CHEMOTAXIS OF HUMAN OSTEOBLASTS - EFFECTS OF OSTEOTROPIC GROWTH-FACTORS

The in vitro chemotactic response of human osteoblasts was investigate d towards the following growth factors: TGF-beta, PDGFs, FGFs and IGFs . Human osteoblasts grown from trabecular bone after enzymatic digesti on were studied. TGF-beta stimulated the migration of human osteoblast s in a dose-dependent manner with a four-fold increase in migrated cel ls at 100 pg/ml, which was the optimum concentration. PDGF-BB also sti mulated migration four-fold in a dose-dependent manner with a maximum response at 10 ng/ml. PDGF-AA, IGF-I and IGF-II stimulated migration t wo-fold at 100 ng/ml. The results show that TGF-beta and PDGF-BB are i mportant regulators of human osteoblast migration, but other growth fa ctors IGF-I, IGF-II and PDGF-AA may also stimulate osteoblast migratio n. Our results additionally suggest that TGF-beta and PDGF-BB may part icipate in the recruitment of osteoblasts during bone remodeling since both TGF-beta and PDGF-BB are found in bone matrix and could be relea sed during osteoclastic bone resorption. They furthermore support a po ssible use of TGF-beta and PDGF-BB in growth factor-induced osteogenes is.