Gene therapy for failing hearts?

Gene therapy could soon be used to treat heart failure patients, say US researchers, following their success with human heart cells growing in the laboratory. Scientists at Jefferson Medical College and Duke University used gene therapy to repair damaged heart cells, helping them to beat normally again. The team, who published their findings in the journal Circulation, say that the study is 'the last proof of concept' for such an approach, and that work in animals is now progressing.

Congestive heart failure occurs when the heart is not strong enough to pump blood efficiently around the body, so fluid collects in the lungs and body tissues. The condition is not curable, but treatment can help prevent it worsening. In the new study, team leader Walter Koch and colleagues used a virus to deliver a therapeutic gene into heart cells taken from heart failure patients. The gene makes a small protein called beta-ARKct, which blocks the action of an enzyme called beta-ARK1 (beta-adrenergic kinase). It seems that high levels of beta-ARK1 in failing hearts contribute to its lack of strength, which the researchers hoped to restore.

The scientists found that by blocking the excess beta-ARK1, they could improve the performance of the heart cells, allowing them to beat at normal strength again. They think the treatment works by increasing the amount of certain 'receptor' molecules on the heart cell surface, which, in the body, cause the heart to beat faster in response to stress or exercise. Koch said: 'This is the first work in actual human hearts to show the efficacy of beta-ARKct as a potential therapy and more importantly, proves that the enzyme beta-ARK1 is a target for heart failure treatment'.

Professor Sir George Charles, medical director of the British Heart Foundation cautioned that although interesting, the work was done in isolated cells, and not in heart failure patients. 'The implications for treatment of patients are uncertain, because gene therapy has often produced only short term benefits in living animals and humans', he told BBC News Online. Professor Eric Alton, of Imperial College London agreed, saying: 'The key will be to see if these interesting laboratory studies can be translated into benefit in living human patients'.