Long-term therapeutic levels of human alpha-1 antitrypsin in plasma after hydrodynamic injection of nonviral DNA

The transfection efficacy of several vectors containing the full genomic hAAT gene with its natural promoter (pTG7101) and others containing the cDNA of hAAT gene driven by cytomegalovirus immediate-early promoter or the 0.5 kb upstream of hAAT gene sequence has been studied by hydrodynamic tail-vein injection (20 mug/mouse). pTG7101 (but not the other plasmids) results in therapeutic and stable concentration of hAAT in plasma. A dose-response study with this plasmid (0.3-320 mug/mouse) confirms that hAAT remains long-term stable in plasma, with therapeutic concentrations of hAAT (40.9 mg/ml). The parameters of the dose-response curve were: R:0.98, E-max 3449.0+/-279.7 mug/ml and EC50 1.2x10(12) plasmid-gene units. In addition, 4 months after transfection, the intrinsic efficacy of transgenic expression (amount of RNA/DNA) in mouse liver was 50-80% that normally expressed by the mouse gene. The important efficacy of nonviral genomic DNA opens a new avenue in the safety applications of human gene therapy.