Ureteral gene transfer to porcine induced strictures using endourologic delivery of an adenoviral vector

Purpose: Direct gene transfer to the ureter is an attractive approach to pr event restenosis after endourologic management of ureteral strictures. We t herefore assessed the rationale for adenovirus-mediated gene transfer in th e ureter in vitro and in vivo using a porcine model. Materials and Methods: Primary cultures of porcine ureteral epithelial and stromal cells were infected with an adenoviral solution carrying a nucleus- targeted P-Galactosidase (p-Gal) reporter gene (6.5 10(8) pfu/ml.), In addi tion, in order to mimic the human clinical situation, we have devised a mod el of thermally-induced stricture in porcine ureter which produced tight fi brotic stenosis within 8 days. Using a purposely designed channelled balloo n catheter prototype, these strictures were endoscopically dilated and then instilled with the same P-Gal adenoviral construction. Results: Application of recombinant adenovirus harboring a nucleus-targeted P-Gal reporter gene to cultured porcine urothelial and stromal cells resul ted in high transduction efficiency of up to 99% and 84% respectively. Seve n days after infection, X-Gal staining of the strictured ureters demonstrat ed transfection up to 2 mm, depth within the fibrosis, confirmed by polymer ase chain reaction (PCR) analysis. Adjacent and distal spread of the virus was excluded by histochemistry (X-Gal staining) and PCR. Conclusion: This data represents the first report of adenovirus-mediated ge ne transfer to the ureter. It remained site specific by endourologic retrog rade clinically applicable techniques.