Heat-not-burn cigarettes induce fulminant acute eosinophilic pneumonia requiring extracorporeal membrane oxygenation

A scoping review of the toxicity and health impact of IQOS

This work aims to summarize the current evidence on the toxicity and health impact of IQOS, taking into consideration the data source. On 1 June 2022, we searched PubMed, Web of Science, and Scopus databases using the terms: 'heated tobacco product', 'heat-not-burn', 'IQOS', and 'tobacco heating system'. The search was time-restricted to update a previous search conducted on 8 November 2021, on IQOS data from 2010-2021. The data source [independent, Philip Morris International (PMI), or other manufacturers] was retrieved from relevant sections of each publication. Publications were categorized into two general categories: 1) Toxicity assessments included in vitro, in vivo, and systems toxicology studies; and 2) The impact on human health included clinical studies assessing biomarkers of exposure and biomarkers of health effects. Generally, independent studies used classical in vitro and in vivo approaches, but PMI studies combined these with modeling of gene expression (i.e. systems toxicology). Toxicity assessment and health impact studies covered pulmonary, cardiovascular, and other systemic toxicity. PMI studies overall showed reduced toxicity and health risks of IQOS compared to cigarettes, but independent data did not always conform with this conclusion. This review highlights some discrepancies in IQOS risk assessment regarding methods, depth, and breadth of data collection, as well as conclusions based on the data source.

Heated tobacco product (IQOS) induced pulmonary infiltrates

Background

Heated tobacco products (HTPs) have been marketed as safer alternatives to conventional cigarettes, but emerging evidence suggests potential respiratory risks. We present a case of pulmonary complications associated with IQOS, a popular HTP, contributing to the growing understanding of these risks.

Case description

A 40-year-old chronic smoker switched to IQOS, consuming 1.5 packs per day. He presented with incidental chest radiographic abnormalities and peripheral eosinophilia. Computed tomography of chest revealed pulmonary nodules and ground glass opacities. Bronchoscopy indicated mild eosinophilia. After ruling out other causes, a lung biopsy was recommended but declined. Discontinuation of IQOS led to symptom resolution and radiographic improvement. This case adds to a limited literature on HTP-induced lung injury, with a unique presentation and favorable response to cessation.

Conclusions

The case highlights potential pulmonary complications and the first describing an organizing pattern of lung injury associated with IQOS use, emphasizing the importance of recognizing and discontinuing HTPs in patients with respiratory symptoms or radiographic abnormalities. Further research is needed to elucidate the mechanisms underlying the harmful effects of HTPs and inform public health policies. This case underscores the importance of monitoring and educating individuals about the potential risks of HTPs to respiratory health, especially in the context of smokers switching to these products.

Immunology in COPD and the use of combustible cigarettes and heated tobacco products

Chronic obstructive pulmonary disease (COPD) is one of the most common chronic respiratory diseases, characterised by high morbidity and mortality. COPD is characterised by a progressive decline of lung function caused by chronic inflammatory reactions in the lung tissue due to continual exposure to harmful molecules by inhalation. As prevention plays a very important role in COPD, quitting smoking is the most important factor in reducing the decline in lung function. Unfortunately, many people are unable to break their nicotine addiction. This paper summarises current knowledge about combustible cigarettes (CSs) and alternative tobacco products such as heated tobacco products (HTPs) in COPD. The paper focuses on the immunological aspects of COPD and the influence of tobacco products on lung tissue immunology. There are differences in research results between HTPs and CSs in favour of HTPs. More long-term studies are needed to look at the effects of HTPs, especially in COPD. However, there is no doubt that it would be best for patients to give up their nicotine addiction completely.

Awareness, Attitudes, and Concerns Regarding Heated Tobacco Products Among Physicians in Japan

BACKGROUND

New tobacco products, particularly heated tobacco products (HTPs), have been introduced across several international markets as alternatives to combustible products, such as cigarettes. However, there are limited studies on physicians' perceptions of HTPs. This study analyzes the awareness of HTPs among physicians and assesses their concerns and attitudes toward patients using HTPs.

METHODS

A self-administered questionnaire was sent to a sample of 7,500 member physicians (6,000 male and 1,500 female) from the Japan Medical Association (JMA). The smoking status of physicians was categorized as never smokers, ever HTP smokers, current HTP smokers, and ever and current smokers of other products. Physicians' awareness and attitudes toward patients using HTPs were analyzed using descriptive statistics. The correlation between the outcomes was examined using logistic regression models, whereas physicians' concerns about HTPs were analyzed using descriptive statistics.

RESULTS

Data were obtained from 5,492 physicians (21.9% women; aged 60.4; standard deviation, 12.1 years) with a response rate of 74.6%. Overall, 76.7% of the physicians had awareness of HTP, and about half of whom asked patients about using HTPs. Physicians who took longer to discuss cessation were more likely to discourage patient use. Smoking status was associated with discouraging HTP use in patients. Physicians who had experience with HTP use were primarily concerned about the products' long-term safety and less about product regulation.

CONCLUSION

Japanese physicians do not have sufficient information and knowledge about HTPs. Therefore, evidence-based guidelines are required to support physicians in advising patients against HTP use.

Association of combustible cigarettes and heated tobacco products use with SARS-CoV-2 infection and severe COVID-19 in Japan: a JASTIS 2022 cross-sectional study

Insufficient evidence has been accumulated regarding associations of heated tobacco products (HTPs) use with coronavirus infection and severity of coronavirus disease 2019 (COVID-19), an ongoing pandemic. We conducted a cross-sectional study using data from an internet questionnaire administered in February 2022 to 30,130 individuals from the general Japanese population (age range, 16-81 years). Single users of HTPs and dual users of combustible cigarettes and HTPs comprised 5.2% and 7.3% of respondents, and 6.7% and 38.0% of those infected (n = 1117). Approximately 70% of infected dual users experienced severe disease. Single users of HTPs and dual users were more likely to be infected with coronavirus than never-users (adjusted odds ratio [aOR] = 1.65/4.66; 95% confidence interval [CI] 1.26-2.15/3.89-5.58). Regarding severity, former and current tobacco users (former/combustible cigarettes/HTPs: aOR = 1.88/3.17/1.90; 95%CI 1.11-3.19/1.77-5.67/1.01-3.59) were more likely to be administered oxygen than never-users, and dual users required oxygen administration the most (aOR = 4.15, 95%CI 2.70-6.36). Use of HTPs may increase risks of coronavirus infection and severe COVID-19. Our results provide an opportunity to consider the safety of tobacco products use, including HTPs, during the COVID-19 pandemic.

Comparative Health Risk Assessment of Heated Tobacco Products versus Conventional Cigarettes

BACKGROUND

Smoking is the largest preventable cause of death in the world with around eight million estimated premature deaths per year. In response to the harmful effects of conventional tobacco products the tobacco industry has launched a new type of products called Heated tobacco products (HTP) and e-cigarettes, which are considered safer for human health than conventional cigarettes.

MATERIALS AND METHODS

The research was conducted by searching the scientific literature using platforms "Google scholar," "PubMed" and "Science Direct." To compare the non-carcinogenic and carcinogenic risk of HTP products and conventional cigarettes, margin of exposure and lifetime excess cancer risk were calculated using data obtained from a scientific literature search.

HTP products have shown a reduced risk to human health compared to the conventional cigarettes, although they still contain compounds that can be dangerous to human health. There is not enough data obtained from independent studies that could safely indicate that these reduced amounts of toxic chemical entities in the composition of HTP do not induce any harmful effect.

CONCLUSION

Further research is needed to determine the harmful effects of HTP aerosol, as well as to tighten the legislation that would limit the production, import and distribution of these products worldwide until their safety for human health is confirmed with a sufficient number of transparent and representative results obtained in independent scientific studies.

Insight into the pulmonary molecular toxicity of heated tobacco products using human bronchial and alveolar mucosa models at air-liquid interface

Heated tobacco products (HTP) are novel nicotine delivery products with limited toxicological data. HTP uses heating instead of combustion to generate aerosol (HTP-smoke). Physiologically relevant human bronchial and alveolar lung mucosa models developed at air-liquid interface were exposed to HTP-smoke to assess broad toxicological response (n = 6-7; ISO puffing regimen; compared to sham; non-parametric statistical analysis; significance: p < 0.05). Elevated levels of total cellular reactive oxygen species, stress responsive nuclear factor kappa-B, and DNA damage markers [8-hydroxy-2'-deoxyguanosine, phosphorylated histone H2AX, cleaved poly-(ADP-Ribose) polymerase] were detected in HTP-smoke exposed bronchial and/or alveolar models. RNA sequencing detected differential regulation of 724 genes in the bronchial- and 121 genes in the alveolar model following HTP-smoke exposure (cut off: p ≤ 0.01; fold change: ≥ 2). Common enriched pathways included estrogen biosynthesis, ferroptosis, superoxide radical degradation, xenobiotics, and α-tocopherol degradation. Secreted levels of interleukin (IL)1ꞵ and IL8 increased in the bronchial model whereas in the alveolar model, interferon-γ and IL4 increased and IL13 decreased following HTP-smoke exposure. Increased lipid peroxidation was detected in HTP-smoke exposed bronchial and alveolar models which was inhibited by ferrostatin-1. The findings form a basis to perform independent risk assessment studies on different flavours of HTP using different puffing topography and corresponding chemical characterization.

Effect of heated tobacco products and traditional cigarettes on pulmonary toxicity and SARS-CoV-2-induced lung injury

Cigarette smoke (CS) significantly contributes to the development of chronic obstructive pulmonary disease (COPD). Heated tobacco products (HTPs), newly developed cigarette products, have been proposed as an alternative for safe cigarette smoking. Although it is plausible to think that replacing traditional cigarettes with HTPs would lower the risks of COPD, this notion requires confirmation by further investigations from sources independent of the tobacco industry. COPD is characterized by an ongoing inflammatory process in the lungs, and the renin-angiotensin system (RAS) has been implicated in the pathogenesis of COPD. Angiotensin-converting enzyme-2 (ACE2) functions as a negative regulator of RAS and has been suggested as a cellular receptor for the causative agent of SARS-CoV-2. It has been shown that smoking is most likely associated with the negative progression and adverse outcomes of SARS-CoV-2. In this study, we found that cigarette smoke extracts from traditional cigarettes (CSE) caused higher cytotoxicity and higher oxidative stress levels than extracts from HTPs (HTPE) in two lung cell lines (Calu-3 and Beas-2B). CSE and HTPE induced RAS activation, MAPK activation, and NF-kB inflammatory pathway activation, resulting in the production of inflammatory cytokines. Furthermore, CSE and a high dose of HTPE reduced tight junction proteins, including claudin 1, E-cadherin, and ZO-1, and disrupted lung epidermal tight junctions at the air-liquid interface (ALI). Finally, CSE and HTPE enhanced the spike protein S1-induced lung injury response. Together, these results suggest that HTPE induced similar lung pathogenesis relevant to COPD and SARS-CoV-2-induced lung injury caused by CSE.

Acute eosinophilic pneumonia caused by nicotine‐free vaping in an adolescent patient: A case report

An 18‐year‐old man was admitted to our hospital with pneumonia 4 days after he initiated vaping. The patient did not show improvement after ceftriaxone and azithromycin treatment. The cell count of the bronchoalveolar lavage fluid (BALF) revealed 64% eosinophils and 18% lymphocytes. Based on the BALF findings, the patient met the current diagnostic criteria and was diagnosed with vaping‐induced acute eosinophilic pneumonia (AEP). AEP caused by nicotine‐free vaping is rare in Japan. Thus, in cases of AEP, the patient's history of cigarette smoking as well as vaping should be considered.

Characterization of Respiratory Symptoms Among Youth Using Heated Tobacco Products in Hong Kong

IMPORTANCE

Heated tobacco products (HTPs) are promoted as less harmful than combustible cigarettes but epidemiological evidence is scarce, especially in youth.

OBJECTIVE

To investigate the associations of persistent respiratory symptoms with HTP use, cigarette use, and dual use among Hong Kong youth.

DESIGN, SETTING, AND PARTICIPANTS

This was a territorywide cross-sectional school-based survey conducted from October 2018 to July 2019 using an anonymous questionnaire. Schools were randomly invited from a proportionate stratified sample in all 18 districts of Hong Kong. Poisson regression models using generalized estimating equations yielded adjusted prevalence ratios (APRs) of respiratory symptoms in (1) former and current HTP (vs never) users in the whole sample and stratified by cigarette use status and (2) exclusive HTP and dual users vs exclusive cigarette users. Statistical analysis was performed from October 2020 to March 2021.

EXPOSURES

Former and current use of cigarettes, HTPs, e-cigarettes, and other tobacco products.

MAIN OUTCOMES AND MEASURES

Respiratory symptoms for 3 consecutive months in the past 12 months.

RESULTS

The study included 33 627 students with a mean (SD) age of 14.8 (1.9) years; 51.3% (18 171) were boys. Respiratory symptoms were reported by 16.3% (n = 5549) of all students, 29.3% (n = 226) of current users of e-cigarettes, 31.2% (n = 314) of current users of cigarettes, and 33.5% (n = 179) of current users of HTPs. Respiratory symptoms were associated with former (APR, 1.30; 95% CI, 1.06-1.59) and current (APR, 1.59; 95% CI, 1.23-2.06) vs never HTP use and current vs never cigarette use (APR, 1.50; 95% CI, 1.30-1.74) after adjusting for various tobacco use. Associations between respiratory symptoms and current vs never HTP use were observed in never (APR, 1.88; 95% CI, 1.36-2.59) and former (APR, 2.15; 95% CI, 1.12-4.12) cigarette users, but not in current cigarette users (APR, 1.24; 95% CI, 0.97-1.59). Respiratory symptoms were associated with exclusive ever HTP use (APR, 1.46, 95% CI, 1.15-1.86) and ever dual use (APR, 1.29; 95% CI, 1.08-1.54) vs exclusive ever cigarette use. There was no association between exclusive current HTP (vs cigarette) use and respiratory symptoms (1.40; 95% CI, 0.93-2.11).

CONCLUSIONS AND RELEVANCE

This cross-sectional study found that former and current HTP use were associated with persistent respiratory symptoms among youth, especially among never and former cigarette users. Respiratory symptoms were more prevalent in ever exclusive HTP users and ever dual users than ever exclusive cigarette users. These findings suggest that using HTPs instead of cigarettes may not reduce health risks.

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.

Heat-Not-Burn cigarette induces oxidative stress response in primary rat alveolar epithelial cells

There has been an increase in the usage of heat-not-burn (HNB) cigarette products. However, their effects on alveolar epithelial cells (AECs) remain unknown. AECs are the target cells of conventional cigarette smoking-related respiratory diseases such as chronic obstructive pulmonary disease, idiopathic pulmonary fibrosis and lung cancer whose pathogenesis involves oxidative stress. In this study, primary rat AECs were isolated, cultured and stimulated by HNB cigarette smoke extract (CSE). Our data indicate that rat AECs exposed to HNB CSE induced oxidative stress response genes (e.g. Hmox-1, Gsta1, Gsta3 and Nqo1). We also compared the oxidative stress response between two different types of AECs, alveolar type I-like (ATI-like) cells and type II (ATII) cells, and between two different types of cigarette, HNB cigarettes and conventional cigarettes. The expressions of Gsta1, Gsta3 and Nqo1 were higher in ATII cells than ATI-like cells in response to HNB and conventional cigarettes, but there was no significant difference in their expression levels between HNB cigarette and conventional cigarette. Taken together, our results suggest that HNB cigarettes have the similar potential as conventional cigarette products to induce oxidative stress response in AECs.

Acute Eosinophilic Pneumonia Induced by Switching from Conventional Cigarette Smoking to Heated Tobacco Product Smoking

Acute eosinophilic pneumonia (AEP) is an acute respiratory illness with diffuse pulmonary infiltrates and pulmonary eosinophilia. While the etiology of AEP remains unclear, a relationship between cigarette smoking and AEP onset has been suggested. The use of heated tobacco products (HTPs) has been growing, but the impact of these products on our health is not fully understood. We herein report a case of AEP that developed after switching from conventional cigarette to HTP smoking. The patient's condition improved after the cessation of HTP smoking and corticosteroid treatment initiation. In cases of AEP, physicians should consider HTPs use as a possible cause.

Recent advances in the understanding of bronchiolitis in adults

Bronchiolitis is injury to the bronchioles (small airways with a diameter of 2 mm or less) resulting in inflammation and/or fibrosis. Bronchioles can be involved in pathologic processes that involve predominantly the lung parenchyma or large airways, but, in some diseases, bronchioles are the main site of injury ("primary bronchiolitis"). Acute bronchiolitis caused by viruses is responsible for most cases of bronchiolitis in infants and children. In adults, however, there is a wide spectrum of bronchiolar disorders and most are chronic. Many forms of bronchiolitis have been described in the literature, and the terminology in this regard remains confusing. In clinical practice, a classification scheme based on the underlying histopathologic pattern (correlates with presenting radiologic abnormalities) facilitates the recognition of bronchiolitis and the search for the inciting cause of the lung injury. Respiratory bronchiolitis is the most common form of bronchiolitis in adults and is usually related to cigarette smoking. Currently, the diagnosis of respiratory bronchiolitis is generally achieved based on the clinical context (smoking history) and chest CT findings. Constrictive (obliterative) bronchiolitis is associated with airflow obstruction and is seen in various clinical contexts including environmental/occupational inhalation exposures, transplant recipients (bronchiolitis obliterans syndrome), and many others. Diffuse idiopathic pulmonary neuroendocrine cell hyperplasia (DIPNECH) is increasingly recognized and can be associated with progressive airflow obstruction related to constrictive bronchiolitis ("DIPNECH syndrome"). Diffuse aspiration bronchiolitis is a form of aspiration-related lung disease that is often unsuspected and confused for interstitial lung disease. Novel forms of bronchiolitis have been described, including lymphocytic bronchiolitis and alveolar ductitis with emphysema recently described in employees at a manufacturing facility for industrial machines. Bronchiolitis is also a component of vaping-related lung injury encountered in the recent outbreak.

Heat Not Burn Tobacco Product-A New Global Trend: Impact of Heat-Not-Burn Tobacco Products on Public Health, a Systematic Review

Introduction: The use of heat-not-burn tobacco products (HnB) is being adopted increasingly as an alternative to smoking combusted products, primarily cigarettes. Substantial controversy has accompanied their marketing and use in the public health context. In this study, we aimed to consider the probable impacts of HnB tobacco products use on public health. Methods: In May 2019, we conducted a systematic review of 15 studies concerning awareness and use of IQOS (abbrv. I Quit Ordinary Smoking) selected from three databases: Cochrane, PubMed, and Embase regarding public health. Results: All key outcomes varied by smoking status: more young adults who were currently smoking reported being aware of, interested in trying, and prone to trying heat-not-burn tobacco products. Interest in trying HnB products was also present among non-smokers, which raises concerns regarding new smokers. Interestingly, susceptibility to trying IQOS (25.1%) was higher than for traditional cigarettes (19.3%), but lower than for e-cigarettes (29.1%). Conclusions: Present studies suggest that HnB tobacco products have the potential to be a reduced risk product for public health compared to conventional cigarettes, considering indirectly the potential effects on the chronic diseases which are traditionally linked to traditional cigarette use as well as second hand exposure, but further studies are needed to determine whether this potential is likely to be realized. The process of HnB tobacco products becoming increasingly popular is of a global scale. Only small differences between countries on different continents regarding popularity and use of HnB tobacco products have been reported.

Electronic cigarettes: where to from here?

Although the usage of electronic (e)-cigarettes (EC) and similar devices has gained in popularity as an apparent smoking cessation strategy, serious concerns are emerging in relation to both the efficacy of this strategy, as well as the inappropriate use of these devices. While the comparative safety of e-cigarettes is based on the reasonable contention that the levels of inhaled toxicants present in the aerosols generated by these devices are considerably lower than those present in tobacco smoke, the perception that they are indeed relatively risk-free is being challenged on several fronts. Notwithstanding lack of convincing evidence of efficacy as a superior smoking cessation strategy, foremost among emerging concerns is the increasing use of electronic nicotine-delivery devices by young never-smokers. Other concerns include increasing levels of sophistication in the design and capacity of these devices in relation to nicotine content and delivery, the potential threat of manipulation of the contents of e-liquids, as well as other additives such as illicit drugs and other potentially toxic agents that can be vaporised. These issues, together with the potential risks to respiratory health, specifically "e-cigarette or vaping product use-associated lung injury" represent the major thrusts of this review.

Extracorporeal Membrane Oxygenation in Severe Acute Eosinophilic Pneumonia

Acute Eosinophilic Pneumonia (AEP) is a potentially fatal cause of hypoxemic respiratory failure characterized by fever, diffuse bilateral pulmonary infiltrates, and pulmonary eosinophilia. Shown to be associated with a number of environmental exposures and lifestyle choices, AEP has a good prognosis when diagnosed early and treated with corticosteroids. In this clinical case report, we detail the presentation, evaluation, diagnosis, and management of a 40-year old male who presented to the emergency department with dyspnea, chills, and diaphoresis. He had a history of pulmonary embolism 8 years prior but was otherwise healthy, though he had re-started smoking cigarettes a week prior to presentation. Initial chest CT scan revealed widespread mixed groundglass and solid airspace opacities; over the next 12 hours, he rapidly decompensated and after not responding to other invasive mechanical ventilation, was emergently cannulated for veno-venous extracorporeal membrane oxygenation (V-V ECMO). Bronchoalveolar lavage later revealed pulmonary eosinophilia, and after an infectious workup was negative, a diagnosis of AEP was reached and the patient was started on corticosteroids. To our knowledge, this is one of few published cases of AEP requiring V-V ECMO for clinical stabilization, highlighting the utility of this treatment modality in severe disease.