Emory
Scientist Awarded American Heart Association Grant To Study Depression/Heart
Disease Link
Viola Vaccarino,
M.D., Ph.D., of the Emory Department of Medicine's Division of Cardiology,
has received the American Heart Association's Established Investigator
Award. The $300,000 grant will support new Emory Heart Center research
into the mechanism by which depression may cause or contribute to the
development of cardiovascular disease (CVD).
Dr. Vaccarino points out
that researchers have long noted an apparent association between depression
and cardiovascular disease - but exactly what that link represents remains
a medical mystery. For example, depression may be an actual cause of
heart disease or people who have cardiovascular disease could simply
be more depressed than their healthier counterparts. Some scientists
have also argued that depression may be a marker of worse underlying
disease.
"In addition, depression
and cardiovascular disease may be linked, not because there's a direct
cause and effect, but because genetic or behavioral factors can influence
both conditions," says Dr. Vaccarino, who is an associate professor
of medicine at Emory's School of Medicine and an associate professor
of epidemiology at Emory's Rollins School of Public Health. "These factors
are difficult to account for in traditional study designs."
Dr. Vaccarino's research
team will be able to overcome many of the limitations of past studies
by using pairs of identical twins in which one sibling has major depression
and the other does not. " The advantage of our study is that, because
twins share their genetic makeup (which is identical if they are identical
twins) and rearing environment while growing up, they are matched on
numerous known and unknown factors," explains Dr. Vaccarino.
The Emory research will concentrate
on the role oxidation may play in the development of CVD. During normal
metabolism, cells produce small amounts of metabolites of oxygen, called
reactive oxygen species, which are potentially toxic and can induce
injury of body cells, including those in the artery walls. Oxidative
stress is a condition in which the production of these reactive oxygen
species exceeds the ability of cells to remove them, and is thought
to represent the earliest stage of CVD.
"Animal and human experimental
studies have found increases in a variety of oxidative markers due to
exposure to psychological stress and depression. Our study will be the
first to directly examine whether oxidative stress may represent a mechanism
through which depression leads to cardiovascular disease, " says Dr.
Vaccarino. " We will also examine genetic and environmental influences
on oxidative stress levels."
The Emory scientists will
examine markers of oxidative stress, inflammation, and subclinical CVD
in a sample of 320 twins drawn from a large national twin registry.
They will also use a variety of technologies, including Positron Emission
Tomography (PET) myocardial perfusion imaging, to look for subclinical
signs of CVD .
"I am honored to receive
the American Heart Association's Established Investigator Award and
very pleased it will enable us to investigate these important study
questions about oxidative stress, CVD risk and depression," says Dr.
Vaccarino. "Our study will be the first to examine the role of a novel
pathway, oxidative stress, as a potential explanation for the increased
cardiovascular risk in depression. The expertise of our multidisciplinary
team and the state-of-the-art core laboratories and diagnostic facilities
at Emory University offer a unique structural foundation and research
environment for achieving our objectives."
The study will begin July
1, 2002 and continue through June 30 of 2006.
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