GENE THERAPY OF CORONARY ARTERY DISEASE

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Our studies are aimed at evaluating whether gene therapy with replication- deficient, recombinant adenovirus vectors can be used to prevent and treat restenosis after angioplasty and to induce angiogenesis to restore blood supply to ischemic tissues. For the studies on angiogenesis, we have constructed adenoviral vectors which carry the cDNA for the following angiogenic growth factors: (1) Vascular endothelial growth factor (VEGF), (2) Acidic fibroblast growth factor (aFGF), (3) A recombinant form of aFGF which modified by the addition of the secretory signal sequence from FGF-4 (sp-aFGF), (4) Basic FGF(bFGF), (5) A recombinant form of bFGF which was modified by the addition of the secretory signal sequence form FGF-4, and (6) platelet-derived endothelial cell growth factor (PD-ECGF). For the studies on restenosis after angioplasty, we plan to use adenoviral vectors which carry the cDNA for the following proteins: 1) VEGF and PD-ECGF. These viral vectors may enhance reendoth elialization at the site of endovascular injury and decrease the severity of intimal hyperplasia by this mechanism. (2) p53, apoptosis. The following studies have been implemented as part of this study. Studies in vitro have shown that the above adenovirus vectors make functional proteins and modulate cell growth. In experiments in vivo we have shown that the adenovirus vectors which carry the cDNA either for aFGF for the secreted form of aFGF induce angiogenesis in vivo when coinjected with Matrigel, subcutaneously in mice. Since persistent expression of growth factors may have a tumorigenic potential we have examined the biosafety of the adenovirus vectors which carry the cDNA for acidic FGF and for the secreted form of acidic FGF. Our in vivo studies with nude mice show that these vectors do not cause tumor formation. We examined the safety and efficacy of gene transfer into minipig heart either with the intramyocardial (IM) or intracoronary (IC) injection of adCMV.NLSbeta-gal. IM injection was more effective than IC infusion in targeting cell transduction to a well-defined area of myocardium. Followin IM injection exogenous gene expression peaked at 2-4 days and returned to control value within one month. No minipigs died and by epicardial echocardiography there was no evidence of either segmental or global left ventricular dysfunction. Thus, Ad vectors appear safe and effective for gene transfer into the myocardium of large mammals. 5) Experiments on restenosis have been aimed at developing a rat model of intimal hyperplasia after carotid artery injury and minipig model of coronary intimal hyperplasia.