title: Sonoporation increases therapeutic efficacy of inducible and constitutive BMP2/7 in vivo gene delivery.
abstract: An ideal novel treatment for bone defects should provide regeneration without autologous or allogenous grafting, exogenous cells, growth factors, or biomaterials while ensuring spatial and temporal control as well as safety. Therefore, a novel osteoinductive nonviral in vivo gene therapy approach using sonoporation was investigated in ectopic and orthotopic models. Constitutive or regulated, doxycycline-inducible, bone morphogenetic protein 2 and 7 coexpression plasmids were repeatedly applied for 5 days. Ectopic and orthotopic gene transfer efficacy was monitored by coapplication of a luciferase plasmid and bioluminescence imaging. Orthotopic plasmid DNA distribution was investigated using a novel plasmid-labeling method. Luciferase imaging demonstrated an increased trend (61% vs. 100%) of gene transfer efficacy, and micro-computed tomography evaluation showed significantly enhanced frequency of ectopic bone formation for sonoporation compared with passive gene delivery (46% vs. 100%) dependent on applied ultrasound power. Bone formation by the inducible system (83%) was stringently controlled by doxycycline in vivo, and no ectopic bone formation was observed without induction or with passive gene transfer without sonoporation. Orthotopic evaluation in a rat femur segmental defect model demonstrated an increased trend of gene transfer efficacy using sonoporation. Investigation of DNA distribution demonstrated extensive binding of plasmid DNA to bone tissue. Sonoporated animals displayed a potentially increased union rate (33%) without extensive callus formation or heterotopic ossification. We conclude that sonoporation of BMP2/7 coexpression plasmids is a feasible, minimally invasive method for osteoinduction and that improvement of bone regeneration by sonoporative gene delivery is superior to passive gene delivery.
authors.affiliation: 1 Ludwig Boltzmann Institute for Experimental and Clinical Traumatology, AUVA Research Center, Austrian Cluster for Tissue Regeneration, European Institute of Excellence on Tissue Engineering and Regenerative Medicine Research (Expertissues EEIG) , Vienna-Branch, 1200 Vienna, Austria .
authors.forename: Georg A
authors.initials: GA
authors.lastname: Feichtinger
authors.forename: Anna T
authors.initials: AT
authors.lastname: Hofmann
authors.forename: Paul
authors.initials: P
authors.lastname: Slezak
authors.forename: Sebastian
authors.initials: S
authors.lastname: Schuetzenberger
authors.forename: Martin
authors.initials: M
authors.lastname: Kaipel
authors.forename: Ernst
authors.initials: E
authors.lastname: Schwartz
authors.forename: Anne
authors.initials: A
authors.lastname: Neef
authors.forename: Nikolitsa
authors.initials: N
authors.lastname: Nomikou
authors.forename: Thomas
authors.initials: T
authors.lastname: Nau
authors.forename: Martijn
authors.initials: M
authors.lastname: van Griensven
authors.forename: Anthony P
authors.initials: AP
authors.lastname: McHale
authors.forename: Heinz
authors.initials: H
authors.lastname: Redl
mesh_terms: D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000235:genetics* / Q000378:metabolism; D055419:Bone Morphogenetic Protein 7 / Q000235:genetics* / Q000378:metabolism; D001861:Bone Regeneration; D001842:Bone and Bones / Q000000981:diagnostic imaging; D004318:Doxycycline / Q000494:pharmacology; D005260:Female; D050723:Fractures, Bone / Q000628:therapy; D015870:Gene Expression / Q000187:drug effects; D018014:Gene Transfer Techniques; D015316:Genetic Therapy; D005822:Genetic Vectors / Q000235:genetics / Q000378:metabolism* / Q000627:therapeutic use; D008297:Male; D051379:Mice; D008819:Mice, Nude; D018482:Muscle, Skeletal / Q000473:pathology; D010012:Osteogenesis; D051381:Rats; D017207:Rats, Sprague-Dawley; D013010:Sonication; D055153:Stem Cell Niche; D014057:Tomography, X-Ray Computed
chemical_list: D055396:Bone Morphogenetic Protein 2; D055419:Bone Morphogenetic Protein 7; D004318:Doxycycline