In vivo study of angiogenic plasmid preparations--the bicistronic plasmid as a new type of drug for vascular diseases.

Angiogenic gene therapy is thought to be a new method for the treatment for vascular diseases. Plasmid preparations encoding angiogenic factors like a vascular endothelial growth factor (VEGF) or a fibroblast growth factor (FGF) effectively stimulate the formation of new vessels. The first clinical trials with novel angiogenic drugs--genetic preparations have already been reported. Nevertheless, gene transfer and expression efficiency still require a lot of experimental work. Here, three different angiogenic preparations were studied. We used monocistronic vectors encoding VEGF165 or FGF-2 and bicistronic construct expressing both of them. The angiogenic potency of the plasmids was evaluated by in vivo angiogenesis tests. We also tested the plasmid DNA maintenance in mouse tissue as well as the transcriptional activity of the angiogenic preparations. We saw that all plasmids effectively stimulate the formation of new vessels in in vivo conditions up to 20 days. The most powerfull angiogenic potency was demonstrated by the bicistronic vector. It was shown that after 3, 13, 21, 31 and 41 days post-transfection the plasmid DNA still persisted in tissue, more or less on the same level but the mRNA transcripts after 13 days slowly decreased. This work confirmed effectiveness of gene therapy, and gave new information about angiogenic plasmid preparations useful for practical applications.