Gene array of PDL cells exposed to Osteogain in combination with a bone grafting material.

Abstract

The aim of the present study was to investigate the effects of Osteogain, a new formulation of enamel matrix derivative (EMD) in combination with a grafting material on a wide variety of genes for cytokines, transcription factors and extracellular matrix proteins involved in osteoblast differentiation. Primary human periodontal ligament (PDL) cells were seeded on natural bone mineral (NBM) particles coated with Osteogain for 24h and analyzed for regulated gene expression using a human osteogenesis gene super-array kit. Osteoblast-related genes include those transcribed during bone mineralization, ossification, bone metabolism, cell growth and differentiation as well as gene products representing extracellular matrix molecules, transcription factors and cell adhesion molecules. Osteogain significantly upregulated the expression of over 20 of the 100 genes examined including bone morphogenetic protein 2 (BMP2), TGFβ1, fibroblast growth factor (FGF), epidermal growth factor (EGF) and platelet-derived growth factor (PDGF) as well as some of their associated receptors. Osteogain also promoted gene expression of a number of osteoblast differentiation markers including collagen1α2 and alkaline phosphatase as well as cell adhesion molecules including fibronectin and a variety of integrin binding proteins. Interestingly, Osteogain promoted calcitonin receptor 55-fold and also promoted annexin A5 gene expression over 12-fold. The present study demonstrates that Osteogain is capable of either upregulating or downregulating the expression of a wide variety of genes including those for growth factors and cytokines when combined with a bone grafting material. The results from the present study demonstrate the large and potent effect of addition of Osteogain in combination to a bone grafting material over a wide variety of genes supporting osteogenesis.