Ectopic osteogenesis using adenoviral bone morphogenetic protein (BMP)-4 and BMP-6 gene transfer.
Bone morphogenetic proteins (BMPs) delivered on scaffolds can induce ectopic bone formation after subcutaneous injection. Adenoviral vectors (Ad) carrying BMP2, BMP7, and BMP9 cDNAs have been shown to produce bone through endochondral ossification. The present study was performed to elucidate the histological events leading to ectopic ossification for two novel first-generation adenoviral constructs encoding BMPs, AdBMP4 and AdBMP6. In vitro, the viral constructs produced and secreted the mature BMP4 and BMP6 proteins. In vivo, the calf muscles of athymic nude rats were injected with AdBMP4, AdBMP6, AdBMP2, or AdlacZ. Rats were sacrificed 3, 6, 9, 16, 21, 60, and 90 days postinjection. Whereas AdBMP4 produced ectopic bone through mechanisms similar to endochondral ossification, AdBMP6 seemed to induce bone by way of mechanisms similar to both intramembranous and endochondral ossification pathways. At the relatively low vector dose used in this study, AdBMP2 caused an initial recruitment of primitive mesenchymal cells, without further development to bone. From computed tomographic analysis, AdBMP6 produced the most rapid tissue calcification. The ultimate density of ectopic bone formed by AdBMP4 and AdBMP6 was comparable. The current study demonstrates that AdBMP4 and AdBMP6 are more potent than the prototypical osteogenic adenoviral vector AdBMP2 and seem to induce ectopic bone by different mechanisms.
Jane
John A
JA
Department of Neurosurgery, University of Virginia Health System, Charlottesville, Virginia 22908, USA. gah9r@virginia.edu
Dunford
Bradley A
BA
Kron
Adam
A
Pittman
Debra D
DD
Sasaki
Tsutomu
T
Li
Jin Zhong
JZ
Li
Hongwei
H
Alden
Tord D
TD
Dayoub
Hayan
H
Hankins
Gerald R
GR
Kallmes
David F
DF
Helm
Gregory A
GA
D000256:Adenoviridae; D000818:Animals; D055415:Bone Morphogenetic Protein 4; D055418:Bone Morphogenetic Protein 6; D019485:Bone Morphogenetic Proteins / Q000235:genetics / Q000378:metabolism*; D002460:Cell Line; D019902:Chondrocytes / Q000378:metabolism; D018014:Gene Transfer Techniques; D010011:Osteocytes / Q000378:metabolism; D010012:Osteogenesis / Q000235:genetics / Q000502:physiology*; D014057:Tomography, X-Ray Computed
C525811:Bmp4 protein, rat; C525818:Bmp6 protein, rat; D055415:Bone Morphogenetic Protein 4; D055418:Bone Morphogenetic Protein 6; D019485:Bone Morphogenetic Proteins