Iron-catalyzed lipid peroxidation in aortic cells in vitro: protective effect of extracellular magnesium

• Published in: Atherosclerosis Vol. 175; no. 1; pp. 15 - 22
• Main Authors: Kostellow, Adele B., Morrill, Gene A.
• Format: Journal Article
• Language: English
• Published: Amsterdam Elsevier Ireland Ltd 01.07.2004; Elsevier
• Subjects: Aldehydes - metabolism; Animals; Aorta - metabolism; Aortic cells; Atherosclerosis (general aspects, experimental research); Biological and medical sciences; Blood and lymphatic vessels; Blood vessels and receptors; Cardiology. Vascular system; Cells, Cultured; Diseases of the aorta; Dose-Response Relationship, Drug; Ferric Compounds - pharmacology; Ferrous Compounds - pharmacology; Fundamental and applied biological sciences. Psychology; Glutathione; Glutathione - metabolism; Humans; Ionophores - pharmacology; Iron; Iron - pharmacology; Lipid peroxidation; Lipid Peroxidation - drug effects; Magnesium; Magnesium - pharmacology; Magnetic Resonance Spectroscopy; Male; Malondialdehyde - metabolism; Medical sciences; Membrane lipids; Muscle, Smooth, Vascular - metabolism; Oxyquinoline - pharmacology; Rats; Rats, Sprague-Dawley; Vertebrates: cardiovascular system; Lipid peroxidation; Membrane lipids; Iron; Magnesium; Aortic cells; Glutathione; Cardiovascular disease; Inorganic element; Artery; Vascular disease; Prevention; Blood vessel; Atherosclerosis; Aorta; Circulatory system; Peroxidation
• ISSN: 0021-9150; 1879-1484
• DOI: 10.1016/j.atherosclerosis.2004.01.040

Low serum Mg 2+ has been associated with an increased incidence of cardiovascular pathology in human populations. We investigated the effect of extracellular Mg 2+ on Fe-catalyzed lipid peroxidation in rat aortic segments and in human aortic smooth muscle cells. Products of phospholipid oxidation [malonaldehyde (MDA) and 4-hydroxyalkenals (4-HA)], loss of fatty acyl double bonds (by proton-NMR) and glutathione levels indicated that exogenous ferric ions were several-fold more effective than ferrous ions in causing lipid peroxidation. Increased peroxidation was detectable at <1.0 μM Fe 3+. Exogenous ferric iron-ionophore, 8-hydroxyquinoline, did not increase peroxidation by ferric ion, suggesting that Fe-catalyzed lipid peroxidation occurred at the cell surface. As ionized serum [Mg 2+] o was lowered from the physiological (0.7–0.96 mM) into the pathophysiological range (0.3–0.5 mM) in Fe 3+-containing medium, MDA/4-HA levels increased two to three-fold, with a concomitant loss of fatty acyl double bonds and decreased extracellular glutathione. Conversely, MDA/4-HA decreased as ionized Mg 2+ was increased, accompanied by a rise in extracellular glutathione. The results indicate that Mg 2+ protects aortic cell plasma membranes from ferric iron-catalyzed lipid peroxidation and that this is a contributing factor in the protective action of ionized Mg 2+ on the cardiovascular system.