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Benzene, toluene, ethylbenzene, and isomeric xylenes (BTEX) are by-products of tobacco smoke and traffic emissions. The aim of this study was to determine the contribution of cigarette smoking to urinary levels of BTEX present in humans. Nicotine and cotinine, biomarkers of exposure to tobacco smoke, as well as BTEX, were measured in urine of smokers (n = 70) and nonsmokers (n = 65) using headspace solid-phase microextraction (HS-SPME) followed by gas chromatography-mass spectrometry (GC-MS). In smokers, a significant correlation was found between urinary BTEX levels and nicotine and cotinine. In addition, significant regression models with nicotine and cotinine as predictors showed that BTEX in smokers' urine was predominantly derived from exposure to tobacco smoke. In nonsmokers a weak correlation between BTEX and nicotine and cotinine was found in urine. Further, there was a lack of significant contribution of BTEX to urinary nicotine and cotinine concentrations in nonsmokers. Thus, it was presumed that vehicle exhaust was the main source of exposure to BTEX in nonsmokers.

Changes in immune and inflammatory responses may play a crucial role in the development and progression of atherosclerosis, as an autoimmune, chronic and progressive inflammatory disease. Immunological activity and vascular inflammation during atherosclerosis can be modulated by autoimmune responses against self-antigens, according to changeable risk factors (cholesterol, oxidized low-density lipoprotein (ox-LDL) in the vascular wall, fatty acids, etc.), and accompanied by accumulation of leucocytes and proinflammatory cytokines, which stimulate the transcription of matrix metalloproteinases (MMPs), whose concentration are increased in foam cell-rich regions. Regulatory T cells (Tregs) represent a unique subpopulation of T cells specialized in the regulation of immune response and in the suppression of proatherogenic T cells. The aim of our study was to examine the interactions between the concentration of enzyme matrix metalloproteinases 2 and 9 (MMP-2 and 9) in urine and the percentage of Tregs in peripheral blood of two groups of patients: with carotid artery stenosis (CAS), undergoing surgery and with mild atherosclerosis (A) from general practice. The method of enzyme immunoassay (ELISA) was used to determine enzyme MMP expression, and Tregs was examined by flow cytometric analysis. Our data have showed a large increase in the enzyme MMP-2 and 9 in the urine of CAS and A patients in comparison with healthy controls and indicated this method as an easy marker for the monitoring of the development of atherosclerosis. Simultaneously, the diminished number of Tregs in the same patients pointed the importance of these regulatory mechanisms in the etiopathogenesis of atherosclerosis and possible Tregs-mediated therapy.

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