An animal study in the journal Nature Biotechnology showed the part of the eye which actually detects light can be repaired using stem cells.
The team at Moorfields Eye Hospital and University College London say human trials are now, for the first time, a realistic prospect. Experts described it as a “significant breakthrough” and “huge leap” forward.
Photoreceptors are the cells in the retina which react to light and convert it into an electrical signal which can be sent to the brain. However, these cells can die off in some causes of blindness such as Stargardt’s disease and age-related macular degeneration. There are already trials in people to use stem cells to replace the “support” cells in the eye which keep the photoreceptors alive.
Now the London-based team have shown it is possible to replace the light-sensing cells themselves, raising the prospect of reversing blindness. They have used a new technique for building retinas in the laboratory. It was used to collect thousands of stem cells, which were primed to transform into photoreceptors, and injected them into the eyes of blind mice. The study showed that these cells could hook up with the existing architecture of the eye and begin to function.
However, the effectiveness is still low. Only about 1,000 cells out of a transplant of 200,000 actually hooked up with the rest of the eye. Lead researcher Prof Robin Ali told the BBC News website: “This is a real proof of concept that photoreceptors can be transplanted from an embryonic stem cells source and it give us a route map to now do this in humans.
“That’s why we’re so excited, five years is a now a realistic aim for starting a clinical trial.”
Rods, blue, and cones, blue-green, detect light and create electrical signals which are sent to the brain.
The eye is one of the most advanced fields for stem cell research. It is relatively simple as the light sensing cells only have to pass their electrical message on to one more cell in order to get their message to the brain, unlike an attempt to reverse dementia which would require cells to hook up with far more cells all across the brain.
The immune system is also very weak in the eye so there is a low chance of the transplant being rejected. A few cells can also make a big difference in the eye. Tens of thousands of stem cells in the eye could improve vision, but that number of stem cells would not regenerate a much larger organ such as a failing liver. …
The above was from 2013. Did they start human trials? Yes.
29 Sep 2015
The first patient has been treated with a new stem-cell-derived treatment for ‘wet’ age-related macular degeneration (AMD) as part of a pioneering clinical trial in London.
Using technology developed with MRC funding, the trial will test if it is safe and effective to transplant a type of eye cell called retinal pigment epithelial (RPE) cells, grown from stem cells in the lab, to restore sight in people with severe visual loss from wet AMD. The cells are used to replace diseased ones at the back of the eye using a specially engineered patch. The patch is inserted behind the retina in a surgical operation which lasts one to two hours.
A woman was successfully treated last month and to date there have been no complications. The research team hope to assess the extent to which she has recovered her vision by early December.
Professor Pete Coffey of the University College London Institute of Ophthalmology, who is co-leading the research, said: “We are tremendously pleased to have reached this stage in the research for a new therapeutic approach. Although we recognise this clinical trial focuses on a small group of AMD patients who have experienced sudden severe visual loss, we hope that many patients may benefit in the future.”
The trial will recruit another nine patients over 18 months, each of whom will be followed for a year to assess the safety and stability of the cells and whether there is an effect in restoring vision.
In 2018, we can ask, did it work? Yes. Sight has been somewhat restored with this technique, but it only works in some patients.
Two patients suffering the most common form of sight loss in Britain can read again after a groundbreaking stem cell patch was transplanted into their eyes.
An 86-year-old man, and a woman in her 60s, had both been diagnosed with wet age-related macular degeneration (AMD), a condition which causes loss of central vision.
AMD affects more than 600,000 people in Britain and occurs when the specialised light-sensitive cells at the very centre of the retina – a region called the macular – become damaged.
Currently the only treatments available are injections into the eye, or laser surgery, which both slow the growth of blood vessels which harm the macular. However they only partially restores sight and do not work for everyone.
As they refine it, this should be much bigger news.