Scientists have developed the first possible therapy for the most common cause of blindness in over-50s — dry age-related macular degeneration (AMD).
The condition causes blind spots and blurry vision and can lead to sight loss.
In a new study in Israel, patients are being given injections of special cells to replace those killed off in the condition; the hope is that this will stop the disease progressing.
If the study is successful, larger trials which will make the treatment available for use will be starting later this year.
Scientists have developed the first possible therapy for the most common cause of blindness in over-50s — dry age-related macular degeneration (AMD)
AMD is estimated to affect more than half a million people in the UK. There are two forms, wet and dry.
Both types occur when cells in the macula, the light-sensitive area at the back of the eye, become damaged, leading to deteriorating vision.
Wet AMD develops when abnormal blood vessels form underneath the macula and cause swelling and bleeding, which very quickly results in irreparable damage.
Untreated, it can cause blindness within three months. It is treated with injections of chemicals known as anti-vascular endothelial growth factor, which stop the development of these blood vessels.
Dry AMD, which accounts for 90 per cent of cases, occurs when the cells of the macula become damaged by a build-up of deposits called drusen.
Vision deteriorates gradually over many years but there is currently no treatment for it.
The slow progression and complex mechanisms involved in dry AMD have meant it has been difficult to develop a treatment.
Exactly how drusen deposits form is unclear, but they are thought to be waste products from neighbouring cells and tissues of the retina.
The treatment involves injecting a solution which contains up to 500,000 of RPE cells made in a lab into the back of the patient’s eyes, just underneath the retina
This is a normal process in people without dry AMD too, but usually the deposits are cleared up by retinal pigment epithelial (RPE) cells found next to the macula.
The theory is that in dry AMD, these retinal cells die off first, meaning the clear-up mechanism is slow or stops, resulting in excess deposits.
BREAKTHROUGH IN DRUG RESEARCH COULD HELP CURE BLINDING DISEASES
Scientists have found another possible target for future drugs to treat blinding diseases such as AMD and retinitis pigmentosa, an inherited condition which causes damage to photoreceptors.
Scientists have found another possible target for future drugs to treat blinding diseases such as AMD and retinitis pigmentosa
In experiments on mice, researchers at Washington University in St Louis identified a molecule called NAD which is lowered in these conditions and leads to the death of photoreceptors.
When mice were injected with a chemical that boosts levels of NAD, cell degeneration ceased and vision was restored, according to the journal Cell Reports.
The new approach, developed by Israeli company Cell Cure Neurosciences, is based on injections of RPE cells made in a lab.
The cells are derived from donated embryos and are treated with chemicals to help them turn into adult RPE cells.
The treatment involves injecting a solution which contains up to 500,000 of these retinal cells into the back of the patient’s eyes, just underneath the retina.
In a new trial at three hospitals across Israel, 15 patients with dry AMD will receive one injection — researchers will then monitor the progression of the disease for a year, using a battery of vision tests at set intervals.
Studies in mice have shown that the injection treatment, called OpRegen, is safe and effective, and that it preserves vision and structure of the retina.
When the cells were injected they formed a single-layer structure similar to the natural layer of cells, and survived for the lifetime of the mice, according to the journal Cell Stem Cell in 2009.
The proven ability of the injected cells to behave like this is critical to the success of the therapy in humans, the researchers said.