ABSTRACT
Electronic cigarette (e-cig) vaping is increasing rapidly in the United States, as e-cigs are considered less harmful than combustible cigarettes. However, limited research has been conducted to understand the possible mechanism that mediate, toxicity and pulmonary health effects of e-cigs. We hypothesized that sub-chronic e-cig exposure induces inflammatory response and dysregulated repair/extracellular matrix (ECM) remodeling, which occur through the α7 nicotinic acetylcholine receptor (nAChR α7). Adult wild-type (WT), nAChRα7 knockout (KO), and lung epithelial cell-specific KO (nAChRα7 CreCC10) mice were exposed to e-cig aerosol containing propylene glycol (PG) with or without nicotine. Bronchoalveolar lavage fluids (BALF) and lungs tissues were collected to determine e-cig induced inflammatory response and ECM remodeling, respectively. Sub-chronic e-cig exposure with nicotine increased the inflammatory cellular influx of macrophages and T-lymphocytes including increased pro-inflammatory cytokines in BALF and increased ACE2 Covid-19 receptor, whereas nAChR α7 KO mice show reduced inflammatory responses associated with decreased ACE2 receptor. Interestingly, matrix metalloproteinases (MMPs), such as MMP2, MMP8, and MMP9 were altered both at the protein and mRNA transcript levels in female and male, but WT mice exposed to PG alone showed a sex-dependent phenotype. Moreover, MMP12 was increased significantly in male mice exposed to PG with or without nicotine in a nAChR α7-dependent manner. Additionally, sub-chronic e-cig exposure with or without nicotine altered the abundance of ECM proteins, such as collagen and fibronectin significantly in a sex-dependent manner, but without the direct role of nAChR α7 gene. Overall, sub-chronic e-cig exposure with or without nicotine affected lung inflammation and repair responses/ECM remodeling, which were mediated by nAChR α7 in a sex-dependent manner.
ABSTRACT
Electronic cigarette (e-cig) vaping is increasing rapidly in the United States, as e-cigs are considered less harmful than combustible cigarettes. However, limited research has been conducted to understand the possible mechanisms that mediate toxicity and pulmonary health effects of e-cigs. We hypothesized that sub-chronic e-cig exposure induces inflammatory response and dysregulated repair/extracellular matrix (ECM) remodeling, which occur through the α7 nicotinic acetylcholine receptor (nAChRα7). Adult wild-type (WT), nAChRα7 knockout (KO), and lung epithelial cell-specific KO (nAChRα7 CreCC10) mice were exposed to e-cig aerosol containing propylene glycol (PG) with or without nicotine. Bronchoalveolar lavage fluids (BALF) and lung tissues were collected to determine e-cig induced inflammatory response and ECM remodeling, respectively. Sub-chronic e-cig exposure with nicotine increased inflammatory cellular influx of macrophages and T-lymphocytes including increased pro-inflammatory cytokines in BALF and increased SARS-Cov-2 Covid-19 ACE2 receptor, whereas nAChRα7 KO mice show reduced inflammatory responses associated with decreased ACE2 receptor. Interestingly, matrix metalloproteinases (MMPs), such as MMP2, MMP8 and MMP9, were altered both at the protein and mRNA transcript levels in female and male KO mice, but WT mice exposed to PG alone showed a sex-dependent phenotype. Moreover, MMP12 was increased significantly in male mice exposed to PG with or without nicotine in a nAChRα7-dependent manner. Additionally, sub-chronic e-cig exposure with or without nicotine altered the abundance of ECM proteins, such as collagen and fibronectin, significantly in a sex-dependent manner, but without the direct role of nAChRα7 gene. Overall, sub-chronic e-cig exposure with or without nicotine affected lung inflammation and repair responses/ECM remodeling, which were mediated by nAChRα7 in a sex-dependent manner.
Subject(s)
Coronavirus Infections/epidemiology , Electronic Nicotine Delivery Systems , Peptidyl-Dipeptidase A/metabolism , Pneumonia, Viral/epidemiology , Pneumonia/metabolism , Vaping/adverse effects , alpha7 Nicotinic Acetylcholine Receptor/genetics , Angiotensin-Converting Enzyme 2 , Animals , Blood Gas Analysis , Blotting, Western , Bronchoalveolar Lavage Fluid , COVID-19 , Cytokines/analysis , Disease Models, Animal , Female , Humans , Male , Mice , Mice, Inbred C57BL , Mice, Knockout , Pandemics , Pneumonia/physiopathology , Random Allocation , Reference Values , Role , Severe Acute Respiratory Syndrome/epidemiology , Signal Transduction/geneticsABSTRACT
Background: Tobacco smoking is known to be involved in the pathogenesis of several cardiopulmonary diseases. Additionally, smokers are highly susceptible to infectious agents due to weakened immunity. However, the progression of lung injury based on SARS-CoV-2-mediated COVID-19 pathogenesis amongst smokers and those with pre-existing pulmonary diseases is not known. We determined the systemic levels and activity of COVID-19 associated proteins, cytokine/chemokines, and lipid mediators (lipidomics) amongst COVID-19 patients with and without a history of smoking to understand the underlying susceptible factor in the pathogenesis of COVID-19. Methods: We obtained serum from healthy (CoV-), COVID-19 positive (CoV+), and COVID-19 recovered (CoV Rec) subjects with and without a history of smoking. We conducted a Luminex multiplex assay (cytokine levels), LC/MS (eicosanoids or oxylipin panel), and ACE2 enzymatic activity assays on the serum samples to determine the systemic changes in COVID-19 patients. Results: On comparing the levels of serum ACE2 amongst COVID-19 (positive and recovered) patients and healthy controls, we found a pronounced increase in serum ACE2 levels in patients with COVID-19 infection. Furthermore, ACE2 enzyme activity was significantly increased amongst COVID-19 patients with a smoking history. Also, we analyzed the levels of Angiotensin 1-7 (Ang1-7) peptide, the product of enzymatic action of ACE2, in the serum samples. We found significantly high levels of Ang1-7 in the serum of both CoV+ and CoV Rec patients. Our data further demonstrated a smoking-induced increase in serum furin and inflammatory cytokine [IFNγ(p = 0.0836), Eotaxin (p < 0.05), MCP-1 (p < 0.05), and IL-9 (p = 0.0991)] levels in COVID-19 patients as compared to non-smoking controls. Overall, our results show that smoking adversely affects the levels of systemic inflammatory markers and COVID-19 associated proteins, thus suggesting that COVID-19 infection may have severe outcomes amongst smokers.
ABSTRACT
Rationale Definitive causative agents of the outbreak associated with the use of e-cigarette, or vaping product use associated lung injury (EVALI) are unknown. Patients diagnosed with EVALI have used vape products containing tetrahydrocannabinol (THC) and vitamin E acetate (VEA). Hypothesis We hypothesized that inhalation of these EVALI vape cartridges and their constituents induce pulmonary toxicity, mediated by oxidative damage and inflammatory responses, leading to acute lung injury, and alters SARS-CoV-2 related proteins. Methods Vaping products were recovered from hospitalized patients at the University of Rochester Medical Center. Cartridge constituents were characterized by gas chromatography and mass spectrometry. Comparative toxicity of exposure to common vape cartridge components such as medium-chain triglyceride (MCT) oil, VEA, and patient-derived cartridge aerosols was assessed by in vitro and in vivo models. Lung epithelial cells (BEAS-2B) and monocytes (Mono-Mac-6). Cells were exposed to MCT, VEA, and cartridge aerosols and the elicited inflammatory response, barrier function, and lipid-laden index were determined. C57BL/6 mice were exposed to MCT, VEA, and vape cartridge aerosols for three days (1 hr/day). The immune response was determined by differential cell counts, cytokine milieu, and lipidomics analysis in bronchoalveolar lavage fluid (BALF). Lung surfactant protein (SP-A), SARS-CoV-2 proteins (ACE2 and TMPRSS2) were quantified in the lung homogenates. Results Constituents identified patient-derived vaping products included reactive hydrocarbons and various forms of cannabinoids. VEA and cartridge aerosols induced significantly increased IL-6 and IL-8 responses in lung epithelial cells and monocytes. MCT, VEA, and cartridge aerosols induced barrier dysfunction. Increased lipid-laden indices were observed in MM6 cells. In mice, acute exposure to cartridge aerosols caused a significant infiltration of leukocytes in BALF and increased IL-6, eotaxin, and G-CSF in the BALF. Lipidomics analysis showed significantly increased eicosanoid inflammatory mediators and leukotrienes. Reduced levels of SP-A levels were seen in lung homogenates. Exposure to cartridge aerosols showed the most significant effects and toxicity compared to MCT and VEA. SARS-CoV-2 related proteins were not affected. Conclusion Acute exposure to vape cartridges induces cytotoxicity, barrier dysfunction, and elicit an inflammatory response in lung cells and mice, which are potential predictive toxicological markers of EVALI. Toxicity of vape cartridges was independent of SARS-CoV-2 proteins. This study provides important identification of potential chemical constituents, toxicological responses, and potential biomarkers of EVALI.
ABSTRACT
Recently, there has been an outbreak associated with the use of e-cigarette or vaping products, associated lung injury (EVALI). The primary components of vaping products, vitamin E acetate (VEA) and medium-chain triglycerides (MCT), may be responsible for acute lung toxicity. Currently, little information is available on the physiological and biological effects of exposure to these products. We hypothesized that these e-cig vape cartridges and their constituents (VEA and MCT) induce pulmonary toxicity, mediated by oxidative damage and inflammatory responses, leading to acute lung injury. We studied the potential mechanisms of e-cig vape cartridge aerosol induced inflammatory response by evaluating the generation of reactive oxygen species by MCT, VEA, and cartridges and their effects on the inflammatory state of pulmonary epithelium and immune cells both in vitro and in vivo. Cells exposed to these aerosols generated reactive oxygen species, caused cytotoxicity, induced epithelial barrier dysfunction, and elicited an inflammatory response. Using a murine model, the parameters of acute toxicity to aerosol inhalation were assessed. Infiltration of neutrophils and lymphocytes was accompanied by significant increases in IL-6, eotaxin, and G-CSF in the bronchoalveolar lavage fluid (BALF). In mouse plasma, eicosanoid inflammatory mediators, leukotrienes, were significantly increased. Plasma from e-cig users also showed increased levels of hydroxyeicosatetraenoic acid (HETEs) and various eicosanoids. Exposure to e-cig vape cartridge aerosols showed the most significant effects and toxicity compared to MCT and VEA. In addition, we determined SARS-CoV-2 related proteins and found no impact associated with aerosol exposures from these tested cartridges. Overall, this study demonstrates acute exposure to specific e-cig vape cartridges induces in vitro cytotoxicity, barrier dysfunction, and inflammation and in vivo mouse exposure induces acute inflammation with elevated proinflammatory markers in the pathogenesis of EVALI.