title: Study of hydroxyapatite osteoinductivity with an osteogenic differentiation of mesenchymal stem cells.
abstract: Osteoinductivity of hydroxyapatite (HA) was investigated using uncommitted pluripotent mouse stem cells, C3H10T1/2 in an in vitro differentiation assay. For comparative analysis, the cells were cultured on substrates made of osteoinductive HA, with biocompatible titanium and plastics as the negative control. HA exhibited the ability to induce expression of osteo-specific genes in C3H10T1/2, including alkaline phosphatase (ALP), type I collagen, and osteocalcin; compared with its insignificant up-regulation of the same genes in osteoblast-like cells, Saos-2. HA osteoinductivity exhibited in C3H10T1/2 was comparable to that of a bone morphogenetic protein (BMP) with reference to the up-regulation of osteo-specific genes except the core binding factor 1 (Cbfa1, Runx). This result implies a difference in osteogenic induction pathway initiated by HA and BMP. Using this mesenchymal stem cells (MSC) culture assay, osteoinductivity was also demonstrated to be present in the conditioned medium derived from MSC cultured on HA substrates. This conditioned medium exhibited excellent ability to up-regulate ALP in the absence of HA and BMP. The results suggest that the HA can interact with the cells and generate potent inductive substance released into the medium. Such substance in turn is able to induce uncommitted cells to differentiate into the osteolineage.
authors.affiliation: Program of Bioengineering; Hong Kong University of Science and Technology, Kowloon, Hong Kong, China.
authors.forename: Liwen
authors.initials: L
authors.lastname: Lin
authors.forename: King L
authors.initials: KL
authors.lastname: Chow
authors.forename: Yang
authors.initials: Y
authors.lastname: Leng
mesh_terms: D000469:Alkaline Phosphatase / Q000378:metabolism; D000818:Animals; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects*; D003470:Culture Media; D017886:Durapatite / Q000494:pharmacology*; D020869:Gene Expression Profiling; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D007477:Ions; D059630:Mesenchymal Stem Cells / Q000166:cytology* / Q000187:drug effects* / Q000201:enzymology; D051379:Mice; D009928:Organ Specificity / Q000187:drug effects; D010012:Osteogenesis / Q000187:drug effects*; D010710:Phosphates / Q000378:metabolism; D044967:Serum
chemical_list: D019485:Bone Morphogenetic Proteins; D003470:Culture Media; D007477:Ions; D010710:Phosphates; D017886:Durapatite; D000469:Alkaline Phosphatase; D002118:Calcium