Radical gene therapy that restores sight in mice and dogs could be used on humans: Implant in your eye could banish reading glasses forever

 

 

 

 

Radical gene therapy that restores sight in mice and dogs could be used on humans Treatment allows scientists to remodel eye cells into light receptors It uses a gene that alters eye cells and an injected chemical 'photoswitch' The photoswitch works with the gene to turn light sensitivity on in cell Blind rescue dogs could see flashing lights after treatment, study says Blind mice became as good at navigating a water maze as normal mice The treatment could be used to help people with retinitis pigmentosa - an inherited condition resulting in progressive loss of sight A radical form of gene therapy that remodels eye cells into light receptors has allowed scientists to partially restore the sight of animals with inherited blindness. Scientists say the same technique could one day be used to treat people with retinitis pigmentosa - an inherited condition resulting in progressive loss of sight. In early tests on blind rescue dogs with a similar condition, showed they could restore sufficient light sensitivity for the animals to distinguish between flashing and non-flashing lights. +3 In normal mice (left), stimulating the retina produced a variety of responses, as shown by the colours. A similar response was achieved using the radical new therapy in blind mice - as shown in the colourful centre square. The right image reveals the blind mice who had the therapy in different retinal ganglion cells. The results in these types of cells were less dramatic Blind mice given the same treatment became as good at navigating a water maze as normal mice. Two components of the 'hybrid' treatment involve a gene that alters non-light sensitive cells and an injected chemical 'photoswitch'. 'The dog has a retina very similar to ours, much more so than mice, so when you want to bring a visual therapy to the clinic, you want to first show that it works in a large animal model of the disease,' said Professor Ehud Isacoff, lead research from the University of California, Berkeley. 'We've now showed that we can deliver the photoswitch and restore light response to the blind retina in the dog as well as in the mouse, and that the treatment has the same sensitivity and speed of response. We can reanimate the dog retina.' The therapy is one of a number of potential treatments for blindness at early stages of development, two of which yielded exciting trial results this year. +3 Benjamin Gaub (left) and John Flannery observing a mouse in a water maze, in which the mouse swims to a platform designated by bright flashing lights In October scientists from the Massachusetts –based company Ocata Therapeutics, formerly known as Advanced Cell Technology, showed that stem cell-derived retinal cells could safely be implanted into patients and improve vision in some cases. Earlier this year scientists at Oxford University hailed trial results from a genetic therapy for choroideremia, a rare inherited cause of blindness that affects one in 50,000 people. HOW WAS IT DONE? Two components of the 'hybrid' treatment involve a gene that alters non-light sensitive cells and an injected chemical 'photoswitch'. Retinitis pigmentosa involves the progressive loss of both kinds of photoreceptors in the retina – the rods and the cones. As well as rods and cones there are other cells in the retina – named the ganglion and the bipolar cells – that can remain undamaged. The new treatment uses a virus to insert a gene into normally these cells in the retina that gives them the potential to 'see'. The gene makes a protein that acts like a lock. When the right molecular key from the photoreceptor switch is slotted into the lock, light sensitivity is turned on. Inserting a missing gene called REP1 prevented progression towards blindness and led to dramatic improvements in sight for two men at an advanced stage of vision loss. The new treatment uses a virus to insert a gene into normally non-light sensitive cells in the retina that gives them the potential to 'see'. The gene makes a protein that acts like a lock. When the right molecular key from the photoreceptor switch is slotted into the lock, light sensitivity is turned on. At present a new injection of the photoswitch has to be made every week to maintain its effect, since the molecule is naturally removed after a period of time. Several of the dogs have been treated and are currently undergoing tests to determine what level of light sensitivity they now have. The dogs already had the genetic disease when they were rescued from breeders and recruited for the study. Co-author Dr William Beltran, from the University of Pennsylvania School of Veterinary Medicine in the US, said: 'Use of such a clinically relevant large animal model allows us to begin tackling the next challenges on the road to translating this novel therapeutic strategy to human patients.' The therapy is said to show promise because although diseases such as RP destroy the eye's photosensitive cells, other cells in the retina are often left intact and unharmed. +3 Scientists say the technique could one day be used to treat people with retinitis pigmentosa - an inherited condition resulting in progressive loss of sight They include bipolar and ganglion cells, which both transmit visual nerve signals but do not contain photoreceptors. In tests on mice, the gene was successfully inserted into almost every one of the rodent's million or so retinal ganglion cells. According to the researchers, this should be enough to restore useful vision. 'So far we can say that the treated mice can distinguish between steady light and flashing light,' said Prof Isacoff. 'Our next step is to figure out how good they are at telling images apart.' The scientists are also looking to see if the photoswitch can be used to activate other receptor types, including some that might allow perception of fainter light. RP affects at least two million around the world. An estimated one in 80 of the population carries one of the faulty genes that cause the disease.

Liquid solution allows researcher to see clearly in total darkness Solution uses Chlorin e6 (Ce6) insulin and saline to enable night vision A test subject was able to see in darkness 'for several hours' Ability wore off the following day, with 'no noticeable effects' after 20 days But researchers warn of a high risk of cellular toxicity as a result of the solution and said chemicals should be 'handled with caution’ A team of scientists claim it has found a way to inject people’s eyes with ‘night vision’. The research gave one volunteer the ability to see more than 164ft (50 metres) in almost total darkness for 'several hours'. By injecting his eyes with a liquid solution, he could spot people running among trees in dark conditions 100 per cent of the time, while others who hadn't been treated with the drops were successful in only a third of cases. +3 Californian researchers have developed a liquid that enables night vision. The solution combines Chlorin e6 (Ce6) with insulin and saline. A small amount of it was dripped it into a researcher's eyes. It briefly turns the eyes dark or black before it is absorbed, seen in this image of researcher Gabriel Licina The experiment was carried out by a group of so-called ‘biohackers’ in California called Science for the Masses. They used a solution of a substance called Chlorin e6 (Ce6), which is found in some deep-sea fish and has light-amplification properties, and is also been used in cancer treatment research. Combining Ce6 with insulin and saline, the team produced a solution that can increase vision in low light conditions. NIGHT VISION CONTACT LENSES In April, researchers revealed a super-thin infrared light sensor, which could become an invaluable tool for the soldiers of the future as researchers work to develop the advance into night vision contact lenses. Created by University of Michigan researchers Ted Norris and Zhaohui Zhong, the sensor uses an atom-thin material called graphene which could be layered onto contact lenses. Graphene takes infrared rays and translates them into electrical signals. The process is similar to the way silicon chip in a digital camera work with visible light, Wired reported. 'If we integrate it with a contact lens or other wearable electronics, it expands your vision,' Zhong said. 'It provides you another way of interacting with your environment.' They note in their paper, though, that ‘the high risk of cellular toxicity from outside contaminants being absorbed through the skin make this chemical something that should only be handled with caution.’ As a result it is not advisable for people to carry out the procedure themselves at home. Russell Peake, Eye Health Condition Manager at Boots Opticians, told MailOnline that people should not attempt to recreate the experiment. 'Unless a solution has been prescribed or recommended by an optometrist, GP or pharmacist, people should not be inserting anything into their eyes,' he warned. 'An invasive eye procedure should only ever be undertaken by a trained expert in a clinical environment, as wrong use could lead to disruption or damage of the eye’s surface or tears, potentially leading to vision loss. 'Whilst the idea of "night vision eye drops" may seem interesting, this appears to be an unlicensed and unproven solution that has no medical approval. 'We would strongly advise against anyone trying this at home as the risks could potentially be very damaging and would advise people speak to their local optician for further information or advice.' +3 The experiment was carried out by a group of so-called ‘biohackers’ in California called Science for the Masses. It is not advisable to try this at home. They used a solution containing Chlorin e6 (Ce6), found in some deep-sea fish and has light-amplification properties, and is also used in cancer treatment research In the team's experiment, the liquid was dripped onto the conjunctival sacs on the eye of Gabriel Licina, one of the researchers, which carried the solution to his retinas. ‘Ce6 solution was added to the conjunctival sac via micropippette at three doses of 50μl [microlitres] into each eye,’ the researchers wrote. The solution initially made his eyes turn black, before being absorbed in a few seconds and returning his eyes to their natural colour. 'To me, it was a quick, greenish-black blur across my vision, and then it dissolved into my eyes,' Mr Licina told Mic. However, to ‘reduce the potential for bright light exposure,’ the team covered his eyes in black contact lenses. Within an hour his vision had noticeably improved in low-light conditions. To test the effects, Mr Licina and four ‘control’ subjects who had not been given the solution were taken to a ‘darkened area’. +3 Within an hour, Mr Licina was able to see in darkness - for several hours. In experiments he could see three times better than 'normal' eyes. After testing, Mr Licina wore sunglasses while he slept, and his eyesight in the morning seemed to return to normal. Shown is a stock image of US soldiers in Iraq in 2003 They were then asked to identify symbols in the dark, either moving or still, and to spot individuals moving in a small grove of trees. ‘The Ce6 subject consistently recognised symbols that did not seem to be visible to the controls,’ the researchers wrote. And, in the second test: ‘The Ce6 subject identified the distant figures 100 per cent of the time, with the controls showing a 33 per cent identification rate.’ After testing, the team said that Mr Licina wore sunglasses while he slept, and his eyesight in the morning appeared to return to normal. ‘As of 20 days, there have been no noticeable effects,’ they said. While they note that more testing is needed, the initial results suggest that the technique can provide low light amplification in the human eye. ‘Further testing is need to confirm and measure the degree of improvement in health subjects,’ they concluded.   Tiny 'Raindrop' implant in your eye could banish reading glasses forever Procedure would help an ageing patient's ability to focus on close up objects Implant would combat long-sightedness which is common in over 40s  Would replace laser surgery - which can leave patients still needing glasses Procedure costs £2,495 and is currently not available on the NHS  Scientists have developed a new technique that could see reading glasses banished forever. The operation involves placing a tiny implant - known as a 'Raindrop' inlay - underneath the cornea in a bid to reverse vision problems associated with ageing. It is hoped the painless procedure will combat a condition known as presbyopia, which diminishes our ability to focus on close-up objects as we get older. +2 The procedure - which costs £2,495 - takes around 10 minutes and involves placing the tiny implant underneath a flap in the cornea It is common among the over 40s and is one of the main reasons we are forced to buy reading glasses.  The technique was pioneered in America, but has made its way across the Atlantic and is now being used at Space Healthcare in Royal Leamington Spa, Warwickshire. It could replace laser surgery, which until now has been deemed the only long-term treatment, even though it leaves some recipients requiring reading glasses in dim light.  +2 The new technique could replace laser eye surgery - which can leave some patients still needing glasses The procedure also takes just 10 minutes, whereas laser surgery can last for up to an hour. Anaesthetic droplets are inserted into the patient's eye so they remain conscious throughout as the implant is placed under a flap of the cornea, the clear part of the eye. It corrects near medium vision by changing the shape of the cornea, with the central section becoming steeper.  Lynda Marenghi, 57, a school bursar from Staffordshire, was the first person in Britain to undergo the procedure. She told The Sunday Telegraph: 'It was driving me mad, having to hold books further and further away from me and squinting to try to read them.' 'It felt like my arms were too short and I was diagnosed with presbyopia – losing my near sight. 'It’s an age-related thing and meant I had to wear glasses more and more which was awful because, being a school bursar, I have to deal with a lot of close work and spreadsheets on computers. The procedure costs £2,495 and is not currently available on the NHS. Mark Wevill, an opthalmic surgeon who has completed the surgery on a handful of patients, told the paper: 'Raindrop can't stop eyes from ageing. But it can help deterioration in eyesight caused by the ageing process. The new procedure offers hope to the 32million spectacle wearers in the UK and could reduce the £2.7billion a year spent on optical products - including contact lenses.