HIGH-EFFICIENCY GENE-TRANSFER TO AUTOLOGOUS RABBIT JUGULAR-VEIN GRAFTS USING ADENOVIRUS-TRANSFERRIN POLYLYSINE-DNA COMPLEXES/

Within the first year, 15-20% of coronary artery saphenous bypass vein grafts (SVGs) occlude because of thrombosis or progressive intimal hy perplasia. One potential new strategy to reduce this complication woul d be to introduce antithrombotic or antiproliferative genes in vein gr afts before implantation. The success of this approach requires an eff icient DNA delivery system. In the present study we tested the feasibi lity of using adenovirus-transferrin/polylysine-DNA complexes (TfAdpl/ DNA) to achieve high-efficiency gene transfer into vascular interposit ion vein grafts. All studies used the Escherichia coli LacZ (beta-gala ctosidase [beta-Gal]) reporter gene under the control of the cytomegal ovirus (CMV) earlier promoter and enhancer (pCMV/LacZ). Autologous rab bit jugular vein segments were incubated ex vivo for 60 min in a solut ion of TfAdpl/DNA complexes (1.2 x 10(10) biotinylated adenovirus part icles, 2,430 ng of streptavindylated polylysine. 10 mu g of plasmid DN A, and 9 mu g of transferrin-polylysine per mi), and then reimplanted across the ligated right carotid artery. Control veins were incubated in TfAdpl solution in which DNA was omitted. A total of six grafts wer e treated with TfAdpl/DNA, and two grafts were treated with TfAdpl. Ve ins were harvested 3 (n = 3) and 7 (n = 3) days later and beta-Gal act ivity was determined by X-Gal chromogen staining. All six TfAdpl/DNA-t reated grafts stained intensely blue, whereas control grafts were nega tive. Microscopic examination of serial sections revealed intracellula r blue granules consistent with beta-Gal activity to be present in all of the endothelial cells and in numerous medial and advential cells. beta-Gal activity appeared to be stable over the 7 days. From these da ta, we conclude that ex vivo gene therapy of vein segments prior to re implantation using TfAdpl/DNA complexes is practical. Further studies will be needed to determine the long-term effects of TfAdpl/DNA exposu re on vein grafts and whether graft patency can be improved by the int roduction of antithrombotic and/or antiproliferative genes.