Parkinson's disease, Lewy body dementia: New biomarker found

• More than 10 million people globally have Parkinson’s disease.
• Diagnosing Parkinson’s disease can be difficult as there is currently no specific test.
• Researchers from Lund University in Sweden have identified a new biomarker that can be used to identify people living with Parkinson’s disease and other related diseases, even years before a person develops symptoms.

More than 10 million people around the world have Parkinson’s disease, a neurodegenerative disorder affecting a person’s ability to move.

Currently, no specific laboratory or imaging tests are available to diagnose Parkinson’s disease. Doctors can make a diagnosis based on any brain imaging and early symptoms. However, this can make prognosis difficult.

Now researchers from Lund University in Sweden have identified a new biomarker that can be used to identify people living with Parkinson’s disease and other related diseases, even years before a person develops symptoms.

This study was recently published in the journal Nature Aging.

What is a biomarker?

A biomarker — short for biological marker — is a medical sign that helps in the diagnosis of a disease or to indicate a physiological state of interest.

Biomarkers can be found in the body’s tissues, blood, urine, and other bodily fluids, and can be detected by analyzing a sample. They can also be detected at a cellular or molecular level such as by looking at a person’s genes.

A biomarker is also measurable. For example, a person’s blood pressure, body temperature, and body weight are considered physiological biomarkers as they provide measurable “snapshots” of where the body is in terms of health.

There are also molecular biomarkers, such as a person’s cholesterol level, or substances measured in a biopsy.

Over the past few years, researchers have focused on finding biomarkers for specific diseases, including Alzheimer’s disease, multiple sclerosis, kidney disease, eczema, and depression.

A new biomarker for Parkinson’s and related diseases

For this new research, Dr. Oskar Hansson — a professor of neurology at Lund University, consultant at Skåne University Hospital, and lead author of this study — and his team used advanced techniques to measure thousands of proteins in samples from 428 people.

Of the total number of participants, 347 acted as healthy controls, and 81 were people with Lewy body dementia, a condition that often occurs in Parkinson’s disease.

The scientists found that if a person had a disorder affecting their dopamine system — as is the case with Parkinson’s — they had an elevated level of a specific protein called DOPA decarboxylase (DCC) in their cerebrospinal fluid, regardless of where they were in terms of disease progression.

The researchers verified their findings in an additional group of study participants, and found that the new biomarker also significantly increased in their bloodstream, providing a safer diagnostic tool and method.

“This study shows for the first time that the protein DCC is elevated in both cerebrospinal fluid and blood in patients with Parkinsonian disorders, including Parkinson’s disease, Lewy body dementia, progressive supranuclear palsy, and multiple system atrophy,” Dr. Hansson told Medical News Today.

“We even found that the levels were increased before symptom onset and could predict subsequent development of clinical disease,” he added. “That could be important for future clinical trials aiming at evaluating novel therapies that might slow down or halt the disease progression before symptom onset.”

Other biomarkers of Parkinson’s disease

This is not the first biomarker to be found linked to Parkinson’s disease.

A study from October 2022 found that the shape of a group of proteins in cerebrospinal fluid could be a potential biomarker for Parkinson’s disease.

Research published in August 2023 looked at using genetic biomarkers to monitor the effectiveness of Parkinson’s therapies.

In July 2016, researchers published a study that found a biomarker for Parkinson’s disease in urine and cerebral-spinal fluid samples. And additional research in August 2016 uncovered a potential biomarker to help track disease progression in a noninvasive way.

“Parkinsonian disorders are often difficult to diagnose accurately based on clinical assessments alone, especially during early disease stages,” Dr. Hansson pointed out when asked why is it important to have biomarkers to help identify Parkinson’s disease.

“PET imaging of the dopaminergic neurons is often helpful, but it is expensive and requires a complex infrastructure,” he added. “Accurate fluid biomarkers, especially if they can be measured in blood, would be much more cost-effective and scalable.”

What are the symptoms of Parkinson’s disease? 

In a person with Parkinson’s, symptoms start off slowly and develop over time. They include:

• tremors in the hands or fingers
• loss of balance or coordination
• slowed movement
• muscle stiffness
• poor posture
• loss of smell
• sleeping issues
• constipation
• handwriting becomes smaller
• voice becomes softer and/or has a tremor
• mood changes
• difficulty chewing and/or swallowing
• dementia.

Although researchers are not entirely sure what causes Parkinson’s disease, they do know it is related to low levels of dopamine in the body, which is required to send messages to the area of the brain responsible for movement and coordination.

Scientists also believe that damaged nerve endings resulting in low norepinephrine levels may be to blame.

Risk factors for Parkinson’s disease include:

• genetics
• age — most people are diagnosed at age 60 or older
• gender — disease risk is twice as high in men as in women
• exposure to toxins
• past traumatic brain injury.

Detection of Parkinsonian diseases at preclinical stage

MNT also spoke with Dr. Sameea Husain, director of movement disorder neurology with Marcus Neuroscience Institute, part of Baptist Health South Florida, at Boca Raton Regional Hospital, about this study. Dr. Husain was not involved in the research.

She said the ability to detect preclinical stages in Lewy body dementia would be extremely beneficial for the families and caregivers to know in advance so that there could be planning for the future and perhaps even enrolment in research clinic trials aimed at Lewy body dementia patients.

Additionally, Dr. Husain said it would also increase diagnostic accuracy when trying to diagnose Parkinson’s or atypical Parkinsonian patients.

“As a neurologist, the holy grail is to be able to capture Lewy body, Parkinson’s disease, and atypical Parkinsonian patients as early as possible. This cerebrospinal fluid biomarker utilizing DOPA decarboxylase would help us be able to do that if there was even an inkling of a suspicion that this was the type of patient in front of us. If we could capture patients in the preclinical stages of disease, then the evidence-based mantra that early-treated patients have a better quality of life would stand the test of time.”

– Dr. Sameea Husain

“The next steps for me [in this research] would be to see this study magnified with more patient enrolment so that this type of test could show safety and efficacy and eventually come to the commercial market,” she added.

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