Endocultivation: the influence of delayed vs. simultaneous application of BMP-2 onto individually formed hydroxyapatite matrices for heterotopic bone induction.
When bone morphogenetic protein (BMP) is delivered to matrices in vivo may affect tissue engineered bone constructs for jaw reconstruction after cancer surgery. This study compared the effects of BMP application at different times after matrix implantation for heterotopic bone induction in a rat model. Hydroxyapatite blocks were implanted unilaterally onto the surface of the latissimus dorsi muscle. A second block was implanted onto the contralateral muscle after 1, 2 or 4 weeks and 200 μg rhBMP-2 was injected into the blocks on both sides. Bone formation and density inside the blocks was analysed by CT and histology. 8 weeks after BMP application increases in bone density within the scaffolds were most pronounced in the simultaneous application group (179 HU). Less pronounced increases were observed for the 1 (65 HU), 2 (58 HU) and 4 (31 HU; p<0.0001) week delay group. Homogeneous bone induction started from the central channel of the blocks. Capillaries and larger vessels were seen in all constructs, samples receiving delayed BMP treatment demonstrated significantly greater neovascularization. Delayed application of BMP was less effective for heterotopic bone formation than simultaneous application. A central channel allows homogeneous bone induction directly from the centre of the blocks.
Department of Oral and Maxillofacial Surgery, Christian-Albrechts-University Kiel, Arnold-Heller-Str. 16, 24105 Kiel, Germany. Mail@st-becker.de
S T
ST
Becker
H
H
Bolte
K
K
Schünemann
H
H
Seitz
J J
JJ
Bara
B E
BE
Beck-Broichsitter
P A J
PA
Russo
J
J
Wiltfang
P H
PH
Warnke
D020341:Absorbable Implants; D000818:Animals; D001857:Bone Matrix; D055396:Bone Morphogenetic Protein 2 / Q000008:administration & dosage*; D018786:Bone Substitutes / Q000008:administration & dosage*; D004334:Drug Administration Schedule; D016503:Drug Delivery Systems; D005260:Female; D006882:Hydroxyapatites / Q000008:administration & dosage*; D020007:Implants, Experimental; D016348:Osseointegration / Q000187:drug effects; D010012:Osteogenesis / Q000187:drug effects*; D051381:Rats; D011917:Rats, Inbred Lew; D013997:Time Factors; D023822:Tissue Engineering / Q000379:methods*; D054457:Tissue Scaffolds
D055396:Bone Morphogenetic Protein 2; D018786:Bone Substitutes; D006882:Hydroxyapatites