Research

Researching links between dementia and blood vessels

Changes in the blood vessels can happen in many types of dementia, including vascular dementia, Alzheimer’s disease, and dementia with Lewy bodies.    

Interruptions in the brain’s blood flow can cause our brain cells to die and brain tissue to be damaged. It’s this damage which causes symptoms of vascular dementia, such as problems with thinking, reasoning, or memory.

Reduced brain blood flow and dementia

Reduced blood flow in the brain can happen because of blockages or leakages in the brain’s blood vessels. For example, dementia symptoms may start after a stroke, when a major blood vessel in the brain becomes blocked.  

Symptoms of vascular dementia can also start gradually, such as when smaller blood vessels get diseased over time.  

A condition called cerebral small vessel disease is also thought to be one of the main causes of vascular dementia. It damages blood vessels that supply vital oxygen and nutrients to brain cells. Research by PhD student, Miruna Burduja, funded as part of the Alzheimer’s Society Doctoral Training Centre (DTC) for Vascular and Immune contributors to dementia, aims to answer questions about vascular dementia and cerebral small vessel disease.  

Interruptions to the brain blood flow can happen in other types of dementia too. Researchers estimate that at least 70% of people who are diagnosed with Alzheimer’s disease may have damage to brain blood vessels.  

This area in dementia research has not been studied in depth, and we don’t understand all the mechanisms which could affect blood flow in the brains of people with dementia.  

If we understand these changes, we could find the ways to control and prevent them.

Tackling the underlying causes of vascular dementia

Right now, there’s no cure for vascular dementia. Researchers believe the best way to tackle it is to prevent or treat the conditions that cause it, such as preventing strokes or problems with blood vessels.

PhD students Hing Tim Fung and Eleanor Benford, funded as part of our DTC, are exploring how we can better understand and predict changes in memory and thinking associated with a stroke. Insights from these research projects could improve our knowledge of dementia, and how we can support stroke survivors and their families.

As the causes of vascular dementia are connected to how our heart and blood vessels provide the brain with blood, researchers are also investigating if there are associations between heart health and brain health as we get older.

Alzheimer’s Society has funded research led by Dr Sana Suri at the University of Oxford, who investigated how poor heart and large blood vessel health in midlife affects the health of our brains and our memory as we get older. 

Research like this could help us understand how to keep our brains as healthy as possible as we get older and tell us more about what different aspects of our lives could increase our chances of developing dementia later in life.  

Research shows that maintaining good cardiovascular health, which includes reducing blood pressure, treating high cholesterol, exercising regularly, and maintaining a healthy weight can reduce the risk of dementia.  

Alzheimer’s disease and the connection between blood vessels and brain cells

There’s much we don’t yet know about how our blood vessels link with brain health. PhD student Misha Ramesh hopes to analyse images of the eyes to get a better understanding of the brain blood vessels, and use this information to predict early signs of dementia.  

The blood vessels in the brain are regulated by the blood-brain barrier. This barrier acts as a gatekeeper preventing unwanted substances from crossing in and out of the brain, protecting it from harm.  

Recent studies suggest that people living with Alzheimer’s disease develop changes to the brain’s blood vessels, which can cause the blood-brain barrier to become defective. This involves changes in how different brain cells work, which can happen before any memory symptoms occur.  

One of our DTC PhD students, Noelia Pérez Ramos, aims to understand how brain cells influence blood vessels in the brain after bacterial infection in people with dementia.

Meanwhile, research by Dr Steven Hill at the University of Edinburgh, funded by Alzheimer’s Society, will investigate mechanisms behind how these brain cells change and how these changes cause harm to the brain in Alzheimer’s disease. Dr Hill will also evaluate potential therapies to determine whether we can prevent the onset or reduce the symptoms of Alzheimer’s disease.

Through this research, we’ll be able to gather more information about the early changes which take place in the brains of people living with Alzheimer’s disease.

How is the brain blood supply linked to the immune system and dementia?

When the blood supply to the brain is reduced, the brain becomes inflamed. This increases the number of immune cells, causing brain cells to die. This can also damage the immune cells themselves, so that they can’t function properly and can’t protect the brain from waste. This makes dementia symptoms worse.  

There are different types of brain immune cells, defined by where in the brain they are located. Some of those which sense and respond to injury or infection, can communicate with each other, but in Alzheimer’s disease, this communication becomes faulty, causing these cells to eat away connections between nerve cells. The nerve cells die, which contributes to the symptoms of dementia.  

Research by Dr Soyon Hong and her PhD student, Lais Sousa da Silva Ferreira, (UKDRI and University College London), funded by Alzheimer’s Society, aims to understand how and when brain immune cells become faulty in Alzheimer’s disease.  

By understanding these processes, researchers can learn if we can develop new ways of protecting the brain from damage.  

Looking forward to future dementia research

We’re committed to supporting research that would help us understand how blood vessels and immune cells contribute to developing dementia, and what we can do in the future to prevent the damaging processes from taking place.