Antidepressants Benefit Heart Health?
April 28, 2010
(Ivanhoe Newswire) -- A class of
antidepressants known as selective serotonin reuptake inhibitors (SSRIs) may
boost cardiovascular health by affecting the way platelets -- small blood
cells involved in clotting -- clump together.
Researchers at the Loyola University Medical
Center in Maywood, Ill. found that platelets were slower to clump together
in participants who were taking an SSRI to treat depression. As depression
is associated with an increased risk of cardiovascular disease, this finding
could indicate a beneficial side effect for people who take SSRIs to treat
depression, study author Evangelos Litinas, MD, Research Associate in the
Center's Pathology Department, was quoted as saying.
Neurotransmitters, like serotonin, are
messages sent across the gap between nerve cells in the brain called the
synapse. The cell sending the message, called the pre-synaptic cell,
releases serotonin into the synapse. Either the serotonin is taken in by the
receiving, post-synaptic cell, or it can be taken back by the pre-synaptic
In a depressed patient, the post-synaptic cell
doesn't take in enough serotonin and the message gets lost. To treat the
depression, SSRIs inhibit the ability of the pre-synaptic cell to reuptake
the serotonin, leaving the message in the synapse longer and giving the
post-synaptic cell a better chance of receiving the serotonin.
This blocking activity of SSRIs may have an
effect on other cells in the body that require serotonin uptake. Platelets,
which are involved in blood clotting, absorb serotonin only once and use it
to activate in response to injury. This kind of platelet activation also
occurs when blood vessel walls become inflamed in atherosclerosis or
"hardening of the arteries."
Once activated, the platelets release the
contents of small packages that they carry called delta granules. These
packages contain various molecules, including serotonin. When the delta
granules are released by activated platelets, the serotonin works to amplify
the coagulation response.
Dr. Litinas and his team believe that in
depressed patients who have an associated risk of cardiovascular problems,
the blocking activity of SSRIs may have the side-effect of preventing the
serotonin uptake by platelets, making them less responsive to aggregation
and thereby improving the patients' cardiovascular health.
The researchers recruited 50 volunteers, 25
who were not taking antidepressant medications and 25 who were being treated
for depression with an SSRI. The team collected blood samples from each
volunteer at the beginning of the protocol and again at the study's fourth
week and eighth week.
When the platelets from healthy volunteers
were treated with platelet-activating substances at the 4-week time point,
95 percent of the cells aggregated. In contrast, the platelets of
participants taking an SSRI showed only 37 percent aggregation, indicating
that the SSRI had inhibited or changed the platelets' ability to clump
As the study progressed, the researchers
noticed that platelets taken from SSRI-treated patients at the 8-week mark
aggregated more than those drawn at the 4-week mark, suggesting that SSRIs
have the greatest impact on preventing platelet activation early in
"The reason we're doing this is to better the
lives of depressed patients," said Dr. Litinas. "There is clear evidence
that depressed patients have a higher risk of cardiovascular disease, and we
want to eliminate that. Since depression can be treated with an SSRI, maybe
the cardiovascular disease risk can also be decreased. We want our patients
to live longer and happier lives, without depression or the risk of heart
SOURCE: Presented at the American
Physiological Society's annual Experimental Biology conference, Anaheim, CA,
April 24-28, 2010.