The view looking in

From the spring 2015 edition of Care and Cure research magazine, find out about how researchers can scan brains for signs of Alzheimer's disease.

Dr Paul Edison is a clinical senior lecturer at Imperial College London and is being funded by Alzheimer's Society to run a clinical trial of a diabetes drug against Alzheimer's disease.

When Edison was first training to be a doctor, dementia was a very poorly understood disease:

'I was attracted to dementia research by the lack of understanding about the disease. I have always been interested in finding novel methods of diagnosis and trying to understand what causes damage to the brain.'

Although we still haven't reached the day where we can understand and treat dementia, Edison has brought us closer.

He heads a team of researchers who use brain-scanning techniques to explore the mechanisms of Alzheimer's disease. His team was one of the first to use scans to detect the build-up of amyloid protein in the brains of people with Alzheimer's. They thought their approach might prove to be the definitive diagnostic test.

Edison says:

'But we've since found it's not specific for Alzheimer's. Amyloid deposits are found in the brains of people with other types of dementia,'

This disappointment led to another important observation - about 25 per cent of people around age 75 have high levels of amyloid in their brain, but don't have any symptoms of dementia. Edison thinks there are different ways to explain this.

'Perhaps what we're seeing are people at the early stages, and perhaps in 15-20 years' time, they would have Alzheimer's. But the other interesting possibility is that amyloid is not the only problem. Something else might be causing the nerve damage.'

There are a number of possible causes of nerve damage, including brain inflammation and the build-up of another protein called tau. Edison's team are studying how these processes are linked.

'We want to find out if all these processes are abnormal at the same time, or does one lead to another? Which comes first and how do they interact? And importantly how does this all relate to brain function and symptoms of dementia? Understanding this might lead to a clearer diagnosis and more options for treatment.'

There is another strand to Edison's work that directly relates to finding a treatment, as he explains:

'There's a strong relationship between Alzheimer's disease and diabetes. People with Type 2 diabetes are more likely to develop dementia. It's not just a result of damage to blood vessels in the brain. We think there could be a common mechanism - resistance to insulin.'

Insulin not only affects blood sugar levels, it also acts as a signalling molecule between nerve cells. In Alzheimer's, the nerve cells appear to stop responding to insulin. Drugs used to treat diabetes restore the effects of insulin, which raises the possibility that they might also treat dementia. 

Edison's team is conducting a study to test one such diabetes drug, liraglutide.

'If it's successful, if we see an improvement in memory, then we can take the drug to the clinic very quickly, because we already know it's safe for patients, because it's already used to treat people with diabetes. We just need to find out if it's effective.'

For further information about these studies, contact the team on [email protected], 020 8383 3704 or 020 8383 1969.

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