Biodistribution and Gene Expression of Lipid/Plasmid Complexes after Systemic Administration

Abstract

The objectives of this study were to investigate the influence of physicochemical properties of lipid/plasmid complexes on in vivo gene transfer and biodistribution characteristics. Formulations based on 1,2-di-O-octadecenyl-3-trimethylammonium propane (DOTMA) and novel biodegradable cationic lipids, such as ethyl dioleoyl phosphatidylcholine (EDOPC), ethyl palmitoyl myristyl phosphatidylcholine (EPMPC), myristyl myristoyl carnitine ester (MMCE), and oleyl oleoyl L-carnitine ester (DOLCE), were assessed for gene expression after tail vein injection of lipid/plasmid complexes in mice. Gene expression was influenced by cationic lipid structure, cationic lipid-to-colipid molar ratios, plasmid-to-lipid charge ratios, and precondensation liposome size. Detectable levels of human growth hormone (hGH) in serum, human factor IX (hFIX) in plasma, and chloramphenicol acetyltransferase (CAT) in the lung and liver were observed with positively charged lipid/plasmid complexes prepared from 400-nm extruded liposomes with a cationic lipid-to-colipid ratio of 4:1 (mol/mol). Intravenous administration of lipid/CAT plasmid complexes resulted in distribution of plasmid DNA mainly to the lung at 15 min after injection. Plasmid DNA accumulation in the liver increased with time up to 24 hr postinjection. There was a 10-fold decrease in the amount of plasmid DNA in the lung at 15 min after injection, when the lipid/plasmid complex charge ratio was decreased from 3:1 to 0.5:1 (+/-). Bright fluorescent aggregates were evident in in vivo-transfected lung with the positively charged pCMV-CAT/DOLCE:dioleyl phosphatidylethanolamine (DOPE) (1:1, mol/mol) complexes, while more discrete punctate fluorescence was observed with a 4:1 molar ratio of cationic lipid:colipid formulations. Preinjection of polyanions such as plasmid, dextran sulfate, polycytidic acid, and polyinosinic acid decreased hGH expression, whereas the preinjection of both positively charged and neutral liposomes had no effect on hGH serum levels. Of the cationic lipids tested, DOLCE was found to be the most effective potentially biodegradable cationic lipid. A correlation between gene expression and cationic lipid:colipid ratios and lipid-to-plasmid charge ratio was also observed for DOTMA- and DOLCE-based formulations.

The role of tissue macrophages in the induction of proinflammatory cytokine production following intravenous injection of lipoplexes

“…administration, as reported by other groups ( Figure 1a). 25,26 The lung accumulation of the lipoplex gradually decreased in both groups, however, a significantly higher amount of lipoplex was left in the lung of GdCl 3 -pretreated mice compared with saline-pretreated mice 1 h after injection. In addition, accumulation of lipoplex in the liver gradually increased in both groups (Figure 1b).…”

Dextran–spermine polycation: an efficient nonviral vector for in vitro and in vivo gene transfection

“…The particle size, charge, and the surface characteristics of the complex have a strong influence on the plasmid DNA body distribution and transfection efficiency. 24,26,[30][31][32][33] In recent publications, 34,35 we reported on a new class of biodegradable polycations capable of complexing and transfecting various genes to many cell lines in relatively high yields. More than 300 different polycations were prepared starting from various natural polysaccharides and oligoamines having two to four amino groups.…”

Cationic lipid-based delivery system for systemic cancer gene therapy

“…5,9 The purity of the plasmid preparations was determined by 1% agarose gel electrophoresis followed by SYBR Green (Molecular Probes, Eugene, Ore) staining, and the pDNA plasmid DNA (pDNA) concentration was measured by ultraviolet absorption at 260 nm. The percentage of supercoiled pDNA was in the range of 80 -95%.…”