Using Heart PET Scans to Foresee Parkinson’s and Lewy Body Dementia Before Clinical Symptoms Manifest

Researchers at the NIH have discovered that heart PET scans can be used to foresee the development of Parkinson’s disease and Lewy body dementia. The study, led by Dr. Goldstein, focuses on evaluating cardiac norepinephrine levels in individuals predisposed to Parkinson’s, offering an innovative approach for the early detection and treatment of these neurodegenerative disorders.

The presence of a biomarker indicating a lack of norepinephrine in the heart could be crucial in identifying Lewy body diseases before the onset of symptoms.

In a preliminary study conducted by the National Institutes of Health, heart positron emission tomography (PET) scans were found to potentially identify individuals at risk of developing Parkinson’s disease or Lewy body dementia. Published in the Journal of Clinical Investigation, this research, spearheaded by the National Institute of Neurological Disorders and Stroke (NINDS) of the NIH, might contribute to the early detection of the initial changes that later result in Parkinson’s disease and Lewy body dementia.

“Consider the scans as segments of a film. A single frame at the 8-minute mark of the initial assessment can pinpoint those who may eventually develop central Lewy body disease in the future,” said David S. Goldstein, M.D., Ph.D.

Predictive Role of PET Scans

PET scans of the heart were conducted on 34 individuals with risk factors for Parkinson’s disease. These scans provided insights into the levels of the neurotransmitter norepinephrine. The findings indicated that these scans could differentiate between those who would later be diagnosed with Parkinson’s or Lewy body dementia—both conditions are characterized by abnormal accumulation of the protein alpha-synuclein, forming aggregates known as Lewy bodies. This study was undertaken at the NIH Clinical Center, the only place offering 18F-dopamine PET scanning.

Understanding the Significance of Norepinephrine

Norepinephrine, a derivative of dopamine, is found to be deficient in individuals with Parkinson’s disease. Previous research by David S. Goldstein, M.D., Ph.D., Principal Investigator at NINDS, showed that patients with Lewy body diseases experience a substantial reduction of cardiac norepinephrine, typically secreted by nerves serving the heart.

Study Methodology and Key Discoveries

Dr. Goldstein’s team observed that participants at risk, with lower levels of 18F-dopamine-derived radioactivity in the heart, were more likely to develop Parkinson’s or Lewy body dementia during extended follow-up periods. This was in contrast to those with similar risk factors but normal radioactivity levels. PET scans operate by using radioactive tracers to visualize metabolic or biochemical processes in body organs.

A participant who developed Parkinson’s disease had heart and brain PET scans showing low 18F-dopamine-derived radioactivity in the heart and a normal 13N-ammonia PET scan. This indicated a “body first” progression, where the loss of dopamine-producing neurons and symptom manifestation followed. Credit: Goldstein lab, NINDS.

“Think of the scans as snapshots of a film,” Dr. Goldstein explained. “A snapshot at the 8-minute mark of the first assessment is sufficient to identify those likely to develop central Lewy body disease years later.”

In the study, 34 individuals at risk for Parkinson’s underwent heart 18F-dopamine PET scans every 18 months for up to about 7.5 years or until diagnosis. The risk factors included family history, loss of smell, dream enactment behavior, and symptoms of orthostatic intolerance like dizziness upon standing.

Out of nine participants with low cardiac 18F-dopamine-derived radioactivity in their initial scan, eight were later diagnosed with Parkinson’s or Lewy body dementia. In contrast, only one out of eleven with normal initial radioactivity developed a central Lewy body disease. All nine participants who developed a Lewy body disease had low radioactivity either before or at the time of diagnosis.

Implications for Synuclein Disorders

This study suggests that synuclein disorders like Parkinson’s disease and Lewy body dementia impact the autonomic nervous system, which regulates involuntary bodily functions such as heart rate and blood pressure. Dr. Goldstein’s and others’ work indicates that synuclein aggregation occurs in nerves connected to gastrointestinal organs, skin, and glands in both conditions.

“We believe that in many Parkinson’s and dementia with Lewy bodies cases, the disease processes start outside the brain. They initially affect the autonomic system before eventually reaching the brain,” Dr. Goldstein noted. “The decline of norepinephrine in the heart is an early indicator and precedes the loss of dopamine in the brain in Lewy body diseases.”

Advancing Early Detection and Prevention

Identifying biomarkers for early disease detection, or the preclinical period, is crucial for testing early interventions. The visible motor symptoms of Parkinson’s only appear after significant damage or loss of dopamine-producing

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More about Heart PET Scans Parkinson’s Prediction

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• PET Scans in Medical Diagnosis