Researchers Study Inflammation's Role in Atherosclerosis
Does a common
hormone known as angiotensin II play an important role in the development
of atherosclerosis, the build up of cholesterol and scar tissue inside
arteries? AIMS, the Atherosclerosis and Inflammatory Markers Study based
at Emory University, is designed to help answer that question.
Angiotensin II is not a "bad"
hormone, according to Emory Heart Center cardiologist W. Robert Taylor,
M.D., Ph.D. In fact, it is necessary for control of homeostasis -- it
helps regulate blood pressure control. However, as we age, the hormone
produces reactions in blood vessels that may contribute to heart disease.
"During our reproductive
years angiotensin II helps keep us alive if we are subjected to some
serious injury or extreme physical stress," explains Dr. Taylor, chief
investigator for AIMS. "But after middle age or so, it has some negative
effects on the vessel walls. It produces an inflammatory response which
is believed to be an important part of the development of atherosclerosis."
Angiotensin II already has
been linked to the development of atherosclerosis in several ways. "There
are data from our basic science lab that demonstrate that giving angiotensin
II to animals accelerates the development of atherosclerosis. Importantly,
the converse is also true in that blocking endogenous angiotensin II
prevents the development of atherosclerosis," says Dr. Taylor. "In addition,
there are some human data that suggest that this is true in people,
too. For example, when we look at outcomes in patients treated with
ACE (angiotensin converting enzyme) inhibitors which block angiotensin
II formation, cardiovascular mortality is lower."
Emory researchers will look
at the effect of an angiotensin II receptor blocker on serum markers
of atherosclerosis such as growth factors, cytokines and other signs
of vascular inflammation and oxidative stress, according to Dr. Taylor.
AIMS, which is sponsored by Sankyo Pharma Inc.'s Development Division,
hopes to enroll approximately 220 patients with peripheral vascular
disease (PVD) involving the lower extremities. In PVD, a disease that
affects approximately eight million people in the U.S., arteries that
carry blood to the legs (or, less often, the arms) become narrowed or
clogged by atherosclerosis, slowing or stopping the flow of blood.
Half of the study participants
will receive a placebo and half will receive a new angiotensin II blocker
known as CS866 (also called olmesartan) .Blood tests for atherosclerosis
markers as well as ultrasound studies documenting vascular reactivity
and the health of blood vessels will be performed over a period of 12
Most patients with PVD who
are in stable condition and are not currently taking an ACE inhibitor
or angiotensin receptor blocker are eligible to participate in the study.
For information on referring a patient to participate in AIMS, call
Jane Guidot at 404-321-6111, ext. 4183.