Research

A funding boost for vascular dementia

We all know the importance of a healthy blood supply and nowhere is that more important than in the brain. Over two litres of blood flows around the adult brain every three minutes, delivering essential nutrients and oxygen to cells and transporting waste away. This relentless supply keeps the brain in a delicate balance. If it’s cut off, as happens in a stroke, the impact can have long-lasting and life-threatening effects.

Vascular dementia is a progressive decline in thinking skills due to changes in the brain’s blood supply. It affects around 150,000 people in the UK and one of the biggest risk factors for vascular dementia is stroke. However, there are a number of different types of vascular dementia and not all of them involve strokes.

Despite the fact that it is the second most common type of dementia, there are still fundamental gaps in our understanding of why people develop vascular dementia and how it should be treated.

Stroke and vascular dementia have often been studied separately, but a more joined up approach is needed in order to understand how they relate to each other. Alzheimer’s Society has joined with the Stroke Association and British Heart Foundation to change this. Together, we have awarded a total of £2.2 million to three projects that will fill critical gaps in our knowledge.

Rates, risks and routes

The largest of these projects is a national study to understand memory and thinking problems after stroke. Rates, Risks and Routes to Reduction of Vascular Dementia (R4-VaD) involves a team of experienced clinical researchers from hospitals in Cambridge, Edinburgh, Glasgow, Leicester, London, Manchester, Nottingham and Oxford. They will recruit 2,000 people who have had a stroke or ministroke and use a wide range of tests to find out why some develop cognitive impairment or dementia while others do not.

Studies so far have found a wide variation in the number of people who develop dementia after a stroke, and the reasons for this are not completely clear. It could be due to differences in the type or severity of stroke, pre-existing damage to small blood vessels in the brain, or differences in risk factors such as age and smoking. In the R4-VaD study, people will be given brain scans and tests of thinking and memory, in addition to genetic analysis and tests of vascular function and inflammation.

Professor Joanna Wardlaw, who leads the R4-VaD team, says, ‘Comparing those who do and don’t develop memory and thinking problems will help us determine how to predict vascular dementia, what causes it and how we can prevent it.

‘We will test memory and thinking skills at regular intervals for up to two years after people have had a stroke, along with information on tiredness, mood and ability to cope with daily life.

Factors that may cause development of memory and thinking problems could relate to clinical disorders such as high blood pressure, lifestyle factors like smoking, or pre-existing changes in the brain (measured using brain scans).

Professor Wardlaw says, ‘In the long run, the results will improve how we look for, and look after, thinking and memory problems due to brain vessel disease. They will help clinical teams give the best care, assist policy makers in planning services and help researchers run studies to find successful treatments.’

This study will advance our understanding of what causes vascular dementia, but also lay the groundwork for future efforts to prevent the condition.

‘In this project we are developing an infrastructure and strong national foundation that means future studies will be easier and cheaper to undertake, as well as being quicker, because suitable individuals will have been identified already,’ says Professor Wardlaw.

Underlying changes

Two further projects will investigate changes in brain cells that lead to vascular dementia. A project led by Professor Karen Horsburgh in Edinburgh will focus on a particular type of change to the vascular system of the brain.

About of a quarter of strokes are caused by a failure of small blood vessels in the brain to regulate blood flow properly. Called cerebral small vessel disease, it is the most common disease process underlying vascular dementia.

Professor Horsburgh’s team have previously contributed to research showing that a mutation in a gene called collagen 4 can increase a person’s chances of stroke. In this project, the researchers want to understand how this gene affects the relationship between the brain and its blood supply.

They will use stem cells from humans along with animals that have been given the genetic mutation to find out what happens at the molecular level. By finding the mechanism that causes the blood supply to be impaired, the researchers hope to identify how drugs could intervene to prevent damage.

Another project looking for insights that could lead to new treatments, but taking a different angle, is led by Dr Roxana Carare at the University of Southampton. This will consider whether a failure of the blood’s waste removal function could play an important role in vascular dementia. Dr Carare will investigate how the brain’s waste clearance is affected by small vessel disease, and how this could contribute to brain cell damage.

Joint effort

Together, these grants represent a joint effort from three charities and three teams of researchers to answer fundamental questions about vascular dementia. If successful, these projects will move us closer to finding new treatments for people with vascular dementia, and help to identify who is most likely to benefit from them. This substantial investment has the potential to bring vascular dementia research out of the shadows.

Living with vascular dementia

Danny Brown (pictured above) has vascular dementia and lives in Antrim, Northern Ireland. He says, ‘I can remember things from 20 years ago, but I have difficulty with my short term memory. I use prompts to remind me to do things like turn off the oven. I don’t remember names and who people are, it’s an embarrassment.’

Danny first noticed problems with his memory around 10 years ago, and had a stroke in 2009. After a series of scans and assessments, Danny was diagnosed with vascular dementia in 2014.

Danny says ways to improve diagnosis could be helpful but it’s a difficult task. ‘It would take the best brains in the world to put something in place so that if someone’s losing memory they could within a few months have the right diagnosis.’