Early Parkinson's Diagnosis Moves Closer with New Protein Test

There is currently no definitive test for Parkinson's and the disease is normally diagnosed through assessment of the patient's medical history, a medical examination, and physical and neurological tests, but this can take years.

A novel real-time quaking-induced conversion (RT-QuIC)-based assay has been to detect alpha-synuclein aggregation in brain and cerebrospinal fluid from dementia with Lewy bodies and Parkinson's disease patients.

Scientists at the University of Edinburgh (UK) applied the RT-QuIC test to 20 samples of cerebrospinal fluid (CSF) taken from patients with Parkinson's disease, alongside samples of 15 healthy controls. CSF was drawn from patients by lumbar puncture and samples with visible red color were excluded to avoid blood contamination. A total quantity of 15 mL of CSF was collected in 20 mL polypropylene tubes and samples were stored on ice until centrifuged for 5 min at 1300g at 4 °C to remove cellular components.

Frontal cortex tissue was taken from patients with Alzheimer’s disease (AD), sporadic Creutzfeldt–Jakob disease (sCJD), and diffuses Lewy body dementia (DLB). Real-time quaking induced aggregation for alpha-synuclein were carried out and incubated in a BMG OPTIMA FLUOstar plate reader (BMG LABTECH, Cary, NC, USA) at 30 °C for 120 hours with intermittent shaking cycles: double orbital with one minute shake (200 rpm), 14 minutes rest. Thioflavin (ThT) fluorescence measurements (450 nm excitation and 480 nm emission) were taken every 15 minutes.

The team found the test was able to identify 19 out of 20 of samples with 95% accuracy and 100% specificity. It was also able to detect buildup of the protein in three spinal fluid samples of individuals at high risk for Parkinson's. The team also applied the test to samples of patients with Lewy body dementia. Compared with control samples, the test was able to detect the disease with 92% accuracy and 100% specificity.

Alison J. Green, PhD, the lead investigator said, “We have already used this technique to develop an accurate test for Creutzfeldt Jacob Disease, another neurodegenerative condition. We hope that with further refinement, our approach will help to improve diagnosis for Parkinson’s patients. “We are also interested in whether the test could be used to identify people with Parkinson’s and Lewy body dementia in the early stages of their illness. These people could then be given the opportunity to take part in trials of new medicines that may slow, or stop, the progression of disease.” The study was published on August 28, 2016, in the journal Annals of Clinical and Translational Neurology.

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