The fog, the attractive and the addictive: pulmonary effects of vaping with a focus on the contribution of each major vaping liquid constituent

[Medical societies in Germany call for a ban on flavors in e-cigarettes - A Position Paper of the German Respiratory Society (DGP) in cooperation with other professional associations and organizations]

E-cigarettes are primarily used by teenagers and young adults. Flavors in e-cigarettes increase their attractiveness and encourage young people and adults to start using them. This exposes young people in particular to the risk of nicotine addiction and various toxic substances from the aerosol of e-cigarettes. There are indications that various flavors in e-cigarettes are harmful to health, although toxicological studies are still lacking for the majority of flavors. There is a need for independent scientific investigations in this area. The scientific societies involved are calling for a ban on flavors in e-cigarettes, a ban on disposable e-cigarettes, effective regulation of the sale of e-cigarettes and effective control and implementation of the provisions for the protection of minors.

Detection of vaping, cannabis use, and hazardous prescription opioid use among adolescents

There has been a global surge in adolescents' use of electronic nicotine delivery systems (vaping), cannabis (vaped and edible), and prescription opioids, collectively termed ECPO. The nature of ECPO use can make it difficult to detect due to few obvious immediate physical and behavioural signs, as well as subtle long-term effects that allow adolescents to transition from initial exploration into hazardous ECPO use without easy detection by care providers. Here, we address the nature of the presentation of ECPO use in adolescents (roughly age 13-18 years), including challenges in detecting use and related complications, which affect screening, prevention, and intervention. We begin by reviewing empirical data on these difficult to detect effects in adolescents, including acute effects at cellular and neural levels and long-term neurocognitive and developmental changes that precede outwardly detectable physical signs. We then provide concrete approaches for providers to screen for ECPO use in adolescents even in the absence of overt physical and behavioural symptoms. Finally, we conclude with direct practice recommendations for prevention and intervention.

Menthol in Electronic Cigarettes Causes Biophysical Inhibition of Pulmonary Surfactant

With an increasing prevalence of electronic cigarette (e-cigarette) use, especially among youth, there is an urgent need to better understand the biological risks and pathophysiology of health conditions related to e-cigarettes. A majority of e-cigarette aerosols are in the submicron size and would deposit in the alveolar region of the lung, where they must first interact with the endogenous pulmonary surfactant. To date, little is known whether e-cigarette aerosols have an adverse impact on the pulmonary surfactant. We have systematically studied the effect of individual e-cigarette ingredients on an animal-derived clinical surfactant preparation, bovine lipid extract surfactant, using a combination of biophysical and analytical techniques, including in vitro biophysical simulations using constrained drop surfactometry, molecular imaging with atomic force microscopy, chemical assays using carbon nuclear magnetic resonance and circular dichroism, and in silico molecular dynamics simulations. All data collectively suggest that flavorings used in e-cigarettes, especially menthol, play a predominant role in inhibiting the biophysical function of the surfactant. The mechanism of biophysical inhibition appears to involve menthol interactions with both phospholipids and hydrophobic proteins of the natural surfactant. These results provide novel insights into the understanding of the health impact of e-cigarettes and may contribute to a better regulation of e-cigarette products.

Glycerol contained in vaping liquids affects the liver and aspects of energy homeostasis in a sex-dependent manner

Vaping is increasingly popular among the young and adult population. Vaping liquids contained in electronic cigarettes (e-cigarettes) are mainly composed of propylene glycol and glycerol, to which nicotine and flavors are added. Among several biological processes, glycerol is a metabolic substrate used for lipid synthesis in fed state as well as glucose synthesis in fasting state. We aimed to investigate the effects of glycerol e-cigarette aerosol exposure on the aspects of glycerol and glucose homeostasis. Adult and young male and female mice were exposed to e-cigarette aerosols with glycerol as vaping liquid using an established whole-body exposure system. Mice were exposed acutely (single 2-h exposure) or chronically (2 h/day, 5 days/week for 9 weeks). Circulating glycerol and glucose levels were assessed and glycerol as well as glucose tolerance tests were performed. The liver was also investigated to assess changes in the histology, lipid content, inflammation, and stress markers. Lung functions were also assessed as well as hepatic mRNA expression of genes controlling the circadian rhythm. Acute exposure to glycerol aerosols generated by an e-cigarette increased circulating glycerol levels in female mice. Increased hepatic triglyceride and phosphatidylcholine concentrations were observed in female mice with no increase in circulating alanine aminotransferase or evidence of inflammation, fibrosis, or endoplasmic reticulum stress. Chronic exposure to glycerol e-cigarette aerosols mildly impacted glucose tolerance test in young female and male mice. Fasting glycerol, glucose, and insulin remained unchanged. Increased pulmonary resistance was observed in young male mice. Taken together, this study shows that the glycerol contained in vaping liquids can affect the liver as well as the aspects of glucose and glycerol homeostasis. Additional work is required to translate these observations to humans and determine the biological and potential pathological impacts of these findings.

VAPIng into ARDS: Acute Respiratory Distress Syndrome and Cardiopulmonary Failure

"Modern" vaping involving battery-operated electronic devices began approximately one dozen years and has quickly evolved into a multibillion dollar industry providing products to an estimated 50 million users worldwide. Originally developed as an alternative to traditional cigarette smoking, vaping now appeals to a diverse demographic including substantial involvement of young people who often have never used cigarettes. The rapid rise of vaping fueled by multiple factors has understandably outpaced understanding of biological effects, made even more challenging due to wide ranging individual user habits and preferences. Consequently while vaping-related research gathers momentum, vaping-associated pathological injury (VAPI) has been established by clinical case reports with severe cases manifesting as acute respiratory distress syndrome (ARDS) with examples of right ventricular cardiac failure. Therefore, basic scientific studies are desperately needed to understand the impact of vaping upon the lungs as well as cardiopulmonary structure and function. Experimental models that capture fundamental characteristics of vaping-induced ARDS are essential to study pathogenesis and formulate recommendations to mitigate harmful effects attributable to ingredients or equipment. So too, treatment strategies to promote recovery from vaping-associated damage require development and testing at the preclinical level. This review summarizes the back story of vaping leading to present day conundrums with particular emphasis upon VAPI-associated ARDS and prioritization of research goals.