Newly developed test measures amyloid beta in the blood
Decades before problems like memory loss and confusion arise in people with Alzheimer's, there are factors that indicate the disease. The so-called amyloid beta plaques begin to form in the brains of these people. These seem to contribute to the progression of the disease. However, previous tests are expensive and not available everywhere. A newly developed blood test could now diagnose early onset Alzheimer's diseases.
In their current research, Washington University School of Medicine researchers found that a simple blood test may be able to detect the first signs of Alzheimer's in the future. The doctors released a press release on the results of their study.
New blood test can detect Alzheimer's early
The current methods for determining amyloid beta in the brain are so-called PET scanning or a specialized invasive method. If a blood test can identify amyloid beta in the blood, it will be possible to detect people with altered amyloid concentrations in their brain or cerebrospinal fluid early, the experts say. "Our results show that this blood test can detect whether amyloid beta has accumulated in the brain," said author Dr. Randall J. Bateman. This could be the basis for a quick and inexpensive blood screening test.
How does amyloid beta accumulate?
The brain continuously produces and deletes amyloid beta in its daily tasks. Amyloid beta is washed into the blood and also gets into the cerebrospinal fluid. If the amyloid beta forms so-called plaques, it adheres to neutrons and triggers neurological damage, the researchers explain.
Medical professionals are looking for amyloid beta 38, amyloid beta 40 and amyloid beta 42
A blood test would be cheaper and less invasive than PET scans. Previous studies had found, however, that the total concentration of amyloid beta in the blood did not correlate with the concentrations in the brain. Therefore, the scientists searched for three amyloid subtypes in the blood level of the test persons with the help of mass spectrometry: Amyloid beta 38, Amyloid beta 40 and Amyloid beta 42. They wanted to determine whether any of these subtypes were correlated with the level of the amyloid in the brain.
Experts examine around 40 subjects for their study
For their study, the experts examined 41 people aged at least 60 years. Twenty-three of the subjects were amyloid positive. This means that they show signs of cognitive impairment, the scientists say. Previously, PET scans or other invasive procedures had detected the presence of amyloid plaques in the brain or amyloid changes in the cerebrospinal fluid in these patients. The researchers also measured the amyloid subtypes in the 18 people who had no amyloid plaque accumulation in the brain.
People with amyloid plaques had lower levels of amyloid beta 42 and 40 in the blood
The researchers took twenty blood samples from each person over a 24-hour period. The experts found that the levels of amyloid beta 42 and amyloid beta 40 in the blood were consistently 10 to 15 percent lower in people with detectable amyloid plaques. The amyloid plaques consist mainly of amyloid beta 42, explains author Bateman.
Blood test for dew could complement the newly developed test
Amyloid plaques are one of the two characteristic signs of Alzheimer's disease. The other sign is the presence of so-called tau tangles. A blood-based test for tau proteins is already being developed, which could supplement the amyloid test in the future, the experts explain. "If we also had a test for tau, we could combine both tests to get an even better idea of which people are most at risk of developing Alzheimer's," explains Bateman. This would be a big step in predicting Alzheimer's disease. (as)