The EMPOWER program: a history and guide for increasing diversity using integrated research and education.

The prevalence and pervasive nature of emerging chemicals of concern have created widespread environmental injustice apprehensions in vulnerable communities. To alleviate and address these concerns, identifying, engaging, and training a diverse environmental health research workforce will be critical and necessary steps to combat and prevent the consequences of environmental injustice. While there is an obvious need to enhance diversity in environmental health research, this process is hampered by facets of systemic racism that reduce access to educational resources needed to build interest and knowledge in students and teachers. We present here a historical perspective to offer a guide for building programs and relationships with underserved schools to help overcome limiting factors that have plagued certain public school systems. With the proper training and mentorship, the untapped workforce present within these schools will be empowered to understand and address current and emerging environmental health and safety threats. Through this transformative 8-week high school research program, we will develop well-prepared, ethical researchers committed to scientific inquiry, intensive fieldwork, and collaborative problem solving to address environmental health challenges. Following the four-step risk assessment process, students, teachers, and faculty mentors will work collaboratively to identify toxicants, potential hazards and risks, and environmental disparities in urban neighborhoods, which provides the necessary training to formulate critical thinking skills for use in academic or nonacademic careers.NEW & NOTEWORTHY The Engaging Multidisciplinary Professional Opportunities for Women in Environmental Research (EMPOWER) program is a one-of-a-kind research summer experience for minority female high school students in the state of Georgia. In addition, this program provides high school teachers with hands-on experiences that can be adapted to use in the classrooms. This combination of lab and field research immerses participants in understanding urban environmental exposures and their health effects. The EMPOWER program was established to meet the critical need for increasing diversity in science, technology, engineering, and mathematics.

Real-Time Exposure to 3D-Printing Emissions Elicits Metabolic and Pro-Inflammatory Responses in Human Airway Epithelial Cells.

Three-dimensional (3D) printer usage in household and school settings has raised health concerns regarding chemical and particle emission exposures during operation. Although the composition of 3D printer emissions varies depending on printer settings and materials, little is known about the impact that emissions from different filament types may have on respiratory health and underlying cellular mechanisms. In this study, we used an in vitro exposure chamber system to deliver emissions from two popular 3D-printing filament types, acrylonitrile butadiene styrene (ABS) and polylactic acid (PLA), directly to human small airway epithelial cells (SAEC) cultured in an air-liquid interface during 3D printer operation. Using a scanning mobility particle sizer (SMPS) and an optical particle sizer (OPS), we monitored 3D printer particulate matter (PM) emissions in terms of their particle size distribution, concentrations, and calculated deposited doses. Elemental composition of ABS and PLA emissions was assessed using scanning electron microscopy coupled with energy dispersive X-ray spectroscopy (SEM-EDX). Finally, we compared the effects of emission exposure on cell viability, inflammation, and metabolism in SAEC. Our results reveal that, although ABS filaments emitted a higher total concentration of particles and PLA filaments emitted a higher concentration of smaller particles, SAEC were exposed to similar deposited doses of particles for each filament type. Conversely, ABS and PLA emissions had distinct elemental compositions, which were likely responsible for differential effects on SAEC viability, oxidative stress, release of inflammatory mediators, and changes in cellular metabolism. Specifically, while ABS- and PLA-emitted particles both reduced cellular viability and total glutathione levels in SAEC, ABS emissions had a significantly greater effect on glutathione relative to PLA emissions. Additionally, pro-inflammatory cytokines including IL-1ß, MMP-9, and RANTES were significantly increased due to ABS emissions exposure. While IL-6 and IL-8 were stimulated in both exposure scenarios, VEGF was exclusively increased due to PLA emissions exposures. Notably, ABS emissions induced metabolic perturbation on amino acids and energy metabolism, as well as redox-regulated pathways including arginine, methionine, cysteine, and vitamin B3 metabolism, whereas PLA emissions exposures caused fatty acid and carnitine dysregulation. Taken together, these results advance our mechanistic understanding of 3D-printer-emissions-induced respiratory toxicity and highlight the role that filament emission properties may play in mediating different respiratory outcomes.

Characterization of an Electronic Nicotine Delivery System (ENDS) Aerosol Generation Platform to Determine Exposure Risks.

Evaluating vaping parameters that influence electronic nicotine delivery system (ENDS) emission profiles and potentially hazardous exposure levels is essential to protecting human health. We developed an automated multi-channel ENDS aerosol generation system (EAGS) for characterizing size-resolved particle emissions across pod- and mod-type devices using real-time monitoring instruments, an exposure chamber, and vaping parameters including different ventilation rates, device type and age, e-liquid formulation, and atomizer setup. Results show the ENDS device type, e-liquid flavoring, and nicotine content can affect particle emissions. In general, pod-type devices have unimodal particle size distributions and higher number emissions, while mod-type devices have bimodal size distributions and higher mass emissions. For pod-type devices, later puff fractions emit lower aerosols, which is potentially associated with the change of coil resistance and power during ageing. For a mod-type device, an atomizer with a lower resistance coil and higher power generates larger particle emissions than an atomizer with a greater resistance coil and lower power. The unventilated scenario produces higher particle emission factors, except for particle mass emission from pod-type devices. The data provided herein indicate the EAGS can produce realistic and reproducible puff profiles of pod- and mod-type ENDS devices and therefore is a suitable platform for characterizing ENDS-associated exposure risks.

Toxicological Assessment of Particulate and Metal Hazards Associated with Vaping Frequency and Device Age.

Electronic nicotine delivery systems (ENDS) aerosols are complex mixtures of chemicals, metals, and particles that may present inhalation hazards and adverse respiratory health risks. Despite being considered a safer alternative to tobacco cigarettes, metal exposure levels and respiratory effects associated with device aging and vaping frequency have not been fully characterized. In this study, we utilize an automated multi-channel ENDS aerosol generation system (EAGS) to generate aerosols from JUUL pod-type ENDS using tobacco-flavored e-liquid. Aerosol puff fractions (1-50) and (101-150) are monitored and sampled using various collection media. Extracted aerosols are prepared for metal and toxicological analysis using human primary small airway epithelial cells (SAEC). ENDS aerosol-mediated cellular responses, including reactive oxygen species (ROS), oxidative stress, cell viability, and DNA damage, are evaluated after 24 h and 7-day exposures. Our results show higher particle concentrations in later puff fractions (0.135 mg/m3) than in initial puff fractions (0.00212 mg/m3). Later puff fraction aerosols contain higher toxic metal concentrations, including chromium, copper, and lead, which elicit increased levels of ROS followed by significant declines in total glutathione and cell viability. Notably, a 30% increase in DNA damage was observed after 7 days because of later puff fraction exposures. This work is consistent with ENDS aerosols becoming more hazardous across the use of pre-filled pod devices, which may threaten respiratory health.

Oral microbiome of electronic cigarette users: A cross-sectional exploration.

OBJECTIVE: Electronic cigarettes have increased in popularity globally. Vaping may be associated with oral symptoms and pathologies including dental and periodontal damage, both of which have an underlying microbial etiology. The primary aim of this pilot study, therefore, was to compare the oral microbiome of vapers and non-vapers. SUBJECTS AND METHODS: This secondary data analysis had a cross-sectional comparative descriptive design and included data for 36 adults. Bacterial 16S rRNA genes were extracted and amplified from soft tissue oral swab specimens and taxonomically classified using the Human Oral Microbiome Database. RESULTS: Data for 18 vapers and 18 non-vapers were included in this study. Almost 56% of the vapers also smoked conventional cigarettes. Beta diversity differences were identified between vapers and non-vapers. Vapers had a significantly higher relative abundance of an unclassified species of Veillonella compared with non-vapers. Dual users had higher alpha diversity compared with exclusive vapers. Beta diversity was also associated with dual use. Multiple OTUs were identified to be associated with dual use of e-cigarettes and conventional cigarettes. CONCLUSIONS: Vapers exhibit an altered oral microbiome. Dual use of electronic cigarettes and conventional cigarettes is associated with the presence of several known pathogenic microbes.

Electronic nicotine delivery system-induced alterations in oral health via saliva assessment.

IMPACT STATEMENT: The use of traditional tobacco products is a known risk factor for the development of diseases including periodontal disease. To date, the potential oral health effects related to electronic nicotine delivery systems (ENDS) use is unknown. This study collected saliva from ENDS users and never tobacco users to examine differences in the oral cavity of inflammatory cytokines and metabolites. The identification and measurement of these ENDS-related changes provide insight into disease pathways potentially associated with ENDS use. The utilization of saliva samples collected from human participates enhances the application of the findings compared to the majority of studies using cell culture and animal models. In addition, these foundational findings can inform future studies to examining specific pathways identified, interventional approaches, and application of translatable biomarkers of ENDS use.

Induction of Oxidative DNA Damage and Epithelial Mesenchymal Transitions in Small Airway Epithelial Cells Exposed to Cosmetic Aerosols.

Engineered metal nanoparticles (ENPs) are frequently incorporated into aerosolized consumer products, known as nano-enabled products (NEPs). Concern for consumer pulmonary exposures grows as NEPs produce high concentrations of chemically modified ENPs. A significant knowledge gap still exists surrounding NEP aerosol respiratory effects as previous research focuses on pristine/unmodified ENPs. Our research evaluated metal-containing aerosols emitted from nano-enabled cosmetics and their induction of oxidative stress and DNA damage, which may contribute to epithelial mesenchymal transitions (EMT) within primary human small airway epithelial cells. We utilized an automated NEP generation system to monitor and gravimetrically collect aerosols from two aerosolized cosmetic lines. Aerosol monitoring data were inputted into modeling software to determine potential inhaled dose and in vitro concentrations. Toxicological profiles of aerosols and comparable pristine ENPs (TiO2 and Fe2O3) were used to assess reactive oxygen species and oxidative stress by fluorescent-based assays. Single-stranded DNA (ssDNA) damage and 8-oxoguanine were detected using the CometChip assay after 24-h exposure. Western blots were conducted after 21-day exposure to evaluate modulation of EMT markers. Results indicated aerosols possessed primarily ultrafine particles largely depositing in tracheobronchial lung regions. Significant increases in oxidative stress, ssDNA damage, and 8-oxoguanine were detected post-exposure to aerosols versus pristine ENPs. Western blots revealed statistically significant decreases in E-cadherin and increases in vimentin, fascin, and CD44 for two aerosols, indicating EMT. This work suggests certain prolonged NEP inhalation exposures cause oxidative DNA damage, which may play a role in cellular changes associated with reduced respiratory function and should be of concern.

Repeated pulmonary exposures to zinc ions enhance inflammatory responses to subsequent metal exposures.

AIM OF STUDY: Metal contaminants contribute to adverse human health effects via acute and chronic exposures. Acute metal exposures followed by prolonged secondary metal exposures may elicit exaggerated inflammatory responses in certain individuals. The aim of this study is to determine whether repeated pulmonary exposures to zinc chloride (ZnCl2) alter subsequent responses to zinc or cerium exposures. MATERIALS AND METHODS: Rats were intratracheally (IT) instilled with physiologic saline (n = 24) or 0.05 mg/kg ZnCl2 (n = 16) twice weekly for 4 weeks. Four days after last dosing, the saline group was divided into three subgroups, each IT-instilled with either saline, ZnCl2 or CeCl3 (both at 0.1 mg/kg). The ZnCl2 pre-instilled rats were divided into two subgroups, each instilled with 0.1 mg/kg ZnCl2 or CeCl3. Biomarkers of lung injury/inflammation were assessed in bronchoalveolar lavage (BAL) fluid collected 24 hours later. Oxidative stress was evaluated as total and reduced glutathione in BAL. RESULTS: Increases in inflammatory cells, LDH, albumin, leptin, MCP-1, IP-10, fractalkine, TNFα and RANTES were observed in rats instilled with multiple PBS and then with 0.1 mg/kg ZnCl2 and CeCl3. However, rats pre-exposed repeatedly to 0.05 mg/kg ZnCl2 and then challenged with 0.1 mg/kg ZnCl2 or CeCl3 showed even more eosinophils, lymphocytes, and increased concentrations of hemoglobin and MIP-1α. Significant reduction in GSH/GSSG ratios in BAL in response to all ZnCl2 or CeCl3 exposures indicated oxidative stress. CONCLUSION: Previous exposure to zinc ions increases responsiveness to subsequent exposures to zinc and cerium ions. These findings suggest enhanced sensitization possibly due to a reduction in antioxidant defenses.

Nanofiller Presence Enhances Polycyclic Aromatic Hydrocarbon (PAH) Profile on Nanoparticles Released during Thermal Decomposition of Nano-enabled Thermoplastics: Potential Environmental Health Implications.

Nano-enabled products are ultimately destined to reach end-of-life with an important fraction undergoing thermal degradation through waste incineration or accidental fires. Although previous studies have investigated the physicochemical properties of released lifecycle particulate matter (called LCPM) from thermal decomposition of nano-enabled thermoplastics, critical questions about the effect of nanofiller on the chemical composition of LCPM still persist. Here, we investigate the potential nanofiller effects on the profiles of 16 Environmental Protection Agency (EPA)-priority polycyclic aromatic hydrocarbons (PAHs) adsorbed on LCPM from thermal decomposition of nano-enabled thermoplastics. We found that nanofiller presence in thermoplastics significantly enhances not only the total PAH concentration in LCPM but most importantly also the high molecular weight (HMW, 4-6 ring) PAHs that are considerably more toxic than the low molecular weight (LMW, 2-3 ring) PAHs. This nano-specific effect was also confirmed during in vitro cellular toxicological evaluation of LCPM for the case of polyurethane thermoplastic enabled with carbon nanotubes (PU-CNT). LCPM from PU-CNT shows significantly higher cytotoxicity compared to PU which could be attributed to its higher HMW PAH concentration. These findings are crucial and make the case that nanofiller presence in thermoplastics can significantly affect the physicochemical and toxicological properties of LCPM released during thermal decomposition.

Toxicological Implications of Released Particulate Matter during Thermal Decomposition of Nano-Enabled Thermoplastics.

Nano-enabled thermoplastics are part of the growing market of nano-enabled products (NEPs) that have vast utility in several industries and consumer goods. The use and disposal of NEPs at their end of life has raised concerns about the potential release of constituent engineered nanomaterials (ENMs) during thermal decomposition and their impact on environmental health and safety. To investigate this issue, industrially relevant nano-enabled thermoplastics including polyurethane, polycarbonate, and polypropylene containing carbon nanotubes (0.1 and 3% w/v, respectively), polyethylene containing nanoscale iron oxide (5% w/v), and ethylene vinyl acetate containing nanoscale titania (2 and 5% w/v) along with their pure thermoplastic matrices were thermally decomposed using the recently developed lab based Integrated Exposure Generation System (INEXS). The life cycle released particulate matter (called LCPM) was monitored using real time instrumentation, size fractionated, sampled, extracted and prepared for toxicological analysis using primary small airway epithelial cells to assess potential toxicological effects. Various cellular assays were used to assess reactive oxygen species and total glutathione as measurements of oxidative stress along with mitochondrial function, cellular viability, and DNA damage. By comparing toxicological profiles of LCPM released from polymer only (control) with nano-enabled LCPM, potential nanofiller effects due to the use of ENMs were determined. We observed associations between NEP properties such as the percent nanofiller loading, host matrix, and nanofiller chemical composition and the physico-chemical properties of released LCPM, which were linked to biological outcomes. More specifically, an increase in percent nanofiller loading promoted a toxicological response independent of increasing LCPM dose. Importantly, differences in host matrix and nanofiller composition were shown to enhance biological activity and toxicity of LCPM. This work highlights the importance of assessing the toxicological properties of LCPM and raises environmental health and safety concerns of nano-enabled products at their end of life during thermal decomposition/incineration.

Emerging metrology for high-throughput nanomaterial genotoxicology.

The rapid development of the engineered nanomaterial (ENM) manufacturing industry has accelerated the incorporation of ENMs into a wide variety of consumer products across the globe. Unintentionally or not, some of these ENMs may be introduced into the environment or come into contact with humans or other organisms resulting in unexpected biological effects. It is thus prudent to have rapid and robust analytical metrology in place that can be used to critically assess and/or predict the cytotoxicity, as well as the potential genotoxicity of these ENMs. Many of the traditional genotoxicity test methods [e.g. unscheduled DNA synthesis assay, bacterial reverse mutation (Ames) test, etc.,] for determining the DNA damaging potential of chemical and biological compounds are not suitable for the evaluation of ENMs, due to a variety of methodological issues ranging from potential assay interferences to problems centered on low sample throughput. Recently, a number of sensitive, high-throughput genotoxicity assays/platforms (CometChip assay, flow cytometry/micronucleus assay, flow cytometry/γ-H2AX assay, automated 'Fluorimetric Detection of Alkaline DNA Unwinding' (FADU) assay, ToxTracker reporter assay) have been developed, based on substantial modifications and enhancements of traditional genotoxicity assays. These new assays have been used for the rapid measurement of DNA damage (strand breaks), chromosomal damage (micronuclei) and for detecting upregulated DNA damage signalling pathways resulting from ENM exposures. In this critical review, we describe and discuss the fundamental measurement principles and measurement endpoints of these new assays, as well as the modes of operation, analytical metrics and potential interferences, as applicable to ENM exposures. An unbiased discussion of the major technical advantages and limitations of each assay for evaluating and predicting the genotoxic potential of ENMs is also provided.