F2-isoprostanes from arachidonic acid -: Biomarkers of oxidative stress?

F-2-isoprostanes (F-2-IsoP) are prostaglandin isomers formed from arachidonic acid in a cyclooxigenase-independent free radical-catalyzed mechanism. Therefore they are potential indicators of oxidative stress. From the theoretically possible 64 isomers hitherto 15-F-2t- IsoP, 5-F-2t-IsoP, 5-F-2c-IsoP and 5-epi-5-F-2c-IsoP have been identified in humans. F-2-IsoP undergo beta-oxidation. 2,3-Diner-15 F-2t and 2,3-Diaor-5,6-dihydro-15-F-2t-IsoP are the identified metabolites. 15-F-2t IsoP is a potent smooth muscle cell constrictor modulating platelets as well as inducing proliferation of vascular smooth muscle cells. F-2t IsoP are measured after chromatographic purification by GC/MS, immune-enzyme or radioimmuno-assays. 15-F-2t-IsoP has been found in blood plasma, atherosclerotic lesions and urine of humans, 5-F-2t-IsoP in blood plasma and urine. 5-F-2c- and 5-epi-5-F-2c-IsoP were identified in urine. In the case ofnon-insuline dependent diabetes mellitus and smokers, the 15-F-2t-IsoP values are increased in blood plasma, atherosclerotic lesions and in that of hypercholesterolemia in LDL. in urine the amounts of 15-F-2t- and 5-F-2t-IsoP are increased in smokers and hypercholesterolemic persons. ol-Tocopherol supplementation decreases the urinary content of F-2-IsoP to normal levels. Supplementation of soy isoflavonoids does not influence urine level of F-2-IsoP in subjects with high-normal blood pressure. Urinary 15-F-2t-TsoP excretion is not dependent on the lipid content of the diet, but increased by a 24 h fasting period. A correlation between oxidative stress and risk factors for coronary heart disease is obvious.