Chemical Emissions From Heated Vitamin E Acetate—Insights to Respiratory Risks From Electronic Cigarette Liquid Oil Diluents Used in the Aerosolization of Δ9-THC-Containing Products

Multidisciplinary approaches in electronic nicotine delivery systems pulmonary toxicology: emergence of living and non-living bioinspired engineered systems

Technology-based platforms offer crucial support for regulatory agencies in overseeing tobacco products to enhance public health protection. The use of electronic nicotine delivery systems (ENDS), such as electronic cigarettes, has surged exponentially over the past decade. However, the understanding of the impact of ENDS on lung health remains incomplete due to scarcity of physiologically relevant technologies for evaluating their toxicity. This review examines the societal and public health impacts of ENDS, prevalent preclinical approaches in pulmonary space, and the application of emerging Organ-on-Chip technologies and bioinspired robotics for assessing ENDS respiratory toxicity. It highlights challenges in ENDS inhalation toxicology and the value of multidisciplinary bioengineering approaches for generating reliable, human-relevant regulatory data at an accelerated pace.

The role of puff volume in vaping emissions, inhalation risks, and metabolic perturbations: a pilot study

Secondhand vaping exposure is an emerging public health concern that remains understudied. In this study, saliva and exhaled emissions from ENDS users (secondhand) and non-ENDS users (baseline) were collected, firsthand emissions were generated using an automated ENDS aerosol generation system programmed to simulate puffing topography profiles collected from ENDS users. Particulate concentrations and sizes along with volatile organic compounds were characterized. We revealed puffing topography metrics as potential mediators of firsthand and secondhand particle and chemical exposures, as well as metabolic and respiratory health outcomes. Particle deposition modeling revealed that while secondhand emissions displayed smaller deposited mass, total and pulmonary particle deposition fractions were higher than firsthand deposition levels, possibly due to smaller secondhand emission particle diameters. Lastly, untargeted metabolomic profiling of salivary biomarkers of lung injury due to firsthand ENDS exposures revealed potential early indicators of respiratory distress that may also be relevant in bystanders exposed to secondhand vaping scenarios. By leveraging system toxicology, we identified 10 metabolites, including leukotriene D4, that could potentially serve as biomarkers for ENDS use, exposure estimation, and the prediction of vaping-related disease. This study highlights characterization of vaping behavior is an important exposure component in advancing our understanding of potential health effects in ENDS users and bystanders.

Nicotine or marijuana vaping exposure during pregnancy and altered immune responses in offspring

Electronic nicotine delivery systems (ENDS) - which include electronic cigarettes or e-cigarettes, or simply e-cigs, and marijuana vaping have become increasingly popular. ENDS devices have been established as one of the tobacco quit methods and promoted to be safer compared to traditional tobacco cigarettes. Emerging evidence demonstrates that e-cigarette and marijuana vape use can be harmful, with potential associations with cancer. Herein, we summarize the level of evidence to date for altered immune response, with a focus on cancer risks in the offspring after maternal use of, or aerosol exposures from, ENDS or marijuana vape during pregnancy. From 27 published articles retrieved from PubMed, we sought to find out identified carcinogens in ENDS aerosols and marijuana vapor, which cross the placental barrier and can increase cancer risk in the offspring. Carcinogens in vaping aerosols include aldehydes, metals, tobacco-specific nitrosamines, tobacco alkaloids, polycyclic aromatic hydrocarbons, and volatile organic compounds. Additionally, there was only one passive vaping exposure case study on a human fetus, which noted that glycerol, aluminum, chromium, nickel, copper, zinc, selenium, and lead crossed from the mother to the offspring's cord blood. The carcinogens (metals) in that study were at lower concentrations compared to the mother's biological matrices. Lastly, we observed that in utero exposures to ENDS-associated chemicals can occur in vital organs such as the lungs, kidneys, brain, bladder, and heart. Any resulting DNA damage increases the risk of tumorigenesis. Future epidemiological studies are needed to examine the effects of passive aerosol exposures from existing and emerging electronic nicotine and marijuana products on developing offspring to cancer.

The E-cigarette or Vaping Product Use-Associated Lung Injury Epidemic: Pathogenesis, Management, and Future Directions: An Official American Thoracic Society Workshop Report

E-cigarette or vaping product use-associated lung injury (EVALI) is a severe pulmonary illness associated with the use of e-cigarettes or vaping products that was officially identified and named in 2019. This American Thoracic Society workshop was convened in 2021 to identify and prioritize research and regulatory needs to adequately respond to the EVALI outbreak and to prevent similar instances of disease associated with e-cigarette or vaping product use. An interdisciplinary group of 26 experts in adult and pediatric clinical care, public health, regulatory oversight, and toxicology were convened for the workshop. Four major topics were examined: 1) the public health and regulatory response to EVALI; 2) EVALI clinical care; 3) mechanisms contributing to EVALI; and 4) needed actions to address the health effects of EVALI. Oral presentations and group discussion were the primary modes used to identify top priorities for addressing EVALI. Initiatives including a national EVALI case registry and biorepository, integrated electronic medical record coding system, U.S. Food and Drug Administration regulation and enforcement of nicotine e-cigarette standards, regulatory authority over nontobacco-derived e-cigarettes, training in evaluating exogenous exposures, prospective clinical studies, standardized clinical follow-up assessments, ability to more readily study effects of cannabinoid e-cigarettes, and research to identify biomarkers of exposure and disease were identified as critical needs. These initiatives will require substantial federal investment as well as changes to regulatory policy. Overall, the workshop identified the need to address the root causes of EVALI to prevent future outbreaks. An integrated approach from multiple perspectives is required, including public health; clinical, basic, and translational research; regulators; and users of e-cigarettes. Improving the public health response to reduce the risk of another substantial disease-inducing event depends on coordinated actions to better understand the inhalational toxicity of these products, informing the public of the risks, and developing and enforcing regulatory standards for all e-cigarettes.

Vaping Aerosols from Vitamin E Acetate and Tetrahydrocannabinol Oil: Chemistry and Composition

The popularity of vaping cannabis products has increased sharply in recent years. In 2019, a sudden onset of electronic cigarette/vaping-associated lung injury (EVALI) was reported, leading to thousands of cases of lung illness and dozens of deaths due to the vaping of tetrahydrocannabinol (THC)-containing e-liquids that were obtained on the black market. A potential cause of EVALI has been hypothesized due to the illicit use of vitamin E acetate (VEA) in cannabis vape cartridges. However, the chemistry that modifies VEA and THC oil, to potentially produce toxic byproducts, is not well understood under different scenarios of use. In this work, we quantified carbonyls, organic acids, cannabinoids, and terpenes in the vaping aerosol of pure VEA, purified THC oil, and an equal volume mixture of VEA and THC oil at various coil temperatures (100-300 °C). It was found under the conditions of our study that degradation of VEA and cannabinoids, including Δ⁹-THC and cannabigerol (CBG), occurred via radical oxidation and direct thermal decomposition pathways. Evidence of terpene degradation was also observed. The bond cleavage of aliphatic side chains in both VEA and cannabinoids formed a variety of smaller carbonyls. Oxidation at the ring positions of cannabinoids formed various functionalized products. We show that THC oil has a stronger tendency to aerosolize and degrade compared to VEA at a given temperature. The addition of VEA to the e-liquid nonlinearly suppressed the formation of vape aerosol compared to THC oil. At the same time, toxic carbonyls including formaldehyde, 4-methylpentanal, glyoxal, or diacetyl and its isomers were highly enhanced in VEA e-liquid when normalized to particle mass.

Temperature dependence of emission product distribution from vaping of vitamin E acetate

Nearly two years after vitamin E acetate (VEA) was identified as the potential cause of the 2019–2020 outbreak of e-cigarette, or vaping product-associated lung injuries (EVALI), the toxicity mechanisms of VEA vaping are still yet to be fully understood. Studies since the outbreak have found that e-liquids such as VEA undergo thermal degradation during the vaping process to produce various degradation products, which may pose a greater risk of toxicity than exposure to unvaped VEA. Additionally, a wide range of customizable parameters–including the model of e-cigarette used, puffing topography, or the applied power/temperature used to generate aerosols–have been found to influence the physical properties and chemical compositions of vaping emissions. However, the impact of heating coil temperature on the chemical composition of VEA vaping emissions has not been fully assessed. In this study, we investigated the emission product distribution of VEA vaping emissions produced at temperatures ranging from 176 to 356°C, corresponding to a variable voltage vape pen set at 3.3 to 4.8V. VEA degradation was found to be greatly enhanced with increasing temperature, resulting in a shift towards the production of lower molecular weight compounds, such as the redox active duroquinone (DQ) and short-chain alkenes. Low temperature vaping of VEA resulted in the production of long-chain molecules, such as phytol, exposure to which has been suggested to induce lung damage in previous studies. Furthermore, differential product distribution was observed in VEA degradation products generated from vaping and from pyrolysis using a tube furnace in the absence of the heating coil at equivalent temperatures, suggesting the presence of external factors such as metals or oxidation that may enhance VEA degradation during vaping. Overall, our findings indicate that vaping behavior may significantly impact the risk of exposure to toxic vaping products and potential for vaping-related health concerns.