There could be a reliable, inexpensive, and non-invasive way to diagnose Parkinson’s disease—a tear protein
Astudy led by the University of Southern California (USC) in Los Angeles claims that Parkinson’s disease can be diagnosed non-invasively by analysing certain biological markers found in tears.
Researchers found different levels of a protein linked to the degenerative disease in the tear samples from individuals with Parkinson’s disease than those who did not have it.
Besides destroying brain cells that produce dopamine, evidence suggests that Parkinson’s kills cells that create another chemical messenger called norepinephrine, which helps to regulate many automatic functions in the body. This might explain why some of the symptoms are not related to movement.
It has been discovered that toxic protein deposits known as Lewy bodies are often present in many brain cells of people with Parkinson’s. These deposits contain clusters of proteins that have not folded correctly. Alpha-synuclein, an oligomeric form of the protein, is a key component of Lewy bodies.
Study author Mark F. Lew, who is a professor of clinical neurology in USC’s Keck School of Medicine, and colleagues believed that evidence of marker proteins could be present in tears since Parkinson’s influences nerve function that lies outside the brain.
Comparing tear samples taken from 55 individuals diagnosed with Parkinson’s with those of 27 who did not have the disease, they found that total alpha-synuclein was lower in the tears taken from the Parkinson’s disease group than those of the healthy group. The average levels were 423 and 704 picograms per milligram, respectively.
The oligomeric form of alpha-synuclein, however, was higher in the Parkinson’s disease group than in the healthy group; their averages were 1.45 and 0.27 nanograms per milligram of tear protein, respectively.
Researchers feel larger studies involving larger groups are needed to investigate whether the differences in alpha-synuclein are present in tears in the early stages of Parkinson’s. Also, still a lot of work needs to be done to confirm whether measuring this biological marker in tears is a viable diagnostic for Parkinson’s disease.