EXPRESSION OF NAKED PLASMID DNA INJECTED INTO THE AFFERENT AND EFFERENT VESSELS OF RODENT AND DOG LIVERS

A variety of reporter genes within plasmid constructs were injected in to the afferent and efferent vessels of the liver in mice, rats, and d ogs, Efficient plasmid expression was obtained following delivery via the portal vein, the hepatic vein, and the bile duct, The use of hyper osmotic injection solutions and occlusion of the blood outflow from th e liver substantially increased the expression levels, Combining these surgical approaches with improved plasmid vectors enabled uncommonly high levels of foreign gene expression in which over 15 mu g of lucife rase protein/liver was produced in mice and over 50 mu g in rats, Equa lly high levels of beta-galactosidase (beta-Gal) expression were obtai ned, in that over 5% of the hepatocytes had intense blue staining, Exp ression of luciferase or beta-Gal was evenly distributed in hepatocyte s throughout the entire liver when either of the three routes were inj ected, Peri-acinar hepatocytes were preferentially transfected when th e portal vein was injected in rats, These levels of foreign gene expre ssion are among the highest levels obtained with nonviral vectors, Rep etitive plasmid administration through the bile duct led to successive events of foreign gene expression, The integration of these findings into laboratory and clinical protocols is discussed.