FM AUGUST 2018 ISSUE1 - digital edition

diagnostics
Parkinson’s
screening
through
tear drops?
There could be a reliable,
inexpensive, and non-invasive
way to diagnose Parkinson’s
disease—a tear protein
A
study 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 - FM
42 / FUTURE MEDICINE / AUGUST 2018