Acrolein Exposure in U.S. Tobacco Smokers and Non-Tobacco Users: NHANES 2005-2006

Correlation of exposure to volatile organic compounds with myocardial infarction: A Cross-sectional study based on NHANES 2011-2018

Myocardial infarction (MI), commonly referred to as a heart attack, ranks among the foremost causes of death worldwide. The contribution of exposure to volatile organic compounds (VOCs) to MI is still not well established. This study aims to examine how urinary metabolites of 19 volatile organic compounds (mVOCs) correlate with MI risk in the ordinary population. The data were extracted from the National Health and Nutrition Examination Survey spanning from 2011 to 2018, a nationally representative program conducted by the Centers for Disease Control and Prevention (CDC) to collect and assess the health and nutritional status of the non-institutionalized U.S. population through interviews and physical examinations. The relationship between a single mVOC and MI was analyzed by applying a logistic regression model. The nonlinear relationship between a single mVOC and MI was investigated with the help of a restricted cubic spline regression model. The overall association between mVOCs and MI was examined using a weighted quantile sum (WQS) regression model. The analysis included 5,211 participants, among whom 209 experienced MI, with mVOC levels assessed. A positive association between N-acetyl-S-(3-hydroxypropyl)-L-cysteine (3HPMA) [OR, 1.95; 95% CI, (1.06, 3.58)] and MI incidence was observed after adjustment for potential confounders. Similarly, N-acetyl-S-(2-cyanoethyl)-L-cysteine (CYMA) was also significantly associated with MI incidence [OR, 1.8; 95% CI, (1.14, 2.83)]. Each incremental unit increase in WQS was linked to a 20.4% rise in MI risk (95% CI, 1.05, 1.38). Among them, N-acetyl-S-(3,4-dihydroxybutyl)-L-cysteine (DHBMA), N-acetyl-S-(2-carboxyethyl)-L-cysteine (CEMA), CYMA, N-acetyl-S-(phenyl-2-hydroxyethyl)-L-cysteine (PHEMA), 3HPMA, and 3- and 4-methylhippuric acid (3,4MHA) were identified as key contributors, with DHBMA showing the highest weight (0.27). mVOCs are metabolic derivatives of VOC exposure, with common sources including industrial emissions, environmental pollution, and tobacco combustion. The findings revealed a significant association between urinary mVOCs and MI, implying exposure to these compounds may be linked to an increased MI risk.

Adrenergic receptor subtypes differentially influence acrolein-induced ventilatory, vascular leakage, and inflammatory responses

Adrenergic receptors (AR) are manipulated therapeutically for the treatment of pulmonary and cardiovascular diseases; however, their role in air pollutant-induced respiratory effects is poorly understood. We examined the contribution of AR-subtypes in acrolein-induced respiratory effects through selective receptor inhibition. We pre-treated 12-week-old male Wistar-Kyoto rats intraperitoneally daily for 9-days with subtype-specific AR antagonists prazosin (PRZ, α1-AR antagonist; 2-mg/kg-day), yohimbine (YOH, α2-AR antagonist; 5-mg/kg-day), or propranolol (PROP, β-AR antagonist; 10-mg/kg-day). On day-8 and day-9 of treatment, rats were exposed nose-only to air or acrolein (1.6 or 3.2 ppm), ∼4 h/day. Head-out plethysmography during exposure on Day-9 revealed overall concentration-dependent acrolein-related reduced ventilatory capacity, which was exacerbated in PRZ- and YOH-treated animals. Nasal (NALF) and bronchoalveolar lavage fluid (BALF), and blood samples were collected on day-9. Plasma epinephrine levels did not change; however, corticosterone decreased in YOH- and PROP-treated air-exposed animals. Adrenal and spleen weights were higher in PRZ-treated animals. Acrolein, 3.2-ppm depleted circulating lymphocytes in saline-treated and increased neutrophils in PRZ- and YOH-treated animals. NALF and BALF analysis indicated 3.2-ppm acrolein-induced neutrophilic and lymphocytic inflammation (NALF>BALF), which was exacerbated in lung of PRZ- and YOH-treated rats and slightly dampened in PROP-treated rats. However, acrolein-induced vascular protein leakage and increases in inflammatory cytokines in NALF were reduced by PROP-treatment. In conclusion, this study highlights sympathetically-mediated adrenoreceptor influence on acrolein-indued respiratory health effects, and AR subtype-specific modulation of breathing, hemodynamic, and inflammatory responses. These results have broader translational implications, as those receiving adrenergic agonistic/antagonistic therapies might experience variable air pollution-related respiratory health effects.

Assessing the impact of volatile organic compounds on cardiovascular health: Insights from the National Health and Nutrition Examination Survey 2011-2020

Volatile organic compounds (VOCs) are environmental pollutants that may negatively impact cardiovascular health. This study investigates the association between VOC mixtures, measured through urinary VOC metabolites (VOCMs), and cardiovascular health using Life's Essential 8 (LE8) scores. Data from the National Health and Nutrition Examination Survey (NHANES) 2011-2020 were analyzed for 2967 adults aged 20-79 years. Multiple statistical methods, including correlation analysis, variance inflation factor (VIF) analysis, quantile g-computation (q-gcomp), and Bayesian kernel machine regression (BKMR), were applied to assess the association between VOCMs and LE8 scores. Sensitivity analyses were conducted with different random seeds and subsampling techniques to confirm robustness. Correlation and VIF analyses revealed strong collinearity among VOCMs, highlighting the need for advanced models. Survey-weighted regression indicated that lower VOC exposure was associated with better cardiovascular health. Q-gcomp identified both positive and negative associations between individual VOCMs and LE8 scores, with some unexpected positive associations. BKMR highlighted the complex mixture effects of VOCMs on cardiovascular health. Sensitivity analyses confirmed the consistency of these findings. This study underscores the intricate relationship between VOC exposure and cardiovascular health and the necessity of advanced statistical methods for mixture analysis. Despite some unexpected findings, the results suggest that VOC exposure, as reflected by urinary VOCMs, is associated with adverse cardiovascular health outcomes. Further research is needed to clarify the biological mechanisms and implications of these associations.

Acrolein exposure associated with kidney damage: a cross‑sectional study

Acrolein (Acr) is a common volatile toxic substance excreted by the kidneys. There are no studies that specifically look at the effects of Acr on kidney function. This study was designed to investigate the relationship between Acr and kidney damage. A cross-sectional study of data (n = 4951) from the 2011-2018 National Health and Nutrition Examination Survey (NHANES) was conducted. Participants' urinary Acr concentration, estimated glomerular filtration rate (eGFR), and urinary albumin to creatinine ratio (UACR) were recorded based on laboratory tests. The number of participants with chronic kidney disease (CKD) was counted. Urinary Acr concentration was divided into quartiles. The association of urinary Acr with CKD and eGFR was investigated using multivariate linear regression, multivariate logistic regression, and smooth curve fitting. Subgroup analyses, interaction tests and sensitivity analyses were used to examine the independence of the Acr-CKD and Acr-eGFR associations in the population. In 4951 participants, urinary Acr concentration was positively associated with CKD risk and negatively associated with eGFR. In the fully adjusted model, each log2Acr increase of one unit was associated with a 6% increased risk of CKD (OR = 1.06, 95% CI 1.01, 1.13) and a 0.54 mL/min/1.73 m2 decrease in eGFR (β = - 0.54, 95% CI - 0.95, - 0.13). For categorical log2Acr, for each log2Acr increase of one unit, the risk of CKD was 29% higher in the Q4 group than in the Q1 group (OR = 1.29, 95% CI 1.01, 1.64), while eGFR was 1.9 mL/min/1.73 m2 lower in the Q4 group than in the Q1 group (β = - 1.90, 95% CI - 3.65, - 0.14). Smooth curve fitting confirmed urinary Acr's nonlinear positive and negative correlations with CKD and eGFR. According to subgroup analyses, sensitivity analyses and interaction tests, the confounding variables did not affect the independent correlations of urinary Acr with CKD and eGFR. Our study found that Acr exposure was significantly associated with kidney damage. Our study provides a new piece of research evidence to support a link between the volatile toxic substance Acr and a decline in kidney function.

Biomarkers of Exposure to Nicotine and Selected Toxicants in Individuals Who Use Alternative Tobacco Products Sold in Japan and Canada from 2018 to 2019

BACKGROUND

Comparisons of nicotine and toxicant exposures between people who use different alternative tobacco products remain underexplored.

METHODS

This cross-sectional, multicountry study analyzed urinary metabolites of nicotine, tobacco-specific nitrosamines [4-methylnitrosamino-1-3-pyridyl-1-butanone (NNK)], and volatile organic compounds (acrolein, acrylamide, and acrylonitrile) among established users (n = 550) in Japan and Canada. Participants exclusively or concurrently used nicotine vaping products (NVP; Canada only), heated tobacco products (HTP; Japan only), and combustible cigarettes (CC; Japan and Canada) or abstained (Japan and Canada).

RESULTS

All product groups showed substantial nicotine exposure. Both HTPs and NVPs exposed exclusive users to lower toxicant levels than exclusive CC use. Canadian participants who exclusively used NVPs exhibited lower NNK and acrolein exposure but higher acrylamide exposure than Japanese participants who exclusively used HTPs. Concurrent use of CCs alongside alternative products exposed users to higher toxicant levels compared with exclusive use of either alternative product.

CONCLUSIONS

Exclusive use of alternative tobacco products results in significant nicotine exposure but substantially lower toxicant exposure compared with exclusive CC use. People who use HTPs in Japan may experience higher exposure to nicotine and certain toxicants (NNK and acrolein) than people who use NVPs in Canada. Concurrent use results suggest that partially substituting CCs with alternative products may reduce toxicant exposure but to a lesser extent than completely transitioning to alternative products.

IMPACT

Exposure patterns between two popular alternative tobacco products differ. The overall toxicant exposure from these products is lower than from CCs, providing critical data for regulatory decisions and public health considerations.

Acrolein exposure affects ovarian function by interfering with glycolysis and mitochondrial energy metabolism in mouse

Acrolein is a widespread contaminant found in both diet and environment, entering the human body through food, alcohol, smoking, and exposure to fuel combustion fumes. While prior studies have highlighted acrolein's harmful impact on oocyte quality and early embryonic development in vitro, the specific mechanisms by which acrolein affects the female reproductive system in vivo remain poorly understood. This study first confirmed that in vitro acrolein exposure disrupts spindle morphology and chromosome alignment during the mid-MI stage of oocyte development, thus hindering oocyte maturation. Besides, exposure to acrolein not only stunts growth in mice but also impairs ovarian development, decreases the ovarian coefficient, disrupts follicular development, and increases the count of atretic follicles in vivo. Additional research has shown that acrolein exposure reduces the activity of key enzymes in glycolysis, pyruvate metabolism, and the tricarboxylic acid cycle within the ovaries. It also suppresses mitochondrial complex expression and disturbs the balance between mitochondrial fission and fusion, as confirmed by metabolomic analyses. Moreover, acrolein exposure in vivo induced granulosa cell apoptosis and reduced oocyte number. In summary, acrolein exposure impairs glucose metabolism and induces mitochondrial dysfunction in the ovaries.

Serum albumin and liver dysfunction mediate the associations between organophosphorus pesticide exposure and hypertension among US adults

BACKGROUND

Human health is commonly threatened by organophosphorus pesticides (OPPs) due to their widespread use and biological characteristics. However, the combined effect of mixtures of OPPs metabolites on the risk of hypertension and potential mechanism remain limited.

OBJECTIVES

To comprehensively investigate the effects between OPPs exposure on hypertension risk and explore and underlying mechanism among US general population.

METHODS

This cross-sectional study collected US adults who had available data on urine OPPs metabolites (dialkyl phosphate compounds, DAPs) from the National Health and Nutrition Examination Survey (NHANES) to assess the relationships of DAPs with hypertension risk. Survey-weighted logistic regression, restricted cubic spline (RCS), and mixed exposure analysis models [weighted quantile sum regression (WQS) and Bayesian kernel machine regression (BKMR)] were used to analyze individual, dose-response and combined associations between urinary DAPs metabolites and hypertension risk, respectively. Mediation analysis determined the potential intermediary role of serum albumin and liver function in the above associations.

RESULTS

Compared with the reference group, participants with the highest tertile levels of DEP, DMTP, DETP, and DMDTP experienced increased risk of hypertension by 1.21-fold (95%CI: 1.02-1.36), 1.20-fold (95%CI: 1.02-1.42), 1.19-fold (95%CI: 1.01-1.40), and 1.17-fold (95%CI: 1.03-1.43), respectively. RCS curve also showed positive exposure-response associations of individual DAPs with hypertension risk. WQS and BKMR analysis further confirmed DAP mixtures were significantly associated with increased risk of hypertension, with DEP identified as a major contributor to the combined effect. Mediation analysis indicated that serum albumin and AST/ALT ratios played crucial mediating roles in the relationships between individual and mixed urinary DAPs and the prevalence of hypertension.

CONCLUSION

Our findings provided more comprehensive and novel perspectives into the individual and combined effects of urinary OPPs matabolites on the increased risk of hypertension and the possible driving mechanism, which would be of great significance for environmental control and early prevention of hypertension.

Effect of allyl isothiocyanate on 4-HNE induced glucocorticoid resistance in COPD and the underlying mechanism

Chronic obstructive pulmonary disease (COPD) is a progressive inflammatory condition, and its clinical management primarily targets bronchodilation and anti-inflammatory therapy. However, these treatments often fail to directly address the progression of COPD, particularly its associated glucocorticoid (GC) resistance. This study elucidates the mechanisms underlying GC resistance in COPD and explores the therapeutic potential of allyl isothiocyanate (AITC) in modulating MRP1 transport. We assessed the levels of the oxidative stress product 4-HNE, HDAC2 protein, inflammatory markers, and pulmonary function indices using animal and cell models of GC-resistant COPD. The cascade effects of these factors were investigated through interventions involving AITC, protein inhibitors, and dexamethasone (DEX). Cigarette smoke-induced oxidative stress in COPD leads to the accumulation of the lipid peroxidation product 4-HNE, which impairs HDAC2 protein activity and diminishes GC-mediated anti-inflammatory sensitivity due to disrupted histone deacetylation. AITC regulates MRP1, facilitating the effective efflux of 4-HNE from cells, thereby reducing HDAC2 protein degradation and restoring dexamethasone sensitivity in COPD. These findings elucidate the mechanism of smoking-induced GC resistance in COPD and highlight MRP1 as a potential therapeutic target, as well as the enormous potential of AITC for combined GC therapy in COPD, promoting their clinical applications.

Association of volatile organic compound exposure with metabolic syndrome and its components: a nationwide cross-sectional study

BACKGROUND

Metabolic syndrome (MetS) is a health issue consisting of multiple metabolic abnormalities. The impact of exposure to volatile organic compounds (VOCs) on MetS and its components remains uncertain. This study aimed to assess the associations of individual urinary metabolites of VOC (mVOCs) and mVOC mixtures with MetS and its components among the general adult population in the United States.

METHODS

A total of 5345 participants with eligible data were filtered from the 2011-2020 cycles of the National Health and Nutrition Examination Survey. Multivariate logistic regression models were applied to assess the associations of individual mVOCs with MetS and its components. The least absolute shrinkage and selection operator (LASSO) regression models were constructed to identify more relevant mVOCs. The weight quantile sum regression model was applied to further explore the links between mVOC co-exposure and MetS and its components.

RESULTS

The results indicated positive associations between multiple mVOCs and MetS, including CEMA, DHBMA, and HMPMA. CEMA was found to be positively correlated with all components of MetS. HMPMA was associated with elevated triglyceride (TG), reduced high-density lipoprotein, and fasting blood glucose (FBG) impairment; 3HPMA was associated with an elevated risk of high TG and FBG impairment; and DHBMA had positive associations with elevated TG and high blood pressure. The co-exposure of LASSO-selected mVOCs was associated with an increased risk of elevated TG, high blood pressure, and FBG impairment.

CONCLUSION

Positive associations of certain individual urinary mVOCs and mVOC mixtures with MetS and its components were observed by utilizing multiple statistical models and large-scale national data. These findings may serve as the theoretical basis for future experimental and mechanistic studies and have important implications for public health.

Methyl vinyl ketone and its analogs covalently modify PI3K and alter physiological functions by inhibiting PI3K signaling

Reactive carbonyl species (RCS), which are abundant in the environment and are produced in vivo under stress, covalently bind to nucleophilic residues such as Cys in proteins. Disruption of protein function by RCS exposure is predicted to play a role in the development of various diseases such as cancer and metabolic disorders, but most studies on RCS have been limited to simple cytotoxicity validation, leaving their target proteins and resulting physiological changes unknown. In this study, we focused on methyl vinyl ketone (MVK), which is one of the main RCS found in cigarette smoke and exhaust gas. We found that MVK suppressed PI3K-Akt signaling, which regulates processes involved in cellular homeostasis, including cell proliferation, autophagy, and glucose metabolism. Interestingly, MVK inhibits the interaction between the epidermal growth factor receptor and PI3K. Cys656 in the SH2 domain of the PI3K p85 subunit, which is the covalently binding site of MVK, is important for this interaction. Suppression of PI3K-Akt signaling by MVK reversed epidermal growth factor-induced negative regulation of autophagy and attenuated glucose uptake. Furthermore, we analyzed the effects of the 23 RCS compounds with structures similar to MVK and showed that their analogs also suppressed PI3K-Akt signaling in a manner that correlated with their similarities to MVK. Our study demonstrates the mechanism of MVK and its analogs in suppressing PI3K-Akt signaling and modulating physiological functions, providing a model for future studies analyzing environmental reactive species.

Supersulfide prevents cigarette smoke extract-induced mitochondria hyperfission and cardiomyocyte early senescence by inhibiting Drp1-filamin complex formation

Smoking is one of the most serious risk factors for cardiovascular diseases. Although cigarette mainstream and sidestream smoke are significant contributors to increased cardiovascular mortality and morbidity, the underlying mechanism is still unclear. Here, we report that exposure of rat neonatal cardiomyocytes to cigarette smoke extract (CSE) induces mitochondrial hyperfission-mediated myocardial senescence. CSE leads to mitochondrial fission and reactive oxygen species (ROS) production through the complex formation between mitochondrial fission factor Drp1 and actin-binding protein, filamin A. Pharmacological perturbation of interaction between Drp1 and filamin A by cilnidipine and gene knockdown of Drp1 or filamin A inhibited CSE-induced mitochondrial hyperfission and ROS production as well as myocardial senescence. We previously reported that Drp1 activity is controlled by supersulfide-induced Cys644 polysulfidation. The redox-sensitive Cys644 was critical for CSE-mediated interaction with filamin A. The administration of supersulfide donor, Na2S3 also improved mitochondrial hyperfission-mediated myocardial senescence induced by CSE. Our results suggest the important role of Drp1-filamin A complex formation on cigarette smoke-mediated cardiac risk and the contribution of supersulfide to mitochondrial fission-associated myocardial senescence.

Influence of Half-life and Smoking/Nonsmoking Ratio on Biomarker Consistency between Waves 1 and 2 of the Population Assessment of Tobacco and Health Study

BACKGROUND

Biomarkers of exposure are tools for understanding the impact of tobacco use on health outcomes if confounders like demographics, use behavior, biological half-life, and other sources of exposure are accounted for in the analysis.

METHODS

We performed multiple regression analysis of longitudinal measures of urinary biomarkers of alkaloids, tobacco-specific nitrosamines, polycyclic aromatic hydrocarbons, volatile organic compounds (VOC), and metals to examine the sample-to-sample consistency in Waves 1 and 2 of the Population Assessment of Tobacco and Health (PATH) Study including demographic characteristics and use behavior variables of persons who smoked exclusively. Regression coefficients, within- and between-person variance, and intra-class correlation coefficients (ICC) were compared with biomarker smoking/nonsmoking population mean ratios and biological half-lives.

RESULTS

Most biomarkers were similarly associated with sex, age, race/ethnicity, and product use behavior. The biomarkers with larger smoking/nonsmoking population mean ratios had greater regression coefficients related to recency of exposure. For VOC and alkaloid metabolites, longer biological half-life was associated with lower within-person variance. For each chemical class studied, there were biomarkers that demonstrated good ICCs.

CONCLUSIONS

For most of the biomarkers of exposure reported in the PATH Study, for people who smoke cigarettes exclusively, associations are similar between urinary biomarkers of exposure and demographic and use behavior covariates. Biomarkers of exposure within-subject consistency is likely associated with nontobacco sources of exposure and biological half-life.

IMPACT

Biomarkers measured in the PATH Study provide consistent sample-to-sample measures from which to investigate the association of adverse health outcomes with the characteristics of cigarettes and their use.

Serum metabolome and liver transcriptome reveal acrolein inhalation-induced sex-specific homeostatic dysfunction

Acrolein, a respiratory irritant, induces systemic neuroendocrine stress. However, peripheral metabolic effects have not been examined. Male and female WKY rats were exposed to air (0 ppm) or acrolein (3.16 ppm) for 4 h, followed by immediate serum and liver tissue collection. Serum metabolomics in both sexes and liver transcriptomics in males were evaluated to characterize the systemic metabolic response. Of 887 identified metabolites, > 400 differed between sexes at baseline. An acrolein biomarker, 3-hydroxypropyl mercapturic acid, increased 18-fold in males and 33-fold in females, indicating greater metabolic detoxification in females than males. Acrolein exposure changed 174 metabolites in males but only 50 in females. Metabolic process assessment identified higher circulating free-fatty acids, glycerols, and other lipids in male but not female rats exposed to acrolein. In males, acrolein also increased branched-chain amino acids, which was linked with metabolites of nitrogen imbalance within the gut microbiome. The contribution of neuroendocrine stress was evident by increased corticosterone in males but not females. Male liver transcriptomics revealed acrolein-induced over-representation of lipid and protein metabolic processes, and pathway alterations including Sirtuin, insulin-receptor, acute-phase, and glucocorticoid signaling. In sum, acute acrolein inhalation resulted in sex-specific serum metabolomic and liver transcriptomic derangement, which may have connections to chronic metabolic-related diseases.

The association between exposure to volatile organic compounds and serum lipids in the US adult population

BACKGROUND AND AIM

Epidemiological evidence on the relationship between exposure to volatile organic compounds (VOCs), both single and mixed, and serum lipid levels is limited, and their relationship remains unclear. Our study aimed to investigate the associations of exposure to VOCs with serum lipid levels in the US adult population.

METHODS AND RESULTS

The study examined the association of 16 VOC levels (2-methylhippuric acid, 3- and 4-methylhippuric acid, N-acetyl-S-(2-carbamoylethyl)-L-cysteine, N-acetyl-S-(N-methylcarbamoyl)-L-cysteine, 2-aminothiazoline-4-carboxylic acid, N-acetyl-S-(benzyl)-L-cysteine, N-acetyl-S-(n-propyl)-L-cysteine, N-acetyl-S-(2-carboxyethyl)-L-cysteine, N-acetyl-S-(2-cyanoethyl)-L-cysteine, N-acetyl-S-(3,4-dihydroxybutyl)-L-cysteine, N-acetyl-S-(2-hydroxypropyl)-L-cysteine. N-Acetyl-S-(3-hydroxypropyl)-L-cysteine, mandelic acid, N-acetyl-S-(4-hydroxy-2-butenyl)-L-cysteine, phenylglyoxylic acid and N-acetyl-S-(3-hydroxypropyl-1-methyl)-L-cysteine) with total cholesterol (TC), triglyceride (TG), low-density lipoprotein cholesterol (LDL) and high-density lipoprotein cholesterol (HDL) using data from the National Health and Nutrition Examination Survey (NHANES) between 2011 and 2015, and a total of 1410 adults were enrolled. The association was evaluated by Bayesian kernel machine regression (BKMR), multiple linear regression and weighted quantile sum (WQS) regression. In BKMR analysis, exposure to VOCs is positively correlated with levels of TC, TG, and LDL-C. However, statistical significance was observed only for the impact on TG. Our linear regression analysis and WQS regression generally support the BKMR results. Several VOCs were positively associated with serum lipid profiles (e.g., the ln-transformed level of mandelic acid (MA) displayed an increase in estimated changes of 7.01 (95% CIs: 2.78, 11.24) mg/dL for TC level), even after the effective number of tests for multiple testing (P < 0.05).

CONCLUSIONS

Exposure to VOCs was associated with serum lipids, and more studies are needed to confirm these findings.

Sex-specific respiratory and systemic endocrine effects of acute acrolein and trichloroethylene inhalation

Acrolein and trichloroethylene (TCE) are priority hazardous air pollutants due to environmental prevalence and adverse health effects; however, neuroendocrine stress-related systemic effects are not characterized. Comparing acrolein, an airway irritant, and TCE with low irritancy, we hypothesized that airway injury would be linked to neuroendocrine-mediated systemic alterations. Male and female Wistar-Kyoto rats were exposed nose-only to air, acrolein or TCE in incremental concentrations over 30 min, followed by 3.5-hr exposure to the highest concentration (acrolein - 0.0, 0.1, 0.316, 1, 3.16 ppm; TCE - 0.0, 3.16, 10, 31.6, 100 ppm). Real-time head-out plethysmography revealed acrolein decreased minute volume and increased inspiratory-time (males>females), while TCE reduced tidal-volume. Acrolein, but not TCE, inhalation increased nasal-lavage-fluid protein, lactate-dehydrogenase activity, and inflammatory cell influx (males>females). Neither acrolein nor TCE increased bronchoalveolar-lavage-fluid injury markers, although macrophages and neutrophils increased in acrolein-exposed males and females. Systemic neuroendocrine stress response assessment indicated acrolein, but not TCE, increased circulating adrenocorticotrophic hormone, and consequently corticosterone, and caused lymphopenia, but only in males. Acrolein also reduced circulating thyroid-stimulating hormone, prolactin, and testosterone in males. In conclusion, acute acrolein inhalation resulted in sex-specific upper respiratory irritation/inflammation and systemic neuroendocrine alterations linked to hypothalamic-pituitary-adrenal axes activation, which is critical in mediating extra-respiratory effects.

Acrolein Exposure Impaired Glucose Homeostasis and Increased Risk of Type 2 Diabetes: An Urban Adult Population-Based Cohort Study with Repeated Measures

Acrolein is an identified high-priority hazardous air pollutant ubiquitous in daily life and associated with cardiometabolic risk that attracts worldwide attention. However, the etiology role of acrolein exposure in glucose dyshomeostasis and type 2 diabetes (T2D) is unclear. This repeated-measurement prospective cohort study included 3522 urban adults. Urine/blood samples were repeatedly collected for determinations of acrolein metabolites (N-acetyl-S-(3-hydroxypropyl)-l-cysteine, N-acetyl-S-(2-carboxyethyl)-l-cysteine; acrolein exposure biomarkers), glucose homeostasis, and T2D at baseline and a three-year follow-up. We found that each 3-fold increment in acrolein metabolites was cross-sectionally associated with 5.91-6.52% decrement in homeostasis model assessment-insulin sensitivity (HOMA-IS) and 0.07-0.14 mmol/L, 4.02-4.57, 5.91-6.52, 19-20, 18-19, and 23-31% increments in fasting glucose (FPG), fasting insulin (FPI), HOMA-insulin resistance (HOMA-IR), risks of prevalent IR, impaired fasting glucose (IFG), and T2D, respectively; longitudinally, participants with sustained-high acrolein metabolite levels had increased risks of incident IR, IFG, and T2D by 63-80, 87-99, and 120-154%, respectively (P < 0.05). In addition, biomarkers of heme oxygenase-1 activity (exhaled carbon monoxide), lipid peroxidation (8-iso-prostaglandin-F2α), protein carbonylation (protein carbonyls), and oxidative DNA damage (8-hydroxy-deoxyguanosine) mediated 5.00-38.96% of these associations. Our study revealed that acrolein exposure may impair glucose homeostasis and increase T2D risk via mediating mechanisms of heme oxygenase-1 activation, lipid peroxidation, protein carbonylation, and oxidative DNA damage.

Extracellular vesicles and COPD: foe or friend?

Chronic obstructive pulmonary disease (COPD) is a chronic inflammatory airway disease characterized by progressive airflow limitation. The complex biological processes of COPD include protein hydrolysis tissue remodeling, innate immune inflammation, disturbed host-pathogen response, abnormal cellular phenotype conversion, and cellular senescence. Extracellular vesicles (EVs) (including apoptotic vesicles, microvesicles and exosomes), are released by almost all cell types and can be found in a variety of body fluids including blood, sputum and urine. EVs are key mediators in cell-cell communication and can be used by using their bioactive substances (DNA, RNA, miRNA, proteins and other metabolites) to enable cells in adjacent and distant tissues to perform a wide variety of functions, which in turn affect the physiological and pathological functions of the body. Thus, EVs is expected to play an important role in the pathogenesis of COPD, which in turn affects its acute exacerbations and may serve as a diagnostic marker for it. Furthermore, recent therapeutic approaches and advances have introduced EVs into the treatment of COPD, such as the modification of EVs into novel drug delivery vehicles. Here, we discuss the role of EVs from cells of different origins in the pathogenesis of COPD and explore their possible use as biomarkers in diagnosis, and finally describe their role in therapy and future prospects for their application. Graphical Abstract.

Hydrogen sulfide protects Sertoli cells against toxicant Acrolein-induced cell injury

Acrolein (ACR), a highly toxic α,β-unsaturated aldehyde, is considered to be a common mediator behind the reproductive injury induced by various factors. However, the understanding of its reproductive toxicity and prevention in reproductive system is limited. Given that Sertoli cells provide the first-line defense against various toxicants and that dysfunction of Sertoli cell causes impaired spermatogenesis, we, therefore, examined ACR cytotoxicity in Sertoli cells and tested whether hydrogen sulfide (H₂S), a gaseous mediator with potent antioxidative actions, could have a protective effect. Exposure of Sertoli cells to ACR led to cell injury, as indicated by reactive oxygen species (ROS) generation, protein oxidation, P38 activation and ultimately cell death that was prevented by antioxidant N-acetylcysteine (NAC). Further studies revealed that ACR cytotoxicity on Sertoli cells was significantly exacerbated by the inhibition of H₂S-synthesizing enzyme cystathionine γ-lyase (CSE), while significantly suppressed by H₂S donor Sodium hydrosulfide (NaHS). It was also attenuated by Tanshinone IIA (Tan IIA), an active ingredient of Danshen that stimulated H₂S production in Sertoli cells. Apart from Sertoli cells, H₂S also protected the cultured germ cells from ACR-initiated cell death. Collectively, our study characterized H₂S as endogenous defensive mechanism against ACR in Sertoli cells and germ cells. This property of H₂S could be used to prevent and treat ACR-related reproductive injury.

Association of Urinary Biomarkers of Smoking-Related Toxicants with Lung Cancer Incidence in Smokers: The Multiethnic Cohort Study

BACKGROUND

While cigarette smoking is the leading cause of lung cancer, the majority of smokers do not develop the disease over their lifetime. The inter-individual differences in risk among smokers may in part be due to variations in exposure to smoking-related toxicants.

METHODS

Using data from a subcohort of 2,309 current smokers at the time of urine collection from the Multiethnic Cohort Study, we prospectively evaluated the association of ten urinary biomarkers of smoking-related toxicants [total nicotine equivalents (TNE), a ratio of total trans-3'-hydroxycotinine (3-HCOT)/cotinine (a phenotypic measure of CYP2A6 enzymatic activity), 4-(methylnitrosamino)-1-3-(pyridyl)-1-butanol (NNAL), S-phenylmercapturic acid (SPMA), 3-hydroxypropyl mercapturic acid (3-HPMA), phenanthrene tetraol (PheT), 3-hydroxyphenanthrene (PheOH), the ratio of PheT/PheOH, cadmium (Cd), and (Z)-7-(1R,2R,3R,5S)-3,5-dihydroxy-2-[(E,3S)-3-hydroxyoct-1-enyl]cyclopenyl]hept-5-enoic acid (8-iso-PGF2α)] with lung cancer risk (n = 140 incident lung cancer cases over an average of 13.4 years of follow-up). Lung cancer risk was estimated using Cox proportional hazards models.

RESULTS

After adjusting for decade of birth, sex, race/ethnicity, body mass index, self-reported pack-years, creatinine, and urinary TNE (a biomarker of internal smoking dose), a one SD increase in log total 3-HCOT/cotinine (HR, 1.33; 95% CI, 1.06-1.66), 3-HPMA (HR, 1.41; 95% CI, 1.07-1.85), and Cd (HR, 1.45; 95% CI, 1.18-1.79) were each associated with increased lung cancer risk.

CONCLUSIONS

Our study demonstrates that urinary total 3-HCOT/cotinine, 3-HPMA, and Cd are positively associated with lung cancer risk. These findings warrant replication and consideration as potential biomarkers for smoking-related lung cancer risk.

IMPACT

These biomarkers may provide additional information on lung cancer risk that is not captured by self-reported smoking history or TNE. See related commentary by Etemadi et al., p. 289.

Exposures to volatile organic compounds, serum vitamin D, and kidney function: association and interaction assessment in the US adult population

The relationships of exposures to volatile organic compounds (VOCs) with vitamin D and kidney function remain unclear. Our analyses included 6070 adults from 2003 to 2010 survey cycles of the National Health and Nutrition Examination Survey to explore associations of six VOCs with serum vitamin D, albumin-to-creatinine ratio (ACR), and estimated glomerular filtration rate (eGFR). The results suggested that dibromochloromethane was positively associated with ACR, and chloroform was inversely associated with ACR. U-shaped associations of toluene, m-/p-xylene, bromodichloromethane, and 1,4-dichlorobenzene with ACR were observed. Toluene, m-/p-xylene, and 1,4-dichlorobenzene were associated with eGFR in U-shaped manners, while bromodichloromethane and chloroform were inversely associated with eGFR. Elevation in 1,4-dichlorobenzene was associated with decrease in vitamin D, while chloroform and m-/p-xylene were in U-shaped associations with vitamin D. VOCs mixture was U-shaped associated with ACR, inversely associated with eGFR, and inversely associated with vitamin D. Vitamin D was in a U-shaped association with ACR. Vitamin D significantly interacted with VOCs on the two kidney parameters. In the US adult population, exposures to VOCs were associated with kidney function and serum vitamin D level decline, and the serum vitamin D may have interaction effects with VOCs exposures on kidney function.

Phthalate metabolite concentrations and effects on albuminuria in the US population

BACKGROUND

The usage pattern of phthalates has changed with the introduction of new alternatives such as 1,2-cyclohexane dicarboxylic acid, diisononyl ester (DINCH) and di-isodecyl phthalate (DiDP). However, the concentrations of these alternatives at the population level and their effects on endothelial function are under-studied.

OBJECTIVES

We examined the concentrations of the new alternatives and their previous counterparts, as well as the associations between phthalate exposure and albuminuria in the general US population.

METHODS

In total, 2672 participants from the National Health and Nutrition Examination Survey (NHANES) 2017-2018 were enrolled in this study, and we obtained data on 19 urinary phthalate metabolites, albumin, and creatinine. The distributions of urinary phthalates were studied by age and sex. Linear and logistic regressions were used to estimate the association between urinary phthalate metabolites and albumin.

RESULTS

The geometric mean of the total phthalate concentrations in males and females was 124.97 and 113.09 ng/mL respectively. The detection rates of most urinary phthalate metabolites were greater than 95 %. The major phthalate metabolites found in the US population were MEP (24.20 %) and MECPTP (23.76 %). More positive relationships between phthalate and micro- plus albuminuria were found in females aged ≥ 60 years group（1.49 (95 % CI: 1.08-1.90), 1.44 (95 % CI: 1.06-1.81), 1.52 (95 % CI: 1.14-1.90), 1.41(95 % CI: 1.04-1.78), 1.29(95 % CI: 1.01-1.58), 1.60(95 % CI: 1.20-2.01), 1.45(95 % CI:1.14-1.77), and 1.55(95 % CI: 1.22-1.87) in MECPP, MEHHP, MEOHP, MEHP, MCPP, MHBP, MHNCH and MCOCH respectively）. In total population, logistic regression showed that all traditional phthalate metabolites were associated with an increased proportion of albuminuria (OR range from 1.19 to 1.40, all p < 0.05). However, three new alternatives were not associated with albuminuria (OR range from 1.01 to 1.05, all p > 0.05), and six new alternatives were associated with an increased proportion of albuminuria (OR range from 1.14 to 1.30, all p < 0.05).

CONCLUSIONS

Children have higher metabolite concentrations than adults. Exposure to certain phthalates may disrupt albuminuria homeostasis, especially in older females. Alternative phthalates may have a lower impact on albuminuria than conventional phthalates. The safety of the new alternatives should be interpreted with caution, as more research is still required.

Towards a novel application of wastewater-based epidemiology in population-wide assessment of exposure to volatile organic compounds

In this study, we investigated the feasibility of detecting 35 urinary biomarkers of volatile organic compounds (VOCs) exposure in community wastewater. 24-h composited municipal wastewater samples were collected from two communities (n = 8) in the southeastern US. Using isotope-dilution liquid chromatography-tandem mass spectrometry, results showed 16 metabolites were detected in wastewater samples, including indicators of exposure to acrolein, acrylonitrile, 1,3-butadiene, crotonaldehyde, n,n-dimethylformamide (DMF), ethylbenzene, nicotine, propylene oxide, styrene, tetrachloroethylene, toluene, and xylene. Additional metabolites qualitatively identified exposure to acrylamide and trichloroethylene. Community 1 (closer proximity to manufacturing facilities) had a greater number of detects (n = 36) and higher VOC loadings, 22,000 mg day^-1 per 1000 people, as compared to Community 2 (n = 28), 7100 mg day^-1 per 1000 people. Normalizing to nicotine consumption biomarkers to account for differences in smoking behaviors, Community 1 continued to have higher levels of propylene oxide, crotonaldehyde, DMF, and acrylonitrile exposures, VOCs generally sourced from manufacturing activities and vehicle emissions. This is the first study to utilize wastewater to detect urinary biomarkers of VOCs exposure. These preliminary results suggest the WBE approach as a potentially powerful tool to assess community health exposures to indoor and outdoor air pollutants.

Immunological Insights into Cigarette Smoking-Induced Cardiovascular Disease Risk

Smoking is one of the most prominent addictions of the modern world, and one of the leading preventable causes of death worldwide. Although the number of tobacco smokers is believed to be at a historic low, electronic cigarette use has been on a dramatic rise over the past decades. Used as a replacement for cigarette smoking, electronic cigarettes were thought to reduce the negative effects of burning tobacco. Nonetheless, the delivery of nicotine by electronic cigarettes, the most prominent component of cigarette smoke (CS) is still delivering the same negative outcomes, albeit to a lesser extent than CS. Smoking has been shown to affect both the structural and functional aspects of major organs, including the lungs and vasculature. Although the deleterious effects of smoking on these organs individually is well-known, it is likely that the adverse effects of smoking on these organs will have long-lasting effects on the cardiovascular system. In addition, smoking has been shown to play an independent role in the homeostasis of the immune system, leading to major sequela. Both the adaptive and the innate immune system have been explored regarding CS and have been demonstrated to be altered in a way that promotes inflammatory signals, leading to an increase in autoimmune diseases, inflammatory diseases, and cancer. Although the mechanism of action of CS has not been fully understood, disease pathways have been explored in both branches of the immune system. The pathophysiologically altered immune system during smoking and its correlation with cardiovascular diseases is not fully understood. Here we highlight some of the important pathological mechanisms that involve cigarette smoking and its many components on cardiovascular disease and the immune systems in order to have a better understanding of the mechanisms at play.

Cross-sectional and longitudinal associations of acrolein exposure with pulmonary function alteration: Assessing the potential roles of oxidative DNA damage, inflammation, and pulmonary epithelium injury in a general adult population

BACKGROUND

Acrolein is a significant high priority hazardous air pollutant with pulmonary toxicity and the leading cause of most noncancer adverse respiratory effects among air toxics that draws great attention. Whether and how acrolein exposure impacts pulmonary function remain inconclusive.

OBJECTIVES

To assess the association of acrolein exposure with pulmonary function and the underlying roles of oxidative DNA damage, inflammation, and pulmonary epithelium integrity.

METHODS

Among 3,279 Chinese adults from the Wuhan-Zhuhai cohort, associations of urinary acrolein metabolites (N-Acetyl-S-(2-carboxyethyl)-L-cysteine, CEMA; N-Acetyl-S-(3-hydroxypropyl)-L-cysteine, 3HPMA) as credible biomarkers of acrolein exposure with pulmonary function were analyzed by linear mixed models. Joint effects of biomarkers of oxidative DNA damage (8-hydroxy-deoxyguanosine), inflammation (C-reactive protein, CRP), and pulmonary epithelium integrity (Club cell secretory protein, CC16) with acrolein metabolites on pulmonary function and the mediating roles of these biomarkers were assessed. Besides, a subgroup (N = 138) was randomly recruited from the cohort to assess the stabilities of acrolein metabolites and their longitudinal associations with pulmonary function change in three years.

RESULTS

Significant inverse dose-response relationships between acrolein metabolites and pulmonary function were found. Each 10-fold increment in CEMA, 3HPMA, or ΣUACLM (CEMA + 3HPMA) was cross-sectionally related to a 68.56-, 40.98-, or 46.02-ml reduction in FVC and a 61.54-, 43.10-, or 50.14-ml reduction in FEV₁, respectively (P < 0.05). Furthermore, acrolein metabolites with fair to excellent stabilities were found to be longitudinally associated with pulmonary function decline in three years. Joint effects of acrolein metabolites with 8-hydroxy-deoxyguanosine, CRP, and CC16 on pulmonary function were identified. CRP significantly mediated 5.97% and 5.51% of CEMA-associated FVC and FEV₁ reductions, respectively. 8-hydroxy-deoxyguanosine significantly mediated 6.78%, 6.88%, and 7.61% of CEMA-, 3HPMA-, and ΣUACLM-associated FVC reductions, respectively.

CONCLUSIONS

Acrolein exposure of general adults was cross-sectionally and longitudinally related to pulmonary function decline, which was aggravated and/or partly mediated by oxidative DNA damage, inflammation, and pulmonary epithelium injury.

Association between exposure to organophosphorus pesticides and the risk of diabetes among US Adults: Cross-sectional findings from the National Health and Nutrition Examination Survey

OBJECTIVE

Organophosphorus pesticides (OPPs) are commonly used pesticides across the world, however there is little epidemiological evidence linking their exposure to diabetes. Hence, this study aimed at investigating the effect of OPP exposure on the prevalence of diabetes in American adults.

METHODS

Adults (≥20 years old) were eligible for this study from the National Health and Nutrition Examination Survey (NHANES). Multivariate logistic regression model was employed to explore the associations of six main urinary OPPs metabolites with diabetes. Subgroup analyses were performed by age and gender. Combined effect of OPPs metabolites on the overall association with diabetes was evaluated by weighted quantile sum regression (WQS). Furthermore, Bayesian kernel machine regression (BKMR) model was implemented to explore joint effect of multiple OPPs metabolites on diabetes.

RESULTS

Ultimately, 6,593 adults were included in our analysis. Of them, 1,044 participants were determined as diabetes patients. The results of logistic regression shown that urinary OPPs metabolites concentrations, whether taken as continuous variables or quantiles, were in positive correlation with diabetes. Notably, the p for trend of diethylphosphate (DEP), a kind of OPPs metabolites, was less than 0.05 indicated that a linear trend may exist between levels of DEP and prevalence of diabetes among adults while this trend was not obversed in other OPPs metabolites. In the WQS model, combined exposure of OPPs metabolites had a significantly positive association with diabetes (OR: 1.057; 95% CI: 1.002, 1.114) and diethylphosphate (36.84%) made the largest contributor to the WQS index. The result of BKMR also suggested a positive trend of association between mixed OPPs metabolites and diabetes.

CONCLUSION

Our results add credibility to the argument that OPP exposure might trigger diabetes. Certainly, prospective data are required to corroborate our findings.

Increased acrolein-DNA adducts in buccal brushings of e-cigarette users

DNA adducts are central in the mechanism of carcinogenesis by genotoxic agents. We compared levels of a DNA adduct of acrolein, a genotoxic carcinogen found in e-cigarette vapor, in oral cell DNA of e-cigarette users and non-users of any tobacco or nicotine product. e-Cigarette users and non-users visited our clinic once monthly for 6 months, and oral brushings and urine samples were collected. For this study, we analyzed oral cell DNA adducts from three monthly visits in e-cigarette users and non-users as confirmed by urinary cyanoethyl mercapturic acid and total nicotine equivalents. DNA was isolated from the oral brushings and analyzed by a validated liquid chromatography-nanoelectrospray ionization-high resolution tandem mass spectrometry method for the acrolein DNA adduct 8R/S-3-(2'-deoxyribos-1'-yl)-5,6,7,8-tetrahydro-8-hydroxypyrimido[1,2-a]purine-10-(3H)-one (γ-OH-Acr-dGuo). The median value of this DNA adduct in the e-cigarette users was 179 fmol/µmol dGuo (range 5.0 - 793 fmol/µmol dGuo) while that for non-users was 21.0 fmol/µmol dGuo (range 5.0 - 539 fmol/µmol dGuo), P = 0.001. These results demonstrate for the first time that e-cigarette users have elevated levels of a carcinogen-DNA adduct in their oral cells.

Particulate matters, aldehydes, and polycyclic aromatic hydrocarbons produced from deep-frying emissions: comparisons of three cooking oils with distinct fatty acid profiles

It is recognized that hazardous emissions produced from frying oils may be related to oil properties, particularly the fatty acid composition. However, investigations have been limited and partial. In this work, the emissions from deep-frying foods with three oils (palm, olive, and soybean oils) with distinct fatty acid profiles were comprehensively examined in a simulated kitchen, and the interrelationship among emitted substances, oil quality parameters, and fatty acids profiles was explored. Firstly, palm oil emitted the highest number concentration of total particle matters ((3895 ± 1796) × 103 #/cm3), mainly in the Aitken mode (20-100 nm). We observed a positive correlation between particle number concentration and levels of palmitic acid, a major saturated fatty acid (SAFA) (rs = 0.73, p < 0.05), and total polar compounds (TPC) (rs = 0.68, p < 0.05) in the fried oil, a degradation marker which was also positively correlated with that of black carbon (BC) (rs = 0.68, p < 0.05). Secondly, soybean oil emitted the highest level of gaseous aldehydes (3636 ± 607 μg/m3), including acrolein, propinoaldehyde, crotonaldehyde, hexanal, and trans-2-heptenal; the total aldehyde concentration were positively correlated with α-linolenic acid (ALA) percentage (rs = 0.78, p < 0.01), while hexanal and trans-2-heptenal were with linoleic acid (LA) (rs = 0.73 and 0.67, p < 0.05). LA and ALA were two major polyunsaturated fatty acids in non-tropical plant oils. Thirdly, palm oil emitted the most particle-bound polycyclic aromatic hydrocarbons (PAHs), and a positive association was discovered between two PAHs and SAFA percentage. Olive oil seems superior to soybean and palm oils with regards to toxic emissions during deep-frying.

Differences in Clinical Outcomes between Smokers and Non-Smokers infected with COVID-19

Cigarette smoking is a risk factor associated with different diseases, claiming millions of lives annually. Smoking status has been studied for a long time and proved to be a major cause of smokers' decreased immunity. In the present pandemic COVID-19 disease, there was an unclear belief about the effect of smoking on patients with COVID-19. Therefore, the current cross-sectional study aimed to evaluate the effect of cigarette smoking on the sequelae of COVID-19. This cross-sectional study involved 200 COVID-19 patients (114 males and 86 females) aged 13-77 years. A number of 87 patients were smokers, and the rest of them were non-smokers. All patients underwent a comprehensive laboratory assessment and diagnosis by full medical history by the physicians. The results indicated a significant difference (P<0.001) between smokers and non-smokers in terms of hypertension, anticoagulant, steroid therapy, pulmonary lesion, oxygen saturation, and duration of disease. As an overall conclusion, it can be stated that COVID-19 is less severe in smokers and they require less intensive treatment.

Apiaceous vegetables protect against acrolein-induced pulmonary injuries through modulating hepatic detoxification and inflammation in C57BL/6 male mice

Acrolein (Acr) is a reactive aldehyde in the environment. Acr causes oxidative stress and a cascade of catalytic events and has, thereby, been associated with increased risk of pulmonary diseases. Whether apiaceous vegetables (API) consumption can prevent Acr-induced pulmonary toxicity has not yet been explored hence, we investigated the effects of API on Acr-induced pulmonary damages in C57BL/6J mice. The mice were assigned into either negative control [NEG group; American Institute of Nutrition (AIN)-93G diet only], positive control (POS group; AIN-93G+Acr) or API intervention group (API group; AIN-93G+21% API+Acr). After 1 week of dietary intervention, the POS and API mice were exposed to Acr (10 µmol/kg body weight/day) for 5 days. During the exposure period, assigned diets remained the same. Prominent indicators lung of toxicity of POS mice were found, including mucus accumulation, macrophage infiltration, and hemorrhage, all of which were ameliorated by the API. Serum and lung inflammation markers, such as a tumor necrosis factor alpha were also increased by Acr while reduced by API. In the liver, API upregulated expression of glutathione S-transferases, which enhanced the metabolism of Acr into water-soluble 3-hydroxypropyl mercapturic acid for excretion. This is consistent with observed reductions in serum Acr-protein adducts. Taken together, our results suggest that API may provide protection against Acr-induced pulmonary damages and inflammation via enhancement of the hepatic detoxification of Acr.

Improving on estimates of the potential relative harm to health from using modern ENDS (vaping) compared to tobacco smoking

BACKGROUND

Although the harm to health from electronic nicotine delivery systems (ENDS) compared to smoked tobacco remains highly uncertain, society and governments still need to know the likely range of the relative harm to inform regulatory policies for ENDS and smoking.

METHODS

We identified biomarkers with specificity of association with different disease groupings e.g., volatile organic compound (VOCs) for chronic obstructive pulmonary disease; and tobacco-specific N´-nitrosamines (TSNAs) and polycyclic aromatic hydrocarbons (PAHs) for all cancers. We conducted a review of recent studies (post January 2017) that compared these biomarkers between people exclusively using ENDS and those exclusively smoking tobacco. The percentage differences in these biomarkers, weighted by study size and adjusted for acrolein from other sources, were used as a proxy for the assumed percentage difference in disease harm between ENDS and smoking. These relative differences were applied to previously modelled estimates of smoking-related health loss (in health-adjusted life-years; HALYs).

RESULTS

The respective relative biomarker levels (ENDS vs smoking) were: 28% for respiratory diseases (five results, three studies); 42% for cancers (five results, four studies); and 35% for cardiovascular (seven results, four studies). When integrated with the HALY impacts by disease, the overall harm to health from ENDS was estimated to be 33% that of smoking.

CONCLUSIONS

This analysis, suggests that the use of modern ENDS devices (vaping) could be a third as harmful to health as smoking in a high-income country setting. But this estimate is based on a limited number of biomarker studies and is best be considered a likely upper level of ENDS risk given potential biases in our method (i.e., the biomarkers used being correlated with more unaccounted for toxicants in smoking compared to with using ENDS).

Associations between urinary phthalate metabolite concentrations and markers of liver injury in the US adult population

BACKGROUND

Phthalates have been largely used for years in varieties of products worldwide. However, research on the joint toxic effect of various phthalates exposure on the liver is lacking.

OBJECTIVES

We aimed to assess exposure to phthalates on liver function tests (LFTs).

METHODS

This analysis included data on 6046 adults (≥20 years old) who participated in a National Health and Nutrition Examination Survey (NHANES) in 2007-2016. We employed linear regression and Bayesian kernel machine regression (BKMR), to explore the associations of urinary phthalate metabolites with 8 indicators of LFTs.

RESULTS

Di(2-ethylhexyl) phthalate (ΣDEHP) was found to be positively associated with serum alanine aminotransferase (ALT), gamma-glutamyl transferase (GGT) and alkaline phosphatase (ALP) (all P _FDR < 0.05). We found significant positive associations of ∑DEHP, mono-ethyl phthalate (MEP) and mono-(carboxyisononyl) phthalate (MCNP) with total bilirubin (TBIL) (all P _FDR < 0.05). ΣDEHP, mono-n-butyl phthalate (MBP), mono-(3-carboxypropyl) phthalate (MCPP) and mono-benzyl phthalate (MBzP) were negatively associated with serum ALB (all P _FDR < 0.05). The BKMR analyses showed a significantly positive overall effect on ALT, AST, ALP and TBIL levels with high concentrations of phthalate metabolites and a significantly negative overall effect on ALB and TP, when all the chemicals at low concentrations.

CONCLUSIONS

Our results add novel evidence that exposures to phthalates might be adversely associated with the indicators of LTFs, indicating the potential toxic effect of phthalate exposures on the human liver.

Updated Health and Cost Impacts of Electronic Nicotine Delivery Systems, Using Recent Estimates of Relative Harm for Vaping Compared to Smoking

BACKGROUND

Measuring population health and costs effects of liberalizing access to electronic nicotine delivery systems (ENDS) is an evolving field with high persisting uncertainty. A critical area of uncertainty for policy-makers are estimates of net harms from ENDS relative to cigarettes, therefore, we model these harms using updated estimates incorporating disease specificity.

METHODS

We use updated estimates of relative harm of vaping vs smoking, based upon relevant biomarker studies to model the impact of liberalizing access to ENDS in New Zealand (NZ), relative to a ban (where ENDS are not legally available), in an existing proportional multi-state life-table model of 16 tobacco-related diseases.

RESULTS

This modeling suggests that ENDS liberalization results in an expected gain of 195 000 quality-adjusted life-years (QALYs) over the remainder of the NZ population's lifespan. There was wide uncertainty in QALYs gained (95% uncertainty interval [UI] = -8000 to 406 000) with a 3.2% probability of net health loss (based upon the number of simulation runs returning positive QALY gains). The average per capita health gain was 0.044 QALYs (equivalent to an extra 16 days of healthy life). Health system cost-savings were expected to be NZ$2.8 billion (US$2.1 billion in 2020 US$; 95%UI: -0.3 to 6.2 billion [2011 NZ$]), with an estimated 3% chance of a net increase in per capita cost.

CONCLUSIONS

This updated modeling around liberalizing ENDs in NZ, still suggests likely net health and cost-saving benefits-but of lesser magnitude than previous work and with a small possibility of net harm to population health.

IMPLICATIONS

This study found evidence using updated biomarker studies that ENDS liberalization could result in QALY gains across the New Zealand population lifespan that are also cost-saving to the health system. Governments should include the information from these types of modeling studies in their decision-making around potentially improving access to ENDS for existing smokers, while at the same further reducing access to tobacco.

Assessment of the potential vaping-related exposure to carbonyls and epoxides using stable isotope-labeled precursors in the e-liquid

The formation of carbonyls and epoxides in e-cigarette (EC) aerosol is possible due to heating of the liquid constituents. However, high background levels of these compounds have inhibited a clear assessment of exposure during use of ECs. An EC containing an e-liquid replaced with 10% of ¹³C-labeled propylene glycol and glycerol was used in a controlled use clinical study with 20 EC users. In addition, five smokers smoked cigarettes spiked with the described e-liquid. Seven carbonyls (formaldehyde, acetaldehyde, acrolein, acetone, crotonaldehyde, methacrolein, propionaldehyde) were measured in the aerosol and the mainstream smoke. Corresponding biomarkers of exposure were determined in the user’s urine samples. ¹³C-labeled formaldehyde, acetaldehyde and acrolein were found in EC aerosol, while all seven labeled carbonyls were detected in smoke. The labeled biomarkers of exposure to formaldehyde (¹³C-thiazolidine carboxylic acid and ¹³C-N-(1,3-thiazolidine-4-carbonyl)glycine), acrolein (¹³C₃-3-hydroxypropylmercapturic acid) and glycidol (¹³C₃-dihydroxypropylmercapturic acid) were present in the urine of vapers indicating an EC use-specific exposure to these toxicants. However, other sources than vaping contribute to a much higher extent by several orders of magnitude to the overall exposure of these toxicants. Comparing data for the native (unlabeled) and the labeled (exposure-specific) biomarkers revealed vaping as a minor source of user’s exposure to these toxicants while other carbonyls and epoxides were not detectable in the EC aerosol.

Exposure to Nicotine and Toxicants Among Dual Users of Tobacco Cigarettes and E-Cigarettes: Population Assessment of Tobacco and Health (PATH) Study, 2013-2014

INTRODUCTION

Concurrent use of tobacco cigarettes and e-cigarettes ("dual use") is common among tobacco users. Little is known about differences in demographics and toxicant exposure among subsets of dual users.

AIMS AND METHODS

We analyzed data from adult dual users (current every/some day users of tobacco cigarettes and e-cigarettes, n = 792) included in the PATH Study Wave 1 (2013-2014) and provided urine samples. Samples were analyzed for biomarkers of exposure to nicotine and selected toxicants (tobacco-specific nitrosamine NNK [NNAL], lead, cadmium, naphthalene [2-naphthol], pyrene [1-hydroxypyrene], acrylonitrile [CYMA], acrolein [CEMA], and acrylamide [AAMA]). Subsets of dual users were compared on demographic, behavioral, and biomarker measures to exclusive cigarette smokers (n = 2411) and exclusive e-cigarette users (n = 247).

RESULTS

Most dual users were predominant cigarette smokers (70%), followed by daily dual users (13%), non-daily concurrent dual users (10%), and predominant vapers (7%). Dual users who smoked daily showed significantly higher biomarker concentrations compared with those who did not smoke daily. Patterns of e-cigarette use had little effect on toxicant exposure. Dual users with high toxicant exposure were generally older, female, and smoked more cigarettes per day. Dual users who had low levels of biomarkers of exposure were generally younger, male, and smoked non-daily.

CONCLUSIONS

In 2013-2014, most dual users smoked cigarettes daily and used e-cigarettes occasionally. Cigarette smoking appears to be the primary driver of toxicant exposure among dual users, with little-to-no effect of e-cigarette use on biomarker levels. Results reinforce the need for dual users to stop smoking tobacco cigarettes to reduce toxicant exposure.

IMPLICATIONS

With considerable dual use of tobacco cigarettes and e-cigarettes in the United States, it is important to understand differences in toxicant exposure among subsets of dual users, and how these differences align with user demographics. Findings suggest most dual users smoke daily and use e-cigarettes intermittently. Low exposure to toxicants was most common among younger users, males, and intermittent smokers; high exposure to toxicants was most common among older users, females, and heavier cigarette smokers. Results underscore the heterogeneity occurring within dual users, and the need to quit smoking cigarettes completely in order to reduce toxicant exposure.

Exposure to volatile organic compounds - acrolein, 1,3-butadiene, and crotonaldehyde - is associated with vascular dysfunction

BACKGROUND

Cardiovascular disease (CVD) is the leading cause of mortality worldwide. Exposure to air pollution, specifically particulate matter of diameter ≤2.5 μm (PM2.5), is a well-established risk factor for CVD. However, the contribution of gaseous pollutant exposure to CVD risk is less clear.

OBJECTIVE

To examine the vascular effects of exposure to individual volatile organic compounds (VOCs) and mixtures of VOCs.

METHODS

We measured urinary metabolites of acrolein (CEMA and 3HPMA), 1,3-butadiene (DHBMA and MHBMA3), and crotonaldehyde (HPMMA) in 346 nonsmokers with varying levels of CVD risk. On the day of enrollment, we measured blood pressure (BP), reactive hyperemia index (RHI - a measure of endothelial function), and urinary levels of catecholamines and their metabolites. We used generalized linear models for evaluating the association between individual VOC metabolites and BP, RHI, and catecholamines, and we used Bayesian Kernel Machine Regression (BKMR) to assess exposure to VOC metabolite mixtures and BP.

RESULTS

We found that the levels of 3HPMA were positively associated with systolic BP (0.98 mmHg per interquartile range (IQR) of 3HPMA; CI: 0.06, 1.91; P = 0.04). Stratified analysis revealed an increased association with systolic BP in Black participants despite lower levels of urinary 3HPMA. This association was independent of PM2.5 exposure and BP medications. BKMR analysis confirmed that 3HPMA was the major metabolite associated with higher BP in the presence of other metabolites. We also found that 3HPMA and DHBMA were associated with decreased endothelial function. For each IQR of 3HPMA or DHBMA, there was a -4.4% (CI: -7.2, -0.0; P = 0.03) and a -3.9% (CI: -9.4, -0.0; P = 0.04) difference in RHI, respectively. Although in the entire cohort the levels of several urinary VOC metabolites were weakly associated with urinary catecholamines and their metabolites, in Black participants, DHBMA levels showed strong associations with urinary norepinephrine and normetanephrine levels.

DISCUSSION

Exposure to acrolein and 1,3-butadiene is associated with endothelial dysfunction and may contribute to elevated risk of hypertension in participants with increased sympathetic tone, particularly in Black individuals.

Assessment of Serum Concentrations of 12 Aldehydes in the U.S. Population from the 2013-2014 National Health and Nutrition Examination Survey

Aldehydes are known carcinogens and irritants that can negatively impact health. They are present in tobacco smoke, the environment, and food. The prevalence of aldehyde exposure and potential health impact warrants a population-wide study of serum aldehydes as exposure biomarkers. We analyzed 12 aldehydes in sera collected from 1843 participants aged 12 years or older in the 2013-2014 National Health and Nutrition Examination Survey. Several aldehydes were detected at high rates, such as isopentanaldehyde (99.2%) and propanaldehyde (88.3%). We used multiple linear regression models to examine the impact of tobacco smoke and dietary variables on serum concentrations of isopentanaldehyde and propanaldehyde. Although 12 serum aldehydes were analyzed and compared to tobacco smoke exposure, only isopentanaldehyde and propanaldehyde showed any significant association with tobacco smoke exposure. Survey participants who smoked 1-10 cigarettes per day (CPD) had 168% higher serum isopentanaldehyde and 28% higher propanaldehyde compared with nonusers. Study participants who smoked 11-20 CPD had higher serum isopentanaldehyde (323%) and propanaldehyde (70%). Similarly, study participants who smoked >20 CPD had 399% higher serum isopentanaldehyde and 110% higher serum propanaldehyde than nonexposed nonusers. The method could not, however, differentiate between nonexposed nonusers and nonusers exposed to secondhand smoke for either of these two aldehydes. No dietary variables were consistently predictive of serum isopentanaldehyde and propanaldehyde concentrations. This report defines baseline concentrations of serum aldehydes in the U.S. population and provides a foundation for future research into the potential health effects of aldehydes. In addition, this study suggests that tobacco smoke is a significant source of exposure to some aldehydes such as isopentanaldehyde and propanaldehyde.

In vitro dosimetry analyses for acrolein exposure in normal human lung epithelial cells and human lung cancer cells

Establishing accurate dosimetry is important for assessing the toxicity of xenobiotics as well as for comparing responses between different test systems. In this study, we used acrolein as a model toxicant and defined the concentration-response relationships of the key adverse responses in normal human bronchial epithelial (NHBE) cells and human mucoepidermoid pulmonary carcinoma (NCI-H292) cells. Direct trace analysis of intracellular free acrolein is extremely challenging, if not impossible. Therefore, we developed a new method for indirectly estimating the intracellular uptake of acrolein. A 10-min treatment was employed to capture the rapid occurrence of the key alkylation reactions of acrolein. Responses, including protein carbonylation, GSH depletion, and GSH-acrolein (GSH-ACR) adduct formation, were all linearly correlated with acrolein uptake in both cell types. Compared to the NCI-H292 mucoepidermoid carcinoma cells, NHBE cells were more sensitive to acrolein exposure. Furthermore, results from the time-course studies demonstrated that depletion and conjugation of GSH were the primary adverse events and directly associated with the cytotoxicity induced by acrolein. In summary, these data suggest that cell susceptibility to acrolein exposure is closely associated with acrolein uptake and formation of GSH-ACR adducts. The dosimetric analysis presented in this study may provide useful information for computational modeling and risk assessment of acrolein using different test systems.

Smoking and COVID-19: A Scoping Review

Smoking affects a person's overall health and damages nearly every organ of the body. Since smoking tobacco affects and damages the lungs, it increases the risk of respiratory infections and makes it easier for the coronavirus disease (COVID-19) to invade the lung tissue, causing more severe symptoms and increasing the risk of death. However, debates are still ongoing as to the effect of cigarette smoking on vulnerability to COVID-19. Some studies, where active smokers were underrepresented among patients with COVID-19, claimed that a "smoker's paradox" may exist in COVID-19 and that smokers are protected from infection and severe complications of COVID-19. However, other studies reported the opposite trend. The objective of this study is to review the findings of epidemiological and in vitro studies about the association between smoking and the risk of contracting COVID-19, taking into account disease severity. Several epidemiological studies have found a higher smoking prevalence among COVID-19 infected patients. Also, studies had shown that people with respiratory diseases caused by tobacco use are at higher risk of developing severe COVID-19 symptoms. Studies have shown that in vitro, the acute exposure allows for more severe proximal airway epithelial disease from SARS-CoV-2 by reducing the mucosal innate immune response and the proliferation of airway basal stem cells and has implications for disease spread and severity in people exposed to cigarette smoke, with a more severe viral infection and cell death. Smoker patients with different comorbidities are at higher risk of contracting the COVID-19 virus and have a worse prognosis for the virus as well as for their comorbidities. Further investigations of the interaction between smoking and COVID-19 are warranted to accurately assess the risk of contracting COVID-19 among smokers, and the progression to mechanical ventilation or death in patients who suffer from it.

Acrolein and other toxicant exposures in relation to cardiovascular disease among marijuana and tobacco smokers in a longitudinal cohort of HIV-positive and negative adults

BACKGROUND

Marijuana smoke contains some of the same toxicants present in tobacco smoke. Marijuana smoking is prevalent among HIV+ individuals, but few studies have characterized smoke-related toxicants or associated health outcomes in exclusive marijuana users.

METHODS

This longitudinal study included 245 participants over age 40 (76% HIV+). 33 plasma and 28 urine metabolites of nicotine, ∆-9-trans-tetrahydrocannabinol, polycyclic aromatic hydrocarbons, and volatile organic compounds were assayed by liquid or gas chromatography/mass spectrometry. Exposures and health outcomes were assessed from surveys and medical records.

FINDINGS

At baseline, 18% of participants were marijuana-only smokers, 20% tobacco-only smokers, and 24% dual marijuana-tobacco smokers (median (IQR) age 53 (47-60) years, 78% male, 54% white race). Marijuana smoking was independently associated with elevated plasma naphthalenes, 2-hydroxyfluorene sulfate, 4-vinylphenol sulfate, and o-cresol sulfate (p<0·05) and urine acrylonitrile and acrylamide metabolites (p<0·05), but levels were lower than those associated with tobacco smoking. Acrolein metabolite N-Acetyl-S-(3-hydroxypropyl)-l-cysteine (3HPMA) was significantly elevated in plasma and urine in tobacco-only and dual but not marijuana-only smokers, and correlated with nicotine metabolites (p<0·05). The highest tertile of 3HPMA was associated with increased cardiovascular disease diagnoses independent of tobacco smoking, traditional risk factors, and HIV status (odds ratio [95% CI] 3·34 [1·31-8·57]; p = 0·012).

INTERPRETATION

Smoke-related toxicants, including acrylonitrile and acrylamide metabolites, are detectable in exclusive marijuana smokers, but exposures are lower compared with tobacco or dual smokers. Acrolein exposure is increased by tobacco smoking but not exclusive marijuana smoking in HIV+ and HIV- adults, and contributes to cardiovascular disease in tobacco smokers.

FUNDING

U.S. NIH.

Emerging Role of Mitophagy in Inflammatory Diseases: Cellular and Molecular Episodes

Mitochondria are the crucial regulators for the major source of ATP for different cellular events. Due to damage episodes, mitochondria have been established for a plethora ofalarming signals of stress that lead to cellular deterioration, thereby causing programmed cell death. Defects in mitochondria play a key role in arbitrating pathophysiological machinery with recent evince delineating a constructive role in mitophagy mediated mitochondrial injury. Mitophagy has been known for the eradication of damaged mitochondria via the autophagy process. Mitophagy has been investigated as an evolutionarily conserved mechanism for mitochondrial quality control and homeostasis. Impaired mitophagy has been critically linked with the pathogenesis of inflammatory diseases. Nevertheless, the exact mechanism is not quite revealed, and it is still debatable. The purpose of this review was to investigate the possible role of mitophagy and its associated mechanism in inflammation-mediated diseases at both the cellular and molecular levels.

Environmental chemical exposures in the urine of dogs and people sharing the same households

Introduction:

Urothelial carcinoma (UCC) develops in both humans and dogs and tracks to regions of high industrial activity. We hypothesize that dogs with UCC may act as sentinels for human urothelial carcinogen exposures. The aim of this pilot study was to determine whether healthy people and dogs in the same households share urinary exposures to potentially mutagenic chemical carcinogens.

Methods:

We measured urinary concentrations of acrolein (as its metabolite 3-HPMA), arsenic species, 4-aminobiphenyl, and 4-chlorophenol (a metabolite of the phenoxyherbicide 2,4-D) in healthy dogs and their owners. We assessed possible chemical sources through questionnaires and screened for urothelial DNA damage using the micronucleus assay.

Results:

Biomarkers of urinary exposure to acrolein, arsenic, and 4-chlorophenol were found in the urine of 42 pet dogs and 42 owners, with 4-aminobiphenyl detected sporadically. Creatinine-adjusted urinary chemical concentrations were significantly higher, by 2.8- to 6.2-fold, in dogs compared to humans. Correlations were found for 3-HPMA (r = 0.32, P = 0.04) and monomethylarsonic acid (r = 0.37, P = 0.02) between people and their dogs. Voided urothelial cell yields were inadequate to quantify DNA damage, and questionnaires did not reveal significant associations with urinary chemical concentrations.

Conclusions:

Healthy humans and pet dogs have shared urinary exposures to known mutagenic chemicals, with significantly higher levels in dogs. Higher urinary exposures to acrolein and arsenic in dogs correlate to higher exposures in their owners. Follow-up studies will assess the mutagenic potential of these levels in vitro and measure these biomarkers in owners of dogs with UCC.

A review of the analysis of biomarkers of exposure to tobacco and vaping products

Quantification of exposure to different chemicals from both combustible cigarettes and vaping products is important in providing information on the potential health risks of these products. To assess the exposure to tobacco products, biomarkers of exposure (BOEs) are measured in a variety of biological matrices. In this review paper, current knowledge on analytical methods applied to the analysis of biomarkers of exposure to tobacco products is discussed. Numerous sample preparation techniques are available for the extraction and sample clean up for the analysis of BOEs to tobacco and nicotine delivery products. Many tobacco products-related exposure biomarkers have been analyzed using different instrumental techniques, the most common techniques being gas and liquid chromatography coupled with mass spectrometry (GC-MS, GC-MS/MS and LC-MS/MS). To assess exposure to emerging tobacco products and study exposure in dual tobacco users, the list of biomarkers analyzed in urine samples has been expanded. Therefore, the current state of the literature can be used in preparing a preferred list of biomarkers based on the aim of each study. The information summarized in this review is expected to be a handy tool for researchers involved in studying exposures to tobacco products, as well as in risk assessment of biomarkers of exposure to vaping products.

Acrolein-Trapping Mechanism of Theophylline in Green Tea, Coffee, and Cocoa: Speedy and Successful

Increasing evidence has identified the unsaturated aldehyde acrolein (ACR) as the potential factor that causes deoxyribonucleic acid cross-linking and the development of chronic diseases. The objective of this study was to investigate the mechanism by which theophylline (TP) scavenges ACR for the first time. TP efficiently scavenged ACR through forming adducts, which was demonstrated in a system in which TP was incubated with ACR at different ratios for different times for liquid chromatography with tandem mass spectrometry. Then, the mono- and di-ACR-TP adducts were purified, and their structures were elucidated by high-resolution mass spectrometry and nuclear magnetic resonance analysis. We found that the ACR residue on mono-ACR-TP further trapped one more ACR and formed di-ACR-TP adducts. Furthermore, mono- and di-ACR-TP had similar time-dependent ACR-scavenging activity to TP. Finally, we demonstrated that green tea, coffee, and cocoa inhibited ACR by trapping ACR to form mono- and di-ACR-TP adducts during the incubation of green tea, coffee, and cocoa with ACR.

Tobacco Smoke and Endothelial Dysfunction: Role of Aldehydes?

PURPOSE OF REVIEW

Tobacco smoking is the most significant modifiable risk factor in the development of cardiovascular disease (CVD). Exposure to mainstream cigarette smoke (MCS) is associated with CVD through the development of endothelial dysfunction, a condition characterized by an imbalance of vasoactive factors in the vasculature. This dysfunction is thought to be induced in part by aldehydes generated at high levels in MCS.

RECENT FINDINGS

Electronic cigarettes (e-cigs) may also pose CVD risk. Although the health effects of e-cigs are still largely unknown, the presence of aldehydes in e-cig aerosol suggests that e-cigs may induce adverse cardiovascular outcomes similar to those seen with MCS exposure. Herein, we review studies of traditional and emerging tobacco product use, shared harmful and potentially harmful constituents, and measures of biomarkers of harm (endothelial dysfunction) to examine a potential and distinct role of aldehydes in cardiovascular harm associated with cigarette and e-cig use.

Quantitation by liquid chromatography-nanoelectrospray ionization-high resolution tandem mass spectrometry of DNA adducts derived from methyl glyoxal and carboxyethylating agents in leukocytes of smokers and non-smokers

A liquid chromatograpy-nanoelectrospray ionization-high resolution tandem mass spectrometry (LC-NSI-HRMS/MS) method was developed for quantitation of the DNA adducts 7-(2'-carboxyethyl)guanine (7-2'-CEG) and N2-(1'-carboxyethyl)guanine (N2-1'-CEG), as their methyl esters, in human leukocyte DNA from smokers and non-smokers. 7-2'-CEG has been previously identified in all human liver samples analyzed and is formed from an unknown carboxyethylating agent while N2-1'-CEG is formed from the advanced glycation endproduct methyl glyoxal. The method was applied for the analysis of these two DNA adducts in leukocyte DNA from 20 smokers and 20 non-smokers, in part to test the hypothesis that 7-2'-CEG could be formed by endogenous nitrosation, as previously observed in rats treated with nitrosodihydrouracil and nitrite. Levels of 7-2'-CEG (mean ± S.D.) were 0.6 ± 0.2 pmol/μmol dG in smokers and 0.5 ± 0.2 pmol/μmol dG in non-smokers, while those of N2-1'-CEG were 4.5 ± 1.9 pmol/μmol dG in smokers and 4.6 ± 2 pmol/μmol dG in non-smokers. These results did not support our hypothesis that endogenous nitrosation of dihydrouracil in smokers leads to higher levels of 7-2'-CEG in leukocyte DNA than in non-smokers. However the study provides the first data on levels of these DNA adducts in human leukocyte DNA, and the LC-NSI-HRMS/MS method developed for their quantitation could be important for future studies of DNA damage by methyl glyoxal.

Quantitative Liquid Chromatography-Nanoelectrospray Ionization-High-Resolution Tandem Mass Spectrometry Analysis of Acrolein-DNA Adducts and Etheno-DNA Adducts in Oral Cells from Cigarette Smokers and Nonsmokers

Cigarette smoking is an important source of human exposure to toxicants and carcinogens and contributes significantly to cancer morbidity and mortality worldwide. Acrolein, a widespread environmental pollutant, is present in relatively high amounts in cigarette smoke and can react directly with DNA to form DNA adducts, which serve as important biomarkers for the assessment of exposure to acrolein and its potential role in smoking related cancer. Etheno-DNA adducts are promutagenic DNA lesions that can derive from exogenous chemicals as well as endogenous sources, including lipid peroxidation. In this study, we developed a combined method for the quantitation of (6R/S)-3-(2'-deoxyribos-1'-yl)-5,6,7,8,-tetrahydro-6-hydroxypyrimido[1,2-a]purine-10(3H)-one (α-OH-Acr-dGuo), (8R/S)-3-(2'-deoxyribos-1'-yl)-5,6,7,8,-tetrahydro-8-hydroxypyrimido[1,2-a]purine-10(3H)-one (γ-OH-Acr-dGuo), 1,N6-etheno-dAdo (εdAdo), and 3,N4-etheno-dCyd (εdCyd) adducts in oral rinse and cytobrush DNA from smokers and nonsmokers by liquid chromatography-nanoelelctrospray ionization-high-resolution tandem mass spectrometry (LC-NSI-HRMS/MS). For oral rinse samples, there was a statistically significant difference between the levels of α-OH-Acr-dGuo, γ-OH-Acr-dGuo, εdAdo, and εdCyd in smokers (12.1 ± 17.9, 163 ± 227, 182 ± 568, and 194 ± 400 adducts/109 nucleotides, respectively) and nonsmokers (1.85 ± 2.08, 5.95 ± 4.23, 7.69 ± 11.7, and 6.07 ± 10.9 adducts/109 nucleotides, respectively). For cytobrush samples, there was a statistically significant difference between the levels of γ-OH-Acr-dGuo and εdAdo in smokers (259 ± 540 and 82.9 ± 271 adducts/109 nucleotides, respectively) and nonsmokers (7.37 ± 5.09 and 16.2 ± 30.2 adducts/109 nucleotides, respectively) but not for α-OH-Acr-dGuo and εdCyd. Our results demonstrate that oral mucosa cells are an excellent source of material for evaluating DNA adducts to be used as biomarkers of tobacco smoke exposure and molecular changes potentially related to cancer.

Levels of a mixture of heavy metals in blood and urine and all-cause, cardiovascular disease and cancer mortality: A population-based cohort study

People are exposed to heavy metals in many ways during the course of their daily life. However, the effect of mixtures of heavy metals on mortality in the U.S. general population is unclear. We aimed to investigate the association between heavy metal concentrations (blood [lead, cadmium and mercury] and urine [barium, cadmium, cobalt, cesium, molybdenum, lead, antimony, titanium, tungsten and uranium]) and all-cause, cardiovascular disease (CVD) and cancer mortality. Data were obtained from the National Health and Nutrition Examination Survey (NHANES) 1999-2014. Poisson regression was performed to analyze the associations between single-metal and multimetal exposure and mortality. The following variables were adjusted as covariates: demographic variables (age, education, sex and ethnicity), anthropometric variables (body mass index), lifestyle variables (family income, serum cotinine category and physical activity) and medical comorbidities (CVD and diabetes). A total of 26,056 subjects from the NHANES were included in the present study (mean follow-up, 7.4 years). The age of the participants ranged from 20 to 85 years. The blood metal mixture was associated with all-cause mortality (RR = 1.38, 95% CI 1.25, 1.51), CVD mortality (RR = 1.43, 95% CI 1.06, 1.94) and cancer mortality (RR = 1.41, 95% CI 1.12, 1.76) and cadmium had the highest weight in the weighted quantile sum (WQS) regression for all associations. The urinary metal mixture was associated with an increased risk of all-cause (RR = 1.48, 95% CI 1.30, 1.68) and cancer mortality (RR = 1.60, 95% CI 1.02, 2.52). Sex differences were found in the associations of both blood and urine metal mixtures with cancer mortality. Our study suggests a potential positive association for the concentrations of heavy metal mixtures with overall, CVD and cancer mortality based on a large sample of the U.S. general population. Nevertheless, further studies are needed to confirm these important findings.

Post-transcriptional air pollution oxidation to the cholesterol biosynthesis pathway promotes pulmonary stress phenotypes

The impact of environmentally-induced chemical changes in RNA has been fairly unexplored. Air pollution induces oxidative modifications such as 8-oxo-7,8-dihydroguanine (8-oxoG) in RNAs of lung cells, which could be associated with premature lung dysfunction. We develop a method for 8-oxoG profiling using immunocapturing and RNA sequencing. We find 42 oxidized transcripts in bronchial epithelial BEAS-2B cells exposed to two air pollution mixtures that recreate urban atmospheres. We show that the FDFT1 transcript in the cholesterol biosynthesis pathway is susceptible to air pollution-induced oxidation. This process leads to decreased transcript and protein expression of FDFT1, and reduced cholesterol synthesis in cells exposed to air pollution. Knockdown of FDFT1 replicates alterations seen in air pollution exposure such as transformed cell size and suppressed cytoskeleton organization. Our results argue of a possible novel biomarker and of an unseen mechanism by which air pollution selectively modifies key metabolic-related transcripts facilitating cell phenotypes in bronchial dysfunction.

Gonzales-Rivera et al. develop a method for 8-oxoG profiling using immunocapturing and RNA sequencing. They show that the FDFT1 transcript is susceptible to air pollution-induced oxidation, after identifying 42 transcripts that are differentially oxidized in bronchial epithelial BEAS-2B cells under air pollution conditions relative to clean air. FDFT1 oxidation affects cholesterol synthesis pathway, leading to phenotypes associated with several lung diseases.