Understanding amyloid's role in the brain & cognitive disorders

February 14 2023

Amyloid is a protein found in various tissues of the body, including the brain. In healthy individuals, the brain produces and clears out amyloid naturally, but when this process goes awry, it can lead to a buildup of amyloid plaques in the brain. These plaques have been linked to the development of Alzheimer's disease and other neurodegenerative disorders. In this post, we explore the role of amyloid in the brain, its effects on brain function, and current research into amyloid-related disorders.

Amyloid plaques are a hallmark of Alzheimer's disease, a progressive and debilitating neurodegenerative disorder that affects millions of people worldwide. These plaques consist of clusters of amyloid beta peptides, which are the protein fragments thought to play a key role in the development of Alzheimer's disease. Research has suggested that in individuals with Alzheimer’s disease, abnormal levels of beta-amyloid can disrupt communication between brain cells, trigger inflammation, and damage blood vessels in the brain. These effects can lead to a range of symptoms, such as memory loss, confusion, difficulty with language, and problems with spatial orientation.  In addition to Alzheimer's disease, amyloid accumulation has been linked to other neurodegenerative disorders, such as Parkinson's disease and Huntington's disease. Researchers are also exploring the potential role of amyloid in other neurological conditions, including traumatic brain injury and epilepsy.

Amyloid production is a natural process and not always harmful to the brain. But in the great majority of cases, in those with Alzheimer’s disease, abnormally high levels of amyloid are typically present. This is an important notion because to fight Alzheimer’s, it is critical to assess amyloid levels consistently, but tracking amyloid levels alone does not provide a foolproof diagnostic solution. Some individuals with high levels of amyloid never go on to experience the symptoms of Alzheimer’s disease, owing to individual factors about their genetics, environment, and life experiences. For this reason, even if methods for detecting amyloid levels with 100% accuracy were available, approximately 20 to 30% of cases would still go undetected. Everyone who develops Alzheimer’s disease, however, has very specific changes to their memory and thinking abilities, so the key to  understanding whether an abnormal level of amyloid in a person’s system is causing or will lead to cognitive impairment or dementia is consistent evaluation of the individual’s cognitive performance. Testing for amyloid levels, combined with a validated cognitive assessment to check for signs of cognitive impairment, gives physicians a more complete picture of the effects of the abnormal levels of amyloid on an individual’s cognitive function and informs an appropriate treatment protocol.

In recent years, there has been considerable interest in developing treatments that target amyloid in the brain. Most recently, lecanemab, marketed as Leqembi, received accelerated FDA approval, and there are more than 100 other drugs in the pipeline to treat Alzheimer’s disease. These new treatments are showing promise for reducing the level of amyloid in the brain to healthy levels. However, more research is needed to fully understand the complex relationship between amyloid and the brain, and to develop effective therapies that can target this protein safely and without disrupting other aspects of brain function.

As the number of people experiencing cognitive impairment increases, it is increasingly important for healthcare providers to help patients protect their brain health more proactively, such as by addressing modifiable risk factors, and to prepare their practices to meet rising patient demand for both cognitive testing and treatment. More efficient, sensitive cognitive testing will be a critical first step in empowering primary care providers to detect symptoms of cognitive impairment early and intervene as soon as possible. Learn about what research has shown about Linus Health’s digital cognitive assessment technology and its association with amyloid on our Scientific Publications page.