Vascular dementia – where are the drugs?

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By Robin Brisbourne | Wednesday 16 August 2017

With each heartbeat, blood vessels deliver around 15% of your blood up into your brain. This energy-hungry organ can only keep going thanks to the constant supply of nutrients and oxygen that are carried to it in the blood.

Hundreds of miles of arteries, veins and capillaries circulate blood around every inch of the brain. If this intricate network of blood vessels becomes damaged, or something interrupts the flow of blood, brain cells can stop functioning properly and die. This is what underlies vascular dementia, the second most common cause of dementia and a condition that affects around 150,000 people in the UK.

While there are no treatments that can stop the spread of a disease like Alzheimer’s through the brain, there are at least some drugs that can help with the symptoms. For vascular dementia, there are no such medications, and in a session at last month’s Alzheimer’s Association International Conference, researchers posed the critical question – “Where are the drugs?”

The here and now

Let’s start with the good news. There are some ways people can reduce the risk of vascular dementia and keep blood vessels in the brain healthy for longer. Stroke is a common cause of vascular dementia that can be tackled with medications or lifestyle changes to reduce the risk of blood clots, control blood pressure and keep cholesterol levels in check.

While it is important never to overlook the things that can help people with dementia in the here and now, researchers are keenly aware of the desperate need for better ways to tackle vascular dementia, and crucially, for treatments that improve the symptoms people experience.

Better drugs will need better trials

At the conference, leading international experts highlighted challenges from previous trials of vascular dementia drugs and outlined key lessons that will help future efforts.

One difficulty researchers face is that vascular dementia is not caused by a single discrete disease process. As well as strokes, it can also be caused by small vessel disease, a narrowing of small blood vessels deep inside the brain. A treatment may help people with one form of the disease but not the other, so it is important to make sure that a drug is being tested in the right group of people.

Unlike other forms of dementia, vascular dementia doesn’t tend to get steadily worse over time. Symptoms can remain stable for long stretches before progressing suddenly in a distinct step. This unpredictable development means that it can be especially difficult to measure how a drug could be affecting a person’s symptoms. Speakers at the conference pointed to the need for longer periods of testing to build a clearer picture of a drug’s impact on people’s lives.

Researchers with their fingers on the pulse

As well as these practical considerations, there are key scientific challenges in the way of better trials. But thanks to your support, Alzheimer’s Research UK is funding £4 million of pioneering research to help overcome these hurdles and pave the way to better treatments for vascular dementia.

Hitting the right targets – Prof Barry McColl

To get to grips with tackling any disease, we need to understand what is actually causing it. Some previous trials have been unsuccessful because they have not focussed on the processes that are most relevant to how nerve cells become damaged. Researchers in Edinburgh are investigating how changes in blood flow could trigger the brain’s immune response and whether this process could be contributing to nerve cell damage in vascular dementia.

Measuring change – Prof Hugh Markus

Drug trials can fall down if there isn’t a good way to measure what effect a drug is having in the brain. Biological tests that indicate how well a drug is working are critical if researchers are to develop better trials.

Prof Hugh Markus aims to identify features on MRI brain scans that can be used to evaluate new vascular dementia treatments more effectively than current methods. An MRI technique like this could be a vital boost for early stage clinical trials – reducing costs while letting researchers know which treatments should go on to final testing. This approach would allow researchers to take more new drugs into testing and help get effective treatments into the hands of patients sooner.

Pursuing the most promising drugs – Dr Jill Fowler

Before drugs are tested in people they need to undergo rigorous laboratory testing so that only the most promising potential treatments go into clinical trials. Alzheimer’s Research UK Senior Research Fellow Jill Fowler is working with mice with features of vascular dementia to see if an experimental drug could boost levels of a protein that kick-starts the brain’s cellular defence mechanism.

Developing new dementia treatments is an uphill struggle. But it’s a challenge that unites thousands of dementia researchers working in labs and clinics the world over. Just like all diseases, research into vascular dementia has its own particular set of challenges. But thanks to your support, researchers are closing in on treatments that will transform the lives of people living with vascular dementia.

If you want to be part of research that is helping us to understand dementia, you can sign up to volunteer for studies at www.joindementiaresearch.nihr.ac.uk or by calling our Dementia Research Infoline on 0300 111 5 111

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Robin Brisbourne

Team: Science news