title: AAV plasmid DNA simplifies liver-directed in vivo gene therapy: comparison of expression levels after plasmid DNA-, adeno-associated virus- and adenovirus-mediated liver transfection.
abstract: BACKGROUND
  Successful liver gene therapy depends on efficient gene transfer techniques and long-lasting gene expression after successful transfer. Over the last decades, important progress has been made with the introduction of viral vectors using animal models, although their use is hampered by a complex and costly preparation compared to the simple and cost-effective preparation of plasmid DNA. These problems become even more critical when considering the application of viral vectors in human gene therapy and gene therapy trials. In a previous study, we were able to show that the hydrodynamics-based gene transfer of plasmid-DNA, containing the adeno-associated-virus specific inverted terminal repeats (AAV-ITR), prolongs gene expression in the liver, although it remained unclear whether plasmid gene transfer could achieve similar expression levels compared to viral-vector gene transfer.
  
  
  METHODS
  Rat livers were transfected in-vivo with AAV-ITR-containing plasmid-DNA using a modified hydrodynamics-based procedure. Expression levels were monitored thereafter and compared with expression levels after viral-vector gene transfer.
  
  
  RESULTS
  A high and stable long-term expression was achieved after in vivo transfection of rat livers with AAV-ITR-containing plasmids. The expression course resembled that after AAV-mediated gene transfer, and the expression was at least as high, and lasted as long, compared to recombinant AAV-mediated gene transfer.
  
  
  CONCLUSIONS
  We consider AAV-ITR-containing plasmids as a simple and cost-effective alternative to recombinant viral vectors, especially for liver-directed gene therapy in rodents. With ongoing progress in gene transfer methods for naked DNA, these plasmids may also become a successful alternative to recombinant viral vectors in human gene therapy.
authors.affiliation: University Medical Center Regensburg, Department of Surgery, Regensburg, Germany. axel.doenecke@klinik.uni-regensburg.de
authors.forename: Axel
authors.initials: A
authors.lastname: Doenecke
authors.forename: Alexander
authors.initials: A
authors.lastname: Krömer
authors.forename: Marcus N
authors.initials: MN
authors.lastname: Scherer
authors.forename: Hans-Jürgen
authors.initials: HJ
authors.lastname: Schlitt
authors.forename: Edward K
authors.initials: EK
authors.lastname: Geissler
mesh_terms: D000256:Adenoviridae / Q000235:genetics; D000818:Animals; D004279:DNA, Viral / Q000235:genetics / Q000378:metabolism*; D000229:Dependovirus / Q000235:genetics; D015870:Gene Expression; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D006801:Humans; D057446:Hydrodynamics; D008099:Liver / Q000378:metabolism; D008297:Male; D010957:Plasmids / Q000235:genetics*; D051381:Rats; D011917:Rats, Inbred Lew; D020079:Terminal Repeat Sequences; D014162:Transfection / Q000379:methods*
chemical_list: D004279:DNA, Viral