If a doctor diagnoses someone with Alzheimer’s disease, it is often too late. The condition has progressed too far to be treated. The scientists Dr. Philip Scheltens of the Amsterdam University Medical Center (UMC) in the Netherlands and Dr. Klaus Gerwert of the Ruhr University of Bochum (RUB), Germany, are working on a blood test that will make an early diagnosis possible. Partly thanks to the support of the Alzheimer Netherlands foundation, they will now able to continue working on this project for another two years. It involves the detection of bio-marker proteins, which are typical of Alzheimer’s disease. On average, blood tests can already point to Alzheimer’s disease eight years before the clinical diagnosis.
“Our simple and inexpensive blood test can detect the disease at a stage when it is still a-symptomatic and can identify people who are particularly at risk of developing Alzheimer’s,” says Gerwert,
Alzheimer’s diagnosis often comes too late
“Currently, promising drugs for treating Alzheimer’s disease are failing in clinical trials. Alzheimer’s disease is usually discovered at a later stage when therapy is in most cases too late,” Gerwert says.
Alzheimer’s disease has a deformity of the amyloid beta protein that begins 15 to 20 years before the first symptoms appear. The incorrectly folded proteins clump together and are deposited in the brain as amyloid plaques. The fact that something is wrong in the brain is in many cases only revealed when someone begins to develop the typical symptoms of Alzheimer’s such as forgetfulness.
The test consists of a combination of techniques. An immuno-infrared sensor can be used to measure the deformity of the amyloid beta protein in the blood. Using the so-called Simoa technology, the ratio of different amyloid-beta variants to each other can be determined. The two scientists have discovered which ratio indicates Alzheimer’s disease.
In 70 percent of cases, the blood tests identified people who later actually developed Alzheimer’s dementia. In nine percent of the cases, the test gave a positive result, but the subjects remained healthy.
The team of the two scientists is currently examining blood samples from an Amsterdam study with 200 volunteers. According to the current standard diagnosis, these test subjects are not yet clinically ill, but already feel subjectively cognitively limited. With the help of the test, the researchers now want to use the blood values to predict which test subjects will develop Alzheimer’s disease.
Blood tests as routine screening
“If the Alzheimer’s drug Aducanumab or another promising drug such as Gantenerumab gets the expected timely approval, there is an urgent need for a blood test as a routine screening to identify the groups at risk,” says Klaus Gerwert.
Medicines currently being tested in clinical trials may be able to block the progression of the disease if applied at this early stage. The test also enables the development of new therapeutic approaches.