Based on a study on angina patients, it was found that transferring growth factor genes into the heart is safe and improves exercise tolerance. In angina, the blood supply to the heart is limited, leading to pain on exertion. Initially the body tries to compensate by growing new blood vessels to bypass the restricted area. But, for some unknown reason, this process, known as angiogenesis, soon switches off again.
Researchers at the Hopkins University, have been developing a form of gene therapy to try to restart angiogenesis. They injected a gene for a growth factor that stimulates blood vessel generation into 70 men and women with angina. A further 20 people acted as controls.
The gene therapy proved safe - the gene itself, introduced via a virus 'carrier', stayed in heart tissue. What's more, there were small but significant increases in exercise tolerance - as measured by a treadmill test - in those receiving the gene therapy. This was just a small study which needs to be repeated in a larger group, but the results look highly encouraging.