STUDY DESIGN: Prospective study to assess the enhancement of spine fusion using a tissue engineering construct consisting of bone marrow cells genetically modified by adenovirus (Ad) vector-encoding bone morphogenetic protein-7 (BMP-7) seeded onto an allograft scaffold in a rat model. OBJECTIVES: To evaluate Ad transgene expression at the fusion site and the effect of AdBMP-7-treatment on fusion rates, mechanical stability, microscopic anatomy, and bone formation rates. SUMMARY OF BACKGROUND DATA: Nonunion is a major complication of spine fusion. Gene transfer may be an effective method for locally overexpressing BMP-7, a gene important for bone formation and regeneration to enhance allograft spine fusion. MATERIALS AND METHODS: Bone marrow cells were treated with AdBMP-7 or Adbetagal (encoding the marker gene beta-galactosidase), AdNull (with no gene), or no vector and implanted with allograft in a site of posterior spine fusion. Marker gene expression was assessed up to 14 days after administration. Fusions were evaluated at 8 weeks. RESULTS: Ad gene expression was maximal on day 3, waning to background levels by 14 days. With AdBMP-7 treatment, radiographic fusion rate was 70% and mechanical fusion rate was 80% versus 0% by either parameter in control groups. Fused AdBMP-7-treated spines had a 2.5-fold to 3.0-fold lower range of motion and 1.7-fold to 1.9-fold lower hysteresis than controls. Fusion masses of AdBMP-7-treated spines had the microscopic appearance of normal trabecular bone and showed a 23-fold higher uptake of fluorochrome indicating increased bone formation. CONCLUSIONS: Addition of AdBMP-7-modified marrow cells can enhance allograft spine fusion.
STUDY DESIGN: Prospective study to assess the enhancement of spine fusion using a tissue engineering construct consisting of bone marrow cells genetically modified by adenovirus (Ad) vector-encoding bone morphogenetic protein-7 (BMP-7) seeded onto an allograft scaffold in a rat model. OBJECTIVES: To evaluate Ad transgene expression at the fusion site and the effect of AdBMP-7-treatment on fusion rates, mechanical stability, microscopic anatomy, and bone formation rates. SUMMARY OF BACKGROUND DATA: Nonunion is a major complication of spine fusion. Gene transfer may be an effective method for locally overexpressing BMP-7, a gene important for bone formation and regeneration to enhance allograft spine fusion. MATERIALS AND METHODS: Bone marrow cells were treated with AdBMP-7 or Adbetagal (encoding the marker gene beta-galactosidase), AdNull (with no gene), or no vector and implanted with allograft in a site of posterior spine fusion. Marker gene expression was assessed up to 14 days after administration. Fusions were evaluated at 8 weeks. RESULTS: Ad gene expression was maximal on day 3, waning to background levels by 14 days. With AdBMP-7 treatment, radiographic fusion rate was 70% and mechanical fusion rate was 80% versus 0% by either parameter in control groups. Fused AdBMP-7-treated spines had a 2.5-fold to 3.0-fold lower range of motion and 1.7-fold to 1.9-fold lower hysteresis than controls. Fusion masses of AdBMP-7-treated spines had the microscopic appearance of normal trabecular bone and showed a 23-fold higher uptake of fluorochrome indicating increased bone formation. CONCLUSIONS: Addition of AdBMP-7-modified marrow cells can enhance allograft spine fusion.
Authors: David G Reynolds; Saad Shaikh; Mark Owen Papuga; Amy L Lerner; Regis J O'Keefe; Edward M Schwarz; Hani A Awad Journal: J Bone Miner Res Date: 2009-05 Impact factor: 6.741
Authors: Ashvin K Dewan; Rahul A Dewan; Nathan Calderon; Angie Fuentes; Zawaunyka Lazard; Alan R Davis; Michael Heggeness; John A Hipp; Elizabeth A Olmsted-Davis Journal: J Orthop Surg Res Date: 2010-08-21 Impact factor: 2.359
Authors: Sheela R Damle; Bernard A Rawlins; Oheneba Boachie-Adjei; Ronald G Crystal; Chisa Hidaka; Matthew E Cunningham Journal: HSS J Date: 2013-01-08