Identification of carcinogen DNA adducts in human saliva by linear quadrupole ion trap/multistage tandem mass spectrometry.

DNA adducts of carcinogens derived from tobacco smoke and cooked meat were identified by liquid chromatography-electrospray ionization/multistage tandem mass spectrometry (LC-ESI/MS/MS(n)) in saliva samples from 37 human volunteers on unrestricted diets. The N-(deoxyguanosin-8-yl) (dG-C8) adducts of the heterocyclic aromatic amines 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP), 2-amino-9H-pyrido[2,3-b]indole (AalphaC), 2-amino-3,8-dimethylmidazo[4,5-f]quinoxaline (MeIQx), and the aromatic amine, 4-aminobiphenyl (4-ABP), were characterized and quantified by LC-ESI/MS/MS(n), employing consecutive reaction monitoring at the MS(3) scan stage mode with a linear quadrupole ion trap (LIT) mass spectrometer (MS). DNA adducts of PhIP were found most frequently: dG-C8-PhIP was detected in saliva samples from 13 of 29 ever-smokers and in saliva samples from 2 of 8 never-smokers. dG-C8-AalphaC and dG-C8-MeIQx were identified solely in saliva samples of three current smokers, and dG-C8-4-ABP was detected in saliva from two current smokers. The levels of these different adducts ranged from 1 to 9 adducts per 10(8) DNA bases. These findings demonstrate that PhIP is a significant DNA-damaging agent in humans. Saliva appears to be a promising biological fluid in which to assay DNA adducts of tobacco and dietary carcinogens by selective LIT MS techniques.

Plasma cytokines, metabolic syndrome, and atherosclerosis in humans.

BACKGROUND: Interleukin-6 (IL-6) and tumor necrosis factor alpha (TNF-alpha) integrate inflammatory and adipose signaling but also have direct vascular effects. We hypothesized that plasma levels of IL-6 and soluble tumor necrosis factor alpha receptor 2 (sol-TNFR2) would be related to coronary atherosclerosis beyond established risk factors and the metabolic syndrome. METHODS: We examined the association of IL-6 and sol-TNFR2 with metabolic syndrome, C-reactive protein (CRP), and coronary artery calcification (CAC) in 875 asymptomatic participants in the Study of Inherited Risk of Coronary Atherosclerosis. RESULTS: IL-6 levels were 56% higher (p < .001) and sol-TNFR2 levels 16% higher (p < .001) in subjects with metabolic syndrome compared with those without. Both cytokines were associated with CAC beyond age, gender, Framingham risk scores, family history, metabolic syndrome, and CRP (odds ratio and 95% confidence interval of higher CAC for 1 SD increase in log-transformed cytokine levels: 1.23 [1.06-1.43], p = .006 for IL-6 and 1.15 [1.01-1.31], p = .04 for sol-TNFR2). In fact, cytokine levels were independently associated with CAC scores in the subgroup with metabolic syndrome and were additive to the homeostasis model assessment of insulin resistance in predicting CAC. CONCLUSIONS: Plasma IL-6 and sol-TNFR2 levels were independently associated with CAC, suggesting a role in integrating innate immune and adipose signaling in promoting atherosclerosis and cardiovascular risk. Measurement of their levels may facilitate cardiovascular risk prediction and targeting of therapeutic strategies.