Bone morphogenetic protein 2 accelerates osteointegration and remodelling of solvent-dehydrated bone substitutes.
BACKGROUND
lt was the purpose of this study to investigate how bone morphogenetic protein 2 (BMP-2) influences remodelling and the biomechanics of solvent-dehydrated bone in the long run. Furthermore, the early influence of this growth factor on the substitute was investigated.


METHODS
Using a weight-bearing animal model, solvent-dehydrated bone was implanted in the tibial head of merino sheep ( n=12) after being loaded with BMP-2 (100 microg/100 microl). At 4 weeks ( n=6) and 9 months ( n=6) after surgery, histomorphological, histomorphometrical and biomechanical investigations were performed.


RESULTS
At 9 months after implantation of BMP-2-loaded specimens, the bone per tissue volume was high, with levels above those of physiological cancellous bone. The amount of remaining solvent-dehydrated bone was markedly decreased, and in contrast, the amount of newly formed bone was extremely high. The specimen degradation had already occurred within the first 4 weeks after implantation, showing no further impact throughout the 9-month period. Biomechanical investigations at 9 months after implantation demonstrated a yield strength which achieved levels at least equivalent to physiological cancellous bone. BMP-2 showed no significant impact on the biomechanical properties after 4 weeks, compared to specimens prior to implantation.


CONCLUSIONS
BMP-2 predominantly has an impact on the early implant degradation as well as bone formation, which leads to an almost completed bone remodelling of the solvent-dehydrated specimen within the study period of 9 months.
Kessler
S
S
Orthopedic Department, Städt. Krankenhaus Sindelfingen, Arthrur-Gruber-Str. 70, 71065 Sindelfingen, Germany. s.kessler@kh-sindelfingen.de
Koepp
H E
HE
Mayr-Wohlfart
U
U
Ignatius
A
A
Claes
L
L
Puhl
W
W
Günther
K P
KP
D000818:Animals; D001696:Biomechanical Phenomena; D001707:Biopsy, Needle; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000494:pharmacology*; D016723:Bone Remodeling / Q000187:drug effects*; D018786:Bone Substitutes; D016025:Bone Transplantation / Q000473:pathology*; D003890:Desiccation / Q000379:methods; D004195:Disease Models, Animal; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D016348:Osseointegration / Q000187:drug effects*; D012680:Sensitivity and Specificity; D012756:Sheep; D012997:Solvents; D016212:Transforming Growth Factor beta; D016474:Weight-Bearing / Q000502:physiology
C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D018786:Bone Substitutes; D012997:Solvents; D016212:Transforming Growth Factor beta