title: Self-complementary AAV2.5-BMP2-coated femoral allografts mediated superior bone healing versus live autografts in mice with equivalent biomechanics to unfractured femur.
abstract: Structural allografts used for critical bone defects have limited osteogenic properties for biointegration. Although ex vivo tissue-engineered constructs expressing bone morphogenetic protein-2 (BMP2) have demonstrated efficacy in critical defect models, similar success has not been achieved with off-the-shelf acellular approaches, including allografts coated with freeze-dried single-stranded adeno-associated virus (ssAAV-BMP2). To see whether the self-complementary AAV serotype 2.5 vector (scAAV2.5-BMP2) could overcome this, we performed side-by-side comparisons in vitro and in the murine femoral allograft model. Although ssAAV-BMP2 was unable to induce BMP2 expression and differentiation of C3H10T1/2 cells in culture, scAAV2.5-BMP2 transduction led to dose-dependent BMP2 expression and alkaline phosphatase activity, and displayed a 25-fold increased transduction efficiency in vivo. After 6 weeks, the ssAAV-BMP2 coating failed to demonstrate any significant effects. However, all allografts coated with 10(10) scAAV2.5-BMP2 formed a new cortical shell that was indistinguishable to that formed by live autografts. Additionally, coated allografts experienced reduced resorption resulting in a threefold increase in graft bone volume versus autograft. This led to biomechanical superiority versus both allografts and autografts, and equivalent torsional rigidity to unfractured femur. Collectively, these results demonstrate that scAAV2.5-BMP2 coating overcomes the major limitations of structural allografts, which can be used to heal critical defects of any size.
authors.affiliation: The Center for Musculoskeletal Research, University of Rochester, Rochester, New York, USA.
authors.forename: Cemal
authors.initials: C
authors.lastname: Yazici
authors.forename: Masahiko
authors.initials: M
authors.lastname: Takahata
authors.forename: David G
authors.initials: DG
authors.lastname: Reynolds
authors.forename: Chao
authors.initials: C
authors.lastname: Xie
authors.forename: R Jude
authors.initials: RJ
authors.lastname: Samulski
authors.forename: Jade
authors.initials: J
authors.lastname: Samulski
authors.forename: E Jeffrey
authors.initials: EJ
authors.lastname: Beecham
authors.forename: Arthur A
authors.initials: AA
authors.lastname: Gertzman
authors.forename: Mark
authors.initials: M
authors.lastname: Spilker
authors.forename: Xinping
authors.initials: X
authors.lastname: Zhang
authors.forename: Regis J
authors.initials: RJ
authors.lastname: O'Keefe
authors.forename: Hani A
authors.initials: HA
authors.lastname: Awad
authors.forename: Edward M
authors.initials: EM
authors.lastname: Schwarz
mesh_terms: D000818:Animals; D001696:Biomechanical Phenomena; D055396:Bone Morphogenetic Protein 2 / Q000378:metabolism*; D001862:Bone Resorption / Q000473:pathology / Q000517:prevention & control; D016025:Bone Transplantation / Q000379:methods*; D002454:Cell Differentiation; D002460:Cell Line; D000229:Dependovirus / Q000235:genetics / Q000378:metabolism*; D005260:Female; D005269:Femur / Q000637:transplantation*; D059630:Mesenchymal Stem Cells; D051379:Mice; D008810:Mice, Inbred C57BL; D013848:Thigh; D023822:Tissue Engineering / Q000379:methods; D054159:Torsion, Mechanical; D014184:Transplantation, Homologous / Q000379:methods
chemical_list: C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2