LIPID-PEROXIDATION INDUCED IN-VIVO BY HYPERHOMOCYSTEINAEMIA IN PIGS

Much attention has been focused recently on the relationship between h omocysteinaemia and the development of premature atherosclerosis. Hype rhomocysteinaemia constitutes as strong a risk factor for the developm ent of the disease as either hypercholesterolaemia or smoking. Althoug h the mechanism involved is unclear homocysteine exhibits prooxidative activity in vitro. This finding suggests that it may be involved in t he oxidative modification of low density lipoprotein (LDL). In the cur rent study hyperhomocysteinaemia was induced in eight domestic pigs by intermittent exposure to nitrous oxide for 4 weeks. At necropsy, card iac tissue was removed and malondialdehyde (MDA) and the unsaturated f atty acid content were measured and compared with values obtained from air-breathing control animals. Nitrous oxide treated animals had sign ificantly higher tissue concentrations of MDA than the controls. There was also a reduction in the contribution of linoleic and linolenic ac ids to the total fatty acid content of heart. The hyperhomocysteinaemi c animals also had a significantly higher iron concentration in the he art than controls. Hyperhomocysteinaemia was associated with elevation s in tissue iron stores and increased in vivo lipid peroxidation. (C) 1997 Elsevier Science Ireland Ltd.