Nonviral and viral gene transfer to the kidney in the context of transplantation.
OBJECTIVE
Local modulation of the immune response through genetic manipulation of the graft is an attractive novel approach to overcome the toxicity of immunosuppressive therapy to prevent acute graft rejection. We have previously reported that the cationic polymer polyethylenimine 25k (PEI 25k) transduced reporter genes when injected into the renal artery, but with a low transfection efficiency. Here we compare the risk/benefit profiles of such a nonviral versus a viral technique of gene transfer to the kidney in the context of renal transplantation.


METHODS
Donor kidneys from Lewis rats were perfused in a closed circuit with an artificial cell-free medium containing PEI 25k complexed to an expression vector coding for the beta-galactosidase (beta-gal) gene and subsequently transplanted in a syngeneic animal. In a second set of experiments, donor kidneys were injected or perfused with a replication-deficient adenovirus encoding the beta-gal gene (AdCMV. beta-gal; 1 x 10(9) plaque-forming units) before transplantation.


RESULTS
Perfusion of the kidney with PEI 25k/DNA complexes resulted in large areas of hypoperfusion characterized by injured glomeruli and tubuli, capillary thrombosis and accumulation of C3 in glomerular capillaries. Reperfusion of the kidney was achieved by lowering the PEI 25k/DNA ratio, but no detectable transfection was observed. In animals receiving adenovirus, the beta-gal activity increased with time and was localized mainly in proximal and distal tubular cells, as documented by beta-gal histochemistry and in situ hybridization. A significantly increased expression of beta-gal was achieved by perfusion of the kidney with AdCMV.beta-gal before transplantation, beta-gal staining mainly localizing in proximal and distal tubular cells.


CONCLUSIONS
Unlike nonviral methods of gene delivery, adenovirus-mediated gene transfer to the kidney offers exciting perspectives for the development of molecular medicine in the field of organ transplantation.
Mario Negri Institute for Pharmacological Research, Bergamo, Italy. abenigni@irfmn.mnegri.it
A
A
Benigni
S
S
Tomasoni
J
J
Lutz
S
S
Amuchastegui
M C
MC
Capogrossi
G
G
Remuzzi
D000256:Adenoviridae / Q000235:genetics*; D000818:Animals; D002412:Cations; D015967:Gene Expression Regulation, Viral; D018014:Gene Transfer Techniques; D017930:Genes, Reporter; D017403:In Situ Hybridization; D066298:In Vitro Techniques; D016030:Kidney Transplantation; D008297:Male; D010477:Perfusion; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D011917:Rats, Inbred Lew; D001616:beta-Galactosidase / Q000235:genetics
D002412:Cations; D012333:RNA, Messenger; D001616:beta-Galactosidase