Blood test could detect Parkinson’s disease 7 years before symptoms begin

LONDON — Parkinson’s disease, a devastating brain disorder affecting millions around the world, has long been a challenge to detect early on. By the time symptoms like tremors and stiffness show up, irreversible damage has already been done. But now, scientists from University College London have created a straightforward blood test that could identify Parkinson’s up to seven years before movement problems appear, paving the way for earlier treatment and better results.

The groundbreaking test, described in a recent Nature Communications paper, measures the amounts of just eight proteins in the blood.

Using artificial intelligence, the researchers discovered that the combined pattern of these proteins could accurately distinguish Parkinson’s patients from healthy people every single time. Even more impressively, the test flagged nearly eight out of every 10 individuals in the earliest stage of the disease before movement issues arise.

This progress builds on growing evidence that Parkinson’s, while mainly a brain disorder, also involves distinct changes in the rest of the body, especially related to inflammation. The eight-protein signature includes several markers of an overactive immune system and stress within cells, pointing to biological processes that go off course years before the disease’s hallmark brain changes cause neurons to die.

Methodology & Results

To develop the test, the scientists first cast a wide net, comparing blood samples from a small group of recently diagnosed Parkinson’s patients and healthy individuals. This revealed a number of proteins with differing levels between the two groups, hinting at the involvement of inflammation and cellular stress responses. The team then designed a targeted test to precisely measure the most promising of these proteins. They validated it in a larger group, including Parkinson’s patients, healthy controls, and, importantly, people with a sleep disorder called REM sleep behavior disorder (RBD), considered a key early warning sign of Parkinson’s. The test performed well, clearly separating Parkinson’s patients from healthy folks.

Next, the researchers used computer models to zero in on the most telling proteins, landing on a panel of just eight. A model based on only these eight could correctly identify Parkinson’s 100% of the time in the test group. Intriguingly, it also flagged about 80% of the “pre-motor” RBD group as having Parkinson’s-like changes, fitting with the fact that over 80% of such individuals eventually develop the disease.

To further put the test through its paces, the scientists applied it to samples collected over time from a separate group of 54 people with RBD. Remarkably, it classified nearly 80% as having a Parkinson’s-like protein signature up to seven years before any were diagnosed with the disease based on emerging movement symptoms. Though not perfect, it provides a strong foundation for a screening tool to identify high-risk individuals for early interventions.

Limitations

While tremendously encouraging, the study does have limitations. Diagnosis of RBD was based on sleep tests and neurological exams rather than brain autopsies, so it’s possible some participants had a different underlying condition. Additionally, RBD represents just one path to Parkinson’s. More work is needed to see if the protein signature holds up across different types of patients. Larger studies with more diverse groups of people will be key to validating the test for widespread screening.

Discussion & Takeaways

All in all, the study signifies concrete progress toward a long-sought aim in Parkinson’s research: a simple, affordable test to detect the disease early enough to intervene before substantial brain cell loss occurs. The fact that it homes in on inflammatory proteins also bolsters the growing idea that Parkinson’s is not just a brain condition but a body-wide disease with red flags that can be spotted in the blood. Figuring out how these inflammatory changes relate to, and perhaps even drive, the clumping of the culprit protein alpha-synuclein could unleash a whole new wave of targeted treatments to slow or halt the disease process.

The journey from a promising blood test to a widely used diagnostic and screening tool is a long one, requiring more validation and fine-tuning. But for the millions living with or at risk of Parkinson’s and their loved ones, studies like this one offer a much-needed glimmer of hope. A future when a routine blood draw could catch Parkinson’s in its earliest stages, allowing for a quick start of protective therapies, may not be as far-fetched as we once thought. While not a cure, early detection would be a pivotal first step in rewriting the Parkinson’s narrative from one of unstoppable decline to one of proactive care and better quality of life.

“As new therapies become available to treat Parkinson’s, we need to diagnose patients before they have developed the symptoms. We cannot regrow our brain cells and therefore we need to protect those that we have,” says Professor Kevin Mills from UCL Great Ormond Street Institute of Child Health in a media release.

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