Gene transfer to human placenta ex vivo:: A novel application of dual perfusion of human placental cotyledon

OBJECTIVE: The purpose of this study was to determine whether the transfer of a marker gene in dual recirculating human placental perfusion is feasible and whether the transgene production is detectable by X-Gal histochemistry. STUDY DESIGN: Four term human placentas were perfused for 9 to 16 hours in a dual perfusion chamber. At the beginning of each experiment, an adenoviral vector that carried P-galactosidase gene was added to the maternal perfusate that was entering the intervillous space; at the end, the placental tissues were analyzed for beta-galactosidase activity by X-Gal staining. RESULTS: Adenovirus-mediated gene transfer resulted in a 0.5% to 1% gene transfer efficiency in placental trophoblastic cells after 9 hours of perfusion, whereas the gene transfer efficiency was much higher, to 5% after 16 hours of perfusion. When postperfusion tissue explant cultures were analyzed for beta-galactosidase expression 56 hours after the perfusion, the transfection rate was as high as 11%. CONCLUSION: Perfused human placenta can be efficiently transfected with adenoviral vectors, and the expression of the transgene can be detected in the trophoblastic cells. This system can be used for the optimization and analysis of gene transfer conditions to human placenta without any risk to the fetus.