Native bovine bone morphogenetic protein improves the potential of biocoral to heal segmental canine ulnar defects

Abstract

We studied the effect of a composite implant consisting of coral and native bovine bone morphogenetic protein (BMP) on the healing of 2 cm segmental defects in the canine ulna. Plain coral and cortical autograft bone implants were used as controls. The fixation was temporary for 9 weeks with an intramedullary Kirschner wire (6 ulnas with a composite implant of coral and BMP, 6 with plain coral and 6 with an autograft) or a plate and screws (3 ulnas with a composite implant and 3 with plain coral). X-rays were taken at 3, 6, 9, 12, 16, 26 and 36 weeks, and mechanical torsion tests were performed at the end of the study. The score for bone formation and bone union evaluated from radiographs was significantly higher in the composite implant group than in the plain coral group at 16 weeks, but the score was even higher with autografts. BMP accelerated the resorption of the coral implant. The mechanical strength of the composite implants was higher than that of the bones with a plain coral implant (P<0.05), while the mechanical strength of the coral implants, even with BMP, was significantly lower than the strength of autografts (P<0.01). In conclusion, BMP enhanced the capacity of a coral implant to heal a segmental ulnar defect by increasing bone formation, but the effect of this combination was not as good as that of a cortico-cancellous autograft.Résumé Nous avons étudié l'effet d'un implant composite, fait de corail imprégné de protéine de la morphogenèse osseuse (BMP) bovine, sur la consolidation d'une perte de substance de 2 cm de l'os ulnaire canin. Des implants comprennent du corail simple ou des autogreffes d'os cortical étaient employées comme contrôles. Une fixation temporaire intramedullaire de 9 semaines était réalisée, soit avec des broches de Kirschner (6 os ulnaires avec un implant composite, 6 avec du corail simple, et 6 avec une autogreffe), soit avec une plaque-à-vis (3 avec un implant composite et 3 avec du corail simple). Des radiographies étaient prises 3, 6, 9, 12, 16, 26 et 36 semaines aprés la mise en place des implants, et des tests mécaniques de torsion étaient réalisées en fin d'étude. Aprés 16 semaines, les taux de formation et d'union osseuses étaient significativement plus élevés avec les implants composites qu'avec les implants de corail simple, mais des taux encore plus élevés étaient observés dans les essais avec les autogreffes. La BMP a accéleré la résorption de l'implant de corail. La résistance méca-nique des os avec un implant composite était plus forte que celle des os ayant un implant de corail simple (P<0.05), alors que la résistance mécanique des os traités par une autogreffe était plus forte (P<0.01) que celle des os ayant un implant de corail, avec ou sans BMP. En conclusion, la BMP améliore le pouvoir de consolidation des implants de corail qui reste cependant inférieur à celui observé avec les autogreffes.

Reindeer BMP extract in the healing of critical-size bone defects in the radius of the rabbit

“…BMPs combined with different carrier materials have been shown to heal experimental bone defects in many studies (Moore et al 1990, Viljanen et al 1996, Hollinger et al 1998, Sciadini and Johnson 2000, Tuominen et al 2000, Yudell and Block 2000, Chen et al 2002, Kokubo et al 2003, Barboza et al 2004. Until now, there have been no studies investigating the ability of reindeer BMP extract to heal long bone defects.…”

Bovine bone implant with bovine bone morphogenetic protein in healing a canine ulnar defect

“…We have previously found that BMP enhances the capacity of a coral implant to heal a segmental ulnar defect by increasing bone formation [16]. Therefore, it is possible that adjunction of BMP to a xenograft might improve its usability as a bone substitute.…”

“…The aim of this study was to test in the canine ulnar defect model, which is considered suitable for bone substitute and transplantation studies [4,8,12,15,16], whether BMP addition enhances the suitability of demineralized xenogeneic bovine bone for bone grafting and whether xenogeneic bone is a suitable carrier for BMPs.…”

Aplicabilidade de rhBMP-2 em diferentes técnicas de enxertia

“…As proteínas que foram isoladas (ou purificadas) até então são: BMP-1; BMP-2; BMP-3 (Osteogenina); BMP-4; BMP-5; BMP-6, BMP-7 e BMP-8; cada uma dessas proteínas tem uma capacidade osteoindutora diferente 38 . As BMPS recombinantes 2, 4 e 7 induzem formação óssea, sendo as mais testadas clinicamente 39 . O rhBMP-2, por exemplo, tem a maior capacidade osteoindutora dentre todas as BMPs 40 , participando da diferenciação de células mesenquimais em células com fenótipo de osteoblastos, aumentando a atividade da fosfatase alcalina, do Camp (em resposta ao hormônio da paratireoide) e de osteocalcina 41,42 .…”