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

Beyond the puff: health consequences of vaping

Electronic nicotine delivery systems (ENDS) arrived on the U.S. market in 2007 and rapidly grew in popularity as a harm reduction tool for traditional cigarette users. While initially marketed as a healthier alternative to combustible cigarettes, the unique mixture of chemical constituents in ENDS products and their emissions have led to rising concern about their safety and the long-term health implications. Given the lack of long-term, epidemiological research on the health effects of these products, recent research has sought to understand the impacts on cellular components and gain understanding of acute effects to inform potential chronic health implications. Studies have demonstrated the deleterious effects the use of ENDS has on the oral cavity, respiratory, and cardiovascular systems. ENDS use has been linked to gingival inflammation and alterations in the oral microbiome contributing to periodontal disease. Further, the presence of heavy metals and other constituents in ENDS emissions contribute to aberrant oxidative stress and inflammation within the lung, contributing to alterations in functional lung capacity and respiratory symptoms in ENDS users. In addition, harmful components of ENDS emissions make their way to the circulatory system, leading to detrimental impacts in cardiovascular functioning such as a rise in blood pressure, impaired vascular functioning, and increased heart rate, all of which are known to underscore long-term cardiovascular ailments. This review will provide an in-depth discussion of the current literature available on the consequences of ENDS use on the oral cavity, respiratory, and cardiovascular systems as well as provide insight into long-term implications that may result.

Trimester-specific associations of exposure to epoxide alkanes, alkenals, and 1,3-butadiene with preschool children's intellectual development: A birth cohort study in Wuhan, China

The impact of prenatal exposure to contaminants with neurotoxicity like epoxide alkanes (ethylene oxide, propylene oxide), alkenals (acrolein, crotonaldehyde), and 1,3-butadiene on children's intellectual development remains underreported, and related sensitive window is of interest. In this cohort study, metabolites of these contaminants were measured in 3,081 urine samples from 1,027 pregnant women across three trimesters. Children's intelligence quotient was evaluated at 4-6 years old. Generalized estimating equation models showed that higher urinary concentrations of 2-hydroxypropyl mercapturic acid (a metabolite of propylene oxide), 3-hydroxypropyl mercapturic acid (HPMMA, a metabolite of crotonaldehyde), and the sum of acrolein metabolites in the first trimester were associated with lower visual spatial index (VSI), working memory index (WMI), or processing speed index scores. Quantile g-computation models revealed that co-exposure to these contaminants in the first trimester were associated with lower VSI (β = -0.98, 95 % CI: -1.94, -0.03) and WMI (β = -0.86, 95 % CI: -1.66, -0.06) scores, with HPMMA as the major contributor. These results suggested that early pregnancy could be a sensitive window during which exposure to propylene oxide, crotonaldehyde, and acrolein may impair offspring's intellectual development.

Association between exposure to volatile organic compounds and allergic symptoms: Emphasis on the cocktail effect and potential mechanisms of toxicity

Assessment of the influence of volatile organic compounds (VOCs) on allergic symptoms is usually limited to the effect of individual VOC exposure, with fewer substances being considered. Furthermore, the impact of mixed VOC exposure on allergic symptoms has rarely been addressed. This study aimed to investigate the association between mixed VOC exposure and allergic symptoms while identifying key risk factors. A total of 1901 participants from the 2005-2006 National Health and Nutrition Examination Survey (NHANES) were included. Four statistical models were employed to assess the effect of VOC exposure on allergic symptoms. The potential pathways and key targets were identified using the network pharmacology analysis methods. Positive correlations were observed between mixed VOC exposure and wheezing and eczema. N-acetyl-S-(2-carbamoylethyl)-L-cysteine (AAMA) and N-acetyl-s-(3-hydroxypropyl-1-methyl)-L-cysteine (HPMM) were recognized as significant risk factors for wheezing and eczema. The network pharmacology analysis revealed significant enrichments of the PI3K-Akt and MAPK signaling pathways between AAMA and wheezing, as well as significant enrichments of the interleukin (IL)-17 and tumor necrosis factor (TNF) signaling pathways between HPMM and eczema. Consequently, our study suggested that VOC exposure in human results in oxidative stress and inflammatory responses, increasing the risk of allergic symptoms.

Exposure to volatile organic compounds and chronic respiratory disease mortality, a case-cohort study

BACKGROUND

Chronic respiratory diseases (CRDs) are the third leading cause of death worldwide. Data of the associations between specific volatile organic compounds (VOCs), a major component of air pollution and tobacco smoke, and subsequent CRD mortality in the general population are scarce.

METHODS

In a case-cohort analysis within the population-based Golestan cohort study (n = 50045, aged 40-75 years, 58% women, enrollment: 2004-2008, northeastern Iran), we included all participants who died from CRD during follow-up through 2018 (n = 242) as cases and stratified them into 16 strata defined by age, sex, residence, and tobacco smoking. Subcohort participants (n = 610) were randomly selected from all eligible cohort participants in each stratum, and sampling fractions were calculated. Baseline urine samples were used to measure 20 VOCs using ultra high-performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry. After excluding participants with previous history of CRDs, we used stratified Cox regression models weighted by the inverse sampling fractions (i.e. inverse probability weighting) adjusted for potential confounders, including urinary cotinine and pack-years of smoking, to calculate hazard ratios (HR) for the associations between biomarker tertiles and CRD mortality.

RESULTS

Data from 545 non-case, sub-cohort participants and 149 cases (69.1% chronic obstructive pulmonary disease, 13.4% asthma, 17.5% other CRDs) were assessed in this study. During a follow-up of 10.5 years, associations [2nd and 3rd vs. 1st tertiles, HR (95% confidence interval), p for trend] were observed between metabolites of acrolein [1.56 (0.64,3.79), 3.53 (1.53,8.16), 0.002] and styrene/ethylbenzene [1.17 (0.53,2.60), 3.24 (1.37,7.66), 0.005] and CRD mortality, which persisted after excluding the first four years of follow-up.

CONCLUSION

Our findings support prior research suggesting respiratory toxicity of VOCs. Further investigation and monitoring of these compounds, especially acrolein and styrene/ethylbenzene, as CRD risk factors, are recommended.

Acrolein scavengers and detoxification: From high-throughput screening of flavonoids to mechanistic study of epigallocatechin gallate

Acrolein (ACR) is a widespread, highly toxic substance that poses significant health risks. Flavonoids have been recognized as effective ACR scavengers, offering a possible way to reduce these risks. However, the lack of specific high-throughput screening methods has limited the identification of ACR scavengers, and their actual detoxifying capacity on ACR remains unknown. To address this, we developed a high-throughput screening platform to assess the ACR scavenging capacity of 322 flavonoids. Our results showed that 80.7 % of the flavonoids could scavenge ACR, but only 34.4 % exhibited detoxifying effects in an ACR-injured QSG7701 cell model. Some flavonoids even increased toxicity. Structure-activity relationship (SAR) analysis indicated that galloyl and pyrogallol units enhance scavenging but worsen ACR-induced cytotoxicity. Further investigation revealed that epigallocatechin gallate (EGCG) could exacerbate ACR-induced redox disorder, leading to cell apoptosis. Our findings provide crucial data on the scavenging and detoxifying capacities of 322 flavonoids, highlighting that ACR scavengers might not mitigate ACR-induced toxicity and could pose additional safety risks.

Gas6-Axl signal promotes indoor VOCs exposure-induced pulmonary fibrosis via pulmonary microvascular endothelial cells-fibroblasts cross-talk

Volatile organic compounds (VOCs) as environmental pollutants were associated with respiratory diseases. Pulmonary fibrosis (PF) was characterized by an increase of extracellular matrix, leading to deterioration of lung function. The adverse effects on lung and the potential mechanism underlying VOCs induced PF had not been elucidated clearly. In this study, the indoor VOCs exposure mouse model along with an ex vivo biosensor assay was established. Based on scRNA-seq analysis, the adverse effects on lung and potential molecular mechanism were studied. Herein, the results showed that VOCs exposure from indoor decoration contributed to decreased lung function and facilitated pulmonary fibrosis in mice. Then, the whole lung cell atlas after VOCs exposure and the heterogeneity of fibroblasts were revealed. We explored the molecular interactions among various pulmonary cells, suggesting that endothelial cells contributed to fibroblasts activation in response to VOCs exposure. Mechanistically, pulmonary microvascular endothelial cells (MPVECs) secreted Gas6 after VOCs-induced PANoptosis phenotype, bound to the Axl in fibroblasts, and then activated fibroblasts. Moreover, Atf3 as the key gene negatively regulated PANoptosis phenotype to ameliorate fibrosis induced by VOCs exposure. These novel findings provided a new perspective about MPVECs could serve as the initiating factor of PF induced by VOCs exposure.

Exposure to volatile organic compounds and mortality in US adults: A population-based prospective cohort study

Volatile organic compounds (VOCs) are ubiquitous in both indoor and outdoor environments. Evidence on the associations of individual and joint VOC exposure with all-cause and cause-specific mortality is limited. Measurements of 15 urinary VOC metabolites were available to estimate exposure to 12 VOCs in the National Health and Nutritional Examination Survey (NHANES) 2005-2006 and 2011-2018. The environment risk score (ERS) was calculated using LASSO regression to reflect joint exposure to VOCs. Follow-up data on death were obtained from the NHANES Public-Use Linked Mortality File through December 31, 2019. Cox proportional hazard models and restricted cubic spline models were applied to evaluate the associations of individual and joint VOC exposures with all-cause and cause-specific mortality. Population attributable fractions were calculated to assess the death burden attributable to VOC exposure. During a median follow-up of 6.17 years, 734 (8.34 %) deaths occurred among 8799 adults. Urinary metabolites of acrolein, acrylonitrile, 1,3-butadiene, and ethylbenzene/styrene were significantly associated with all-cause, cardiovascular disease (CVD), respiratory disease (RD), and cancer mortality in a linear dose-response manner. Linear and robust dose-response relationships were also observed between ERS and all-cause and cause-specific mortality. Each 1-unit increase in ERS was associated with a 33.6 %, 39.1 %, 109.8 %, and 67.8 % increase for all-cause, CVD, RD, and cancer mortality risk, respectively. Moreover, joint exposure to VOCs contributed to 17.95 % of all-cause deaths, 13.49 % of CVD deaths, 35.65 % of RD deaths, and 33.85 % of cancer deaths. Individual and joint exposure to VOCs may enhance the risk of all-cause and cause-specific mortality. Reducing exposure to VOCs may alleviate the all-cause and cause-specific death burden.

Urinary volatile organic compound metabolites and COPD among US adults: mixture, interaction and mediation analysis

BACKGROUND

Volatile organic compounds (VOCs) encompass hundreds of high production volume chemicals and have been reported to be associated with adverse respiratory outcomes such as chronic obstructive pulmonary disease (COPD). However, research on the combined toxic effects of exposure to various VOCs on COPD is lacking. We aimed to assess the effect of VOC metabolite mixture on COPD risk in a large population sample.

METHODS

We assessed the effect of VOC metabolite mixture on COPD risk in 5997 adults from the National Health and Nutrition Examination Survey (NHANES) from 2011 to 2020 (pre-pandemic) using multivariate logistic regression, Bayesian weighted quantile sum regression (BWQS), quantile-based g-Computation method (Qgcomp), and Bayesian kernel machine regression (BKMR). We explored whether these associations were mediated by white blood cell (WBC) count and total bilirubin.

RESULTS

In the logistic regression model, we observed a significantly increased risk of COPD associated with 9 VOC metabolites. Conversely, N-acetyl-S-(benzyl)-L-cysteine (BMA) and N-acetyl-S-(n-propyl)-L-cysteine (BPMA) showed insignificant negative correlations with COPD risk. The overall mixture exposure demonstrated a significant positive relationship with COPD in both the BWQS model (adjusted odds ratio (OR) = 1.30, 95% confidence interval (CI): 1.06, 1.58) and BKMR model, and with marginal significance in the Qgcomp model (adjusted OR = 1.22, 95% CI: 0.98, 1.52). All three models indicated a significant effect of the VOC metabolite mixture on COPD in non-current smokers. WBC count mediated 7.1% of the VOC mixture associated-COPD in non-current smokers.

CONCLUSIONS

Our findings provide novel evidence suggesting that VOCs may have adverse associations with COPD in the general population, with N, N- Dimethylformamide and 1,3-Butadiene contributing most. These findings underscore the significance of understanding the potential health risks associated with VOC mixture and emphasize the need for targeted interventions to mitigate the adverse effects on COPD risk.

Associations between ultrafine particle pollution and daily outpatient visits for respiratory diseases in Shanghai, China: a time-series analysis

Previous epidemiological studies have linked short-term exposure to particulate matter with outpatient visits for respiratory diseases. However, evidence on ultrafine particle (UFP) is still scarce in China. To investigate the association between short-term UFP exposure and outpatient visits for respiratory diseases as well as the corresponding lag patterns, information on outpatient visits for main respiratory diseases during January 1, 2017, to December 31, 2019 was collected from electronic medical records of two large tertiary hospitals in Shanghai, China. Generalized additive models employing a Quasi-Poisson distribution were employed to investigate the relationships between UFP and respiratory diseases. We computed the percentage change and its corresponding 95% confidence interval (CI) for outpatient visits related to respiratory diseases per interquartile range (IQR) increase in UFP concentrations. Based on a total of 1,034,394 hospital visits for respiratory diseases in Shanghai, China, we found that the strongest associations of total UFP with acute upper respiratory tract infection (AURTI), bronchitis, chronic obstructive pulmonary disease (COPD), and pneumonia occurred at lag 03, 03, 0, and 03 days, respectively. Each IQR increase in the total UFP concentrations was associated with increments of 9.02% (95% CI: 8.64-9.40%), 3.94% (95% CI: 2.84-5.06%), 4.10% (95% CI: 3.01-5.20%), and 10.15% (95% CI: 9.32-10.99%) for AURTI, bronchitis, COPD, and pneumonia, respectively. Almost linear concentration-response relationship curves without apparent thresholds were observed between total UFP and outpatient-department visits for four respiratory diseases. Stratified analyses illustrated significantly stronger associations of total UFP with AURTI, bronchitis, and pneumonia among female patients, while that with COPD was stronger among male patients. After adjustment of criteria air pollutants, these associations all remained robust. This time-series study indicates that short-term exposure to UFP was associated with increased risk of hospital visits for respiratory diseases, underscoring the importance of reducing ambient UFP concentrations for respiratory diseases control and prevention.

The neuroprotective effect of quercetin nanoparticles in the therapy of neuronal damage stimulated by acrolein

A gradual loss of neuronal function or structure causes neurodegenerative disorders such as Parkinson's and Alzheimer's. Neurological damage might cause cell death. Acrolein is a high-risk air and water contaminant that causes neurodegenerative disorders. Quercetin has several strategies for treating neurodegenerative disorders but has limited bioavailability inside the body. One of the hypotheses offered to improve quercetin's bioavailability is to convert it into quercetin nanoparticles. This study aims to comprehend the immunohistochemical devastation that might arise in the cerebellum because of acrolein treatment. Furthermore, the protective and ameliorative roles of quercetin nanoparticles against oxidative stress and neurotoxicity induced in mice by acrolein were assessed. Ninety male albino rats weighing 120 to 200 g were used in the present investigation. The animals were split up into the following six groups: the control group, the acrolein-treated group: animals were given acrolein (3 mg/kg) for 30 days, quercetin nanoparticles treated group: animals were given quercetin nanoparticles (30 mg/kg) for 30 days. The administration of acrolein was found to be connected to immunohistochemical abnormalities in the cerebellum. Marked differences were observed in Bax, Bcl-2, TNF-α, and GFAP expressions in the cerebellum. Treatment of rats with quercetin nanoparticles either before or after treatment with acrolein has been found to preserve the cerebellum tissues from the toxic impacts and oxidative stress induced by acrolein. This may open the door to more nanomedicine studies and a new avenue for employing nanoparticles as a therapeutic intervention in neurodegenerative illnesses.

Single-chemical and mixture effects of multiple volatile organic compounds exposure on liver injury and risk of non-alcoholic fatty liver disease in a representative general adult population

Evidence on liver injury and non-alcoholic fatty liver disease (NAFLD) from volatile organic compounds (VOCs) exposure is insufficient. A cross-sectional study including 3011 US adults from the National Health and Nutrition Examination Survey was conducted to explore the associations of urinary exposure biomarkers (EBs) for 13 VOCs (toluene, xylene, ethylbenzene, styrene, acrylamide, N,N-dimethylformamide, acrolein, crotonaldehyde, 1,3-butadiene, acrylonitrile, cyanide, propylene oxide, and 1-bromopropane) with liver injury biomarkers and the risk of NAFLD by performing single-chemical (survey weight regression) and mixture (Bayesian kernel machine regression [BKMR] and weighted quantile sum [WQS]) analyses. We found significant positive associations of EBs for toluene and 1-bromopropane with alanine aminotransferase (ALT), EBs for toluene, crotonaldehyde, and 1,3-butadiene with asparate aminotransferase (AST), EBs for 1,3-butadiene and cyanide with alkaline phosphatase (ALP), EBs for xylene and cyanide with hepamet fibrosis score (HFS), EBs for the total 13 VOCs (except propylene oxide) with United States fatty liver index (USFLI), and EBs for xylene, N,N-dimethylformamide, acrolein, crotonaldehyde, and acrylonitrile with NALFD; and significant inverse associations of EBs for ethylbenzene, styrene, acrylamide, acrolein, crotonaldehyde, 1,3-butadiene, acrylonitrile, cyanide, and propylene oxide with total bilirubin, EBs for ethylbenzene, styrene, acrylamide, acrolein, 1,3-butadiene, acrylonitrile, and cyanide with albumin (ALB), EBs for ethylbenzene, styrene, acrylamide, N,N-dimethylformamide, acrolein, crotonaldehyde, 1,3-butadiene, acrylonitrile, cyanide, and propylene oxide with total protein (TP), and EB for 1-bromopropane with AST/ALT (all P-FDR<0.05). In BKMR and WQS, the mixture of VOC-EBs was significantly positively associated with ALT, AST, ALP, HFS, USFLI, and the risk of NAFLD, while significantly inversely associated with TBIL, ALB, TP, and AST/ALT. VOCs exposure was associated with liver injury and increased risk of NAFLD in US adults. These findings highlight that great attention should be paid to the potential risk of liver health damage from VOCs exposure.

Carbon disulfide exposure induced lung function reduction partly through oxidative protein damage: A cross-sectional and longitudinal analysis

Carbon disulfide (CS₂) exposure has been associated with lung function reduction in occupational population. However, evidence on the general population with relatively low CS₂ exposure is lacking and the mechanism involved remains largely unknown. Urinary CS₂ metabolite (2-mercaptothiazolidine-4-carboxylic acid, TTCA) and lung function were determined in the urban adults from the Wuhan-Zhuhai cohort at baseline in 2011-2012 and were repeated every 3 years. Cross-sectional and longitudinal associations between TTCA and lung function were estimated using linear mixed models. Inflammation and oxidative damage biomarkers in blood/urine were measured to evaluate their potential mediating roles involved. Cross-sectionally, participants in the highest quartile of TTCA level showed a 0.64% reduction in FEV₁/FVC and a -308.22 mL/s reduction in PEF, compared to those in the lowest quartile. Longitudinally, participants with consistently high TTCA level had annually -90.27 mL/s decline in PEF, compared to those with consistently low TTCA level. Mediation analysis revealed that plasma protein carbonyl mediated 49.89% and 22.10% of TTCA-associated FEV₁/FVC and PEF reductions, respectively. Conclusively, there was a cross-sectional and longitudinal association between CS₂ exposure and lung function reduction in the general urban adults, and protein carbonylation (oxidative protein damage) partly mediated lung function reduction from CS₂ exposure.

The potential role of plasma miR-4301 in PM2.5 exposure-associated lung function reduction

The effect of PM_2.5 exposure on lung function reduction has been well-documented, but the underlying mechanism remains unclear. MiR-4301 may be involved in regulating pathways related to lung injury/repairment, and this study aimed to explore the potential role of miR-4301 in PM_2.5 exposure-associated lung function reduction. A total of 167 Wuhan community nonsmokers were included in this study. Lung function was measured and personal PM_2.5 exposure moving averages were evaluated for each participant. Plasma miRNA was determined by real-time polymerase chain reaction. A generalized linear model was conducted to assess the relationships among personal PM_2.5 moving average concentrations, lung function, and plasma miRNA. The mediation effect of miRNA on the association of personal PM_2.5 exposure with lung function reduction was estimated. Finally, we performed pathway enrichment analysis to predict the underlying pathways of miRNA in lung function reduction from PM_2.5 exposure. We found that each 10 μg/m³ increase in the 7-day personal PM_2.5 moving average concentration (Lag0-7) was related to a 46.71 mL, 1.15%, 157.06 mL/s, and 188.13 mL/s reductions in FEV₁, FEV₁/FVC, PEF, and MMF, respectively. PM_2.5 exposure was negatively associated with plasma miR-4301 expression levels in a dose‒response manner. Additionally, each 1% increase in miR-4301 expression level was significantly associated with a 0.36 mL, 0.01%, 1.14 mL/s, and 1.28 mL/s increases in FEV₁, FEV₁/FVC, MMF, and PEF, respectively. Mediation analysis further revealed that decreased miR-4301 mediated 15.6% and 16.8% of PM_2.5 exposure-associated reductions in FEV₁/FVC and MMF, respectively. Pathway enrichment analyses suggested that the wingless related-integration site (Wnt) signaling pathway might be one of the pathways regulated by miR-4301 in the reduction of lung function from PM_2.5 exposure. In brief, personal PM_2.5 exposure was negatively associated with plasma miR-4301 or lung function in a dose‒response manner. Moreover, miR-4301 partially mediated the lung function reduction associated with PM_2.5 exposure.

Long-term effect of styrene and ethylbenzene exposure on fasting plasma glucose: A gene-environment interaction study

Styrene and ethylbenzene (S/EB) are hazardous pollutants that have attracted worldwide concern. In this prospective cohort study, S/EB exposure biomarker (the sum of mandelic acid and phenylglyoxylic acid [MA+PGA]) and fasting plasma glucose (FPG) were repeatedly measured three times. The polygenic risk score (PRS) based on 137 single nucleotide polymorphisms for type 2 diabetes mellitus (T2DM) was calculated to evaluate cumulative genetic effect. In repeated-measures cross-sectional analyses, MA+PGA (β [95% confidence interval]: 0.106 [0.022, 0.189]) and PRS (0.111 [0.047, 0.176]) were significantly related to FPG. For long-term effect assessment, participants with sustained high MA+PGA or with high PRS had 0.021 (95% CI: -0.398, 0.441) or 0.465 (0.064, 0.866) mmol/L increase in FPG, respectively, over 3 years follow-up, and had 0.256 (0.017, 0.494) or 0.265 (0.004, 0.527) mmol/L increase in FPG, respectively, over 6 years follow-up. We further detected a significant interaction effect between MA+PGA and PRS on FPG change, compared with participants with sustained low MA+PGA and low PRS, those with sustained high MA+PGA and high PRS had 0.778 (0.319, 1.258) mmol/L increase in FPG (P for interaction=0.028) over 6 years follow-up. Our study provides the first evidence that long-term exposure to S/EB potentially increases FPG, which might be aggravated by genetic susceptibility.

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.

Lipid peroxidation mediates the association between iron overload and liver injury: cross-sectional and longitudinal analyses in general Chinese urban adults

Iron overload has been associated with acute/chronic organ failure, but whether iron overload induces liver injury remains unclear. The objectives of this study were to assess the relationship between urinary iron and serum alanine aminotransferase (ALT, a biomarker for liver injury), and investigate the potential mediating roles of lipid peroxidation and oxidative DNA damage in such association. Levels of urinary iron, serum ALT, and urinary biomarkers of lipid peroxidation (8-iso-prostaglandin-F_2α [8-iso-PGF_2α]) and oxidative DNA damage (8-hydroxy-deoxyguano-sine [8-OHdG]) were measured among 5386 observations of 4220 participants from the Wuhan-Zhuhai cohort. The relationships of urinary iron with serum ALT and risk of hyperALT were evaluated by linear mixed model and logistic regression model, respectively. The mediating roles of 8-iso-PGF_2α and 8-OHdG were assessed by mediation analyses. This cross-sectional analysis found that urinary iron was positively associated with ALT (β = 0.032; 95% CI: 0.020, 0.044) and hyperALT prevalence (OR = 1.127; 95% CI: 1.065, 1.192). After 3 years of follow-up, participants with persistent high iron levels had increased risk of developing hyperALT (RR = 3.800; 95% CI: 1.464, 9.972) when compared with those with persistent low iron levels. In addition, each 1% increase in urinary iron was associated with a 0.146% (95% CI: 0.128%, 0.164%) increase and a 0.192% (95% CI: 0.154%, 0.229%) increase in 8-iso-PGF_2α and 8-OHdG, respectively. Urinary 8-iso-PGF_2α (β = 0.056; 95% CI: 0.039, 0.074) was positively associated with ALT, while the association between 8-OHdG and ALT was insignificant. Furthermore, increased 8-iso-PGF_2α significantly mediated 22.48% of the urinary iron-associated ALT increment. Our study demonstrated that iron overload was significantly associated with liver injury, which was partly mediated by lipid peroxidation. Controlling iron intake and regulating lipid peroxidation may help in preventing liver injury.

Low-Grade Inflammation and Ultra-Processed Foods Consumption: A Review

Low-grade inflammation alters the homeostasis of the organism and favors the onset of many chronic diseases. The global growth in the prevalence of noncommunicable diseases in recent years has been accompanied by an increase in the consumption of ultra-processed foods (UPF). Known to be hyperpalatable, economic and ready-to-eat, increased consumption of UPF has already been recognized as a risk factor for several chronic diseases. Different research groups have tried to investigate whether UPF consumption could promote low-grade inflammation and thus favor the development of noncommunicable diseases. Current evidence highlights the adverse health effects of UPF characteristics, not only due to the nutrients provided by a diet rich in UPF, but also due to the non-nutritive components present in UPF and the effect they may have on gut health. This review aims to summarize the available evidence on the possible relationship between excessive UPF consumption and modulation of low-grade inflammation, as potential promoters of chronic disease.

The Tobacco Smoke Component, Acrolein, as a Major Culprit in Lung Diseases and Respiratory Cancers: Molecular Mechanisms of Acrolein Cytotoxic Activity

Acrolein, a highly reactive unsaturated aldehyde, is a ubiquitous environmental pollutant that seriously threatens human health and life. Due to its high reactivity, cytotoxicity and genotoxicity, acrolein is involved in the development of several diseases, including multiple sclerosis, neurodegenerative diseases such as Alzheimer’s disease, cardiovascular and respiratory diseases, diabetes mellitus and even the development of cancer. Traditional tobacco smokers and e-cigarette users are particularly exposed to the harmful effects of acrolein. High concentrations of acrolein have been found in both mainstream and side-stream tobacco smoke. Acrolein is considered one of cigarette smoke’s most toxic and harmful components. Chronic exposure to acrolein through cigarette smoke has been linked to the development of asthma, acute lung injury, chronic obstructive pulmonary disease (COPD) and even respiratory cancers. This review addresses the current state of knowledge on the pathological molecular mechanisms of acrolein in the induction, course and development of lung diseases and cancers in smokers.

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.

Cross-sectional and longitudinal relationships between urinary 1-bromopropane metabolite and pulmonary function and underlying role of oxidative damage among urban adults in the Wuhan-Zhuhai cohort in China

1-bromopropane is a US Environmental Protection Agency-identified significant hazardous air pollutant with concerned adverse respiratory effect. We aimed to investigate the relationship between 1-bromopropane exposure and pulmonary function and the underlying role of oxidative damage, which all remain unknown. Pulmonary function and urinary biomarkers of 1-bromopropane exposure (N-Acetyl-S-(n-propyl)-L-cysteine, BPMA) and oxidative damage to DNA (8-hydroxy-deoxyguanosine, 8-OHdG) and lipid (8-iso-prostaglandin-F2α, 8-iso-PGF2α) were measured for 3259 Chinese urban adults from the Wuhan-Zhuhai cohort. The cross-sectional relationship of BPMA with pulmonary function and the joint relationship of BPMA and 8-OHdG or 8-iso-PGF2α with pulmonary function were investigated by linear mixed models. The mediating roles of 8-OHdG and 8-iso-PGF2α were evaluated by mediation analysis. Additionally, a panel of 138 subjects was randomly convened from the same cohort to evaluate the stability of BPMA repeatedly measured in urine samples collected over consecutive three days and intervals of one, two, and three years, and to estimate the longitudinal relationship of BPMA with pulmonary function change in three years. We found each 3-fold increase in BPMA was cross-sectionally related to FVC and FEV₁ reductions by 29.88-mL and 25.67-mL, respectively (all P < 0.05). Joint relationship of BPMA and 8-OHdG rather than 8-iso-PGF2α with reduced pulmonary function was observed. Moreover, 8-OHdG significantly mediated 9.44% of the BPMA-related FVC reduction. Findings from the panel revealed a fair to excellent stability (intraclass correlation coefficient: 0.43-0.79) of BPMA in repeated urines collected over a period of three years. Besides, BPMA was longitudinally related to pulmonary function reduction in three years: compared with subjects with persistently low BPMA level, those with persistently high BPMA level had 79.08-mL/year and 49.80-mL/year declines in FVC and FEV₁, respectively (all P < 0.05). Conclusively, 1-bromopropane exposure might impair pulmonary function of urban adult population, and oxidative DNA damage might be a potential mechanism underlying 1-bromopropane impairing pulmonary function especially FVC.