Safety of liver surface instillation of plasmid DNA in normal and carbon tetrachloride-induced hepatitis mice.

PURPOSE We previously demonstrated liver- and lobe-selective gene transfer following instillation of plasmid DNA (pDNA) onto the liver surface in mice. Safety concerns must be resolved prior to future clinical use. Thus, we investigated safety of liver surface instillation of pDNA in normal and hepatitis mice. METHODS pDNA was instilled onto the liver surface in normal and carbon tetrachloride-induced hepatitis mice. Gene expression (luciferase activity) and serum transaminase activities were measured at appropriate time points. RESULTS Transfection efficiency and target site selectivity were almost the same between the instillation of pDNA using a micropipette and a catheter. Serum transaminase activities 6 h after instillation of pDNA or a vehicle treatment using a micropipette were significantly higher than the no treatment mice, whereas instillation using a catheter did not raise serum transaminase activities throughout the tested time points, suggesting the safety of instillation using a catheter. This safety was also confirmed in hepatitis mice. A dose escalation study verified that liver surface instillation using a catheter did not raise serum transaminase at high doses with saturation of gene expression not only in normal mice, but also in hepatitis mice, supporting the safety of this method. CONCLUSIONS We demonstrated that liver surface instillation of pDNA using a catheter did not raise serum transaminase activities. Information in this study will be useful for future clinical use of liver surface instillation of pDNA using a catheter.