ApoE expression in C57BL/6 mice treated with liposomal formulations containing plasmid ApoE2 after 5 days of liposome administration. ApoE levels were quantified in different organs (brain, liver, kidneys, heart, lungs, spleen and blood) harvested from mice treated with plasmid ApoE2, Plain-liposome and Tf-Pen-liposomes containing chitosan-pApoE2 complexes (1 mg pDNA/kg body weight). Seven mice were used per group. Data are expressed as mean ± SD. Statistically significant differences (p < 0.05) are shown as (*).