Therapeutic angiogenesis: a fantastic new adventure.

A significant proportion of patients with coronary artery disease have symptoms refractory to medical treatment, yet are unsuitable for conventional revascularization techniques, like percutaneous coronary intervention and coronary artery bypass surgery. Such patients are potential candidates for alternative forms of coronary revascularization, like therapeutic angiogenesis. This strategy is designed to promote the development of supplemental collateral blood vessels that will act as endogenous bypass conduits. Two major avenues for achieving therapeutic angiogenesis are currently under intense investigation: gene therapy (the introduction of new genetic material into somatic cells to synthesize proteins that are missing, defective, or desired for specific therapeutic purposes) and protein-based therapy (administration of the growth factors, instead of the genes encoding for the growth factors responsible for angiogenesis). This article provides a concise review of the "components" of gene and protein-based therapy, namely, the growth factors, the vector (for gene therapy), the route of delivery, the therapeutic target, the desired therapeutic effect, and quantifiable clinical end points for trials of angiogenesis. Based on preliminary studies, the authors believe that therapeutic angiogenesis represents a promising novel therapy for treatment of the ischemic heart. In the future, angiogenesis will likely be offered as an adjunct to conventional revascularization strategies in subsets of patients who are only "suboptimally" revascularized with conventional techniques, and might evolve into a stand-alone treatment for some patients with nonrevascularizable disease.