title: Effect of coating Straumann Bone Ceramic with Emdogain on mesenchymal stromal cell hard tissue formation.
abstract: Periodontal tissue engineering requires a suitable biocompatible scaffold, cells with regenerative capacity, and instructional molecules. In this study, we investigated the capacity of Straumann Bone Ceramic coated with Straumann Emdogain, a clinical preparation of enamel matrix protein (EMP), to aid in hard tissue formation by post-natal mesenchymal stromal cells (MSCs) including bone marrow stromal cells (BMSCs) and periodontal ligament fibroblasts (PDLFs). MSCs were isolated and ex vivo-expanded from human bone marrow and periodontal ligament and, in culture, allowed to attach to Bone Ceramic in the presence or absence of Emdogain. Gene expression of bone-related proteins was investigated by real time RT-PCR for 72 h, and ectopic bone formation was assessed histologically in subcutaneous implants of Bone Ceramic containing MSCs with or without Emdogain in NOD/SCID mice. Alkaline phosphatase activity was also assessed in vitro, in the presence or absence of Emdogain. Collagen-I mRNA was up-regulated in both MSC populations over the 72-h time course with Emdogain. Expression of BMP-2 and the osteogenic transcription factor Cbfa-1 showed early stimulation in both MSC types after 24 h. In contrast, expression of BMP-4 was consistently down-regulated in both MSC types with Emdogain. Up-regulation of osteopontin and periostin mRNA was restricted to BMSCs, while higher levels of bone sialoprotein-II were observed in PDLFs with Emdogain. Furthermore, alkaline phosphatase activity levels were reduced in both BMSCs and PDLFs in the presence of Emdogain. Very little evidence was found for ectopic bone formation following subcutaneous implantation of MSCs with Emdogain-coated or -uncoated Bone Ceramic in NOD/SCID mice. The early up-regulation of several important bone-related genes suggests that Emdogain may have a significant stimulatory effect in the commitment of mesenchymal cells to osteogenic differentiation in vitro. While Emdogain inhibited AP activity and appeared not to induce ectopic bone formation, longer-term studies are required to determine whether it promotes the final stages of osteoblast formation and mineralization at gene and protein levels. While used in clinical applications, whether Emdogain and other commercial preparations of EMPs truly possess the capacity to induce the regeneration of bone or other components of the periodontium remains to be established.
authors.affiliation: Colgate Australian Clinical Dental Research Centre, Dental School, University of Adelaide, Frome Road Adelaide, South Australia 5005, Australia. krzysztof.mrozik@adelaide.edu.au
authors.forename: Krzysztof Marek
authors.initials: KM
authors.lastname: Mrozik
authors.forename: Stan
authors.initials: S
authors.lastname: Gronthos
authors.forename: Danijela
authors.initials: D
authors.lastname: Menicanin
authors.forename: Victor
authors.initials: V
authors.lastname: Marino
authors.forename: P Mark
authors.initials: PM
authors.lastname: Bartold
mesh_terms: D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000096:biosynthesis / Q000235:genetics; D001861:Bone Regeneration / Q000187:drug effects*; D018929:Cell Culture Techniques; D002454:Cell Differentiation; D002478:Cells, Cultured; D020099:Coated Materials, Biocompatible / Q000494:pharmacology; D050659:Core Binding Factor Alpha 1 Subunit / Q000096:biosynthesis / Q000235:genetics; D003746:Dental Enamel Proteins / Q000494:pharmacology*; D005347:Fibroblasts / Q000187:drug effects; D018507:Gene Expression Regulation, Developmental; D006801:Humans; D006882:Hydroxyapatites / Q000494:pharmacology; D059630:Mesenchymal Stem Cells / Q000187:drug effects*; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D010006:Osteoblasts / Q000378:metabolism; D010513:Periodontal Ligament / Q000166:cytology / Q000187:drug effects; D017154:Stromal Cells / Q000187:drug effects*; D050151:Subcutaneous Fat; D023822:Tissue Engineering
chemical_list: D055396:Bone Morphogenetic Protein 2; D020099:Coated Materials, Biocompatible; D050659:Core Binding Factor Alpha 1 Subunit; D003746:Dental Enamel Proteins; D006882:Hydroxyapatites; C109069:enamel matrix proteins; C094280:hydroxyapatite-tricalciumphosphate composite