A potential stem cell therapy for glaucoma – a degenerative eye condition that can lead to blindness – has yielded positive results in animal tests. The treatment led to a 50 percent improvement in vision in rats with a model of the disease.
Glaucoma is a condition where pressure builds up in the eye, resulting in the death of retinal ganglion cells (RGCs) that normally form optic nerve fibres and help transmit information from the eye to the brain. It affects about 500,000 people in the UK, and 70 million people across the world. One in ten people with the disease go blind, often either because they were diagnosed too late or because their condition was too severe to be treated. In such cases, there is currently no way to reverse the blindness.
In this study, scientists at University College London, and Moorfields Eye Hospital, used adult stem cells called Müller glia cells. These rare cells, in this case isolated from corneas from organ donors, are multipotent, meaning they can develop into any type of eye cell. The scientists induced the Müller glia cells to develop into precursors to RGCs, then placed them in rats whose RGCs had been damaged in a way to simulate glaucoma. After four weeks the cells had not merged with the afflicted rat cell population but instead formed new bridges between undamaged sections. Under very low light conditions, the rats' vision had improved by 50 percent.
Dr Astrid Limb of the UCL Institute of Ophthalmology, and leader of the research team, said: 'Although this research is still a long way from the clinic, it is a significant step towards our ultimate goal of finding a cure for glaucoma and other related conditions. We are optimistic that [...] we will be in a good position to start early-stage clinical trials on humans in around three to five years'.
Dr Rob Buckle, head of regenerative medicine at the Medical Research Council (MRC), which funded the research, said: 'Regenerative medicine is a key priority for the MRC and it's wonderful to see another example of how our significant investment in stem cell research in recent years is beginning to deliver results. Repair of the eye is an area that is now at the forefront of this field, and this study highlights a new route for delivering the promise of regenerative medicine to treat disabling conditions such as glaucoma'.
Other groups are also using stem cell technology to treat ocular diseases. The US company, Advanced Cell Technology, received the go-ahead earlier this year for a clinical trial to test a proposed stem cell therapy for advanced Stargardt disease – a leading cause of blindness in young people (reported in BioNews 642). That trial, which will be conducted in partnership with Moorfields Eye Hospital, will use human embryonic – rather than adult – stem cells.