P-15 (GTPGPQGIAGQRGVV), a fifteen residue synthetic peptide, is a structural analogue of the cell binding domain of Type 1 collagen and creates a biomimetic environment for bone repair when immobilized on anorganic bovine mineral (ABM) scaffolds. ABM-P-15 scaffolds have been shown to enhance bone marrow stromal cell growth and differentiation. This study aimed at evaluating the osteogenic potential of human dental pulp stromal cells (HDPSCs) compared to human bone marrow stromal cells (HBMSCs) in monolayer and on 3D ABM-P-15 scaffolds in vitro and in vivo. HDPSCs and HBMSCs were cultured as monolayers in basal or osteogenic media for 3 weeks. Osteogenic differentiation was confirmed using alkaline phosphatase (ALP) staining and ALP specific activity (ALPSA). In addition, the presence and distribution of osteogenic markers including Type 1 collagen, bone sialoprotein (BSP), osteopontin (OPN) and osteocalcin (OCN) was determined by immunohistochemisty. Gene expression for COL1, RUNX2 and OCN was determined using RT-PCR after 1, 3 and 5 weeks in basal culture. For 3D culture, HDPSCs were seeded on ABM scaffolds ± P-15 (CeraPedics LLC) and cultured in basal media for 6 weeks. Cell viability and growth were visualized by confocal and scanning electron microscopy. Osteogenic differentiation was confirmed by ALP staining and ALPSA. For in vivo studies, HDPSCs were injected and sealed in diffusion chambers containing ABM-P-15 or ABM alone which were then implanted intraperitoneally in nude mice for 8 weeks. The retrieved samples were then processed for histology.Introduction
Materials and Methods
