title: Augmented healing of critical-size calvarial defects by baculovirus-engineered MSCs that persistently express growth factors.
abstract: Repair of large calvarial bony defects remains clinically challenging because successful spontaneous calvarial re-ossification rarely occurs. Although bone marrow-derived mesenchymal stem cells (BMSCs) genetically engineered with baculovirus (BV) for transient expression of osteogenic/angiogenic factors hold promise for bone engineering, we hypothesized that calvarial bone healing necessitates prolonged growth factor expression. Therefore, we employed a hybrid BV vector system whereby one BV expressed FLP while the other harbored the BMP2 (or VEGF) cassette flanked by Frt sequences. Transduction of rabbit BMSCs with the FLP/Frt-based BV vector led to FLP-mediated episome formation, which not only extended the BMP2/VEGF expression beyond 28 days but augmented the BMSCs osteogenesis. After allotransplantation into rabbits, X-ray, PET/CT, μCT and histological analyses demonstrated that the sustained BMP2/VEGF expression remarkably ameliorated the angiogenesis and regeneration of critical-size (8 mm) calvarial defects, when compared with the group implanted with BMSCs transiently expressing BMP2/VEGF. The prolonged expression by BMSCs accelerated the bone remodeling and regenerated the bone through the natural intramembranous pathway, filling ≈83% of the area and ≈63% of the volume in 12 weeks. These data implicated the potential of the hybrid BV vector to engineer BMSCs for sustained BMP2/VEGF expression and the repair of critical-size calvarial defects.
authors.affiliation: Department of Chemical Engineering, National Tsing Hua University, Hsinchu 300, Taiwan.
authors.forename: Chin-Yu
authors.initials: CY
authors.lastname: Lin
authors.forename: Yu-Han
authors.initials: YH
authors.lastname: Chang
authors.forename: Chun-Yu
authors.initials: CY
authors.lastname: Kao
authors.forename: Chia-Hsin
authors.initials: CH
authors.lastname: Lu
authors.forename: Li-Yu
authors.initials: LY
authors.lastname: Sung
authors.forename: Tzu-Chen
authors.initials: TC
authors.lastname: Yen
authors.forename: Kun-Ju
authors.initials: KJ
authors.lastname: Lin
authors.forename: Yu-Chen
authors.initials: YC
authors.lastname: Hu
mesh_terms: D000818:Animals; D016367:Baculoviridae / Q000235:genetics; D055396:Bone Morphogenetic Protein 2 / Q000096:biosynthesis / Q000235:genetics; D001861:Bone Regeneration / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D016723:Bone Remodeling / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D005260:Female; D015870:Gene Expression; D006133:Growth Substances / Q000096:biosynthesis / Q000235:genetics*; D008422:Materials Testing; D045164:Mesenchymal Stem Cell Transplantation / Q000379:methods*; D059630:Mesenchymal Stem Cells / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects / Q000235:genetics / Q000502:physiology; D011817:Rabbits; D011994:Recombinant Proteins / Q000096:biosynthesis / Q000235:genetics; D012886:Skull / Q000293:injuries* / Q000473:pathology / Q000601:surgery; D054457:Tissue Scaffolds; D042461:Vascular Endothelial Growth Factor A / Q000096:biosynthesis / Q000235:genetics
chemical_list: D055396:Bone Morphogenetic Protein 2; D006133:Growth Substances; D011994:Recombinant Proteins; D042461:Vascular Endothelial Growth Factor A