Abstract
The significance of 5-lipoxygenase and myeloperoxidase activities has not been extensively studied among young male smokers. Leukotriene B4, 20-hydroxy-leukotriene B4, 20-carboxy-leukotriene B4 and 3-chlorotyrosine were measured in plasma and urinary samples of young male smokers at 8 hours following cigarette abstinence and an hour after cigarette smoking. Leukotriene B4 and 3-chlorotyrosine were determined in neutrophils isolated from these individuals. The levels of these markers were compared with those of age-matched controls. In vitro studies were performed to evaluate the production of leukotriene B4 and 3-chlorotyrosine from human neutrophils following exposure to nicotine and cotinine. Thirty male smokers (mean age, 27.4 years) and 28 male non-smokers (mean age, 28.7 years) were studied. Plasma levels of leukotriene B4, 20-carboxy-leukotriene B4 and 3-chlorotyrosine were higher in smokers than in non-smokers; leukotriene B4 and 20-carboxy-leukotriene B4 levels increased further an hour after cigarette smoking. Peripheral neutrophils isolated from smokers showed greater expressions of myeloperoxidase and 5-lipoxygenase activities compared with non-smokers, while plasma leukotriene B4 and 3-chlorotyrosine were correlated significantly with high-sensitivity C-reactive protein and plasma nicotine concentrations. Exposure of human neutrophils to nicotine and cotinine resulted in a higher production of leukotriene B4 and 3-chlorotyrosine. To conclude, leukotriene B4 and 3-chlorotyrosine levels are increased in young male cigarette smokers. These results suggest that cigarette smoking aggravates neutrophil-mediated inflammation by modulating the activities of myeloperoxidase and 5-lipoxygenase pathways.
Acknowledgements
We thank the study volunteers who participated in this study.
Declaration of interest
All authors do not have competing interests. This study is supported by the Singapore National Research Foundation and National Medical Research Council.
Notice of Correction
The version of this article published online ahead of print on 4 July 2012 contained an error. Figure 2A and 2B was by mistake omitted. The figures have been included correctly for this version.