Efficient liver gene transfer with foamy virus vectors.
BACKGROUND
Liver gene transfer offers hope for the correction of genetic and acquired disorders. Efficient gene transfer in large animals can be obtained with hydrodynamic gene transfer (HGT), a method that can achieve sufficient levels of gene delivery.


METHODS
To test the relative efficiency between plasmid versus foamy virus (FV) vector-based liver gene transfer efficiency, we applied HGT in 4 juvenile pigs, using the same plasmid backbone, either naked or coated as a FV vector particle. Gene transfer efficiency and persistence of expression was assayed by PCR and real-time PCR, respectively, at 1 week and at 1 month after the infusions.


RESULTS
HGT was tolerated well and no adverse reactions were observed. Plasmid injections resulted in no detectable DNA sequences at 1 week. At the 1 month time point, 2/15 liver sections analyzed were positive for the presence of plasmid DNA. When FV vectors were infused under identical conditions, 18/28 (64.3%) of the liver samples were positive for the presence of vector sequences, and the expression levels reached 29.7 and 15.6% of the endogenous GAPDH levels in the injected and the adjacent liver lobes.


CONCLUSIONS
Our results indicate that medium-term therapeutic levels of gene expression can be obtained with FV vectors, an effect that can be attributed to the potential of the HGT procedure and to the natural affinity of FV vectors for hepatocytes.
Department of Surgery, University of Thessaly Medical School, Larisa, Greece.
Dimitris
D
Zacharoulis
Chris
C
Rountas
Michalis
M
Katsimpoulas
John
J
Morianos
Ilenia
I
Chatziandreou
George
G
Vassilopoulos
D000818:Animals; D018014:Gene Transfer Techniques; D015316:Genetic Therapy / Q000379:methods*; D005822:Genetic Vectors; D008099:Liver / Q000378:metabolism*; D008297:Male; D023421:Models, Animal; D010957:Plasmids / Q000235:genetics; D016133:Polymerase Chain Reaction; D060888:Real-Time Polymerase Chain Reaction; D016092:Spumavirus / Q000235:genetics*; D013552:Swine