JOURNAL OF TISSUE ENGINEERING AND REGENERATIVE MEDICINE RESEARCH ARTICLE J Tissue Eng Regen Med 2007; 1: 199–210. Published online in Wiley InterScience (www.interscience.wiley.com) DOI: 10.1002/term.26 Potential use of craniosynostotic osteoprogenitors and bioactive scaffolds for bone engineering L. Santos-Ruiz, 1 D. J. Mowatt, 1,2 A. Marguerie, 7 D. Tukiainen, 3 M. Kellom¨ aki, 3 P. T¨ orm¨ al¨ a, 3 E. Suokas, 4 H. Arstila, 5 N. Ashammakhi 3,6 and P. Ferretti 1 * 1 Developmental Biology Unit, UCL Institute of Child Health, London, UK 2 Craniofacial Unit, Great Ormond Street Hospital for Children, London, UK 3 Institute of Biomaterials, Tampere University of Technology, Tampere, Finland 4 Linvatec Biomaterials Ltd, Tampere, Finland 5 ˚ Abo Academi, Turku, Finland 6 Department of Surgery, Oulu University Hospital, Oulu, Finland 7 DanioLabs Ltd., Unit 7330, Cambridge Research Park, Cambridge, UK Abstract The cranial bone has a very limited regenerative capability. Patients with craniosynostosis (the premature fusion of cranial sutures, leading to skull abnormalities) often require extensive craniofacial reconstruction and repeated surgery. The possibility of grafting autologous osteoprogenitor cells seeded on bioabsorbable matrices is of great potential for inducing regeneration of craniofacial structure and protecting the brain from external insult. To this purpose we have studied the behaviour of normal and craniosynostotic mouse osteoblast cell lines, and of human primary osteoprogenitors from craniosynostotic patients. We have monitored their ability to grow and differentiate on plastic and on a scaffold composed of bioactive glass and bioabsorbable polymer by live fluorescent labelling and expression of bone differentiation markers. Cells from syndromic patients display a behaviour very similar to that observed in the stable mouse cell line we generated by introducing the human FGFR2-C278F, a mutation found in certain craniosynostosis, into MC3T3 osteblastic cells, indicating that the mutated cell line is a valuable model for studying the cellular response of human craniosynostotic osteoblasts. Both normal and mutated calvarial osteoprogenitors can attach to the bioactive scaffold, although mutated cells display adhesion defects when cultured on plastic. Furthermore, analysis of bone differentiation markers in human osteoblasts shows that the composite mesh, unlike PLGA 80 plates, supports bone differentiation. The ability of the mesh to support homing and differentiation in both normal and mutant osteoprogenitors is important, in view of further developing autologous biohybrids to repair cranial bone deficits also in craniosynostotic patients undergoing extensive reconstructive surgery. Copyright  2007 John Wiley & Sons, Ltd. Received 5 February 2007; Revised 30 March 2007; Accepted 2 April 2007 Keywords osteoblast; osteogenic; craniosynostosis; bioactive glass; bioabsorbable polymer; FGFR; mouse; human 1. Introduction A variety of single point mutations in fibroblast growth factor receptors (FGFRs) causes craniosynostoses (1/2500 live births), such as Apert, Crouzon and Pfeiffer syndromes, where premature closure of one or more *Correspondence to: P. Ferretti, Developmental Biology Unit, UCL Institute of Child Health, 30 Guilford Street, London WC1N 1EH, UK. E-mail: ferretti@ich.ucl.ac.uk cranial sutures results in severe craniofacial malforma- tions (Burke et al., 1998; Wilkie, 1997). These children often require extensive craniofacial reconstruction and repeated surgery (Panchal and Uttchin, 2003; Littlefield, 2004). In addition to bone fixation, extensive reconstruc- tive surgery can involve leaving critical size defects in the cranium that need to be filled in with bone. In very young patients this is achieved by growth of the cranial bone after surgery, but in patients aged over 2 years these gaps are not spontaneously filled in by bone growth. Copyright  2007 John Wiley & Sons, Ltd.