Alzheimer's Research Recognize the diseases more quickly with a new blood test

Blood test shows history of Alzheimer long before the first clinical signs

The number of people suffering from Alzheimer's is increasing worldwide. The neurodegenerative disease is still incurable. According to experts, this could also be because the previous therapies begin too late. In the future, that could change. With a new blood test, Alzheimer's can be found long before the onset of illness.

Incurable disease

In Germany alone, about 1.2 million people suffer from dementia, the majority of them from Alzheimer's. There are around 47 million dementia patients worldwide. And there are more and more: According to the World Alzheimer's Report is every 3.2 seconds another dementia diagnosis. The disease is not yet curable. According to experts, this could also be related to the fact that the previous therapies are only starting late, partly because the disease is often diagnosed late. However, a research team reports now that Alzheimer's traces are found long before the onset of illness in the blood.

Researchers were able to show that the occurrence of Alzheimer's disease can be closely tracked long before the onset of the first clinical signs from a protein present in the blood. This blood test offers new opportunities in therapy research. (Image: StudioLaMagica / fotolia.com)

Early diagnosis important

As with many other diseases, it is important in Alzheimer's disease to diagnose the disease as early as possible.

Although the disease can not be cured at this time, there are indications that a delay in the course of the disease can be achieved if diagnosed early.

Helpful for therapy research could be a new blood test.

Nerve cells are slowly degraded

Years before the first symptoms of Alzheimer's disease appear, the brain changes and nerve cells are slowly degraded.

Scientists at the German Center for Neurodegenerative Diseases (DZNE), the Hertie Institute for Clinical Brain Research (HIH) and the University Hospital Tübingen now show that the disease can be tracked well before the onset of the first clinical signs using a protein found in the blood.

As it says in a joint press release, this blood test offers new opportunities in therapy research.

The study was conducted in collaboration with an international research team and published in the journal Nature Medicine.

Previous therapies are starting too late

"The fact that there is still no effective treatment for Alzheimer's is probably due to the fact that the existing therapies are far too late," said Mathias Jucker, a researcher at the DZNE site in Tübingen, at the HIH and head of the current study.

Therefore, to develop better treatments, scientists need a reliable way to track and predict disease progression before symptoms such as memory impairment begin.

A blood test is much better than, for example, expensive brain scanners that make dementia more visible.

Some progress has been made lately in the development of such blood tests. For example, Japanese and Australian researchers reported a new screening test early last year.

And German scientists have also developed a blood test for the early detection of Alzheimer's disease.

As stated in the current communication, most of these methods rely on the detection of so-called amyloid proteins. In Alzheimer's disease, these proteins accumulate in the brain and they also appear in the blood.

But Jucker and colleagues have a different approach. "Our blood test does not measure amyloid, but what it does to the brain, namely neurodegeneration. In other words, the death of nerve cells, "said Jucker.

Traces in the blood

When brain cells die off, their remains can be detected in the blood. "Normally, however, such proteins break down rapidly in the blood and are therefore not very well suited as markers for a neurodegenerative disease," said Jucker.

"An exception, however, is a small piece of a so-called neurofilament, which is amazingly resistant to this degradation".

The blood test is based on this protein by Jucker and his colleagues.

The scientists show in the current study that the filament accumulates in the blood long before the onset of clinical symptoms - ie already in the so-called preclinical phase - that it very sensitively reflects the course of the disease and allows predictions about future developments.

According to the data, the study is based on data and samples from 405 individuals surveyed by an international research network called the Dominantly Inherited Alzheimer Network (DIAN).

In addition to the DZNE, the HIH and the University Hospital Tübingen are also involved the Washington University School of Medicine in St. Louis (USA) and other institutions around the world.

This network is investigating families that have Alzheimer's disease as early as mid-life due to genetic alterations. Genetic analyzes allow fairly accurate predictions as to whether and when a family member will develop dementia.

Harbingers of dementia

In these individuals, scientists followed the evolution of filament concentration from year to year, noting that up to 16 years before the expected onset of dementia, there were abnormal changes in the blood.

"It is not the absolute value of the filament concentration, but its temporal evolution, which is really meaningful and allows predictions about the further course of the disease," said Jucker.

In further investigations, the researchers showed that the change in neurofilament concentration accurately reflects neuronal degradation and allows good predictions of how the brain will develop over the next few years.

"We were able to make predictions about the loss of brain mass and cognitive impairment that actually occurred two years later," says Jucker.

Thus, while it was found that the rate of change of filament concentration and the degradation of brain tissue correlated closely, the relationship with the deposition of toxic amyloid proteins was much less pronounced.

This observation supports the assumption that although amyloid proteins are a causative agent of the disease, neuronal degradation is independent in the process.

Tool for therapy research

Not only in Alzheimer's, but also in the course of further neurodegenerative diseases, it comes in the blood to the enrichment of neurofilaments.

Thus, the test is only conditionally suitable for the diagnosis of Alzheimer's.

"The test is a very accurate indicator of disease progression, making it an excellent tool to explore new Alzheimer's therapies in clinical trials," said Jucker. (Ad)