Plasma 3-Nitrotyrosine in Cigarette Smokers

Peroxynitrite has been associated with increased oxidative reactions and DNA damage in inflamed tissues as it may cause a reduction of plasma antioxidants as well. Nitration of tyrosine residues of proteins leads to the production of 3-nitrotyrosine (NTYR), which may be considered as a marker of NO · -dependent oxidative damage. We developed a highly sensitive method to detect NTYR in human plasma and tested it in cigarette smokers and in healthy control subjects. Peripheral venous blood (10 ml) was obtained in 20 healthy, asymptomatic cigarette smokers (13 males, 7 females; age: 49 ± 11 yr) and in 18 healthy nonsmokers (10 males and 8 females; age: 36 ± 6 yr). In smokers, plasma nicotine, cotinine, and expired CO levels were measured. NTYR was determined with a sequential HPLC/gas chromatography–thermal energy analysis (GC-TEA) technique. The total plasma Trolox®-equivalent antioxidant capacity (TEAC) was also measured using metmyoglobin as peroxidase and a phenothiazine as a radical donor. NTYR was dete...