Analog molecule could throw off Parkinson’s diagnosis

Monitoring dopamine activity may not be as ideal as previously thought for patients suspected of having Parkinson’s disease. Researchers at Washington State University have found an “imposter molecule” that could be mistaken for dopamine in tests that look for low-levels of the neurostransmitter as a sign of the neurodegenerative disease, the university announced Wednesday.

Herbert H. Hill, PhD, a professor of chemistry at Washington State University in Pullman, and his team of scientists collaborated with researchers at Texas A&M University in College Station, Texas, to smoke out the molecule. With advanced ion mobility mass spectrometry (IMMS) and animal models, the researchers uncovered the mysterious compound that could be throwing off diagnostic dopamine tests for disorders like Parkinson’s. The hallmark low-levels of dopamine in cases of Parkinson's could be kept hidden in the presence of dopamine-like molecules leading to false negatives, keeping patients with the disease from receiving essential treatment.

A comparison of normal brain tissue and a preclinical model of Parkinson’s disease was analyzed using an ion mobility technique that gauges the mobility rates of molecules moving through a cylinder. This type of mass spectrometry allows scientists to take down the signatures of individual molecules being tested.

“We get a complex array of mass and mobility information that was never before possible,” said Hill, in the WSU announcement.

The researchers were able to tell dopamine apart from its doppelganger because actual dopamine weighs the same, but does not travel as quickly or have as high a mobility rate as its imposter.

Hill’s research is expanding to map the entire metabolome. He and his collaborators can evaluate thousands of compounds in a tiny blood sample and thereby assess important biomarkers of disease. There may be nine or more metabolites signaling Parkinson’s alone that could one day be used for advanced diagnostic tests.

In addition to Parkinson’s, Hill and his team are also looking to map metabolites involved in diabetes and colorectal cancer.