Cell Specification
Bone is a dynamic tissue, being continuously remodeled by the coordinated actions of osteoclasts and osteoblast lineage. Osteoblasts, the bone-forming cells, are derived originally from pluripotent mesenchymal stem cells. They synthesize and secrete an organic extracellular matrix, osteoid, which is composed primarily of 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. As the skeleton reaches maturity, the number and size of osteoblasts decrease; but dormant cells remain capable of responding to injury and producing new bone as in the healing of a fracture. In later life, the activity of osteoblasts is influenced directly by circulating levels of parathyroid hormone. Osteoblasts express protease-activated receptor-1 and vescular endothelial cell growth factor [1]. Studies show that Leukemia inhibitory factor can bind to the osteoblast cell surface and induce bone formation both in vitro and in vivo [2]. The balance between osteoblast recruitment, proliferation, differentiation and apoptosis in sutures between cranial bones is essential for calvarial bone formation [3].

HCO from ScienCell Research Laboratories are isolated from human calvariae. HCO are cryopreserved at primary cultures and delivered frozen. Each vial contains >5 x 10⁵ cells in 1 ml volume. HCO are characterized by the cytochemically detection of AP and mineral deposition. HCO are negative for HIV-1, HBV, HCV, mycoplasma, bacteria, yeast and fungi. HCO are guaranteed to further expand for 15 population doublings in the conditions provided by ScienCell Research Laboratories.

Recommended Medium
It is recommended to use Osteoblast Medium (ObM, Cat. No. 4601) for the culturing of HCO in vitro.

Product Use
HCO are for research use only. It is not approved for human or animal use, or for application in in vitro diagnostic procedures.

Storage
Directly and immediately transfer cells from dry ice to liquid nitrogen upon receiving and keep the cells in liquid nitrogen until cell culture needed for experiments.

Shipping
Dry ice.

Reference
[1] Steinbrech, D. S., Mehrara, B. J., Saadeh, P. B., Greenwald, J.A., Spector, J. A., Gittes, G. K. and Longaker, M. T. (2000) VEGF expression in an osteoblast-like cell line is regulated by a hypoxia response mechanism. Am. J. Physiol. Cell Physiol. 278: C853-C860.
[2] Dazai, S., Akita, S., Hirano, A., Rashid, M. A., Naito, S., Akino, K., Fujii, T. (2000) Leukemia inhibitory factor enhances bone formation in calvarial bone defect. J. Craniofac. Surg. 11(6):513-20.
[3] Marie, P. J., Debiais, F., Hay, E. (2004) Regulation of human cranial osteoblast phenotype by FGF-2, FGFR-2 and BMP-2 signaling. Histol. Histopathol.17(3):877-85.