Electronic Cigarettes Are as Toxic to Skin Flap Survival as Tobacco Cigarettes

The impact of e-cigarette exposure on different organ systems: A review of recent evidence and future perspectives

The use of electronic cigarettes (e-cigs) is rapidly increasing worldwide and is promoted as a smoking cessation tool. The impact of traditional cigs on human health has been well-defined in both animal and human studies. In contrast, little is known about the adverse effects of e-cigs exposure on human health. This review summarizes the impact of e-cigs exposure on different organ systems based on the rapidly expanding recent evidence from experimental and human studies. A number of growing studies have shown the adverse effects of e-cigs exposure on various organ systems. The summarized data in this review indicate that while e-cigs use causes less adverse effects on different organs compared to traditional cigs, its long-term exposure may lead to serious health effects. Data on short-term organ effects are limited and there is no sufficient evidence on long-term organ effects. Moreover, the adverse effects of secondhand and third hand e-cigs vapour exposure have not been thoroughly investigated in previous studies. Although some studies demonstrated e-cigs used as a smoking cessation tool, there is a lack of strong evidence to support it. While some researchers suggested e-cigs as a safer alternative to tobacco smoking, their long-term exposure health effects remain largely unknown. Therefore, more epidemiological and prospective studies including mechanistic studies are needed to address the potential adverse health effects of e-cigs to draw a firm conclusion about their safe use. A wide variation in e-cigs products and the lack of standardized testing methods are the major barriers to evaluating the existing data. Specific regulatory guidelines for both e-cigs components and the manufacturing process may be effective to protect consumer health.

The implications of vaping on surgical wound healing: A systematic review

BACKGROUND

E-cigarette use is rapidly growing, and little is known about the postoperative complications. Cigarette smoking has been well-established to be associated with delayed wound healing and increased complications in surgical patients. Due to the intricate and harmonious nature of the wound-healing process, vaping may impair tissue regeneration, posing a risk for patients undergoing surgery. This systematic review aimed to review the evidence on the implications of vaping on wound healing.

METHODS

A systematic search of PubMed and Scopus databases was conducted on October 2022 per Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The following keywords were used to conduct the search: vaping, vape, e-cigarettes, electronic cigarettes, wound healing, tissue regeneration, postoperative complications, wound infection, and blood flow.

RESULTS

Of 5,265 screened articles, only 37 were eligible for qualitative synthesis. A total of 18 articles studied the effect of e-cigarettes on human volunteers, 14 investigated e-cigarette extract on human cell lines, and 5 used animal rat models.

CONCLUSION

Despite limited objective data, the recommendation is that e-cigarettes be treated as tobacco cigarettes; hence, vaping should be stopped in the perioperative period to decrease the incidence of wound healing complications. Clinical trials are required to understand the health hazards of e-cigarettes further and maximize patient safety and clinical outcomes.

Impact of Electronic Cigarettes on the Upper Aerodigestive Tract: A Comprehensive Review for Otolaryngology Providers

Objective

The use and effects of electronic (e)-cigarettes (e-cigs) are particularly relevant for otolaryngology providers as tobacco plays a major role in benign and malignant diseases of the upper aerodigestive tract. This review aims to (1) summarize the recent policies regarding e-cigs and important patterns of use and (2) serve as a comprehensive resource for clinical providers on the known biologic and clinical effects of e-cigs on the upper aerodigestive tract.

Data Sources

PubMed/MEDLINE.

Review Methods

We conducted a narrative review on (1) general information on e-cig use and informative findings in the lower respiratory system and a comprehensive review on (2) the effects of e-cigs on cell and animal models and the clinical implications of these products on human health as is relevant to otolaryngology.

Conclusions

Although e-cigs are likely less harmful than conventional cigarettes, preliminary research on e-cigs suggest several deleterious effects including in the upper aerodigestive tract. Due to this, there has been increased interest in restricting e-cig usage, particularly among the adolescent population, and caution in recommending e-cigs to current smokers.

Implications for Practice

Chronic e-cig use is likely to have clinical implications. It is critical for otolaryngology providers to be aware of the rapidly changing regulations and use patterns regarding e-cigs and how e-cigs influence human health, particularly with regards to the upper aerodigestive tract, to accurately council patients regarding potential risks and benefits of use.

Is There a Smoking Gun for Nicotine? A Review of the Role of Nicotine in Dermatologic Surgery

BACKGROUND

Dermatologic surgeons are faced with a dilemma when counseling actively smoking patients who require dermatologic surgery: recommend total cessation of all nicotine that is associated with extremely high rates of cessation failure or recommend nicotine replacement therapy (NRT).

OBJECTIVE

To determine the safety of NRT in dermatologic surgery.

MATERIALS AND METHODS

PubMed was queried: [(nicotine OR electronic cigarettes) AND (flap OR wound healing)].

RESULTS

Smoking tobacco is detrimental to wound healing, supported by ample evidence (1A). Perioperative smoking cessation reduces risk (1B). Basic science demonstrates both a benefit and detriment of nicotine depending on the factor studied (2A). Human studies suggest no detrimental effect of nicotine on perioperative complications (1B). Nicotine may be detrimental to flaps, but evidence is limited to basic science (2A).

CONCLUSION

Dermatologists should consider recommending nicotine replacement for smokers in the perioperative period. Evidence is lacking to determine safety in flaps. It is presumed based on animal studies that nicotine has a negative effect on flaps; however, it is likely less than tobacco. Weighing the risk of cessation failure without nicotine replacement versus nicotine replacement after flap is challenging. Electronic cigarettes should be discouraged as a means of NRT.

Anesthesiologists and the Other Pandemic: Tobacco Use

Tobacco use will kill a projected 1 billion people in the 21st century in one of the deadliest pandemics in history. Tobacco use disorder is a disease with a natural history, pathophysiology, and effective treatment options. Anesthesiologists can play a unique role in fighting this pandemic, providing both immediate (reduction in perioperative risk) and long-term (reduction in tobacco-related diseases) benefits to their patients who are its victims. Receiving surgery is one of the most powerful stimuli to quit tobacco. Tobacco treatments that combine counseling and pharmacotherapy (e.g., nicotine replacement therapy) can further increase quit rates and reduce risk of morbidity such as pulmonary and wound-related complications. The perioperative setting provides a great opportunity to implement multimodal perianesthesia tobacco treatment, which combines multiple evidence-based tactics to implement the four core components of consistent ascertainment and documentation of tobacco use, advice to quit, access to pharmacotherapy, and referral to counseling resources.

Human skin responses to environmental pollutants: A review of current scientific models

Whatever the exposure route, chemical, physical and biological pollutants modify the whole organism response, leading to nerve, cardiac, respiratory, reproductive, and skin system pathologies. Skin acts as a barrier for preventing pollutant modifications. This review aims to present the available scientific models, which help investigate the impact of pollution on the skin. The research question was "Which experimental models illustrate the impact of pollution on the skin in humans?" The review covered a period of 10 years following a PECO statement on in vitro, ex vivo, in vivo and in silico models. Of 582 retrieved articles, 118 articles were eligible. In oral and inhalation routes, dermal exposure had an important impact at both local and systemic levels. Healthy skin models included primary cells, cell lines, co-cultures, reconstructed human epidermis, and skin explants. In silico models estimated skin exposure and permeability. All pollutants affected the skin by altering elasticity, thickness, the structure of epidermal barrier strength, and dermal extracellular integrity. Some specific models concerned wound healing or the skin aging process. Underlying mechanisms were an exacerbated inflammatory skin reaction with the modulation of several cytokines and oxidative stress responses, ending with apoptosis. Pathological skin models revealed the consequences of environmental pollutants on psoriasis, atopic dermatitis, and tumour development. Finally, scientific models were used for evaluating the safety and efficacy of potential skin formulations in preventing the skin aging process or skin irritation after repeated contact. The review gives an overview of scientific skin models used to assess the effects of pollutants. Chemical and physical pollutants were mainly represented while biological contaminants were little studied. In future developments, cell hypoxia and microbiota models may be considered as more representative of clinical situations. Models considering humidity and temperature variations may reflect the impact of these changes.

Smoking increases the risk of postoperative wound complications: A propensity score-matched cohort study

Cigarette smoking is associated with surgical complications, including wound healing and surgical site infection. However, the association between smoking status and postoperative wound complications is not completely understood. Our objective was to investigate the effect of smoking on postoperative wound complications for major surgeries. Data were collected from the 2013 to 2018 participant use files of the American College of Surgeons National Surgical Quality Improvement Program database. A propensity score matching procedure was used to create the balanced smoker and nonsmoker groups. Multivariable logistic regression was used to calculate the odds ratios (ORs) with 95% confidence intervals (CIs) for postoperative wound complications, pulmonary complications, and in-hospital mortality associated with smokers. A total of 1 156 002 patients (578 001 smokers and 578 001 nonsmokers) were included in the propensity score matching analysis. Smoking was associated with a significantly increased risk of postoperative wound disruption (OR 1.65, 95% CI 1.56-1.75), surgical site infection (OR 1.31, 95% CI 1.28-1.34), reintubation (OR 1.47, 95% CI 1.40-1.54), and in-hospital mortality (OR 1.13, 95% CI 1.07-1.19) compared with nonsmoking. The length of hospital stay was significantly increased in smokers compared with nonsmokers. Our analysis indicates that smoking is associated with an increased risk of surgical site infection, wound disruption, and postoperative pulmonary complications. The results may drive the clinicians to encourage patients to quit smoking before surgery.

Difference of body surface temperature in stable chronic obstructive pulmonary disease patients with different degree of airflow limitation

BACKGROUND

This study aimed to investigate the changes of body surface temperature of stable chronic obstructive pulmonary disease (COPD) patients and explore its clinical significance for the progression of COPD.

OBJECTIVES

The aim of this study was to explore the correlation between body surface temperature and disease severity in COPD patients.

METHODS

From May 2015 to May 2016, the patients who were diagnosed as COPD at stable phase (n = 148) were enrolled in this study. The subjects in control group (n = 49) were healthy people. The patients' general condition modified Medical Research Council (mMRC) dyspnea scale and the COPD assessment test (CAT) score were recorded, and pulmonary function of patients was determined. Back average temperature measurement was made using a thermal infrared imager (DT-9875, CEM, China).

RESULTS

Patients in the COPD group had significantly lower mean temperatures of the back than those in the control group. The mean temperature of the back presented a decreased tendency with the aggravation of airflow limitation. Correlation analysis revealed that in the COPD group, the back temperature was negatively correlated with smoking index and mMRC score. FEV1%, FVC% and FEV1/FVC were positively correlated with pulmonary function. Smoking showed a tendency to lower the back temperature of COPD patients.

CONCLUSIONS

This study preliminarily suggested that the body surface temperature of COPD patients decreased compared with that of healthy people, which may be associated with the dysfunction of autonomic nerve, increased basal metabolic rate, metabolic syndrome and peripheral nerve injury in COPD patients.

The Orthopedic Effects of Electronic Cigarettes: A Systematic Review and Pediatric Case Series

Electronic cigarette (EC) use is highly prevalent, especially in the adolescent population, where 29% of Canadian adolescents have used an EC in the past thirty days per national surveys. Our pediatric orthopedic referral centre observed a cluster of delayed unions of bone fractures in adolescents using ECs and present the case series here. We then asked whether electronic cigarettes impair bone healing or influence orthopedic outcomes. A PRISMA-compliant systematic review was carried out, which revealed no human clinical studies and a general paucity of evidence around ECs and musculoskeletal health. The existing experimental evidence relevant to orthopedics is summarized. The effect of ECs on the musculoskeletal system is poorly understood and is a target for further research.

Implications of Electronic Cigarettes on the Safe Administration of Sedation and General Anesthesia in the Outpatient Dental Setting

Today the number of electronic cigarette users continues to rise as electronic cigarettes slowly, yet steadily overtake conventional cigarettes in popularity. This shift is often attributed to the misconception that electronic cigarettes are "safer" or "less dangerous" than conventional cigarettes. Recent studies have shown that electronic cigarettes are far from safe and that the inhaled agents and byproducts within vaping aerosols can have adverse effects on systemic and oral health like combustible tobacco products. The first electronic cigarettes were originally introduced as a tool for smoking cessation. However, newer iterations of electronic cigarette devices have been modified to allow the user to consume tetrahydrocannabinol (THC), the psychoactive component of cannabis, in addition to nicotine. As the popularity of these devices continues to rise, the number of patients seeking dental treatment who also consume electronic cigarettes will too. This article aims to shed light on the deleterious effects electronic cigarettes can have on systemic and oral health, as well as the special considerations for sedation and anesthesia providers treating patients who use electronic cigarettes.

The influence of smoking and alcohol on bone healing: Systematic review and meta-analysis of non-pathological fractures

BACKGROUND

We aimed to comprehensively evaluate the associations between (i) smoking, (ii) preoperative smoking cessation time, (iii) nicotine replacement therapy (NRT), (iv) vaping, and (v) alcohol consumption and non-pathological fracture healing in adult patients. We also assessed the impacts of preoperative smoking cessation time, NRT, and vaping on wound healing and wound complications after any sort of surgery.

METHODS

We searched the MEDLINE, Embase, Cochrane CENTRAL, CINAHL, and AMED electronic databases from their inceptions until August 9th, 2021. Primary outcomes included delayed union rate, nonunion rate, and time to union. A random effects model was used. (Protocol registration: PROSPERO-CRD42019131454).

FINDINGS

One hundred and twenty-two studies with 417,767 patients were eligible for the systematic review and 71 of the studies with 39,920 patients were eligible for the meta-analysis. After non-pathological fracture treatment, the nonunion rate was significantly greater in the smoker group than in the non-smoker group (odds ratio [OR], 2·50, 95% confidence interval [1·73-3·61]); additionally, there was no significant difference in the nonunion rate (OR, 0·97 [0·40-2·38]) between the alcohol drinker group and the non-drinker group. The rate of wound infection after surgery was significantly reduced in the smoking cessation group (≥four weeks before surgery) compared to the continuous smoker group (OR, 0·37 [0·16-0·89]).

INTERPRETATION

Smoking is associated with higher rates of nonunion and deep surgical site infection after non-pathological fracture treatment. Smoking cessation (≥four weeks before surgery) is associated with a decreased rate of postoperative wound infection.

FUNDING

The China Scholarship Council (no. 201809120013).

Nicotine Exposure Via Electronic Cigarettes Significantly Impedes Biomechanical Healing Properties of Tendon Healing in a Rat Model

PURPOSE

To evaluate the biomechanical and histologic effects on Achilles tendon repair of inhaled combusted tobacco versus nicotine exposure via electronic cigarette versus a control group in a small-animal model (Sprague-Dawley rat).

METHODS

Fifty-four Sprague-Dawley rats were randomized into 3 groups: combusted tobacco, e-cigarettes, or control. Experimental rats were exposed to research cigarettes or e-cigarette vapor in a smoking chamber for 4 weeks. Surgical transection and repair of the Achilles tendon were then completed, followed by 2 additional weeks of exposure. Achilles tendons were harvested, and biomechanical tensile testing was performed. Histologic evaluation was completed, including hematoxylin-eosin staining, trichrome staining, and immunohistochemistry analysis for type I and type III collagen.

RESULTS

The control group showed the highest mean tensile load to failure, at 41.0 ± 10.4 N (range, 18.3-55.1 N); the cigarette cohort had the second highest mean, at 37.3 ± 11.1 N (range, 14.0-54.7 N); and finally, the vaping group had the lowest mean, at 32.3 ± 8.4 N (range, 17.8-45.1 N). One-way analysis of variance showed a significant difference in load to failure when comparing the control group with the e-cigarette group (P = .026). No statistical difference was detected between the control group and cigarette group (P = .35) or between the e-cigarette group and cigarette group (P = .23). Stiffness and qualitative histologic analysis showed no difference among groups.

CONCLUSIONS

This investigation shows that in a rat model, nicotine exposure via e-cigarette significantly impedes the biomechanical healing properties of Achilles tendon surgical repair.

CLINICAL RELEVANCE

The results indicate that although e-cigarettes are often used as a perceived "safer" alternative to smoking, their use may have a detrimental effect on tendon load to failure.

Substance Addiction and the Hand Surgery Patient: A Comprehensive Review

Substance abuse is pervasive in the American society, with 10% of the United States population using marijuana, up to 17% of patients undergoing upper-extremity surgery reporting chronic opioid use, and up to 20% of acute hand infections occurring secondary to intravenous drug use. It is common, therefore, for a hand surgeon to take care of a patient under the influence of nonprescription drugs. The range of abused substances is diverse, and the implications are profound. As such, it is important for hand surgeons to understand the potential implications of drug use to best guide patient care and surgical decision-making. The abuse of opioids, amphetamines, marijuana, and other substances has an impact on treatment timing, adherence to postoperative hand therapy, and/or clinic follow ups. The physiologic effects of these drugs affect surgical risk, wound healing, and bone healing. Social factors associated with drug abuse can complicate the management of these patients. Collectively, all these factors substantially affect surgical outcomes. In this review, we provide an overview of commonly abused illicit and prescription drugs seen in hand surgery practice, tips to identify substance abuse, the drugs' implications for surgical risks, outcomes, and some recommendations for management.

Effects of tobacco and vaping on the skin

Cigarette and electronic cigarette use are significant public health concerns across the United States. Tobacco use remains the single most preventable cause of morbidity and mortality in the world. Electronic cigarettes initially emerged as a better alternative to conventional cigarettes and for promoting smoking cessation; however, current evidence reveals similar deleterious health implications caused by both products on almost all organ systems, including the skin. Recognition of the cutaneous manifestations associated with cigarette and electronic cigarette use is essential for dermatologists in current clinical practice. Dermatologists play a vital role in educating and counseling patients on smoking cessation. We specifically highlight the cutaneous consequences of conventional cigarette smoking and electronic cigarettes on dermatologic disease.

Are electronic cigarettes and vaping effective tools for smoking cessation? Limited evidence on surgical outcomes: a narrative review

The rising popularity of e-cigarettes and vaping, particularly in youth populations, has prompted the scientific community to ocassionally recommend their use as alternative to smoking or as a modality for smoking cessation. Media also tends to portray them as stylish, smoking cessation tools. We first studied the current literature to better understand whether they are viable options for surgeons to use prior to surgery as part of their armamentarium and their efficacy in attaining smoking abstinence. Next, we performed a comprehensive review of the literature to study the impact of e-cigarette and vaping on lung pathophysiology, surgical outcomes, and postoperative complications. After a thorough search, we found limited evidence suggesting that e-cigarettes and vaping are effective smoking cessation tools, and indeed may increase the propensity of dual smoking, contrary to e-cigarette advertisements. Many potential biases and limitations exist due to self-reporting when investigating e-cigarettes and vaping. While there is controversial data in the literature about e-cigarettes and vaping not leading to lung cancer, there are chemicals in these products that compromise lung hemostasis, negatively affect the immune system, and have detrimental inflammatory effects on wound healing. Studies are warranted to elucidate objective data regarding short and long-term effects of these products on surgical outcomes, and given the current data, they should not be utilized as viable smoking cessation tools.

Current Perspectives on Characteristics, Compositions, and Toxicological Effects of E-Cigarettes Containing Tobacco and Menthol/Mint Flavors

Electronic nicotine delivery systems/devices (ENDS) such as electronic cigarettes (e-cigarettes) have been made available globally, with the intent to reduce tobacco smoking. To make these products more appealing to young adults, many brands have added flavoring agents. However, these flavoring agents are shown to progressively result in lung toxicity when inhaled via e-cigarettes. While recent federal regulations have banned the sale of flavored e-cigarettes other than tobacco or menthol flavors, concerns have been raised about the health effects of even these flavors. In this review, we evaluate the current toxicological data with regard to effects upon exposure in animal models and in vitro cell culture for these popular flavorants. We have tabulated the current e-cigarette products containing these most common flavors (menthol, mint, and tobacco) in the market. We have also indicated the prevalence of tobacco and menthol-flavor use among e-cigarette users and highlighted the possible challenges and benefits that will result from new federal regulations.

How bad are e-cigarettes? What can we learn from animal exposure models?

Electronic cigarettes divide opinions. Some consider them key to reducing smoking incidence while others are concerned over potential for detrimental health consequences. It will take many years to identify the health consequences of e-cigarette use if we rely only upon human data. However, there is a growing body of work using rodent models that inform on these potential toxicities. These studies have focused upon the pulmonary, cardiovascular and central nervous systems. Observations include perturbations of pro-inflammatory, pro-fibrotic and oxidative stress markers, sometimes together with DNA damage and downregulation of DNA repair and antioxidant enzymes. However, the markers affected are often different between studies. A more consistent observation has been the increase in airway hyperresponsiveness, a characteristic of asthma, on exposure to electronic cigarettes, across mouse strains, sex and ages. Detrimental effects in this and other susceptible animal models such as the apolipoprotein E knock-out mouse model of atherosclerosis, suggest greater risk where there is an existing predisposition. Other adverse reactions, including weight loss, oxidative stress and angiogenesis, are reported in animal studies with nicotine-containing devices. These effects remain less severe than cigarette smoke, where investigated. Animal studies have identified therefore that e-cigarettes are potentially hazardous, especially in susceptible populations, nicotine is integral to risk of health effects, but overall e-cigarettes are much less hazardous than cigarettes.

A Summary of In Vitro and In Vivo Studies Evaluating the Impact of E-Cigarette Exposure on Living Organisms and the Environment

Worldwide use of electronic cigarettes has been rapidly expanding over recent years, but the long-term effect of e-cigarette vapor exposure on human health and environment is not well established; however, its mechanism of action entails the production of reactive oxygen species and trace metals, and the exacerbation of inflammation, which are associated with potential cytotoxicity and genotoxicity. The present study examines the effects of selected liquid chemicals used in e-cigarettes, such as propylene glycol/vegetable glycerin, nicotine and flavorings, on living organisms; the data collected indicates that exposure to e-cigarette liquid has potentially detrimental effects on cells in vitro, and on animals and humans in vivo. While e-liquid exposure can adversely influence the physiology of living organisms, vaping is recommended as an alternative for tobacco smoking. The study also compares the impact of e-cigarette liquid exposure and traditional cigarette smoke on organisms and the environmental impact. The environmental influence of e-cigarette use is closely connected with the emission of airborne particulate matter, suggesting the possibility of passive smoking. The obtained data provides an insight into the impact of nicotine delivery systems on living organisms and the environment.

The role of DJ-1 in human primary alveolar type II cell injury induced by e-cigarette aerosol

The alveolus participates in gas exchange, which can be impaired by environmental factors and toxins. There is an increase in using electronic cigarettes (e-cigarettes); however, their effect on human primary alveolar epithelial cells is unknown. Human lungs were obtained from nonsmoker organ donors to isolate alveolar type II (ATII) cells. ATII cells produce and secrete pulmonary surfactant and restore the epithelium after damage, and mitochondrial function is important for their metabolism. Our data indicate that human ATII cell exposure to e-cigarette aerosol increased IL-8 levels and induced DNA damage and apoptosis. We also studied the cytoprotective effect of DJ-1 against ATII cell injury. DJ-1 knockdown in human primary ATII cells sensitized cells to mitochondrial dysfunction as detected by high mitochondrial superoxide production, decreased mitochondrial membrane potential, and calcium elevation. DJ-1 knockout (KO) mice were more susceptible to ATII cell apoptosis and lung injury induced by e-cigarette aerosol compared with wild-type mice. Regulation of the oxidative phosphorylation (OXPHOS) is important for mitochondrial function and protection against oxidative stress. Major subunits of the OXPHOS system are encoded by both nuclear and mitochondrial DNA. We found dysregulation of OXPHOS complexes in DJ-1 KO mice after exposure to e-cigarette aerosol, which could disrupt the nuclear/mitochondrial stoichiometry, resulting in mitochondrial dysfunction. Together, our results indicate that DJ-1 deficiency sensitizes ATII cells to damage induced by e-cigarette aerosol leading to lung injury.

Can Nicotine Replacement Therapy Decrease Complications in Plastic Surgery?

Cigarette smoking has been well demonstrated to be associated with adverse outcomes and increased complications in surgical patients in the operative and postoperative periods. There is general agreement that smoking cessation decreases such risks; however, much debate still exists regarding the most effective modalities for risk mitigation, especially concerning modalities involving nicotine replacement in some form. This article reviews the discussion regarding smoking cessation therapies, in particular those involving nicotine replacement, in the context of mitigating risk in plastic surgery procedures. The recent rise in popularity of electronic cigarettes poses further challenges for clinicians in minimizing risk and optimizing outcomes for patients. Prospective studies including high-level evidence such as randomized controlled clinical trials will be required to help plastic surgeons develop guidelines that will enable optimization of patient safety and clinical outcomes.

Effects of nicotine and THC vapor inhalation administered by an electronic nicotine delivery system (ENDS) in male rats

BACKGROUND

Electronic nicotine delivery systems (ENDS, e-cigarettes) are increasingly used for the self-administration of nicotine by various human populations, including previously nonsmoking adolescents. Studies in preclinical models are necessary to evaluate health impacts of ENDS including the development of nicotine addiction, effects of ENDS vehicles, flavorants and co-administered psychoactive substances such as Δ⁹-tetrahydrocannabinol (THC). This study was conducted to validate a rat model useful for the study of nicotine effects delivered by inhalation of vapor created by ENDS.

METHODS

Male Sprague-Dawley rats (N = 8) were prepared with radio telemetry devices for the reporting of temperature and activity. Experiments subjected rats to inhalation of vapor generated by an electronic nicotine delivery system (ENDS) adapted for rodents. Inhalation conditions included vapor generated by the propylene glycol (PG) vehicle, Nicotine (1, 10, 30 mg/mL in the PG) and THC (12.5, 25 mg/mL).

RESULTS

Nicotine inhalation increased spontaneous locomotion and decreased body temperature of rats. Pretreatment with the nicotinic cholinergic receptor antagonist mecamylamine (2 mg/kg, i.p.) prevented stimulant effects of nicotine vapor inhalation and attenuated the hypothermic response. Combined inhalation of nicotine and THC resulted in apparently independent effects which were either additive (hypothermia) or opposed (activity).

CONCLUSIONS

These studies provide evidence that ENDS delivery of nicotine via inhalation results in nicotine-typical effects on spontaneous locomotion and thermoregulation in male rats. Effects were blocked by a nicotinic antagonist, demonstrating mechanistic specificity. This system will therefore support additional studies of the contribution of atomizer/wick design, vehicle constituents and/or flavorants to the effects of nicotine administered by ENDS.

Electronic cigarettes: a task force report from the European Respiratory Society

There is a marked increase in the development and use of electronic nicotine delivery systems or electronic cigarettes (ECIGs). This statement covers electronic cigarettes (ECIGs), defined as "electrical devices that generate an aerosol from a liquid" and thus excludes devices that contain tobacco. Database searches identified published articles that were used to summarise the current knowledge on the epidemiology of ECIG use; their ingredients and accompanied health effects; second-hand exposure; use of ECIGs for smoking cessation; behavioural aspects of ECIGs and social impact; in vitro and animal studies; and user perspectives.ECIG aerosol contains potentially toxic chemicals. As compared to conventional cigarettes, these are fewer and generally in lower concentrations. Second-hand exposures to ECIG chemicals may represent a potential risk, especially to vulnerable populations. There is not enough scientific evidence to support ECIGs as an aid to smoking cessation due to a lack of controlled trials, including those that compare ECIGs with licenced stop-smoking treatments. So far, there are conflicting data that use of ECIGs results in a renormalisation of smoking behaviour or for the gateway hypothesis. Experiments in cell cultures and animal studies show that ECIGs can have multiple negative effects. The long-term effects of ECIG use are unknown, and there is therefore no evidence that ECIGs are safer than tobacco in the long term. Based on current knowledge, negative health effects cannot be ruled out.