title: Silicate-substituted calcium phosphate with enhanced strut porosity stimulates osteogenic differentiation of human mesenchymal stem cells.
abstract: While many synthetic ceramic bone graft substitutes (BGSs) have osteoconductive properties (e.g. provide a physical scaffold for osteointegration of surrounding bone tissue), certain BGSs are osteostimulative in that they actively upregulate mesenchymal stem cell proliferation and stimulate differentiation into osteoblast-like cells. The osteostimulative properties of silicate-substituted calcium phosphate with enhanced porosity (SiCaP EP) were evaluated in vitro with STRO-1+ immunoselected human bone marrow derived mesenchymal stem cells (HBMSCs). Osteostimulative materials (SiCaP) and Bioglass 45S5 (Bioglass) were also assessed as positive controls along with non-silicate substituted hydroxyapatite as a negative control. HBMSCs were also assessed on Thermanox discs cultured in basal and osteogenic media to determine when osteogenic differentiation could be significantly detected with this in vitro cell system. HBMSC viability and necrosis, total DNA content, alkaline phosphatase (ALP) expression, and osteocalcin expression were evaluated after 7, 14, 21, and 28 days. It was demonstrated that SiCaP EP is osteostimulative based on its propensity to support STRO-1+ HBMSC proliferation and ability to promote the differentiation of HBMSCs down the osteoblastic lineage from ALP-expressing, matrix-producing osteoblasts to Osteocalcin-producing pre-osteocytes without the presence of external osteogenic factors. SiCaP EP permitted greater HBMSC attachment as well as ALP and Osteocalcin expression than Bioglass which may be attributed to its microstructure and chemistry.
authors.affiliation: Institute of Orthopaedics and Musculo-Skeletal Science, John Scales Centre for Biomedical Engineering, Institute of Orthopaedics and Musculo-Skeletal Science, University College London, Royal National Orthopaedic Hospital, Brockley Hill, Stanmore, Middlesex, HA7 4LP, UK.
authors.forename: Roberta Ferro
authors.initials: RF
authors.lastname: De Godoy
authors.forename: Stacy
authors.initials: S
authors.lastname: Hutchens
authors.forename: Charlie
authors.initials: C
authors.lastname: Campion
authors.forename: Gordon
authors.initials: G
authors.lastname: Blunn
mesh_terms: D000328:Adult; D000469:Alkaline Phosphatase / Q000737:chemistry; D001854:Bone Marrow Cells / Q000166:cytology; D002130:Calcium Phosphates / Q000737:chemistry*; D002454:Cell Differentiation; D049109:Cell Proliferation; D002470:Cell Survival; D002516:Ceramics / Q000737:chemistry; D004247:DNA / Q000737:chemistry; D017886:Durapatite / Q000737:chemistry; D005898:Glass / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D008297:Male; D059630:Mesenchymal Stem Cells / Q000166:cytology*; D008855:Microscopy, Electron, Scanning; D009336:Necrosis; D010006:Osteoblasts / Q000166:cytology; D015675:Osteocalcin / Q000737:chemistry; D010012:Osteogenesis / Q000502:physiology*; D016062:Porosity; D017640:Silicates / Q000737:chemistry*
chemical_list: D002130:Calcium Phosphates; D017640:Silicates; C425330:bioactive glass 45S5; D015675:Osteocalcin; D004247:DNA; D017886:Durapatite; D000469:Alkaline Phosphatase