Angiogenesis is a natural process in the body that involves the growth of new blood vessels.  It can occur during coronary artery disease, peripheral artery disease and stroke when there's insufficient blood supply and oxygen to the tissues, a condition known as ischemia.  The body's first response to less blood flow to the heart is to grow tiny new "collateral" vessels to help blood flow around the blockage.  For unknown reasons, the process eventually switches off.  Some proteins in the body can help trigger new blood vessel growth and so increase the oxygen supply to the ischemic tissue.  Such angiogenic proteins include the endothelial growth factor, vascular endothelial growth factor (VEGF) and fibroblast growth factor (FGF).

Scientists are using gene therapy to copy this natural process by delivering angiogenic genes to ischemic tissue.  For example, let's say the goal is to create or improve blood flow in peripheral (leg) or coronary (heart) arteries damaged by vascular disease.  Then, the ability to "turn on" the angiogenesis gene could be a potentially powerful way to "grow" new blood vessels.

Several scientific studies involving gene therapy trials for cardiovascular disease in humans are under way and look very promising.  However, gene therapy still needs many improvements before it becomes routine treatment for cardiovascular disease in the clinic.