Purpose The purpose of this study was to revise the clinical use of commercial BMP2 (Infuse) and BMP7 (Osigraft) based bone devices and explore the mechanism of action and efficacy of low BMP6 doses in a novel whole blood biocompatible device OSTEOGROW. Methods Complications from the clinical use of BMP2 and BMP7 have been systemically reviewed in light of their role in bone remodeling. BMP6 function has been assessed in Bmp6-/-mice by μCT and skeletal histology, and has also been examined in mesenchymal stem cells (MSC), hematopoietic stem cells (HSC) and osteoclasts. Safety and efficacy of OSTEOGROW have been assessed in rats and rabbits.Results Clinical use issues of BMP2 and BMP7 have been ascribed to the limited understanding of their role in bone remodeling at the time of device development for clinical trials. BMP2 and BMP7 in bone devices significantly promote bone resorption leading to osteolysis at the endosteal surfaces, while in parallel stimulating exuberant bone formation in surrounding tissues. Unbound BMP2 and BMP7 in bone devices precipitate on the bovine collagen and cause inflammation and swelling. OSTEOGROW required small amounts of BMP6, applied in a biocompatible blood coagulum carrier, for stimulating differentiation of MSCs and accelerated healing of critical size bone defects in animals, without bone resorption and inflammation. BMP6 decreased the number of Mladenka Jurin contributed equally to this paper. S. Vukicevic (*) : J. Curak : J. Brkljacic : M. Pauk : I. Erjavec : I. Dumic-Cule : R. Novak : V. Kufner : T. Bordukalo Niksic :

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Following bone fracture, a large number of growth factors, cytokines, and their cognate receptors involved in the repair process are active at the fracture site. To determine whether they appear in patients' blood as candidate biomarkers for following the outcome of healing, we analysed the plasma of 25 patients with an acute bone fracture following affinity plasma purification, SDS gel electrophoresis and liquid chromatography -tandem mass spectrometry (LC-MS/ MS). Two hundred and thirteen nonredundant proteins were identified in the in-gel analysis of pooled plasma proteins. Gene ontology (GO) analysis indicated that a majority of detected proteins were of extracellular origin, whereas only a small number were of intracellular (cytosol and nucleus) origin. A significant proportion of detected proteins was involved in the cell growth and proliferation, transport and coagulation. Twelve proteins were potentially related to bone and cartilage metabolism, and several have not been previously identified in the plasma, including: TGF-β induced protein IG-H 3 , cartilage acidic protein 1, procollagen C proteinase enhancer protein and TGF-β receptor III.Résumé Après une fracture, un grand nombre de facteurs de croissance, cytokines et leurs récepteurs apparentés interviennent dans le processus de réparation des foyers de fracture. Nous avons analysé ces différents facteurs circulants chez 25 patients ayant présenté une fracture après purification du sang, électrophorèses, chromatographie et spectrographie de masse. 213 protéines ont été identifiées. L'analyse génétique de la majorité de ces protéines montre qu'elles sont d'origine extra cellulaires avec un très petit nombre de protéines intra cellulaires provenant notamment du noyau. Une proportion significative des protéines détectées intervient au niveau de la croissance, de la prolifération cellulaire et des phénomènes de coagulation. 12 protéines sont spécifiquement en rapport avec les métabolismes osseux et cartilagineux, plusieurs d'entre-elles n'avaient pas été préala-blement identifiées au niveau du plasma comme la TGF-β, la protéine IG-H3, la CAP 1, le procollagène de type C, le TGF-β récepteur III.

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