In the making: blood test for Alzheimer’s disease

Diagnosing Alzheimer’s disease is often a problematic process. Over the years, the field of biotechnology has tried to come up with screening and testing methods that can help identify this disease. While diagnostic biomarkers for many diseases can be identified in a blood sample, this has so far proved elusive for Alzheimer’s. However, there is a lot of promise in biomarkers found in the cerebrospinal fluid (CSF), which makes a lot of sense – considering the CSF’s proximity to the brain. CSF is a colorless liquid found in the central nervous system (brain and spinal cord).

Taking CSF samples however is a bit controversial since it entails a procedure called a lumbar puncture or spinal tap, which is basically done inserting a needle in the lower part of the spine to collect the fluid. A spinal tap is performed to diagnose diseases affecting the nervous system.

Many experts feel that a lumbar puncture can be painful and presents some risks, complicated by the type of patients – elderly and disoriented – one is dealing with. Others claim that a lumbar puncture is essentially safe and straightforward. This controversy in relation to the CSF has led many researchers to explore further the possible of developing a blood test for Alzheimer’s.

And it seems that their efforts are bearing fruit.

American researchers “have revealed a direct relationship between two specific antibodies and the severity of Alzheimer’s disease symptoms, raising hopes that a diagnostic blood test for the devastating disorder is within reach.”

The researchers focused on antibodies that the body produces in response to two Alzheimer-associated proteins. One of these proteins is the well-known amyloid-beta which is responsible for the formation of plaques in the brains of Alzheimer’s patients. The other protein is the less known RAGE which is involved in the normal human aging process. However, it has been observed the RAGE is expressed at higher levels in the brains of people with Alzheimer’s.

The researchers found that anti-amyloid beta and anti-RAGE antibodies are significantly higher in the group with Alzheimer’s compared to a control group without Alzheimer’s. Furthermore, the concentrations of the two antibodies in the blood seem to be significantly associated with the severity of the disease.

According researcher Shyamala Mruthint

“Alzheimer’s is an inflammatory disease of the brain, and these two antibodies give us a way to measure that inflammation. Using them as an early diagnostic marker may allow us to start drug treatment early, when it’s most effective, to increase the patient’s quality of life.”