Pathophysiology of tobacco smoke exposure: recent insights from comparative and redox proteomics

Assessing the predictive value of smoking history for immunotherapy outcomes in bladder cancer patients

Background

The therapeutic effectiveness of immune checkpoint inhibitors (ICIs) in bladder cancer varies among individuals. Identifying reliable predictors of response to these therapies is crucial for optimizing patient outcomes.

Methods

This retrospective study analyzed 348 bladder cancer patients treated with ICIs, with additional validation using data from 248 patients at our institution who underwent PD-L1 immunohistochemical staining. We examined patient smoking history, clinicopathological characteristics, and immune phenotypes. The main focus was the correlation between smoking history and immunotherapy outcomes. Multivariate logistic and Cox proportional hazard regressions were used to adjust for confounders.

Results

The study cohort comprised 348 bladder cancer patients receiving ICIs. Among them, 116 (33.3%) were never smokers, 197 (56.6%) were former smokers (median pack-years = 28), and 35 (10.1%) were current smokers (median pack-years = 40). Analysis revealed no statistically significant difference in overall survival across different smoking statuses (objective response rates were 11.4% for current smokers, 17.2% for never smokers, and 22.3% for former smokers; P = 0.142, 0.410, and 0.281, respectively). However, a notable trend indicated a potentially better response to immunotherapy in former smokers compared to current and never smokers. In the validation cohort of 248 patients from our institution, immunohistochemical analysis showed that PD-L1 expression was significantly higher in former smokers (55%) compared to current smokers (37%) and never smokers (47%). This observation underscores the potential influence of smoking history on the tumor microenvironment and its responsiveness to ICIs.

Conclusion

In conclusion, our study demonstrates the importance of incorporating smoking history in predicting the response to immunotherapy in bladder cancer patients, highlighting its role in personalized cancer treatment approaches. Further research is suggested to explore the comprehensive impact of lifestyle factors on treatment outcomes.

Association between passive smoking and the risk of rheumatoid arthritis: a systematic review and meta-analysis

In order to provide a basis for the prevention of RA, this systematic review and meta-analysis evaluated the association between passive smoking and the risk of developing RA. We searched electronic databases, including PubMed, Cochrane Central Register of Controlled Trials, Web of Science, and Embase, for published literature from the establishment to March 2022. Then we included subject-related cohort studies and case-control studies, and two researchers independently screened and extracted relevant data. Finally, we performed a meta-analysis, cumulative meta-analysis, and dose-response meta-analysis using the Stata software and evaluated the included literature for the level of evidence. This meta-analysis included three case-control and three cohort studies. There was only a small amount of statistical heterogeneity among the studies (I² = 34.9%). According to the study results, the risk of RA was 12% higher in passive smokers than in unexposed individuals. In subgroup analysis, a 12% increase in the prevalence of RA was observed in those exposed to passive smoking in adulthood. The developing RA rate was 34% higher in individuals exposed to passive smoking during childhood than in unexposed individuals. As time progressed and with the inclusion of extensive sample studies in the cumulative meta-analysis, the precision of the overall incidence effect values gradually increased. A dose-response meta-analysis showed no statistical significance that the risk of RA increased with the number of passive smoking years. Passive smoking may relate to the risk of RA, especially in childhood exposures.

Pre-conceptional and prenatal exposure to secondhand smoke and autism spectrum disorder: a national multi-center study in China

BACKGROUND

Despite extensive research evaluating the association between prenatal exposure to secondhand smoke (SHS) and the development of autism spectrum disorders (ASD), no study has investigated the association by considering the pre-conceptional period. This study aimed to investigate the associations of pre-conceptional and prenatal SHS exposure and the development of ASD among toddlers.

METHODS

In this cross-sectional study, parents of 6049 toddlers aged 16-30 months were recruited from 7 tertiary hospitals, 21 communities, and 7 kindergartens located in seven cities in six provinces from five geographical regions of China. We analyzed the associations of SHS exposure and the odds of ASD among toddlers in different exposure windows (pre-conceptional and/or prenatal periods). Data were analyzed from November 2021 to January 2022.

RESULTS

Among the 6049 toddlers included in the analysis [22.7 (4.1) months; 44.8% girls], 71 were identified and diagnosed with ASD. Compared with the unexposed toddlers, toddlers with pre-conceptional SHS exposure had higher odds of ASD (OR 2.30, 95% CI 1.36-3.84), while we observed a non-significantly positive association regarding prenatal SHS exposure. When considering both pre-conceptional and prenatal periods, toddlers who were continuously exposed to SHS during these two periods had higher odds than those without SHS exposure (OR 2.32, 95% CI 1.24-4.14).

CONCLUSION

We reported positive SHS-ASD associations when exposed during the pre-conceptional period and continuously exposed during pre-conceptional and prenatal periods, emphasizing the critical window of pre-conception for targeted intervention on smoking.

IL-18 Gene rs187238 and rs1946518 Polymorphisms and Expression in Gingival Tissue in Patients with Periodontitis

Periodontitis is a chronic disease with disturbed balance between the immune and inflammatory response of the host to bacteria. Many studies have shown that proinflammatory cytokines play a significant role in the pathogenesis of periodontal disease. In this study, we examined the association between the IL-18 gene rs187238 and rs1946518 polymorphisms and periodontitis in non-smoking and smoking patients. This study enrolled 200 patients with periodontitis (130 non-smokers and 70 smokers) and 156 control subjects (124 non-smokers and 32 smokers). There were no statistically significant differences in the distribution of the rs187238 and rs1946518 IL-18 genotypes and alleles between patients with periodontitis and control subjects, between smoking patients with periodontitis and smoking control subjects, and between non-smoking patients with periodontitis and non-smoking control subjects. There were no statistically significant differences in clinical parameters in relation to the IL18 rs187238 genotypes. In patients with the IL18 rs1946518 GG genotype, we observed increased values of bleeding on probing (BoP) and periodontal probing depth (PPD), compared to subjects with the TT genotype. In patients with periodontitis, we observed statistically significant decreased expression of the IL-18 gene in comparison with healthy subjects (0.231 ± 0.163 vs. 0.663 ± 0.197, p = 0.0008). In addition, the IL-18 gene expression in gingival tissue in patients with periodontitis correlated positively with the number of remaining teeth. The results of our study suggest that the IL-18 rs187238 and rs1946518 polymorphisms are not significant risk indicators of periodontitis in our population. However, in patients with the IL18 rs1946518 GG genotype, we observed increased values of BoP and PPD, compared to subjects with the TT genotype. In addition, in gingival tissue of patients with periodontitis, we have detected decreased expression of IL-18. The gingival expression of IL-18 in patients with periodontitis correlated positively with number of remaining teeth. The above results suggest that IL-18, in addition to its pro-inflammatory effects in periodontal disease, may also exhibit protective properties.

The Impact of Tobacco Cigarettes, Vaping Products and Tobacco Heating Products on Oxidative Stress

Cells constantly produce oxidizing species because of their metabolic activity, which is counteracted by the continuous production of antioxidant species to maintain the homeostasis of the redox balance. A deviation from the metabolic steady state leads to a condition of oxidative stress. The source of oxidative species can be endogenous or exogenous. A major exogenous source of these species is tobacco smoking. Oxidative damage can be induced in cells by chemical species contained in smoke through the generation of pro-inflammatory compounds and the modulation of intracellular pro-inflammatory pathways, resulting in a pathological condition. Cessation of smoking reduces the morbidity and mortality associated with cigarette use. Next-generation products (NGPs), as alternatives to combustible cigarettes, such as electronic cigarettes (e-cig) and tobacco heating products (THPs), have been proposed as a harm reduction strategy to reduce the deleterious impacts of cigarette smoking. In this review, we examine the impact of tobacco smoke and MRPs on oxidative stress in different pathologies, including respiratory and cardiovascular diseases and tumors. The impact of tobacco cigarette smoke on oxidative stress signaling in human health is well established, whereas the safety profile of MRPs seems to be higher than tobacco cigarettes, but further, well-conceived, studies are needed to better understand the oxidative effects of these products with long-term exposure.

Smoking induces sex-specific changes in the small airway proteome

Introduction

Cigarette smoke triggers many cellular and signaling responses in the lung and the resulting inflammation plays a central role in smoke-related lung diseases, such as COPD. We explored the effects of smoking on the small airway proteome in samples obtained by collection of exhaled particles with the aim to identify specific proteins dysregulated by smoking.

Methods

Exhaled particles were obtained from 38 current smokers, 47 former smokers and 22 healthy controls with the PExA method. 120 ng of sample was collected from individual subjects and analyzed with the SOMAscan proteomics platform. General linear model-based statistics were performed.

Results

Two hundred and three proteins were detected in at least half of 107 total samples. Active smoking exerted a significant impact on the protein composition of respiratory tract lining fluid (RTLF), with 81 proteins altered in current smokers compared to never smokers (p < 0.05, q < 0.124). Among the proteins most clearly discriminating between current and never smokers were sRAGE, FSTL3, SPOCK2 and protein S, all of them being less abundant in current smokers. Analysis stratified for sex unveiled sex differences with more pronounced proteomic alterations due to active smoking in females than males. Proteins whose abundance was altered by active smoking in women were to a larger extent related to the complement system. The small airway protein profile of former smokers appeared to be more similar to that observed in never smokers.

Conclusions

The study shows that smoking has a strong impact on protein expression in the small airways, and that smoking affects men and women differently, suggesting PExA sampling combined with high sensitivity protein analysis offers a promising platform for early detection of COPD and identification of novel COPD drug targets.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12931-021-01825-6.

Perinatal exposure to nicotine alters spermatozoal DNA methylation near genes controlling nicotine action

Perinatal smoke/nicotine exposure alters lung development and causes asthma in exposed offspring, transmitted transgenerationally. The mechanism underlying the transgenerational inheritance of perinatal smoke/nicotine-induced asthma remains unknown, but germline epigenetic modulations may play a role. Using a well-established rat model of perinatal nicotine-induced asthma, we determined the DNA methylation pattern of spermatozoa of F1 rats exposed perinatally to nicotine in F0 gestation. To identify differentially methylated regions (DMRs), reduced representation bisulfite sequencing was performed on spermatozoa of F1 litters. The top regulated gene body and promoter DMRs were tested for lung gene expression levels, and key proteins involved in lung development and repair were determined. The overall CpG methylation in F1 sperms across gene bodies, promoters, 5'-UTRs, exons, introns, and 3'-UTRs was not affected by nicotine exposure. However, the methylation levels were different between the different genomic regions. Eighty one CpG sites, 16 gene bodies, and 3 promoter regions were differentially methylated. Gene enrichment analysis of DMRs revealed pathways involved in oxidative stress, nicotine response, alveolar and brain development, and cellular signaling. Among the DMRs, Dio1 and Nmu were the most hypermethylated and hypomethylated genes, respectively. Gene expression analysis showed that the mRNA expression and DNA methylation were incongruous. Key proteins involved in lung development and repair were significantly different (FDR < 0.05) between the nicotine and placebo-treated groups. Our data show that DNA methylation is remodeled in offspring spermatozoa upon perinatal nicotine exposure. These epigenetic alterations may play a role in transgenerational inheritance of perinatal smoke/nicotine induced asthma.

Antioxidants in smokers

Cigarette smoke (CS) is likely the most common preventable cause of human morbidity and mortality worldwide. Consequently, inexpensive interventional strategies for preventing CS-related diseases would positively impact health systems. Inhaled CS is a powerful inflammatory stimulus and produces a shift in the normal balance between antioxidants and oxidants, inducing oxidative stress in both the respiratory system and throughout the body. This enduring and systemic pro-oxidative state within the body is reflected by increased levels of oxidative stress and inflammation biomarkers seen in smokers. Smokers might benefit from consuming antioxidant supplements, or a diet rich in fruit and vegetables, which can reduce the CS-related oxidative stress. This review provides an overview of the plasma profile of antioxidants observable in smokers and examines the heterogeneous literature to elucidate and discuss the effectiveness of interventional strategies based on antioxidant supplements or an antioxidant-rich diet to improve the health of smokers. An antioxidant-rich diet can provide an easy-to-implement and cost-effective preventative strategy to reduce the risk of CS-related diseases, thus being one of the simplest ways for smokers to stay in good health for as long as possible. The health benefits attributable to the intake of antioxidants have been observed predominantly when these have been consumed within their natural food matrices in an optimal antioxidant-rich diet, while these preventive effects are rarely achieved with the intake of individual antioxidants, even at high doses.

Impact of Smoking Cessation on Periodontal Tissues

There is cumulative evidence supporting the negative effects of smoking on periodontal tissues. Smoking cessation can be successfully accomplished through specific programs, including behaviour modification and medications, and has been suggested as a suitable way to reduce the risk of several diseases, including periodontitis. The aim of this review is to provide a concise overview of the current knowledge about the impact of smoking cessation on periodontal tissues and therapy, with data from studies published in the last 15 years. Literature was searched using Medline database from 2005 up to and including September 2020 using medical subject heading (MeSH) terms and other search terms, restricted to the English language. Studies were evaluated and summarised in a narrative review format. Results demonstrated that there is convincing evidence to support the benefits of tobacco cessation in reducing the risk of periodontitis and tooth loss. In addition, the harmful effects of smoking on periodontal tissues seem to be assuaged as the number of years since quitting increases. The existing current evidence, even limited, also shows that smoking cessation may result in additional benefits to the outcome of nonsurgical periodontal treatment. Periodontal care providers should not only check their patient's smoking habit for estimating risk of disease progression and predictability of periodontal therapy, but they should also help smokers improve their oral and systemic health by providing efficient and personalised tobacco‐cessation counselling and treatment.

Smoking status and endothelial function in Japanese men

It is established that smoking is a major risk factor of atherosclerosis. Endothelial dysfunction occurs in the initial step in the pathogenesis of atherosclerosis and plays a critical role in the development of atherosclerosis. The purpose of this study was to evaluate the association between smoking status and endothelial function in detail in men. We measured flow-mediated vasodilation (FMD) in 2209 Japanese men including 1181 men who had never smoked and 1028 current smokers. All of the participants were divided into five groups by smoking pack-years: never smoker group (= 0), light smoker group (> 0 to 10), moderate smoker group (> 10 to 20), heavy smoker group (> 20 to 30) and excessive smoker group (> 30). FMD significantly decreased in relation to pack-years (6.6 ± 3.4% in the never smoker group, 6.8 ± 3.0% in the light smoker group, 6.5 ± 2.9% in the moderate smoker group, 5.9 ± 2.9% in the heavy smoker group, and 4.9 ± 2.7% in the excessive smoker group; P < 0.001). After adjustment for age (≥ 65 years), body mass index, systolic blood pressure, low-density lipoprotein cholesterol, glucose, and year of recruitment, FMD was significantly smaller in the excessive smoker group than in the never smoker group as a reference group (OR 1.95, 95% CI 1.42 to 2.67; P < 0.001). These findings suggest that FMD decreases with an increase in the number of cigarettes smoked and that excessive smoking is associated with endothelial dysfunction. Cigarette smoking is harmful to vascular function in men who are heavy smokers.

Cellular and Molecular Mechanisms of Environmental Pollutants on Hematopoiesis

Hematopoiesis is a complex and intricate process that aims to replenish blood components in a constant fashion. It is orchestrated mostly by hematopoietic progenitor cells (hematopoietic stem cells (HSCs)) that are capable of self-renewal and differentiation. These cells can originate other cell subtypes that are responsible for maintaining vital functions, mediate innate and adaptive immune responses, provide tissues with oxygen, and control coagulation. Hematopoiesis in adults takes place in the bone marrow, which is endowed with an extensive vasculature conferring an intense flow of cells. A myriad of cell subtypes can be found in the bone marrow at different levels of activation, being also under constant action of an extensive amount of diverse chemical mediators and enzymatic systems. Bone marrow platelets, mature erythrocytes and leukocytes are delivered into the bloodstream readily available to meet body demands. Leukocytes circulate and reach different tissues, returning or not returning to the bloodstream. Senescent leukocytes, specially granulocytes, return to the bone marrow to be phagocytized by macrophages, restarting granulopoiesis. The constant high production and delivery of cells into the bloodstream, alongside the fact that blood cells can also circulate between tissues, makes the hematopoietic system a prime target for toxic agents to act upon, making the understanding of the bone marrow microenvironment vital for both toxicological sciences and risk assessment. Environmental and occupational pollutants, therapeutic molecules, drugs of abuse, and even nutritional status can directly affect progenitor cells at their differentiation and maturation stages, altering behavior and function of blood compounds and resulting in impaired immune responses, anemias, leukemias, and blood coagulation disturbances. This review aims to describe the most recently investigated molecular and cellular toxicity mechanisms of current major environmental pollutants on hematopoiesis in the bone marrow.

Cigarette smoke and glutathione: Focus on in vitro cell models

Cigarette smoke (CS) is one of the most important preventable risk factors for the development of respiratory diseases, cardiovascular diseases, stroke, and various types of cancer. Due to its high intracellular concentration and central role in maintaining the cellular redox state, glutathione (GSH) is one of the key players in several enzymatic and non-enzymatic reactions necessary for protecting cells against CS-induced oxidative stress. A plethora of in vitro cell models have been used over the years to assess the effects of CS on intracellular GSH and its disulphide forms, i.e. glutathione disulphide (GSSG) and S-glutathionylated proteins. In this review, we described the effects of cell exposure to CS on cellular GSH and formation of its oxidized forms and adducts (GSH-conjugates). We also discussed the limitations and relevance of in vitro cell models of exposure to CS and critically assessed the congruence between smokers and in vitro cell models. What emerges clearly is that results obtained in vitro should be interpreted with extreme caution, bearing in mind the limitations of the specific cell model used. Despite this, in vitro cell models remain important tools in the assessment of CS-induced oxidative damage.

Overexpression of HIF-1α and Morphological Alterations in the Tongue of Rats Exposed To Secondhand Smoke

Smoking is a risk factor for serious health problems and is associated with several changes in the tissues of the oral cavity. The aim of this study was to evaluate the collagen percentage, mast cells density, intensity of immunolabeled cells by anti-HIF-1α in the musculature lingual of rats exposed to secondhand smoke. Twenty-seven female Wistar albino rats were divided into three groups: rats not exposed to tobacco smoke inhalation (Control group) (n=7); rats exposed to smoke inhalation for 30 days (TAB 30) (n=10); and rats exposed to smoke inhalation for 45 days (TAB 45) (n=10). Subsequently, the animals were submitted to euthanasia and removal of the tongue for histological and immunohistochemistry processing and analysis. In the groups TAB 30 and TAB 45 there were a lower percentage of collagen, a higher density of mast cells and a greater intensity of anti-HIF-1α immunolabeled cells compared to Control group. There was also a positive and significant correlation between the percentage of collagen and mast cell density. There was not significative difference between TAB 30 e TAB 45 in any of the parameters evaluated. Therefore, the exposure of rats to secondhand smoke for 45 days causes decrease in perimysial collagen fibers, increase in the number of mast cells and increase in the immunolabeling for HIF-1α in lingual muscle cells. The present study was the first to evaluate the percentage of collagen, mast cell density and immunostaining for HIF-1α in rat tongues exposed to tobacco smoke.

Role of extracellular vesicles in cell-cell communication and inflammation following exposure to pulmonary toxicants

Extracellular vesicles (EVs) have emerged as key regulators of cell-cell communication during inflammatory responses to lung injury induced by diverse pulmonary toxicants including cigarette smoke, air pollutants, hyperoxia, acids, and endotoxin. Many lung cell types, including epithelial cells and endothelial cells, as well as infiltrating macrophages generate EVs. EVs appear to function by transporting cargo to recipient cells that, in most instances, promote their inflammatory activity. Biologically active cargo transported by EVs include miRNAs, cytokines/chemokines, damage-associated molecular patterns (DAMPs), tissue factor (TF)s, and caspases. Findings that EVs are taken up by target cells such as macrophages, and that this leads to increased proinflammatory functioning provide support for their role in the development of pathologies associated with toxicant exposure. Understanding the nature of EVs responding to toxic exposures and their cargo may lead to the development of novel therapeutic approaches to mitigating lung injury.

Cigarette Smoke Exposure Induces Retrograde Trafficking of CFTR to the Endoplasmic Reticulum

Chronic obstructive pulmonary disease (COPD), which is most commonly caused by cigarette smoke (CS) exposure, is the third leading cause of death worldwide. The cystic fibrosis transmembrane conductance regulator (CFTR) is an apical membrane anion channel that is widely expressed in epithelia throughout the body. In the airways, CFTR plays an important role in fluid homeostasis and helps flush mucus and inhaled pathogens/toxicants out of the lung. Inhibition of CFTR leads to mucus stasis and severe airway disease. CS exposure also inhibits CFTR, leading to the decreased anion secretion/hydration seen in COPD patients. However, the underlying mechanism is poorly understood. Here, we report that CS causes CFTR to be internalized in a clathrin/dynamin-dependent fashion. This internalization is followed by retrograde trafficking of CFTR to the endoplasmic reticulum. Although this internalization pathway has been described for bacterial toxins and cargo machinery, it has never been reported for mammalian ion channels. Furthermore, the rapid internalization of CFTR is dependent on CFTR dephosphorylation by calcineurin, a protein phosphatase that is upregulated by CS. These results provide new insights into the mechanism of CFTR internalization, and may help in the development of new therapies for CFTR correction and lung rehydration in patients with debilitating airway diseases such as COPD.

Protein carbonylation in human bronchial epithelial cells exposed to cigarette smoke extract

Cigarette smoke is a well-established exogenous risk factor containing toxic reactive molecules able to induce oxidative stress, which in turn contributes to smoking-related diseases, including cardiovascular, pulmonary, and oral cavity diseases. We investigated the effects of cigarette smoke extract on human bronchial epithelial cells. Cells were exposed to various concentrations (2.5-5-10-20%) of cigarette smoke extract for 1, 3, and 24 h. Carbonylation was assessed by 2,4-dinitrophenylhydrazine using both immunocytochemical and Western immunoblotting assays. Cigarette smoke induced increasing protein carbonylation in a concentration-dependent manner. The main carbonylated proteins were identified by means of two-dimensional electrophoresis coupled to MALDI-TOF mass spectrometry analysis and database search (redox proteomics). We demonstrated that exposure of bronchial cells to cigarette smoke extract induces carbonylation of a large number of proteins distributed throughout the cell. Proteins undergoing carbonylation are involved in primary metabolic processes, such as protein and lipid metabolism and metabolite and energy production as well as in fundamental cellular processes, such as cell cycle and chromosome segregation, thus confirming that reactive carbonyl species contained in cigarette smoke markedly alter cell homeostasis and functions.

Andrographolide antagonizes the cigarette smoke-induced epithelial-mesenchymal transition and pulmonary dysfunction through anti-inflammatory inhibiting HOTAIR

In cells of the lung surface, cigarette smoke (CS) induces inflammatory and epithelial-mesenchymal transition (EMT), effects that are related to pulmonary dysfunction and Chronic obstructive pulmonary disease (COPD). However, the molecular mechanisms involved remain largely unknown, and potential therapeutic approaches are under development. In the present study, with cell culture and animal studies, we showed that CS exposure causes pulmonary dysfunction and airway remodeling with inflammatory cell infiltration. Consistent with these pulmonary lesions, the inflammatory factors interleukin-6 (IL-6) and interleukin-8 (IL-8) were increased in mice exposed to CS for 4 days. Accordingly, downstream signal transducer and activator of transcription 3 (STAT3) was activated, which up-regulated expression of the lncRNA HOTAIR, and enhancer of zeste homolog 2 (EZH2). In addition, CS exposure led to decreased levels of E-cadherin and to increased N-cadherin, vimentin, and α-SMA, indicating that the EMT was induced in mouse lung tissues. These effects, including increases of IL-6 and HOTAIR, were confirmed in human bronchial epithelial (HBE) cells treated with cigarette smoke extract (CSE). Finally, we established that, in HBE cells, andrographolide reversed the CSE-induced EMT via decreasing IL-6 levels and, in an animal model, prevented CS-induced lung inflammation and small airway remodeling, indicating that it has potential clinical application for CS-induced pulmonary dysfunction and COPD.

Dissecting the molecular effects of cigarette smoke on proteasome function

Proteasome dysfunction is emerging as a novel pathomechanism for the development of chronic obstructive pulmonary disease (COPD), a major leading cause of death in the world. Cigarette smoke, one of the main risk factors for COPD, impairs proteasome function in vitro and in vivo. In the present study, we dissected the molecular changes induced by cigarette smoke on the proteasome in lung epithelial cells and mouse lungs. 26S proteasome pull-down, MS interactome, and stoichiometry analyses indicated that 26S proteasome complexes become instable in cigarette smoke-treated lung epithelial cells as well as in lungs of mice after three day smoke exposure. The interactome of the 26S was clearly altered in mouse lungs upon smoke exposure but not in cells after 24 h of smoke exposure. Using native MS analysis of purified 20S proteasomes, we observed some destabilization of 20S complexes purified from cigarette smoke-exposed cells in the absence of any dominant and inhibitory modification of proteasomal proteins. Taken together, our results suggest that cigarette smoke induces minor but detectable changes in the stability of 20S and 26S proteasome complexes which might contribute to imbalanced proteostasis in a chronic setting as observed in chronic lung diseases associated with cigarette smoking.

How many copies of GSTM1 and GSTT1 are associated with head and neck cancer risk?

Purpose: GSTM1 and GSTT1 present a polymorphism that can drive complete gene deletions. The current methodology can powerfully determine GSTM1 and GSTT1 copy number variations (CNVs), which may clarify the real contribution of each gene copies to the cellular detoxification process and tumour risk. However, only analysing the presence/absence of these genes yielded controversial results for several disorders, including cancer. Because head and neck cancer (HNC) is becoming a serious global health problem, this study determined the CNVs of GSTM1 and GSTT1 in an HNC case-control population and investigated the possible association between gene copy numbers and tumour risk. Methods: CNV was evaluated by (Ct) 2^-ΔΔCt qPCR methodology in 619 HNC patients and 448 patients with no tumour diagnosis. Results: The genes copy number range was 0-3. The CNV of GSTM1 and GSTT1 frequencies were similar between the cases and control. Thus, none copy of GSTM1 and GSTT1 were associated with HNC risk. Notwithstanding, one copy of both genes had higher frequencies among individuals who carried GSTM1 and GSTT1. Conclusions: One copy number of GSTM1 and GSTT1 presented a higher frequency among carrier genes, but the CNV of GSTM1 and GSTT1 was not associated with HNC risk.

Cigarette smoke directly impairs skeletal muscle function through capillary regression and altered myofibre calcium kinetics in mice

KEY POINTS

Cigarette smoke components directly alter muscle fatigue resistance and intracellular muscle fibre Ca2+ handling independent of a change in lung structure. Changes in muscle vascular structure are associated with a depletion of satellite cells. Sarcoplasmic reticulum Ca2+ uptake is substantially impaired in myofibres during fatiguing contractions in mice treated with cigarette smoke extract.

ABSTRACT

Cigarette smokers exhibit exercise intolerance before a decline in respiratory function. In the present study, the direct effects of cigarette smoke on limb muscle function were tested by comparing cigarette smoke delivered to mice by weekly injections of cigarette smoke extract (CSE), or nose-only exposure (CS) 5 days each week, for 8 weeks. Cigarette smoke delivered by either route did not alter pulmonary airspace size. Muscle fatigue measured in situ was 50% lower in the CSE and CS groups than in control. This was accompanied by 34% and 22% decreases in soleus capillary-to-fibre ratio of the CSE and CS groups, respectively, and a trend for fewer skeletal muscle actin-positive arterioles (P = 0.07). In addition, fewer quiescent satellite cells (Nes+Pax7+) were associated with soleus fibres in mice with skeletal myofibre VEGF gene deletion (decreased 47%) and CS exposed (decreased 73%) than with control fibres. Contractile properties of isolated extensor digitorum longus and soleus muscles were impaired. In flexor digitorum brevis myofibres isolated from CSE mice, fatigue resistance was diminished by 43% compared to control and CS myofibres, and this was accompanied by a pronounced slowing in relaxation, an increase in intracellular Ca2+ accumulation, and a slowing in sarcoplasmic reticulum Ca2+ uptake. These data suggest that cigarette smoke components may impair hindlimb muscle vascular structure, fatigue resistance and myofibre calcium handling, and these changes ultimately affect contractile efficiency of locomotor muscles independent of a change in lung function.

In vivo exposure to hydroquinone during the early phase of collagen-induced arthritis aggravates the disease

Robust correlation between the severity of rheumatoid arthritis (RA) and cigarette smoking has been clinically demonstrated. Nevertheless, cigarette compounds responsible for this toxic effect and their mechanisms have not been described. Considering that hydroquinone (HQ) is an abundant, pro-oxidative compound of the matter particle phase of cigarette smoke, we investigated whether HQ exposure during the initial phase of collagen-induced arthritis (CIA) could aggravate the disease. For this purpose, male Wistar rats were exposed to aerosolized HQ (25 ppm), saline or 5% ethanol solution (HQ vehicle) for 1 h per day during 14 days. CIA was induced through s.c. injection of bovine collagen Type II (0.4 mg/100 μL) at days seven and 14 of exposure. Clinical signs of disease and the cell profile and chemical mediators in the synovial fluid and membrane were analysed at day 35 after the beginning of exposure. HQ exposure aggravated CIA-related paw edema and increased the cell infiltrate and interleukin-6 (IL-6) levels in the synovial fluid, promoted intense tissue collagen deposition and enhanced synoviocyte proliferation and higher frequency of aryl hydrocarbon receptor (AhR⁺) and interleukin (IL-17⁺) neutrophils in the synovial membrane. in vitro data also highlighted that neutrophils expressed increased levels of AhR, IL-17 and reactive oxygen species (ROS) generation. However, only AhR expression and ROS generation were blocked by in vitro treatment with AhR antagonist. Therefore, we conclude that in vivo HQ exposure at the early phase of AR onset worsens RA, leading to high frequency of AhR/IL-17⁺ neutrophils into the joint.

Hydroquinone exposure worsens the symptomatology of rheumatoid arthritis

The genesis of rheumatoid arthritis (RA) is complex and dependent on genetic background and exposure to environmental xenobiotic. Indeed, smoking is associated to developing and worsening pre-existing RA. Nevertheless, the mechanisms and cigarette compounds involved in the harmful processes have not been elucidated. Here, we investigated if the exposure to hydroquinone (HQ), an abundant pro-oxidative compound of cigarette and benzene metabolite, could worsen the ongoing RA. Hence, collagen-induced arthritis (CIA) was induced in male Wistar rats by s.c. injection of 400 μg (200 μL) of bovine collagen type II emulsified in complete Freund's adjuvant on day 1, and a booster injection was performed on day 7. Exposures to nebulized HQ (25 ppm), saline solution or HQ vehicle solution (5% ethanol in saline) were carried out for 1 h, once a day, on days 21-27 after CIA induction. On day 27, animals were euthanized and samples were collected for further analyses. Exposure to HQ caused loss of weight, intensified paw edema, enhanced levels of tumor necrosis factor-α (TNF-α) and anti-citrullinated protein antibody (ACPA) in the serum; augmented synoviocyte proliferation and influx of aril hydrocarbon receptor (AhR) positive cells into the synovial membrane, altered collagen fibre rearrangement in the synovia, and synoviocytes isolated from HQ exposed rats secreted higher levels of pro-inflammatory cytokines, TNF-α and interleukin-1β. Associated, we point out HQ as an environmental pollutant that aggravates RA, suggesting its participation on worsening RA in smoking patients.

Assessment of glutathione/glutathione disulphide ratio and S-glutathionylated proteins in human blood, solid tissues, and cultured cells

Glutathione (GSH) is the major non-protein thiol in humans and other mammals, which is present in millimolar concentrations within cells, but at much lower concentrations in the blood plasma. GSH and GSH-related enzymes act both to prevent oxidative damage and to detoxify electrophiles. Under oxidative stress, two GSH molecules become linked by a disulphide bridge to form glutathione disulphide (GSSG). Therefore, assessment of the GSH/GSSG ratio may provide an estimation of cellular redox metabolism. Current evidence resulting from studies in human blood, solid tissues, and cultured cells suggests that GSH also plays a prominent role in protein redox regulation via S -glutathionylation, i.e., the conjugation of GSH to reactive protein cysteine residues. A number of methodologies that enable quantitative analysis of GSH/GSSG ratio and S-glutathionylated proteins (PSSG), as well as identification and visualization of PSSG in tissue sections or cultured cells are currently available. Here, we have considered the main methodologies applied for GSH, GSSG and PSSG detection in biological samples. This review paper provides an up-to-date critical overview of the application of the most relevant analytical, morphological, and proteomics approaches to detect and analyse GSH, GSSG and PSSG in mammalian samples as well as discusses their current limitations.

Single Silver Nanoparticle Instillation Induced Early and Persisting Moderate Cortical Damage in Rat Kidneys

The potential toxic effects of silver nanoparticles (AgNPs), administered by a single intratracheal instillation (i.t), was assessed in a rat model using commercial physico-chemical characterized nanosilver. Histopathological changes, overall toxic response and oxidative stress (kidney and plasma protein carbonylation), paralleled by ultrastructural observations (TEM), were evaluated to examine renal responses 7 and 28 days after i.t. application of a low AgNP dose (50 µg/rat), compared to an equivalent dose of ionic silver (7 µg AgNO₃/rat). The AgNPs caused moderate renal histopathological and ultrastructural alteration, in a region-specific manner, being the cortex the most affected area. Notably, the bulk AgNO₃, caused similar adverse effects with a slightly more marked extent, also triggering apoptotic phenomena. Specifically, 7 days after exposure to both AgNPs and AgNO₃, dilatation of the intercapillary and peripheral Bowman’s space was observed, together with glomerular shrinkage. At day 28, these effects still persisted after both treatments, accompanied by an additional injury involving the vascular component of the mesangium, with interstitial micro-hemorrhages. Neither AgNPs nor AgNO₃ induced oxidative stress effects in kidneys and plasma, at either time point. The AgNP-induced moderate renal effects indicate that, despite their benefits, novel AgNPs employed in consumer products need exhaustive investigation to ensure public health safety.

Feasibility and Acceptability of a Text Message-Based Smoking Cessation Program for Young Adults in Lima, Peru: Pilot Study

Background

In Peru’s urban communities, tobacco smoking generally starts during adolescence and smoking prevalence is highest among young adults. Each year, many attempt to quit, but access to smoking cessation programs is limited. Evidence-based text messaging smoking cessation programs are an alternative that has been successfully implemented in high-income countries, but not yet in middle- and low-income countries with limited tobacco control policies.

Objective

The objective was to assess the feasibility and acceptability of an short message service (SMS) text message-based cognitive behavioral smoking cessation program for young adults in Lima, Peru.

Methods

Recruitment included using flyers and social media ads to direct young adults interested in quitting smoking to a website where interested participants completed a Google Drive survey. Inclusion criteria were being between ages 18 and 25 years, smoking at least four cigarettes per day at least 6 days per week, willing to quit in the next 30 days, owning a mobile phone, using SMS text messaging at least once in past year, and residing in Lima. Participants joined one of three phases: (1) focus groups and in-depth interviews whose feedback was used to develop the SMS text messages, (2) validating the SMS text messages, and (3) a pilot of the SMS text message-based smoking cessation program to test its feasibility and acceptability among young adults in Lima. The outcome measures included adherence to the SMS text message-based program, acceptability of content, and smoking abstinence self-report on days 2, 7, and 30 after quitting.

Results

Of 639 participants who completed initial online surveys, 42 met the inclusion criteria and 35 agreed to participate (focus groups and interviews: n=12; validate SMS text messages: n=8; program pilot: n=15). Common quit practices and beliefs emerged from participants in the focus groups and interviews informed the content, tone, and delivery schedule of the messages used in the SMS text message smoking cessation program. A small randomized controlled pilot trial was performed to test the program’s feasibility and acceptability; nine smokers were assigned to the SMS text message smoking cessation program and six to a SMS text message nutrition program. Participant retention was high: 93% (14/15) remained until day 30 after quit day. In all, 56% of participants (5/9) in the SMS text message smoking cessation program reported remaining smoke-free until day 30 after quit day and 17% of participants (1/6) in the SMS text message nutrition program reported remaining smoke-free during the entire program. The 14 participants who completed the pilot reported that they received valuable health information and approved the delivery schedule of the SMS text messages.

Conclusions

This study provides initial evidence that a SMS text message smoking cessation program is feasible and acceptable for young adults residing in Lima.

Statin medication in patients with epiretinal membrane is associated with low intravitreal EPO, TGF-beta-1, and VEGF levels

Background

In eyes with idiopathic epiretinal membrane (iERM), the intravitreal growth factor and cytokine levels may associate with postvitrectomy outcomes. Here, we have analyzed the perioperative intravitreal protein levels of potent vasoactive, proinflammatory, and extracellular matrix-remodeling factors in iERM eyes and evaluated the postvitrectomy outcomes.

Methods

This was an institutional, observational study. Eyes operated on for iERM (n=26) were analyzed according to the use of statin medication. Vitreous samples were subjected to protein measurements of angiopoietin-1 and -2, erythropoietin, transforming growth factor-β1, and vascular endothelial growth factor by enzyme-linked immunosorbent assay, and of matrix metalloproteinase-2 and -9 by gelatin zymography. One-month visual outcomes and 1-year revitrectomy rates were recorded.

Results

In iERM eyes of patients taking statins, intravitreal levels of erythropoietin (mean ± standard deviation, 10.8±4.9 vs 82.9±119.5 mIU/mg, P=0.003), transforming growth factor-β1 (2.3±4.7 vs 15.8±16.3 pg/mg, P=0.035), and vascular endothelial growth factor (5.5±9.9 vs 236.6±491.6 pg/mg, P=0.006) were lower than in nonstatin-treated patients. At 1-month, visual gain did not significantly differ between iERM eyes of patients with statins and those without (improvement 0.27±0.20 vs 0.16±0.38 logarithm of the minimum angle of resolution units, P=0.118).

Conclusion

Systemic statin therapy might have a favorable effect on intravitreal factors involved in vascular permeability, inflammation, and fibroproliferation in aging human iERM eyes.

Association of the manganese superoxide dismutase gene Ala-9Val polymorphism with age of smoking initiation in male schizophrenia smokers

Schizophrenia patients exhibit higher smoking rates than the general population. A growing body of evidence suggests that cigarette smoke impairs the antioxidant defense mechanisms, leading to oxidative damage. Manganese superoxide dismutase (MnSOD) is the major antioxidant in the mitochondria, catalyzing the metabolism of superoxide radicals to form hydrogen peroxide. Since the identification of a well-characterized functional polymorphism, Ala-9Val of MnSOD, a number of studies have evaluated the association between Val-9Ala and schizophrenia or cancer. In this study, we hypothesized that the functional polymorphism of MnSOD Ala-9Val was associated with smoking in patients with schizophrenia. This polymorphism was genotyped in 666 chronic male schizophrenia patients (smoker/never-smoker = 507/159) and 660 male controls (smoker/never-smoker = 360/300) using a case-control design. The cigarettes smoked per day (CPD) and smoking behaviors were evaluated by clinician-administered questionnaires and the Fagerstrom Test for Nicotine Dependence (FTND). The results showed no significant differences in MnSOD Ala-9Val genotype and allele distributions between the patients and healthy controls or between smokers and never-smokers in either patients or healthy controls alone. The smokers with the Ala allele started smoking significantly earlier (19.9 ± 5.8 vs. 21.7 ± 6.5 years, P = 0.005) only in patients. These results suggest that the MnSOD Ala-9Val polymorphism may not influence smoking status in a Chinese male schizophrenia population, but may influence the age at which smoking is started among schizophrenia smokers.

Impact of tobacco smoking on response to tumour necrosis factor-alpha inhibitor treatment in patients with ankylosing spondylitis: results from the Danish nationwide DANBIO registry

OBJECTIVES

To investigate the association between tobacco smoking and disease activity, treatment adherence and treatment responses in patients with AS treated with their first tumour necrosis factor-alpha inhibitor (TNFi) therapy in routine care.

METHODS

Observational cohort study based on the Danish nationwide DANBIO registry. Kaplan-Meier plots, Cox and logistic regression analyses by smoking status (current/never/previous) were calculated for treatment adherence and BASDAI 50%/20 mm-response. Additional stratified analyses were performed for gender and TNFi-type.

RESULTS

Of 1576 AS patients included in the study, 1425(90%) had known smoking status (current/never/previous: 43%/41%/16%). The median follow-up time was 2.02 years (IQR 0.69-5.01). At baseline, current smokers compared with never smokers had longer disease duration (4 years (1-12)/2 years (0-10)), higher BASDAI (61 mm (47-73)/58 mm (44-70)), BASFI (53 mm (35-69)/46 mm (31-66)) and BASMI (40 mm (20-60)/30 mm (10-50)) scores (all P < 0.01). Current and previous smokers had shorter treatment adherence than never smokers (current: 2.30 years (1.81-2.79) (median (95% CI)); previous: 2.48 years (1.56-3.40), never: 4.12 years (3.29-4.95)), P < 0.0001). Similar results were found in multivariate analyses (current versus never smokers, HR 1.41 (95% CI 1.21-1.65), P < 0.001), most pronounced among men. Current smokers had poorer 6 months' BASDAI50%/20 mm-response rate than never smokers (42%/58%, P < 0.001). In multivariate analyses, current smokers had lower odds of achieving BASDAI50%/20 mm-response than never smokers, both overall (OR 0.48 (95% CI 0.35-0.65), P < 0.0001) and for the different TNFi-types (adalimumab 0.45 (0.27-0.76)/etanercept 0.24 (0.10-0.61)/infliximab 0.57 (0.34-0.95)).

CONCLUSION

In this study of TNFi-treated AS patients in clinical practice, current and previous smokers had significantly poorer patient-reported outcomes at baseline, shorter treatment adherence and poorer treatment response compared with never smokers.

α-Tocopherol supplementation reduces 5-nitro-γ-tocopherol accumulation by decreasing γ-tocopherol in young adult smokers

γ-Tocopherol (γ-T) scavenges reactive nitrogen species (RNS) to form 5-NO2-γ-T (NGT). However, α-T supplementation decreases circulating γ-T, which could limit its RNS scavenging activities. We hypothesized that α-T supplementation would mitigate NGT accumulation by impairing γ-T status. Healthy smokers (21 ± 1 y, n = 11) and non-smokers (21 ± 2 y, n = 10) ingested 75 mg/d each of RRR- and all-rac-α-tocopheryl acetate for 6 d. Plasma α-T, γ-T, γ-carboxyethyl hydroxychromanol (CEHC), NGT, and nitrate/nitrite were measured prior to supplementation (Pre), the morning after 6 consecutive evenings of supplementation (Post 1), and on the mornings of d 6 (Post 6) and d 14 (Post 14) during the post-supplementation period. α-T supplementation increased plasma α-T, and decreased γ-T, in both groups and these returned to Pre concentrations on Post 6 regardless of smoking status. Plasma γ-CEHC increased after the first dose of supplementation in both groups, suggesting that α-T supplementation decreased plasma γ-T in part by increasing its metabolism. Plasma NGT and nitrate/nitrite concentrations at Pre were greater in smokers, indicating greater nitrative stress due to cigarette smoking. Plasma NGT concentration was lowered only in smokers on Post 1 and Post 6 and was restored to Pre levels on Post 14. Plasma nitrate/nitrite tended (P = 0.07) to increase post-supplementation only in smokers, supporting decreases in RNS scavenging by γ-T. Plasma NGT concentration was more strongly correlated (P < 0.05) with γ-T in smokers (R = 0.83) compared with non-smokers (R = 0.50), supporting that α-T-mediated decreases in γ-T reduces NGT formation. These data indicate that α-T supplementation limits γ-T scavenging of RNS in smokers by decreasing γ-T availability.

High tobacco consumption lowers body weight: a Mendelian randomization study of the Copenhagen General Population Study

BACKGROUND

Conflicting evidence has been found regarding the association between high tobacco consumption and body weight among smokers. We tested the hypothesis that high tobacco consumption is causally associated with low body weight.

METHODS

We conducted a Mendelian randomization study with a genetic variant in CHRNA3 (rs1051730) as proxy for high tobacco consumption. The cohort consisted of 80,342 participants from the Copenhagen General Population Study, with details on body weight, smoking habits and CHRNA3 genotype, including 15,220 current smokers.

RESULTS

In observational analyses, high tobacco consumption was associated with high body weight, body mass index, waist circumference, hip circumference and waist-hip ratio. In multivariable adjusted models a 1-cigarette/day higher tobacco consumption was associated with 0.05 kg (95% confidence interval 0.02; 0.08) higher body weight, 0.02 kg/m(2) (0.01; 0.02) higher body mass index, 0.10 cm (0.07; 0.12) higher waist circumference and 0.02 cm (0.001; 0.03) higher hip circumference. In contrast, the per-allele increase inCHRNA3 rs1051730 associated with high tobacco consumption was associated with 0.59 kg (0.96; 0.22) lower body weight, 0.23 kg/m(2) (0.33; 0.13) lower body mass index, 0.32 cm (0.74; 0.003) lower waist circumference and 0.45 cm (0.66; 0.24) lower hip circumference. No association was found between tobacco consumption and waist-hip ratio in genetic analysis, or among CHRNA3 genotype and any of the outcome variables in former or never smokers.

CONCLUSIONS

High tobacco consumption causes lower body weight among current smokers. However, smoking does not seem to affect body shape or fat distribution causally. The lack of association between CHRNA3 genotype and body weight among former smokers and never smokers favours smoking as the causal factor for the observed associations.

Cigarette smoke alters the proteomic profile of lung fibroblasts

The protein identified here may offer a new insight into deciphering damage caused by cigarette smoke.

The emerging role of microRNAs in cardiovascular disease

Cardiovascular disease remains the most prevalent cause of human morbidity and mortality in ageing Western societies. Basic and translational scientific efforts have focused on the development and improvement of diagnostic and therapeutic strategies to limit the burden of associated diseases, such as stroke and myocardial infarction, and diabetes mellitus and arterial hypertension. Progress in molecular medicine and biology has unravelled a complex epigenetic and post-transcriptional gene-regulating machinery in humans which may limit disease development. An increasing number of attractive molecular strategies, which use the potential of modulating noncoding RNAs, have surfaced over the last decade. Currently, the most extensively studied gene-regulating RNA subspecies are microRNAs, which have been shown to adjust the translational output of coding transcripts by enforcing their degradation and inhibiting their translation into protein. Key findings indicate that microRNAs act as crucial regulators in the majority of human pathologies. Thus, recent research has focused on detecting and modulating microRNAs for therapeutic and biomarker purposes. This review focuses on main and repeated discoveries regarding the role and the therapeutic and biomarker feasibility of microRNAs during cardiovascular disease development and exacerbation.

The impact of alcohol and tobacco use on in vivo glutathione in youth with bipolar disorder: an exploratory study

Risky alcohol consumption and tobacco smoking is highly prevalent in bipolar disorder (BD) and is associated with increased formation of neural reactive oxygen species. Proton magnetic resonance spectroscopy ((1)H-MRS) is an in vivo imaging modality that allows quantification of glutathione (GSH) concentration, the brains primary antioxidant. Sixty-four patients with BD and 49 controls (18-30 years) completed self-report questionnaires regarding alcohol and tobacco use and underwent (1)H-MRS. Levels of GSH in the hippocampus and anterior cingulate cortex (ACC) were determined. Within-group Pearson's correlations were used to explore the relationship between alcohol use and GSH concentration for BD and controls, covarying for age, gender, family history of alcohol dependence and smoking status. Relationships between GSH and presence/severity of alcohol-induced blackouts were determined using Spearman's correlations. In BD, reduced hippocampal-GSH associated with higher alcohol use (R = -0.489, p < 0.021). Reduction of ACC-GSH with increased drinking was non-significant when controlling for tobacco use. Independent samples t-test revealed a significantly decreased ACC-GSH in smokers with BD (t (53) = 4.162, p < 0.001). In controls, alcohol use was not correlated to GSH in either region. In both patients and controls, reduced hippocampal-GSH was associated with blackout presence/severity, supporting a role for the hippocampus in the continuum of alcohol-induced memory impairments. Our preliminary findings suggest that in youth with BD reduced hippocampal-GSH is associated with risky alcohol use and alcohol and tobacco use is associated with reduced ACC-GSH, highlighting the role of these substances as modifiable risk factors for decreased anti-oxidant capacity in BD.