Adenovirus-mediated in utero gene transfer in mice and guinea pigs: Tissuedistribution of recombinant adenovirus determined by quantitative TaqMan-polymerase chain reaction assay

Fetal somatic cell gene therapy could become an attractive solution for som e congenital genetic diseases or the disorders which manifest themselves du ring the fetal period. We performed adenovirus-mediated gene transfer to mi ce and guinea pig fetuses in utero and evaluated the efficiency of gene tra nsfer by histochemical analysis and a quantitative TaqMan-polymerase chain reaction (TaqMan-PCR) assay. We first injected a replication-deficient reco mbinant adenovirus containing the Escherichia coil LacZ gene driven by a CA C: promoter (AxCALacZ) into pregnant mice through the amniotic space, place nta, or intraperitoneal space of the fetus, Histochemical analysis showed l imited transgene expression in fetal tissues, We then administered AxCALacZ to guinea pig fetuses in the late stage of pregnancy through the umbilical vein. The highest P-galactosidase expression was observed in liver followe d by moderate expression in heart, spleen, and adrenal gland. The transgene expression was also present in kidney, intestine, and placenta 60 a lesser degree. No positively stained cells were observed in lung, muscle, or panc reas except in the vascular endothelium of these organs. Quantitative measu rement of recombinant adenoviral DNA by the TaqMan-PCR assay showed that th e vast majority of the injected viruses was present in liver. The current s tudy indicated that adenovirus-mediated gene transfer into guinea pig fetus through the umbilical vein is feasible and results in efficient transgene expression in fetal tissues. The experimental procedures using pregnant gui nea pigs might serve as a good experimental model for in utero gene transfe r. Since our TaqMan-PCR assay detects the LacZ gene, one of the most widely used reporter genes, it may be generally applicable to adenovirus quantifi cation in various gene transfer experiments. (C) 2000 Academic Press.