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King BM, Janechek NJ, Bryngelson N, Adamcakova-Dodd A, Lersch T, Bunker K, Casuccio G, Thorne PS, Stanier CO, Fiegel J. Lung cell exposure to secondary photochemical aerosols generated from OH oxidation of cyclic siloxanes. CHEMOSPHERE 2020; 241:125126. [PMID: 31683444 PMCID: PMC6941482 DOI: 10.1016/j.chemosphere.2019.125126] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/30/2019] [Revised: 10/13/2019] [Accepted: 10/14/2019] [Indexed: 06/10/2023]
Abstract
To study the fate of cyclic volatile methyl siloxanes (cVMS) undergoing photooxidation in the environment and to assess the acute toxicity of inhaled secondary aerosols from cVMS, we used an oxidative flow reactor (OFR) to produce aerosols from oxidation of decamethylcyclopentasiloxane (D5). The aerosols produced from this process were characterized for size, shape, and chemical composition. We found that the OFR produced aerosols composed of silicon and oxygen, arranged in chain agglomerates, with primary particles of approximately 31 nm in diameter. Lung cells were exposed to the secondary organosilicon aerosols at estimated doses of 54-116 ng/cm2 using a Vitrocell air-liquid interface system, and organic gases and ozone exposure was minimized through a series of denuders. Siloxane aerosols were not found to be highly toxic.
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Parizek NJ, Steines BR, Haque E, Altmaier R, Adamcakova-Dodd A, O’Shaughnessy PT, Thorne PS. Acute in vivo pulmonary toxicity assessment of occupationally relevant particulate matter from a cellulose nanofiber board. NANOIMPACT 2020; 17:100210. [PMID: 32968699 PMCID: PMC7504912 DOI: 10.1016/j.impact.2020.100210] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Cellulose nanofibers (CNFs) are an emerging engineered nanomaterial that are utilized in a variety of applications, including as a replacement for urea-formaldehyde, and other adhesives, as the binding agent in manufactured fiber and particle boards. To ensure the health and well-being of those producing, installing, or otherwise using cellulose nanofiber boards (CNFBs) it is imperative that the particulate matter (PM) produced during CNFB manipulation be evaluated for toxicity. We developed and internally verified a generation system to examine the PM produced by sanding CNFB using aluminum oxide sandpaper. With 80-grit sandpaper our system produced a low dispersity aerosol, as determined by a scanning mobility particle sizer and an optical particle counter, with a geometric mean of 28 nm (GSD = 1.60). ICP-MS evaluation showed little difference in metal concentrations between CNFB PM and nonsanded CNFB stock. We then used the system to simultaneously generate and expose both male and female C57BL/6J mice acutely for 4 hours at a concentration of 7.9 mg/m3. Sham-exposed controls were treated similarly but without sanding the CNFB. Analysis of bronchoalveolar lavage (BAL) fluid biomarkers showed no signs of inflammatory response at either 4- or 24-hours post exposure. Further, BAL cell viability, number of total cells, and pulmonary cellular recruitment were not significantly changed between the sham-exposed controls and CNFB-exposed mice. Histology further confirmed no pulmonary toxicity as a result of CNFB PM inhalation. We conclude that inhalation of a high concentration of the PM from manipulation of a CNFB did not produce acute toxic responses within 24 hours of exposure.
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Mendy A, Metwali N, Perry SS, Chrischilles EA, Wang K, Thorne PS. Household endotoxin reduction in the Louisa Environmental Intervention Project for rural childhood asthma. INDOOR AIR 2020; 30:88-97. [PMID: 31605641 PMCID: PMC7889405 DOI: 10.1111/ina.12610] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/21/2018] [Revised: 09/09/2019] [Accepted: 10/07/2019] [Indexed: 06/10/2023]
Abstract
Endotoxin exacerbates asthma. We designed the Louisa Environmental Intervention Project (LEIP) and assessed its effectiveness in reducing household endotoxin and improving asthma symptoms in rural Iowa children. Asthmatic school children (N = 104 from 89 homes) of Louisa and Keokuk counties in Iowa (aged 5-14 years) were recruited and block-randomized to receive extensive (education + professional cleaning) or educational interventions. Environmental sampling collection and respiratory survey administration were done at baseline and during three follow-up visits. Mixed-model analyses were used to assess the effect of the intervention on endotoxin levels and asthma symptoms in the main analysis and of endotoxin reduction on asthma symptoms in exploratory analysis. In the extensive intervention group, dust endotoxin load was significantly reduced in post-intervention visits. The extensive compared with the educational intervention was associated with significantly decreased dust endotoxin load in farm homes and less frequent nighttime asthma symptoms. In exploratory analysis, dust endotoxin load reduction from baseline was associated with lower total asthma symptoms score (Odds ratio: 0.52, 95% confidence interval: 0.29-0.92). In conclusion, the LEIP intervention reduced household dust endotoxin and improved asthma symptoms. However, endotoxin reductions were not sustained post-intervention by residents.
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Hwang J, Golla V, Metwali N, Thorne PS. Inhalable and Respirable Particulate and Endotoxin Exposures in Kentucky Equine Farms. J Agromedicine 2019; 25:179-189. [PMID: 31430228 DOI: 10.1080/1059924x.2019.1656128] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Adverse respiratory health effects in the agricultural industry have been linked to particulate endotoxin exposure. However, whether the endotoxin concentration is significantly correlated to the size of the particle remains an open question. To date, limited research has been conducted to assess particulate endotoxin exposures in the agricultural industry in general or the equine industry in particular. A task-based exposure assessment was conducted to characterize the endotoxin levels of inhalable and respirable particles on four Kentucky farms during the summer season. We conducted personal sampling of respirable and inhalable particles (n = 75) across all four farms and particulate endotoxin (n = 58) on two of them. Simultaneously, we collected real-time area samples across all four farms by task - horse care, filing hooves, cleaning stalls, cleaning barns, cleaning dry lots, and cleaning trucks. The endotoxin concentration of inhalable particles (geometric mean: 50.2-1,024 EU/m3) was ~50 times higher than that of respirable particles (geometric mean: 1.72-19.0 EU/m3). Horse care generated the lowest endotoxin concentrations for both particle sizes, while cleaning tasks tended to produce higher concentrations. There was no significant correlation between the endotoxin and particle concentrations for each size fraction based on tasks by farm (R2 = 0.069 for inhalable; 0.214 for respirable). The equine workers in this study were exposed to higher endotoxin concentrations than workers in other industries, such as the swine industry. Providing exposure control guidelines and recommendations to the equine industry is necessary to reduce long-term endotoxin exposure and to prevent adverse respiratory symptoms.
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Dawson JB, Galvin K, Thorne PS, Rohlman DS. Organophosphorus pesticide residue levels in homes located near orchards. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2018; 15:847-856. [PMID: 30138040 PMCID: PMC6372327 DOI: 10.1080/15459624.2018.1515489] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/30/2018] [Revised: 07/10/2018] [Accepted: 08/20/2018] [Indexed: 06/08/2023]
Abstract
Organophosphorus pesticides (OPs) are commonly applied to agricultural crops. Families living in these communities may have higher exposure to OPs due to take home exposures and close proximity to agricultural fields. The objectives of this study were to measure OP concentrations in home carpet dust in agricultural and non-agricultural households and examine factors that may impact OP concentrations such as occupation, housing characteristics, and resident behaviors. Agricultural households had at least one parent who worked in agriculture during the previous 5 years. Carpet dust samples were collected at two time points from 278 households in an agricultural community located in the Pacific Northwest from 2008-2011. Samples were analyzed for four types of OPs: azinphos-methyl, phosmet, malathion, and chlorpyrifos. Overall, OP detection frequencies and concentrations were higher in agricultural households compared to non-agricultural households. Factors associated with higher OP concentrations in home carpet dust were identified and included: (1) homes with two or more agricultural workers living in the home, (2) homes located in close proximity to an agricultural field or orchard, (3) having an entry floor mat, and (4) frequently vacuuming the house. Having air conditioning in the home had a protective effect with OP concentrations. While the use of these four OPs is restricted or limited for residential use in the United States, results show that they were still found in the indoor environment. The understanding of the impact of agricultural work and other factors that elevate levels of OPs in the home is crucial to mitigating pesticide exposure in agricultural communities.
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Metwali A, Thorne PS, Ince MN, Metwali N, Winckler S, Guan X, Beyatli S, Truscott J, Urban JF, Elliott DE. Recirculating Immunocompetent Cells in Colitic Mice Intensify Their Lung Response to Bacterial Endotoxin. Dig Dis Sci 2018; 63:2930-2939. [PMID: 30022451 PMCID: PMC6182434 DOI: 10.1007/s10620-018-5196-z] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/25/2017] [Accepted: 07/03/2018] [Indexed: 12/17/2022]
Abstract
BACKGROUND Patients with inflammatory bowel disease have higher incidence of airway hyperresponsiveness compared to the general population. Lung inflammation leading to airway hyperresponsiveness causes illnesses for more than ten percent of the population in USA. AIMS We investigated the lung response to bacterial endotoxin in colitic mice. METHODS Rag-1 mice were transplanted with negatively selected splenic T cells. Some mice groups were treated with NSAID to develop colitis. All mice were treated with bacterial endotoxin and necropsied 3 weeks later. RESULTS Colitic mice developed intensified lung inflammation on day 21 of treatment with bacterial endotoxin. Pulmonary lymphocytes from colitic mice displayed a proinflammatory cytokine profile, expressed high ICAM1 and low FoxP3. CD11c+, CD8+ cells bound and responded to non-systemic antigens from gut-localized microbiota and had higher expression of TLR4. CONCLUSIONS Colitic mice developed exacerbated lung inflammation in response to bacterial endotoxin compared to non-colitic mice. Proinflammatory cytokines from pulmonary lymphocytes induced high expression of ICAM1 and suppressed FoxP3 on CD4+ cells. CD11c+, CD8+ cells binding and responding to gut-localized antigens as well as high expression of TLR4 indicate innate and adaptive lung response to bacterial endotoxin. Inflammatory cells from colons of colitic mice homed in the lungs as well as the intestine suggesting recirculation of sensitized immunocompetent cells. These data support our hypothesis that colitis intensifies lung inflammation.
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Clippinger AJ, Allen D, Behrsing H, BéruBé KA, Bolger MB, Casey W, DeLorme M, Gaça M, Gehen SC, Glover K, Hayden P, Hinderliter P, Hotchkiss JA, Iskandar A, Keyser B, Luettich K, Ma-Hock L, Maione AG, Makena P, Melbourne J, Milchak L, Ng SP, Paini A, Page K, Patlewicz G, Prieto P, Raabe H, Reinke EN, Roper C, Rose J, Sharma M, Spoo W, Thorne PS, Wilson DM, Jarabek AM. Pathway-based predictive approaches for non-animal assessment of acute inhalation toxicity. Toxicol In Vitro 2018; 52:131-145. [PMID: 29908304 PMCID: PMC6760245 DOI: 10.1016/j.tiv.2018.06.009] [Citation(s) in RCA: 52] [Impact Index Per Article: 8.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2018] [Revised: 06/01/2018] [Accepted: 06/08/2018] [Indexed: 01/14/2023]
Abstract
New approaches are needed to assess the effects of inhaled substances on human health. These approaches will be based on mechanisms of toxicity, an understanding of dosimetry, and the use of in silico modeling and in vitro test methods. In order to accelerate wider implementation of such approaches, development of adverse outcome pathways (AOPs) can help identify and address gaps in our understanding of relevant parameters for model input and mechanisms, and optimize non-animal approaches that can be used to investigate key events of toxicity. This paper describes the AOPs and the toolbox of in vitro and in silico models that can be used to assess the key events leading to toxicity following inhalation exposure. Because the optimal testing strategy will vary depending on the substance of interest, here we present a decision tree approach to identify an appropriate non-animal integrated testing strategy that incorporates consideration of a substance's physicochemical properties, relevant mechanisms of toxicity, and available in silico models and in vitro test methods. This decision tree can facilitate standardization of the testing approaches. Case study examples are presented to provide a basis for proof-of-concept testing to illustrate the utility of non-animal approaches to inform hazard identification and risk assessment of humans exposed to inhaled substances.
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Newton AN, Davis M, Koehler K, Shreffler W, Ahluwalia S, Metwali N, Thorne PS, Paigen BJ, Matsui EC. Atopy as a Modifier of the Relationships Between Endotoxin Exposure and Symptoms Among Laboratory Animal Workers. Ann Work Expo Health 2018; 61:1024-1028. [PMID: 29028247 DOI: 10.1093/annweh/wxx061] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/26/2016] [Accepted: 06/30/2017] [Indexed: 01/13/2023] Open
Abstract
Background Exposure to endotoxin is known to trigger airway inflammation and symptoms, and atopy may modify the relationship between endotoxin exposure and symptom development. Objective To test the a priori hypothesis that atopic status modifies the relationship between endotoxin exposure and respiratory symptom development. Methods A prospective study of laboratory workers at The Jackson Laboratories was conducted. Allergy skin testing was performed and population demographic and clinical information was obtained at baseline. Personal exposure assessments for airborne endotoxin and surveys of self-reported symptoms were performed every 6 months. Cox proportional hazards models were used to examine the relationship between endotoxin exposure and development of mouse-associated symptoms and multivariate regression was used to test for interaction. Results Overall, 16 (9%) of 174 worker-participants developed mouse-associated rhinoconjunctivitis symptoms by 24 months and 8 (5%) developed mouse-associated lower respiratory symptoms by 24 months. Among workers with endotoxin exposure above the median (≥2.4 EU m-3), 5 (6% of 80) atopics reported mouse-associated rhinoconjunctivitis symptoms at 24 months as compared to 3 (3% of 94) non-atopics. Among workers below the median endotoxin exposure (<2.4 EU m-3), 1 (1% of 80) atopic reported mouse-associated rhinoconjunctivitis symptoms at 24 months as compared to 7 (7% of 94) non-atopics. For the combination of symptoms, the adjusted hazard ratio was 6.8 (95% confidence interval: 0.7-67.2) for atopics and 0.07 (95% confidence interval: 0.01-0.5) for non-atopics. Conclusion In this occupational cohort, atopic workers may be more susceptible to, and non-atopic workers protected from, endotoxin-associated upper and lower respiratory symptoms.
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Lee MK, Carnes MU, Butz N, Azcarate-Peril MA, Richards M, Umbach DM, Thorne PS, Beane Freeman LE, Peddada SD, London SJ. Exposures Related to House Dust Microbiota in a U.S. Farming Population. ENVIRONMENTAL HEALTH PERSPECTIVES 2018; 126:067001. [PMID: 29863827 PMCID: PMC6084882 DOI: 10.1289/ehp3145] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/22/2017] [Revised: 05/01/2018] [Accepted: 05/02/2018] [Indexed: 05/09/2023]
Abstract
BACKGROUND Environmental factors can influence the house dust microbiota, which may impact health outcomes. Little is known about how farming exposures impact the indoor microbiota. OBJECTIVE We aimed to identify exposures related to bacterial communities in house dust in a U.S. farming population. METHODS We used 16S rRNA amplicon sequencing to characterize bacterial communities in vacuumed dust samples from the bedrooms of a subset of 879 households of farmers and farmers' spouses enrolled in the Agricultural Lung Health Study (ALHS), a case-control study of asthma nested within the Agricultural Health Study (AHS) in North Carolina and Iowa. Information on current farming (past 12 mo), including both crop and animal farming, and other potential microbial sources was obtained via questionnaires. We used linear regression to evaluate associations between exposures and bacterial diversity within each sample, analysis of similarity (ANOSIM), and permutational multivariate analysis of variance (PERMANOVA) to identify exposures related to diversity between samples, and analysis of composition of microbiome to examine whether exposures related to diversity were also related to differential abundance of specific operational taxonomic units (OTUs). RESULTS Current farming was positively associated with bacterial diversity in house dust, with or without adjustment for nonfarm exposures related to diversity, including presence of indoor pets, home condition, and season of dust collection. Many taxa exhibited differential abundance related to farming. Some taxa in the phyla Chloroflexi and Verrucomicrobia were associated [false discovery rate (FDR)<0.05] with farming but not with other nonfarm factors. Many taxa correlated with the concentration of house dust of endotoxin, commonly studied as a general marker of exposure to the farming environment. CONCLUSIONS In this farming population, house dust microbiota differed by current farming status. Understanding the determinants of the indoor microbiota is the first step toward understanding potential relationships with health outcomes. https://doi.org/10.1289/EHP3145.
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Lynch TJ, Anderson PJ, Rotti PG, Tyler SR, Crooke AK, Choi SH, Montoro DT, Silverman CL, Shahin W, Zhao R, Jensen-Cody CW, Adamcakova-Dodd A, Evans TIA, Xie W, Zhang Y, Mou H, Herring BP, Thorne PS, Rajagopal J, Yeaman C, Parekh KR, Engelhardt JF. Submucosal Gland Myoepithelial Cells Are Reserve Stem Cells That Can Regenerate Mouse Tracheal Epithelium. Cell Stem Cell 2018; 22:779. [PMID: 29727685 DOI: 10.1016/j.stem.2018.04.007] [Citation(s) in RCA: 28] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Lynch TJ, Anderson PJ, Rotti PG, Tyler SR, Crooke AK, Choi SH, Montoro DT, Silverman CL, Shahin W, Zhao R, Jensen-Cody CW, Adamcakova-Dodd A, Evans TIA, Xie W, Zhang Y, Mou H, Herring BP, Thorne PS, Rajagopal J, Yeaman C, Parekh KR, Engelhardt JF. Submucosal Gland Myoepithelial Cells Are Reserve Stem Cells That Can Regenerate Mouse Tracheal Epithelium. Cell Stem Cell 2018; 22:653-667.e5. [PMID: 29656941 DOI: 10.1016/j.stem.2018.03.017] [Citation(s) in RCA: 66] [Impact Index Per Article: 11.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/17/2017] [Revised: 01/25/2018] [Accepted: 03/21/2018] [Indexed: 12/18/2022]
Abstract
The mouse trachea is thought to contain two distinct stem cell compartments that contribute to airway repair-basal cells in the surface airway epithelium (SAE) and an unknown submucosal gland (SMG) cell type. Whether a lineage relationship exists between these two stem cell compartments remains unclear. Using lineage tracing of glandular myoepithelial cells (MECs), we demonstrate that MECs can give rise to seven cell types of the SAE and SMGs following severe airway injury. MECs progressively adopted a basal cell phenotype on the SAE and established lasting progenitors capable of further regeneration following reinjury. MECs activate Wnt-regulated transcription factors (Lef-1/TCF7) following injury and Lef-1 induction in cultured MECs promoted transition to a basal cell phenotype. Surprisingly, dose-dependent MEC conditional activation of Lef-1 in vivo promoted self-limited airway regeneration in the absence of injury. Thus, modulating the Lef-1 transcriptional program in MEC-derived progenitors may have regenerative medicine applications for lung diseases.
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Stapleton EM, O’Shaughnessy PT, Locke SJ, Altmaier RW, Hofmann JN, Beane Freeman LE, Thorne PS, Jones RR, Friesen MC. A task-based analysis of black carbon exposure in Iowa farmers during harvest. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2018; 15:293-304. [PMID: 29286870 PMCID: PMC6114936 DOI: 10.1080/15459624.2017.1422870] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/17/2023]
Abstract
Diesel exhaust has been associated with adverse human health effects. Farmers are often exposed to diesel exhaust; however, their diesel exposure has not been well characterized. In this descriptive study, we measured black carbon concentrations as a proxy for diesel exhaust exposure in 16 farmers over 20 sampling days during harvest in southeast Iowa. Farmers wore a personal aethalometer which measured real-time black carbon levels throughout the working day, and their activities were recorded by a field researcher. Black carbon concentrations were characterized for each farmer, and by activity, vehicle fuel type, and microenvironment. Overall, 574 discrete tasks were monitored with a median task duration of 5.5 min. Of these tasks, 39% involved the presence of a diesel vehicle. Farmers' daily black carbon geometric mean exposures ranged from 0.1-2.3 µg/m3, with a median daily geometric mean of 0.3 µg/m3. The highest black carbon concentrations were measured on farmers who used or worked near diesel vehicles (geometric mean ranged from 0.5 µg/m3 while harvesting to 4.9 µg/m3 during animal work). Higher geometric means were found for near vs. far proximity to diesel-fueled vehicles and equipment (2.9 vs. 0.3 µg/m3). Indoor, bystander proximity to diesel-operated vehicles resulted in the highest geometric mean black carbon concentrations (18 µg/m3). Use of vehicles with open cabs had higher mean black carbon concentrations than closed cabs (2.1-3.2 vs. 0.4-0.9 µg/m3). In summary, our study provided evidence that farmers were frequently exposed to black carbon associated with diesel-related activities at levels above urban ambient concentrations in their daily work during harvest.
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Mendy A, Salo PM, Cohn RD, Wilkerson J, Zeldin DC, Thorne PS. House Dust Endotoxin Association with Chronic Bronchitis and Emphysema. ENVIRONMENTAL HEALTH PERSPECTIVES 2018; 126:037007. [PMID: 29578323 PMCID: PMC6071737 DOI: 10.1289/ehp2452] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/04/2017] [Revised: 01/30/2018] [Accepted: 01/31/2018] [Indexed: 05/15/2023]
Abstract
BACKGROUND Endotoxin has been reported to be associated with chronic bronchitis or emphysema (CBE) at high occupational exposures. However, whether levels found in domestic environments have similar effects is unknown. OBJECTIVES We aimed to study the association between house dust endotoxin and CBE in a sample representative of the U.S. population. METHODS We analyzed data from 3,393 participants ≥20 y old from the National Health and Nutrition Examination Survey (NHANES) 2005-2006. House dust from bedding and from bedroom floors was analyzed for endotoxin content. NHANES participants received questionnaires and underwent examination as well as extensive laboratory testing. Logistic regression was used to examine the association of endotoxin levels with CBE diagnosis and symptoms, adjusting for covariates. The survey design and weights were applied so that estimates were nationally representative and so that statistical inferences were made appropriately. RESULTS The median endotoxin concentration in house dust was 14.61 EU/mg dust, and CBE was reported by 8.2% of participants. In the adjusted analysis, one unit (EU/mg) increase in log10-transformed endotoxin concentrations was associated with a 27% increase in the odds of CBE diagnosis [OR=1.27 (95% CI: 1.00, 1.61)] and a 78% increase in the odds of chronic bronchitis symptoms (defined as cough and phlegm for ≥3 mo in a year for ≥2 y) [OR=1.78 (95% CI: 1.01, 3.12)]. Sensitization to inhalant allergens (p=0.001) modified the relationship between endotoxin and CBE diagnosis, with stronger associations observed in sensitized participants [OR=2.46 (95% CI: 1.72, 3.50) for a unit increase in log10-endotoxin]. CONCLUSIONS In a population-based sample of U.S. adults, endotoxin levels in homes were associated with a self-reported history of CBE diagnosis and chronic bronchitis symptoms, with stronger associations among people sensitized to inhalant allergens. https://doi.org/10.1289/EHP2452.
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Mendy A, Wilkerson J, Salo PM, Cohn RD, Zeldin DC, Thorne PS. Endotoxin predictors and associated respiratory outcomes differ with climate regions in the U.S. ENVIRONMENT INTERNATIONAL 2018; 112:218-226. [PMID: 29277065 PMCID: PMC5899028 DOI: 10.1016/j.envint.2017.12.003] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 09/19/2017] [Revised: 12/01/2017] [Accepted: 12/01/2017] [Indexed: 05/24/2023]
Abstract
RATIONALE Although endotoxin is a recognized cause of environmental lung disease, how its relationship with respiratory outcomes varies with climate is unknown. OBJECTIVE To examine the endotoxin predictors as well as endotoxin association with asthma, wheeze, and sensitization to inhalant allergens in various US climate regions. METHODS We analyzed data on 6963 participants in the National Health and Nutrition Examination Survey. Endotoxin measurements of house dust from bedroom floor and bedding were performed at the University of Iowa. Linear and logistic regression analyses were used to identify endotoxin predictors and assess endotoxin association with health outcomes. RESULTS The overall median house dust endotoxin was 16.2 EU/mg; it was higher in mixed-dry/hot-dry regions (19.7 EU/mg) and lower in mixed-humid/marine areas (14.8 EU/mg). Endotoxin predictors and endotoxin association with health outcomes significantly differed across climate regions. In subarctic/very cold/cold regions, log10-endotoxin was significantly associated with higher prevalence of wheeze outcomes (OR:1.48, 95% CI:1.19-1.85 for any wheeze, OR:1.48, 95% CI:1.22-1.80 for exercise-induced wheeze, OR:1.50, 95% CI:1.13-1.98 for prescription medication for wheeze, and OR:1.95, 95% CI:1.50-2.54 for doctor/ER visit for wheeze). In hot-humid regions, log10-endotoxin was positively associated with any wheeze (OR:1.66, 95% CI:1.04-2.65) and current asthma (OR:1.56, 95% CI:1.11-2.18), but negatively with sensitization to any inhalant allergens (OR:0.83, 95% CI:0.74-0.92). CONCLUSION Endotoxin predictors and endotoxin association with asthma and wheeze differ across U.S. climate regions. Endotoxin is associated positively with wheeze or asthma in cold and hot-humid regions, but negatively with sensitization to inhalant allergens in hot-humid climates.
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Sweeney S, Adamcakova-Dodd A, Thorne PS, Assouline JG. Multifunctional nanoparticles for real-time evaluation of toxicity during fetal development. PLoS One 2018; 13:e0192474. [PMID: 29420606 PMCID: PMC5805299 DOI: 10.1371/journal.pone.0192474] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2017] [Accepted: 01/24/2018] [Indexed: 01/10/2023] Open
Abstract
Increasing production of nanomaterials in industrial quantities has led to public health concerns regarding exposure, particularly among pregnant women and developing fetuses. Information regarding the barrier capacity of the placenta for various nanomaterials is limited due to challenges working with ex vivo human placentas or in vivo animal models. To facilitate real-time in vivo imaging of placental transport, we have developed a novel, multifunctional nanoparticle, based on a core of mesoporous silica nanoparticles (MSN), and functionalized for magnetic resonance imaging (MRI), ultrasound, and fluorescent microscopy. Our MSN particles were tested as a tracking method for harmful and toxic nanomaterials. In gravid mice, intravenous injections of MSN were administered in the maternal circulation in early gestation (day 9) and late gestation (day 14). MRI and ultrasound were used to track the MSN following the injections. Changes in contrast relative to control mice indicated that MSN were observed in the embryos of mice following early gestation injections, while MSN were excluded from the embryo by the placenta following late gestation injections. The timing of transplacental barrier porosity is consistent with the notion that in mice there is a progressive increasing segregation by the placenta in later gestation. In addition, built-in physico-chemical properties of our MSN may present options for the therapeutic treatment of embryonic exposure. For example, if preventive measures such as detoxification of harmful compounds are implemented, the particle size and exposure timing can be tailored to selectively distribute to the maternal side of the trophoblast or delivered to the fetus.
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Peters TM, O'Shaughnessy PT, Grant R, Altmaier R, Swanton E, Falk J, Osterberg D, Parker E, Wyland NG, Sousan S, Stark AL, Thorne PS. Community airborne particulate matter from mining for sand used as hydraulic fracturing proppant. THE SCIENCE OF THE TOTAL ENVIRONMENT 2017; 609:1475-1482. [PMID: 28800690 PMCID: PMC5600868 DOI: 10.1016/j.scitotenv.2017.08.006] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/06/2017] [Revised: 07/31/2017] [Accepted: 08/01/2017] [Indexed: 06/07/2023]
Abstract
Field and laboratory studies were conducted to evaluate the impact of proppant sand mining and processing activities on community particulate matter (PM) concentrations. In field studies outside 17 homes within 800m of sand mining activities (mining, processing, and transport), respirable (PM4) crystalline silica concentrations were low (<0.4μg/m3) with crystalline silica detected on 7 samples (2% to 4% of mass). In long-term monitoring at 6 homes within 800m of sand mining activities, the highest daily mean PM concentrations observed were 14.5μg/m3 for PM2.5 and 37.3μg/m3 for PM10, although infrequent (<3% of time), short-term elevated PM concentrations occurred when wind blew over the facility. In laboratory studies, aerosolized sand was shown to produce respirable-sized particles, containing 6% to 19% crystalline silica. Dispersion modeling of a mine and processing facility indicated that PM10 can exceed standards short distances (<40m) beyond property lines. Lastly, fence-line PM and crystalline silica concentrations reported to state agencies were substantially below regulatory or guideline values, although several excursions were observed for PM10 when winds blew over the facility. Taken together, community exposures to airborne particulate matter from proppant sand mining activities at sites similar to these appear to be unlikely to cause chronic adverse health conditions.
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Salo PM, Wilkerson J, Rose KM, Cohn RD, Calatroni A, Mitchell HE, Sever ML, Gergen PJ, Thorne PS, Zeldin DC. Bedroom allergen exposures in US households. J Allergy Clin Immunol 2017; 141:1870-1879.e14. [PMID: 29198587 DOI: 10.1016/j.jaci.2017.08.033] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2016] [Revised: 08/16/2017] [Accepted: 08/28/2017] [Indexed: 10/18/2022]
Abstract
BACKGROUND Bedroom allergen exposures contribute to allergic disease morbidity because people spend considerable time in bedrooms, where they come into close contact with allergen reservoirs. OBJECTIVE We investigated participant and housing characteristics, including sociodemographic, regional, and climatic factors, associated with bedroom allergen exposures in a nationally representative sample of the US population. METHODS Data were obtained from National Health and Nutrition Examination Survey 2005-2006. Information on participant and housing characteristics was collected by using questionnaires and environmental assessments. Concentrations of 8 indoor allergens (Alt a 1, Bla g 1, Can f 1, Fel d 1, Der f 1, Der p 1, Mus m 1, and Rat n 1) in dust vacuumed from nearly 7000 bedrooms were measured by using immunoassays. Exposure levels were classified as increased based on percentile (75th/90th) cutoffs. We estimated the burden of exposure to multiple allergens and used multivariable logistic regression to identify independent predictors for each allergen and household allergen burden. RESULTS Almost all participants (>99%) had at least 1 and 74.2% had 3 to 6 allergens detected. More than two thirds of participants (72.9%) had at least 1 allergen and 18.2% had 3 or more allergens exceeding increased levels. Although exposure variability showed significant racial/ethnic and regional differences, high exposure burden to multiple allergens was most consistently associated with the presence of pets and pests, living in mobile homes/trailers and older and rental homes, and living in nonmetropolitan areas. CONCLUSIONS Exposure to multiple allergens is common. Despite highly variable exposures, bedroom allergen burden is strongly associated with the presence of pets and pests.
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D'Souza JC, Kawut SM, Elkayam LR, Sheppard L, Thorne PS, Jacobs DR, Bluemke DA, Lima JAC, Kaufman JD, Larson TV, Adar SD. Ambient Coarse Particulate Matter and the Right Ventricle: The Multi-Ethnic Study of Atherosclerosis. ENVIRONMENTAL HEALTH PERSPECTIVES 2017; 125:077019. [PMID: 28760719 PMCID: PMC5744657 DOI: 10.1289/ehp658] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/14/2016] [Revised: 02/24/2017] [Accepted: 03/16/2017] [Indexed: 05/24/2023]
Abstract
BACKGROUND Coarse particulate matter (P10-2.5) is primarily mechanically generated and includes crustal material, brake and tire wear, and biological particles. PM10-2.5 is associated with pulmonary disease, which can lead to right ventricular (RV) dysfunction. Although RV characteristics have been associated with combustion-related pollutants, relationships with PM10-2.5 remain unknown. OBJECTIVES To quantify cross-sectional associations between RV dysfunction and PM10-2.5 mass and components among older adults and susceptible populations. METHODS We used baseline cardiac magnetic resonance images from 1,490 participants (45-84 y old) from the Multi-Ethnic Study of Atherosclerosis and assigned 5-y residential concentrations of PM10-2.5 mass, copper, zinc, phosphorus, silicon, and endotoxin, using land-use regression models. We quantified associations with RV mass, end-diastolic volume, and ejection fraction after control for risk factors and copollutants using linear regression. We further examined personal susceptibility. RESULTS We found positive associations of RV mass and, to a lesser extent, end diastolic volume with PM10-2.5 mass among susceptible populations including smokers and persons with emphysema. After adjustment for copollutants, an interquartile range increase in PM10-2.5 mass (2.2 μg/m3) was associated with 0.5 g (95% CI: 0.0, 1.0), 0.9 g (95% CI: 0.1, 1.7), and 1.4 g (95% CI: 0.4, 2.5) larger RV mass among former smokers, current smokers, and persons with emphysema, respectively. No associations were found with healthy individuals or with ejection fraction. CONCLUSIONS Alterations to RV structure may represent a mechanism by which long-term PM10-2.5 exposure increases risks for adverse respiratory and cardiovascular outcomes, especially among certain susceptible populations. https://doi.org/10.1289/EHP658.
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Marek RF, Thorne PS, Herkert NJ, Awad AM, Hornbuckle KC. Airborne PCBs and OH-PCBs Inside and Outside Urban and Rural U.S. Schools. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2017; 51:7853-7860. [PMID: 28656752 PMCID: PMC5777175 DOI: 10.1021/acs.est.7b01910] [Citation(s) in RCA: 88] [Impact Index Per Article: 12.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/18/2023]
Abstract
PCBs appear in school air because many school buildings were built when PCBs were still intentionally added to building materials and because PCBs are also present through inadvertent production in modern pigment. This is of concern because children are especially vulnerable to the toxic effects of PCBs. Here we report indoor and outdoor air concentrations of PCBs and OH-PCBs from two rural schools and four urban schools, the latter near a PCB-contaminated waterway of Lake Michigan in the United States. Samples (n = 108) were collected as in/out pairs using polyurethane foam passive air samplers (PUF-PAS) from January 2012 to November 2015. Samples were analyzed using GC/MS-MS for all 209 PCBs and 72 OH-PCBs. Concentrations inside schools were 1-2 orders of magnitude higher than outdoors and ranged from 0.5 to 194 ng/m3 (PCBs) and from 4 to 665 pg/m3 (OH-PCBs). Congener profiles were similar within each sampling location across season but different between schools and indicated the sources as Aroclors from building materials and individual PCBs associated with modern pigment. This study is the first cohort-specific analysis to show that some children's PCB inhalation exposure may be equal to or higher than their exposure through diet.
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Gergen PJ, Mitchell HE, Calatroni A, Sever ML, Cohn RD, Salo PM, Thorne PS, Zeldin DC. Sensitization and Exposure to Pets: The Effect on Asthma Morbidity in the US Population. THE JOURNAL OF ALLERGY AND CLINICAL IMMUNOLOGY-IN PRACTICE 2017; 6:101-107.e2. [PMID: 28694047 DOI: 10.1016/j.jaip.2017.05.019] [Citation(s) in RCA: 59] [Impact Index Per Article: 8.4] [Reference Citation Analysis] [Abstract] [Key Words] [Subscribe] [Scholar Register] [Received: 10/12/2016] [Revised: 05/18/2017] [Accepted: 05/23/2017] [Indexed: 10/19/2022]
Abstract
BACKGROUND Although pets are found in more than 50% of US homes, the effect of pet allergen exposure on asthma morbidity in the US population is not well documented. OBJECTIVE To determine the effect of dog and cat allergen exposures on asthma morbidity in the US population. METHODS The National Health and Nutrition Examination Survey is a representative sample of civilian US population. Data on asthma, dog and cat allergen levels in bedroom dust, as well as specific IgE to dog and cat were analyzed for all participants 6 years or older. RESULTS Pets are common in the United States, with more that 50% of households having a dog or a cat or both. The prevalence of allergic sensitization in the National Health and Nutrition Examination Survey population was similar for dog and cat, with both being approximately 12%. Among those who were sensitized, exposure to elevated levels of pet allergens was associated with an increased prevalence of asthma and asthma attacks. Indeed, 44.2% of the asthma attacks were attributable to exposure to high levels of dog allergen in the bedroom among patients with asthma sensitive to dog and 30.3% were attributable to cat allergen exposure among the comparable cat-sensitive and exposed group. Projecting these results to the US population indicates more than 1 million increased asthma attacks each year for the dog-sensitive and exposed group and more than 500,000 increased asthma attacks for the cat-sensitive and exposed population of patients with asthma. CONCLUSIONS Exposure to elevated levels of dog and cat allergens among those sensitized individuals with asthma is associated with excess asthma attacks. Reducing pet allergen exposures has the potential for a significant decrease in asthma morbidity.
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Phipatanakul W, Koutrakis P, Coull BA, Kang CM, Wolfson JM, Ferguson ST, Petty CR, Samnaliev M, Cunningham A, Sheehan WJ, Gaffin JM, Baxi SN, Lai PS, Permaul P, Liang L, Thorne PS, Adamkiewicz G, Brennan KJ, Baccarelli AA, Gold DR. The School Inner-City Asthma Intervention Study: Design, rationale, methods, and lessons learned. Contemp Clin Trials 2017; 60:14-23. [PMID: 28619649 DOI: 10.1016/j.cct.2017.06.008] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2017] [Revised: 05/31/2017] [Accepted: 06/10/2017] [Indexed: 02/08/2023]
Abstract
Asthma is the most common chronic disease of childhood in the United States, causes significant morbidity, particularly in the inner-city, and accounts for billions of dollars in health care utilization. Home environments are established sources of exposure that exacerbate symptoms and home-based interventions are effective. However, elementary school children spend 7 to 12h a day in school, primarily in one classroom. From the observational School Inner-City Asthma Study we learned that student classroom-specific exposures are associated with worsening asthma symptoms and decline in lung function. We now embark on a randomized, blinded, sham-controlled school environmental intervention trial, built on our extensively established school/community partnerships, to determine the efficacy of a school-based intervention to improve asthma control. This factorial school/classroom based environmental intervention will plan to enroll 300 students with asthma from multiple classrooms in 40 northeastern inner-city elementary schools. Schools will be randomized to receive either integrated pest management versus control and classrooms within these schools to receive either air purifiers or sham control. The primary outcome is asthma symptoms during the school year. This study is an unprecedented opportunity to test whether a community of children can benefit from school or classroom environmental interventions. If effective, this will have great impact as an efficient, cost-effective intervention for inner city children with asthma and may have broad public policy implications.
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Sweeney S, Adamcakova-Dodd A, Thorne PS, Assouline JG. Biocompatibility of Multi-Imaging Engineered Mesoporous Silica Nanoparticles: In Vitro and Adult and Fetal In Vivo Studies. J Biomed Nanotechnol 2017; 13:544-558. [PMID: 31118876 DOI: 10.1166/jbn.2017.2369] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/10/2023]
Abstract
Despite potentially serious adverse effects of engineered nanoparticles on maternal health and fetal development, little is known about their transport across the placenta. Human and animal studies are primarily limited to ex vivo approaches; the lack of a real-time, minimally invasive tool to study transplacental transport is clear. We have developed functionalized mesoporous silica nanoparticles (MSN) for use in magnetic resonance, ultrasound, and fluorescent imaging. This material is designed as a model for, or a carrier of, environmental toxicants, allowing for in vivo evaluation. To establish a baseline of biocompatibility, we present data describing MSN tolerance using in vitro and in vivo models. In cultured cells, MSN were tolerated to a dose of 125 µg/mL with minimal effect on viability and doubling time. For the 42 day duration of the study, none of the mice exhibited behaviors usually indicative of distress (lethargy, anemia, loss of appetite, etc.). In gravid mice, the body and organ weights of MSN-exposed dams were equivalent to those of control dams. Embryos exposed to MSN during early gestation were underweight by a small degree, while embryos exposed during late gestation were of a slightly larger weight. The rate of spontaneous fetal resorptions were equivalent in exposed and control mice. Maternal livers and sera were screened for a complement of cytokines/chemokines and reactive oxygen/nitrogen species (ROS/RNS). Only granulocyte-colony stimulating factor was elevated in mice exposed to MSN during late gestation, while ROS/RNS levels were elevated in mice exposed during early/mid gestation. These findings may usher future experiments investigating environmental toxicants using real-time assessment of transport across the placenta.
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Hoppe Parr KA, Hađina S, Kilburg-Basnyat B, Wang Y, Chavez D, Thorne PS, Weiss JP. Modification of sample processing for the Limulus amebocyte lysate assay enhances detection of inflammogenic endotoxin in intact bacteria and organic dust. Innate Immun 2017; 23:307-318. [PMID: 28359219 PMCID: PMC5814115 DOI: 10.1177/1753425917694084] [Citation(s) in RCA: 15] [Impact Index Per Article: 2.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The pro-inflammatory potency and causal relationship with asthma of inhaled endotoxins have underscored the importance of accurately assessing the endotoxin content of organic dusts. The Limulus amebocyte lysate (LAL) assay has emerged as the preferred assay, but its ability to measure endotoxin in intact bacteria and organic dusts with similar sensitivity as purified endotoxin is unknown. We used metabolically radiolabeled Neisseria meningitidis and both rough and smooth Escherichia coli to compare dose-dependent activation in the LAL with purified endotoxin from these bacteria and shed outer membrane (OM) blebs. Labeled [14C]-3-OH-fatty acids were used to quantify the endotoxin content of the samples. Purified meningococcal and E. coli endotoxins and OM blebs displayed similar specific activity in the LAL assay to the purified LPS standard. In contrast, intact bacteria exhibited fivefold lower specific activity in the LAL assay but showed similar MD-2-dependent potency as purified endotoxin in inducing acute airway inflammation in mice. Pre-treatment of intact bacteria and organic dusts with 0.1 M Tris-HCl/10 mM EDTA increased by fivefold the release of endotoxin. These findings demonstrate that house dust and other organic dusts should be extracted with Tris/EDTA to more accurately assess the endotoxin content and pro-inflammatory potential of these environmental samples.
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Liu L, Urch B, Szyszkowicz M, Speck M, Leingartner K, Shutt R, Pelletier G, Gold DR, Scott JA, Brook JR, Thorne PS, Silverman FS. Influence of exposure to coarse, fine and ultrafine urban particulate matter and their biological constituents on neural biomarkers in a randomized controlled crossover study. ENVIRONMENT INTERNATIONAL 2017; 101:89-95. [PMID: 28117141 PMCID: PMC5348252 DOI: 10.1016/j.envint.2017.01.010] [Citation(s) in RCA: 18] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/18/2016] [Revised: 01/09/2017] [Accepted: 01/12/2017] [Indexed: 05/22/2023]
Abstract
BACKGROUND Epidemiological studies have reported associations between air pollution and neuro-psychological conditions. Biological mechanisms behind these findings are still not clear. OBJECTIVES We examined changes in blood and urinary neural biomarkers following exposure to concentrated ambient coarse, fine and ultrafine particles. METHODS Fifty healthy non-smoking volunteers, mean age 28years, were exposed to coarse (2.5-10μm, mean 213μg/m3) and fine (0.15-2.5μm, mean 238μg/m3) concentrated ambient particles (CAPs), and filtered ambient and/or medical air. Twenty-five participants were exposed to ultrafine CAP (mean size 59.6nm, range 47.0-69.8nm), mean (136μg/m3) and filtered medical air. Exposures lasted 130min, separated by ≥2weeks, and the biological constituents endotoxin and β-1,3-d-glucan of each particle size fraction were measured. Blood and urine samples were collected pre-exposure, and 1-hour and 21-hour post-exposure to determine neural biomarker levels. Mixed-model regressions assessed associations between exposures and changes in biomarker levels. RESULTS Results were expressed as percent change from daily pre-exposure biomarker levels. Exposure to coarse CAP was significantly associated with increased urinary levels of the stress-related biomarkers vanillylmandelic acid (VMA) and cortisol when compared with exposure to filtered medical air [20% (95% confidence interval: 1.0%, 38%) and 64% (0.2%, 127%), respectively] 21hours post-exposure. However exposure to coarse CAP was significantly associated with decreases in blood cortisol [-26.0% (-42.4%, -9.6%) and -22.4% (-43.7%, -1.1%) at 1h and 21h post-exposure, respectively]. Biological molecules present in coarse CAP were significantly associated with blood biomarkers indicative of blood brain barrier integrity. Endotoxin content was significantly associated with increased blood ubiquitin C-terminal hydrolase L1 [UCHL1, 11% (5.3%, 16%) per ln(ng/m3+1)] 1-hour post-exposure, while β-1,3-d-glucan was significantly associated with increased blood S100B [6.3% (3.2%, 9.4%) per ln(ng/m3+1)], as well as UCHL1 [3.1% (0.4%, 5.9%) per ln(ng/m3+1)], one-hour post-exposure. Fine CAP was marginally associated with increased blood UCHL1 when compared with exposure to filtered medical air [17.7% (-1.7%, 37.2%), p=0.07] 21hours post-exposure. Ultrafine CAP was not significantly associated with changes in any blood and urinary neural biomarkers examined. CONCLUSION Ambient coarse particulate matter and its biological constituents may influence neural biomarker levels that reflect perturbations of blood-brain barrier integrity and systemic stress response.
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Grimm FA, Lehmler HJ, Koh WX, DeWall J, Teesch LM, Hornbuckle KC, Thorne PS, Robertson LW, Duffel MW. Identification of a sulfate metabolite of PCB 11 in human serum. ENVIRONMENT INTERNATIONAL 2017; 98:120-128. [PMID: 27816204 PMCID: PMC5127762 DOI: 10.1016/j.envint.2016.10.023] [Citation(s) in RCA: 33] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 10/21/2016] [Accepted: 10/25/2016] [Indexed: 05/18/2023]
Abstract
Despite increasing evidence for a major role for sulfation in the metabolism of lower-chlorinated polychlorinated biphenyls in vitro and in vivo, and initial evidence for potential bioactivities of the resulting sulfate ester metabolites, the formation of PCB sulfates in PCB exposed human populations had not been explored. The primary goal of this study was to determine if PCB sulfates, and potentially other conjugated PCB derivatives, are relevant classes of PCB metabolites in the serum of humans with known exposures to PCBs. In order to detect and quantify dichlorinated PCB sulfates in serum samples of 46 PCB-exposed individuals from either rural or urban communities, we developed a high-resolution mass spectrometry-based protocol using 4-PCB 11 sulfate as a model compound. The method also allowed the preliminary analysis of these 46 human serum extracts for the presence of other metabolites, such as glucuronic acid conjugates and hydroxylated PCBs. Sulfate ester metabolites derived from dichlorinated PCBs were detectable and quantifiable in more than 20% of analyzed serum samples. Moreover, we were able to utilize this method to detect PCB glucuronides and hydroxylated PCBs, albeit at lower frequencies than PCB sulfates. Altogether, our results provide initial evidence for the presence of PCB sulfates in human serum. Considering the inability of previously employed analytical protocols for PCBs to extract these sulfate ester metabolites and the concentrations of these metabolites observed in our current study, our data support the hypothesis that total serum levels of PCB metabolites in exposed individuals may have been underestimated in the past.
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