The blood-brain barrier in Alzheimer’s disease

Dementia is now a world-wide epidemic, and we need to use every inch of innovative science and creative thinking to drive forward progress at a faster pace than we have ever seen before.

The blood-brain barrier in Alzheimer’s disease
Reports suggest that most people with Alzheimer’s and other dementia-related diagnoses receive care at home. (File)

By Fiona McLean

Blood vessels are present everywhere in our bodies and deliver oxygen and fuel to organs to keep them working properly. Throughout our brains are a group of cells, which form a barrier between the blood and the nerve cells, called the ‘blood-brain barrier’. The main cell type present in the blood-brain barrier are endothelial cells. These cells act like a bouncer on the door of a nightclub and decide what gets into the brain or what gets ejected. However, in dementia-related diseases, such as Alzheimer’s disease, the blood-brain barrier stops working properly. This causes many problems, including letting toxic substances into the brain, incorrect usage of vital nutrients, such as oxygen and glucose, and failure to remove waste products from the brain. Blood-brain barrier failure can occur early in Alzheimer’s disease and may contribute to disease progression.

My research, at the University of Dundee and funded by Alzheimer’s Research UK, will investigate what causes the blood-brain barrier to stop working in Alzheimer’s disease. One of the main goals is to understand what changes occur to the blood-brain barrier before and after amyloid build-up. Amyloid is one of the key pathological hallmarks of Alzheimer’s disease and in over 80% of patients, amyloid is found embedded into the brain blood vessels, a condition called Cerebral Amyloid Angiopathy. The frequency of Cerebral Amyloid Angiopathy occurring in Alzheimer’s patients highlights further why it is important that we research the blood-brain barrier and how it is affected in Alzheimer’s disease.

Another goal of my research is to better understand what factors drive the development of Alzheimer’s disease. The cause of most sporadic cases is currently unknown; however, we do know that there are a number of modifiable risk factors linked to ‘metabolic syndrome’ which can increase the risk of developing Alzheimer’s disease. Metabolic syndrome is a cluster of conditions which occur simultaneously, including obesity, type 2 diabetes, high blood pressure, high levels of triglyceride (fat) in the blood, and low levels of high-density lipoprotein (“good” cholesterol) in the blood. A key part of my research is to find out how metabolic syndrome may drive Alzheimer’s disease and if it kicks off problems in the blood-brain barrier. It is vitally important to understand the sequence of events leading up to and following problems in the blood-brain barrier and to better understand how metabolic syndrome can worsen outcomes.

The bad news is that ‘metabolic syndrome’ is increasing in many countries and this may be a key factor in the rise of Alzheimer’s cases. However, the good news is that if we modify our lifestyles, up to 40% of dementia cases could be delayed or even prevented. It is really important to get the message out that by living healthier lifestyles you can protect your brain as only 33% of people think it is possible to reduce the risk. A public health campaign, “Think Brain Health”, has been launched to help raise awareness and give tips about how to look after your brain.

Dementia is now a world-wide epidemic, and we need to use every inch of innovative science and creative thinking to drive forward progress at a faster pace than we have ever seen before.  It is essential that research into Alzheimer’s disease and other dementia-related diseases are supported. Charities contribute tremendously to ongoing research but we need governments to deliver the ‘moonshot’ funding commitment that has been promised for years. There is currently no cure for dementia and Alzheimer’s disease, despite being the leading cause of death in some countries. One of the worst things about this devastating disease is that it not only takes your life, but along the way it can steal your memories, what makes you who you are. This is why we have to push harder than ever to understand Alzheimer’s disease and how to stop it.

The blood-brain barrier is the first line of defence to protect our brain. If we can keep the blood-brain barrier working, then we can protect the rest of our brain cells. There are currently no medicines for Alzheimer’s disease, which target the blood-brain barrier, meaning there is a whole area of potential drug discovery that is untapped and could lead to a new generation of treatments. My research is a first step towards creating those new medicines.

(The author is Alzheimer’s Research UK Fellow, University of Dundee. Views expressed are personal and do not reflect the official position or policy of

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