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New blood test can detect Alzheimer's disease years before the onset of the disease
Decades before people with Alzheimer's problems such as memory loss and confusion arise, there are factors pointing to the disease. In the brains of these people begins the formation of so-called amyloid beta plaques. These seem to contribute to the progression of the disease. However, previous tests are expensive and not widely available. A newly developed blood test could diagnose early-onset Alzheimer's disease at an early stage.
The Washington University School of Medicine researchers said in their current research that a simple blood test in the future might be able to detect the first signs of Alzheimer's. The doctors published a press release on the results of their study.
A newly developed blood test could help in the future that Alzheimer's can be diagnosed years before the first obvious signs of the disease. (Image: StudioLaMagica / fotolia.com) New blood test can detect Alzheimer's early
Current methods for detecting amyloid beta in the brain are a so-called PET scanning or a specialized invasive procedure. If a blood test can identify amyloid beta in the blood, it will make it possible to detect people with altered levels of amyloid in their brain or cerebrospinal fluid at an early stage, say the experts. "Our results show that this blood test can detect if amyloid beta has accumulated in the brain," said Dr. Randall J. Bateman. This could be the basis for a quick and inexpensive blood screening test.
How are accumulations of amyloid beta??
The brain continuously produces and deletes amyloid beta in its daily tasks. This amyloid beta is washed into the blood and also enters the cerebrospinal fluid. When amyloid beta forms so-called plaques, it adheres to neutrons and causes neurological damage, the researchers explain.
Physicians are looking for amyloid beta 38, amyloid beta 40 and amyloid beta 42
A blood sample would be cheaper and less invasive than PET scans. However, previous studies had found that the total concentration of amyloid beta in the blood did not correlate with brain levels. Therefore, the scientists looked in the blood level of the subjects with the help of mass spectrometry for three amyloid subtypes: amyloid beta 38, amyloid beta 40 and amyloid beta 42. So they wanted to determine whether any of these subtypes are correlated with the level of amyloid in the brain.
Experts are investigating about 40 subjects for their study
For their study, the experts examined 41 people over the age of 60 years. Twenty-three of the subjects were amyloid-positive. This means that they show signs of cognitive impairment, say the scientists. Previously, PET scans or other invasive procedures in these patients had already detected the presence of amyloid plaques in the brain or amyloid changes in the cerebrospinal fluid. The researchers also measured the amyloid subtypes in the 18 individuals who did not have accumulation of amyloid plaques in the brain.
People with amyloid plaques had lower levels of amyloid beta 42 and 40 in the blood
Researchers took twenty blood samples from each person over a 24-hour period for their examination. The experts found that 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 Tau could complement the newly developed test
Amyloid plaques are one of the two hallmarks 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, Bateman further explains. This would be a big step in predicting Alzheimer's disease. (As)