P251	In vivo suppression of intimal hyperplasia in vein grafts by non-viral, electroporation mediated, gene transfer of ATF.BPTI, a cell-surface directed plasmin inhibitor.
2D.Eefting, 1M.De Vries, 1J.Grimbergen, 1J-W.Lardenoye, 2H.Van Bockel, 1P.Quax
1TNO Quality of Life, Leiden, NL; 2Leiden University Medical Center, Leiden, NL.

Overexpression of protease inhibitors is thought to reduce vascular remodeling and neointima formation. The most commonly used Adenovirus mediated gene transfer has major disadvantages such as immune responses and short term expression. As an alternative, here we use an electroporation based, non-viral, gene transfer method to study the effect of overexpression of ATF.BPTI, a cell-surface directed plasmin inhibitor, on vein graft disease in mice. The hybrid protein ATF.BPTI consists of the aminoterminal fragment (ATF) receptor binding part of urokinase-type plasminogen activator, linked to bovine pancreas trypsin inhibitor (BPTI), a potent inhibitor of plasmin. ATF.BPTI acts as a cell-surface binding plasmin inhibitor, which inhibits proteolysis, matrix degeneration and cell migration in the direct cell environment. Here, we study the effect of electroporation mediated overexpression of ATF.BPTI on intimal hyperplasia in a murine model for vein graft disease, in which a venous interposition of a donor mouse is placed in the carotid artery of a recipient mouse. One day prior to vein graft surgery, pcDNA3.1-ATF.BPTI or a Luciferase control plasmid was electroporated in both calf muscles of hypercholesterolemic ApoE3Leiden mice (n=7). Seven days after electroporation, ATF.BPTI protein was detectable in the plasma, with levels between 5 to 10 ng/ml. Morphometric analysis on sections of grafts harvested four weeks after surgery and electroporation, shows a 71% reduction of neointimal surface in the ATF.BPTI treated group as compared to the control group treated with the luciferase vector (p<0.005). Conclusion These data demonstrate that intramuscular electroporation in the calf muscle results in circulating serum levels of ATF.BPTI, that are sufficient to inhibit neointima formation in distant vein grafts. Because of the high and prolonged gene expression after a single intramuscular electroporation, this gene delivery method is very suitable to investigate the effect of therapeutic genes. Therefore, electroporation of “therapeutic” genes like ATF.BPTI, is a promising and an attractive alternative for viral gene delivery, to prevent vein graft disease.

Copyright © 2005 S. Karger AG, Basel. Any further use of this abstract requires written permission from the publisher.