Gene transfer into the liver by plasmid injection into the portal vein combined with electroporation.

Abstract

We investigated the optimum conditions for gene transfer into the liver by injection of plasmid via the portal vein combined with electroporation. In anesthetized 7-week-old male Shionogi Wistar rats, a tapered 3Fr. catheter was inserted through a branch of the colonic vein and its tip was secured into the portal vein. After clamping the vessels around the right and caudal lobes of the liver, FITC-oligodeoxynucleotide (ODN), green fluorescence protein (GFP) plasmid, or pCAGGS-luciferase was injected into the right and caudal lobes during electroporation using electric pulses applied to the caudal lobe only. Transfected cells were identified by FITC-ODN and GFP fluorescence, and transfection efficacy was estimated by measurement of luciferase activity. FITC-ODN and GFP were detected in the caudal lobes of the liver. FITC-ODN was particularly present in hepatocytes surrounding the Glisson capsule and central veins, while GFP was detected in only hepatocytes surrounding the Glisson capsule. Luciferase activity in the liver was dependent on the plasmid concentration and voltage of the electric pulse, but independent of the volume of plasmid solution. Luciferase activity was limited in the right lobe, in which plasmid solution was injected but no electroporation was applied. Our results showed local expression of the induced gene at the electroporation site, suggesting it is potentially useful for liver function support during recovery after extensive liver surgery and for the treatment of chronic and/or diffuse liver diseases.