and their mRNA levels, although it increased the incorporation of [3H]thymidine into DNA> 10-fold. The effects of bFGF on ALPase activity and SPARC synthesis were reversible. Furthermore, bFGF abolished the calcification of the extracellular matrix; the calcium content of bFGF-free cultures. These findings suggest that bFGF is a potent mitogen for human pulp cells and that it inhibits the expression of the odontoblast phenotype by the cells at least partly at pretranslational levels.

Postnatal human dental pulp stem cells (DPSCs) in vitro and in vivo

“…Previous studies have looked at the odontogenic potential of adult human dental pulp by using a number of organ, explant, and cell-culture methods and noted the ability of such cultures to mineralize, at least in part (4,19,20,31). Our data also demonstrates the potential of DPSCs to form calcified deposits in vitro, as do BMSCs (5,6,32).…”

In vivo cellular repopulation of tubular elastin scaffolds mediated by basic fibroblast growth factor

“…Some studies, mostly with bone, have shown that bFGF decreases mineralization by inducing hypophosphatemia [44]. The addition of bFGF to dentin pulp cultures suppressed the increases in ALPase activity, SPARC synthesis, and their mRNA levels [45]. However, other studies have shown that bFGF is associated with osteogenic properties especially when used in combination with bone forming proteins such as BMPs [46,47].…”

Odontoblast Differentiation of Human Dental Pulp Cells in Explant Cultures

“…These systems were conducive for various stages of odontoblast differentiation, and either morphological or functional characteristics of differentiating odontoblasts were reported. The mineralization process was described, mainly after the formation of cell nodules [20,21,25,26]. However, cell polarization and the appearance of a cellular process, which are the main morphological features of odontoblast terminal differentiation, associated with expression of specific dentin proteins, were never convincingly reported in humans.…”