The RNIB likens sight loss to bereavement, with people experiencing long-lasting mental health ramifications as well as the physical sight loss itself. The wet form of AMD, present in about 10-15% of cases, causes permanent sight loss and very immediate central vision loss.
The prognosis for wet AMD is poor and conventional treatments very invasive, but advancements in stem cell therapy are giving patients new hope.
The London Project to Cure Blindness
In September 2015 a UK patient with advanced wet AMD was the first to receive a new embryonic stem cell treatment to restore her sight. Moorfields Eye Hospital conducted the treatment, and will also treat another 10 patients in the same way over an 18-month period.
It is a small trial used to investigate the efficacy and safety of transplanting eye cells from stem cells. The cells are used to replace damaged and diseased cells at the back of the eye, using a patch inserted behind the retina during an operation said to be as straightforward as cataract surgery.
At the moment the primary aim is to support undamaged cells, so they are not affected by the ‘toxic environment’ that AMD creates, restoring vision is a secondary aim, but still important too. The team have specifically chosen patients with a severe level of sight loss, to see just how much of an affect the treatment has on sight levels. The team hope a similar treatment could be used to treat other eye conditions such as Stargardt’s disease in the future
News was expected by December on the level of sight restored, but we are yet to hear from the project as yet.
Transplants and drug discovery
The eye is a good target for stem cell treatment, as it is relatively self-contained so the cells aren’t able to migrate to other parts of the body as easily. Comparisons are also easier to make, between a treated and untreated eye.
Stem cell research is helping increase medicine’s understanding of the retina and how it functions with different cells. The research shows promise in transplants of both rods and cones, and supporting RPE cells.
Research into stem cell treatment has increased our understanding of how RPE cells behave, and in turn how AMD progresses. Replacing rods and cones is tricky because they need to establish connections with nerve fibres, but this is not the case with RPE cells. RPE cells only need to integrate with existing retinal cells, not nerve fibers, so new RPE cells could replace diseased ones to support the eye. RPE cell transplants show promise for improving central vision and slowing AMD progression if the new RPE cells are transplanted before rods and cones have been lost.
Future treatment of AMD
The current treatments seek to support undamaged cells and to slow progressing, but the eventual aim is to replace the RPE layer. Doing this would halt AMD and maybe even reverse it.
The current challenge lies in growing cells at the right stage, known as optimal maturation, the more mature the cells are the less likely they are generate too many RPE cells. Cells transplanted at a too early stage could also migrate to other parts of the body more easily.
The methods of treatment are also still being developed, with the first treatment by the London Project to Cure Blindness being a patch of RPE cells. Another option is a suspension of cells injected under the retina, these cells are grown in a lab and then placed in a harmless fluid to be injected. The patch treatment shows the most stability but will either treatment allow RPE cells to integrate with the patient’s own cells?
Stem cell treatment for eyes is progressing fast, and there are many researchers working on improving methods, so we will see more news in the future. The key goal is to ensure RPE cells integrate with the patient’s own cells – this will allow rods and cones to be supported and for clinicians to treat specific eye conditions.
Read more about the London Project to Cure Blindness and stem cell therapy. For more information about AMD screening, symptoms and treatment, download our free whitepaper.