July 23, 2024

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Early PET Detection of Parkinson’s and Lewy Body Dementia Risk

Early PET Detection of Parkinson’s and Lewy Body Dementia Risk



Early PET Detection of Parkinson’s and Lewy Body Dementia Risk

PET Scans for the Heart: Predictive Indicators for Parkinson’s Disease and Lewy Body Dementia Detected Years Before Symptoms.

A study conducted by researchers from the National Institutes of Health (NIH) in the United States has revealed that positron emission tomography (PET) scans of the heart can predict the likelihood of developing Parkinson’s disease or Lewy body dementia.

Led by Dr. Goldstein, the study analyzed the levels of norepinephrine, a neurotransmitter, in the hearts of individuals at risk for Parkinson’s disease, offering a potential method for early detection and intervention in these neurodegenerative diseases.

Biomarkers indicating a deficiency in heart norepinephrine could aid in detecting Lewy body diseases before symptoms manifest.

Early PET Detection of Parkinson's and Lewy Body Dementia Risk

PET scans of the heart and brain of a Parkinson’s disease patient support a “body first” development process. The top pair of positron emission computed tomography scans shows low 18F-dopamine-derived radioactivity in the heart (right) and normal 13N-ammonia positron emission computed tomography (left), which is the case Occurs before the loss of dopamine-producing neurons and the onset of symptoms. Image source: NINDS Goldstein Laboratory

In a small-scale study at the NIH Clinical Center, researchers found that PET scans of the heart could identify individuals in high-risk groups for Parkinson’s disease or Lewy body dementia.

Published in the Journal of Clinical Research and led by scientists from the National Institute of Neurological Disorders and Stroke (NINDS), a subsidiary of the NIH, the study may advance efforts to detect early changes leading to Parkinson’s disease and Lewy body dementia.

PET Scans as Predictive Tools

The research team conducted heart PET scans on 34 individuals with risk factors for Parkinson’s disease to understand the levels of the neurotransmitter norepinephrine. They observed that the scan results could differentiate individuals who later received diagnoses of Parkinson’s disease or Lewy body dementia—both diseases caused by abnormal deposits of the protein alpha-synuclein, forming clusters known as Lewy bodies in the brain. The study took place at the NIH Clinical Center, the sole location conducting 18F-dopamine PET scans.

Norepinephrine, derived from dopamine, is lacking in the brains of Parkinson’s disease patients. Dr. David S. Goldstein, the chief researcher at NINDS, previously demonstrated severe deficiency of heart norepinephrine in Lewy body disease patients, where norepinephrine is typically released by nerves supplying the heart.

In this study, Dr. Goldstein’s research team found that individuals in the high-risk group with lower levels of 18F-dopamine-derived radioactivity in the heart, compared to those with the same risk factors but normal radioactivity, had a higher probability of developing Parkinson’s disease or Lewy body dementia during long-term follow-ups. PET scans utilize radioactive tracers to observe the metabolism or biochemical processes of organs in the body.

Dr. Goldstein remarked, “Think of the scan results like frames in a movie. That first eight-minute frame of assessment was enough to identify who might develop central Lewy body disease several years later.”

In the study, 34 individuals at risk of Parkinson’s disease received heart 18F-dopamine PET scans every 18 months for approximately 7.5 years or until diagnosed with Parkinson’s disease. These individuals had three or more Parkinson’s disease risk factors, including a family history of Parkinson’s disease, common anosmia (loss of smell) seen in Parkinson’s patients, a sleep disorder involving dream enactment behavior, and orthostatic intolerance symptoms such as dizziness when standing.

Among the nine individuals with initially low heart 18F-dopamine-derived radioactivity, eight were later diagnosed with Parkinson’s disease or Lewy body dementia. In the 11 participants with initially normal radioactivity, only one developed central Lewy body disease. All nine patients with Lewy body disease had low radioactivity either before or at the time of diagnosis.

Impact on Synuclein Diseases

This study supports the idea that synuclein diseases, such as Parkinson’s disease and Lewy body dementia, affect the nerves of the autonomic nervous system, responsible for regulating bodily functions like heart rate and blood pressure. Dr. Goldstein and his team’s research suggests that synuclein protein aggregates occur in the nerves leading to gastrointestinal organs, skin, and glands in both diseases.

“We believe that in many cases of Parkinson’s disease and Lewy body dementia, the disease process doesn’t actually begin in the brain. Through autonomic nervous system abnormalities, these processes eventually make their way into the brain,” Dr. Goldstein explained. “The loss of norepinephrine in the heart predicts and precedes the loss of dopamine in the brain in Lewy body diseases.”

Achieving Early Detection and Prevention

Identifying biomarkers for diseases before symptoms appear (preclinical stage) is crucial for testing early intervention measures. Parkinson’s disease only manifests noticeable motor symptoms once the neurons in the brain controlling movement, which produce dopamine, are severely damaged or lost.

Dr. Goldstein stated, “By the time symptoms appear, much of the damage has already been done. The hope is to detect the disease as early as possible. If we can salvage dopamine terminals that are already affected but not yet dead, it might be possible to extend the time before patients show symptoms.”

Using positron emission tomography scans to identify preclinical Lewy body disease patients could facilitate testing lifestyle adjustments, dietary supplements, or medications as preventive measures.


What is PET scan?

 

A Positron Emission Tomography (PET) scan is a medical imaging technique that allows physicians to observe metabolic and biochemical processes in the body.

During a PET scan, a small amount of a radioactive substance, known as a tracer, is introduced into the body. As the tracer travels through the body, it emits positrons (positively charged particles).

When a positron encounters an electron, they annihilate each other, producing gamma rays.

The PET scanner detects these gamma rays and creates detailed three-dimensional images that illustrate the distribution and activity of the tracer in the organs and tissues.

PET scans are commonly used in various medical fields, including oncology, neurology, and cardiology, to help diagnose and monitor diseases.

Early PET Detection of Parkinson’s and Lewy Body Dementia Risk

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