World’s First Biomarker Can Diagnose Parkinson's Disease from Blood Serum Samples

 Currently, there is no way of completely curing Parkinson’s disease. Therefore, early detection is vital in order to stop its progression. Currently, various biomarkers are in development that can be used to evaluate diseases. These biomarkers can detect the presence of a disease, as well as monitor its progress and the effectiveness of treatment. In a world-first, researchers have succeeded in developing a biomarker that can be used to easily and inexpensively assess Parkinson’s disease.
The drug metabolizing enzyme Cytochrome P450 not only metabolizes drugs but also serves as a catalyst for the oxidation of various substances. It is known that the expression of P450 inside the body changes with the onset of various diseases. This change in P450 expression is thought to affect the quantity and quality of metabolites in the patient’s body that are related to P450. A group of researchers at Kobe University (Kobe, Japan) and Hiroshima University (Higashihiroshima, Japan) had previously come up with a ‘P450 inhibition assay’ to easily detect changes in the quality and quantity of P450-related metabolites brought on by the onset of disease. This time, they have become the first in the world to successfully apply this method to Parkinson’s disease diagnosis.
In the developed assay, 12 different human P450s are each mixed with a serum sample and a fluorescent substrate to cause a reaction. There are differences in quantity and quality of P450-related metabolites in the sera from healthy individuals and patients. These serum metabolites inhibit the P450-mediated oxidation of the fluorescent substrate. By looking at the inhibition rate related to disease onset-mediated alterations in certain P450s, it is possible to discriminate sera samples from an individual with a specific disease and a healthy subject. P450 reacts with the fluorescent substrate to generate a fluorescent substance when the assay is performed on the sera from healthy individuals. However, the reaction is different when the assay is conducted on the sera from patients and thus the obtained fluorescent values change. In this way, the ‘P450 fluorescent inhibition assay’ can be used to determine whether or not a disease is present by detecting these changes. It is a new liquid biopsy technique that did not exist until now.
The current study on Parkinson’s disease utilized the ‘P450 inhibition assay’ that was independently developed by the research group. Specifically, they carried out the assay on Parkinson’s disease model rats and on human patients with the disease (as well as patients with other neurodegenerative and inflammatory diseases) to evaluate whether or not the assay could be used for Parkinson’s disease diagnosis. The results revealed that healthy individuals and individuals with Parkinson’s disease could be classified at an accuracy rate of 85~88% for both the model rat and human subjects.
Thus, the results of the study have shown that the ‘P450 inhibition assay’ has the potential to be applied to the diagnosis of Parkinson’s disease. This assay only requires mere 30μ of serum and is a comparatively inexpensive testing method and therefore, will benefit Parkinson’s disease screening. Next, the researchers will conduct clinical performance evaluations on a larger scale, with the aim of working towards the implementation of this testing method.