Toxicological analysis of aerosols derived from three electronic nicotine delivery systems using normal human bronchial epithelial cells.

Electronic nicotine delivery systems (ENDS) are a rapidly growing global market advertised as a safer alternative to combustible cigarettes. However, comprehensive investigations of END aerosol physicochemical and toxicological properties have not been fully explored across brands to assess relative safety. In this study, we evaluated aerosols collected from three ENDS - Juul Fruit Medley (5% nicotine), Logic Power (2.4% nicotine), and Mistic (1.8% nicotine). ENDS aerosols were generated using standard machine puffing regimen and collected with a novel fluoropolymer condensation trap. Triple quadrupole-inductively coupled plasma-mass determined the presence of heavy metals in collected aerosols. The toxicological effects of ENDS aerosols on normal human bronchial epithelial cells (NHBE) were investigated using cellular viability, reactive oxygen species, oxidative stress assays, along with DNA damage assessments using the CometChip©. Results indicated the total metal concentrations within collected ENDS aerosols were higher for Mistic and Logic compared to Juul. Logic Power aerosols elicited higher reactive oxygen species levels than Mistic and Juul in NHBE after 24-h exposure. Similar dose-dependent reductions of cellular viability and total glutathione were found for each exposure. However, Logic and Juul aerosols caused greater single stranded DNA damage compared to Mistic. Our study indicates that regardless of brand, ENDS aerosols are toxic to upper airway epithelial cells and may pose a potential respiratory hazard to occasional and frequent users.

Vascular and thrombogenic effects of pulmonary exposure to Libby amphibole.

Exposure to Libby amphibole (LA) asbestos is associated with increased incidences of human autoimmune disease and mortality related to cardiovascular diseases. However, the systemic and vascular impacts are less well examined because of the dominance of pulmonary disease. It was postulated that regardless of the type of exposure scenario, LA exposure might produce systemic and vascular inflammogenic and thrombotic alterations in healthy and cardiovascular compromised rat models. Samples from three independent studies were examined. In the first study, male Wistar Kyoto (WKY), spontaneously hypertensive (SH), and SH heart failure (SHHF) rats were intratracheally instilled once with 0 (vehicle), 0.25, or 1 mg/rat of LA. In the second study, F344 rats were instilled with vehicle or LA at 0.5, 1.5, or 5 mg/rat. In the third study, F344 rats were instilled with the same mass concentrations of LA delivered by biweekly multiple instillations over 3 mo to simulate an episodic subchronic exposure. Complete blood count, platelet aggregation, serum cytokines, and biomarkers of systemic and aortic effects were examined. LA reduced adenosine diphosphate (ADP)-induced platelet aggregation and decreased circulating platelets in WKY (1 mg/rat) and F344 (5 mg/rat) at the 3-mo time point but did not do so in SH or SHHF rats. A decline in circulating lymphocytes with age appeared to be exacerbated by LA exposure in F344 rats but the differences were not significant. Aorta mRNA expression for biomarkers of oxidative stress (HO-1, LOX-1), inflammation (MIP-2), and thrombosis (tPA, PAI-1, vWf) were increased at baseline in SH and SHHF relative to WKY. LA exposure upregulated several of these biomarkers and also those involved in aortic contractility of WKY rats at 3 mo, suggesting thrombogenic, vasocontractile, and oxidative stress-mediated impairments. The aorta changes in F344 rats were less remarkable than changes noted in WKY following LA exposure. In conclusion, exposure to LA decreased circulating platelets and platelet coagulability while increasing the expression of oxidative stress, thrombosis, and vasoconstriction biomarkers in the aorta of healthy rats. These changes were similar to those noted at baseline in SH and SHHF rats, suggesting that LA-induced pulmonary injury might increase the risk of developing cardiovascular disease in healthy individuals.

Long-term response of rats to single intratracheal exposure of Libby amphibole or amosite.

In former mine workers and residents of Libby, Montana, exposure to amphibole-contaminated vermiculite has been associated with increased incidences of asbestosis and mesothelioma. In this study, long-term effects of Libby amphibole (LA) exposure were investigated relative to the well-characterized amosite asbestos in a rat model. Rat-respirable fractions of LA and amosite (aerodynamic diameter≤2.5 µm) were prepared by water elutriation. Male F344 rats were exposed to a single dose of either saline, amosite (0.65 mg/rat), or LA (0.65 or 6.5 mg/rat) by intratracheal (IT) instillation. One year after exposure, asbestos-exposed rats displayed chronic pulmonary inflammation and fibrosis. Two years postexposure, lung inflammation and fibrosis progressed in a time- and dose-dependent manner in LA-exposed rats, although the severity of inflammation and fibrosis was smaller in magnitude than in animals exposed to amosite. In contrast, gene expression of the fibrosis markers Col 1A2 and Col 3A1 was significantly greater in LA-exposed compared to amosite-exposed rats. There was no apparent evidence of preneoplastic changes in any of the asbestos-exposed groups. However, all asbestos-exposed rats demonstrated a significant increase in the expression of epidermal growth factor receptor (EGFR) 2 yr after instillation. In addition, only LA-exposed rats showed significant elevation in mesothelin (Msln) and Wilms' tumor gene (WT1) expression, suggesting possible induction of tumor pathways. These results demonstrate that a single IT exposure to LA is sufficient to induce significant fibrogenic, but not carcinogenic, effects up to 2 yr after exposure that differ both in quality and magnitude from those elicited by amosite administration at the same mass dose in F344 rats. Data showed that LA was on a mass basis less potent than amosite.

Transcriptional activation of inflammasome components by Libby amphibole and the role of iron.

The induction of the NALP3 inflammasome complex is shown to be necessary for the development of fibrosis after asbestos exposure. Libby amphibole (LA) induces lung inflammation and fibrosis, while complexation of iron (Fe) on fibers inhibits inflammation. In this study we examined the ability of LA to induce the inflammasome cascade and the role of Fe in modulating inflammasome activity. Spontaneously hypertensive rats were exposed intratracheally to either saline (300 µl), deferoxamine (Def) (1 mg), FeCl(3) (21 µg), LA (0.5 mg), Fe-loaded LA (Fe + LA), or LA + Def. Activities of oxidative stress-sensitive enzymes, expression of inflammasome-specific genes, and cytokine proteins in bronchoalveolar lavage fluid were analyzed. Lung enzymes at 4 h and 24 h post-exposure were unchanged. LA increased lung expression of genes including interleukin-1ß (IL-1ß), cathepsin-B, ASC, NALP3, interleukin (IL)-6 and NFκB. LA+Fe significantly reduced IL-1ß and NFκB with a trend of reduction in ASC, NALP3, cathepsin-B and IL-6 expression. Def treatment did not reverse the inhibitory effect of Fe on IL-1ß and ASC but reversed IL-6 expression. CCL-7, CCL-12, CXCL-3 and COX-2 were induced by LA while LA+Fe tended to reduce these responses. Phosphorylation of ERK but not MEK was increased at 4 h after LA but not LA+Fe exposure. In conclusion, components of the NALP3 inflammasome are transcriptionally activated acutely during LA-induced inflammation. The key inflammatory regulators IL-1ß and NFκB were inhibited in the presence of surface-complexed Fe possibly through decreased ERK signaling upstream of the NALP3 inflammasome. The inflammasome activation by LA may contribute to fibrosis, and Fe may reduce this response and alter compensatory mechanisms in individuals exposed to LA.

Long-term results of intraoperative balloon dilatation.

A review was conducted of 61 patients who underwent intraoperative balloon dilatation over the past five years. Of the 62 dilatations in this patient group, 80% were performed in conjunction with a reconstructive procedure, and 20% were performed as a primary procedure. Dilatations were performed with the linear extrusion balloon catheter. A 94% rate of followup was achieved, with a mean followup of 16.3 months (range 1-60 months). Life table analysis reveals a 95% initial success rate decreasing to an 81% patency rate by the end of the fifth year for iliac dilatations, a 97% initial and 58% five-year patency rate for superficial femoral dilatations, and an 86% initial and 37% five-year patency rate for popliteal dilatations. 21.3% of the patients died during the followup period. No deaths occurred as a result of intraoperative angioplasty. One arterial rupture occurred, requiring a bypass graft at the same surgery. We conclude that intraoperative balloon dilatation in an adjunctive setting may offer clinical benefits to vascular patients while requiring little additional operative time.

Use of a computer to group actinomycetes for studies on the ecology of soil microorganisms.

A computer program has been prepared for grouping soil actinomycetes into cluster groups based on the presence or absence of aerial mycelium, the color of soluble pigment, and the shade of color of surface and reverse mycelium. The program automatically condenses cultures with wide ranges of characteristics into a limited number of groups and provides a permanent record so that comparisons can be made among experiments performed over a span of time. The program permits the grouping of large numbers of cultures with minimal laboratory effort and has proven useful in defining some of the ecological factors that lead to changed actinomycete populations in soils.