Human Osteoblasts

Bone is a dynamic tissue, whose remodeling occurs continuously through the coordinated actions of both, osteoclasts and osteoblasts. Osteoblasts, the bone-forming cells, come from originally from pluripotent mesenchymal stem cells. They synthesize and secrete organic extracellular matrix, osteoid, whose main component is type I collagen. Osteoid is calcified by osteoblasts and during this process the cells become encased in lacunae within the calcified material and become osteocytes. Human Osteoblasts express protease-activated receptor-1 and vascular endothelial cell growth factor. Leukemia inhibitory factor can bind to the osteoblast cell surface and induce bone formation both in vitro and in vivo. The balance between osteoblast recruitment, proliferation, differentiation and apoptosis in sutures between cranial bones is essential for calvarial bone formation.