Angiographically guided utero-placental gene transfer in rabbits with adenoviruses, plasmid/liposomes and plasmid/polyethyleneimine complexes

We examined the feasibility of gene transfer to rabbit placenta using adeno viruses, plasmid/liposomes and plasmid/polyethyleneimine (PEI) complexes. P regnant New Zealand White rabbits (n = 17) were anesthetized and local gene transfer was done via a catheter inserted in uterine arteries under direct angiographic control. Either nuclear targeted LacZ adenoviruses (1.0 x 10( 10) p.f.u.), nuclear targeted LacZ plasmid (500 mug)/liposome (DOTMA:DOPE 1 :1) complexes or nuclear targeted LacZ plasmid (250 mug)/PEI (25 kDa) compl exes (charge ratio +/-4) were used. Animals were killed 3 days later and de tection of the transgene expression was done by X-gal staining and RT-PCR. Adenovirus-mediated gene transfer resulted in a high transfection efficienc y (34 +/- 10%) in placental trophoplastic cells. Very little, if any, trans fection was seen in fetal membranes. Plasmid/liposomes and plasmid/PEI comp lexes led to a very low (<0.01%) transfection efficiency in trophoblastic c ells, but some transfection was seen in fetal membranes. A total of 25 fetu ses were analyzed for the presence of transgene at the time of death. In mo st fetuses expression of the LacZ gene was below the sensitivity of the X-g al staining, but expression was detected by PCR in 50%, 50% and 42% of the analyzed fetuses after adenoviral, plasmid/PEI and plasmid/liposome gene tr ansfer, respectively. No major inflammatory changes were present in the tra nsfected placentas as analyzed by general histology and macrophage- and T c ell-specific immunostainings. We conclude that catheter-mediated intravascu lar gene transfer with adenoviruses can be used for the transfection of pla cental trophoplastic cells, but plasmid complexes are inefficient for this purpose. However, selective angiographically guided gene transfer also led to leakage of the vector to fetuses. Therefore, if gene therapy is develope d for the treatment of placental disorders, the gene-vector combination sho uld not be harmful to the fetus and the expression of the transgene should only occur in placenta.