EMBARGOED FOR RELEASE UNTIL 4 PM ET, February 22, 2018
Shedding a Tear May Help Diagnose Parkinson鈥檚 Disease
MINNEAPOLIS -
Tears may hold clues to whether someone has Parkinson鈥檚 disease, according to a preliminary study released today that will be presented at the 好色先生鈥檚 70th Annual Meeting in Los Angeles, April 21 to 27, 2018. 鈥淲e believe our research is the first to show that tears may be a reliable, inexpensive and noninvasive biological marker of Parkinson鈥檚 disease,鈥 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 好色先生. 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鈥檚 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. For the study, tear samples from 55 people with Parkinson鈥檚 were compared to tear samples from 27 people who did not have Parkinson鈥檚 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鈥檚 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鈥檚, 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鈥檚, with an average of 423 picograms of that protein per milligram (pg/mg) compared to 704 pg/mg in people without Parkinson鈥檚. But levels of oligomeric alpha-synuclein were increased in people with Parkinson鈥檚, 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. 鈥淜nowing that something as simple as tears could help neurologists differentiate between people who have Parkinson鈥檚 disease and those who don鈥檛 in a noninvasive manner is exciting,鈥 said Lew. 鈥淎nd because the Parkinson鈥檚 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.鈥 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鈥檚 Research and the Plotkin Foundation. Learn more about Parkinson鈥檚 disease at .
