Determination of 4-(Methylnitrosamino)-1-(3-Pyridyl)-1-Butanone (NNK) arising from tobacco smoke in airborne particulate matter

The most important tobacco-specific nitrosamine found in cigarette smoke and formed in ageing smoke after cigarettes are extinguished is 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone (NNK). It is formed from nitrosation of nicotine, under particular conditions both in indoor and outdoor environments. NNK has been classified as a potent lung carcinogen which is expected to be found primarily in the particle-phase and to be stable in particulate matter. In this study tests have been carried out to show that a bisulfate-treated filter is more efficient than an untreated filter to collect both nicotine and NNK, and that the latter is stable in outdoor particulate matter. To characterize NNK in the outdoor environment, airborne samples were collected from 11 cities in USA, UK, Hong Kong and Malta with characteristics varying from low to high population densities and from urban to suburban to rural, and with desert characteristics and distinct climates. It has been shown that airborne particle + gas phase nicotine and particle-phase NNK behave in a linearly correlated manner. A seasonal analysis was carried out on a subset of data available from five sites in California, where the load of NNK in PM10 is driven by long range transport of the air masses passing over densely populated cities. In the winter season, the load of NNK in PM is higher than in summer in a statistically significant manner. The contamination of PM with NNK shows variability, but is observed at all sites. This paper highlights the potential risk of chronic exposure to NNK in particulate matter by the inhalation pathway.

Current-Smoking alters Gene Expression and DNA Methylation in the Nasal Epithelium of Asthmatics

Current-smoking contributes to worsened asthma prognosis, more severe symptoms and limits the beneficial effects of corticosteroids. As the nasal epithelium can reflect smoking-induced changes in the lower airways, it is a relevant source to investigate changes in gene expression and DNA methylation. This study explores gene expression and DNA methylation changes in current and ex-smokers with asthma. Matched gene expression and epigenome-wide DNA methylation samples collected from nasal brushings of 55 patients enrolled in a clinical trial investigation of current and ex-smoker asthma patients were analysed. Differential gene expression and DNA methylation analyses were conducted comparing current- vs ex-smokers. Expression quantitative trait methylation (eQTM) analysis was completed to explore smoking relevant genes by CpG sites that differ between current and ex-smokers. To investigate the relevance of the smoking-associated DNA methylation changes for the lower airways, significant CpG sites were explored in bronchial biopsies from patients who had stopped smoking. 809 genes and 18,814 CpG sites were differentially associated with current-smoking in the nose. The cis-eQTM analysis uncovered 171 CpG sites whose methylation status associated with smoking-related gene expression, including AHRR, ALDH3A1, CYP1A1 and CYP1B1. Methylation status of CpG sites altered by current-smoking reversed with one-year smoking cessation. We confirm current-smoking alters epigenetic patterns and affects gene expression in the nasal epithelium of asthma patients, which is partially reversible in bronhcial biopsies after smoking cessation. We demonstrate the ability to discern molecular changes in the nasal epithelium, presenting this as a tool in future investigations into disease-relevant effects of tobacco smoke.

Impact of environmental tobacco smoke exposure on anaesthetic and surgical outcomes in children: a systematic review and meta-analysis

BACKGROUND

Tobacco smoke exposure in adults is linked to adverse anaesthetic and surgical outcomes. Environmental tobacco smoke (ETS) exposure, including passive smoking, causes a number of known harms in children, but there is no established evidence review on its impact on intraoperative and postoperative outcomes.

OBJECTIVES

To undertake a systematic review of the impact of ETS on the paediatric surgical pathway and to establish if there is evidence of anaesthetic, intraoperative and postoperative harm.

ELIGIBILITY CRITERIA PARTICIPANTS

Children aged 0-18 years undergoing anaesthetic or surgical procedures, any country, English language papers.

EXPOSURE

ETS exposure assessed via questioning, observation or biological marker.

OUTCOME MEASURES

Frequency of respiratory and other adverse events during anaesthesia, surgery and recovery, and longer term surgical outcomes.

RESULTS

28 relevant studies were identified; 15 considered anaesthetic outcomes, 12 surgical outcomes, and 1 a secondary outcome. There was sufficient evidence to demonstrate that environmental smoke exposure significantly increased risk of perianaesthetic respiratory adverse events (Pooled risk ratio 2.52 CI 95% 1.68 to 3.77), and some evidence that ear and sinus surgery outcomes were poorer for children exposed to ETS.

CONCLUSIONS

ETS exposure increases the risk of anaesthetic complications and some negative surgical outcomes in children, and this should be considered when planning surgery. Research is required to demonstrate whether changes in household smoking behaviour prior to surgery reduces risk of adverse outcomes, and to close the evidence gap around other outcomes such as wound healing and respiratory infections.

TRIAL REGISTRATION NUMBER

Review registration number 42014014557.