A possible biomarker to distinguish Lewy body disease from other neurodegenerative disorders

The diagnosis of a neurodegenerative disease is often complex. In many cases, doctors must be guided only by clinical signs, which makes it difficult to identify the ultimate cause of the disorder and distinguish between diseases whose symptoms overlap.

Having biomarkers that allow us to accurately recognize these disorders is one of the objectives pursued by different research teams around the world, a goal that this week brings a little closer to a study from the Karolinska Institute in Sweden..

According to their data, measuring the levels of an enzyme that is key in the synthesis of neurotransmitters such as dopamine – DOPA decarboxylase (DDC) – in the cerebrospinal fluid and even in the blood could allow us to identify patients with Lewy body disease. before this type of neurodegenerative disorder begins to show marked symptoms, which encompasses both diseases such as Parkinson's and other neurodegenerative disorders, such as Lewy body dementia..

These disorders share similarities in terms of the cellular damage suffered by the brain and the symptoms that patients develop, especially in the initial phases of the disease.. In some brain cells of people who suffer from this problem, aggregates of alpha-synuclein accumulate, preventing proper neuronal functioning and causing alterations in movement, cognition and behavior..

The details of the work, which are published in the latest issue of Nature Aging, also show that the levels of this enzyme are also elevated in other atypical parkinsonisms, such as multiple system atrophy.. On the other hand, they do not change significantly in other types of neurodegenerative diseases, such as frontotemporal dementia or Alzheimer's..

“Our data show that this enzyme could have, in the future, a role in clinical practice as a biomarker of dopaminergic dysfunction to detect parkinsonism even in preclinical phases of the disease,” the authors point out in the scientific journal..

The researchers first analyzed the concentration of 2,943 proteins in the cerebrospinal fluid of 81 patients with Lewy body disease and 341 people without any type of neurodegenerative disease (controls), which allowed them to uncover the role of the aforementioned DDC enzyme..

With these data in hand, they corroborated their findings in a group of patients who were not taking any type of dopaminergic medication, a common treatment in patients with neurodegenerative movement disorders, to rule out possible biases.

The analyzes carried out showed that the biomarker could be a useful tool not only to identify Lewy body disease but also to detect the problem in early stages, when the symptoms are not yet very marked..

In a next step of the research, the researchers wanted to check whether patients with atypical parkinsonisms, such as multiple system atrophy, corticobasal syndrome or progressive supranuclear palsy, also had high levels of DDC, a thesis that they verified.

And, finally, they corroborated in a smaller sample of patients (64 patients with Lewy body disease, 54 controls and 56 people with atypical parkinsonism), that the biomarker was also detectable in plasma and allowed the affected patients to be correctly identified, which which could facilitate its use in clinical practice.

For Álvaro Sánchez Ferro, coordinator of the Movement Disorders Study Group of the Spanish Society of Neurology, it is undoubtedly “a very interesting study”, although we must not forget that “the research is still in a very initial phase ” and does not show whether the proposed biomarker can be useful in “disorders such as essential tremor, among others”.

Having biomarkers in clinical practice that help discriminate disorders can be a very effective tool, says the specialist, who recalls that, today, “there are no curative treatments for Lewy disease.”. Yes, there are therapies that can address the symptoms, but currently there is no medication or approach that can end the disorder..