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(Arteriosclerosis, Thrombosis, and Vascular Biology. 2008;28:1024.)
© 2008 American Heart Association, Inc.

Clinical and Population Studies

Accumulation of Zinc in Human Atherosclerotic Lesions Correlates With Calcium Levels But Does Not Protect Against Protein Oxidation

Nadina Stadler; Naomi Stanley; Sylvia Heeneman; Vladimir Vacata; Mat J.A.P. Daemen; Paul G. Bannon; Johannes Waltenberger; Michael J. Davies

From the Heart Research Institute (N. Stadler, N. Stanley, M.J.D.), Sydney, Australia; the Cardiovascular Research Institute Maastricht (CARIM) (N. Stadler, S.H., M.J.A.P.D., J.W.), Maastricht, The Netherlands; Gemeinschaftspraxis für Laboratoriumsmedizin (V.V.), Leverkusen, Germany; and the Baird Institute for Heart and Lung Surgical Research (P.G.B.), Sydney, Australia.

Correspondence to Prof Michael J. Davies, The Heart Research Institute, 114 Pyrmont Bridge Road, Camperdown, Sydney, NSW 2050, Australia. E-mail daviesm{at}hri.org.au

Abstract

Objective— Oxidized lipids and proteins, as well as decreased antioxidant levels, have been detected in human atherosclerotic lesions, with oxidation catalyzed by iron and copper postulated to contribute to lesion development. Zinc has been postulated to displace iron from critical sites and thereby protect against damage. In this study, metal ion and protein oxidation levels were quantified in human carotid and abdominal artery specimens containing early-to-advanced lesions, to determine whether zinc concentrations correlate inversely with iron levels and protein oxidation.

Methods and Results— Metal ions were quantified by EPR and inductively coupled plasma mass spectroscopy. Native and oxidized protein side-chains were quantified by high-performance liquid chromatography. Elevated levels of zinc (6-fold) were detected in advanced lesions compared to healthy tissue or early lesions. Zinc did not correlate negatively with iron or copper levels suggesting that zinc does not displace these metal ions. Highly significant positive correlations (P<0.005) were detected between zinc and calcium levels.

Conclusions— Zinc did not correlate with low iron levels and reduced protein oxidation. These data indicate that zinc does not prevent protein oxidation in advanced lesions. The reported protective effect of zinc accumulation is proposed to be associated with lesion calcification.

Oxidation of lipids and proteins has been linked to the development of atherosclerosis; zinc has been proposed as a protective agent. Zinc levels are elevated in advanced lesions but correlate positively with iron concentrations and do not correlate with protein oxidation markers, indicating that zinc does not prevent protein oxidation.

Key Words: atherosclerosis • iron • zinc • protein oxidation • calcium