First-of-a-kind blood test paves way for early Parkinson's diagnosis
With no way of completely curing the condition, earlier diagnosis of Parkinson's disease can have profound impacts on treatment options and a patient's quality of life. Scientists are making inroads when it comes to picking up the tell-tale signs of the disease's onset, and a new first-of-a-kind study has demonstrated how these might be revealed through an inexpensive blood test that has shown a high degree of accuracy in early trials.
Doctors will currently diagnose Parkinson's disease by making an assessment of a patient's motor symptoms, medical history and physical and mental well-being, but symptoms can be hard to distinguish from other neurological conditions. And because early and accurate diagnosis creates a larger window for lifestyle interventions such as exercise and treatment options such as the drug levodopa, which are more effective in its early stages, there is considerable interest in improving on current methods.
Biomarkers that show up in the blood or even skin are seen as highly promising tools that may offer clear and early evidence of the onset of Parkinson's, and scientists are making some exciting inroads in the development of tests designed to detect them. One we looked at back in 2016, for example, focused on detecting abnormal metabolism of blood cells in Parkinson's patients, while another in 2020 showed that sufferers had shorter telomeres, structures at the end of chromosomes, which could be revealed via blood samples.
The latest breakthrough in this area also focuses on the blood, but on a different marker in a superfamily of enzymes called Cytochrome P450. These form a vital metabolic system that evolved to help organisms, including humans, safely metabolize chemicals and oxidize fatty acids, among other important functions. The expression of P450 enzymes is known to change in the face of inflammation brought on by cancer, cardiovascular disease and diabetes, driving alterations in the related metabolites in a patient's body.
Scientists at Japan's Kobe University had previously developed a "P450 inhibition assay," a kind of test that could detect these altered metabolites in blood serum samples. This had proven effective as a way of detecting ulcerative colitis and diabetes in mice, giving the team the impression it could work for Parkinson's disease too, a disease also associated with inflammation.
The scientists conducted experiments on blood serum taken from human patients and rat models of Parkinson's disease, with the assay relying on a chemical reaction that involves the oxidation of a fluorescent substrate. The altered metabolites in the serum taken from diseased patients and rodents inhibit this process, and this differing rate of oxidation provides the point of difference that enables them to be distinguished from healthy patients.
This is the first study to show that a P450 assay can be applied to diagnosis of Parkinson's disease, with the team reporting an accuracy of 85 to 88 percent for both the human and rat subjects. The hope is that it can lead to a cheap and easy way to screen for the disease in its early stages, but also that it can further our understanding of the molecular mechanisms behind it and perhaps lead to new treatments. The team is now setting its sights on larger trials to assess the technique's clinical performance.
The research was published in the journal Scientific Reports.