Blood test reveals early signs of Parkinson’s disease

Scientists have discovered a biomarker that could be used to identify Parkinson’s before extensive brain damage has occurred. The finding, by a team at Chalmers University of Technology, Sweden, and Oslo University Hospital, Norway, paves the way for a new test and for earlier treatment.

The biological processes underlying the initial stages of the disease leave measurable traces in the blood, but only for a limited period. The discovery reveals a window of opportunity that could be crucial for future intervention.

Parkinson’s affects over 10 million people globally. As the world’s population grows older, this number is expected to more than double by 2050. At present, there is neither an effective cure nor an established screening method for detecting this chronic neurological disorder before it has caused significant damage to the brain.

‘By the time the motor symptoms of Parkinson’s disease appear, 50-80 per cent of the relevant brain cells are often already damaged or gone,’ says Danish Anwer, a doctoral student at the Department of Life Sciences at Chalmers. ‘The study is an important step towards facilitating early identification of the disease and counteracting its progression before it has gone this far.’

In the paper, published in npj Parkinson’s Disease, researchers focus on cellular mechanisms thought to be involved in the very early phase of the disease. This initial stage can last up to 20 years in Parkinson’s patients before motor symptoms are fully developed.

The researchers used machine learning and other techniques to discover a pattern of distinct gene activities linked to DNA repair and stress response in patients in the early phase of Parkinson’s. This pattern was not found in either healthy individuals or diagnosed patients who already had symptoms.

‘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,’ says Annikka Polster, Assistant Professor at the Department of Life Sciences at Chalmers, who led the study. ‘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.’

In the intense global research into Parkinson’s disease, several other biological indicators of the early stage of the disease have been examined, including those linked to brain imaging or brain fluid analyses. However, validated tests suitable for widespread screening to detect the disease before symptoms appear are not yet available.

‘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,’ says Polster.

The researchers are currently studying the mechanisms activated in the early stage of the disease with a view to developing a routine test within five years. In the longer term, it is hoped that the research will also contribute to the development of drugs to prevent or treat the disease.