title: Synthetic scaffold coating with adeno-associated virus encoding BMP2 to promote endogenous bone repair.
abstract: Biomaterial scaffolds functionalized to stimulate endogenous repair mechanisms via the incorporation of osteogenic cues offer a potential alternative to bone grafting for the treatment of large bone defects. We first quantified the ability of a self-complementary adeno-associated viral vector encoding bone morphogenetic protein 2 (scAAV2.5-BMP2) to enhance human stem cell osteogenic differentiation in vitro. In two-dimensional culture, scAAV2.5-BMP2-transduced human mesenchymal stem cells (hMSCs) displayed significant increases in BMP2 production and alkaline phosphatase activity compared with controls. hMSCs and human amniotic-fluid-derived stem cells (hAFS cells) seeded on scAAV2.5-BMP2-coated three-dimensional porous polymer Poly(ε-caprolactone) (PCL) scaffolds also displayed significant increases in BMP2 production compared with controls during 12 weeks of culture, although only hMSC-seeded scaffolds displayed significantly increased mineral formation. PCL scaffolds coated with scAAV2.5-BMP2 were implanted into critically sized immunocompromised rat femoral defects, both with or without pre-seeding of hMSCs, representing ex vivo and in vivo gene therapy treatments, respectively. After 12 weeks, defects treated with acellular scAAV2.5-BMP2-coated scaffolds displayed increased bony bridging and had significantly higher bone ingrowth and mechanical properties compared with controls, whereas defects treated with scAAV2.5-BMP2 scaffolds pre-seeded with hMSCs failed to display significant differences relative to controls. When pooled, defect treatment with scAAV2.5-BMP2-coated scaffolds, both with or without inclusion of pre-seeded hMSCs, led to significant increases in defect mineral formation at all time points and increased mechanical properties compared with controls. This study thus presents a novel acellular bone-graft-free endogenous repair therapy for orthotopic tissue-engineered bone regeneration.
authors.affiliation: Parker H. Petit Institute for Bioengineering and Bioscience, Georgia Institute of Technology, 315 Ferst Drive, Atlanta, GA 30332, USA. kennethmdupont@yahoo.com
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Dupont
authors.forename: Joel D
authors.initials: JD
authors.lastname: Boerckel
authors.forename: Hazel Y
authors.initials: HY
authors.lastname: Stevens
authors.forename: Tamim
authors.initials: T
authors.lastname: Diab
authors.forename: Yash M
authors.initials: YM
authors.lastname: Kolambkar
authors.forename: Masahiko
authors.initials: M
authors.lastname: Takahata
authors.forename: Edward M
authors.initials: EM
authors.lastname: Schwarz
authors.forename: Robert E
authors.initials: RE
authors.lastname: Guldberg
mesh_terms: D000653:Amniotic Fluid / Q000166:cytology; D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000235:genetics* / Q000378:metabolism; D001842:Bone and Bones / Q000187:drug effects* / Q000473:pathology*; D002113:Calcification, Physiologic / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D020099:Coated Materials, Biocompatible / Q000494:pharmacology*; D004247:DNA / Q000378:metabolism; D000229:Dependovirus / Q000187:drug effects / Q000235:genetics*; D005260:Female; D005269:Femur / Q000187:drug effects / Q000473:pathology; D006801:Humans; D059630:Mesenchymal Stem Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects; D011091:Polyesters / Q000494:pharmacology; D051381:Rats; D011923:Rats, Nude; D054457:Tissue Scaffolds / Q000737:chemistry*; D014161:Transduction, Genetic; D014945:Wound Healing / Q000187:drug effects*; D001616:beta-Galactosidase / Q000378:metabolism
chemical_list: D055396:Bone Morphogenetic Protein 2; D020099:Coated Materials, Biocompatible; D011091:Polyesters; C016240:polycaprolactone; D004247:DNA; D001616:beta-Galactosidase