Basic fibroblast growth factor enhances the growth and expression of the osteogenic phenotype of dexamethasone-treated human bone marrow-derived bone-like cells in culture

Basic fibroblast growth factor (bFGF) was shown to enhance rat stromal bone marrow cells in culture to produce mineralized bone-like tissue in response to dexamethasone (Des) treatment (Pitaru ct al,, J Bone Miner Res 8:919; 1993), The purpose of this study was to explore the effect of bFGF on Dex-treated human stromal bone marl om cells (hSBMC) in culture, Human SBMC from 6 patients were cultured for 14 days (P-0) and then subcultured and grown for 28 days in the presence of Des (10(-8) mol/L), The effect of bFGF on cell proliferation at P-0 and protein content, DNA content, alkaline phosphatase activity (ALP), osteocalcin secretion, and formation of mineralized bone-like tissue (MBT) at P-1 was analyzed. bFGF treatment resulted in a 2.4-fold increase in cell number at P-0 and a concentration-dependent increase in [H-3]-thymidine incorporation at P-1, reaching a maximum increase of 3.7-fold at a concentration of 0.3 ng/mL. Furthermore, bFGF significantly increased both DNA content (two- to threefold), protein content (five- to sixfold), and the amount of MBT (up to 20-fold) at P-1 cultures. Morphological evaluation of the MBT at the electron microscope level revealed a mineralization process along collagen fibrils similar to the natural process. The osteogenic nature of the bFGF-treated cultures was fur ther shown by their ALP activity, as well as osteocalcin secretion in response to 1,25-dihydroxyvitamin D-3, In conclusion, bFGF demonstrated a stimulatory effect on the proliferation of Dex-treated hSBMC-derived osteoprogenitors while maintaining their capacity to fully differentiate and form bone-like tissue in culture. (Bone 23: 111-117; 1998) (C) 1998 by Elsevier Science Inc. All rights reserved.