E-cigarettes induce toxicity comparable to tobacco cigarettes in airway epithelium from patients with COPD.

BACKGROUND: The health effects of e-cigarettes in patients with pre-existing lung disease are unknown. The aim of this study was to investigate whether aerosols from a fourth-generation e-cigarette produces similar in-vitro cytotoxic, DNA damage and inflammatory effects on bronchial epithelial cells (BECs) from patients with COPD, as cigarette smoke. METHODS: BECs from patients with COPD who underwent surgery for lung cancer and comparator (immortalised 16HBE) cells were grown at air liquid interface (ALI). BECs were exposed to aerosols from a JUUL® e-cigarette (Virginia Tobacco and Menthol pods at 5% nicotine strength) or reference 3R4F cigarette for 30 min at ALI. Cell cytotoxicity, DNA damage and inflammation were measured. RESULTS: In response to the Virginia Tobacco and Menthol flavoured e-cigarette aerosols, COPD BECs showed comparable LDH release (cell cytotoxicity, p = 0.59, p = 0.67 respectively), DNA damage (p = 0.41, p = 0.51) and inflammation (IL-8, p = 0.20, p = 0.89 and IL-6, p = 0.24, p = 0.93), to cigarette smoke. 16HBE cells also showed comparable cellular responses to cigarette smoke. CONCLUSION: In airway cells from patients with COPD, aerosols from a fourth-generation e-cigarette were associated with similar toxicity to cigarette smoke. These results have potential implications for the safety of e-cigarette use in patients with lung disease.

Role of semi-volatile particulate matter in gas-particle partitioning leading to change in oxidative potential.

Atmospheric semi-volatile organic compounds (SVOCs) are complex in their chemical and toxicological characteristics with sources from both primary combustion emissions and secondary oxygenated aerosol formation processes. In this study, thermal desorption of PM2.5 in association with online measurement of reactive oxygen species (ROS) was carried out to study the role of SVOCs in its gas-particle partitioning. The mass concentrations of PM2.5, black carbon (BC) and p-PAHs downstream of a thermodenuder were measured online at different temperature settings (25, 50, 100, and 200 °C) to characterize PM physico-chemical properties. While the mass concentrations of PM2.5 and p-PAHs reduced to ∼34% at 200 °C compared to that in ambient temperature, BC mass concentration has decreased by 30% at the highest temperature. Furthermore, the submicron particle size distribution showed reduced particle number concentration in Aitken mode at 200 °C heating. The ROS, measured by Particle-into-Nitroxide-Quencher, also showed reduction and followed a similar trend with PM measurements, where the total ROS decreased by 12%, 31%, and 53% at 50 °C, 100 °C, and 200 °C, respectively, compared to the ambient sample. When a HEPA filter was included in the upstream of samples, 39% of gas phase ROS reduction was observed at 200 °C. This provided a good estimate of the contribution of SVOCs in ROS production in PM2.5, where decreased SVOCs concentration at 200 °C increased the percentage of particle surface area. This concludes that the surface chemistry of these organic coatings on the particles is important for assessing the health impacts of PM.

Relationship between Atmospheric PM-Bound Reactive Oxygen Species, Their Half-Lives, and Regulated Pollutants: Investigation and Preliminary Model.

The concentration, nature, and persistence of particulate matter (PM)-bound reactive oxygen species (ROS) are of significant interest in understanding how atmospheric pollution affects health. However, the inherent difficulties in their measurement, particularly regarding the so-called "short-lived" ROS, have limited our understanding of their persistence and concentrations in the atmosphere. This paper aims to address this limitation through the analysis of PM-bound ROS measurements from the Particle Into Nitroxide Quencher (PINQ) system at an atmospheric monitoring site in the city of Heshan, Guangdong Province, China. The measured daily average and standard deviation for the measurement period was 0.050 ± 0.017 nmol·m-3. The averaged measured concentration of ROS per mass of PM and standard deviation was 0.0012 ± nmol·mg. The dataset was also correlated with standard pollutants, and a simplified model was constructed to separate the contributions of short-lived (t1/2 = 5 min) and long-lived (t1/2 ∼ infinity) ROS to total concentration using ozone, carbon monoxide, and PM mass. This showed that the short-lived ROS contribute an average of 33% of the daily PM-bound ROS burden over the measurement period, up to 52% of daily average on elevated days, and up to 71% for hourly averages. These results highlight the need for accurate measurements of short-lived ROS and provide the starting point for a general model to predict PM-bound ROS concentrations using widely available standard pollutants for future epidemiological research.

Measurements of Oxidative Potential of Particulate Matter at Belgrade Tunnel; Comparison of BPEAnit, DTT and DCFH Assays.

To estimate the oxidative potential (OP) of particulate matter (PM), two commonly used cell-free, molecular probes were applied: dithiothreitol (DTT) and dichloro-dihydro-fluorescein diacetate (DCFH-DA), and their performance was compared with 9,10-bis (phenylethynyl) anthracene-nitroxide (BPEAnit). To the best of our knowledge, this is the first study in which the performance of the DTT and DCFH has been compared with the BPEAnit probe. The average concentrations of PM, organic carbon (OC) and elemental carbon (EC) for fine (PM2.5) and coarse (PM10) particles were determined. The results were 44.8 ± 13.7, 9.8 ± 5.1 and 9.3 ± 4.8 µg·m-3 for PM2.5 and 75.5 ± 25.1, 16.3 ± 8.7 and 11.8 ± 5.3 µg·m-3 for PM10, respectively, for PM, OC and EC. The water-soluble organic carbon (WSOC) fraction accounted for 42 ± 14% and 28 ± 9% of organic carbon in PM2.5 and PM10, respectively. The average volume normalized OP values for the three assays depended on both the sampling periods and the PM fractions. The OPBPEAnit had its peak at 2 p.m.; in the afternoon, it was three times higher compared to the morning and late afternoon values. The DCFH and BPEAnit results were correlated (r = 0.64), while there was no good agreement between the BPEAnit and the DTT (r = 0.14). The total organic content of PM does not necessarily represent oxidative capacity and it shows varying correlation with the OP. With respect to the two PM fractions studied, the OP was mostly associated with smaller particles.

Application of a Fluorescent Probe for the Online Measurement of PM-Bound Reactive Oxygen Species in Chamber and Ambient Studies.

This manuscript details the application of a profluorescent nitroxide (PFN) for the online quantification of radical concentrations on particulate matter (PM) using an improved Particle Into Nitroxide Quencher (PINQ). A miniature flow-through fluorimeter developed specifically for use with the 9,10-bis(phenylethynyl)anthracene-nitroxide (BPEAnit) probe was integrated into the PINQ, along with automated gas phase corrections through periodic high efficiency particle arrestor (HEPA) filtering. The resulting instrument is capable of unattended sampling and was operated with a minimum time resolution of 2.5 min. Details of the fluorimeter design and examples of data processing are provided, and results from a chamber study of side-stream cigarette smoke and ambient monitoring campaign in Guangzhou, China are presented. Primary cigarette smoke was shown to have both short-lived (t1/2 = 27 min) and long-lived (t1/2 = indefinite) PM-bound reactive oxygen species (ROS) components which had previously only been observed in secondary organic aerosol (SOA).