British scientists’ amazing ‘stem cell cure’ for blindness

VICTIMS of a devastating form of blindness have been given hope by a new stem cell treatment that rejuvenates the eyes.

There is no cure for retinitis pigmentosa (RP), an inherited condition that slowly constricts vision, but a British firm has reported early success with a revolutionary procedure that helps repair a damaged retina.

The treatment involves growing billions of ‘progenitor’ stem cells in a laboratory. These have the ability to transform themselves into other types of cell depending on where they are placed in the body.

A million stem cells are injected into the back of the patient’s eyeball. Once there, they transform themselves into new lightsensitive cells called rods and cones which replace those lost prematurely to genetic flaws.

Tests on three patients – two men and a woman – who were legally blind produced ‘exciting’ results, according to Olav Hellebo, chief executive of UK biotech firm ReNeuron.

Before the procedure, the three could read only the largest group of letters on a special eye test chart. But 18 days after being injected with the cells, their sight had improved so that they could read three letter sizes smaller.

One patient achieved sufficient progress to no longer be classified as legally blind and another told her doctor that she was able to see the food on her plate for the first time in years.

Mr Hellebo said: ‘We are very excited. We have to bear in mind all the caveats – that these are results in only three patients and it is early days – but the reaction from ophthalmologists has been very encouraging.’

The patients are American but the development of the technology has been led by experts at ReNeuron in Bridgend, Wales.

Nine more patients have been enrolled to test the procedure.

Mr Hellebo said the woman, who had been ‘sceptical’ before the procedure, went from being able to see just nine letters on the eye test chart to 29. People are considered legally blind if they can read fewer than 36 letters on the 100-letter chart.

The two men improved from nine to 24 letters and from 31 to 45. RP, which affects up to 25,000 people in Britain, is caused by about 100 inherited genetic defects, sometimes alone and sometimes in combination.

Loss of vision can begin in childhood, adolescence or adulthood and starts with deteriorating night vision and peripheral vision which gradually narrows so only hazy tunnel vision eventually remains. Total blindness usually ensues.

Mr Hellebo’s company will present further information about the trial at the annual Retinal Cell and Gene Therapy Innovation Summit in Vancouver, Canada, this month.

He said: ‘It’s a horrible diagnosis because you know where it’s headed and there’s nothing you can do about it.’

Tina Houlihan, of the Retina UK charity which supports people with inherited sight loss, said: ‘These early results are encouraging and will provide hope to those with retinitis pigmentosa.

‘However, while the trial is at this very early stage, with only a very small number of patients involved, we are cautious in our optimism.’