In vitro assessment of reproductive toxicity of tobacco smoke and its constituents

Maternal Cigarette Smoking and Congenital Upper and Lower Limb Differences: A Systematic Review and Meta-Analysis

Maternal smoking during pregnancy has been associated with adverse effects on foetal development, including congenital limb anomalies. This systematic review aimed to provide an updated assessment of the association between maternal smoking during pregnancy and the risk of congenital limb anomalies. A systematic search was conducted to identify relevant studies published up to February 2023. Studies reporting on the relationship between maternal smoking during pregnancy and congenital digital anomalies or congenital limb reduction defects were included. Two independent reviewers screened the studies, extracted data, and assessed the quality of the included studies. Meta-analyses were performed to estimate the pooled odds ratios with 95% confidence intervals using fixed and random-effects models. In total, 37 publications comprising 11 cohort and 26 case-control studies were included in the systematic review. The meta-analysis demonstrated a significant increased risk of congenital limb reduction defects (pooled OR: 1.27, 95% CI: 1.18-1.38) in infants born to mothers who smoked during pregnancy. Similarly, a significant relationship was observed for the development of polydactyly/syndactyly/adactyly when considered as a single group (pooled OR: 1.32, 95% CI: 1.25-1.40). Yet, in contrast, no significant association was observed when polydactyly (pooled OR: 1.06, 95% CI: 0.88-1.27) or syndactyly (pooled OR: 0.91, 95% CI: 0.77-1.08) were considered individually. This systematic review provides updated evidence of a significant relationship between maternal smoking during pregnancy and increased risk of congenital limb anomalies. These findings highlight the potential detrimental effects of smoking on foetal limb development and underscore the importance of smoking cessation interventions for pregnant women to mitigate these risks.

Factors affecting the distribution of serum anti-müllerian hormone levels among infertile Asian women: a multi-nation, multi-centre, and multi-ethnicity prospective cohort study

STUDY QUESTION

How do age, ethnicity, and other characteristics affect serum anti-mullerian hormone (AMH) levels in Asian women undergoing fertility treatment?

SUMMARY ANSWER

Age, ethnicity, obesity (BMI ≥ 30 kg/m2), and polycystic ovarian syndrome (PCOS) significantly impacted serum AMH levels, with the rate of decrease accelerating as age increased; a concentration of 4.0 ng/ml was the optimal cut-off for diagnosis of PCOS.

WHAT IS KNOWN ALREADY

There are significant differences in ovarian reserve among women from different races and ethnicities, and Asian women often have poorer reproductive outcomes during assisted reproductive treatment cycles.

STUDY DESIGN, SIZE, DURATION

A population-based multi-nation, multi-centre, multi-ethnicity prospective cohort study of 4613 women was conducted from January 2020 to May 2021. Infertile women of 20-43 years of age were enrolled. The exclusion criteria included: age <20 or >43, non-Asian ethnicity, and missing critical data.

PARTICIPANTS/MATERIALS, SETTING, METHODS

Participants were Asian women of Chinese, Japanese, Korean, Thai, Vietnamese, Malay, Indian, and Indonesian ethnicities from 12 IVF centres across Asia. These women were all naïve to ovarian stimulation cycles and attended IVF centres for fertility assessment. The AMH measurement was performed using an AMH automated assay on a clinically validated platform.

MAIN RESULTS AND THE ROLE OF CHANCE

A total of 4556 infertile Asian women were included in the final analyses. The mean ± SD for serum AMH concentrations (ng/ml) across specific age groups were: overall, 3.44 ± 2.93; age <30, 4.58 ± 3.16; 30-31, 4.23 ± 3.23; 32-33, 3.90 ± 3.06; 34-35, 3.21 ± 2.65; 36-37, 2.74 ± 2.44; 38-39, 2.30 ± 1.91; 40 and above, 1.67 ± 2.00. The rate of AMH decrease was ∼0.13 ng/ml/year in patients aged 25-33 and 0.31 ng/ml/year in women aged 33-43. The highest rates of PCOS were found in Indians (18.6%), Malays (18.9%), and Vietnamese (17.7%). Age (P < 0.001), ethnicity (P < 0.001), obesity (P = 0.007), PCOS (P < 0.001), and a history of endometrioma cystectomy (P = 0.01) were significantly associated with serum AMH values. Smoking status, pretreatment with GnRH agonist (GnRHa) or the oral contraceptive pill (OCP), freezing-thawing of blood samples, and sampling on Day 2 to Day 5 of the menstrual cycle or randomly did not appear to affect serum AMH levels. An AMH concentration of 4.0 ng/ml was the optimal cut-off for PCOS diagnosis with a sensitivity of 71.7% and specificity of 75.8% (AUC = 0.81, CI 95%: 0.79-0.83; P < 0.001).

LIMITATIONS, REASONS FOR CAUTION

The incidence of PCOS was supposedly high in this cohort as some IVF clinics were tertiary referral centres for managing specific fertility issues encountered by women with PCOS. Treatment with GnRHa or OCP before AMH testing was regionally and ethnically confined, mostly in Hong Kong SAR and Japan. Moreover, this reference for serum AMH value is limited to Asian women of the ethnicities examined and may not apply to other ethnicities not included in the study.

WIDER IMPLICATIONS OF THE FINDINGS

This is the first study to collate and construct age-specific reference ranges for serum AMH levels using the same bioassay on Asian women of different ethnicities. The findings of this investigation can assist clinicians to counsel and prognosticate about Asian women's ovarian reserve and reproductive potential, thus providing better strategies for personalized fertility interventions.

STUDY FUNDING/COMPETING INTEREST(S)

This study was technically supported by Ferring Pharmaceuticals and received no specific grant from any funding agency. All authors have no competing interests to disclose.

TRIAL REGISTRATION NUMBER

NCT04203355.

Parental smoking and risk of hypospadias: An updated meta-analysis of observational studies

Background

Inconsistent relationships have been shown between cigarette smoking and hypospadias in offspring. The purpose of this study was to summarize epidemiological evidence to evaluate the relationship between parental smoking and the risk of hypospadias.

Methods

Up until October 2022, PubMed, EMBASE, Web of Science, and the Cochrane Library were systematically searched for qualified research. The summary RRs and 95% CIs were calculated using either a fixed-effects or a random-effects model. There were subgroup analyses undertaken to identify potential sources of heterogeneity.

Results

44 studies with 16,637,830 participants were included in our meta-analysis. Overall, maternal active smoking [risk ratio (RR) = 0.94; 95% confidence interval (CI): 0.90-0.99; P < 0.01] was significantly associated with the risk of hypospadias. And neither paternal smoking (RR = 1.00; 95% CI: 0.86-1.15) nor maternal passive smoking (RR = 0.91; 95% CI: 0.60-1.23) was associated with the risk of hypospadias.

Conclusion

Our study discovered an association between maternal active smoking and a decreased risk of hypospadias, which may be due to the effect of smoking on androgen. However, as numerous studies have proved that cigarette smoking during pregnancy increases the risk of overall birth abnormalities in offspring, quitting cigarettes before pregnancy positively influences the health of offspring and should be advocated worldwide.

Systematic review registration

[www.crd.york.ac.uk/prospero], identifier [CRD42022319378].

DNA damage, DNA repair and carcinogenicity: Tobacco smoke versus electronic cigarette aerosol

The allure of tobacco smoking is linked to the instant gratification provided by inhaled nicotine. Unfortunately, tobacco curing and burning generates many mutagens including more than 70 carcinogens. There are two types of mutagens and carcinogens in tobacco smoke (TS): direct DNA damaging carcinogens and procarcinogens, which require metabolic activation to become DNA damaging. Recent studies provide three new insights on TS-induced DNA damage. First, two major types of TS DNA damage are induced by direct carcinogen aldehydes, cyclic-1,N2-hydroxy-deoxyguanosine (γ-OH-PdG) and α-methyl-1, N2-γ-OH-PdG, rather than by the procarcinogens, polycyclic aromatic hydrocarbons and aromatic amines. Second, TS reduces DNA repair proteins and activity levels. TS aldehydes also prevent procarcinogen activation. Based on these findings, we propose that aldehydes are major sources of TS induce DNA damage and a driving force for carcinogenesis. E-cigarettes (E-cigs) are designed to deliver nicotine in an aerosol state, without burning tobacco. E-cigarette aerosols (ECAs) contain nicotine, propylene glycol and vegetable glycerin. ECAs induce O6-methyl-deoxyguanosines (O6-medG) and cyclic γ-hydroxy-1,N2--propano-dG (γ-OH-PdG) in mouse lung, heart and bladder tissues and causes a reduction of DNA repair proteins and activity in lungs. Nicotine and nicotine-derived nitrosamine ketone (NNK) induce the same types of DNA adducts and cause DNA repair inhibition in human cells. After long-term exposure, ECAs induce lung adenocarcinoma and bladder urothelial hyperplasia in mice. We propose that E-cig nicotine can be nitrosated in mouse and human cells becoming nitrosamines, thereby causing two carcinogenic effects, induction of DNA damage and inhibition of DNA repair, and that ECA is carcinogenic in mice. Thus, this article reviews the newest literature on DNA adducts and DNA repair inhibition induced by nicotine and ECAs in mice and cultured human cells, and provides insights into ECA carcinogenicity in mice.

Second hand smoking and tobacco use among pregnant women in Yatinuwara Medical Officer of Health (MOH) area in Sri Lanka

This study was aimed to assess the prevalence and factors associated with second hand smoking (SHS) and tobacco use among pregnant women in Yatinuwara Medical Officer of Health area in Kandy district, Sri Lanka. This was a descriptive cross-sectional study using 390 pregnant women. Data were collected through a pre-tested, self-administered questionnaire. Fifty-four-point four percent were exposed to the SHS. Prevalence of smoking during pregnancy was 0.5% and eight women used smokeless tobacco (SLT). SHS was significantly associated with the age of the mother and family income. Women's age, monthly income, husband's education, husband's occupation, women's age at marriage and trimester of pregnancy were significantly associated with tobacco use. In conclusions, prevalence of SHS was high but tobacco use was low in pregnant women. An effective training program should be designed to educate pregnant women as well as their husbands on adverse effects of tobacco use and SHS during pregnancy.

Nicotine and Its Downstream Metabolites in Maternal and Cord Sera: Biomarkers of Prenatal Smoking Exposure Associated with Offspring DNA Methylation

Nicotine is a major constituent of cigarette smoke. Its primary metabolite in maternal and cord sera, cotinine, is considered a biomarker of prenatal smoking. Nicotine and cotinine half-lives are decreased in pregnancy due to their increased rate of metabolism and conversion to downstream metabolites such as norcotinine and 3-hydroxycotinine. Hence, downstream metabolites of nicotine may provide informative biomarkers of prenatal smoking. In this study of three generations (F0-mothers, F1-offspring who became mothers, and F2-offspring), we present a biochemical assessment of prenatal smoking exposure based on maternal and cord sera levels of nicotine, cotinine, norcotinine, and 3-hydroxycotinine. As potential markers of early effects of prenatal smoking, associations with differential DNA methylation (DNAm) in the F1- and F2-offspring were assessed. All metabolites in maternal and cord sera were associated with self-reported prenatal smoking, except for nicotine. We compared maternal self-report of smoking in pregnancy to biochemical evidence of prenatal smoking exposure. Self-report of F0-mothers of F1 in 1989–1990 had more accuracy identifying prenatal smoking related to maternal metabolites in maternal serum (sensitivity = 94.6%, specificity = 86.9%) compared to self-reports of F1-mothers of F2 (2010–2016) associated with cord serum markers (sensitivity = 66.7%, specificity = 78.8%). Nicotine levels in sera showed no significant association with any DNAm site previously linked to maternal smoking. Its downstream metabolites, however, were associated with DNAm sites located on the MYO1G, AHRR, and GFI1 genes. In conclusion, cotinine, norcotinine, and 3-hydroxycotinine in maternal and cord sera provide informative biomarkers and should be considered when assessing prenatal smoking. The observed association of offspring DNAm with metabolites, except for nicotine, may imply that the toxic effects of prenatal nicotine exposure are exerted by downstream metabolites, rather than nicotine. If differential DNA methylation on the MYO1G, AHRR, and GFI1 genes transmit adverse effects of prenatal nicotine exposure to the child, there is a need to investigate whether preventing changes in DNA methylation by reducing the metabolic rate of nicotine and conversion to harmful metabolites may protect exposed children.

Prenatal toxicity of the environmental pollutants on neuronal and cardiac development derived from embryonic stem cells

Pesticides, antibiotics, and industrial excipients are widely used in agriculture, medicine, and chemical industry, respectively. They often end up in the environment, not only being not easily decomposed but also being accumulated. Moreover, they may cause serious toxic problems such as reproductive and developmental defects, immunological toxicity, and carcinogenesis. Hence, they are called environmental pollutants. It is known that the environmental pollutants easily enter the body through various channels such as respiration, ingestion of food, and skin contact etc. in everyday life. If they enter the mother through the placenta, they can cause the disturbance in embryo development as well as malfunction of organs after birth because early prenatal developmental process is highly sensitive to toxic chemicals and stress. Embryonic stem cells (ESCs) that consist of inner cell mass of blastocyst differentiate into distinct cell lineages via three germ layers such as the ectoderm, mesoderm, and endoderm due to their pluripotency. The differentiation process initiated from ESCs reflects dynamic nature of embryonic development. Therefore, ESCs have been used as a useful tool to investigate early developmental toxicities of a variety of stress. Based on relatively recent scientific results, this review would address toxicity of a few chemical substances that have been widely used as pesticide, antibiotics, and industrial excipient on ESCs based-prenatal developmental process. This review further suggests how they act on the viability of ESCs and/or early stages of cardiac and neuronal development derived from ESCs as well as on expression of pluripotency and/or differentiation markers through diverse mechanisms.

Mitochondrial Stress Response in Neural Stem Cells Exposed to Electronic Cigarettes

Stem cells provide a sensitive model to study exposure to toxicants, such as cigarette smoke. Electronic cigarettes (ECs) are popular nicotine delivery devices, often targeted to youth and pregnant mothers. However, little is known about how chemicals in ECs might affect neural stem cells, and in particular their mitochondria, organelles that maintain cell functionality and health. Here we show that the mechanism underlying EC-induced stem cell toxicity is stress-induced mitochondrial hyperfusion (SIMH), a transient survival response accompanied by increased mitochondrial oxidative stress. We identify SIMH as a survival response to nicotine, now widely available in EC refill fluids and in pure form for do-it-yourself EC products. These observed mitochondrial alterations combined with autophagy dysfunction to clear damaged mitochondria could lead to faulty stem cell populations, accelerate cellular aging, and lead to acquired mitochondriopathies. Any nicotine-containing product may likewise stress stem cells with long-term repercussions for users and passively exposed individuals. VIDEO ABSTRACT.

Assessment of Toxic Effects of Ochratoxin A in Human Embryonic Stem Cells

Ochratoxin A (OTA) is a mycotoxin produced by different Aspergillus and Penicillium species, and it is considered a common contaminant in food and animal feed worldwide. On the other hand, human embryonic stem cells (hESCs) have been suggested as a valuable model for evaluating drug embryotoxicity. In this study, we have evaluated potentially toxic effects of OTA in hESCs. By using in vitro culture techniques, specific cellular markers, and molecular biology procedures, we found that OTA produces mild cytotoxic effects in hESCs by inhibiting cell attachment, survival, and proliferation in a dose-dependent manner. Thus, we suggest that hESCs provide a valuable human and cellular model for toxicological studies regarding preimplantation stage of human fetal development.

Fate of pyrazines in the flavored liquids of e-cigarettes

Popularity of electronic cigarettes (ECIGs) has increased tremendously among young people, in part due to flavoring additives in ECIG liquids. Pyrazines are an important class of these additives, and their presence in tobacco cigarettes has been correlated with increased acceptability of smoking among smokers and bystanders. Pyrazine use by the tobacco industry is therefore thought to encourage smoking. However, the extent of transfer of pyrazines present in the liquid to aerosols upon vaping remains unclear. We present a simple analytical method to quantify six pyrazine derivatives in liquids and aerosols of ECIGs that allows the isolation of pyrazines from interfering compounds, like nicotine. Standard pyrazine solutions and commercial ECIG samples of different brands and flavors were tested for their pyrazine content in the liquids and in the generated aerosols from these solutions. Testing on ECIG commercial liquids revealed a heterogeneous distribution in the levels and types of pyrazines, with acetyl and alkyl pyrazines present in more than 70% of the samples. This method confirmed that pyrazine additives are common in ECIG and that labels do not usually reflect the type and quantity of pyrazines in the liquid. Pyrazines were not correlated with the nicotine content or the brand of the liquid. The aerosols showed similar pyrazine profiles to their corresponding liquids. The efficiency of transfer of pyrazines into the particle phase was approximately 46%. Therefore, addition of pyrazines to ECIGs should be regulated, because they act synergistically with nicotine to increase product appeal, ease smoking initiation, and discourage cessation.

Childhood secondhand smoke exposure and pregnancy loss in never smokers: the Guangzhou Biobank Cohort Study

OBJECTIVE

Studies of secondhand smoke (SHS) exposure especially childhood SHS exposure and pregnancy loss are limited. We used baseline data of the Guangzhou Biobank Cohort Study (GBCS) to examine the association of childhood SHS exposure with a history of pregnancy loss.

METHODS

Never smoking women aged 50 years or above in GBCS from 2003 to 2008 were included. Propensity score matching (PSM) was used to control for confounding. Negative binomial regression and logistic regression were used to examine the association of childhood SHS, assessed by number of smokers in childhood household and frequency of exposure, with past pregnancy loss.

RESULTS

Of 19 562 women, 56.7% (11 096) had SHS exposure during childhood. In negative binomial regression, after adjusting for age, education, past occupational dust exposure, past home fuel exposure, oral contraceptive, adulthood SHS exposure, age at first pregnancy and age at first menarche, compared to non-exposure, the incidence rate ratio of one more pregnancy loss was 1.20 (95% CI1.05 to 1.37) in those who lived with ≥2 smokers in the same household, and 1.14 (95% CI 1.04 to 1.25) in those exposed ≥5 times/week. After similar adjustment, logistic regression showed that the OR of pregnancy loss ≥2 times (versus 0 to 1 time) was 1.25 (95% CI 1.00 to 1.57) and 1.20 (95% CI 1.03 to 1.40) for high density (≥2 smokers in the same household) and frequency (≥5 times/week) of childhood exposure, respectively.

CONCLUSIONS

Childhood SHS exposure was associated with higher risks of pregnancy loss in middle-aged and older Chinese women.

Thirdhand Smoke: New Evidence, Challenges, and Future Directions

Thirdhand smoke (THS) is the contamination that persists after secondhand tobacco smoke has been emitted into air. It refers to the tobacco-related gases and particles that become embedded in materials, such as the carpet, walls, furniture, blankets, and toys. THS is not strictly smoke, but chemicals that adhere to surfaces from which they can be released back into the air, undergo chemical transformations and/or accumulate. Currently, the hazards of THS are not as well documented as the hazards of secondhand smoke (SHS). In this Perspective, we describe the distribution and chemical changes that occur as SHS is transformed into THS, studies of environmental contamination by THS, human exposure studies, toxicology studies using animal models and in vitro systems, possible approaches for avoiding exposure, remediation of THS contamination, and priorities for further research.

Cytotoxicity of Thirdhand Smoke and Identification of Acrolein as a Volatile Thirdhand Smoke Chemical That Inhibits Cell Proliferation

Thirdhand smoke (THS) is a mixture of chemicals that remain on indoor surfaces after smoking has ceased. These chemicals can be inhaled, ingested, or absorbed dermally, and thus could impact human health. We evaluated the cytotoxicity and mode of action of fresh and aged THS, the toxicity of volatile organic chemicals (VOCs) in THS, and the molecular targets of acrolein, a VOC in THS. Experiments were done using mouse neural stem cells (mNSC), human pulmonary fibroblasts (hPF), and lung A549 epithelial cells. THS-exposed cotton cloth was extracted in Dulbecco's Eagle Medium and caused cytotoxicity in the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. THS extracts induced blebbing, immotility, vacuolization, cell fragmentation, severing of microfilaments and depolymerization of microtubules in mNSC. Cytotoxicity was inversely related to headspace volume in the extraction container and was lost upon aging, suggesting that VOCs in THS were cytotoxic. Phenol, 2',5'-dimethyl furan and acrolein were identified as the most cytotoxic VOCs in THS, and in combination, their cytotoxicity increased. Acrolein inhibited proliferation of mNSC and hPF and altered expression of cell cycle regulatory genes. Twenty-four hours of treatment with acrolein decreased expression of transcription factor Dp-1, a factor needed for the G1 to S transition in the cell cycle. At 48 h, WEE1 expression increased, while ANACP1 expression decreased consistent with blocking entry into and completion of the M phase of the cell cycle. This study identified acrolein as a highly cytotoxic VOC in THS which killed cells at high doses and inhibited cell proliferation at low doses.

Thirdhand smoke: Chemical dynamics, cytotoxicity, and genotoxicity in outdoor and indoor environments

We tested the toxicity of thirdhand smoke (THS) using two controlled laboratory exposure scenarios and low levels of THS. One exposure modeled THS in a car parked outdoors, while the second modeled THS in a room without sunlight. The fabrics were exposed to cigarette smoke and then extracted in culture medium. Concentrations of nicotine, nicotine related alkaloids, and tobacco specific nitrosamines (TSNAs) were determined in fresh and aged extracts. The concentration of TSNAs increased with aging in the indoor experiment. THS extracts were used for cytotoxicity testing using mouse neural stem cells (mNSC), human dermal fibroblasts (hDF) and human palatal mesenchyme cells (hPM). Extracts from the car experiment inhibited mNSC proliferation in a live cell imaging assay and induced single strand DNA breaks in mNSC and hDF. In the indoor experiment, THS extracts made with medium containing serum proteins were significantly more toxic than extracts made with basal medium, and mNSC and hPM were more sensitive than hDF. These data indicate that: (1) aging of THS chemical differs on different fabrics and differs with and without sunlight; (2) very few cigarettes are sufficient to produce a toxic THS residue; and (3) protein enhances the efficiency of extraction of cytotoxic chemicals.

Cigarette side-stream smoke lung and bladder carcinogenesis: inducing mutagenic acrolein-DNA adducts, inhibiting DNA repair and enhancing anchorage-independent-growth cell transformation

Second-hand smoke (SHS) is associated with 20-30% of cigarette-smoke related diseases, including cancer. Majority of SHS (>80%) originates from side-stream smoke (SSS). Compared to mainstream smoke, SSS contains more tumorigenic polycyclic aromatic hydrocarbons and acrolein (Acr). We assessed SSS-induced benzo(a)pyrene diol epoxide (BPDE)- and cyclic propano-deoxyguanosine (PdG) adducts in bronchoalveolar lavage (BAL), lung, heart, liver, and bladder-mucosa from mice exposed to SSS for 16 weeks. In SSS exposed mice, Acr-dG adducts were the major type of PdG adducts formed in BAL (p < 0.001), lung (p < 0.05), and bladder mucosa (p < 0.001), with no significant accumulation of Acr-dG adducts in heart or liver. SSS exposure did not enhance BPDE-DNA adduct formation in any of these tissues. SSS exposure reduced nucleotide excision repair (p < 0.01) and base excision repair (p < 0.001) in lung tissue. The levels of DNA repair proteins, XPC and hOGG1, in lung tissues of exposed mice were significantly (p < 0.001 and p < 0.05) lower than the levels in lung tissues of control mice. We found that Acr can transform human bronchial epithelial and urothelial cells in vitro. We propose that induction of mutagenic Acr-DNA adducts, inhibition of DNA repair, and induction of cell transformation are three mechanisms by which SHS induces lung and bladder cancers.

The Association of Maternal Lifestyle with Birth Defects in Shaanxi Province, Northwest China

BACKGROUND

The main objective was to investigate the burden of birth defects among alive infants and explore the impact of maternal lifestyle during pregnancy on the burden of birth defects in Northwest China.

METHODS

A stratified multi-stage sampling method was used to study infants born during 2010-2013 (and their mothers) in Shaanxi province of Northwest China. Socio-demographic information was collected using a structured questionnaire, and medical records from the local hospitals were used to determine the final diagnosis of birth defects. Poisson regression analysis was performed to assess the association between maternal lifestyles during pregnancy and the burden of birth defects, while adjusting for potential confounders.

RESULTS

We sampled 29098 infants, of whom 629 (i.e. 216.17 per 10000) were observed to have congenital defects. Cardiovascular system defects (77.32 per 10000) were found to be the most common. Mothers who had ever consumed alcohol during pregnancy were found to have infants with a higher prevalence of some categories of birth defects, including nervous system (Prevalence Rate Ratio, PRR:14.67, 95% CI: 1.94, 110.92), cardiovascular system (PRR:3.22, 95% CI: 1.02, 10.16) and oral clefts (PRR:9.02, 95% CI: 2.08, 39.10) in contrast to infants of mothers without any alcohol consumption. Maternal passive smoking during pregnancy lead to the increased burden of malformations of eye, ear, face and neck (PRR:1.95, 95% CI: 1.15, 3.33), cardiovascular system (PRR:1.70, 95% CI: 1.25, 2.31) and respiratory system (PRR:9.94, 95% CI: 2.37, 41.76) in their newborns. Further, tea or coffee consumption during pregnancy was positively correlated with the burden of specific birth defects, such as cardiovascular system (PRR: 2.44, 95% CI: 1.33, 4.46) and genital organs (PRR:14.72, 95% CI: 1.87, 116.11) among infants.

CONCLUSIONS

The prevalence of birth defects was high in Shaanxi province of Northwest China. The unhealthy lifestyles of mothers during pregnancy may increase the prevalence of congenital malformations. These findings in future may have some important implications for prevention of birth defects in Northwest China.

Impact assessment of repeated exposure of organotypic 3D bronchial and nasal tissue culture models to whole cigarette smoke

Cigarette smoke (CS) has a major impact on lung biology and may result in the development of lung diseases such as chronic obstructive pulmonary disease or lung cancer. To understand the underlying mechanisms of disease development, it would be important to examine the impact of CS exposure directly on lung tissues. However, this approach is difficult to implement in epidemiological studies because lung tissue sampling is complex and invasive. Alternatively, tissue culture models can facilitate the assessment of exposure impacts on the lung tissue. Submerged 2D cell cultures, such as normal human bronchial epithelial (NHBE) cell cultures, have traditionally been used for this purpose. However, they cannot be exposed directly to smoke in a similar manner to the in vivo exposure situation. Recently developed 3D tissue culture models better reflect the in vivo situation because they can be cultured at the air-liquid interface (ALI). Their basal sides are immersed in the culture medium; whereas, their apical sides are exposed to air. Moreover, organotypic tissue cultures that contain different type of cells, better represent the physiology of the tissue in vivo. In this work, the utilization of an in vitro exposure system to expose human organotypic bronchial and nasal tissue models to mainstream CS is demonstrated. Ciliary beating frequency and the activity of cytochrome P450s (CYP) 1A1/1B1 were measured to assess functional impacts of CS on the tissues. Furthermore, to examine CS-induced alterations at the molecular level, gene expression profiles were generated from the tissues following exposure. A slight increase in CYP1A1/1B1 activity was observed in CS-exposed tissues compared with air-exposed tissues. A network-and transcriptomics-based systems biology approach was sufficiently robust to demonstrate CS-induced alterations of xenobiotic metabolism that were similar to those observed in the bronchial and nasal epithelial cells obtained from smokers.

CSEO - the Cigarette Smoke Exposure Ontology

BACKGROUND

In the past years, significant progress has been made to develop and use experimental settings for extensive data collection on tobacco smoke exposure and tobacco smoke exposure-associated diseases. Due to the growing number of such data, there is a need for domain-specific standard ontologies to facilitate the integration of tobacco exposure data.

RESULTS

The CSEO (version 1.0) is composed of 20091 concepts. The ontology in its current form is able to capture a wide range of cigarette smoke exposure concepts within the knowledge domain of exposure science with a reasonable sensitivity and specificity. Moreover, it showed a promising performance when used to answer domain expert questions. The CSEO complies with standard upper-level ontologies and is freely accessible to the scientific community through a dedicated wiki at https://publicwiki-01.fraunhofer.de/CSEO-Wiki/index.php/Main_Page.

CONCLUSIONS

The CSEO has potential to become a widely used standard within the academic and industrial community. Mainly because of the emerging need of systems toxicology to controlled vocabularies and also the lack of suitable ontologies for this domain, the CSEO prepares the ground for integrative systems-based research in the exposure science.

Maternal smoking during pregnancy and neural tube defects in offspring: a meta-analysis

PURPOSE

This study aims to examine the association between maternal smoking during pregnancy and neural tube defects (NTDs) in offspring.

METHODS

We retrieved published studies on the association between maternal smoking during pregnancy and NTDs risk in offspring. Meta-analysis was applied to calculate the overall odds ratios (ORs) and their 95 % confidence intervals (CIs). The publication bias was assessed by the Egger's regression asymmetry test and Begg's rank correlation test.

RESULTS

The overall effect of maternal smoking during pregnancy on NTDs was 1.03 (OR = 1.03, 95 % CI = 0.80-1.33). When subgroup analysis was conducted by geographic regions, the overall effects were 1.39 (OR = 1.39, 95 % CI = 1.18-1.64), 0.88 (OR = 0.88, 95 % CI = 0.66-1.17) in Europe and USA; when subgroup analysis was conducted by NTDs types, the overall effect was 1.55 (OR = 1.55, 95 % CI = 1.06-2.26) for spina bifida.

CONCLUSIONS

Women who smoked during pregnancy had mildly elevated risk of having infants with NTDs.

Effects of the administration of a catalase inhibitor into the fourth cerebral ventricle on cardiovascular responses in spontaneously hypertensive rats exposed to sidestream cigarette smoke

OBJECTIVE

Previous studies have demonstrated a relationship between brain oxidative stress and cardiovascular regulation. We evaluated the effects of central catalase inhibition on cardiovascular responses in spontaneously hypertensive rats exposed to sidestream cigarette smoke.

METHODS

Male Wistar Kyoto (WKY) rats and spontaneously hypertensive rats (SH) (16 weeks old) were implanted with a stainless steel guide cannula leading into the fourth cerebral ventricle (4th V). The femoral artery and vein were cannulated for arterial pressure and heart rate measurement and drug infusion, respectively. The rats were exposed to sidestream cigarette smoke for 180 minutes/day, 5 days/week for 3 weeks (CO: 100-300 ppm). The baroreflex was tested using a pressor dose of phenylephrine (8 μg/kg, bolus) and a depressor dose of sodium nitroprusside (50 μg/kg, bolus). Cardiovascular responses were evaluated before and 5, 15, 30 and 60 minutes after injection of a catalase inhibitor (3-amino-1,2,4-triazole, 0.001 g/100 μL) into the 4th V.

RESULTS

Vehicle administration into the 4th V did not affect the cardiovascular response, whereas administration of the central catalase inhibitor increased the basal HR and attenuated the bradycardic peak (p<0.05) to a greater extent in WKY rats exposed to sidestream cigarette smoke than in WKY rats exposed to fresh air. However, in spontaneously hypertensive rats, the effect of the catalase inhibitor treatment was stronger in the fresh air condition (p<0.05).

CONCLUSION

Administration of a catalase inhibitor into the 4th V combined with exposure to sidestream cigarette smoke has a stronger effect in WKY rats than in SH rats.

Comparison of electronic cigarette refill fluid cytotoxicity using embryonic and adult models

Electronic cigarettes (EC) and refill fluids are distributed with little information on their pre- and postnatal health effects. This study compares the cytotoxicity of EC refill fluids using embryonic and adult cells and examines the chemical characteristics of refill fluids using HPLC. Refill solutions were tested on human embryonic stem cells (hESC), mouse neural stem cells (mNSC), and human pulmonary fibroblasts (hPF) using the MTT assay, and NOAELs and IC(50)s were determined from dose-response curves. Spectral analysis was performed when products of the same flavor had different MTT outcomes. hESC and mNSC were generally more sensitive to refill solutions than hPF. All products from one company were cytotoxic to hESC and mNSC, but non-cytotoxic to hPF. Cytotoxicity was not due to nicotine, but was correlated with the number and concentration of chemicals used to flavor fluids. Additional studies are needed to fully assess the prenatal effect of refill fluids.

Sidestream cigarette smoke effects on cardiovascular responses in conscious rats: involvement of oxidative stress in the fourth cerebral ventricle

Background

Cigarette exposure increases brain oxidative stress. The literature showed that increased brain oxidative stress affects cardiovascular regulation. However, no previous study investigated the involvement of brain oxidative stress in animals exposed to cigarette and its relationship with cardiovascular regulation. We aimed to evaluate the effects of central catalase inhibition on baroreflex and cardiovascular responses in rats exposed to sidestream cigarette smoke (SSCS).

Methods

We evaluated males Wistar rats (320-370 g), which were implanted with a stainless steel guide cannula into the fourth cerebral ventricle (4th V). Femoral artery and vein were cannulated for mean arterial pressure (MAP) and heart rate (HR) measurement and drug infusion, respectively. Rats were exposed to SSCS during three weeks, 180 minutes, 5 days/week (CO: 100-300 ppm). Baroreflex was tested with a pressor dose of phenylephrine (PHE, 8 μg/kg, bolus) to induce bradycardic reflex and a depressor dose of sodium nitroprusside (SNP, 50 μg/kg, bolus) to induce tachycardic reflex. Cardiovascular responses were evaluated before, 5, 15, 30 and 60 minutes after 3-amino-1,2,4-triazole (ATZ, catalase inhibitor, 0.001 g/100 μL) injection into the 4th V.

Results

Central catalase inhibition increased basal HR in the control group during the first 5 minutes. SSCS exposure increased basal HR and attenuated bradycardic peak during the first 15 minutes.

Conclusion

We suggest that SSCS exposure affects cardiovascular regulation through its influence on catalase activity.

Maternal smoking in pregnancy and birth defects: a systematic review based on 173 687 malformed cases and 11.7 million controls

BACKGROUND

There is uncertainty over whether maternal smoking is associated with birth defects. We conducted the first ever comprehensive systematic review to establish which specific malformations are associated with smoking.

METHODS

Observational studies published 1959–2010 were identified (Medline), and included if they reported the odds ratio (OR) for having a non-chromosomal birth defect among women who smoked during pregnancy compared with non-smokers. ORs adjusted for potential confounders were extracted (e.g. maternal age and alcohol), otherwise unadjusted estimates were used. One hundred and seventy-two articles were used in the meta-analyses: a total of 173 687 malformed cases and 11 674 332 unaffected controls.

RESULTS

Significant positive associations with maternal smoking were found for: cardiovascular/heart defects [OR 1.09, 95% confidence interval (CI) 1.02–1.17]; musculoskeletal defects (OR 1.16, 95% CI 1.05–1.27); limb reduction defects (OR 1.26, 95% CI 1.15–1.39); missing/extra digits (OR 1.18, 95% CI 0.99–1.41); clubfoot (OR 1.28, 95% CI 1.10–1.47); craniosynostosis (OR 1.33, 95% CI 1.03–1.73); facial defects (OR 1.19, 95% CI 1.06–1.35); eye defects (OR 1.25, 95% CI 1.11–1.40); orofacial clefts (OR 1.28, 95% CI 1.20–1.36); gastrointestinal defects (OR 1.27, 95% CI 1.18–1.36); gastroschisis (OR 1.50, 95% CI 1.28–1.76); anal atresia (OR 1.20, 95% CI 1.06–1.36); hernia (OR 1.40, 95% CI 1.23–1.59); and undescended testes (OR 1.13, 95% CI 1.02–1.25). There was a reduced risk for hypospadias (OR 0.90, 95% CI 0.85–0.95) and skin defects (OR 0.82, 0.75–0.89). For all defects combined the OR was 1.01 (0.96–1.07), due to including defects with a reduced risk and those with no association (including chromosomal defects).

CONCLUSIONS

Birth defects that are positively associated with maternal smoking should now be included in public health educational materials to encourage more women to quit before or during pregnancy.

Comparison of the toxicity of smoke from conventional and harm reduction cigarettes using human embryonic stem cells

This study evaluated the hypothesis that smoke from harm reduction cigarettes impedes attachment and proliferation of H9 human embryonic stem cells (hESCs). Smoke from three harm reduction brands was compared with smoke from a conventional brand. Doses of smoke were measured in puff equivalents (PE) (1 PE = the amount of smoke in one puff that dissolves in 1 ml of medium). Cytotoxic doses were determined using morphological criteria and trypan blue staining, and apoptosis was confirmed using Magic Red staining. Attachment and proliferation of hESC were followed at a noncytotoxic dose in time-lapse videos collected using BioStation technology. Data were mined from videos either manually or using video bioinformatics subroutines developed with CL-Quant software. Mainstream (MS) and sidestream (SS) smoke from conventional and harm reduction cigarettes induced apoptosis in hESC colonies at 1 PE. At 0.1 PE (noncytotoxic), SS smoke from all brands inhibited attachment of hESC colonies to Matrigel with the strongest inhibition occurring in harm reduction brands. At 0.1 PE, SS smoke, but not MS smoke, from all brands inhibited hESC growth, and two harm reduction brands were more potent than the conventional brand. In general, hESC appeared more sensitive to smoke than their mouse ESC counterparts. Although harm reduction cigarettes are often marketed as safer than conventional brands, our assays show that SS smoke from harm reduction cigarettes was at least as potent or in some cases more potent than smoke from a conventional brand and that SS smoke was more inhibitory than MS smoke in all assays.

Role of transporter-mediated efflux in the placental biodisposition of bupropion and its metabolite, OH-bupropion

Cigarette smoking during pregnancy is a preventable risk factor associated with maternal and fetal complications. Bupropion is an antidepressant used successfully for smoking cessation in non-pregnant patients. Our goal is to determine whether it could benefit the pregnant patient seeking smoking cessation. The aim of this investigation was to determine the role of human placenta in the disposition of bupropion and its major hepatic metabolite, OH-bupropion. The expression of efflux transporters P-gp and BCRP was determined in placental brush border membrane (n=200) and revealed a positive correlation (p<0.05). Bupropion was transported by BCRP (K(t) 3 microM, V(max) 30 pmol/mg protein/min) and P-gp (K(t) 0.5 microM, V(max) 6 pmol/mg protein min) in placental inside-out vesicles (IOVs). OH-bupropion crossed the dually-perfused human placental lobule without undergoing further metabolism, nor was it an efflux substrate of P-gp or BCRP. In conclusion, our data indicate that human placenta actively regulates the disposition of bupropion (via metabolism, active transport), but not its major hepatic metabolite, OH-bupropion.

Familial factors confound the association between maternal smoking during pregnancy and young adult offspring overweight

BACKGROUND

Smoking during pregnancy has been shown to increase the risks of several adverse birth outcomes. Associations with overweight and/or obesity in the offspring have also been suggested. We aim to investigate whether familial factors confound the association between maternal smoking during pregnancy and overweight in early adulthood in young Swedish males born 1983-88.

METHODS

In a population-based Swedish cohort comprising 124 203 singleton males born to Nordic mothers between 1983 and 1988, we examined the association between maternal smoking during pregnancy and the risk of overweight in the offspring at age ∼18 years. We also investigated the association within siblings, controlling for common genes and shared environment.

RESULTS

In the cohort analyses, the risk of overweight was increased in sons of smoking mothers compared with sons of non-smokers: adjusted odds ratios 1.41, 95% confidence interval (CI) 1.34-1.49, and 1.56, 95% CI 1.46-1.66, for one to nine cigarettes per day, and >10 cigarettes per day, respectively. Stratifying for maternal smoking habits across two subsequent male pregnancies, there was an increased risk of overweight for the second son only if the mother was smoking in both male pregnancies. The effect of smoking during pregnancy on the offspring's body mass index was not present when the association was evaluated within full and half sibling pairs.

CONCLUSION

The association between maternal smoking during pregnancy and offspring's risk of overweight appears to be confounded by familial factors.

Comparison of toxicity of smoke from traditional and harm-reduction cigarettes using mouse embryonic stem cells as a novel model for preimplantation development

BACKGROUND

Embryonic stem cells (ESC), which originate from the inner cell mass of blastocysts, are valuable models for testing the effects of toxicants on preimplantation development. In this study, mouse ESC (mESC) were used to compare the toxicity of mainstream (MS) and sidestream (SS) cigarette smoke on cell attachment, survival and proliferation. In addition, smoke from a traditional commercial cigarette was compared with smoke from three harm-reduction brands.

METHODS

MS and SS smoke solutions were made using an analytical smoking machine and tested at three doses using D3 mESC plated on 0.2% gelatin. At 6 and 24 h, images were taken and the number of attached cells was evaluated.

RESULTS

Both MS and SS smoke from traditional and harm-reduction cigarettes inhibited cell attachment, survival and proliferation dose dependently. For all brands, SS smoke was more potent than MS smoke. However, removal of the cigarette filter increased the toxicity of MS smoke to that of SS smoke. Both MS and SS smoke from harm-reduction cigarettes were as inhibitory, or more inhibitory, than their counterparts from the traditional brand. When preimplantation mouse embryos were cultured for 1 h in MS or SS smoke solutions from a harm-reduction brand, blastomeres became apoptotic, in agreement with the data obtained using mESC.

CONCLUSIONS

mESC provide a valuable model for toxicological studies on the preimplantation stage of development and were used to show that MS and SS smoke from traditional and harm-reduction cigarettes are detrimental to embryonic cells prior to implantation.