Alzheimer's drugs may prevent glaucoma
6 August 2007
A team of researchers at the UCL Institute of Ophthalmology has found that a combination of treatments developed for Alzheimer's disease also has the potential to treat glaucoma, the major cause of irreversible blindness worldwide.
The project, funded by the Wellcome Trust, initially developed a new technology for visualising nerve cell damage in the retina, called detection of apoptosing retinal cells. The new technique enabled the team to discover that the protein beta-amyloid, responsible for plaque lesions in the brain in Alzheimer's patients, also causes nerve cell death in the retina.
The team then went on to look at a number of novel drugs currently undergoing clinical trials for Alzheimer's disease that target beta-amyloid with a view that could also prove to effective in treating glaucoma. The findings are published online in the journal 'Proceedings of the National Academy of Sciences of the USA'.
Project leader Dr Francesca Cordeiro said: "We've seen for the first time that there is a clear link between what causes Alzheimer's disease and one of the basic mechanisms behind glaucoma. However, this doesn't mean that everyone with Alzheimer's will develop glaucoma or vice versa. Glaucoma has a number of risk factors."
Glaucoma affects more than half a million people in the UK and as many as 65 million people worldwide. Little is known about what exactly causes the disease, which causes damage to the optic nerve in the eye, although the disease is traditionally attributed to increased pressure in the eye, known as 'intraocular pressure'. The new research opens up a new avenue of treatment in glaucoma that does not involve treating intraocular pressure.
Dr Cordeiro's team have shown that drugs working to prevent the build up of the beta-amyloid protein in Alzheimer brains can be used to treat glaucoma in animal models. One such drug, Bapineuzumab, is already being used in clinical trials to treat Alzheimer's patients. However, the team has shown that when combined with two other novel Alzheimer's treatments, the effects on glaucoma are even stronger.
"We are trying a new approach which has never been tried before, not even to treat Alzheimer's disease," says Dr Cordeiro. "Our success in treating glaucoma in the lab by combining different Alzheimer's treatments represents a brand new treatment strategy."
Previous research led by Dr Cordeiro suggested that the retina could provide a window into the brain, allowing doctors to diagnose Alzheimer's disease by looking for evidence of nerve cell death. Alzheimer's disease is the most common form of dementia, with nearly 700,000 patients in the UK. This is expected to exceed one million people by 2025.
"Many even within medicine fail to realise that the retina, commonly examined by high street opticians when they look at the back of the eye, is actually an extension of brain tissue, travelling down the optic nerve into the back of the eye," said Dr Cordeiro. "High street opticians have been routinely looking at the brain in a more direct way than has been possible by high tech brain scanners such as MRI and CAT."
Dr Cordeiro believes that this knowledge may mean that the eye could also be used to test potential treatments for Alzheimer's disease: "Since we have shown that drugs for Alzheimer's disease can tackle glaucoma, then potentially we could use damaged retina to screen Alzheimer's drugs that target beta-amyloid build up."
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