Wednesday, November 22, 2023

PET Scans May Predict Parkinson’s Disease, Lewy Body Dementia in At-Risk Individuals

 

With your risk of Parkinsons post stroke, your competent doctor should be ready to apply this on you. Or don't you have a competent doctor?

Parkinson’s Disease May Have Link to Stroke March 2017

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PET Scans May Predict Parkinson’s Disease, Lewy Body Dementia in At-Risk Individuals

Positron emission tomography (PET) scans of the heart may identify people who will go on to develop Parkinson’s disease or Lewy body dementia among those at-risk for these diseases, according to a study published in the Journal of Clinical Investigation.

For the study, David S. Goldstein, MD, National Institute

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of Neurological Disorders and Stroke, part of the National Institutes of Health, Bethesda, Maryland, and colleagues conducted 18F-dopamine PET scans of the heart in 34 people with Parkinson’s disease risk factors to gain insight into levels of the neurotransmitter norepinephrine. 

Norepinephrine is derived from dopamine, which is deficient in the brains of people with Parkinson’s disease. Earlier work from Dr. Goldstein demonstrated that people with Lewy body diseases had severe depletion of cardiac norepinephrine, which is normally released by the nerves that supply the heart.

In the current study, at-risk individuals with low 18F-dopamine-derived radioactivity in the heart were highly likely to develop Parkinson’s or Lewy body dementia during long-term follow-up, compared with individuals with the same risk factors but with normal radioactivity. 

The patients in the study had cardiac 18F-dopamine PET scans every 18 months for up to about 7.5 years or until they were diagnosed with the disease. Participants had ≥3 Parkinson’s risk factors, which included a family history of the disease, loss of sense of smell, dream enactment behaviour, and symptoms of orthostatic intolerance.

Of the 9 individuals with low cardiac 18F-dopamine-derived radioactivity at their first scan, 8 were diagnosed later with Parkinson’s or Lewy body dementia. Only 1 of 11 participants with normal initial radioactivity developed a central Lewy body disease. All 9 participants who developed a Lewy body disease had low radioactivity before or at the time of diagnosis.  

The study supports the view that synuclein disorders such as Parkinson’s disease and Lewy body dementia affect the nerves of the autonomic nervous system.

“We think that in many cases of Parkinson’s and dementia with Lewy bodies the disease processes don’t actually begin in the brain,” said Dr. Goldstein. “Through autonomic abnormalities the processes eventually make their way to the brain. The loss of norepinephrine in the heart predicts and precedes the loss of dopamine in the brain in Lewy body diseases.”  

Finding biomarkers that could help detect diseases before symptoms begin is critical for testing early interventions. The visible motor symptoms of Parkinson’s occur only after substantial damage or loss of dopamine-producing neurons in regions of the brain that control movement.

“Once symptoms begin, most of the damage has already been done,” said Dr. Goldstein. “You want to be able to detect the disease early on. If you could salvage the dopamine terminals that are sick but not yet dead, then you might be able to prolong the time before the person shows symptoms.”  

Using the PET scans to identify people with preclinical Lewy body diseases could enable testing of preventative approaches such as lifestyle modifications, dietary supplements, or medications.

Reference: https://www.jci.org/articles/view/172460

SOURCE: National Institutes of Health

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