Adenovirus-mediated gene transfer in the midgestation fetal mouse

Background. The development of strategies for gene transfer in utero will m ake possible the amelioration, and eventually the cure, of genetic diseases associated with pre- and postnatal morbidity and mortality. We have develo ped a murine model for in utero, intrahepatic, adenovirus-mediated gene tra nsfer in Day 15 fetuses and compared the level and distribution of lucifera se reporter gene expression in newborns with those observed in adult animal s injected intravenously. Material and methods. CD-1 fetuses underwent intrahepatic injection on Day 15 of gestation with 1 x 10(7) particle-forming units (PFU) of an E1- and E 3-deleted recombinant adenovirus containing the luciferase reporter gene or with normal saline. At birth, pups were euthanized, and the brain, heart, intestine, liver, lungs, and spleen harvested and analyzed for luciferase a ctivity. Results. Two adenovirus-injected litters proceeded to term and one female a borted. Tissues from 10 newborn mice in the experimental group and 5 newbor ns in the control group were analyzed; tissues from the remaining newborns were reserved for other studies. High-level luciferase expression was detec ted in all adenovirus-injected newborn livers. Lower levels of luciferase a ctivity were detected in distant organs. Hepatic toxicity as determined by serum transaminase elevations was observed in adult, but not in newborn mic e previously injected with the adeno-luciferase virus. Conclusions. In utero intrahepatic gene delivery with adenoviral vectors in the developing murine fetus is feasible and produces high-level gene expre ssion. These studies suggest that viral and nonviral gene delivery vectors may be useful in the development of future approaches to prenatal treatment of genetic disorders. (C) 1999 Academic Press.