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Gene and Cell-Based BMP-2 and -6 Gene Therapy For Equine Bone Regeneration

Ishihara, Akikazu
http://rave.ohiolink.edu/etdc/view?acc_num=osu1258748598

Abstract Details

2009, Doctor of Philosophy, Ohio State University, Veterinary Biosciences.
Fracture is still a life-threatening disorder in horses, but current treatment options have not provided satisfying outcomes for complicated and catastrophic fractures in horses. Cell-mediated and direct gene therapies have provided numerous promising results in recent years and may become as practical alternative solutions for the potential treatments of equine bone repair and regeneration. We demonstrated that sufficient gene transfer could be achieved by using an adenoviral (Ad) vector in equine cells. High vector dosages could be used in equine cells because of relative resistance to cytotoxicity in these cells compared to a human cell line. We evaluated the healing of equine metatarsal osteotomies and ostectomies in response to delayed percutaneous injection of adenoviral bone morphogenetic protein-2 (Ad-BMP2), Ad-BMP6, or beta-galactosidase protein vector control (Ad-LacZ) administered 14 days after surgery. Radiographic and quantitative computed tomographic (qCT) assessment of bone formation indicated greater and earlier mineralized callus in the bone defects injected with Ad-BMP2 or Ad-BMP6. Peak torque to failure and torsional stiffness were greater in osteotomies treated with Ad-BMP2 than Ad-BMP6, and both Ad-BMP-2 and Ad-BMP6 treated osteotomies were greater than Ad-LacZ or untreated osteotomies. Gene expression of ostectomy mineralized callus 8 weeks after surgery indicated upregulation of genes related to osteogenesis compared to intact metatarsal bone. These results demonstrated a greater relative potency of Ad-BMP2 over Ad-BMP6 in accelerating osteotomy healing. We also evaluated the healing of equine metacarpal/metatarsal osteotomies in response to the percutaneous injection of autologous dermal fibroblasts (DFb) genetically engineered to secrete BMP2 or demonstrate green fluorescent protein (GFP) gene expression administered 14 days after surgery. Radiographic assessment of bone formation indicated greater and earlier healing of bone defects treated with DFb with BMP2 gene augumentation. The qCT and biomechanical testing revealed greater mineralized callus and torsional strength of DFb-BMP2 treated bone defects. On the histologic evaluation, the bone defects with DFb-BMP2 implantation had greater formation of mature cartilage and bone nodules within the osteotomy gap and greater mineralization activity on osteotomy edges. In addition, we compared the DFb-mediated and direct adenoviral vector delivery of BMP2 for relative efficacy in bone regeneration. Equine rib drill defects were treated by percutaneous injection of either DFb-BMP2 or Ad-BMP2 vector. At week 6, both of the DFb-BMP2- and Ad-BMP2-treated rib defects had greater bone filling volume and mineral density, with DFb-BMP2 inducing greater bone volume and maturity in cortical bone aspect of the defect than Ad-BMP2. The transplantation of DFb alone induced modest bone formation. Increased mineral density and bone turnover were evident in the cortical and cancellous bone directly adjacent to the healing drill defects treated with either DFb-BMP2 or Ad-BMP2. Additionally, we demonstrated the safety of BMP2 gene therapy for articular fracture, because the direct intra-articular administrations of Ad-BMP2 did not cause of mineralization or ossification of articular cartilage and synovium tissues. In concert, both cell-mediated and direct BMP2 gene therapy may be considered as a potential treatment for various types of fractures and bone defects.
Alicia Bertone (Advisor)
Alan Litsky (Committee Member)
Steve Weisbrode (Committee Member)
Bartlett Jeffrey (Committee Member)
Veterinary Services

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Citations

  • Ishihara, A. (2009). Gene and Cell-Based BMP-2 and -6 Gene Therapy For Equine Bone Regeneration [Doctoral dissertation, Ohio State University]. OhioLINK Electronic Theses and Dissertations Center. http://rave.ohiolink.edu/etdc/view?acc_num=osu1258748598

    APA Style (7th edition)

  • Ishihara, Akikazu. Gene and Cell-Based BMP-2 and -6 Gene Therapy For Equine Bone Regeneration. 2009. Ohio State University, Doctoral dissertation. OhioLINK Electronic Theses and Dissertations Center, http://rave.ohiolink.edu/etdc/view?acc_num=osu1258748598.

    MLA Style (8th edition)

  • Ishihara, Akikazu. "Gene and Cell-Based BMP-2 and -6 Gene Therapy For Equine Bone Regeneration." Doctoral dissertation, Ohio State University, 2009. http://rave.ohiolink.edu/etdc/view?acc_num=osu1258748598

    Chicago Manual of Style (17th edition)

osu1258748598
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© 2009, all rights reserved.
This open access ETD is published by The Ohio State University and OhioLINK.