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) c DNA, as a potential vector for therapeutic angiogenesis of ischemic disease s. The different isoforms of the protein were expressed from the viral vect or in various cell types and, although the cytoplasmic isoform does not pos sess 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 o f quiescent fibroblasts. After endothelial cell infection with Ad-RSVbFGF, we observed an 80% increase in the mean length of the capillary-like tubes that differentiated in a three-dimensional model of angiogenesis. We evalua ted angiogenesis directly in mice 14 days after subcutaneous injection of M atrigel plugs containing Ad-RSVbFGF. A marked neovascularization was observ ed in the Matrigel plugs and in the surrounding: tissues. Finally, the reco mbinant virus was injected into the hindlimb muscles of mdx mice. A 2.5-fol d increase in bFGF content of the muscle was observed 6 days after injectio n, without any significant variations detected in the animal sera. Immunohi stological detection showed an increased, number of large-caliber vessels i n the treated muscles as compared with control muscles. These results demon strate that Ad-mediated transfer of the human bFGF gene can induce angiogen esis in muscle, making this tissue a potential target for;the treatment of ischemic diseases.