Developmental Pathways from Genetic, Prenatal, Parenting and Emotional/Behavioral Risk to Cortisol Reactivity and Adolescent Substance Use: A TRAILS Study

Cortisol reactivity is a frequently studied biomarker of substance use, though infrequently examined in adolescence. However, past research provides evidence that multiple developmental influences, including genetics and both prenatal and postnatal environmental influences, contribute both to cortisol reactivity and adolescent substance use. The aim of this study was to assess the impact of these earlier developmental influences on cortisol reactivity to a social stress challenge and adolescent substance use (smoking, alcohol, and marijuana use frequency assessed at age 16 years), using data from the TRacking Adolescents' Individual Lives Survey (TRAILS; N= 2230 adolescents, 51% female). Developmental pathways included polygenic risk, prenatal stress, warm parenting (age 11), and internalizing and externalizing problems (intercepts and change from 11-16 years). Cortisol reactivity was associated with smoking but not alcohol or marijuana use. Externalizing problems were the stronger predictor of adolescent substance use, but internalizing problems also had an important role. Prenatal stress and middle childhood parenting operated via middle childhood externalizing problems, and parenting also operated via trajectories of growth of externalizing problems in predicting adolescent substance use outcomes. Further, there were protective effects of internalizing problems for alcohol and marijuana use in the context of a more comprehensive model. These developmental influences did not attenuate the association of cortisol reactivity and smoking. These findings suggest a need to understand the broader developmental context regarding the impact of internalizing pathways to substance use, and that it is unlikely that cortisol reactivity and smoking are associated solely because of common developmental influences.

Nicotine Absorption Profile Among Regular Users of a Pod-Based Electronic Nicotine Delivery System

This case series characterizes nicotine absorption among adults who regularly use a pod-based electronic nicotine delivery system.

Mediation by Placental DNA Methylation of the Association of Prenatal Maternal Smoking and Birth Weight

Prenatal maternal smoking is a risk factor for lower birth weight. We performed epigenome-wide association analyses of placental DNA methylation (DNAm) at 720,077 cytosine-phosphate-guanine (CpG) sites and prenatal maternal smoking among 441 mother-infant pairs (2010-2014) and evaluated whether DNAm mediates the association between smoking and birth weight using mediation analysis. Mean birth weight was 3,443 (standard deviation, 423) g, and 38 mothers (8.6%) reported smoking at a mean of 9.4 weeks of gestation. Prenatal maternal smoking was associated with a 175-g lower birth weight (95% confidence interval (CI): -305.5, -44.8) and with differential DNAm of 71 CpGs in placenta, robust to latent-factor adjustment reflecting cell types (Bonferroni-adjusted P < 6.94 × 10-8). Of the 71 CpG sites, 7 mediated the association between prenatal smoking and birth weight (on MDS2, PBX1, CYP1A2, VPRBP, WBP1L, CD28, and CDK6 genes), and prenatal smoking × DNAm interactions on birth weight were observed for 5 CpG sites. The strongest mediator, cg22638236, was annotated to the PBX1 gene body involved in skeletal patterning and programming, with a mediated effect of 301-g lower birth weight (95% CI: -543, -86) among smokers but no mediated effect for nonsmokers (β = -38 g; 95% CI: -88, 9). Prenatal maternal smoking might interact with placental DNAm at specific loci, mediating the association with lower infant birth weight.

Identification of gene and microRNA changes in response to smoking in human airway epithelium by bioinformatics analyses

Smoking is a substantial risk factor for many respiratory diseases. This study aimed to identify the gene and microRNA changes related to smoking in human airway epithelium by bioinformatics analysis.From the Gene Expression Omnibus (GEO) database, the mRNA datasets GSE11906, GSE22047, GSE63127, and microRNA dataset GSE14634 were downloaded, and were analyzed using GEO2R. Functional enrichment analysis of the differentially expressed genes (DEGs) was enforced using DAVID. The protein-protein interaction (PPI) network and differentially expressed miRNAs (DEMs)- DEGs network were executed by Cytoscape.In total, 107 DEGs and 10 DEMs were determined. Gene Ontology (GO) analysis revealed that DEGs principally enriched in oxidation-reduction process, extracellular space and oxidoreductase activity. Kyoto Encyclopedia of Genes and Genomes (KEGG) pathway demonstrated that DEGs were principally enriched in metabolism of xenobiotics by cytochrome P450 and chemical carcinogenesis. The PPI network revealed 15 hub genes, including NQO1, CYP1B1, AKR1C1, CYP1A1, AKR1C3, CEACAM5, MUCL1, B3GNT6, MUC5AC, MUC12, PTGER4, CALCA, CBR1, TXNRD1, and CBR3. Cluster analysis showed that these hub genes were associated with adenocarcinoma in situ, squamous cell carcinoma, cell differentiation, inflammatory response, oxidative DNA damage, oxidative stress response and tumor necrosis factor. Hsa-miR-627-5p might have the most target genes, including ITLN1, TIMP3, PPP4R4, SLC1A2, NOVA1, RNFT2, CLDN10, TMCC3, EPHA7, SRPX2, PPP1R16B, GRM1, HS3ST3A1, SFRP2, SLC7A11, and KLHDC8A.We identified several molecular changes induced by smoking in human airway epithelium. This study may provide some candidate genes and microRNAs for assessing the risk of lung diseases caused by smoking.

Development of a UPLC-ESI-MS/MS method to measure urinary metabolites of selected VOCs: Benzene, cyanide, furfural, furfuryl alcohol, 5-hydroxymethylfurfural, and N-methyl-2-pyrrolidone

We report on the development of an ultra-performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for simultaneously measuring eight biomarkers of volatile organic compound (VOC) exposure, with potential application to e-cigarette aerosol biomonitoring. Phenylmercapturic acid (PMA) and trans, trans-muconic acid (tt-MA) are metabolites of benzene; 2-aminothiazoline-4-carboxylic acid (ATCA) is a metabolite of cyanide; N-2-furoylglycine (N2FG) is a metabolite of furfural and furfuryl alcohol; 5-hydroxymethylfuroic acid (HMFA), 5-hydroxymethyl-2-furoylglycine (HMFG), and 2,5-furandicarboxylic acid (FDCA) are metabolites of 5-hydroxymethylfurfural; and 5-hydroxy-N-methylpyrrolidone (5HMP) is a metabolite of N-methyl-2-pyrrolidone. A pentafluorophenyl-modified silica column was used for chromatographic separation. The overall run time for the method is about 6 min per sample injection. The method has low to sub-nanograms per milliliter sensitivity, linearity over 3 orders of magnitude, and precision and accuracy within 15%. The method was used to measure human urine samples. Results showed that people with known benzene exposure (daily cigarette smokers) had higher levels of tt-MA and PMA compared with non-smokers. The method is advantageous for high-throughput analysis of selected VOC metabolites in large-scale, population-based studies such as the National Health and Nutrition Examination Survey (NHANES). Quantifying these urinary biomarkers is important to public health efforts to understand human exposure to VOCs from various sources, including tobacco products and electronic nicotine delivery systems.

Saliva DNA Methylation Detects Nascent Smoking in Adolescents

Objectives: Early identification of smoking, essential for the successful implementation of interventions, arrests the escalation of smoking and smoking-associated risk behaviors in adolescents. However, because nascent smoking is typically episodic and infrequent, enzyme-linked immunoassay reagent-based approaches that detect cotinine, a key nicotine metabolite, are not effective in identifying adolescents in the earliest stages of smoking. Epigenetic methods may offer an alternative approach for detecting early-stage smokers. In prior work, we and others have shown that the methylation status of cg05575921 of whole-blood DNA accurately predicts smoking status in regularly smoking adults and is sensitive to nascent smoking. Yet, the blood draws necessary to obtain DNA for this method may be poorly accepted by adolescents. Saliva could be an alternative source of DNA. However, the ability of saliva DNA methylation status to predict smoking status among adolescents is unknown. Methods: To explore the possibility of using salivary DNA for screening purposes, we examined the DNA methylation status at cg05575921 in saliva DNA samples from 162 high school aged subjects for whom we also had paired serum cotinine values. Results: Overall, the reliability of self-report of nicotine/tobacco use in these adolescents was poor with 67% of all subjects whose serum levels of cotinine was ≥2 ng/mL (n = 75) denying any use of nicotine-containing products in the past 6 months. However, the correspondence of the two biological measures of smoking was high, with serum cotinine positivity being strongly correlated with cg05575921 methylation (p < 0.0001). Receiver operating characteristic (ROC) analyses showed that cg05575921 methylation status could be used to classify those with positive serum cotinine values (≥2 ng/mL) from those denying smoking and have undetectable levels of cotinine. Conclusions: We conclude that saliva DNA methylation assessments hold promise as a means of detecting nascent smoking.

Nicotine absorption during electronic cigarette use among regular users

BACKGROUND

The capability of electronic cigarette devices (e-cigs) to deliver nicotine is key to their potential to replace combustible cigarettes. We compared nicotine delivery and subjective effects associated with the use of two classes of e-cigarettes and cigarettes.

METHODS

14 e-cigarette users were instructed to vape their own e-cigarette device every 20 seconds for 10 minutes while blood was drawn at 1, 2, 4, 6, 8, 10,12, and 15 minutes after initiating vaping. Users rated withdrawal symptoms and side effects before and after vaping. E-cigarette devices were classified as first-generation (same size as cigarette, no activation button) or advanced (larger than cigarette with an activation button). Separately, 10 cigarette smokers completed a similar protocol. Fisher's Exact Test and two-sided t-tests were used as appropriate to determine differences in outcomes between first-generation e-cigarette users, advanced e-cigarette users, and smokers.

RESULTS

Compared to first-generation devices, advanced devices were associated with greater serum nicotine Cmax (ng/ml) (11.5 v. 2.8, p = 0.0231) and greater nicotine boost (ng/ml) (10.8 v. 1.8, p = 0.0177). Overall, e-cigarettes users experienced a significant reduction in withdrawal and craving, although there were no significant differences between users of first-generation and advanced devices. Comparing e-cigarettes overall to cigarettes, cigarettes were associated with greater Cmax (25.9 v. 9.0, p = 0.0043) and greater nicotine boost (21.0 v. 8.2, p = 0.0128).

CONCLUSIONS

Advanced e-cigarettes delivered significantly more nicotine than first-generation devices but less than combustible cigarettes. Overall, e-cigarette use was associated with a reduction in withdrawal and craving with no reported side effects. The wide variation in nicotine absorption from different e-cigarette devices should be considered in studies of e-cigarettes for smoking cessation.

Overexpression of chitotriosidase and YKL-40 in peripheral blood and sputum of healthy smokers and patients with chronic obstructive pulmonary disease

Background

Despite the absence of endogenous chitin in humans, chitinases are present in the serum of healthy subjects and their levels are increased in a variety of chronic inflammatory conditions. It has been shown that chitotriosidase and structurally related chitinase-like protein-YKL-40 contribute to the pathogenesis of COPD. However, details regarding the relation of their systemic and local airways levels remain unknown.

Objectives

To examine peripheral blood and sputum chitotriosidase and YKL-40 expression in smokers and patients with COPD.

Methods

Forty patients with COPD, 20 healthy smokers and 10 healthy never-smokers were studied. Serum and induced sputum chitotriosidase protein and activity levels, YKL-40 concentrations, and their gene expression in sputum cells and peripheral blood mononuclear cells (PBMC) were evaluated.

Results

Both chitotriosidase protein levels and activity were higher in sputum obtained from COPD subjects compared to healthy never-smokers (P<0.05 and P<0.01, respectively). A similar pattern was observed for PBMC chitotriosidase mRNA expression (P<0.001). YKL-40 serum concentrations were elevated in healthy smokers and COPD subjects compared to healthy never-smokers (P<0.001 and P<0.01, respectively). In sputum, YKL-40 levels were increased in COPD compared to healthy never-smokers (P<0.01). PBMC YKL-40 mRNA expression was increased in COPD and healthy smokers compared to healthy never-smokers (P<0.0001). No associations were found between chitotriosidase or YKL-40 peripheral blood levels and sputum levels.

Conclusions

Our results demonstrate that chitotriosidase and YKL-40 are overexpressed in peripheral blood and airways in both healthy smokers and COPD subjects which may indicate smoking-related activation of macrophages, neutrophils, and epithelial cells.

Tissue P16 is Associated with Smoking Status among Indonesian Nasopharyngeal Carcinoma Subjects

Background: Nasopharyngeal carcinoma (NPC) is a malignancy with high incidence in Southern China and South-East Asia. NPC incidence among males in Indonesia is estimated around 8.3/100,000 populations. Tobacco smoking is a common risk factor for cancer, including NPC. P16 is one of the key proteins related to the activation of apoptotic pathways, that commonly change during carcinogenesis. Carcinogenesis is often related to environmental exposure, including tobacco smoke. Objective: To analyze the association between P16 protein and smoking status among NPC subjects in Indonesia. Methods: Forty formalin fixed-paraffin embedded NPC tissue samples of known smoking status (20 smokers, 20 non-smokers) were collected from the Department of Anatomical Pathology, Dr. Sardjito Hospital, Yogyakarta. P16 was detected by immunohistochemistry staining. German semi-quantitative scoring system was applied to the P16 staining. Expression index with the score of 0 to 3 was classified as negative staining, meanwhile 4 to 12 was classified as positive staining. The association between P16 (score) and smoking status among NPC patients was analyzed using Fischer exact test. One-sided p ≤ 0.05 was considered as statistically significant. Results: All samples were Javanese males, with age range 25-76 years old. P16 positive staining among smokers was 5% (1/20), while among non-smokers was 40% (8/20). P16 among smokers was significantly lower than non-smokers patients (p=0.010). No difference was found between quantity of smoke and P16 score. Conclusion : A significant association between P16 and smoking status in Indonesian NPC patients has been revealed. The result of this study may be used to improve prevention and management of NPC cases related to smoking habit in Indonesia.

Effects of extracellular Hsp70 and cigarette smoke on differentiated THP-1 cells and human monocyte-derived macrophages

Extracellular Hsp70 (eHsp70) can act as pro-inflammatory mediator and is elevated in blood of chronic obstructive pulmonary disease (COPD) patients. Most of those patients are smokers, and it was suggested previously that cigarette smoke might induce Hsp70 secretion from the circulating cells. Therefore, we aimed to explore inflammation-associated effects of cigarette smoke extract (CSE) and its combinations with eHsp70 in monocyte-derived macrophages (MDMs) and THP-1 cell line, used as systemic component models of COPD. We hypothesized that eHsp70 induces inflammation, but that it can also modulate cigarette smoke extract (CSE)-stimulated inflammatory responses. We assessed IL-8 secretion, TLR2, TLR4 and Hsp70 expressions, MAPKs and NF-κB activation, and cytotoxicity after treating the cells with CSE (2.5 and 5%) and its combinations with low-endotoxin recombinant human (rh) Hsp70, used to mimic eHsp70 effects. CSE induced IL-8 secretion from both cell types, but its combinations with rhHsp70 increased IL-8 release compared to CSE alone only from MDMs. In THP-1, combinations of rhHsp70 with 2.5% CSE induced TLR2 and TLR4 mRNA, while 5% CSE decreased TLR2 expression. In MDMs, CSE alone attenuated TLR2, while rhHsp70 increased TLR2 and lowered TLR4 gene expression. Hsp70 mRNA expression was suppressed in THP-1 with rhHsp70 and CSE; however, the same treatments increased its level in MDMs. CSE had cytotoxic effect only on MDMs, but cytotoxicity was reduced in co-treatments with rhHsp70, which also triggered apoptosis. CSE and rhHsp70 activated p38 and JNK, while ERK was activated only by rhHsp70 in MDMs. In THP-1, 2.5% CSE activated ERK, and 5% CSE activated p38. Inhibition of NF-κB and JNK in MDMs, and ERK and JNK in THP-1 cells, attenuated IL-8 release after rhHsp70 treatment. In conclusion, rhHsp70 provoked pro-inflammatory effects and could also modulate inflammatory response to CSE on protein and gene expression levels in THP-1 cells and MDMs, which suggests that eHsp70 might be implicated in systemic inflammation induced by cigarette smoke.

Determining the pharmacokinetics of nicotinic drugs in the endoplasmic reticulum using biosensors

Nicotine dependence is thought to arise in part because nicotine permeates into the endoplasmic reticulum (ER), where it binds to nicotinic receptors (nAChRs) and begins an "inside-out" pathway that leads to up-regulation of nAChRs on the plasma membrane. However, the dynamics of nicotine entry into the ER are unquantified. Here, we develop a family of genetically encoded fluorescent biosensors for nicotine, termed iNicSnFRs. The iNicSnFRs are fusions between two proteins: a circularly permutated GFP and a periplasmic choline-/betaine-binding protein engineered to bind nicotine. The biosensors iNicSnFR3a and iNicSnFR3b respond to nicotine by increasing fluorescence at [nicotine] <1 µM, the concentration in the plasma and cerebrospinal fluid of a smoker. We target iNicSnFR3 biosensors either to the plasma membrane or to the ER and measure nicotine kinetics in HeLa, SH-SY5Y, N2a, and HEK293 cell lines, as well as mouse hippocampal neurons and human stem cell-derived dopaminergic neurons. In all cell types, we find that nicotine equilibrates in the ER within 10 s (possibly within 1 s) of extracellular application and leaves as rapidly after removal from the extracellular solution. The [nicotine] in the ER is within twofold of the extracellular value. We use these data to run combined pharmacokinetic and pharmacodynamic simulations of human smoking. In the ER, the inside-out pathway begins when nicotine becomes a stabilizing pharmacological chaperone for some nAChR subtypes, even at concentrations as low as ∼10 nM. Such concentrations would persist during the 12 h of a typical smoker's day, continually activating the inside-out pathway by >75%. Reducing nicotine intake by 10-fold decreases activation to ∼20%. iNicSnFR3a and iNicSnFR3b also sense the smoking cessation drug varenicline, revealing that varenicline also permeates into the ER within seconds. Our iNicSnFRs enable optical subcellular pharmacokinetics for nicotine and varenicline during an early event in the inside-out pathway.

Concentration of Selected Elements in the Infrapatellar Fat Pad of Patients with a History of Total Knee Arthroplasty

In the period of long development, the human body adapted to specific concentrations of trace elements. Any changes in the trace element content manifesting in a deficiency or excess of metals in the human body may impair the functioning of the skeletal and articular system and of the organs, and may also predispose the body to the development of diseases, i.e., osteoporosis. Our study aimed to analyze the concentrations of calcium (Ca), magnesium (Mg), fluorides (F-), and lead (Pb) in the infrapatellar fat pad (Hoffa's fat pad) of subjects who had undergone a total knee replacement (TKR) surgery. We also endeavored to establish how concentration levels of those elements are affected by selected biological and environmental factors. The studied group comprised 48 residents of Western Pomerania Province: 34 women (n = 34) aged 56-87 and 12 men (n = 12) aged 59-85. Concentration levels of Ca, Mg, and Pb were established using inductively coupled plasma-atomic emission spectrometry (ICP-AES). A Thermo Orion ion-selective electrode was applied for measuring F- concentration. Subjects aged 75-87 showed higher Mg concentration values than those aged 56-74. Big city residents and smokers were found to have higher infrapatellar fat pad Mg concentration than their non-smoking counterparts and small town dwellers. Of all the elements whose concentrations we analyzed in our studies, only magnesium was found to correlate with smoking, place of residence, and age. Our findings regarding the quantities of selected elements in the infrapatellar fat pad may be used for the interpretation and analysis of biological, morphological, and mechanical changes in the human body.

SIPA1L3 methylation modifies the benefit of smoking cessation on lung adenocarcinoma survival: an epigenomic-smoking interaction analysis

Smoking cessation prolongs survival and decreases mortality of patients with non-small-cell lung cancer (NSCLC). In addition, epigenetic alterations of some genes are associated with survival. However, potential interactions between smoking cessation and epigenetics have not been assessed. Here, we conducted an epigenome-wide interaction analysis between DNA methylation and smoking cessation on NSCLC survival. We used a two-stage study design to identify DNA methylation-smoking cessation interactions that affect overall survival for early-stage NSCLC. The discovery phase contained NSCLC patients from Harvard, Spain, Norway, and Sweden. A histology-stratified Cox proportional hazards model adjusted for age, sex, clinical stage, and study center was used to test DNA methylation-smoking cessation interaction terms. Interactions with false discovery rate-q ≤ 0.05 were further confirmed in a validation phase using The Cancer Genome Atlas database. Histology-specific interactions were identified by stratification analysis in lung adenocarcinoma (LUAD) and lung squamous cell carcinoma (LUSC) patients. We identified one CpG probe (cg02268510SIPA1L3 ) that significantly and exclusively modified the effect of smoking cessation on survival in LUAD patients [hazard ratio (HR)interaction  = 1.12; 95% confidence interval (CI): 1.07-1.16; P = 4.30 × 10-7 ]. Further, the effect of smoking cessation on early-stage LUAD survival varied across patients with different methylation levels of cg02268510SIPA1L3 . Smoking cessation only benefited LUAD patients with low methylation (HR = 0.53; 95% CI: 0.34-0.82; P = 4.61 × 10-3 ) rather than medium or high methylation (HR = 1.21; 95% CI: 0.86-1.70; P = 0.266) of cg02268510SIPA1L3 . Moreover, there was an antagonistic interaction between elevated methylation of cg02268510SIPA1L3 and smoking cessation (HRinteraction  = 2.1835; 95% CI: 1.27-3.74; P = 4.46 × 10-3 ). In summary, smoking cessation benefited survival of LUAD patients with low methylation at cg02268510SIPA1L3 . The results have implications for not only smoking cessation after diagnosis, but also possible methylation-specific drug targeting.

The effect of body mass index on smoking behaviour and nicotine metabolism: a Mendelian randomization study

Given clear evidence that smoking lowers weight, it is possible that individuals with higher body mass index (BMI) smoke in order to lose or maintain their weight. We performed Mendelian randomization (MR) analyses of the effects of BMI on smoking behaviour in UK Biobank and the Tobacco and Genetics Consortium genome-wide association study (GWAS), on cotinine levels and nicotine metabolite ratio (NMR) in published GWAS and on DNA methylation in the Avon Longitudinal Study of Parents and Children. Our results indicate that higher BMI causally influences lifetime smoking, smoking initiation, smoking heaviness and also DNA methylation at the aryl-hydrocarbon receptor repressor (AHRR) locus, but we do not see evidence for an effect on smoking cessation. While there is no strong evidence that BMI causally influences cotinine levels, suggestive evidence for a negative causal influence on NMR may explain this. There is a causal effect of BMI on smoking, but the relationship is likely to be complex due to opposing effects on behaviour and metabolism.

A Review of A Priori Defined Oxidative Balance Scores Relative to Their Components and Impact on Health Outcomes

Oxidative Balance Scores (OBSs) are tools that have emerged to evaluate the global balance of individuals’ oxidation—reduction status. The aim was to compare OBSs available in the literature regarding their characteristics and associations with chronic diseases in epidemiological studies. Studies that developed OBSs were searched in PubMed until August 2018. A total of 21 OBSs were identified. These OBSs presented different scoring schemes and different types of anti- and pro-oxidant components, including dietary factors (dietary intake and/or nutrient biomarkers), lifestyle factors, and medications. Most OBSs were based on over 10 components, and some included only dietary factors. Few considered weighted components in the score. Only three OBSs were validated as potential surrogates of oxidative balance through inflammation and OS-related biomarkers. Notably, all the OBSs were associated—to a varying degree—with a reduced risk of cardiovascular diseases, chronic kidney disease, colorectal adenomas, and different cancer types (colorectal and breast cancer), as well as with all-cause and cancer-related mortality. For other outcomes, e.g., prostate cancer, contradictory results were reported. In summary, there is a great heterogeneity in the definition of OBSs. Most studies are concordant in supporting that excessive OS reflected by a lower OBS has deleterious effects on health. Unified criteria for defining the proper OBSs, valuable to gauge OS-related aspects of the diet and lifestyle that may lead to adverse health outcomes, are needed.

Biomedical risk assessment as an aid for smoking cessation

BACKGROUND

A possible strategy for increasing smoking cessation rates could be to provide smokers with feedback on the current or potential future biomedical effects of smoking using, for example, measurement of exhaled carbon monoxide (CO), lung function, or genetic susceptibility to lung cancer or other diseases.

OBJECTIVES

The main objective was to determine the efficacy of providing smokers with feedback on their exhaled CO measurement, spirometry results, atherosclerotic plaque imaging, and genetic susceptibility to smoking-related diseases in helping them to quit smoking.

SEARCH METHODS

For the most recent update, we searched the Cochrane Tobacco Addiction Group Specialized Register in March 2018 and ClinicalTrials.gov and the WHO ICTRP in September 2018 for studies added since the last update in 2012.

SELECTION CRITERIA

Inclusion criteria for the review were: a randomised controlled trial design; participants being current smokers; interventions based on a biomedical test to increase smoking cessation rates; control groups receiving all other components of intervention; and an outcome of smoking cessation rate at least six months after the start of the intervention.

DATA COLLECTION AND ANALYSIS

We used standard methodological procedures expected by Cochrane. We expressed results as a risk ratio (RR) for smoking cessation with 95% confidence intervals (CI). Where appropriate, we pooled studies using a Mantel-Haenszel random-effects method.

MAIN RESULTS

We included 20 trials using a variety of biomedical tests interventions; one trial included two interventions, for a total of 21 interventions. We included a total of 9262 participants, all of whom were adult smokers. All studies included both men and women adult smokers at different stages of change and motivation for smoking cessation. We judged all but three studies to be at high or unclear risk of bias in at least one domain. We pooled trials in three categories according to the type of biofeedback provided: feedback on risk exposure (five studies); feedback on smoking-related disease risk (five studies); and feedback on smoking-related harm (11 studies). There was no evidence of increased cessation rates from feedback on risk exposure, consisting mainly of feedback on CO measurement, in five pooled trials (RR 1.00, 95% CI 0.83 to 1.21; I2 = 0%; n = 2368). Feedback on smoking-related disease risk, including four studies testing feedback on genetic markers for cancer risk and one study with feedback on genetic markers for risk of Crohn's disease, did not show a benefit in smoking cessation (RR 0.80, 95% CI 0.63 to 1.01; I2 = 0%; n = 2064). Feedback on smoking-related harm, including nine studies testing spirometry with or without feedback on lung age and two studies on feedback on carotid ultrasound, also did not show a benefit (RR 1.26, 95% CI 0.99 to 1.61; I2 = 34%; n = 3314). Only one study directly compared multiple forms of measurement with a single form of measurement, and did not detect a significant difference in effect between measurement of CO plus genetic susceptibility to lung cancer and measurement of CO only (RR 0.82, 95% CI 0.43 to 1.56; n = 189).

AUTHORS' CONCLUSIONS

There is little evidence about the effects of biomedical risk assessment as an aid for smoking cessation. The most promising results relate to spirometry and carotid ultrasound, where moderate-certainty evidence, limited by imprecision and risk of bias, did not detect a statistically significant benefit, but confidence intervals very narrowly missed one, and the point estimate favoured the intervention. A sensitivity analysis removing those studies at high risk of bias did detect a benefit. Moderate-certainty evidence limited by risk of bias did not detect an effect of feedback on smoking exposure by CO monitoring. Low-certainty evidence, limited by risk of bias and imprecision, did not detect a benefit from feedback on smoking-related risk by genetic marker testing. There is insufficient evidence with which to evaluate the hypothesis that multiple types of assessment are more effective than single forms of assessment.

The effect of nonsurgical periodontal therapy on pentraxin 3 levels in smokers and nonsmokers with chronic periodontitis

The purpose of this study was to determine the pentraxin 3 (PTX3) levels in the gingival crevicular fluid (GCF) and saliva of smokers and nonsmokers with chronic periodontitis and to compare these levels before and after initial nonsurgical periodontal therapy. Forty subjects were divided into 2 groups with chronic periodontitis (smokers and nonsmokers) and 2 clinically healthy groups (smokers and nonsmokers). At baseline, clinical periodontal parameters, including plaque index, gingival index, probing depth, and clinical attachment levels, were assessed. Saliva and GCF samples were procured to quantify the PTX3 levels. All subjects with periodontitis, smokers and nonsmokers, received scaling and root planing. The 2 treated groups were examined 2 weeks after therapy, and any changes in the clinical parameters or PTX3 levels were recorded. At baseline, PTX3 levels in both groups of patients with chronic periodontitis were found to be significantly higher (smokers had the highest level, followed by nonsmokers) than levels in both groups of clinically healthy subjects (nonsmokers, followed by smokers) (P < 0.05). Five patients with chronic periodontitis (3 smokers and 2 nonsmokers) were lost to follow-up and therefore excluded from the statistical analysis. Scaling and root planing led to an improvement in the clinical parameters and a statistically significant reduction of PTX3 levels (P < 0.05) in both chronic periodontitis groups at the 2-week follow-up, but the changes were greater in the smokers than in the nonsmokers. In the present study, smoking was found to play a contributory role in the alteration of PTX3 levels in GCF and saliva in patients with chronic periodontitis. The role of PTX3 as a prognostic tool for resolution of periodontal inflammation still remains obscure.

Continuous exposure of nicotine and cotinine retards human primary pterygium cell proliferation and migration

Pterygium is a triangular-shaped hyperplastic growth, characterized by conjunctivalization, inflammation, and connective tissue remodeling. Our previous meta-analysis found that cigarette smoking is associated with a reduced risk of pterygium. Yet, the biological effect of cigarette smoke components on pterygium has not been studied. Here we reported the proliferation and migration properties of human primary pterygium cells with continuous exposure to nicotine and cotinine. Human primary pterygium cells predominantly expressed the α5, β1, and γ subunits of the nicotinic acetylcholine receptor. Continuous exposure to the mixture of 0.15 μM nicotine and 2 μM cotinine retarded pterygium cell proliferation by 16.04% (P = 0.009) and hindered their migration by 11.93% ( P = 0.039), without affecting cell apoptosis. SNAIL and α-smooth muscle actin protein expression was significantly downregulated in pterygium cells treated with 0.15 μM nicotine-2 μM cotinine mixture by 1.33- ( P = 0.036) and 1.31-fold ( P = 0.001), respectively. Besides, the 0.15 μM nicotine-2 μM cotinine mixture also reduced matrix metalloproteinase (MMP)-1 and MMP-9 expressions in pterygium cells by 1.56- ( P = 0.043) and 1.27-fold ( P = 0.012), respectively. In summary, this study revealed that continuous exposure of nicotine and cotinine inhibited human primary pterygium cell proliferation and migration in vitro by reducing epithelial-to-mesenchymal transition and MMP protein expression, partially explaining the lower incidence of pterygium in cigarette smokers.

BAMBI regulates macrophages inducing the differentiation of Treg through the TGF-β pathway in chronic obstructive pulmonary disease

BACKGROUND

Chronic obstructive pulmonary disease (COPD) is characterized by continuous flow limitation and the immune system including macrophages and regulatory T lymphocytes (Tregs) is involved in COPD pathogenesis. In our previous study, we investigated that TGF-β/BAMBI pathway was associated with COPD by regulating the balance of Th17/Treg. However, the role of bone morphogenetic protein and activin membrane-bound inhibitor (BAMBI), a pseudoreceptor of TGF-β signalling pathway, in regulating the immune system of COPD patients has not been fully studied. Hence, we speculate that the pseudoreceptor BAMBI may play roles in the regulation of M2 macrophages to induce the differentiation of CD4+ naïve T cells into Tregs and influence the immune response in COPD.

METHODS

Peripheral blood mononuclear cells (PBMCs) were isolated from healthy nonsmokers (n = 12), healthy smokers (n = 10) and COPD patients (n = 20). Naïve CD4+ T cells and monocytes-induced macrophages were used for coculture assays. The phenotypic characteristics of macrophages and Tregs were determined by flow cytometry. The expression levels of BAMBI and the TGF-β/Smad pathway members in M2 macrophages were measured by a Western blot analysis. The monocyte-derived macrophages were stimulated with cigarette smoke extract (CSE, concentration of 0.02%) to simulate the smoking process in humans. pCMV-BAMBI was transfected into monocyte-derived M2 macrophages for subsequent co-culture assays and signalling pathway analysis.

RESULTS

Our results showed that M2 macrophages could induce the differentiation of Tregs through the TGF-β/Smad signalling pathway. In addition, monocyte-derived macrophages from COPD patients highly expressed BAMBI, and had a low capacity to induce Tregs differentiation. The expression of BAMBI and the forced expiratory volume in 1 second (FEV1%) were negatively correlated in COPD. Furthermore, overexpression of BAMBI promoted the conversion of M2 macrophages to M1 macrophages via the TGF-β/Smad pathway.

CONCLUSIONS

We demonstrated that BAMBI could promote the polarization process of M2 macrophages to M1 macrophages via the TGF-β/Smad signalling pathway and that overexpression of BAMBI could decrease the ability of M2 macrophages to induce Treg differentiation. These findings may provide a potential mechanism by which blocking BAMBI could improve immune function to regulate COPD inflammatory conditions.

Brief Report: Rate of Nicotine Metabolism and Tobacco Use Among Persons With HIV: Implications for Treatment and Research

BACKGROUND

The nicotine metabolite ratio (NMR) is a biomarker that represents individual variation in the speed that nicotine is metabolized. The rate of nicotine metabolism alters smoking behavior (eg, amount) and has been validated for personalizing tobacco dependence medication selection to increase treatment efficacy and reduce treatment side effects in the general population of smokers. Although smoking rates are extremely high among those with HIV, the NMR has not been evaluated in this underserved population.

METHODS

We used baseline data from a smoking cessation clinical trial for smokers with HIV (N = 131) to examine associations between NMR and demographic, smoking, disease-related, and psychological characteristics. Pearson r and analysis of variance were used to identify univariate correlates of NMR, which were then entered into a multiple linear regression model.

RESULTS

In univariate analyses, a higher NMR (faster nicotine metabolism) was associated with being white, and more cigarettes per day, nicotine dependence, exhaled carbon monoxide, and symptoms of depression and anxiety, and using efavirenz. In a multiple regression model, a higher NMR was associated with more cigarettes per day, higher anxiety symptoms, and efavirenz use.

CONCLUSIONS

As in other populations, faster nicotine metabolism was associated with the use of more cigarettes and higher anxiety symptoms. Notably, efavirenz use was associated with faster metabolism, which might make it harder to quit smoking for people with HIV treated with that medication. These findings could help guide further study and the clinical use of the NMR to personalize nicotine dependence treatment in this underserved population.

Tobacco Heating System 2.2 has a limited impact on DNA methylation of candidate enhancers in mouse lung compared with cigarette smoke

Cigarette smoke (CS) exposure has been shown to correlate with changes in DNA methylation levels, however, the impact of CS on DNA methylation at genome-wide scale is missing. Here, we used whole-genome bisulfite sequencing to assess the effects of CS extract and aerosol from the Tobacco Heating System (THS) 2.2, a candidate modified risk tobacco product, on DNA methylation in lung and liver tissues from apolipoprotein E-deficient mice during an eight-month period of exposure. We found that in lung tissue, CS mainly induced hypermethylation of candidate enhancers at late time points, while promoters were less affected. This effect was strongly reduced upon cessation or switching to THS 2.2. By contrast, chronic exposure to THS 2.2 had a limited effect on DNA methylation at both promoters and enhancers. We also identified members of the Ets and Fox families of transcription factors as potential players in the epigenetic response to CS exposure in lung tissue. In contrast to the lung, DNA methylation in the liver was largely insensitive to all investigated exposures. In summary, our investigations indicate that CS-related DNA methylation alterations are tissue-specific, occur mainly at enhancers and are strongly reduced upon smoking cessation or switching to THS2.2.

Effects of smoking on the lower respiratory tract microbiome in mice

BACKGROUND

Recent studies break with traditional opinion that the lower respiratory tract is sterile, and increasingly focus on the lung microbiome and disease. Smoking, as an important etiology of inflammatory lung disease, was considered as a factor influencing lung microbiome variations in our study, and we aimed to study the effect of smoking on inflammation and microbial diversity and community.

METHODS

Forty male mice were selected and randomly divided into a smoking and a non-smoking group. Mice in the smoking group were exposed to smoke smog for 2 h/day for 90 days. Blood and lung tissues were obtained after the experiment, and ELISA was used to measure interleukin-6 and C reactive protein concentrations. 16S rRNA gene quantification and sequencing technology were used to compare microbial diversity and community between the two groups. SAS 9.1 and R software were used to analyze the data.

RESULTS

Thirty-six mice survived, and the weight of the smoking group increased more slowly than that of the non-smoking group. Denser inflammation and congestion were observed in the lungs of the smoking mice compared with the non-smoking group Higher microbial diversity was observed in the smoking group, and Enterobacter, Acidimicrobiales_norank, and Caulobacteraceae_Unclassified genus were significantly more abundant in the non-smoking group (P < 0.001).

CONCLUSIONS

Smoking altered microbial diversities and communities in the lower respiratory tract of mice. Microbial variation should be considered in future studies focusing on smoking-induced inflammatory disease.

Expression levels of miR-34-family microRNAs are associated with TP53 mutation status in head and neck squamous cell carcinoma

PURPOSE

The majority of head and neck squamous cell carcinoma (HNSCC) cases in developing countries are associated with cigarette smoking and TP53 mutations. p53 is a transcription factor that activates downstream genes, including the hsa-miR-34a and hsa-miR-34b/c loci, to achieve cell-cycle arrest, senescence, and/or apoptosis. This study examined the differences in expression levels of miR-34 in HNSCC with or without TP53 mutations.

METHODS

We examined surgically resected tumor samples and normal adjacent tissues from HNSCC in oral cavity, larynx, and hypopharynx for TP53 mutations (exons 5-8) and miR-34 expression levels.

RESULTS

miR-34a, miR-34b, miR-34b*, and miR-34c are significantly up-regulated in tumors with wild-type TP53 genes (n = 23); while such up-regulation is not observed in tumors with mutant TP53 (n = 19). Although expression levels of miR-34-family miRNAs do not correlate with gender, age, or tumor staging, interestingly they are correlated with smoking status and tumor sites. miR-34b/b*/c are up-regulated in tumors from those who ever smoked or recently smoked (quit smoking less than 15 years ago); but such up-regulation was not seen in those who never smoked or quit smoking for at least 15 years. HNSCC of the oral cavity also up-regulated miR-34b/b*/c while no such overexpression was observed in HNSCC of the larynx and hypopharynx.

CONCLUSIONS

Surgically resected HNSCC samples with no TP53 mutations have elevated levels of miR-34a and miR-34b/b*/c, while those with TP53 mutations show no such up-regulation. miR-34b/b*/c expression is also correlated with smoking status and tumor sites.

Differential expression of heat shock proteins and activation of mitogen-activated protein kinases in A549 alveolar epithelial cells exposed to cigarette smoke extract

NEW FINDINGS

What is the central question of this study? What is the effect of cigarette smoke on cell death, oxidative damage, expression of heat shock proteins (HSPs) and activation of mitogen-activated protein kinases (MAPKs) in A549 alveolar epithelial cells? What is the main finding and its importance? Cigarette smoke induces cytotoxicity and oxidative damage to A549 cells, increases expression of different HSPs and activates MAPK signalling pathways. This could be related to inflammatory response and apoptosis observed in lungs of patients with smoking-related diseases.

ABSTRACT

Cigarette smoking is one of the main risk factors for development of chronic obstructive pulmonary disease (COPD). We previously reported that cigarette smoke (CS) induces damage to proteins and their ineffective degradation. Here, we hypothesize that CS could induce oxidative stress and cytotoxicity in lung epithelial cells through alterations of heat shock protein (HSP) expression and mitogen-activated protein kinase (MAPK) signalling pathways. We exposed A549 alveolar epithelial cells to various concentrations of cigarette smoke extract (CSE). Higher concentrations of CSE caused apoptosis of A549 cells after 4 h, while after 24 h cell viability was decreased, and lactate dehydrogenase in cell culture medium was increased as well as the number of necrotic cells. Concentrations of malondialdehyde (MDA) were elevated, while total thiol groups were decreased. Changes in the expression of HSPs (HSP70, HSP32 and HSP27) were time-dependent. After 6 h, CSE caused an increase in the expression of HSP70 and HSP32, while after 8 h all examined HSPs were up-regulated and remained increased up to 48 h. Treatment of A549 cells with CSE stimulated phosphorylation of extracellular signal-regulated kinase and p38 in a dose-dependent manner, while c-Jun N-terminal kinase activation was not detected. By using specific inhibitors, we demonstrated that MAPKs and HSPs interplay in CSE effects. In conclusion, our results show that MAPKs and HSPs are involved in the mechanism underlying CSE-induced cytotoxicity and oxidative damage to A549 alveolar epithelial cells. These processes could be related to inflammatory response and apoptosis observed in lungs of patients with smoking-related diseases, such as COPD.