¹Department of Pediatrics, Section of Medical and Molecular Genetics, University of Arizona Health Sciences Center, 1501 N Campbell Avenue, Tucson, Arizona 85724, USA

²Department of Medicine, Section of Renal Disease, University of Arizona Health Sciences Center, 1501 N Campbell Avenue, Tucson, Arizona 85724, USA

To develop gene therapy targeted to the kidney, we compared three different routes of liposome-mediated gene delivery to the kidney in mice, ie intra-renal-pelvic, intra-renal-arterial, and intra-renal-parenchymal injections. A plasmid construct, pCMVgal, containing a cytomegalovirus (CMV) immediate-early gene promoter and a -galactosidase reporter gene was mixed with a 1:1 liposome mixture of N[1-(2,3-dioleoyloxy)propyl]-N,N,trimethylammonium chloride (DOTMA)/dioleoyl phosphatidyl ethanolamine (DOPE). The pCMVgal-liposome complex was injected into the left kidney via three different routes. The efficacy of gene transfer was assessed using 5-bromo-4-chloro-3-indolyl -d-galactopyranoside (X-gal) staining on frozen kidney sections 3 to 42 days after injections. Cells with -galactosidase activity were detected in the cortex and outer medulla in both intra-renal-pelvic and intra-renal-arterial groups, but not in the intra-renal-parenchymal group or in the contralateral noninjected kidney. Evidence of gene transfer was observed only in tubular epithelial cells, but not in glomerular, vascular, or interstitial compartments. The levels of -galactosidase expression started to decrease 3 weeks after injection. The gene transfer in the kidney was not associated with nephrotoxicity as assessed by blood urea nitrogen levels and renal histology. We conclude that both intra-renal-pelvic and intra-renal-arterial injections provide a transient gene transfer to the renal tubular cells and are suitable routes for kidney-targeted gene therapy.

gene therapy; kidney; -galactosidase; lipofection