title: [Homocysteine--a risk factor for atherosclerosis].
abstract: Elevated plasma homocysteine is a new risk factor for atherosclerotic vascular disease resulting in progressive atherogenesis in the arteries of the limbs, the coronary arteries and the cerebrovascular system. Hyperhomocysteinemia may be induced by failure or decreased enzyme activity of the cystathionine-beta-synthase and methylenetetrahydrofolate reductase due to genetic mutation or deficiency of folic acid, vitamin B12 and vitamin B6. Oxidation of homocysteine to homocystine is accompanied with production of hydrogen peroxide inducing damage of endothelium through oxidative stress. The injury of the endothelium by homocysteine can be shown by measuring flow-induced vasodilation in men. The abnormalities of coagulation found in hyperhomocysteinemia is related to the impairment of the function of endothelial cells and inhibition of the thrombomodulin-protein C and glycosaminoglycan-antithrombin-III anticoagulant system. Homocysteine decreases the level of glutathione peroxidase in the endothelial cells, and inhibits its activation leading to the impairment of oxidative defensive mechanism, and to the free radical-induced NO-inactivation. In decreasing of plasma homocysteine level and preventing its influence on endothelium, moreover in improving of endothelial function the folic acid has cardinal importance, however the vitamin B12 and vitamin B6 also play role in the maintenance of normal homocysteine level of blood.
authors.affiliation: Siklósi Kórház Kht., Belgyógyászati Osztály.
authors.forename: L
authors.initials: L
authors.lastname: Debreceni
mesh_terms: D000975:Antioxidants / Q000627:therapeutic use; D001161:Arteriosclerosis / Q000097:blood / Q000209:etiology* / Q000378:metabolism* / Q000517:prevention & control; D018450:Disease Progression; D004730:Endothelium, Vascular / Q000187:drug effects / Q000378:metabolism*; D005492:Folic Acid / Q000627:therapeutic use; D006710:Homocysteine / Q000097:blood*; D006801:Humans; D020138:Hyperhomocysteinemia / Q000097:blood / Q000150:complications* / Q000188:drug therapy / Q000378:metabolism*; D018384:Oxidative Stress / Q000187:drug effects; D012307:Risk Factors; D013927:Thrombosis / Q000209:etiology / Q000378:metabolism; D016896:Treatment Outcome; D014805:Vitamin B 12 / Q000627:therapeutic use; D025101:Vitamin B 6 / Q000627:therapeutic use
chemical_list: D000975:Antioxidants; D006710:Homocysteine; D025101:Vitamin B 6; D005492:Folic Acid; D014805:Vitamin B 12