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Excess Iron Damages Blood Vessels

Although iron is an essential and important nutrient, excessive levels
can cause significant harm. A new study has shown that excess iron can
cause damage to the endothelium, the inner lining of blood vessels,
boosting a person's chances of developing hardening of the arteries
(atherosclerosis) and heart attack.

The mechanism of action of this effect seems to be that the high iron
levels impede the action of nitric oxide, a chemical released by the
endothelium, which aids in keeping blood vessels relaxed.

According to study lead investigator Dr. Hidehiro Matsuoka of Kurume
Medical School, consuming high amounts of iron over the long term may
increase iron levels in the body. He also said that people should get
regularly tested for high iron levels if they are over 40 and have other
risk factors for heart disease, such as high blood pressure or diabetes.

 * 

    Researchers injected 10 healthy volunteers with high doses of iron
    (0.7 milligrams per kilogram body weight) and used ultrasound imaging
    to observe arterial wall functioning.

 * 

    The excess iron raised levels of malondialdehyde, a chemical marker
    for oxidation, and inhibited normal endothelial function.

 *  As a separate part of the study, researchers also monitored the
    effects of lowering iron blood levels in 10 cigarette smokers and
    found that this caused endothelial function to return to normal.

The study also could help to explain why premenopausal women have less
heart disease, since iron is removed from the body each month during
menstruation.

Meeting of the American Heart Association's Council for High Blood
Pressure Research October 2000

 (HOME) ________________________________________________________________________________ Article: iron and  atherosclerosis.



Proc Natl Sci Counc Repub China B 2000 Oct;24(4):151-5

Iron and atherosclerosis.

Chau LY

Division of Cardiovascular Research, Institute of Biomedical Sciences, Academia
Sinica, Taipei, Taiwan, ROC.

Iron is a vital element in life. However, it may participate in diverse
pathological processes by catalyzing the formation of reactive oxygen free
radicals. During the past decade, considerable evidence has supported the role
of oxidative stress in the development of atherosclerosis and related
cardiovascular diseases. The oxidation of low-density lipoprotein (LDL) and
lipid is believed to be one of the crucial events leading to plaque formation in
vasculature. It has been hypothesized that iron-mediated oxidation is involved
in this process. In favor of this idea, several epidemiological studies have
shown that the level of body iron stores is positively correlated with the
incidence of coronary heart disease in human populations. However, some studies
have yielded conflicting results. Recently, studies conducted in our laboratory
and others have demonstrated that iron deposition is prominent in human
atherosclerotic lesions. The iron deposits appear to colocalize with ceroid,
which is an end product of extensively oxidized lipid and protein complex, in
lesions, providing histological evidence to support the iron hypothesis.
Additional experiments in animals have further revealed that the severity of
atherosclerosis can be markedly influenced by iron overload or deficiency.
Collectively, these data provide a strong pathological basis to support the
detrimental role of iron in vascular damage and progression of the disease.

PMID: 11087066, UI: 20537901

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