Can this Test Predict Alzheimer’s Disease?
Lipids in the bloodstream may be the key to early detection
The Headlines:
Blood test predicts Alzheimer’s disease — CNN
Blood test could detect early signs of dementia, scientists say — The Guardian
Blood test can predict Alzheimer’s, say researchers — BBC
The Science:
What is Alzheimer’s Disease? Alzheimer’s is an irreversible loss of function in the brains of older adults that destroys memory and thinking skills to the point that patients eventually lose the ability to carry out everyday functions and care for themselves. It is the most common form of dementia (an umbrella term for age-related loss of memory and intellectual abilities) in older Americans, with over 5 million estimated current patients (NIA), and up to 35 million worldwide.
The physical damage to the brain that causes Alzheimer’s disease begins to appear in the years before symptoms of memory loss become apparent in patients — many scientists think that this is a key reason why most therapeutic treatments have failed, as they are simply reaching the patients too late, after irreversible damage has already been done. As the brain develops Alzheimer’s disease, it begins to accumulate both “neurofibrillary tangles” — disorganised meshes of protein fibers along nerve cells, as well as “amyloid plaques” — clumps of fatty protein that accumulate between the nerves. There is debate among scientists as to the precise role each of these plays in the development of Alzheimer’s disease, although symptoms begin to appear once this combination of “tangles” and “plaques” have significantly impaired the function of brain circuits, and even begun to cause widespread death of brain cells, leading to an irreversible loss of intelligence.
What did the Scientists Find? A team of scientists led by Howard Federoff from Georgetown University analyzed blood samples from 525 people over 70 as part of a multi-year study. They looked for a particular group of lipids (fat molecules) that are usually found in the cell membranes around nerve cells in the brain; by doing this, they were able to test if these lipids show up in elevated amounts in the bloodstream as the nerve cells start to die off due to Alzheimer’s. When they compared the blood levels of these lipids between two groups within the study — 53 who developed Alzheimer’s disease during the study, and 53 who remained mentally agile — they found that the Alzheimer’s group had significantly higher levels of these proteins in their blood. Moreover, they found that by looking at the relative levels of these 10 lipids in the patients’ bloodstream, they could predict with 90% accuracy which patients would develop memory loss and other Alzheimer’s disease symptoms within the next 2-3 years.
What’s the Next Step? In order to show that this test could become a clinical tool to screen older adults for Alzheimer’s onset, and thus lead to earlier and presumably more effective treatment/management of the condition, this test will need to be repeated with a much larger patient pool (~5,000 patients) to convince regulators and healthcare providers of its effectiveness. The team that published this study is also looking into whether testing for this group of lipids in the blood could be refined to give an even earlier pre-diagnosis than the 2-3 years they found here.
What does this mean for me?
If you are an older adult, and you begin to experience symptoms that might be Alzheimer’s disease, or if you notice these in a family member, you should talk to a doctor as soon as possible. While Alzheimer’s disease is currently not yet curable, there are a number of things that can slow down the progression of the disease, and it is important to develop a care plan for yourself while you are still able to, rather than leaving it up to others who may not share your priorities. If a test, such as the one in this article becomes clinically available, it may become part of regular screening for older patients, which will allow doctors and patients to treat the disease much earlier, and hopefully stop Alzheimer’s progression in its tracks.
Alzheimer’s is a complex disease with many causes, including both genetic and environmental. While we currently can’t be sure who will develop the disease and when, there are a number of things you can do now to reduce the likelihood that you will develop Alzheimer’s disease, or other types of dementia. Eating healthily, including fruits and vegetables, and limiting red meat and alcohol intake, regular exercise, and minimizing stress are all known to reduce the chances that you will suffer from dementia. It is important to remain mentally active, even in retirement, by challenging yourself with puzzles, or carrying out complex tasks. Your brain has a ‘use it or lose it’ economy — just like a muscle, it needs exercise to stay healthy and strong!
