Britain trials embryonic stem cells as treatment for blindness

UK scientists have been granted approval to begin the first clinical trial using embryonic stem cells (ES cells) in Europe, which they hope could lead to an effective treatment for a degenerative eye disease causing blindness. The team at Moorfield's Eye Hospital in London will inject stem cells into the eye's of patients with Stargardt's macular dystrophy, a genetic condition that causes blindness, in order to test the safety of the stem cell therapy.

The trial was approved by the UK’s Medicines and Healthcare products Regulatory Agency (MHRA) and the researchers will now start the process of recruiting 12 patients with advanced Stargardt's macular dystrophy to participate in the study. The patients will receive an injection of between 50,000 and 200,000 cells behind the retina.

The researchers hope the treatment will halt or even reverse the progression of the disease. 'It's more realistic that it will protect against further sight loss', said Professor James Bainbridge, a retinal surgeon at Moorfield's Eye Hospital who is leading the trial. He added that if the trial is a success, the treatment could become a routine procedure within five years.

'There is a real potential that people with blinding disorders of the retina, including Stargardt's disease and age-related macular degeneration, might benefit in the future from transplantation of retinal cells', Professor Bainbridge said.

Stargardt's macular dystrophy is a genetic condition that causes degeneration of the light sensitive photoreceptor cells in the eye's retina, and of the retinal pigment epithelial (RPE) cells that lie beneath and support the retina. The disease affects around 5,000 people in Britain, and is normally diagnosed in patients between 10 and 20 years of age.

The study will use human ES cells to generate healthy RPE cells in the laboratory for injecting into the eye. The technology was developed by the US biotechnology company Advanced Cell Technology (ACT), which is involved in the UK clinical trial and conducting a similar trial in the United States.

Chris Mason, Professor of Regenerative Medicine at University College London, said: 'ACT, a leading US company, by undertaking this important clinical trial in London, endorses the UK's position as world leaders in stem cell therapies. This is the first application of an embryonic stem cell-based therapy into the eye'.

The potential of ES cells to help regenerate damaged tissue has long been recognised, and has been a major goal of regenerative medicine since a method to grow these cells in the laboratory was established more than a decade ago. But the use of ES cells raises ethical questions because their creation involves the destruction of human embryos. The UK trial is one of the first to translate ES research into the clinical setting.

Professor Colin Blakemore from the University of Oxford said: 'The ultimate justification for all of the work that has been done is that it will lead to a great advance in medical treatment. It's good to see this progress towards such applications'.

But he added: 'It is very important that expectations are not unrealistically raised, and that people distinguish between legitimate trials such as this one and the many bogus and potentially dangerous treatments that you can find on the internet and abroad'.