Catheter-based adenovirus-mediated local intravascular gene delivery of a soluble TGF-b type II receptor using an Infiltrator in porcine cornary arter

Abstract

Enhanced extracellular matrix (ECM) accumulation is an important finding in human restenotic arterial neointima after angioplasty. Transforming growth factor β1(TGF-β1) is known to regulate the synthesis and turnover of a variety of ECM components, and may play an important role in restenosis. Recombinant adenoviral vector expressing an ectodomain of the TGF-β type II receptor fused to the human immunoglobulin Fc portion (AdTβ-ExR) inhibits the action of TGF-β probably either by adsorbing TGF-β or by acting as a dominant negative receptor. We carried out a catheter-based local adenovirus mediated gene delivery using an Infiltrator in porcine coronary arteries to know the pattern of gene expression, efficacy and procedural complications. Twenty four coronary arteries in 13 pigs were used for intravascular gene delivery by intramural injection with either AdTβ-ExR or adenovirus expressing b-galactosidase (AdCALacZ). Direct immunofluorescent staining and reverse transcription polymerase chain reaction (RTPCR) were used for detection of type II TGF-β receptor and its mRNA respectively. X-Gal histochemistry was performed to identify b-galactosidase. Both soluble TGF-β receptor and b-galactosidase were expressed locally in the media and adventita at injected arterial segments without any significant dissemination to remote area. Intravascular gene transfection performed with various titer of each adenoviral vector showed that AdTβ-ExR of 5x10(8) pfu and AdCALacZ of 2.5 x 10(8) pfu were the minimum titer for the expression of each transgene. Infiltration of CD3 positive T cells was detected by immunohistochemical staining in the area of each transgene expression, and tends to decrease over time after gene delivery. Pathological study of 24 treated arteries showed complications such as disruption of external elastic lamina with hemorrhage (n = 4), minimal disruption of internal elastic lamina and endothelial layer, and medial thickening. In conclusion, catheter-based local intravascular gene delivery of adenoviral vector is feasible and effective in a selected artery, but must be undertaken with caution due to possible lethal complications. Local delivery of soluble TGF-β type II receptor in this way may provide an effective intravascular gene therapy to inhibit TGF-β signal pathway without any significant systemic side effect.