Researchers identify biomarker for depression, antidepressant response


Date:
January 3, 2022
Source:
University of Illinois at Chicago
Summary:
Researchers have identified a biomarker in human platelets that
tracks the extent of depression.



FULL STORY ========================================================================== Researchers are one step closer to developing a blood test that provides
a simple biochemical hallmark for depression and reveals the efficacy
of drug therapy in individual patients.


========================================================================== Published in a new proof of concept study, researchers led by Mark
Rasenick, University of Illinois Chicago distinguished professor of
physiology and biophysics and psychiatry, have identified a biomarker
in human platelets that tracks the extent of depression.

The research builds off of previous studies by several investigators that
have shown in humans and animal models that depression is consistent with decreased adenylyl cyclase -- a small molecule inside the cell that is
made in response to neurotransmitters such as serotonin and epinephrine.

"When you are depressed, adenylyl cyclase is low. The reason adenylyl
cyclase is attenuated is that the intermediary protein that allows the neurotransmitter to make the adenylyl cyclase, Gs alpha, is stuck in a cholesterol-rich matrix of the membrane -- a lipid raft -- where they
don't work very well," Rasenick said.

The new study, "A Novel Peripheral Biomarker for Depression and
Antidepressant Response," published in Molecular Psychiatry, has
identified the cellular biomarker for translocation of Gs alpha from
lipid rafts. The biomarker can be identified through a blood test.

"What we have developed is a test that can not only indicate the presence
of depression but it can also indicate therapeutic response with a
single biomarker, and that is something that has not existed to date,"
said Rasenick, who is also a research career scientist at Jesse Brown
VA Medical Center.



==========================================================================
The researchers hypothesize they will be able to use this blood test to determine if antidepressant therapies are working, perhaps as soon as one
week after beginning treatment. Previous research has shown that when
patients showed improvement in their depression symptoms, the Gs alpha
was out of the lipid raft. However, in patients who took antidepressants
but showed no improvement in their symptoms, the Gs alpha was still stuck
in the raft - - meaning simply having antidepressants in the bloodstream
was not good enough to improve symptoms.

A blood test may be able to show whether or not the Gs alpha was out of
the lipid raft after one week.

"Because platelets turn over in one week, you would see a change in
people who were going to get better. You'd be able to see the biomarker
that should presage successful treatment," Rasenick said.

Currently, patients and their physicians have to wait several weeks,
sometimes months, to determine if antidepressants are working, and when
it is determined they aren't working, different therapies are tried.

"About 30% of people don't get better -- their depression doesn't resolve.

Perhaps, failure begets failure and both doctors and patients make
the assumption that nothing is going to work," Rasenick said. "Most
depression is diagnosed in primary care doctor's offices where they
don't have sophisticated screening. With this test, a doctor could say,
'Gee, they look like they are depressed, but their blood doesn't tell
us they are. So, maybe we need to re- examine this.'" Working with his company, Pax Neuroscience, Rasenick aims to develop the screening test
after further research.

This research was supported by the National Institutes of Health
(R43MH097370, R41MH113398) and U.S. Department of Veterans Affairs
(BX00149).

Additional researchers are Jeffrey Schappi, Athanasia Koutsouris and Runa Bhaumik, all of UIC; Steven Targum of Signant Health, Mark Rapaport of
the University of Utah, and Natalie Rasgon of Stanford University.

special promotion Explore the latest scientific research on sleep and
dreams in this free online course from New Scientist -- Sign_up_now_>>> academy.newscientist.com/courses/science-of-sleep-and-dreams ========================================================================== Story Source: Materials provided by
University_of_Illinois_at_Chicago. Note: Content may be edited for style
and length.


========================================================================== Journal Reference:
1. Steven D. Targum, Jeffrey Schappi, Athanasia Koutsouris, Runa
Bhaumik,
Mark H. Rapaport, Natalie Rasgon, Mark M. Rasenick. A
novel peripheral biomarker for depression and
antidepressant response. Molecular Psychiatry, 2022; DOI:
10.1038/s41380-021-01399-1 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2022/01/220103121528.htm
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