Amyloid is a protein that is expressed in many different organ systems. When amyloid gets misprocessed and accumulates, it causes neurodegeneration. One of the hallmarks of Alzheimer’s disease (AD) is the accumulation of amyloid plaques (abnormally configured proteins) between nerve cells (neurons) in the brain. Amyloid-beta (Aβ) is a small, sticky portion of the amyloid protein that contributes to plaque formation. A healthy brain is able to break down amyloid-beta and eliminate it, but in AD, Aβ forms insoluble plaques that are toxic to neurons and sometimes (not always) associated with AD-related memory loss and other changes.
Previously, amyloid accumulation could only be observed after an autopsy, but advances in neuroimaging and biomarker assessments have made it possible to measure Aβ plaque buildup over time and learn which parts of the brain are most affected.
Anti-amyloid drugs are being tested in clinical trials, with the hope of preventing the formation of Aβ plaques in the future.
Role of Amyloid-Beta
Amyloid plaque deposits have long been associated with neurodegeneration in Alzheimer’s disease (AD); however, the precise ways in which the toxic Aβ damages neurons are still being explored.
What we know is that dense deposits of two proteins, Aβ, and tau, overtake the brains of people with Alzheimer’s disease, and the brain suffers atrophy, neuronal cell death, and damaged blood vessels, which deprives the brain of oxygen and nutrients and causes toxins to accumulate.
It seems that Aβ deposits drive all other changes in the brain that are associated with AD (including tangled deposits of tau, blood vessel deterioration, neuronal cell death, and brain atrophy). But exactly how and why is still unclear.
Explore More of Our 360° Research Approach
- Tangling with Tau
- Blood and the Brain in Dementia
- Immunity and Inflammation
- Biology of APO E and Lipids
- Cell Death
- New Approaches
Genes are the “master blueprint” that instructs our cells to make unique proteins which in turn build, operate, and repair human tissue. Humans have an estimated 24,000 genes along our 23 matched pairs of chromosomes (46 in all), and “genomics” refers to the field that studies all of them at once.
A biological marker (biomarker) is a measurable substance in an organism whose presence is indicative of some phenomenon such as disease or infection. Biomarkers can help doctors and scientists diagnose diseases and health conditions, find health risks in a person, monitor responses to treatment, and see how a person's disease or health condition changes over time.
Tangling with Tau
Tau is a small protein with a short name but a large reputation because of its association with multiple brain diseases, including Alzheimer’s disease (AD). The tau protein is predominantly found in brain cells (neurons).
Blood and the Brain in Dementia
Scientists are interested in developing a screening tool for Alzheimer’s disease (AD) in blood. A simple blood draw is much less invasive than a spinal tap and may prove more cost effective. Developing blood biomarkers that accurately depict brain changes has proven challenging, as levels of AD hallmark proteins in the blood are low, but there are some very recent promising results observing tau and the ratio of Aβ42 and Aβ40.
Immunity and Inflammation
One theory about Alzheimer’s disease (AD) is that it may be triggered, in part, by a breakdown in the brain’s immune system.
Biology of APO E and Lipids
Alzheimer's disease (AD). Its primary function is to regulate a class of proteins involved in the metabolism of fats (lipids) in the body. However, APOE has several common variants (or "alleles") whose effects vary.
The human brain has an estimated 100 billion neurons. Extending from each of them is a long fiber, known as an “axon,” which can run several feet. Each axon forms a connection, known as a “synapse” with another neuron, creating a circuit over which brain signals travel. In Alzheimer’s disease (AD), individual neurons die and do not regenerate; while others have brains that are more are resilient and respond to meet changing demands.
Years of innovative and dedicated research have paid off with the discovery of numerous factors contributing to Alzheimer’s disease (AD) pathology. With a disease as complex as this one, it’s very helpful to find multiple points where it may be possible to slow or halt its progress.