StemCell Therapy

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The revolutionary therapy involves placing a gene into the eye to combat wet age related macular degeneration (AMD).

It could lead to reducing patients' visits to surgeries - and preserving their vision in the long term.

About 600,000 Britons suffer from AMD which comes in two forms, wet and dry. The former is rarer, but much more serious, damaging sight in a much shorter time scale.

The disease is marked by growth of abnormal blood vessels that leak fluid into the centre of the retina, called the macula, which we use for reading, driving and recognising faces.

The therapeuticgene is carried into the eye by a harmless virus similar to the common cold, penetrating retinal cells and turning them into factories producing proteins called sFLT01.

These attack the molecule VEGF (vascular endothelial growth factor) that boost the growth of the abnormal blood vessels that trigger wet AMD.

Professor Peter Campochiaro, of Johns Hopkins University, Baltimore, said: This preliminary study is a small but promising step towards a new approach that will not only reduce doctor visits and the anxiety and discomfort associated with repeated injections in the eye, but may improve long-term outcomes because prolonged suppression of VEGF is needed to preserve vision, and that is difficult to achieve with repeated injections because life often gets in the way.

The study of 19 men and women with advanced wet AMD who were 50 years or older found the treatment was safe and may be effective for saving vision.

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Even at the highest dose, the treatment was quite safe

Professor Peter Campochiaro

It was described in The Lancet as an exciting new approach. Current treatments require injections of proteins directly into the eye that inactivate VEGF, reducing fluid in the macula and improving vision.

But they exit the eye over the course of a month, so patients usually need to return to the clinic for more injections every six to eight weeks in order to stave off vision loss.

Eye specialists say the burden and discomfort is responsible for many patients not getting injections as frequently as they need, causing vision loss.

Viruses naturally penetrate cells and leave behind genetic material, so the researchers designed their's to target retinal cells and provide them with a gene that produces sFLT01.

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They become factories that produce the therapeutic protein - potentially eliminating the need to repeatedly inject it.

The participants were divided into five different groups that received increasing doses. They were examined for signs of adverse reactions for at least four weeks before administering a higher amount.

After the virus deposited the gene, the cells began secreting sFLT01 which bound to VEGF and prevented it from stimulating leakage and growth of abnormal blood vessels.

The goal is for the retinal cells infected by the virus to produce enough sFLT01 to stop permanently the progression of AMD.

After monitoring the first three groups and finding no dose-limiting toxicity, the researchers administered the maximum dose to a group of ten participants and observed no serious side effects.

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Prof Campochiaro said: Even at the highest dose, the treatment was quite safe. We found there were almost no adverse reactions in our patients.

For safety and ethical reasons, the study group was composed of people for whom standard approved treatments were highly unlikely to regain vision, meaning in part that only 11 of the 19 had the potential for fluid reduction

Of those eleven patients, four showed dramatic improvements. The amount of fluid in their eyes dropped from severe to almost nothing, just like what is observed with optimal standard treatment.

In addition, two other participants showed a partial reduction in the amount of fluid in their eyes, added Prof Campochiaro.

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Five participants showed no reduction in fluid levels, all of whom had pre-existing antibodies to the common cold virus AV2 (adeno-associated virus 2).

From that result, the researchers conclude even if further studies affirm the safety and value of their gene therapy, it may have limitations for broad use.

An estimated six in ten people have been infected with adeno-associated virus, the family of viruses that AAV2 belongs to, and have built an immunity to it.

In these patients, it is believed the immune system destroyed the virus before it could insert the therapeutic gene.

Explained Prof Campochiaro: The numbers are small and simply show a correlation, so we don't know if serum antibodies are definitely an impediment, but more work is needed to determine this.

AMD causes fading vision in the middle or later years of life. It is most common after 60 but can happen earlier. It is also the leading cause of vision loss in the developed world.

Dame Judi Dench revealed in 2012 that she was suffering from AMD and was struggling to read film scripts or recognise faces.

Continued here:
Blind treatment: New therapy could stop THOUSANDS from losing their sight - Express.co.uk

This entry was posted on May 17, 2017 at 12:50 am and is filed under Eye Sight & Vision. You can follow any responses to this entry through the RSS 2.0 feed. Both comments and pings are currently closed. |