ACE-2 expression in the small airway epithelia of smokers and COPD patients: implications for COVID-19

The World Health Organization (WHO) has declared coronavirus disease 2019 (COVID-19) a pandemic [1]. COVID-19 is caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 displays symptoms ranging from mild to severe (pneumonia) that can lead to death in some individuals [2–4]. As of 18 April 2020, there have been 2 280 945 cases of COVID-19 worldwide and 156 354 deaths [5]. SARS-CoV-2 uses the angiotensin-converting enzyme II (ACE-2) as the cellular entry receptor [6]. While the virus can infect individuals of any age, to date, most of the severe cases have been described in those >55 years of age and with significant comorbidities, such as COPD [7]. Here, we determined whether patients with COPD have increased expression of ACE-2 in bronchial epithelial cells in the lower respiratory tract.

Smokers and those with COPD have increased airway expression of ACE-2, which is the entry receptor for the COVID-19 virus. This may explain the increased risk of severe COVID-19 in these subpopulations and highlight the importance of smoking cessation. https://bit.ly/3bC29es

Tobacco smoking and somatic mutations in human bronchial epithelium

Tobacco smoking causes lung cancer1-3, a process that is driven by more than 60 carcinogens in cigarette smoke that directly damage and mutate DNA4,5. The profound effects of tobacco on the genome of lung cancer cells are well-documented6-10, but equivalent data for normal bronchial cells are lacking. Here we sequenced whole genomes of 632 colonies derived from single bronchial epithelial cells across 16 subjects. Tobacco smoking was the major influence on mutational burden, typically adding from 1,000 to 10,000 mutations per cell; massively increasing the variance both within and between subjects; and generating several distinct mutational signatures of substitutions and of insertions and deletions. A population of cells in individuals with a history of smoking had mutational burdens that were equivalent to those expected for people who had never smoked: these cells had less damage from tobacco-specific mutational processes, were fourfold more frequent in ex-smokers than current smokers and had considerably longer telomeres than their more-mutated counterparts. Driver mutations increased in frequency with age, affecting 4-14% of cells in middle-aged subjects who had never smoked. In current smokers, at least 25% of cells carried driver mutations and 0-6% of cells had two or even three drivers. Thus, tobacco smoking increases mutational burden, cell-to-cell heterogeneity and driver mutations, but quitting promotes replenishment of the bronchial epithelium from mitotically quiescent cells that have avoided tobacco mutagenesis.

Association of Smoking Cessation With Subsequent Risk of Cardiovascular Disease

IMPORTANCE

The time course of cardiovascular disease (CVD) risk after smoking cessation is unclear. Risk calculators consider former smokers to be at risk for only 5 years.

OBJECTIVE

To evaluate the association between years since quitting smoking and incident CVD.

DESIGN, SETTING, AND PARTICIPANTS

Retrospective analysis of prospectively collected data from Framingham Heart Study participants without baseline CVD (original cohort: attending their fourth examination in 1954-1958; offspring cohort: attending their first examination in 1971-1975) who were followed up through December 2015.

EXPOSURES

Time-updated self-reported smoking status, years since quitting, and cumulative pack-years.

MAIN OUTCOMES AND MEASURES

Incident CVD (myocardial infarction, stroke, heart failure, or cardiovascular death). Primary analyses included both cohorts (pooled) and were restricted to heavy ever smokers (≥20 pack-years).

RESULTS

The study population included 8770 individuals (original cohort: n = 3805; offspring cohort: n = 4965) with a mean age of 42.2 (SD, 11.8) years and 45% male. There were 5308 ever smokers with a median 17.2 (interquartile range, 7-30) baseline pack-years, including 2371 heavy ever smokers (406 [17%] former and 1965 [83%] current). Over 26.4 median follow-up years, 2435 first CVD events occurred (original cohort: n = 1612 [n = 665 among heavy smokers]; offspring cohort: n = 823 [n = 430 among heavy smokers]). In the pooled cohort, compared with current smoking, quitting within 5 years was associated with significantly lower rates of incident CVD (incidence rates per 1000 person-years: current smoking, 11.56 [95% CI, 10.30-12.98]; quitting within 5 years, 6.94 [95% CI, 5.61-8.59]; difference, -4.51 [95% CI, -5.90 to -2.77]) and lower risk of incident CVD (hazard ratio, 0.61; 95% CI, 0.49-0.76). Compared with never smoking, quitting smoking ceased to be significantly associated with greater CVD risk between 10 and 15 years after cessation in the pooled cohort (incidence rates per 1000 person-years: never smoking, 5.09 [95% CI, 4.52-5.74]; quitting within 10 to <15 years, 6.31 [95% CI, 4.93-8.09]; difference, 1.27 [95% CI, -0.10 to 3.05]; hazard ratio, 1.25 [95% CI, 0.98-1.60]).

CONCLUSIONS AND RELEVANCE

Among heavy smokers, smoking cessation was associated with significantly lower risk of CVD within 5 years relative to current smokers. However, relative to never smokers, former smokers' CVD risk remained significantly elevated beyond 5 years after smoking cessation.

Have combustible cigarettes met their match? The nicotine delivery profiles and harmful constituent exposures of second-generation and third-generation electronic cigarette users

INTRODUCTION

Electronic cigarettes' (e-cigarettes) viability as a public health strategy to end smoking will likely be determined by their ability to mimic the pharmacokinetic profile of a cigarette while also exposing users to significantly lower levels of harmful/potentially harmful constituents (HPHCs). The present study examined the nicotine delivery profile of third- (G3) versus second-generation (G2) e-cigarette devices and their users' exposure to nicotine and select HPHCs compared with cigarette smokers.

METHODS

30 participants (10 smokers, 9 G2 and 11 G3 users) completed baseline questionnaires and provided exhaled carbon monoxide (eCO), saliva and urine samples. Following a 12-hour nicotine abstinence, G2 and G3 users completed a 2-hour vaping session (ie, 5 min, 10-puff bout followed by ad libitum puffing for 115 min). Blood samples, subjective effects, device characteristics and e-liquid consumption were assessed.

RESULTS

Smokers, G2 and G3 users had similar baseline levels of cotinine, but smokers had 4 and 7 times higher levels of eCO (p<0.0001) and total 4-(Methylnitrosamino)-1-(3-pyridyl)-1-butanol (i.e., NNAL, p<0.01), respectively, than G2 or G3 users. Compared with G2s, G3 devices delivered significantly higher power to the atomiser, but G3 users vaped e-cigarette liquids with significantly lower nicotine concentrations. During the vaping session, G3 users achieved significantly higher plasma nicotine concentrations than G2 users following the first 10 puffs (17.5 vs 7.3 ng/mL, respectively) and at 25 and 40 min of ad libitum use. G3 users consumed significantly more e-liquid than G2 users. Vaping urges/withdrawal were reduced following 10 puffs, with no significant differences between device groups.

DISCUSSION

Under normal use conditions, both G2 and G3 devices deliver cigarette-like amounts of nicotine, but G3 devices matched the amount and speed of nicotine delivery of a conventional cigarette. Compared with cigarettes, G2 and G3 e-cigarettes resulted in significantly lower levels of exposure to a potent lung carcinogen and cardiovascular toxicant. These findings have significant implications for understanding the addiction potential of these devices and their viability/suitability as aids to smoking cessation.

Chronic E-Cigarette Exposure Alters the Human Bronchial Epithelial Proteome

RATIONALE

E-cigarettes vaporize propylene glycol/vegetable glycerin (PG/VG), nicotine, and flavorings. However, the long-term health effects of exposing lungs to vaped e-liquids are unknown.

OBJECTIVES

To determine the effects of chronic vaping on pulmonary epithelia.

METHODS

We performed research bronchoscopies on healthy nonsmokers, cigarette smokers, and e-cigarette users (vapers) and obtained bronchial brush biopsies and lavage samples from these subjects for proteomic investigation. We further employed in vitro and murine exposure models to support our human findings.

MEASUREMENTS AND MAIN RESULTS

Visual inspection by bronchoscopy revealed that vaper airways appeared friable and erythematous. Epithelial cells from biopsy samples revealed approximately 300 proteins that were differentially expressed in smoker and vaper airways, with only 78 proteins being commonly altered in both groups and 113 uniquely altered in vapers. For example, CYP1B1 (cytochrome P450 family 1 subfamily B member 1), MUC5AC (mucin 5 AC), and MUC4 levels were increased in vapers. Aerosolized PG/VG alone significantly increased MUC5AC protein in human airway epithelial cultures and in murine nasal epithelia in vivo. We also found that e-liquids rapidly entered cells and that PG/VG reduced membrane fluidity and impaired protein diffusion.

CONCLUSIONS

We conclude that chronic vaping exerts marked biological effects on the lung and that these effects may in part be mediated by the PG/VG base. These changes are likely not harmless and may have clinical implications for the development of chronic lung disease. Further studies will be required to determine the full extent of vaping on the lung.

E-cigarettes use in the United States: reasons for use, perceptions, and effects on health

BACKGROUND

Many researchers claim electronic cigarettes (e-cigarettes) to be a breakthrough invention for tobacco users that aspires to curb their addiction to conventional cigarettes. Claimed to be safer by their promoters, these smokeless devices have become increasingly popular since their arrival on the market among users of all ages, especially adolescents. This paper investigated the trends in e-cigarette usage since the time it arrived in the United States, highlighting the highest surge that has occurred in adolescent e-cigarette use. It also aimed to understand the reasons and perceptions behind the ever-increasing use of e-cigarettes by adolescents.

MAIN BODY

With the advent of e-cigarettes and common positive perceptions regarding their use, we are at risk of reversing the years of efforts regarding tobacco control and instead advance towards a new addiction with currently unknown long-term health hazards. There is substantial data showing a significant increase of e-cigarette users in the United States, especially among adolescents. The aim of this review was to explore the reasons behind this widespread increase in the use of e-cigarettes among the teenage population in the US and also to uncover the common perceptions about these new electronic delivery systems. In addition, this review attempted to summarize health benefits and hazards associated with e-cigarette use as it crucial to have the right information among its users regarding the health effects of e-cigarette use.

CONCLUSION

E-cigarettes are more appealing than c-cigarettes for a variety of reasons, including cost, choice of different flavors, ease of accessibility, and use and impact of social media. There are also different perceptions among e-cigarette users, including both adolescents and adults. The former group may use them because of the sense of fashion associated with this novel device, and the latter might intend to quit conventional/combustible cigarettes (c-cigarettes) by switching to e-cigarettes. However, it is important to note that e-cigarettes are a recent phenomenon; therefore, there is a lack of many long-term studies that can identify future health risks associated with e-cigarette use. We need more detailed studies that focus on the long-term health effects of e-cigarette use. Moreover, with the ever-increasing usage of e-cigarettes by adolescents (10 and 19 years), it is very important that e-cigarettes be incorporated into the current tobacco-free laws and ordinances. We conclude by stating that e-cigarettes need stronger regulations to prevent youth access and use.

Nicotine delivery and users' reactions to Juul compared with cigarettes and other e-cigarette products

AIMS

To assess the pharmacokinetic (PK) profile of, and users' reactions to, Juul (59 mg nicotine/ml) as an indication of its therapeutic and dependence potential.

DESIGN

Cross-over, within-subjects study in which participants attended after overnight abstinence on separate sessions and smoked a cigarette or used Juul or eight other types of e-cigarettes (EC) ad libitum for 5 minutes. The Juul product used was the version available in the United States that has more nicotine in the e-liquid than the one available in the European Union.

SETTING

Laboratory setting in the United Kingdom.

PARTICIPANTS

Twenty dual users (smokers who also vape) provided data on Juul and cigarettes, with eight also providing data on other EC products.

MEASUREMENTS

At each session, number of puffs taken was counted during the 5-minute product use period and blood samples were taken at baseline and at 2, 4, 6, 8, 10 and 30 minutes after starting smoking/vaping and analysed for nicotine. Participants also monitored their urges to smoke and rated the products on a range of characteristics.

FINDINGS

Juul's PK profile was close to the PK profile of cigarettes [maximum concentration (Cmax ) = 20.4 versus 19.2 ng/ml; time to maximum concentration (Tmax ) = 4 versus 6 minutes; area under the curve (AUC): 307.9 versus 312.6, respectively]. Compared with other EC products, Juul had shorter Tmax [4 minutes, (IQR = 2.5-4.0) versus 6.3 minutes, (IQR = 4.7 - 8.1), P = 0.012] and higher Cmax (28.9 (SD = 15.6) versus 10.6 (SD = 5.5), P = 0.013) despite a lower number of puffs (12.5 (SD = 4.2) versus 17.0 (SD = 4.2), P = 0.084). Compared with other e-cigarette products, it also provided faster reduction of urges to smoke and obtained more favourable subjective ratings.

CONCLUSION

Juul's PK profile and user ratings suggest that it could be more effective than other EC products in helping smokers to quit smoking, but it may also have a higher potential to generate regular use in non-smokers.

Mucus Plugs and Emphysema in the Pathophysiology of Airflow Obstruction and Hypoxemia in Smokers

Rationale: The relative roles of mucus plugs and emphysema in mechanisms of airflow limitation and hypoxemia in smokers with chronic obstructive pulmonary disease (COPD) are uncertain.Objectives: To relate image-based measures of mucus plugs and emphysema to measures of airflow obstruction and oxygenation in patients with COPD.Methods: We analyzed computed tomographic (CT) lung images and lung function in participants in the Subpopulations and Intermediate Outcome Measures in COPD Study. Radiologists scored mucus plugs on CT lung images, and imaging software automatically quantified emphysema percentage. Unadjusted and adjusted relationships between mucus plug score, emphysema percentage, and lung function were determined using regression.Measurements and Main Results: Among 400 smokers, 229 (57%) had mucus plugs and 207 (52%) had emphysema, and subgroups could be identified with mucus-dominant and emphysema-dominant disease. Only 33% of smokers with high mucus plug scores had mucus symptoms. Mucus plug score and emphysema percentage were independently associated with lower values for FEV1 and peripheral oxygen saturation (P < 0.001). The relationships between mucus plug score and lung function outcomes were strongest in smokers with limited emphysema (P < 0.001). Compared with smokers with low mucus plug scores, those with high scores had worse COPD Assessment Test scores (17.4 ± 7.7 vs. 14.4 ± 13.3), more frequent annual exacerbations (0.75 ± 1.1 vs. 0.43 ± 0.85), and shorter 6-minute-walk distance (329 ± 115 vs. 392 ± 117 m) (P < 0.001).Conclusions: Symptomatically silent mucus plugs are highly prevalent in smokers and independently associate with lung function outcomes. These data provide rationale for targeting patients with mucus-high/emphysema-low COPD in clinical trials of mucoactive treatments.Clinical trial registered with www.clinicaltrials.gov (NCT01969344).

Is there a smoker's paradox in COVID-19?

Although it is well established that cigarette smoking is associated with morbidity and mortality in several respiratory infections, data from recent studies suggest that active smokers are underrepresented among patients with COVID-19. This has led to claims that a 'smoker's paradox' may exist in COVID-19, wherein smokers are protected from infection and severe complications of COVID-19. We aimed to review and summarise existing literature in this context. Electronic databases were searched for articles that reported prevalence of smokers among patients with COVID-19 or studied any association of smoking with outcomes among patients with COVID-19. We identified several biases and knowledge gaps which may give the false impression that smoking is protective in COVID-19. As of now, the data supporting smoker's paradox claims are limited and questionable. Plausible biologic mechanisms by which smoking might be protective in COVID-19 include an anti-inflammatory effect of nicotine, a blunted immune response in smokers (reducing the risk of a cytokine storm in COVID-19) and increased nitric oxide in the respiratory tract (which may inhibit replication of SARS-CoV-2 and its entry into cells). On the other hand, smoking may worsen susceptibility and prognosis in COVID-19, in a manner similar to other respiratory infections. The claims of a protective effect must be viewed with extreme caution by both the general population as well as clinicians. Further investigations into the interaction between smoking and COVID-19 are warranted to accurately assess the risk of contracting COVID-19 among smokers, and progression to mechanical ventilation or death in patients suffering from it.

Nicotine delivery and cigarette equivalents from vaping a JUULpod

With patented nicotine salt technology, JUUL dominates the e-cigarette market. We reviewed studies of JUUL's nicotine pharmacokinetic profile and studies quantifying nicotine in a JUULpod, emitted in the aerosol and absorbed by users. Examined in eight studies, JUUL's peak nicotine levels were half to three-quarters that of a combustible cigarette in industry-conducted studies with JUUL-naïve users, while comparable to or greater than combustible cigarettes in independent studies of experienced e-cigarette users. JUUL Labs reports each 5% (nicotine-by-weight) cartridge contains approximately 40 mg nicotine per pod and is 'approximately equivalent to about 1 pack of cigarettes.' In five independent studies, nicotine in the liquid in a JUULpod ranged from 39.3 to 48.3 mg. Seven studies measured nicotine delivery via vaping-machine generated aerosols, varying in puffing regimes and equipment. One study estimated 68% transfer efficiency to the aerosol, measuring 28.8 mg nicotine per JUULpod. The other studies reported nicotine values ranging from 72 to 164 µg/puff. At 200 puffs, this is 14.4-32.8 mg of nicotine per pod with equivalence to 13-30 cigarettes. A study measuring nicotine levels in JUUL users during a 5-day controlled switch found equivalence to 18 cigarettes. One JUULpod appears capable of delivering the nicotine equivalent to smoking about a pack of cigarettes, with variability. In JUUL-naïve smokers, JUUL's nicotine boost was lower than that of combustible cigarettes; while in experienced users, JUUL was comparable. Minimising harshness and adaptive to user experience, JUUL's design facilitates initiation to a high nicotine, and ultimately, highly addictive vaping product.

Exposure to Heated Tobacco Products and Adverse Health Effects, a Systematic Review

Heated tobacco products (HTP) are a form of nicotine delivery intended to be an alternative to traditional cigarettes. HTP tobacco products are sold to consumers as a less harmful alternative to traditional cigarettes, both for users and bystanders. The actual impact of HTP on the health of users and its overall impact on public health is still not fully known. A systematic search of the literature was carried out to identify relevant studies published in English from 2015 to February 2021. The following databases were used: PubMed, Scopus, Elsevier and ClinicalKey. 25 studies (independent and sponsored by the tobacco industry) were considered. The analysis of exposure biomarkers and cardiovascular and respiratory biomarkers showed differences between smokers and people using heated tobacco products. Improvements in clinically relevant risk markers, especially cholesterol, sICAM-1, 8-epi-PGF2α, 11-DTX-B2, HDL and FEV1, were observed compared to persistent cigarette smokers. On the other hand, exposure to IQOS has been reported to alter mitochondrial function, which may further exaggerate airway inflammation, airway remodeling and lung cancer. These products have the potential to increase oxidative stress and increase respiratory tract infections by increasing microbial adherence to the respiratory tract. Our review suggests that HTP products may be products with a reduced risk of chronic diseases, including respiratory and cardiovascular diseases and cancer compared to traditional smoking, although in the case of non-smokers so far, they may pose a risk of their occurrence. Research seems to be necessary to assess the frequency of HTP use and its potential negative health effects.

Lung Screen Uptake Trial (LSUT): Randomized Controlled Clinical Trial Testing Targeted Invitation Materials

Rationale: Low uptake of low-dose computed tomography (LDCT) lung cancer screening, particularly by current smokers of a low socioeconomic position, compromises effectiveness and equity.Objectives: To compare the effect of a targeted, low-burden, and stepped invitation strategy versus control on uptake of hospital-based Lung Health Check appointments offering LDCT screening.Methods: In a two-arm, blinded, between-subjects, randomized controlled trial, 2,012 participants were selected from 16 primary care practices using these criteria: 1) aged 60 to 75 years, 2) recorded as a current smoker within the last 7 years, and 3) no prespecified exclusion criteria contraindicating LDCT screening. Both groups received a stepped sequence of preinvitation, invitation, and reminder letters from their primary care practitioner offering prescheduled appointments. The key manipulation was the accompanying leaflet. The intervention group's leaflet targeted psychological barriers and provided low-burden information, mimicking the concept of the U.K. Ministry of Transport's annual vehicle test ("M.O.T. For Your Lungs").Measurements and Main Results: Uptake was 52.6%, with no difference between intervention (52.3%) and control (52.9%) groups in unadjusted (odds ratio [OR], 0.98; 95% confidence interval [CI], 0.82-1.16) or adjusted (OR, 0.98; 95% CI, 0.82-1.17) analyses. Current smokers were less likely to attend (adjusted OR, 0.70; 95% CI, 0.56-0.86) than former smokers. Socioeconomic deprivation was significantly associated with lower uptake for the control group only (P < 0.01).Conclusions: The intervention did not improve uptake. Regardless of trial arm, uptake was considerably higher than previous clinical and real-world studies, particularly given that the samples were predominantly lower socioeconomic position smokers. Strategies common to both groups, including a Lung Health Check approach, could represent a minimum standard.Clinical trial registered with www.clinicaltrials.gov (NCT02558101) and registered prospectively with the International Standard Registered Clinical/Social Study (N21774741).

Body burden of toxic metals and rare earth elements in non-smokers, cigarette smokers and electronic cigarette users

Smoking is considered an important source for inorganic elements, most of them toxic for human health. During the last years, there has been a significant increase in the use of e-cigarettes, although the role of them as source of inorganic elements has not been well established. A cross-sectional study including a total of 150 subjects from Brasov (Romania), divided into three groups (non-smokers, cigarette smokers and electronic cigarettes smokers) were recruited to disclose the role of smoking on the human exposure to inorganic elements. Concentration of 42 elements, including trace elements, elements in the ATSDR's priority pollutant list and rare earth elements (REE) were measured by ICP-MS in the blood serum of participants. Cigarette smokers showed the highest levels of copper, molybdenum, zinc, antimony, and strontium. Electronic cigarette (e-cigarette) users presented the highest concentrations of selenium, silver, and vanadium. Beryllium, europium and lanthanides were detected more frequently among e-cigarette users (20.6%, 23.5%, and 14.7%) than in cigarette smokers (1.7%, 19.0%, and 12.1%, respectively); and the number of detected REE was also higher among e-cigarette users (11.8% of them showed more than 10 different elements). Serum levels of cerium and erbium increased as the duration of the use of e-cigarettes was longer. We have found that smoking is mainly a source of heavy metals while the use of e-cigarettes is a potential source of REE. However, these elements were detected at low concentrations.

Exhaustion of Airway Basal Progenitor Cells in Early and Established Chronic Obstructive Pulmonary Disease

RATIONALE

Up to 40% of smokers develop chronic obstructive pulmonary disease (COPD) over a period that spans decades. Despite the importance of COPD, much remains to be learned about susceptibility and pathogenesis, especially during early, prediagnostic stages of disease. Airway basal progenitor cells are crucial for lung health and resilience because of their ability to repair injured airways. In COPD, the normal airway epithelium is replaced with increased basal and secretory (mucous) cells and decreased ciliated cells, suggesting that progenitors are impaired.

OBJECTIVES

To examine airway basal progenitor cells and lung function in smokers with and without COPD.

METHODS

Bronchial biopsies taken from smokers at risk for COPD and lung cancer were used to acquire airway basal progenitor cells. They were evaluated for count, self-renewal, and multipotentiality (ability to differentiate to basal, mucous, and ciliated cells), and progenitor count was examined for its relationship with lung function.

MEASUREMENTS AND MAIN RESULTS

Basal progenitor count, self-renewal, and multipotentiality were all reduced in COPD versus non-COPD. COPD progenitors produced an epithelium with increased basal and mucous cells and decreased ciliated cells, replicating the COPD phenotype. Progenitor depletion correlated with lung function and identified a subset of subjects without COPD with lung function that was midway between non-COPD with high progenitor counts and those with COPD.

CONCLUSIONS

Basal progenitor dysfunction relates to the histologic and physiologic manifestations of COPD and identifies a subset that may represent an early, prediagnostic stage of COPD, indicating that progenitor exhaustion is involved in COPD pathogenesis.

Does COVID19 Infect the Brain? If So, Smokers Might Be at a Higher Risk

COVID19 is a devastating global pandemic with epicenters in China, Italy, Spain, and now the United States. While the majority of infected cases appear mild, in some cases, individuals present serious cardiorespiratory complications with possible long-term lung damage. Infected individuals report a range of symptoms from headaches to shortness of breath to taste and smell loss. To that end, less is known about how the virus may impact different organ systems. The SARS-CoV2 virus, which is responsible for COVID19, is highly similar to SARS-CoV. Both viruses have evolved an ability to enter host cells through direct interaction with the angiotensin converting enzyme (ACE) 2 protein at the surface of many cells. Published findings indicate that SARS-CoV can enter the human nervous system with evidence from both postmortem brains and detection in cerebrospinal fluid of infected individuals. Here, we consider the ability of SARS-CoV2 to enter and infect the human nervous system based on the strong expression of the ACE2 target throughout the brain. Moreover, we predict that nicotine exposure through various kinds of smoking (cigarettes, electronic cigarettes, or vape) can increase the risk for COVID19 neuroinfection based on known functional interactions between the nicotinic receptor and ACE2. We advocate for higher surveillance and analysis of neurocomplications in infected cases. SIGNIFICANCE STATEMENT: The COVID19 epidemic has spurred a global public health crisis. While many of the cases requiring hospitalization and intensive medical care center on cardiorespiratory treatment, a growing number of cases present neurological symptoms. Viral entry into the brain now appears a strong possibility with deleterious consequences and an urgent need for addressing.

Subtyping COPD by Using Visual and Quantitative CT Imaging Features

BACKGROUND

Multiple studies have identified COPD subtypes by using visual or quantitative evaluation of CT images. However, there has been no systematic assessment of a combined visual and quantitative CT imaging classification. We integrated visually defined patterns of emphysema with quantitative imaging features and spirometry data to produce a set of 10 nonoverlapping CT imaging subtypes, and we assessed differences between subtypes in demographic features, physiological characteristics, longitudinal disease progression, and mortality.

METHODS

We evaluated 9,080 current and former smokers in the COPDGene study who had available volumetric inspiratory and expiratory CT images obtained using a standardized imaging protocol. We defined 10 discrete, nonoverlapping CT imaging subtypes: no CT imaging abnormality, paraseptal emphysema (PSE), bronchial disease, small airway disease, mild emphysema, upper lobe predominant centrilobular emphysema (CLE), lower lobe predominant CLE, diffuse CLE, visual without quantitative emphysema, and quantitative without visual emphysema. Baseline and 5-year longitudinal characteristics and mortality were compared across these CT imaging subtypes.

RESULTS

The overall mortality differed significantly between groups (P < .01) and was highest in the 3 moderate to severe CLE groups. Subjects having quantitative but not visual emphysema and subjects with visual but not quantitative emphysema were unique groups with mild COPD, at risk for progression, and with likely different underlying mechanisms. Subjects with PSE and/or moderate to severe CLE had substantial progression of emphysema over 5 years compared with findings in subjects with no CT imaging abnormality (P < .01).

CONCLUSIONS

The combination of visual and quantitative CT imaging features reflects different underlying pathological processes in the heterogeneous COPD syndrome and provides a useful approach to reclassify types of COPD.

TRIAL REGISTRY

ClinicalTrials.gov; No.: NCT00608764; URL: www.clinicaltrials.gov.

E-cigarette use and combustible tobacco cigarette smoking uptake among non-smokers, including relapse in former smokers: umbrella review, systematic review and meta-analysis

OBJECTIVE

To review and summarise the current evidence on the uptake of combustible cigarette smoking following e-cigarette use in non-smokers-including never-smokers, people not currently smoking and past smokers-through an umbrella review, systematic review and meta-analysis.

DESIGN

Umbrella review, systematic review and meta-analysis.

DATA SOURCES

PubMed, Scopus, Web of Science, PsychINFO (Ovid), Medline (Ovid) and Wiley Cochrane Library up to April 2020.

RESULTS

Of 6225 results, 25 studies of non-smokers-never, not current and former smokers-with a baseline measure of e-cigarette use and an outcome measure of combustible smoking uptake were included. All 25 studies found increased risk of smoking uptake with e-cigarette exposure, although magnitude varied substantially. Using a random-effects model, comparing e-cigarette users versus non-e-cigarette users, among never-smokers at baseline the OR for smoking initiation was 3.25 (95% CI 2.61 to 4.05, I2 85.7%) and among non-smokers at baseline the OR for current smoking was 2.87 (95% CI 1.97 to 4.19, I2 90.1%). Among former smokers, smoking relapse was higher in e-cigarette users versus non-users (OR=2.40, 95% CI 1.50 to 3.83, I2 12.3%).

CONCLUSIONS

Across multiple settings, non-smokers who use e-cigarettes are consistently more likely than those avoiding e-cigarettes to initiate combustible cigarette smoking and become current smokers. The magnitude of this risk varied, with an average of around three times the odds. Former smokers using e-cigarettes have over twice the odds of relapse as non-e-cigarettes users. This study is the first to our knowledge to review and pool data on the latter topic.

PROSPERO REGISTRATION NUMBER

CRD42020168596.

Sleep quality in cigarette smokers: Associations with smoking-related outcomes and exercise

INTRODUCTION

Compared to the general population, cigarette smokers report poorer sleep quality. Poor sleep quality in cigarette smokers is associated with greater nicotine dependence. While exercise is known to improve sleep quality in the general population, less is known about how exercise effects sleep in those who smoke. The goal of this study was to explore the relationships between exercise, sleep, and smoking in cigarette smokers.

METHODS

Data on sleep quality (Insomnia Severity Index (ISI) and Pittsburgh Sleep Quality Index (PSQI)), smoking-related outcomes (e.g., cigarettes/day, Fagerstrom Test for Nicotine Dependence, Minnesota Nicotine and Withdrawal Scale, and Questionnaire of Smoking Urges) and exercise (Fitbit activity measures) were collected for 32 participants (63% female, mean age 30.3 ± 1.0 years) participating in a 12-week clinical research study. Analyses included simple linear regression models.

RESULTS

Overall, participants reported poor sleep quality at baseline (PSQI > 5). Poorer sleep quality at baseline was associated with increased withdrawal (β = 1.63 ± 0.53, p = 0.0043), craving (β = 0.51 ± 0.43, p = 0.2471), and total smoking urges (β = 1.10 ± 0.41, p = 0.0118). During follow-up (i.e., from baseline to week 12), a daily increase in exercise was associated with improved sleep quality over the same time period (PSQI: β = -0.82 ± 0.35, p = 0.0379).

CONCLUSION

Our data suggest that better sleep quality may be associated with lower levels of withdrawal, craving, and smoking urges. Further, exercise may be associated with better sleep quality in cigarette smokers. Future work should explore how increasing exercise and improving sleep quality could inform future smoking cessation interventions.

Tobacco smoking and the risk of abdominal aortic aneurysm: a systematic review and meta-analysis of prospective studies

Several studies have found that smoking increases the risk of abdominal aortic aneurysm, however, the strength of the association has differed between studies and data from cohort studies have not yet been summarized. A systematic review and meta-analysis was therefore conducted to clarify this association. We searched PubMed and Embase databases up to May 2nd 2018. A random effects model was used to estimate summary relative risks (RRs) and 95% confidence intervals (CIs). Twenty three prospective studies were included. Comparing current, former and ever smokers with never smokers the summary RRs were 4.87 (95% CI: 3.93-6.02, I2 = 92%, n = 20), 2.10 (95% CI: 1.76-2.50, I2 = 71%, n = 15) and 3.28 (95% CI: 2.60-4.15, I2 = 96%, n = 18), respectively. The summary RR was 1.87 (95% CI: 1.45-2.40, I2 = 97%) per 10 cigarettes per day, 1.78 (95% CI: 1.54-2.06, I2 = 83%) per 10 pack-years was and 0.45 (95% CI: 0.32-0.63, I2 = 92.3%) per 10 years of smoking cessation. There was evidence of nonlinearity for cigarettes per day and pack-years (pnonlinearity < 0.0001 and pnonlinearity = 0.02, respectively), but not for smoking cessation, pnonlinearity = 0.85. Among smokers who quit, the RR was similar to that of never smokers by 25 years of smoking cessation. These findings confirm a strong association between smoking and the risk of developing abdominal aortic aneurysms.

Impact of Tobacco Versus Electronic Cigarette Smoking on Platelet Function

Electronic cigarettes (E-cigarettes) have become popular as substitutes for conventional tobacco cigarettes or to aid quitting, but little is known about the potential risks to cardiovascular health for smokers and nonsmokers. We sought to compare the impact of E-cigarettes with conventional cigarettes on platelet function in healthy adult smokers and nonsmokers. A crossover single-blind study in 40 healthy participants (20 smokers, 20 nonsmokers, matched for age and sex) was conducted. Each participant smoked a conventional cigarette then returned 1 week later to vape a study E-cigarette with the same nominal nicotine content. Blood samples were drawn shortly before and 5 minutes after each episode and analyzed for platelet aggregation, soluble CD40-ligand (sCD40L) and soluble P-selectin (sP-selectin). At baseline, smokers had significantly higher levels of sCD40L and sP-selectin (all p ≤0.01) than nonsmokers. Within 5 minutes of using either a conventional cigarette or E-cigarette, changes in the levels of sCD40L, sP-selectin, and platelet aggregation (all p ≤0.01) were detectable in both smokers and nonsmokers. In smokers, there were no significant changes in sCD40L and sP-selectin but there was a significant increase in platelet aggregation. In nonsmokers, there was a significant increase in all markers of platelet activation following both cigarette and E-cigarette use. Both traditional and E-cigarettes have short-term effects on platelet activation, although in nonsmokers the use of E-cigarettes had a less important impact. In conclusion, we provide the first comparison data of the acute impact of Tobacco-cigarette and E-cigarette smoking on the platelet function in smokers and nonsmokers.

Dissemination of Mycobacterium abscessus via global transmission networks

Mycobacterium abscessus, a multidrug-resistant nontuberculous mycobacterium, has emerged as a major pathogen affecting people with cystic fibrosis (CF). Although originally thought to be acquired independently from the environment, most individuals are infected with one of several dominant circulating clones (DCCs), indicating the presence of global transmission networks of M. abscessus. How and when these clones emerged and spread globally is unclear. Here, we use evolutionary analyses of isolates from individuals both with and without CF to reconstruct the population history, spatiotemporal spread and recent transmission networks of the DCCs. We demonstrate synchronous expansion of six unrelated DCCs in the 1960s, a period associated with major changes in CF care and survival. Each of these clones has spread globally as a result of rare intercontinental transmission events. We show that the DCCs, but not environmentally acquired isolates, exhibit a specific smoking-associated mutational signature and that current transmission networks include individuals both with and without CF. We therefore propose that the DCCs initially emerged in non-CF populations but were then amplified and spread through the CF community. While individuals with CF are probably the most permissive host, non-CF individuals continue to play a key role in transmission networks and may facilitate long-distance transmission.

Effects of anxiety sensitivity reduction on smoking abstinence: An analysis from a panic prevention program

OBJECTIVE

Scientific evidence implicates anxiety sensitivity (AS) as a risk factor for poor smoking cessation outcomes. Integrated smoking cessation programs that target AS may lead to improved smoking cessation outcomes, potentially through AS reduction. Yet, little work has evaluated the efficacy of integrated smoking cessation treatment on smoking abstinence. The present study prospectively examined treatment effects of a novel AS reduction-smoking cessation intervention relative to a standard smoking cessation intervention on smoking abstinence.

METHOD

Participants (N = 529; 45.9% male; Mage = 38.23, SD = 13.56) included treatment-seeking smokers who received either a 4-session integrated anxiety-reduction and smoking cessation intervention (Smoking Treatment and Anxiety Management Program; [STAMP]) or a 4-session standard smoking cessation program (SCP). The primary aims focused on examining the effects of STAMP on (a) AS reduction during treatment, (b) early and late smoking point prevalence abstinence, and (c) the mechanistic function of AS reduction on treatment effects across early and late smoking abstinence.

RESULTS

Results indicated a significantly greater decline in AS in STAMP relative to SCP (B = -.72, p < .001). Treatment condition did not significantly directly predict early or late abstinence. However, the effect of STAMP on early abstinence was significantly mediated by reductions in AS (indirect = .16, 95% CI [.02, .40]).

CONCLUSIONS

Findings provide evidence for the efficacy of a novel, integrated anxiety and smoking cessation treatment to reduce AS. Moreover, the meditation pathway from STAMP to early abstinence through reductions in AS suggest that AS is a clinically important mechanism of change for smoking cessation treatment and research. (PsycINFO Database Record

The sputum microbiome is distinct between COPD and health, independent of smoking history

BACKGROUND

Airway bacterial dysbiosis is a feature of chronic obstructive pulmonary disease (COPD). However, there is limited comparative data of the lung microbiome between healthy smokers, non-smokers and COPD.

METHODS

We compared the 16S rRNA gene-based sputum microbiome generated from pair-ended Illumina sequencing of 124 healthy subjects (28 smokers and 96 non-smokers with normal lung function), with single stable samples from 218 COPD subjects collected from three UK clinical centres as part of the COPDMAP consortium.

RESULTS

In healthy subjects Firmicutes, Bacteroidetes and Actinobacteria were the major phyla constituting 88% of the total reads, and Streptococcus, Veillonella, Prevotella, Actinomyces and Rothia were the dominant genera. Haemophilus formed only 3% of the healthy microbiome. In contrast, Proteobacteria was the most dominant phylum accounting for 50% of the microbiome in COPD subjects, with Haemophilus and Moraxella at genus level contributing 25 and 3% respectively. There were no differences in the microbiome profile within healthy and COPD subgroups when stratified based on smoking history. Principal coordinate analysis on operational taxonomic units showed two distinct clusters, representative of healthy and COPD subjects (PERMANOVA, p = 0·001).

CONCLUSION

The healthy and COPD sputum microbiomes are distinct and independent of smoking history. Our results underline the important role for Gammaproteobacteria in COPD.

Dual use of electronic and conventional cigarettes is associated with higher cardiovascular risk factors in Korean men

Most smokers who use electronic cigarettes (e-cigarettes) to stop smoking simultaneously use conventional cigarettes (dual users). We aimed to compare the prevalence of cardiovascular risk factors among dual users, cigarette-only smokers, and never smokers in Korean men. We used data acquired from Korean National Health and Nutrition Examination Survey (2013-2017) pertaining to 7,505 male participants aged 19 years or older. About 85% of e-cigarette users were dual users. Dual users had greater nicotine dependence and higher urinary cotinine levels than cigarette-only smokers. Dual users had more psychosocial and behavioural risk factors, including perceived high stress, depressive mood, high daily intake of energy, and obesity, than never smokers and cigarette-only smokers. The prevalence of metabolic syndrome (MetS) was higher among dual users, and their multivariate-adjusted prevalence odds ratio for MetS was 2.79 (P < 0.001) compared with never smokers and 1.57 (P = 0.038) compared with cigarette-only smokers. Given that most e-cigarette users are dual users and dual users are more vulnerable to cardiovascular risk factors than cigarette-only smokers and never smokers, more active treatment for smoking cessation and intensive lifestyle interventions for dual users should be considered with priority.

Decreased surfactant lipids correlate with lung function in chronic obstructive pulmonary disease (COPD)

Smoke exposure is known to decrease total pulmonary surfactant and alter its composition, but the role of surfactant in chronic obstructive pulmonary disease (COPD) remains unknown. We aimed to analyze the compositional changes in the surfactant lipidome in COPD and identify specific lipids associated with pulmonary function decline. Bronchoalveolar lavage (BAL) fluid was obtained from 12 former smokers with COPD and 5 non-smoking, non-asthmatic healthy control volunteers. Lipids were extracted and analyzed by liquid chromatography and mass spectrometry. Pulmonary function data were obtained by spirometry, and correlations of lung function with lipid species were determined. Wild-type C57BL/6 mice were exposed to 6 months of second-hand smoke in a full-body chamber. Surfactant lipids were decreased by 60% in subjects with COPD. All phospholipid classes were dramatically decreased, including ether phospholipids, which have not been studied in pulmonary surfactant. Availability of phospholipid, cholesterol, and sphingomyelin in BAL strongly correlated with pulmonary function and this was attributable to specific lipid species of phosphatidylcholine with surface tension reducing properties, and of phosphatidylglycerol with antimicrobial roles, as well as to other less studied lipid species. Mice exposed to smoke for six months recapitulated surfactant lipidomic changes observed in human subjects with COPD. In summary, we show that the surfactant lipidome is substantially altered in subjects with COPD, and decreased availability of phospholipids correlated with decreased pulmonary function. Further investigation of surfactant alterations in COPD would improve our understanding of its physiopathology and reveal new potential therapeutic targets.