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Iron and Heart Disease |
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Iron and Heart Disease |
Why are we studying iron?
Several large studies suggest that high levels of iron may increase
the risk of heart attack and other blood vessel diseases. Experiments
in animals suggest that high levels of iron may be harmful to
blood vessels, particularly to the inner-linning of these vessels
which is called the endothelium.
What is the endothelium?
The endothelium is the inner lining of
cells in blood vessels. It performs functions essential to these
vessels including the regulation of blood clotting by releasing
a number of factors including nitric oxide. We are able to measure
how well the endothelium works by using ultrasound and other techniques
to assess blood vessel dilation.
What happens to the endothelium in atherosclerosis?
In atherosclerosis, release of nitric oxide from endothelial cells
is impaired. Since nitric oxide produces vasodilation and prevents
platelet clumping, this abnormality may increase the risk for
blood clot formation and vasospasm in the heart and brain. These
abnormalities may lead to heart attack, stroke, and/or sudden
death.
We believe that reducing body iron may improve the release of
nitric oxide from the endothelium and thereby reduce the risk
of cardiovascular disease.
What does the study involve?
The study involves one 4-hour visit to the Coronary Health Unit.
A small plastic tube will be inserted in the artery in your arm
(brachial artery) using a local anesthetic. You will be asked
to lie quietly in bed for 4 hours while measurements of blood
vessel function are made before and after deferoxamine treatment.
Two inflatable cuffs will be put on your arm, and will squeeze
your arm very slightly on and off throughout the study. Upon completion
of the study, you will be paid a stipend of $100. We will also
compensate you for parking in the Doctor's Office Building garage
at Boston Medical Center.
Are there risks involved?
Deferoxamine is approved by the Food and Drug Administration for
the treatment of iron overload and has been given safely to thousands
of patients. During our studies, a few patients have developed
local redness in the arm which ceases after stopping the medication.
The total amount of iron removed during the study is very small
and will not adversely affect your health.
Who is eligible for the study?
To be eligible for the study, you must have proven coronary artery
disease (by angiogram, history of a heart attack, or a positive
stress test). You cannot be taking regular antioxidant supplements
including vitamin E and vitamin C. We also are excluding people
who have smoked within one month and patients with diabetes mellitus
requiring insulin.
