New blood tests have found early signs of dementia and ALS

A new blood test has been developed in Germany that is able to identify specific biomarkers of diseases such as FTD, ALS and PSP, offering hope for early diagnosis and more effective treatment of these serious neurodegenerative diseases.

In a study of 991 adults, German scientists showed that the most common frontotemporal dementia, as well as neurological diseases amyotrophic lateral sclerosis and progressive supranuclear palsy, can be identified by blood tests.

Their surgery is not yet ready for routine medical treatment, but in the long run, it can facilitate disease diagnosis and advance the development of new treatments. The finding, published in the journal Nature Medicine, is based on the measurement of certain proteins in the blood, which are biomarkers.

Review of neurodegenerative diseases

Frontotemporal dementia (FTD), amyotrophic lateral sclerosis (ALS), and progressive supranuclear palsy (PSP) form a family of neurodegenerative diseases with overlapping symptoms, characterized by dementia, behavioral symptoms, paralysis and muscle atrophy, movement disorders, and other serious impairments. It is estimated that up to 60,000 people in Germany are affected by one of these diseases. Although they are relatively rare, their health effects are still severe.

Professor Anja Schneider, head of the German Center for Neurodegenerative Diseases (DZNE) research team and head of the Department of Geriatric Psychiatry and Cognitive Impairment at the Royal College of Medicine, explains: "So far, there is no cure for these diseases. Moreover, according to the current approach, it is not possible to make a conclusive diagnosis of the molecular pathology of these diseases during the lifetime of the patient, since brain tissue must be examined. ”

Advances in diagnostics and biomarker research

"However, in order to develop treatments and stratify patients according to their disease, a diagnosis of the underlying pathology is required. Only such stratification can test targeted, and therefore potentially effective, disease-modifying treatments. Schneider, who is also affiliated with the University of Bonn, continues.

"We now show that PSP, a behavioral variant of FTD, and the vast majority of cases of ALS with the exception of specific mutations, can be identified by blood tests, which also applies to their underlying pathology. For the first time, our study identified pathology-specific biomarkers.

"Initially, the application may be in research and therapeutic development. But in the long run, I think it's realistic that these biomarkers will also be used for everyday medical diagnosis. However, further research is needed. In fact, it is particularly important to determine how these biomarkers develop vertically, i.e., over the course of the disease, and early in their rise over the course of the disease. ”

A breakthrough in protein detection in diagnosis

The new blood tests, based on the measurement of so-called tau and TDP-43 proteins, can provide conclusive evidence for diagnosis. The "behavioral variants of FTD" that need to be studied here are particularly needed. This is because the symptoms of this most common type of FTD can be due to two different pathologies in the brain, the abnormal process, which can usually only be distinguished by the analysis of tissues after death.

Only in the case of a few diseases that are hereditary can DNA analysis provide certainty over the patient's lifetime. Now, even without mutations, blood tests can make an accurate diagnosis for a patient's lifetime. This, in turn, is a prerequisite for testing new therapies against these different FTD pathologies in clinical trials.

Abnormal aggregates in disease identification

"It is well known that tau and TDP-43 proteins play a key role in FTD, ALS, and PSP because they form abnormal aggregates in the brain of these diseases," Schneider said. However, the situation is different for different diseases. Our research shows that protein levels in the blood reflect the course of these diseases. ”

"We found that a combination of two markers is required for the diagnosis of behavioral FTD and its isoforms, and that TDP-43 is sufficient for tau proteins in ALS and PSP. However, for tau markers, we are actually looking at two specific variants of tau protein, the so-called isoforms. ”

Tiny bubbles of lipids

This method uses a special method: this is because proteins are not measured directly in plasma. These measurements are inconclusive, especially since tau proteins, which float freely in the blood, are often fragmented.

Instead, Schneider and colleagues determined levels of two forms of tau protein and TDP-43 protein found in so-called vesicles. These are tiny lipid bubbles secreted by the body's cells that can eventually enter the bloodstream. Through multi-stage preparation, including centrifugal blood samples, researchers were able to capture the proteins contained in vesicles.

Collaborative research

The results are based on data and blood samples from a study group of 991 adults in Germany and Spain. They were affected by FTD, ALS, PSP or were in the control group with healthy individuals. This situation with independent volunteer groups allowed the results of the study to be widely validated.

On the one hand, this concerns the so-called DESCRIBE cohorts: as part of these research initiatives, DZNE and several German university hospitals are compiling data and biological samples from patients with neurodegenerative diseases. This collection includes more than 700 patients. From the Spanish side, the "Sant Pau" team, operated by the "Santa Creu i Sant Pau Hospital" in Barcelona, joined the project, with more than 200 participants.

"For these relatively rare diseases, you have to work in different locations and institutes to involve as many study participants as possible to produce statistically reliable results," Schneider explains. "These commitments are an integral part of the DZNE strategy, for which we have established structures and procedures over the years. It's complicated, but it pays off. Our research is a good example of medical research cooperation between Germany and abroad. ”

Source: German Research Center for Neurodegenerative Diseases

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