A novel surgical organ perfusion method for effective ex vivo and in vivo gene transfer into renal glomerular cells

In an attempt to develop gene therapy for Alport syndrome, we have evaluated surgical methods for gene transfer into pig kidneys. For gene transfer we used an adenovirus expressing the Escherichia coli beta-galactosidase gene as a reporter gene. The viral preparation was first infused in vivo into the porcine renal artery. Then explanted kidneys were perfused ex vivo at body temperature for 12 hours with the viral solution and, finally the kidney perfusions were carried out in vivo via laparotomy for 60 and 120 minutes. Gene transfer was determined visually on histological cryosections after 5-bromo-4-chloro-3-indoyl-beta-galactopyranoside (X-gal) and periodic acid-Schiff (PAS) staining. Perfusion of whole porcine kidneys ex vivo resulted in strong expression in about 80% of glomeruli. The in vivo kidney perfusion via laparotomy for 120 minutes resulted in reporter gene expression of about 75% of the glomeruli examined after 4 days. Expression was observed almost exclusively in glomeruli, while little if any expression was found in other renal structures. The present results suggest that operatively performed kidney perfusion may be used for gene transfer in treatment of glomerular disease. This surgical approach may also prove useful for somatic gene therapy of other organs.