Inflammatory biomarkers and growth factors in saliva and gingival crevicular fluid of e-cigarette users, cigarette smokers, and dual smokers: A pilot study.

BACKGROUND: Cigarette smoking remains one of the leading public health threats worldwide. Electronic cigarettes (e-cigs) provide an alternative to conventional cigarette smoking; however, the evidence base of risks and benefits of e-cig use is new and growing. In this cross-sectional pilot study, the effect of e-cig use on biological profiles in saliva and gingival crevicular fluid (GCF) was assessed and compared with the profiles of cigarette smokers (CS), dual users, and non-users. The systemic inflammatory mediators between e-cig users (EC) and these other groups were also assessed. METHODS: This pilot cross-sectional study recruited volunteer participants consisting of four groups, non-smokers (NS), CS, EC, and dual EC and cigarette smokers (DS). Saliva and GCF samples were collected and analyzed for biomarkers of inflammation, oxidative stress, anti-inflammatory lipid mediators, tissue injury and repair, and growth factors with immunoassay (enzyme-linked immunosorbent assay and Luminex). RESULTS: Smoking status was confirmed via salivary cotinine. Prostaglandin E2 level was significantly increased in CS compared with EC and DS, but not significantly different in EC and DS groups compared with non-smokers (NS). Statistically significant differences were observed between groups of EC and NS (myeloperoxidase [MPO], matrix metalloproteinase-9) as well as between DS and EC for biomarkers of inflammatory mediators (receptor for advanced glycation end products [RAGE], MPO, uteroglobin/CC-10); between groups of DS and NS for extracellular newly identified RAGE binding protein and between CS and NS for MPO. No statistically significant differences in biomarkers of immunity (S100A8, S100A9, galectin-3), tissue injury and repair (Serpine1/PAI-1) and growth factors (brain-derived neurotrophic factor, fibroblast growth factors, platelet-derived growth factor-AA, vascular endothelial growth factor, and others) were found between any of groups. CONCLUSION: Statistically significant differences in measurable health outcomes were found between different smoking status groups, suggesting that smoking/vaping produces differential effects on oral health.

Systemic biomarkers of inflammation, oxidative stress and tissue injury and repair among waterpipe, cigarette and dual tobacco smokers.

BACKGROUND: Waterpipe tobacco (WPT) smoking is associated with deleterious effects on cardio-pulmonary systems which may have adverse repercussions in pathophysiology and progression of chronic lung and cardiovascular diseases. We compared the biomarkers of systemic inflammation, lipid mediators, injury/repair and oxidative stress between groups of non-smokers (NS), exclusive WPT smokers (WPS), exclusive cigarette smokers (CS) and dual WPS and CS (DS). METHODS: Two cohorts were recruited. Cohort I consisted of WPS (n=12), CS (n=26), DS (n=10) and NS (n=25). Cohort II consisted of WPS (n=33) and NS (n=24). Plasma and urine samples were collected and analysed for various systemic biomarkers. RESULTS: Compared with NS, plasma levels of inflammatory mediators (interleukin (IL)-6, IL-8, IL1ß and tumor necrosis factor-α) were significantly higher in WPS and CS, and were further augmented in DS. Endothelial biomarkers (intracellular adhesion molecule-1, prostaglandin E-2 and metalloproteinase-9) were significantly higher in CS. Most notably, pro-resolving lipid mediator (resolvin E1) and biomarkers of immunity, tissue injury, and repair were significantly lower in WPS and CS. Urinary levels of 8-isoprostane were significantly higher in all smoking groups in cohort I, while 8-isoprostane, myeloperoxidase, receptor for advanced glycation end products (RAGE), En-RAGE and matrix metalloproteinase-9 were significantly higher in all smoking groups in cohort II. CONCLUSIONS: Biomarkers of inflammation, oxidative stress, immunity, tissue injury and repair were elevated in WPS and CS groups. Furthermore, concurrent use of WPT and cigarettes is more harmful than cigarette or WPT smoking alone. These data may help inform the public and policy-makers about the dangers of WPT smoking and dual use of tobacco products.

Systemic biomarkers in electronic cigarette users: implications for noninvasive assessment of vaping-associated pulmonary injuries.

BACKGROUND: Electronic cigarettes (e-cigs) were introduced as electronic nicotine delivery systems, and have become very popular in the USA and globally. There is a paucity of data on systemic injury biomarkers of vaping in e-cig users that can be used as a noninvasive assessment of vaping-associated lung injuries. We hypothesised that characterisation of systemic biomarkers of inflammation, anti-inflammatory, oxidative stress, vascular and lipid mediators, growth factors, and extracellular matrix breakdown may provide information regarding the toxicity of vaping in e-cig users. METHODS: We collected various biological fluids, i.e. plasma, urine, saliva and exhaled breath condensate (EBC), measured pulmonary function and vaping characteristics, and assessed various biomarkers in e-cig users and nonusers. RESULTS: The plasma samples of e-cig users showed a significant increase in biomarkers of inflammation (interleukin (IL)-1ß, IL-6, IL-8, IL-13, interferon (IFN)-γ, matrix metalloproteinase-9, intercellular cell adhesion molecule-1) and extracellular matrix breakdown (desmosine), and decreased pro-resolving lipid mediators (resolvin D1 and resolvin D2). There was a significant increase in growth factor (endothelial growth factor, vascular endothelial growth factor, ß-nerve growth factor, platelet-derived growth factor-AA, stem cell factor, hepatocyte growth factor and placental growth factor) levels in plasma of e-cig users versus nonusers. E-cig users showed a significant increase in levels of inflammatory biomarker IFN-γ, oxidative stress biomarker 8-isoprostane and oxidative DNA damage biomarker 8-oxo-dG in urine samples, and of inflammatory biomarker IL-1ß in saliva samples. EBC showed a slight increase in levels of triglycerides and 8-isoprostane in e-cig users compared with normal nonusers. CONCLUSION: E-cig users have increased levels of biomarkers of inflammation and oxidative stress, reduced pro-resolving anti-inflammatory mediators, and endothelial dysfunction, which may act as risk factors for increasing susceptibility to systemic diseases. The identified noninvasive biomarkers can be used for determining e-cig vaping-associated lung injuries, and for regulatory and diagnostic aspects of vaping in humans.

Classification of flavors in cigarillos and little cigars and their variable cellular and acellular oxidative and cytotoxic responses.

Flavored tobacco products are increasing in popularity but remain unregulated, with the exception of the ban on flavored conventional cigarettes. Lack of regulation of cigarillos and little cigars allows vendors to have their own version of popular flavors, each with different chemical components. A new classification system was created for flavored cigars in order to easily communicate our results with the scientific community. To understand the physicochemical characteristics of flavored little cigars and cigarillo smoke, size distribution and concentration of particulate matter in smoke were determined. Acellular reactive oxygen species generation was measured as an indirect measurement of the potential to cause oxidative stress in cells. In addition, cigarillo smoke extract treatment on bronchial epithelial (Beas-2b) cells were assessed to determine the flavor-induced cellular toxicity. Flavored cigars/cigarillos showed significant variability in the tested parameters between flavors as well as brands of the same flavor, but most of the cigars showed higher potential of generating oxidative stress, than research grade cigarettes. Flavored cigars produced maximum particle concentrations at 1.0µm and 4.0 µm compared with 3R4F reference research cigarettes. A differential cytotoxic response was observed with cigarillo smoke extract treatments, with "fruits/candy" and "drinks" being the most toxic, but were not more cytotoxic than smoke from cigarettes. These cigarillos with flavors must be well characterized for toxicity in order to prevent adverse effects caused by exposure to flavor chemicals. Our study provides insight into understanding the potential health effects of flavor-infused cigars/cigarillos and the need for the regulation of those flavoring chemicals in these products. Future research is directed to determine the flavoring toxicity of little cigars and cigarillos in vivo studies.

Dysregulated repair and inflammatory responses by e-cigarette-derived inhaled nicotine and humectant propylene glycol in a sex-dependent manner in mouse lung.

Nicotine inhalation via electronic cigarettes (e-cigs) is an emerging concern. However, little is known about the acute toxicity in the lungs following inhalation of nicotine-containing e-cig aerosols. We hypothesized that acute exposure to aerosolized nicotine causes lung toxicity by eliciting inflammatory and dysregulated repair responses. Adult C57BL/6J mice were exposed 2 h daily for 3 days to e-cig aerosols containing propylene glycol (PG) with or without nicotine. Acute exposure to nicotine-containing e-cig aerosols induced inflammatory cell influx (neutrophils and CD8a+ T-lymphocytes), and release of pro-inflammatory cytokines in bronchoalveolar lavage fluid in a sex-dependent manner. Inhalation of e-cig aerosol containing PG alone significantly augmented the lung levels of various homeostasis/repair mediators (PPARγ, ADRP, ACTA2, CTNNB1, LEF1, ß-catenin, E-cadherin, and MMP2) in a sex-dependent manner when compared to air controls. These findings were accompanied by an increase in protein abundance and altered gene expression of lipogenic markers (PPARγ, ADRP) and myogenic markers (fibronectin, α-smooth muscle actin and ß-catenin), suggesting a dysregulated repair response in mouse lungs. Furthermore, exposure to nicotine containing e-cig aerosols or PG alone differentially affected the release of pro-inflammatory cytokines in healthy and COPD human 3D EpiAirway tissues. Overall, acute exposure to nicotine containing e-cig aerosols was sufficient to elicit a pro-inflammatory response and altered mRNA and protein levels of myogenic, lipogenic, and extracellular matrix markers in mouse lung in a sex-dependent manner. Thus, acute exposure to inhaled nicotine via e-cig leads to dysregulated repair and inflammatory responses, which may lead to airway remodeling in the lungs.