Angiogenesis induced in muscle by a recombinant adenovirus expressing functional isoforms of basic fibroblast growth factor

The present work studies the effects of a replication-deficient adenovirus (Ad), Ad-RSVbFGF, bearing the human basic fibroblast growth factor (bFGF) cDNA, as a potential vector for therapeutic angiogenesis of ischemic diseases. The different isoforms of the protein were expressed from the viral vector in various cell types and, although the cytoplasmic isoform does not possess a signal peptide, we observed its release from a muscle cell line. The proteins were fully functional when tested in a long-term survival assay of quiescent fibroblasts. After endothelial cell infection with Ad-RSVbFGF, we observed an 80&percnt increase in the mean length of the capillary-like tubes that differentiated in a three-dimensional model of angiogenesis. We evaluated angiogenesis directly in mice 14 days after subcutaneous injection of Matrigel plugs containing Ad-RSVbFGF. A marked neovascularization was observed in the Matrigel plugs and in the surrounding tissues. Finally, the recombinant virus was injected into the hindlimb muscles of mdx mice. A 2.5-fold increase in bFGF content of the muscle was observed 6 days after injection, without any significant variations detected in the animal sera. Immunohistological detection showed an increased number of large-caliber vessels in the treated muscles as compared with control muscles. These results demonstrate that Ad-mediated transfer of the human bFGF gene can induce angiogenesis in muscle, making this tissue a potential target for the treatment of ischemic diseases.