Longitudinal bone growth occurs within the epiphyseal growth plate, a highly organized biological structure located at the distal ends of the long bones, via endochondral bone formation. This developmentally regulated process is finely tuned through the interaction of circulating systemic hormones and locally produced peptide growth factors, the net result of which is to trigger changes in gene expression by growth plate chondrocytes. These molecular events lead to carefully orchestrated alterations in chondrocyte size, extracellular matrix components, secreted enzymes, growth factors and receptor expression. These events finally result in calcification of the matrix, chondrocyte death, vascular invasion and the completion of endochondral bone formation. Although the past several years have seen important progress in the identification of numerous important factors, which, in a complex and integrated network, control longitudinal bone growth, many of the signaling pathways and their interactions in the growth plate remain poorly understood. The ESPE Growth Plate Working Group (EUROGROP) was established in 2000 with the aim of bringing together both basic and clinical European research groups with an interest in the biology and pathology of the growth plate. The 7th EUROGROP Symposium was held as an official ESPE working group of the 46th ESPE Annual Meeting held in Helsinki, Finland, 2007. It enabled researchers, coming from all parts of the world to discuss their ongoing studies and exchange technical information. The program consisted of three lectures and four original papers, all followed by attractive discussions. This report summarizes the data presented and provides some comments on each of the presentations.
Abbreviations: 11beta-HSD: 11 Beta-Hydroxysteroid Dehydrogenase; Agc: Aggrecan; Aln: Alendronate; Asb- 4: Ankyrin Repeat and SOCS Box-Containing Protein 4; Atf6: Activating Transcription Factor6; BSP: Bisphosphonates; Calca: Calcitonin, Alpha Cdkn2a: Cyclin-Dependent Kinase Inhibitor 2A; Col1: Collagen 1; Col2: Collagen 2 Col10: Collagen 10; Dex: Dexamethasone; Elk1: Member of ETS Oncogene Family; Esr1: Estrogen Receptor 1 (Alpha); Fli1: Friend Leukemia Integration 1; Gabp: GA Repeat Binding Protein; GC: Glucocorticoids; Ghr: Growth Hormone Receptor; Hif-1alpha: Hypoxia-Inducible Factor 1 Alpha; hMSCs: Human Mesenchymal Stem Cells; Igf1: Insulin-Like Growth Factor 1; Igfbp1: Insulin-Like Growth Factor Binding Protein 1; Igf1r: Insulin-Like Growth Factor 1-Receptor; Igf2: Insulin-Like Growth Factor 2; Igf2r: Insulin-Like Growth Factor 2-Receptor; Nfe2l2: Nuclear Factor, Erythroid Derived 2, Like 2; Nrf1: Nuclear Respiratory Factor 1; Pam: Pamidronate; Prss11: HtrA Serine Peptidase 1; PTU: Propylthiouracil; Pycard: PYD and CARD Domain Containing; Rxrg: Retinoid X Receptor Gamma; Tam: Tamoxifen.