News • New test

Tears don't lie – they may even help diagnose Parkinson’s

Tears may hold clues to whether someone has Parkinson’s disease, according to a preliminary study released that will be presented at the American Academy of Neurology’s 70th Annual Meeting in Los Angeles, April 21 to 27, 2018.

Photo
Source: Pixabay/cherylholt

“We believe our research is the first to show that tears may be a reliable, inexpensive and noninvasive biological marker of Parkinson’s disease,” said study author Mark Lew, MD, of the Keck School of Medicine of the University of Southern California in Los Angeles and a Fellow of the American Academy of Neurology. Lew says the research team investigated tears because they contain various proteins produced by the secretory cells of the tear gland, which is stimulated by nerves to secrete these proteins into tears. Because Parkinson’s can affect nerve function outside of the brain, the research team hypothesized that any change in nerve function may be seen in the protein levels in tears.

Source: Pixabay/Bella67

Because the Parkinson’s disease process can begin years or decades before symptoms appear, a biological marker like this could be useful in diagnosing, or even treating, the disease earlier

Mark Lew

For the study, tear samples from 55 people with Parkinson’s were compared to tear samples from 27 people who did not have Parkinson’s but who were the same age and gender. Tears were analyzed for the levels of four proteins. Researchers found differences in the levels of a particular protein, alpha-synuclein, in the tears of people with Parkinson’s compared to controls. Additionally, levels of another form of alpha-synuclein, oligomeric alpha-synuclein, which is alpha-synuclein that has formed aggregates that are implicated in nerve damage in Parkinson’s, were also significantly different compared to controls. It is also possible that the tear gland secretory cells themselves produce these different forms of alpha-synuclein that can be directly secreted into tears.

Total levels of alpha-synuclein were decreased in people with Parkinson’s, with an average of 423 picograms of that protein per milligram (pg/mg) compared to 704 pg/mg in people without Parkinson’s. But levels of oligomeric alpha-synuclein were increased in people with Parkinson’s, with an average of 1.45 nanograms per milligram of tear protein (ng/mg) compared to 0.27 ng/mg in people without the disease. A picogram is 1,000 times smaller than a nanogram. “Knowing that something as simple as tears could help neurologists differentiate between people who have Parkinson’s disease and those who don’t in a noninvasive manner is exciting,” said Lew. “And because the Parkinson’s disease process can begin years or decades before symptoms appear, a biological marker like this could be useful in diagnosing, or even treating, the disease earlier.” 

More research now needs to be done in larger groups of people to investigate whether these protein changes can be detected in tears in the earliest stages of the disease, before symptoms start.

The study was supported by The Michael J. Fox Foundation for Parkinson’s Research and the Plotkin Foundation.


Source: American Academy of Neurology (AAN)

23.02.2018

More on the subject:

Related articles

Photo

News • Taxane-induced peripheral neuropathy

New tool predicts nerve damage after breast cancer chemotherapy

Researchers have developed a tool that can predict the risk level for side effects in the nervous system of women treated for breast cancer using taxanes. This could help adapt treatment.

Photo

News • Vascular and Neurosurgery

New procedure to prevent phantom pain after limb amputation

6 out of 10 people develop pain after a limb amputation. Researchers now investigate whether a preventive, relatively simple nerve surgery can prevent patients from experiencing this pain.

Photo

News • Biomarkers enhance early detection

Parkinson's: blood test predicts disease up to seven years before symptoms

A novel blood test shows promise to predict Parkinson's disease in risk patients up to seven years before the typical motor symptoms appear.

Related products

Subscribe to Newsletter