Effects of Tobacco Smoke Exposure on Epigenetic Signatures and Immunotoxicological Reactions

Overview

Researchers have noted that active smoke exposure was possibly related to epigenetic mechanism,and may further influence reactive immunotoxicological reaction on human beings. Some studies have been reported that smoking reduction would decrease the prevalence of respiratory symptoms and urinary cotinine level, but the underlying epigenetic mechanism and the functional changes of immunotoxicological system were still unclear. We plan to examine the causal relationship between smoking reduction and alterations in epigenetic signatures/immunotoxicological reactions. Teenager Smoking Reduction Trial (TSRT) will be population-based trial among teenagers. Eligible teenagers will be recruited in Taipei City and urinary cotinine level will be used to monitor the exposure status of active smoking at baseline, 1-month and 3-month of the intervention process. We will assess the potential change in immunotoxicological markers, including Th1/Th2 cytokines and clinical immunological measurements, before and after the intervention program. Furthermore, whole-genome methylation and miRNA expression microarrays will be used to search candidate genes for teenager smoking exposure. We plan to develop a prediction model for immunotoxicological reaction by utilizing epigenetic signature data from microRNA expression and DNA methylation profiles based on machine learning methodologies. We will also establish a personalized epigenetic prediction model for allergy development and build the risk assessment platform for immunotoxicological reaction under tobacco smoke exposure. Finally, we will examine the causal relationship between epigenetic signatures and immunotoxicological reactions under an independent children's cohort.

Teenager Smoking Reduction Trial (TSRT) 1. Study subjects TSRT is a solution-oriented trial aiming to evaluate the effectiveness of tobacco smoke reduction among teenagers. Eligible teenagers will fit the following criteria: (a) age between 12 and 16 years old; (b) have active smoke habits in past 6 months; (c) amount of smoke exceed 10 cigarettes per week. The subjects will be recruited from our previous database for schoolchildren. Telephone interview will be used to screen the eligibility for the teenagers. Recruitment will occur over 3-month period from 2011 April to June. The procedure for TSRT is showed in figure 2. In this plan, we will recruit at least 31 asthmatic children and 31 non-asthmatic children who have active smoke habits. 2. Data collection A baseline data and at the 1-month and 2-month follow-up visits, the primary caregiver provided data by personal interview on parents reports. The demographic information in questionnaires included age, gender, level of education. Teenagers will report the frequency of cigarette smoking by using a structured questionnaire. The definition of tobacco smoke exposure including: (a) ''Do you currently smoke?''-yes/no; (b) ''When did you begin to smoke regularly?''; (c) Smokers were also asked for the number of cigarettes they smoked on an average day. Nicotine dependence will be examined by using structure questionnaires from Fagerstrom model. We will contact eligible teenagers individually to get informed consent before data collection. The effects of our teenager smoking reduction intervention program will be assessed by primary outcomes such as cotinine/creatinine ratio (CCR) and the status of tobacco smoke exposure from questionnaire. No matter which group the participant belongs to, intervention and usual control group, the secondary outcomes in all participants will be tested as follows: 1. Cytokines. We will test levels of interleukin 4, 5, 13 (IL-4, 5, 13), tumor necrosis factor-α (TNF-α), interferon-gamma (INF-γ) and toll-like receptors 2, 4, 9 (TLR-2, 4, 9). 2. Immunotoxicological reaction. We will determine levels of exhaled nitric oxide (eNO), serum eosinophil cationic protein (ECP) and absolute eosinophil count (AEC). 3. Oxidative stress markers. Levels of the markers 8-hydroxy-2-deoxyguanosine (8-OHdG), malondialdehyde (MDA) and F2-isoprostane (Iso-P) will be examined. After first session is applied, all participants will be tested for primary outcomes and secondary outcomes at baseline, month 1 and month 3 of the intervention process. We can then compare the biomarkers before and after the intervention program.