title: The enhancement of bone regeneration by gene activated matrix encoding for platelet derived growth factor.
abstract: Gene therapy using non-viral vectors that are safe and efficient in transfecting target cells is an effective approach to overcome the shortcomings of protein delivery of growth factors. The objective of this study was to develop and test a non-viral gene delivery system for bone regeneration utilizing a collagen scaffold to deliver polyethylenimine (PEI)-plasmid DNA (pDNA) [encoding platelet derived growth factor-B (PDGF-B)] complexes. The PEI-pPDGF-B complexes were fabricated at amine (N) to phosphate (P) ratio of 10 and characterized for size, surface charge, and in vitro cytotoxicity and transfection efficacy in human bone marrow stromal cells (BMSCs). The influence of the complex-loaded collagen scaffold on cellular attachment and recruitment was evaluated in vitro using microscopy techniques. The in vivo regenerative capacity of the gene delivery system was assessed in 5 mm diameter critical-sized calvarial defects in Fisher 344 rats. The complexes were ~100 nm in size with a positive surface charge. Complexes prepared at an N/P ratio of 10 displayed low cytotoxicity as assessed by a cell viability assay. Confocal microscopy revealed significant proliferation of BMSCs on complex-loaded collagen scaffolds compared to empty scaffolds. In vivo studies showed significantly higher new bone volume/total volume (BV/TV) % in calvarial defects treated with the complex-activated scaffolds following 4 weeks of implantation (14- and 44-fold higher) when compared to empty defects or empty scaffolds, respectively. Together, these findings suggest that non-viral PDGF-B gene-activated scaffolds are effective for bone regeneration and are an attractive gene delivery system with significant potential for clinical translation.
authors.affiliation: Department of Periodontics, University of Iowa College of Dentistry, Iowa City, IA, USA. Electronic address: satheesh-elangovan@uiowa.edu.
authors.forename: Satheesh
authors.initials: S
authors.lastname: Elangovan
authors.forename: Sheetal R
authors.initials: SR
authors.lastname: D'Mello
authors.forename: Liu
authors.initials: L
authors.lastname: Hong
authors.forename: Ryan D
authors.initials: RD
authors.lastname: Ross
authors.forename: Chantal
authors.initials: C
authors.lastname: Allamargot
authors.forename: Deborah V
authors.initials: DV
authors.lastname: Dawson
authors.forename: Clark M
authors.initials: CM
authors.lastname: Stanford
authors.forename: Georgia K
authors.initials: GK
authors.lastname: Johnson
authors.forename: D Rick
authors.initials: DR
authors.lastname: Sumner
authors.forename: Aliasger K
authors.initials: AK
authors.lastname: Salem
mesh_terms: D000818:Animals; D001861:Bone Regeneration / Q000235:genetics*; D049109:Cell Proliferation; D002470:Cell Survival; D003094:Collagen / Q000737:chemistry; D004247:DNA; D015870:Gene Expression; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D005822:Genetic Vectors; D006801:Humans; D008297:Male; D059630:Mesenchymal Stem Cells; D018613:Microscopy, Confocal; D010957:Plasmids / Q000235:genetics; D010982:Platelet-Derived Growth Factor / Q000235:genetics* / Q000378:metabolism; D011094:Polyethyleneimine; D051381:Rats; D011916:Rats, Inbred F344; D054457:Tissue Scaffolds / Q000737:chemistry*; D014162:Transfection
chemical_list: D010982:Platelet-Derived Growth Factor; D011094:Polyethyleneimine; D003094:Collagen; D004247:DNA
keywords: Bone regeneration; Gene delivery; Plasmid DNA; Platelet derived growth factor; Polyethylenimine; Scaffold