Another Warning Sign: High Nicotine Content in Electronic Cigarettes Disrupts Mucociliary Clearance, the Essential Defense Mechanism of the Lung

Effect of Electronic Cigarette Vapour Exposure on Ca2+- and cAMP-Dependent Ion Transport in Human Airway Epithelial Cells

PURPOSE

The popularity of electronic cigarettes (e-cigarettes) has grown exponentially over the past few years, and teenagers now prefer them to tobacco cigarettes. We determined whether exposure to e-cigarette vapour (e-vapour) adversely affects ion transport using human airway epithelial cell lines 16HBE14o- and Calu-3 and well-differentiated primary human bronchial epithelial cells (HBEs).

METHODS

We concurrently measured fluorescent signals and short-circuit current (ISC), an indicator of electrogenic ion transport, in polarised epithelia. The P2Y receptor-mediated signalling pathway was used to induce an increase in intracellular calcium concentration ([Ca2+]i) and ISC. We used a single-polypeptide fluorescence resonance energy transfer reporter based on exchange proteins directly activated by cAMP (Epac) to measure forskolin-induced changes in cAMP and ISC.

RESULTS

We compared the effects of e-vapour to those of traditional cigarette smoke (CS) on the human airway cell models. In all three cell types, e-vapour, similar to CS, significantly reduced agonist-induced increases in Ca2+ or cAMP signalling and ISC. However, reductions in the epithelial electrolyte transport activities did not correlate with any changes in the protein levels of various ion channels and transporters.

CONCLUSION

Our data suggest that e-vapour is not harmless and causes ion transport dysfunction similar to CS, thereby predisposing e-cigarette users to vaping-induced lung injury.

Downregulation of Stem-Loop Binding Protein by Nicotine via α7-Nicotinic Acetylcholine Receptor and Its Role in Nicotine-Induced Cell Transformation

The use of electronic-cigarettes (e-cigs) has increased substantially in recent years, particularly among the younger generations. Liquid nicotine is the main component of e-cigs. Previous studies have shown that mice exposed to e-cig aerosols developed lung adenocarcinoma and bladder hyperplasia. These findings implicated a potential role for e-cig aerosols and nicotine in cancer development, although the underlying mechanisms are not fully understood. Here we report that exposure to liquid nicotine or nicotine aerosol generated from e-cig induces downregulation of Stem-loop binding protein (SLBP) and polyadenylation of canonical histone mRNAs in human bronchial epithelial cells and in mice lungs. Canonical histone mRNAs typically do not end in a poly(A) tail and the acquisition of such a tail via depletion of SLBP has been shown to causes chromosome instability. We show that nicotine-induced SLBP depletion is reversed by an inhibitor of α7-nicotinic acetylcholine receptors (α7-nAChR) or siRNA specific for α7-nAChR, indicating a nAChR-dependent reduction of SLBP by nicotine. Moreover, PI3K/AKT pathway is activated by nicotine exposure and CK2 and probably CDK1, 2 kinases well known for their function for SLBP phosphorylation and degradation, are shown to be involved, α7-nAChR-dependently, in nicotine-induced SLBP depletion. Importantly, nicotine-induced anchorage-independent cell growth is attenuated by inhibition of α7-nAChR and is rescued by overexpression of SLBP. We propose that the SLBP depletion and polyadenylation of canonical histone mRNAs via activation of α7-nAChR and a series of downstream signal transduction pathways are critical for nicotine-induced cell transformation and potential carcinogenesis.

Nicotine Exerts Cytotoxic Effects in a Panel of Healthy Cell Lines and Strong Irritating Potential on Blood Vessels

The use of tobacco products is a major global public health issue, as it is the leading cause of preventable death worldwide. In addition, nicotine (NIC) is a key component of electronic and conventional cigarettes. Although nicotine's addictive potential is well known, its health effects are not entirely understood. Thus, the main objective of the present study was to evaluate its toxicological profile both in vitro, at the level of three healthy cell lines, and in ovo, at the level of the chorioallantoic membrane. Five different concentrations of nicotine were used in keratinocytes, cardiomyocytes, and hepatocytes for the purpose of evaluating cell viability, cell morphology, and its impact on nuclei. Additionally, the hen's egg test on the chorioallantoic membrane (HET-CAM) method was used to assess the biocompatibility and irritant potential of the chorioallantoic membrane. Across all cell lines studied, nicotine was proven to be significantly damaging to cell viability, with the highest concentration tested resulting in less than 2% viable cells. Moreover, the morphology of cells changed dramatically, with alterations in their shape and confluence. Nicotine-induced cell death appears to be apoptotic, based on its impact on the nucleus. In addition, nicotine was also found to have a very strong irritating effect on the chorioallantoic membrane. In conclusion, nicotine has an extremely strong toxicological profile, as demonstrated by the drastic reduction of cell viability and the induction of morphological changes and nuclear alterations associated with cellular apoptosis. Additionally, the HET-CAM method led to the observation of a strong irritating effect associated with nicotine.

Electronic Cigarettes and Their Impact on Allergic Respiratory Diseases: A Work Group Report of the AAAAI Environmental Exposures and Respiratory Health Committee

The explosive rise in popularity of electronic cigarette (e-cig) devices over the past decade has led to controversies over the role of these devices in smoking cessation and harm reduction from combustible cigarette smoking. Increased recognition of potential direct harms of e-cigs, including life-threatening and fatal cases of e-cig and vaping product use-associated lung injury, has emphasized the need to curb use until safety can be established. Of particular concern is the steep rise in e-cig use among teenagers and young adults who have never smoked and among individuals with underlying lung disease, such as asthma. In this report, we describe the different types of e-cig devices available, summarize the available data on the potential health benefits and detriments of e-cig use, and highlight the findings of studies examining e-cigs as smoking cessation tools. Because e-cigs have only gained popularity in the last few years, very few studies have been able to demonstrate an impact of e-cig use on harm reduction related to combustible cigarettes. Moreover, the health effects of e-cigs at a population level must be balanced against the harms of e-cig use, which include nicotine dependence and promoting initiation of cigarette use amongst "never smokers." With respect to smoking cessation, e-cigs appear to serve as switching products that may help individuals reduce or quit cigarette use, but do not address nicotine addiction. Finally, we discuss our recommendations for ways that health care providers can screen and counsel patients on e-cig use. The goal of this report is to provide health care providers with the most recent information on this topic so that they can educate patients on the potential pros and cons of e-cig use.

An update on controversies in e-cigarettes

E-cigarettes are electronic nicotine delivery systems (ENDS) which mimic tobacco smoking without the combustion of tobacco. These devices have been misleadingly marketed as "less harmful" alternatives to conventional smoking tobacco products. The e-liquid in e-cigarettes include nicotine, a humectant and other additives including flavourings, colourants, or adulterants such as bacterial and fungal products. In this review, we discuss the contrasting views of the tobacco lobby and most professional societies. We describe the epidemiology of the use of these devices, with a widespread and significant rise in youth e-cigarette use seen in both the USA and Europe. We also describe what is known about the toxicity and mechanisms of EVALI (e-cigarette or vaping associated lung injury). This characterised by respiratory failure with an intense inflammatory response. The presentations are diverse and clinicians should consider vaping as a possible cause of any unusual respiratory illness in patients who have a history of vaping or other use of e-cigarette-related products. Second hand exposure to e-cigarettes is also harmful through respiration and transdermal absorption. E-cigarettes have a worse acute toxicity than tobacco and their long-term toxicity is unknown, and we advocate for the immediate, most vigorous anti-vaping legislation possible.

COVID's Razor: RAS Imbalance, the Common Denominator Across Disparate, Unexpected Aspects of COVID-19

A modern iteration of Occam's Razor posits that "the simplest explanation is usually correct." Coronavirus Disease 2019 involves widespread organ damage and uneven mortality demographics, deemed unexpected from what was originally thought to be "a straightforward respiratory virus." The simplest explanation is that both the expected and unexpected aspects of COVID-19 share a common mechanism. Silent hypoxia, atypical acute respiratory distress syndrome (ARDS), stroke, olfactory loss, myocarditis, and increased mortality rates in the elderly, in men, in African-Americans, and in patients with obesity, diabetes, and cancer-all bear the fingerprints of the renin-angiotensin system (RAS) imbalance, suggesting that RAS is the common culprit. This article examines what RAS is and how it works, then from that baseline, the article presents the evidence suggesting RAS involvement in the disparate manifestations of COVID-19. Understanding the deeper workings of RAS helps one make sense of severe COVID-19. In addition, recognizing the role of RAS imbalance suggests potential routes to mitigate COVID-19 severity.