How is blood flow linked to Alzheimer’s disease?

Rachel Harris is a PhD student with Prof Seth Love and Dr Shelley Allen at the University of Bristol. She’s interested in the role of blood flow in dementia.

In dementia, we know that what is good for the heart is good for the head and that keeping blood vessels healthy can help protect the brain and lower dementia risk. However, we’re yet to understand all the processes that link the vascular system and nerve cell health. Through my PhD, I hope to reveal more about the connection by studying a group of proteins which ‘talk to’ both nerve cells and blood vessels.

Alzheimer’s disease and vascular dementia are the two leading causes of dementia. Sometimes Alzheimer’s disease is seen with vascular dementia –part of what’s known as mixed dementia. We think that Alzheimer’s disease, mixed dementia and vascular dementia are not always entirely separate diseases, but are on a spectrum. Researchers are working hard to understand more about the similarities and differences, as this will improve diagnosis and treatment.


Vascular disease – which can often precede coronary heart disease or stroke – and dementia, share common risk factors, including high blood pressure, high cholesterol and smoking. Some researchers also found evidence of direct links between Alzheimer’s disease and the vascular system.

In vascular dementia the brain doesn’t receive enough blood, and therefore oxygen, which results in nerve cell death. We also know that blood flow to the brain is reduced in patients with Alzheimer’s disease and this may be part of the reason nerve cells are dying in this form of dementia too.

In Alzheimer’s disease, clumps of a protein called amyloid form around nerve cells in the brain. Amyloid also builds up inside the walls of brain blood vessels. This amyloid damages blood vessels and may interfere with blood flow in the brain. You can learn more about amyloid in blood vessels from our blog from the Alzheimer’s Research UK Conference earlier this year.

My research group previously found that a protein, known as vascular endothelial growth factor (VEGF), is expressed at higher levels in the brain of people with Alzheimer’s disease when we compare to the brains of healthy people of the same age. This protein is made all over the body and is switched on when there is not enough oxygen getting to the cells. In the lab we are trying to understand how this particular protein affects the brain in Alzheimer’s disease.

To do this, we are using brains donated for dementia research via the South West Dementia Brain Bank, a Brains for Dementia Research centre and part of the UK Brain Bank Network. We are also able to grow nerve cells in controlled conditions and then investigate the molecular chain of events going on inside cells. This helps us to understand how the changes we see in the human brains happen.

Right now we’re looking at how VEGF communicates with cells in the brain. It does this by sticking to receptors on the surface of nerve cells, brain support cells called astrocytes and blood vessels. Here are some pictures of nerve cells and blood vessels that are stained for these receptors.

Human brain tissue ‘stained’ to look for the proteins we’re interested in – they are expressed on brain support cells, blood vessels and nerve cells.

Human brain tissue ‘stained’ to look for the proteins we’re interested in – they are expressed on brain support cells, blood vessels and nerve cells.

Human brain tissue ‘stained’ to look for the proteins we’re interested in – they are expressed on brain support cells, blood vessels and nerve cells.

We hope that by understanding the pathways that lead to reduced blood flow to the brain in Alzheimer’s disease and vascular dementia we can develop new and effective treatments for the two biggest causes of dementia.


  1. Andrew Noble on 21st August 2015 at 1:52 pm

    Fascinating topic for a PhD, good luck for the coming years and the project.
    Looking positively forward to seeing what you can discover.

  2. Alyssa on 1st September 2015 at 2:21 pm

    Hello, we’re very interested in regards to research, with a completely different approach. We create Apps for research purposes. These apps are collating data for clinicians, and studies can be much larger with a much greater demographic. Our my LDN research app is the first, global, remote research study for one medication and 174 different conditions. On a personal note, my father (in Canada) is reaching the final stages of Alzheimers… And I believe that we can help make a difference to research. Please contact me? Thank you in advance. With gratitude, Alyssa

  3. Stephen Bothel on 28th November 2016 at 1:55 am

    Thanks for your research on this debilitating disease with one parent dead from this and the other failing fast .
    I do what I can to stimulate my mind and take care of weight exercise and blood pressure.
    I read everything I can on this all in a attempt to stack things in my favor.

    Stephen Bothel

  4. sheila gayle on 27th February 2017 at 2:38 am

    Very interesting. What about the possibility of low oxygen in the brain due to sleep apnea? Also, the brain cannot be rid of toxins if the mind does not go into rem sleep.

  5. Jack Messerlian on 5th March 2017 at 9:55 pm

    Outstanding pt of investigation- I.e relationship of blood flow to alzheimers disease . Wish you and yr dept publish results WHEN STUDIES are completed. Many thanks for yr efforts in this area of GREAT concern. Jack Messerlian Engr USA

  6. Jack messerlian on 6th March 2017 at 2:04 pm

    Excellent info for research to focus attention to.

  7. Sarah Winslet on 6th December 2018 at 11:46 am

    Thanks for apprising different types of dementia which is a syndrome and mostly affects the older adults. Alzheimer’s disease s one of the most common forms of such syndrome which affects the brain cells of a person which reduces the person’s analyzing and memorizing ability. Many people have no idea about such types of syndromes and often ignored. Lack of knowledge regarding such syndrome could be very dangerous. So, one should conduct a lot of research to know more about such types of syndromes to deal with loved ones affected by it. Unfortunately, such syndrome doesn’t have any cure.

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About the author

Rachel Harris

Rachel Harris is a PhD student with Prof Seth Love at the University of Bristol. She’s interested in the complex link between blood supply and brain health.