Early biological signs of Parkinson’s disease have been detected in blood years before symptoms appear, raising the prospect of earlier diagnosis and future treatment.
The findings suggest key disease processes leave measurable traces in blood for a limited time, creating a window for early detection. Blood tests could begin to be trialled in healthcare within five years.
Parkinson’s affects more than 10m people worldwide and, as populations age, that figure is expected to more than double by 2050. There is currently no cure and no established screening test for early-stage disease.
The research was led by scientists from Chalmers University of Technology in Sweden, working with colleagues at Oslo University Hospital in Norway.
Danish Anwer, a doctoral student and first author of the study, said: “By the time the motor symptoms of Parkinson’s disease appear, 50 to 80 per cent of the relevant brain cells are often already damaged or gone.
“The study is an important step towards facilitating early identification of the disease and counteracting its progression before it has gone this far.”
By the time movement-related symptoms such as tremor or stiffness develop, between 50 and 80 per cent of the brain cells affected by Parkinson’s are often already damaged or lost.
The study examined two biological processes thought to occur very early in Parkinson’s, sometimes up to 20 years before symptoms fully emerge. One involves DNA repair, the cell’s system for fixing genetic damage. The other is the cellular stress response, where cells temporarily pause normal activity to focus on protection and repair.
Using machine learning, the researchers identified a distinct pattern of gene activity linked to these processes in people at an early stage of Parkinson’s. The same pattern was not seen in healthy individuals or in patients who already had clear symptoms.
Annikka Polster, who led the study, said: “This means that we have found an important window of opportunity in which the disease can be detected before motor symptoms caused by nerve damage in the brain appear.
“The fact that these patterns only show at an early stage and are no longer activated when the disease has progressed further also makes it interesting to focus on the mechanisms to find future treatments.”
Polster added: “In our study, we highlighted biomarkers that likely reflect some of the early biology of the disease and showed they can be measured in blood.
“This paves the way for broad screening tests via blood samples: a cost-effective, easily accessible method.”
In the longer term, the team hopes the work could also support drug development aimed at slowing or preventing Parkinson’s.
Polster said: “If we can study the mechanisms as they happen, it could provide important keys to understanding how they can be stopped and which drugs might be effective.
“This may involve new drugs, but also drug repurposing, where we can use drugs developed for diseases other than Parkinson’s because the same gene activities or mechanisms are active.”
