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Mitroo D, Das DN, Hamilton PD, Kumfer BM, Ravi N. Combustion conditions influence toxicity of flame-generated soot to ocular (ARPE-19) cells. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2024; 344:123307. [PMID: 38190877 DOI: 10.1016/j.envpol.2024.123307] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/09/2023] [Revised: 12/18/2023] [Accepted: 01/04/2024] [Indexed: 01/10/2024]
Abstract
Soot is a prevalent aerosol found both indoors and outdoors that has several sources, such as natural (e.g., wildfires), civilian (e.g., cooking), or military (e.g., burn pit operation). Additionally, within the sources, factors that influence the physicochemical properties of the soot include combustion temperature, oxygen availability, and fuel type. Being able to reproduce soot in the laboratory and systematically assess its toxicity is important in the pursuit of elucidating pathologies associated with its exposure. Of the organs of interest, we targeted the eye given the scant attention received. Yet, air pollution constituents such as soot have been linked to diseases such as age-related macular degeneration and proliferative vitreoretinopathy. We developed a bench-scale system to synthesize different types of soot, that is, soot with a systematically varied physical attributes or chemical composition. We used common analytical techniques to probe such properties, and used statistical analyses to correlate them with toxicity in vitro using ARPE-19 cells. Within the range of flame conditions studied, we find that soot toxicity increases with increasing oxygen concentration in fuel-rich premixed flames, and weakly increases with decreasing flame temperature. Additionally, soot particles produced in premixed flames are generally smaller in size, exhibit a lesser fractal structure, and are considerably more toxic to ARPE-19 cells than soot particles produced in non-premixed flames.
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Affiliation(s)
- Dhruv Mitroo
- Veterans Research and Education Foundation, St. Louis, MO, 63103, USA; Veterans Affairs Medical Center, St. Louis, MO, 63103, USA
| | - Durgesh N Das
- Department of Ophthalmology and Visual Sciences, Washington University in St. Louis, St. Louis MO 63110, USA
| | - Paul D Hamilton
- Veterans Research and Education Foundation, St. Louis, MO, 63103, USA; Veterans Affairs Medical Center, St. Louis, MO, 63103, USA
| | - Benjamin M Kumfer
- Center for Aerosol Science and Engineering, Department of Energy, Environmental, and Chemical Engineering, Washington University, St. Louis, MO 63130, USA
| | - Nathan Ravi
- Veterans Research and Education Foundation, St. Louis, MO, 63103, USA; Veterans Affairs Medical Center, St. Louis, MO, 63103, USA; Department of Ophthalmology and Visual Sciences, Washington University in St. Louis, St. Louis MO 63110, USA; Center for Aerosol Science and Engineering, Department of Energy, Environmental, and Chemical Engineering, Washington University, St. Louis, MO 63130, USA.
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Bein KJ, Wallis CD, Silverman JL, Lein PJ, Wexler AS. Emulating Near-Roadway Exposure to Traffic-Related Air Pollution via Real-Time Emissions from a Major Freeway Tunnel System. ENVIRONMENTAL SCIENCE & TECHNOLOGY 2022; 56:10.1021/acs.est.1c07047. [PMID: 35235290 PMCID: PMC9437142 DOI: 10.1021/acs.est.1c07047] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/11/2023]
Abstract
Epidemiological and toxicological studies continue to demonstrate correlative and causal relationships between exposure to traffic-related air pollution and various metrics of adverse pulmonary, cardiovascular, and neurological health effects. The key challenge for in vivo studies is replicating real-world, near-roadway exposure dynamics in laboratory animal models that mimic true human exposures. The advantage of animal models is the accelerated time scales to show statistically significant physiological and/or behavioral response. This work describes a novel exposure facility adjacent to a major freeway tunnel system that provides a platform for real-time chronic exposure studies. The primary conclusion is that particulate matter (PM) concentrations at this facility are routinely well below the National Ambient Air Quality Standards (NAAQS), but studies completed to date still demonstrate significant neurological and cardiovascular effects. Internal combustion engines produce large numbers of ultrafine particles that contribute negligible mass to the atmosphere relative to NAAQS regulated PM2.5 but have high surface area and mobility in the body. It is posited here that current federal and state air quality standards are thus insufficient to fully protect human health, most notably the developing and aging brain, due to regulatory gaps for ultrafine particles.
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Affiliation(s)
- Keith J Bein
- Air Quality Research Center, University of California, Davis, California 95616, United States
- Center for Health & the Environment, University of California, Davis, California 95616, United States
| | - Chris D Wallis
- Air Quality Research Center, University of California, Davis, California 95616, United States
| | - Jill L Silverman
- Dept. of Psychiatry and Behavioral Sciences, University of California, Davis, California 95616, United States
- The MIND Institute, University of California, Davis, California 95616, United States
| | - Pamela J Lein
- The MIND Institute, University of California, Davis, California 95616, United States
- Department of Molecular Biosciences, University of California, Davis, California 95616, United States
| | - Anthony S Wexler
- Air Quality Research Center, University of California, Davis, California 95616, United States
- Department of Mechanical and Aerospace Engineering, University of California, Davis, California 95616, United States
- Department of Civil and Environmental Engineering, University of California, Davis, California 95616, United States
- Department of Land, Air and Water Resources, University of California, Davis, California 95616, United States
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Outdoor Air Pollution and New-Onset Airway Disease. An Official American Thoracic Society Workshop Report. Ann Am Thorac Soc 2021; 17:387-398. [PMID: 32233861 PMCID: PMC7175976 DOI: 10.1513/annalsats.202001-046st] [Citation(s) in RCA: 97] [Impact Index Per Article: 32.3] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/17/2022] Open
Abstract
Although it is well accepted that air pollution exposure exacerbates preexisting airway disease, it has not been firmly established that long-term pollution exposure increases the risk of new-onset asthma or chronic obstruction pulmonary disease (COPD). This Workshop brought together experts on mechanistic, epidemiological, and clinical aspects of airway disease to review current knowledge regarding whether air pollution is a causal factor in the development of asthma and/or COPD. Speakers presented recent evidence in their respective areas of expertise related to air pollution and new airway disease incidence, followed by interactive discussions. A writing committee summarized their collective findings. The Epidemiology Group found that long-term exposure to air pollution, especially metrics of traffic-related air pollution such as nitrogen dioxide and black carbon, is associated with onset of childhood asthma. However, the evidence for a causal role in adult-onset asthma or COPD remains insufficient. The Mechanistic Group concluded that air pollution exposure can cause airway remodeling, which can lead to asthma or COPD, as well as asthma-like phenotypes that worsen with long-term exposure to air pollution, especially fine particulate matter and ozone. The Clinical Group concluded that air pollution is a plausible contributor to the onset of both asthma and COPD. Available evidence indicates that long-term exposure to air pollution is a cause of childhood asthma, but the evidence for a similar determination for adult asthma or COPD remains insufficient. Further research is needed to elucidate the exact biological mechanism underlying incident childhood asthma, and the specific air pollutant that causes it.
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Henry FS, Tsuda A. Onset of alveolar recirculation in the developing lungs and its consequence on nanoparticle deposition in the pulmonary acinus. J Appl Physiol (1985) 2016; 120:38-54. [PMID: 26494453 PMCID: PMC4698443 DOI: 10.1152/japplphysiol.01161.2014] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/30/2014] [Accepted: 10/08/2015] [Indexed: 01/17/2023] Open
Abstract
The structure of the gas exchange region of the human lung (the pulmonary acinus) undergoes profound change in the first few years of life. In this paper, we investigate numerically how the change in alveolar shape with time affects the rate of nanoparticle deposition deep in the lung during postnatal development. As human infant data is unavailable, we use a rat model of lung development. The process of postnatal lung development in the rat is remarkably similar to that of the human, and the structure of the rat acinus is indistinguishable from that of the human acinus. The current numerical predictions support our group's recent in vivo findings, which were also obtained by using growing rat lung models, that nanoparticle deposition in infants is strongly affected by the change in the structure of the pulmonary acinus. In humans, this major structural change occurs over the first 2 yr of life. Our current predictions would suggest that human infants at the age of ∼ 2 yr might be most at risk to the harmful effects of air pollution. Our results also suggest that dose estimates for inhalation therapies using nanoparticles, based on fully developed adult lungs with simple body weight scaling, are likely to overestimate deposition by up to 55% for newborns and underestimate deposition by up to 17% for 2-yr-old infants.
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Affiliation(s)
- Frank S Henry
- Molecular and Integrative Physiological Sciences, Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts; and Deptartment of Mechanical Engineering, Manhattan College, Riverdale, New York
| | - Akira Tsuda
- Molecular and Integrative Physiological Sciences, Department of Environmental Health, Harvard School of Public Health, Boston, Massachusetts; and
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Cichocki JA, Smith GJ, Mendoza R, Buckpitt AR, Van Winkle LS, Morris JB. Sex differences in the acute nasal antioxidant/antielectrophilic response of the rat to inhaled naphthalene. Toxicol Sci 2014; 139:234-44. [PMID: 24563378 DOI: 10.1093/toxsci/kfu031] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/30/2022] Open
Abstract
Naphthalene is a nasal carcinogen, inducing respiratory adenomas in male and olfactory neuroblastomas in female rats, respectively. The reasons for the site and sex-specific tumorigenic response are unknown. Naphthalene is bioactivated to electrophilic metabolites; cytotoxicity followed by regenerative cell proliferation is likely involved in the tumorigenic response. To examine sex differences in the acute nasal response to naphthalene, male and female F344 rats were nose-only exposed to 0, 1, 3, 10, or 30 ppm naphthalene vapor for 4 or 6 h. Following exposure, respiratory/transitional mucosa (RTM) and olfactory mucosa (OM) were isolated and analyzed for markers of oxidant/electrophilic stress and/or toxicity, including reduced/oxidized glutathione levels (GSH/GSSG), mRNA levels of electrophile-responsive genes, and epithelial cytoxicity (as measured by membrane permeability to ethidium homodimer-1). Naphthalene caused significant depletion of GSH in RTM and OM with no increase in GSSG. Cytotoxicity was apparent at concentrations of 15 and 30 ppm. No consistent sex differences were observed in these responses. Sex differences were observed in the induction of antielectrophilic genes in OM: glutamyl cysteine ligase (catalytic subunit) (Gclc), NADPH quinone oxidase 1 (Nqo1), and heme oxygenase 1 (Hmox1) were all induced to a greater extent in the male OM compared with the female. No consistent sex differences were observed in the RTM. Although the mechanism of the sex difference in the RTM adenoma response remains enigmatic, sex differences in the induction of antioxidant/electrophile-responsive genes may contribute to the heightened sensitivity of the female OM to the carcinogenic effects of naphthalene.
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Affiliation(s)
- Joseph A Cichocki
- University of Connecticut, Department of Pharmaceutical Sciences, Toxicology Program, Storrs, Connecticut, 06269
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Long CM, Nascarella MA, Valberg PA. Carbon black vs. black carbon and other airborne materials containing elemental carbon: physical and chemical distinctions. ENVIRONMENTAL POLLUTION (BARKING, ESSEX : 1987) 2013; 181:271-86. [PMID: 23850403 DOI: 10.1016/j.envpol.2013.06.009] [Citation(s) in RCA: 174] [Impact Index Per Article: 15.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/15/2013] [Revised: 06/10/2013] [Accepted: 06/16/2013] [Indexed: 05/19/2023]
Abstract
Airborne particles containing elemental carbon (EC) are currently at the forefront of scientific and regulatory scrutiny, including black carbon, carbon black, and engineered carbon-based nanomaterials, e.g., carbon nanotubes, fullerenes, and graphene. Scientists and regulators sometimes group these EC-containing particles together, for example, interchangeably using the terms carbon black and black carbon despite one being a manufactured product with well-controlled properties and the other being an undesired, incomplete-combustion byproduct with diverse properties. In this critical review, we synthesize information on the contrasting properties of EC-containing particles in order to highlight significant differences that can affect hazard potential. We demonstrate why carbon black should not be considered a model particle representative of either combustion soots or engineered carbon-based nanomaterials. Overall, scientific studies need to distinguish these highly different EC-containing particles with care and precision so as to forestall unwarranted extrapolation of properties, hazard potential, and study conclusions from one material to another.
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Chan JKW, Charrier JG, Kodani SD, Vogel CF, Kado SY, Anderson DS, Anastasio C, Van Winkle LS. Combustion-derived flame generated ultrafine soot generates reactive oxygen species and activates Nrf2 antioxidants differently in neonatal and adult rat lungs. Part Fibre Toxicol 2013; 10:34. [PMID: 23902943 PMCID: PMC3735485 DOI: 10.1186/1743-8977-10-34] [Citation(s) in RCA: 49] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/02/2012] [Accepted: 07/10/2013] [Indexed: 01/10/2023] Open
Abstract
BACKGROUND Urban particulate matter (PM) has been epidemiologically correlated with multiple cardiopulmonary morbidities and mortalities, in sensitive populations. Children exposed to PM are more likely to develop respiratory infections and asthma. Although PM originates from natural and anthropogenic sources, vehicle exhaust rich in polycyclic aromatic hydrocarbons (PAH) can be a dominant contributor to the PM2.5 and PM0.1 fractions and has been implicated in the generation of reactive oxygen species (ROS). OBJECTIVES Current studies of ambient PM are confounded by the variable nature of PM, so we utilized a previously characterized ethylene-combusted premixed flame particles (PFP) with consistent and reproducible physiochemical properties and 1) measured the oxidative potential of PFP compared to ambient PM, 2) determined the ability of PFPs to generate oxidative stress and activate the transcription factor using in vitro and ex vivo models, and 3) we correlated these responses with antioxidant enzyme expression in vivo. METHODS We compared oxidative stress response (HMOX1) and antioxidant enzyme (SOD1, SOD2, CAT, and PRDX6) expression in vivo by performing a time-course study in 7-day old neonatal and young adult rats exposed to a single 6-hour exposure to 22.4 μg/m3 PFPs. RESULTS We showed that PFP is a potent ROS generator that induces oxidative stress and activates Nrf2. Induction of the oxidative stress responsive enzyme HMOX1 in vitro was mediated through Nrf2 activation and was variably upregulated in both ages. Furthermore, antioxidant enzyme expression had age and lung compartment variations post exposure. Of particular interest was SOD1, which had mRNA and protein upregulation in adult parenchyma, but lacked a similar response in neonates. CONCLUSIONS We conclude that PFPs are effective ROS generators, comparable to urban ambient PM2.5, that induce oxidative stress in neonatal and adult rat lungs. PFPs upregulate a select set of antioxidant enzymes in young adult animals, that are unaffected in neonates. We conclude that the inability of neonatal animals to upregulate the antioxidant response may, in part, explain enhanced their susceptibility to ultrafine particles, such as PFP.
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Affiliation(s)
- Jackie K W Chan
- Center for Health and the Environment, University of California, One Shields Ave, Davis, CA 95616, USA
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Chan JKW, Vogel CF, Baek J, Kodani SD, Uppal RS, Bein KJ, Anderson DS, Van Winkle LS. Combustion derived ultrafine particles induce cytochrome P-450 expression in specific lung compartments in the developing neonatal and adult rat. Am J Physiol Lung Cell Mol Physiol 2013; 304:L665-77. [PMID: 23502512 DOI: 10.1152/ajplung.00370.2012] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/06/2023] Open
Abstract
Vehicle exhaust is rich in polycyclic aromatic hydrocarbons (PAH) and can be a dominant contributor to ultrafine urban particulate matter (PM). Exposure to ultrafine PM is correlated with respiratory infections and asthmatic symptoms in young children. The lung undergoes substantial growth, alveolarization, and cellular maturation within the first years of life, which may be impacted by environmental pollutants such as PM. PAHs in PM can serve as ligands for the aryl hydrocarbon receptor (AhR) that induces expression of certain isozymes in the cytochrome P-450 superfamily, such as CYP1A1 and CYP1B1, localized in specific lung cell types. Although AhR activation and induction has been widely studied, its context within PM exposure and impact on the developing lung is poorly understood. In response, we have developed a replicable ultrafine premixed flame particle (PFP) generating system and used in vitro and in vivo models to define PM effects on AhR activation in the developing lung. We exposed 7-day neonatal and adult rats to a single 6-h PFP exposure and determined that PFPs cause significant parenchymal toxicity in neonates. PFPs contain weak AhR agonists that upregulate AhR-xenobiotic response element activity and expression and are capable inducers of CYP1A1 and CYP1B1 expression in both ages with different spatial and temporal patterns. Neonatal CYP1A1 expression was muted and delayed compared with adults, possibly because of differences in the enzyme maturation. We conclude that the inability of neonates to sufficiently adapt in response to PFP exposure may, in part, explain their susceptibility to PFP and urban ultrafine PM.
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Affiliation(s)
- Jackie K W Chan
- Center for Health and the Environment, University of California, Davis, Davis, CA 95616, USA
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Chan JKW, Kodani SD, Charrier JG, Morin D, Edwards PC, Anderson DS, Anastasio C, Van Winkle LS. Age-specific effects on rat lung glutathione and antioxidant enzymes after inhaling ultrafine soot. Am J Respir Cell Mol Biol 2012; 48:114-24. [PMID: 23065132 DOI: 10.1165/rcmb.2012-0108oc] [Citation(s) in RCA: 15] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Vehicle exhaust is rich in polycyclic aromatic hydrocarbons (PAHs) and is a dominant contributor to urban particulate pollution (PM). Exposure to PM is linked to respiratory and cardiovascular morbidity and mortality in susceptible populations, such as children. PM can contribute to the development and exacerbation of asthma, and this is thought to occur because of the presence of electrophiles in PM or through electrophile generation via the metabolism of PAHs. Glutathione (GSH), an abundant intracellular antioxidant, confers cytoprotection through conjugation of electrophiles and reduction of reactive oxygen species. GSH-dependent phase II detoxifying enzymes glutathione peroxidase and glutathione S-transferase facilitate metabolism and conjugation, respectively. Ambient particulates are highly variable in composition, which complicates systematic study. In response, we have developed a replicable ultrafine premixed flame particle (PFP)-generating system for in vivo studies. To determine particle effects in the developing lung, 7-day-old neonatal and adult rats inhaled 22 μg/m(3) PFP during a single 6-hour exposure. Pulmonary GSH and related phase II detoxifying gene and protein expression were evaluated 2, 24, and 48 hours after exposure. Neonates exhibited significant depletion of GSH despite higher initial baseline levels of GSH. Furthermore, we observed attenuated induction of phase II enzymes (glutamate cysteine ligase, glutathione reductase, glutathione S-transferase, and glutathione peroxidase) in neonates compared with adult rats. We conclude that developing neonates have a limited ability to deviate from their normal developmental pattern that precludes adequate adaptation to environmental pollutants, which results in enhanced cytotoxicity from inhaled PM.
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Affiliation(s)
- Jackie K W Chan
- Center for Health and the Environment, University of California at Davis, Davis, California 95616-8732, USA
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Current world literature. Curr Opin Pediatr 2012; 24:277-84. [PMID: 22414891 DOI: 10.1097/mop.0b013e328351e459] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/27/2022]
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Yatera K, Morimoto Y, Kim HN, Myojo T, Mukae H. Foam cell formation of alveolar macrophages in Clara cell ablated mice inhaling crystalline silica. Inhal Toxicol 2012; 23:736-44. [PMID: 21967498 DOI: 10.3109/08958378.2011.608741] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
We investigated the function of Clara cells in vivo during exposure to inhaled crystalline silica by morphological and immunohistochemical examination of intra-alveolar cells and alveolar macrophages in Clara cell-ablated mice. The Clara cells of male FVB/n mice (8-12 weeks old) were ablated by intraperitoneal administration of naphthalene (300 mg/kg). The mice were then exposed to crystalline silica (Min-U-Sil-5, 97.1 ± 9.5 mg/m³, 6 hours/day, 5 days/week) for up to two weeks. The lungs were assessed by morphometry, as well as by immunohistochemistry of CD36, lectin-like oxygenated low-density lipoprotein receptor (LOX)-1, and matrix metalloproteinases (MMPs) -2, -9 and -12. There was a significantly greater number of intra-alveolar cells in Clara cell-ablated mouse groups than in wild-type mouse groups that were exposed to crystalline silica. A marked number of foamy alveolar macrophages were only detected in the Clara cell-ablated group exposed to crystalline silica, indicating that Clara cells inhibit infiltration and foam cell formation of alveolar macrophages. Immunohistochemical analysis indicated that foamy alveolar macrophages in the Clara cell-ablated group that inhaled crystalline silica overexpress CD36 and LOX-1, indicating upregulation of scavenger receptors of alveolar macrophages. These cells also express MMP-2, -9 and -12, suggesting increased gelatinolytic and elastolytic activities. Our findings suggest that Clara cells not only inhibit infiltration of alveolar macrophages but also their phagocytotic and gelatinolytic functions in silica-induced pulmonary injury.
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Affiliation(s)
- Kazuhiro Yatera
- Department of Respiratory Medicine, University of Occupational and Environmental Health, Japan.
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Chan JKW, Fanucchi MV, Anderson DS, Abid AD, Wallis CD, Dickinson DA, Kumfer BM, Kennedy IM, Wexler AS, Van Winkle LS. Susceptibility to inhaled flame-generated ultrafine soot in neonatal and adult rat lungs. Toxicol Sci 2011; 124:472-86. [PMID: 21914721 DOI: 10.1093/toxsci/kfr233] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/25/2022] Open
Abstract
Over a quarter of the U.S. population is exposed to harmful levels of airborne particulate matter (PM) pollution, which has been linked to development and exacerbation of respiratory diseases leading to morbidity and mortality, especially in susceptible populations. Young children are especially susceptible to PM and can experience altered anatomic, physiologic, and biological responses. Current studies of ambient PM are confounded by the complex mixture of soot, metals, allergens, and organics present in the complex mixture as well as seasonal and temporal variance. We have developed a laboratory-based PM devoid of metals and allergens that can be replicated to study health effects of specific PM components in animal models. We exposed 7-day-old postnatal and adult rats to a single 6-h exposure of fuel-rich ultrafine premixed flame particles (PFPs) or filtered air. These particles are high in polycyclic aromatic hydrocarbons content. Pulmonary cytotoxicity, gene, and protein expression were evaluated at 2 and 24 h postexposure. Neonates were more susceptible to PFP, exhibiting increased lactate dehydrogenase activity in bronchoalveolar lavage fluid and ethidium homodimer-1 cellular staining in the lung in situ as an index of cytotoxicity. Basal gene expression between neonates and adults differed for a significant number of antioxidant, oxidative stress, and proliferation genes and was further altered by PFP exposure. PFP diminishes proliferation marker PCNA gene and protein expression in neonates but not adults. We conclude that neonates have an impaired ability to respond to environmental exposures that increases lung cytotoxicity and results in enhanced susceptibility to PFP, which may lead to abnormal airway growth.
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Affiliation(s)
- Jackie K W Chan
- Center for Health and the Environment, University of California, Davis, Davis, California 95616, USA
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