1
|
Stevens NC, Shen T, Martinez J, Evans VJB, Domanico MC, Neumann EK, Van Winkle LS, Fiehn O. Resolving multi-image spatial lipidomic responses to inhaled toxicants by machine learning. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2024:2024.07.05.602264. [PMID: 39026864 PMCID: PMC11257454 DOI: 10.1101/2024.07.05.602264] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/20/2024]
Abstract
Regional responses to inhaled toxicants are essential to understand the pathogenesis of lung disease under exposure to air pollution. We evaluated the effect of combined allergen sensitization and ozone exposure on eliciting spatial differences in lipid distribution in the mouse lung that may contribute to ozone-induced exacerbations in asthma. Lung lobes from male and female BALB/c mice were cryosectioned and acquired by high resolution mass spectrometry imaging (MSI). Processed MSI peak annotations were validated by LC-MS/MS data from scraped tissue slides and microdissected lung tissue. Images were normalized and segmented into clusters. Interestingly, segmented clusters overlapped with stained serial tissue sections, enabling statistical analysis across biological replicates for morphologically relevant lung regions. Spatially distinct lipids had higher overall degree of unsaturated fatty acids in distal lung regions compared to proximal regions. Furthermore, the airway and alveolar epithelium exhibited significantly decreased sphingolipid and glycerophospholipid abundance in females, but not in males. We demonstrate the potential role of lipid saturation in healthy lung function and highlight sex differences in regional lung lipid distribution following ozone exposure. Our study provides a framework for future MSI experiments capable of relative quantification across biological replicates and expansion to multiple sample types, including human tissue.
Collapse
|
2
|
Kelty J, Kovalchuk N, Uwimana E, Yin L, Ding X, Van Winkle L. In vitro airway models from mice, rhesus macaques, and humans maintain species differences in xenobiotic metabolism and cellular responses to naphthalene. Am J Physiol Lung Cell Mol Physiol 2022; 323:L308-L328. [PMID: 35853015 PMCID: PMC9423729 DOI: 10.1152/ajplung.00349.2021] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 04/04/2022] [Accepted: 07/01/2022] [Indexed: 11/22/2022] Open
Abstract
The translational value of high-throughput toxicity testing will depend on pharmacokinetic validation. Yet, popular in vitro airway epithelia models were optimized for structure and mucociliary function without considering the bioactivation or detoxification capabilities of lung-specific enzymes. This study evaluated xenobiotic metabolism maintenance within differentiated air-liquid interface (ALI) airway epithelial cell cultures (human bronchial; human, rhesus, and mouse tracheal), isolated airway epithelial cells (human, rhesus, and mouse tracheal; rhesus bronchial), and ex vivo microdissected airways (rhesus and mouse) by measuring gene expression, glutathione content, and naphthalene metabolism. Glutathione levels and detoxification gene transcripts were measured after 1-h exposure to 80 µM naphthalene (a bioactivated toxicant) or reactive naphthoquinone metabolites. Glutathione and glutathione-related enzyme transcript levels were maintained in ALI cultures from all species relative to source tissues, while cytochrome P450 monooxygenase gene expression declined. Notable species differences among the models included a 40-fold lower total glutathione content for mouse ALI trachea cells relative to human and rhesus; a higher rate of naphthalene metabolism in mouse ALI cultures for naphthalene-glutathione formation (100-fold over rhesus) and naphthalene-dihydrodiol production (10-fold over human); and opposite effects of 1,2-naphthoquinone exposure in some models-glutathione was depleted in rhesus tissue but rose in mouse ALI samples. The responses of an immortalized bronchial cell line to naphthalene and naphthoquinones were inconsistent with those of human ALI cultures. These findings of preserved species differences and the altered balance of phase I and phase II xenobiotic metabolism among the characterized in vitro models should be considered for future pulmonary toxicity testing.
Collapse
Affiliation(s)
- Jacklyn Kelty
- Department of Anatomy, Physiology and Cell Biology, Center for Comparative Respiratory Biology and Medicine, School of Veterinary Medicine and Center for Health and the Environment, University of California at Davis, Davis, California
| | - Nataliia Kovalchuk
- Pharmacology and Toxicology Department, College of Pharmacy, University of Arizona, Tucson, Arizona
| | - Eric Uwimana
- Pharmacology and Toxicology Department, College of Pharmacy, University of Arizona, Tucson, Arizona
| | - Lei Yin
- Pharmacology and Toxicology Department, College of Pharmacy, University of Arizona, Tucson, Arizona
| | - Xinxin Ding
- Pharmacology and Toxicology Department, College of Pharmacy, University of Arizona, Tucson, Arizona
| | - Laura Van Winkle
- Department of Anatomy, Physiology and Cell Biology, Center for Comparative Respiratory Biology and Medicine, School of Veterinary Medicine and Center for Health and the Environment, University of California at Davis, Davis, California
| |
Collapse
|
3
|
Flayer CH, Larson ED, Joseph A, Kao S, Qu W, Van Haren A, Royer CM, Miller LA, Capitanio JP, Sielecki T, Christofidou-Solomidou M, Haczku A. Ozone-induced enhancement of airway hyperreactivity in rhesus macaques: Effects of antioxidant treatment. J Allergy Clin Immunol 2020; 145:312-323. [PMID: 31627909 PMCID: PMC6949398 DOI: 10.1016/j.jaci.2019.08.034] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/23/2019] [Revised: 07/18/2019] [Accepted: 08/30/2019] [Indexed: 12/18/2022]
Abstract
BACKGROUND Ozone (O3) inhalation elicits airway inflammation and impairs treatment responsiveness in asthmatic patients. The underlying immune mechanisms have been difficult to study because of the lack of relevant experimental models. Rhesus macaques spontaneously have asthma and have a similar immune system to human subjects. OBJECTIVES We sought to investigate mucosal immune changes after O3 inhalation in a clinically relevant nonhuman primate asthma model and to study the effects of an antioxidant synthetic lignan (synthetic secoisolariciresinol diglucoside [LGM2605]). METHODS A cohort of macaques (n = 17) previously characterized with airway hyperreactivity (AHR) to methacholine was assessed (day 1). Macaques were treated (orally) with LGM2605 (25 mg/kg) or placebo twice per day for 7 days, exposed to 0.3 ppm O3 or air for 6 hours (on day 7), and studied 12 hours later (day 8). Lung function, blood and bronchoalveolar lavage (BAL) fluid immune cell profile, and bronchial brushing and blood cell mRNA expression were assessed. RESULTS O3 induced significant BAL fluid neutrophilia and eosinophilia and increased AHR and expression of IL6 and IL25 mRNA in the airway epithelium together with increased BAL fluid group 2 innate lymphoid cell (ILC2s), CD1c+ myeloid dendritic cell, and CD4+ T-cell counts and diminished surfactant protein D expression. Although LGM2605 attenuated some of the immune and inflammatory changes, it completely abolished O3-induced AHR. CONCLUSION ILC2s, CD1c+ myeloid dendritic cells, and CD4+ T cells are selectively involved in O3-induced asthma exacerbation. The inflammatory changes were partially prevented by antioxidant pretreatment with LGM2605, which had an unexpectedly disproportionate protective effect on AHR.
Collapse
Affiliation(s)
- Cameron H Flayer
- Pulmonary, Critical Care and Sleep Division, Department of Medicine, UC Davis School of Medicine, Davis, Calif
| | - Erik D Larson
- Pulmonary, Critical Care and Sleep Division, Department of Medicine, UC Davis School of Medicine, Davis, Calif
| | - Anjali Joseph
- Pulmonary, Critical Care and Sleep Division, Department of Medicine, UC Davis School of Medicine, Davis, Calif
| | - Sean Kao
- Pulmonary, Critical Care and Sleep Division, Department of Medicine, UC Davis School of Medicine, Davis, Calif
| | - Wenxiu Qu
- Pulmonary, Critical Care and Sleep Division, Department of Medicine, UC Davis School of Medicine, Davis, Calif; Department of Pediatrics, Shengjing Hospital, China Medical University, Shenyang, China
| | - Austin Van Haren
- Pulmonary, Critical Care and Sleep Division, Department of Medicine, UC Davis School of Medicine, Davis, Calif
| | | | - Lisa A Miller
- UC Davis California National Primate Research Center, Davis, Calif
| | - John P Capitanio
- UC Davis California National Primate Research Center, Davis, Calif
| | | | - Melpo Christofidou-Solomidou
- Pulmonary, Allergy and Critical Care Division, Department of Medicine, University of Pennsylvania, Philadelphia, Pa
| | - Angela Haczku
- Pulmonary, Critical Care and Sleep Division, Department of Medicine, UC Davis School of Medicine, Davis, Calif.
| |
Collapse
|
4
|
Van Winkle LS, Kelty JS, Plopper CG. Preparation of Specific Compartments of the Lungs for Pathologic and Biochemical Analysis of Toxicologic Responses. ACTA ACUST UNITED AC 2017; 71:24.5.1-24.5.26. [PMID: 28146282 DOI: 10.1002/cptx.18] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/26/2022]
Abstract
This unit focuses on protocols for assessing microenvironment-specific responses in the thoracic lung tissues. Aspects of the entire respiratory system serve as potential targets for candidate toxicants, but each candidate toxicant may impact distinct sites due to differential distribution of either the toxicant or the target cells. Within the conducting airways, the composition of resident cell populations and the metabolic capabilities of the cell populations vary greatly. Thus, studies of this region of the lung require unique, site-selective methods to clearly define the toxic response. Without site-specific sampling, as described in this chapter, the experimental limit of detection for toxicant effects in conducting airways is weakened because differences unrelated to treatment, but related to location, may dominate the response. The protocols included here allow assessment of toxicological responses in the tracheobronchial airways and the gas exchange area of the lung, with specific application to laboratory mammals. © 2017 by John Wiley & Sons, Inc.
Collapse
Affiliation(s)
- Laura S Van Winkle
- Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California, Davis, California.,John Muir Institute for the Environment, Center for Health and the Environment, University of California, Davis, California
| | - Jacklyn S Kelty
- Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California, Davis, California.,John Muir Institute for the Environment, Center for Health and the Environment, University of California, Davis, California
| | - Charles G Plopper
- Department of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California, Davis, California
| |
Collapse
|
5
|
Albertine KH. Utility of large-animal models of BPD: chronically ventilated preterm lambs. Am J Physiol Lung Cell Mol Physiol 2015; 308:L983-L1001. [PMID: 25770179 PMCID: PMC4437012 DOI: 10.1152/ajplung.00178.2014] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2014] [Accepted: 02/19/2015] [Indexed: 11/22/2022] Open
Abstract
This paper is focused on unique insights provided by the preterm lamb physiological model of bronchopulmonary dysplasia (BPD). Connections are also made to insights provided by the former preterm baboon model of BPD, as well as to rodent models of lung injury to the immature, postnatal lung. The preterm lamb and baboon models recapitulate the clinical setting of preterm birth and respiratory failure that require prolonged ventilation support for days or weeks with oxygen-rich gas. An advantage of the preterm lamb model is the large size of preterm lambs, which facilitates physiological studies for days or weeks during the evolution of neonatal chronic lung disease (CLD). To this advantage is linked an integrated array of morphological, biochemical, and molecular analyses that are identifying the role of individual genes in the pathogenesis of neonatal CLD. Results indicate that the mode of ventilation, invasive mechanical ventilation vs. less invasive high-frequency nasal ventilation, is related to outcomes. Our approach also includes pharmacological interventions that test causality of specific molecular players, such as vitamin A supplementation in the pathogenesis of neonatal CLD. The new insights that are being gained from our preterm lamb model may have important translational implications about the pathogenesis and treatment of BPD in preterm human infants.
Collapse
Affiliation(s)
- Kurt H Albertine
- Department of Pediatrics, University of Utah, School of Medicine, Salt Lake City, Utah; Department of Medicine, University of Utah, School of Medicine, Salt Lake City, Utah; and Department of Neurobiology and Anatomy, University of Utah, School of Medicine, Salt Lake City, Utah
| |
Collapse
|
6
|
Chen CH, Chan CC, Chen BY, Cheng TJ, Leon Guo Y. Effects of particulate air pollution and ozone on lung function in non-asthmatic children. ENVIRONMENTAL RESEARCH 2015; 137:40-8. [PMID: 25486544 DOI: 10.1016/j.envres.2014.11.021] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/27/2014] [Revised: 11/06/2014] [Accepted: 11/27/2014] [Indexed: 05/07/2023]
Abstract
INTRODUCTION Information on the long-term effects of different air pollutant levels on lung function is relatively lacking in Asia and still inconclusive in the world. Age differential effects of air pollution are not known. OBJECTIVES To assess the acute and subchronic effects of ambient air pollution on lung function and compared among children of different ages. METHODS From April to May 2011, a nationwide study was conducted on schoolchildren aged 6-15 years in 44 schools of 24 districts in Taiwan. Spirograms were obtained from 1494 non-asthmatic children. Air pollution data were retrieved from air monitoring stations within one kilometre of the schools. Using three-level hierarchical linear models, individual lung function was fitted to air pollution, with adjustments for demographics, indoor exposures, outdoor activity, and districts. RESULTS Lung function changes per inter-quartile increase of the past two-months average levels of particulate matter <2.5 μm (PM2.5) and ozone (12 μg/m(3), 32-44 and 6.7 ppb, 32-38, respectively) were -103 and -142 ml on FVC, -86 and -131 on FEV1, and -102 and -188 ml/s on MMEF, respectively. Lag-1-day ozone exposure was associated with decreased MMEF. In children aged 6-10, PM2.5 was associated with decreased FEV1/FVC and MMEF/FVC ratios. CONCLUSIONS In children aged 6-15 years, sub-chronic exposure to ambient PM2.5 and ozone leads to reduced lung capacity, whereas acute exposure to ozone decreases mid-expiratory flow. In children aged 6-10 years, additional airway obstructive patterns in lung function may be associated with PM2.5 exposure.
Collapse
Affiliation(s)
- Chi-Hsien Chen
- Department of Environmental and Occupational Medicine, National Taiwan University (NTU) College of Medicine and NTU Hospital, Taipei 100, Taiwan
| | - Chang-Chuan Chan
- Department of Environmental and Occupational Medicine, National Taiwan University (NTU) College of Medicine and NTU Hospital, Taipei 100, Taiwan; Institute of Occupational Medicine and Industrial Hygiene, National Taiwan University, Taipei 100, Taiwan
| | - Bing-Yu Chen
- Institute of Occupational Medicine and Industrial Hygiene, National Taiwan University, Taipei 100, Taiwan
| | - Tsun-Jen Cheng
- Institute of Occupational Medicine and Industrial Hygiene, National Taiwan University, Taipei 100, Taiwan
| | - Yue Leon Guo
- Department of Environmental and Occupational Medicine, National Taiwan University (NTU) College of Medicine and NTU Hospital, Taipei 100, Taiwan; Institute of Occupational Medicine and Industrial Hygiene, National Taiwan University, Taipei 100, Taiwan.
| |
Collapse
|
7
|
Murphy SR, Oslund KL, Hyde DM, Miller LA, Van Winkle LS, Schelegle ES. Ozone-induced airway epithelial cell death, the neurokinin-1 receptor pathway, and the postnatal developing lung. Am J Physiol Lung Cell Mol Physiol 2014; 307:L471-81. [PMID: 25063800 DOI: 10.1152/ajplung.00324.2013] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Children are uniquely susceptible to ozone because airway and lung growth continue for an extensive period after birth. Early-life exposure of the rhesus monkey to repeated ozone cycles results in region-specific disrupted airway/lung growth, but the mediators and mechanisms are poorly understood. Substance P (SP), neurokinin-1 receptor (NK-1R); and nuclear receptor Nur77 (NR4A1) are signaling pathway components involved in ozone-induced cell death. We hypothesize that acute ozone (AO) exposure during postnatal airway development disrupts SP/NK-1R/Nur77 pathway expression and that these changes correlate with increased ozone-induced cell death. Our objectives were to 1) spatially define the normal development of the SP/NK-1R/Nur77 pathway in conducting airways; 2) compare how postnatal age modulates responses to AO exposure; and 3) determine how concomitant, episodic ozone exposure modifies age-specific acute responses. Male infant rhesus monkeys were assigned at age 1 mo to two age groups, 2 or 6 mo, and then to one of three exposure subgroups: filtered air (FA), FA+AO (AO: 8 h/day × 2 days), or episodic biweekly ozone exposure cycles (EAO: 8 h/day × 5 days/14-day cycle+AO). O3 = 0.5 ppm. We found that 1) ozone increases SP/NK-1R/Nur77 pathway expression in conducting airways, 2) an ozone exposure cycle (5 days/cycle) delivered early at age 2 mo resulted in an airway that was hypersensitive to AO exposure at the end of 2 mo, and 3) continued episodic exposure (11 cycles) resulted in an airway that was hyposensitive to AO exposure at 6 mo. These observations collectively associate with greater overall inflammation and epithelial cell death, particularly in early postnatal (2 mo), distal airways.
Collapse
Affiliation(s)
- Shannon R Murphy
- Center for Health and the Environment, University of California-Davis, Davis, California
| | - Karen L Oslund
- California National Primate Research Center, University of California-Davis, Davis, California; and
| | - Dallas M Hyde
- California National Primate Research Center, University of California-Davis, Davis, California; and School of Veterinary Medicine, Department of Anatomy, Physiology and Cell Biology, University of California-Davis, Davis, California
| | - Lisa A Miller
- California National Primate Research Center, University of California-Davis, Davis, California; and School of Veterinary Medicine, Department of Anatomy, Physiology and Cell Biology, University of California-Davis, Davis, California
| | - Laura S Van Winkle
- Center for Health and the Environment, University of California-Davis, Davis, California; School of Veterinary Medicine, Department of Anatomy, Physiology and Cell Biology, University of California-Davis, Davis, California
| | - Edward S Schelegle
- California National Primate Research Center, University of California-Davis, Davis, California; and School of Veterinary Medicine, Department of Anatomy, Physiology and Cell Biology, University of California-Davis, Davis, California
| |
Collapse
|
8
|
Hatch GE, Duncan KE, Diaz-Sanchez D, Schmitt MT, Ghio AJ, Carraway MS, McKee J, Dailey LA, Berntsen J, Devlin RB. Progress in assessing air pollutant risks from in vitro exposures: matching ozone dose and effect in human airway cells. Toxicol Sci 2014; 141:198-205. [PMID: 24928893 DOI: 10.1093/toxsci/kfu115] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
In vitro exposures to air pollutants could, in theory, facilitate a rapid and detailed assessment of molecular mechanisms of toxicity. However, it is difficult to ensure that the dose of a gaseous pollutant to cells in tissue culture is similar to that of the same cells during in vivo exposure of a living person. The goal of the present study was to compare the dose and effect of O3 in airway cells of humans exposed in vivo to that of human cells exposed in vitro. Ten subjects breathed labeled O3 ((18)O3, 0.3 ppm, 2 h) while exercising intermittently. Bronchial brush biopsies and lung lavage fluids were collected 1 h post exposure for in vivo data whereas in vitro data were obtained from primary cultures of human bronchial epithelial cells exposed to 0.25-1.0 ppm (18)O3 for 2 h. The O3 dose to the cells was defined as the level of (18)O incorporation and the O3 effect as the fold increase in expression of inflammatory marker genes (IL-8 and COX-2). Dose and effect in cells removed from in vivo exposed subjects were lower than in cells exposed to the same (18)O3 concentration in vitro suggesting upper airway O3 scrubbing in vivo. Cells collected by lavage as well as previous studies in monkeys show that cells deeper in the lung receive a higher O3 dose than cells in the bronchus. We conclude that the methods used herein show promise for replicating and comparing the in vivo dose and effect of O3 in an in vitro system.
Collapse
Affiliation(s)
- Gary E Hatch
- Environmental Public Health Division, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Kelly E Duncan
- Center for Environmental Medicine, Asthma and Lung Biology, School of Medicine, University of North Carolina, Chapel Hill, North Carolina 27599
| | - David Diaz-Sanchez
- Environmental Public Health Division, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Michael T Schmitt
- Environmental Public Health Division, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Andrew J Ghio
- Environmental Public Health Division, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Martha Sue Carraway
- Environmental Public Health Division, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - John McKee
- Environmental Public Health Division, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Lisa A Dailey
- Environmental Public Health Division, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| | - Jon Berntsen
- TRC Environmental Corporation, Raleigh, North Carolina 27606
| | - Robert B Devlin
- Environmental Public Health Division, National Health and Environmental Effects Research Laboratory, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711
| |
Collapse
|
9
|
Peripheral blood neutrophilia as a biomarker of ozone-induced pulmonary inflammation. PLoS One 2013; 8:e81816. [PMID: 24391708 PMCID: PMC3876972 DOI: 10.1371/journal.pone.0081816] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/27/2013] [Accepted: 10/16/2013] [Indexed: 11/19/2022] Open
Abstract
BACKGROUND Ozone concentrations are predicted to increase over the next 50 years due to global warming and the increased release of precursor chemicals. It is therefore urgent that good, reliable biomarkers are available to quantify the toxicity of this pollutant gas at the population level. Such a biomarker would need to be easily performed, reproducible, economically viable, and reflective of ongoing pathological processes occurring within the lung. METHODOLOGY We examined whether blood neutrophilia occurred following a controlled ozone challenge and addressed whether this could serve as a biomarker for ozone-induced airway inflammation. Three separate groups of healthy subjects were exposed to ozone (0.2 ppm, 2h) and filtered air (FA) on two separate occasions. Peripheral blood samples were collected and bronchoscopy with biopsy sampling and lavages was performed at 1.5h post exposures in group 1 (n=13), at 6h in group 2 (n=15) and at 18h in group 3 (n=15). Total and differential cell counts were assessed in blood, bronchial tissue and airway lavages. RESULTS In peripheral blood, we observed fewer neutrophils 1.5h after ozone compared with the parallel air exposure (-1.1±1.0x10(9) cells/L, p<0.01), at 6h neutrophil numbers were increased compared to FA (+1.2±1.3x10(9) cells/L, p<0.01), and at 18h this response had fully attenuated. Ozone induced a peak in neutrophil numbers at 6h post exposure in all compartments examined, with a positive correlation between the response in blood and bronchial biopsies. CONCLUSIONS These data demonstrate a systemic neutrophilia in healthy subjects following an acute ozone exposure, which mirrors the inflammatory response in the lung mucosa and lumen. This relationship suggests that blood neutrophilia could be used as a relatively simple functional biomarker for the effect of ozone on the lung.
Collapse
|
10
|
Hatch GE, McKee J, Brown J, McDonnell W, Seal E, Soukup J, Slade R, Crissman K, Devlin R. Biomarkers of Dose and Effect of Inhaled Ozone in Resting versus Exercising Human Subjects: Comparison with Resting Rats. Biomark Insights 2013; 8:53-67. [PMID: 23761957 PMCID: PMC3663491 DOI: 10.4137/bmi.s11102] [Citation(s) in RCA: 43] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/22/2023] Open
Abstract
To determine the influence of exercise on pulmonary dose of inhaled pollutants, we compared biomarkers of inhaled ozone (O3) dose and toxic effect between exercise levels in humans, and between humans and rats. Resting human subjects were exposed to labeled O3 (18O3, 0.4 ppm, for 2 hours) and alveolar O3 dose measured as the concentration of excess 18O in cells and extracellular material of nasal, bronchial, and bronchoalveolar lavage fluid (BALF). We related O3 dose to effects (changes in BALF protein, LDH, IL-6, and antioxidant substances) measurable in the BALF. A parallel study of resting subjects examined lung function (FEV1) changes following O3. Subjects exposed while resting had 18O concentrations in BALF cells that were 1/5th of those of exercising subjects and directly proportional to the amount of O3 breathed during exposure. Quantitative measures of alveolar O3 dose and toxicity that were observed previously in exercising subjects were greatly reduced or non-observable in O3 exposed resting subjects. Resting rats and resting humans were found to have a similar alveolar O3 dose.
Collapse
Affiliation(s)
- Gary E Hatch
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina
| | | | | | | | | | | | | | | | | |
Collapse
|
11
|
Murphy SR, Schelegle ES, Miller LA, Hyde DM, Van Winkle LS. Ozone exposure alters serotonin and serotonin receptor expression in the developing lung. Toxicol Sci 2013; 134:168-79. [PMID: 23570994 DOI: 10.1093/toxsci/kft090] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022] Open
Abstract
Ozone, a pervasive environmental pollutant, adversely affects functional lung growth in children. Animal studies demonstrate that altered lung development is associated with modified signaling within the airway epithelial mesenchymal trophic unit, including mediators that can change nerve growth. We hypothesized that ozone exposure alters the normal pattern of serotonin, its transporter (5-HTT), and two key receptors (5-HT2A and 5-HT4), a pathway involved in postnatal airway neural, epithelial, and immune processes. We exposed monkeys to acute or episodic ozone during the first 2 or 6 months of life. There were three exposure groups/age: (1) filtered air, (2) acute ozone challenge, and (3) episodic ozone + acute ozone challenge. Lungs were prepared for compartment-specific qRT-PCR, immunohistochemistry, and stereology. Airway epithelial serotonin immunopositive staining increased in all exposure groups with the most prominent in 2-month midlevel and 6-month distal airways. Gene expression of 5-HTT, 5-HT2AR, and 5-HT4R increased in an age-dependent manner. Overall expression was greater in distal compared with midlevel airways. Ozone exposure disrupted both 5-HT2AR and 5-HT4R protein expression in airways and enhanced immunopositive staining for 5-HT2AR (2 months) and 5-HT4R (6 months) on smooth muscle. Ozone exposure increases serotonin in airway epithelium regardless of airway level, age, and exposure history and changes the spatial pattern of serotonin receptor protein (5-HT2A and 5-HT4) and 5-HTT gene expression depending on compartment, age, and exposure history. Understanding how serotonin modulates components of reversible airway obstruction exacerbated by ozone exposure sets the foundation for developing clinically relevant therapies for airway disease.
Collapse
Affiliation(s)
- Shannon R Murphy
- Center for Health and the Environment, California National Primate Research Center, Davis, CA, USA
| | | | | | | | | |
Collapse
|
12
|
Stanek LW, Brown JS, Stanek J, Gift J, Costa DL. Air pollution toxicology--a brief review of the role of the science in shaping the current understanding of air pollution health risks. Toxicol Sci 2010; 120 Suppl 1:S8-27. [PMID: 21147959 DOI: 10.1093/toxsci/kfq367] [Citation(s) in RCA: 93] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Human and animal toxicology has had a profound impact on our historical and current understanding of air pollution health effects. Early animal toxicological studies of air pollution had distinctively military or workplace themes. With the discovery that ambient air pollution episodes led to excess illness and death, there became an emergence of toxicological studies that focused on industrial air pollution encountered by the general public. Not only did the pollutants investigated evolve from ambient mixtures to individual pollutants but also the endpoints and outcomes evaluated became more sophisticated, resulting in our present state of the science. Currently, a large toxicological database exists for the effects of particulate matter and ozone, and we provide a focused review of some of the major contributions to the biological understanding for these two "criteria" air pollutants. A limited discussion of the toxicological advancements in the scientific knowledge of two hazardous air pollutants, formaldehyde and phosgene, is also included. Moving forward, the future challenge of air pollution toxicology lies in the health assessment of complex mixtures and their interactions, given the projected impacts of climate change and altered emissions on ambient conditions. In the coming years, the toxicologist will need to be flexible and forward thinking in order to dissect the complexity of the biological system itself, as well as that of air pollution in all its varied forms.
Collapse
Affiliation(s)
- Lindsay Wichers Stanek
- National Center for Environmental Assessment, Office of Research and Development, US Environmental Protection Agency, Research Triangle Park, North Carolina 27711, USA.
| | | | | | | | | |
Collapse
|
13
|
Carey SA, Ballinger CA, Plopper CG, McDonald RJ, Bartolucci AA, Postlethwait EM, Harkema JR. Persistent rhinitis and epithelial remodeling induced by cyclic ozone exposure in the nasal airways of infant monkeys. Am J Physiol Lung Cell Mol Physiol 2010; 300:L242-54. [PMID: 21131400 DOI: 10.1152/ajplung.00177.2010] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Children chronically exposed to high levels of ozone (O(3)), the principal oxidant pollutant in photochemical smog, are more vulnerable to respiratory illness and infections. The specific factors underlying this differential susceptibility are unknown but may be related to air pollutant-induced nasal alterations during postnatal development that impair the normal physiological functions (e.g., filtration and mucociliary clearance) serving to protect the more distal airways from inhaled xenobiotics. In adult animal models, chronic ozone exposure is associated with adaptations leading to a decrease in airway injury. The purpose of our study was to determine whether cyclic ozone exposure induces persistent morphological and biochemical effects on the developing nasal airways of infant monkeys early in life. Infant (180-day-old) rhesus macaques were exposed to 5 consecutive days of O(3) [0.5 parts per million (ppm), 8 h/day; "1-cycle"] or filtered air (FA) or 11 biweekly cycles of O(3) (FA days 1-9; 0.5 ppm, 8 h/day on days 10-14; "11-cycle"). The left nasal passage was processed for light microscopy and morphometric analysis. Mucosal samples from the right nasal passage were processed for GSH, GSSG, ascorbate (AH(2)), and uric acid (UA) concentration. Eleven-cycle O(3) induced persistent rhinitis, squamous metaplasia, and epithelial hyperplasia in the anterior nasal airways of infant monkeys, resulting in a 39% increase in the numeric density of epithelial cells. Eleven-cycle O(3) also induced a 65% increase in GSH concentrations at this site. The persistence of epithelial hyperplasia was positively correlated with changes in GSH. These results indicate that early life ozone exposure causes persistent nasal epithelial alterations in infant monkeys and provide a potential mechanism for the increased susceptibility to respiratory illness exhibited by children in polluted environments.
Collapse
Affiliation(s)
- Stephan A Carey
- Department of Small Animal Clinical Sciences, College of Veterinary Medicine, Michigan State University, East Lansing, 48824, USA.
| | | | | | | | | | | | | |
Collapse
|
14
|
Backus GS, Howden R, Fostel J, Bauer AK, Cho HY, Marzec J, Peden DB, Kleeberger SR. Protective role of interleukin-10 in ozone-induced pulmonary inflammation. ENVIRONMENTAL HEALTH PERSPECTIVES 2010; 118:1721-7. [PMID: 20826374 PMCID: PMC3002191 DOI: 10.1289/ehp.1002182] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/18/2010] [Accepted: 09/08/2010] [Indexed: 05/09/2023]
Abstract
BACKGROUND The mechanisms underlying ozone (O₃)-induced pulmonary inflammation remain unclear. Interleukin-10 (IL-10) is an anti-inflammatory cytokine that is known to inhibit inflammatory mediators. OBJECTIVES We investigated the molecular mechanisms underlying interleuken-10 (IL-10)-mediated attenuation of O₃-induced pulmonary inflammation in mice. METHODS Il10-deficient (Il10(-/-)) and wild-type (Il10(+/+)) mice were exposed to 0.3 ppm O₃ or filtered air for 24, 48, or 72 hr. Immediately after exposure, differential cell counts and total protein (a marker of lung permeability) were assessed from bronchoalveolar lavage fluid (BALF). mRNA and protein levels of cellular mediators were determined from lung homogenates. We also used global mRNA expression analyses of lung tissue with Ingenuity Pathway Analysis to identify patterns of gene expression through which IL-10 modifies O₃-induced inflammation. RESULTS Mean numbers of BALF polymorphonuclear leukocytes (PMNs) were significantly greater in Il10(-/-) mice than in Il10(+/+) mice after exposure to O₃ at all time points tested. O₃-enhanced nuclear NF-κB translocation was elevated in the lungs of Il10(-/-) compared with Il10(+/+) mice. Gene expression analyses revealed several IL-10-dependent and O₃-dependent mediators, including macrophage inflammatory protein 2, cathepsin E, and serum amyloid A3. CONCLUSIONS Results indicate that IL-10 protects against O₃-induced pulmonary neutrophilic inflammation and cell proliferation. Moreover, gene expression analyses identified three response pathways and several genetic targets through which IL-10 may modulate the innate and adaptive immune response. These novel mechanisms of protection against the pathogenesis of O₃-induced pulmonary inflammation may also provide potential therapeutic targets to protect susceptible individuals.
Collapse
Affiliation(s)
- Gillian S. Backus
- National Institute of Environmental Health Sciences, Laboratory of Respiratory Biology, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
| | - Reuben Howden
- University of North Carolina–Charlotte, Department of Kinesiology, Charlotte, North Carolina, USA
| | - Jennifer Fostel
- National Institute of Environmental Health Sciences, Laboratory of Respiratory Biology, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
| | - Alison K. Bauer
- Michigan State University, Department of Pathobiology and Diagnostic Investigation, Center for Integrative Toxicology, East Lansing, Michigan, USA
| | - Hye-Youn Cho
- National Institute of Environmental Health Sciences, Laboratory of Respiratory Biology, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
| | - Jacqui Marzec
- National Institute of Environmental Health Sciences, Laboratory of Respiratory Biology, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
| | - David B. Peden
- Center for Environmental Medicine, Asthma and Lung Biology, Department of Pediatrics, and Division of Immunology and Infectious Disease, University of North Carolina–Chapel Hill School of Medicine, Chapel Hill, North Carolina, USA
| | - Steven R. Kleeberger
- National Institute of Environmental Health Sciences, Laboratory of Respiratory Biology, National Institutes of Health, Department of Health and Human Services, Research Triangle Park, North Carolina, USA
- Address correspondence to S.R. Kleeberger, 111 T.W. Alexander Dr., Bldg. 101, MD-201, National Institute of Environmental Health Sciences, Research Triangle Park, NC 27709 USA. Telephone: (919) 541-3267. Fax: (919) 541-3592. E-mail:
| |
Collapse
|
15
|
Cole MP, Freeman BA. Promotion of cardiovascular disease by exposure to the air pollutant ozone. Am J Physiol Lung Cell Mol Physiol 2009; 297:L205-8. [PMID: 19525390 DOI: 10.1152/ajplung.00187.2009] [Citation(s) in RCA: 11] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
|
16
|
Livraghi A, Grubb BR, Hudson EJ, Wilkinson KJ, Sheehan JK, Mall MA, O'Neal WK, Boucher RC, Randell SH. Airway and lung pathology due to mucosal surface dehydration in {beta}-epithelial Na+ channel-overexpressing mice: role of TNF-{alpha} and IL-4R{alpha} signaling, influence of neonatal development, and limited efficacy of glucocorticoid treatment. THE JOURNAL OF IMMUNOLOGY 2009; 182:4357-67. [PMID: 19299736 DOI: 10.4049/jimmunol.0802557] [Citation(s) in RCA: 73] [Impact Index Per Article: 4.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/13/2023]
Abstract
Overexpression of the epithelial Na(+) channel beta subunit (Scnn1b gene, betaENaC protein) in transgenic (Tg) mouse airways dehydrates mucosal surfaces, producing mucus obstruction, inflammation, and neonatal mortality. Airway inflammation includes macrophage activation, neutrophil and eosinophil recruitment, and elevated KC, TNF-alpha, and chitinase levels. These changes recapitulate aspects of complex human obstructive airway diseases, but their molecular mechanisms are poorly understood. We used genetic and pharmacologic approaches to identify pathways relevant to the development of Scnn1b-Tg mouse lung pathology. Genetic deletion of TNF-alpha or its receptor, TNFR1, had no measurable effect on the phenotype. Deletion of IL-4Ralpha abolished transient mucous secretory cell (MuSC) abundance and eosinophilia normally observed in neonatal wild-type mice. Similarly, IL-4Ralpha deficiency decreased MuSC and eosinophils in neonatal Scnn1b-Tg mice, which correlated with improved neonatal survival. However, chronic lung pathology in adult Scnn1b-Tg mice was not affected by IL-4Ralpha status. Prednisolone treatment ablated eosinophilia and MuSC in adult Scnn1b-Tg mice, but did not decrease mucus plugging or neutrophilia. These studies demonstrate that: 1) normal neonatal mouse airway development entails an IL-4Ralpha-dependent, transient abundance of MuSC and eosinophils; 2) absence of IL-4Ralpha improved neonatal survival of Scnn1b-Tg mice, likely reflecting decreased formation of asphyxiating mucus plugs; and 3) in Scnn1b-Tg mice, neutrophilia, mucus obstruction, and airspace enlargement are IL-4Ralpha- and TNF-alpha-independent, and only MuSC and eosinophilia are sensitive to glucocorticoids. Thus, manipulation of multiple pathways will likely be required to treat the complex pathogenesis caused by airway surface dehydration.
Collapse
Affiliation(s)
- Alessandra Livraghi
- Cystic Fibrosis/Pulmonary Research and Treatment Center, The University of North Carolina at Chapel Hill, 27599, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
17
|
Subke JA, Toet S, D'Haese D, Crossman Z, Emberson LD, Barnes JD, Ashmore MR, Evershed RP, Ineson P. A new method for using 18O to trace ozone deposition. RAPID COMMUNICATIONS IN MASS SPECTROMETRY : RCM 2009; 23:980-984. [PMID: 19241413 DOI: 10.1002/rcm.3961] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/27/2023]
Abstract
Isotopically labelled ozone ((18)O(3)) is an ideal tool to study the deposition of O(3) to plants and soil, but no studies have made use of it due to the technical difficulties in producing isotopically enriched ozone. For (18)O(3) to be used in fumigation experiments, it has to be purified and stored safely prior to fumigations, to ensure that the label is present predominantly in the form of O(3), and to make efficient use of isotopically highly enriched oxygen. We present a simple apparatus that allows for the safe generation, purification, storage, and release of (18)O(3). Following the purification and release of O(3), about half (by volume) of the (18)O is present in the form of O(3). This means that for a given release of (18)O(3) into the fumigation system, a roughly identical volume of (18)O(2) is released. However, the small volume of this concurrent (18)O(2) release (100 nmol mol(-1) in our experiment) results in only a minor shift of the much larger atmospheric oxygen pool, with no detectable consequence for the isotopic enrichment of either soil or plant materials. We demonstrate here the feasibility of using (18)O as an isotopic tracer in O(3) fumigations by exposing dry soil to 100 nmol mol(-1) (18)O(3) for periods ranging from 1 to 11 h. The (18)O tracer accumulation in soil samples is measured using gas chromatography/isotope ratio mass spectrometry (GC/IRMS), and the results show a linear increase in (18)O/(16)O isotope ratio over time, with significant differences detectable after 1 h of exposure. The apparatus is adapted for use with fumigation chambers sustaining flow rates of 1 m(3) min(-1) for up to 12 h, but simple modifications now allow larger quantities of O(3) to be stored and continuously released (e.g. for use with open-top chambers or FACE facilities).
Collapse
Affiliation(s)
- Jens-Arne Subke
- Stockholm Environment Institute, University of York, York YO10 5DD, UK.
| | | | | | | | | | | | | | | | | |
Collapse
|
18
|
Madasu S, Borhan A, Ultman J. Gas Uptake in a Three-Generation Model Geometry During Steady Expiration: Comparison of Axisymmetric and Three-Dimensional Models. Inhal Toxicol 2008; 19:199-210; discussion 211-2. [PMID: 17365024 DOI: 10.1080/08958370601067855] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Mass transfer coefficients were predicted and compared for uptake of a formaldehyde-air gas system using an axisymmetric single path model (ASPM) and a three-dimensional computational fluid dynamics model (CFDM) in three-generation model geometry at steady expiratory flow. The flow and concentration fields in the ASPM were solved using Galerkin's finite-element method and in the CFDM using a commercial finite-element software, FIDAP. Numerical results were compared for two different inlet flow rates, wall mass transfer coefficients, and bifurcation angles. The mass transfer coefficients variation with bifurcation unit from the ASPM and CFDM compared qualitatively and quantitatively closely at all flows and lower wall mass transfer coefficients for both 40 degrees and 70 degrees bifurcation angles. However, at higher wall mass transfer coefficients, quantitatively they were within 40% for both the bifurcation angles. Also, at higher flow and wall mass transfer coefficients, they were off qualitatively for a 70 degrees bifurcation angle although the uptake compared qualitatively. This is due to the normalization of uptake within a bifurcation unit with the average of inlet and outlet average concentrations. Both CFDM and ASPM predict the same trends of increase in mass transfer coefficients with inlet flow and wall mass transfer coefficients. Also, the local values of the mass transfer coefficients compared closely at all conditions. These results validate the simplified ASPM and the complex CFDM. Mass transfer coefficients increase with bifurcation angles and with a flat inlet velocity profile compared to a parabolic velocity profile since the flow is non-fully developed and hence, the uptake increases.
Collapse
|
19
|
Madasu S, Borhan A, Ultman J. Gas Uptake in a Three-Generation Model Geometry with a Flat Inlet Velocity During Steady Inspiration: Comparison of Axisymmetric and Three-Dimensional Models. Inhal Toxicol 2008; 19:495-503. [PMID: 17497528 DOI: 10.1080/08958370701271704] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/23/2022]
Abstract
Mass transfer coefficients were predicted and compared for uptake of reactive gas system using an axisymmetric single-path model (ASPM) with experimentally predicted values in a two-generation geometry and with a three-dimensional computational fluid dynamics model (CFDM) in a three-generation model geometry at steady inspiratory flow with a flat inlet velocity profile. The flow and concentration fields in the ASPM were solved using Galerkin's finite element method and in the CFDM using a commercial finite element software FIDAP. ASPM predicted average gas phase mass transfer coefficients within 25% of the experimental values. Numerical results in terms of overall mass transfer coefficients from the two models within each bifurcation unit were compared for two different inlet flow rates, wall mass transfer coefficients, and bifurcation angles. The overall mass transfer coefficients variation with bifurcation unit from the ASPM and CFDM compared qualitatively and quantitatively closely at lower wall mass transfer coefficients for both 40 degree and 70 degree bifurcation angles. But at higher wall mass transfer coefficients, quantitatively they were off in the range of 2-10% for 40 degree bifurcation angle and in the range of 4-15% for 70 degree bifurcation angle. Both CFDM and ASPM predict the same trends of increase in mass transfer coefficients with inlet flow, wall mass transfer coefficients, and during inspiration compared to expiration. Higher mass transfer coefficients were obtained with a flat velocity profile compared to a parabolic velocity profile using ASPM. These results validate the simplified ASPM and the complex CFDM.
Collapse
|
20
|
Interleukin (IL)-1 regulates ozone-enhanced tracheal smooth muscle responsiveness by increasing substance P (SP) production in intrinsic airway neurons of ferret. Respir Physiol Neurobiol 2008; 164:300-11. [PMID: 18718561 DOI: 10.1016/j.resp.2008.07.019] [Citation(s) in RCA: 17] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/14/2007] [Revised: 07/14/2008] [Accepted: 07/15/2008] [Indexed: 11/20/2022]
Abstract
Exposure to ozone induces airway hyperresponsiveness (AHR) mediated partly by substance P (SP) released from nerve terminals of intrinsic airway neurons. Our recent studies showed that interleukin (IL)-1, an important multifunctional proinflammatory cytokine, increases synthesis and release of SP from intrinsic airway neurons. The purpose of this study is to investigate the possible involvement of endogenous IL-1 in modulating neural responses associated with ozone-enhanced airway responsiveness. Ferrets were exposed to 2ppm ozone or filtered air for 3h. IL-1 in the bronchoalveolar lavage (BAL) fluid was significantly increased in ozone-exposed animals and responses of tracheal smooth muscle to methacholine (MCh) and electrical field stimulation (EFS) were elevated significantly. Both the SP nerve fiber density in tracheal smooth muscle and the number of SP-containing neurons in airway ganglia were significantly increased following ozone exposure. Pretreatment with IL-1 receptor antagonist (IL-1 Ra) significantly diminished ozone-enhanced airway responses to EFS as well as ozone-increased SP in the airway. To selectively investigate intrinsic airway neurons, segments of ferret trachea were maintained in culture conditions for 24h to eliminate extrinsic contributions from sensory nerves. The segments were then exposed to 2ppm ozone in vitro for 3h. The changes of ozone-induced airway responses to MCh and EFS, and the SP levels in airway neurons paralleled those observed with in vivo ozone exposure. The ozone-enhanced airway responses and neuronal SP levels were inhibited by pretreatment with IL-1 Ra. These findings show that IL-1 is released during ozone exposure enhances airway responsiveness by modulating SP expression in airway neurons.
Collapse
|
21
|
Madasu S, Ultman JS, Borhan A. Comparison of Axisymmetric and Three-Dimensional Models for Gas Uptake in a Single Bifurcation During Steady Expiration. J Biomech Eng 2008; 130:011013. [DOI: 10.1115/1.2838041] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Reactive gas uptake is predicted and compared in a single bifurcation at steady expiratory flow in terms of Sherwood number using an axisymmetric single-path model (ASPM) and a three-dimensional computational fluid dynamics model (CFDM). ASPM is validated in a two-generation geometry by comparing the average gas-phase mass transfer coefficients with the experimental values. ASPM predicted mass transfer coefficients within 20% of the experimental values. The flow and concentration variables in the ASPM were solved using Galerkin finite element method and in the CFDM using commercial finite element software FIDAP. The simulations were performed for reactive gas flowing at Reynolds numbers ranging from 60 to 350 in both symmetric bifurcation for three bifurcation angles, 30deg, 70deg, and 90deg, and in an asymmetric bifurcation. The numerical models compared with each other qualitatively but quantitatively they were within 0.4–8% due to nonfully developed flow in the parent branch predicted by the CFDM. The radially averaged concentration variation along the axial location matched qualitatively between the CFDM and ASPM but quantitatively they were within 32% due to differences in the flow field. ASPM predictions compared well with the CFDM predictions for an asymmetric bifurcation. These results validate the simplified ASPM and the complex CFDM. ASPM predicts higher Sherwood number with a flat velocity inlet profile compared to a parabolic inlet velocity profile. Sherwood number increases with the inlet average velocity, wall mass transfer coefficient, and bifurcation angle since the boundary layer grows slower in the parent and daughter branches.
Collapse
Affiliation(s)
- Srinath Madasu
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802
| | - James S. Ultman
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802
| | - Ali Borhan
- Department of Chemical Engineering, The Pennsylvania State University, University Park, PA 16802
| |
Collapse
|
22
|
Abstract
This review evaluates the current status of information regarding the nonhuman primate as an experimental model for defining mechanisms of chronic airways disease in humans, using the concept of the epithelial-mesenchymal trophic unit (EMTU) as a basis for comparison with other laboratory species. All of the cellular and acellular compartments within the walls of tracheobronchial airways which interact as the EMTU are present throughout the airway tree in human and nonhuman primates. The epithelial compartment contains mucous goblet and basal cells in the surface epithelium and submucosal glands within the wall. The interstitial compartment of primates has a prominent subepithelial basement membrane zone (BMZ) with an attenuated fibroblast sheath and cartilage throughout the tree. In primates, there is an extensive transition zone between distal conducting airways and lung parenchyma composed of numerous generations of respiratory bronchioles. None of these features are characteristic of intrapulmonary airways in rodents, whose airways do share ciliated cells, smooth muscle cells, nerve networks, vasculature and inflammatory cell populations with primates. While the numbers of intrapulmonary airway branches are similar for most mammals, branching patterns, which dictate distribution of inhaled materials, are more uniform (dichotomous) in primates and less so (monopodial) in rodents. Development of tracheobronchial airways (both differentiation of the EMTU and overall growth) occurs over an extensive postnatal period (months to years) in primates and a comparably shorter time period (2-3 weeks) in rodents. As with allergic airways disease in humans, experimental exposure of nonhuman primates to a known human allergen, house dust mite, produces extensive remodeling of all compartments of the EMTU: mucous goblet cell hyperplasia, epithelial sloughing, basement membrane zone (BMZ) thickening and reorganization, altered attenuated fibroblast function, subepithelial fibrosis and smooth muscle thickening. Experimental allergic airways disease in nonhuman primates also shares other features with asthmatic humans: positive skin test to allergen; allergen-specific circulating IgE; airway hyper responsiveness to allergen, histamine and methacholine; increased eosinophils, IGE positive cells and mucins in airway exudate; and migratory leukocyte accumulations in the airway wall and lumen. Experimental exposure of nonhuman primates to reactive gases, such as ozone, produces the chronic respiratory bronchiolitis and other airway alterations associated with restricted airflow and chronic respiratory bronchiolitis characteristic of COPD in young smokers. We conclude that nonhuman primate models are appropriate for defining mechanisms as they relate to allergic airways disease and COPD in humans.
Collapse
Affiliation(s)
- Charles G Plopper
- California National Primate Research Center and School of Veterinary Medicine, University of California, One Shields Avenue, Davis, CA 95616, USA.
| | | |
Collapse
|
23
|
Haque R, Umstead TM, Ponnuru P, Guo X, Hawgood S, Phelps DS, Floros J. Role of surfactant protein-A (SP-A) in lung injury in response to acute ozone exposure of SP-A deficient mice. Toxicol Appl Pharmacol 2006; 220:72-82. [PMID: 17307210 PMCID: PMC1906716 DOI: 10.1016/j.taap.2006.12.017] [Citation(s) in RCA: 55] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Revised: 12/01/2006] [Accepted: 12/02/2006] [Indexed: 10/23/2022]
Abstract
Millions are exposed to ozone levels above recommended limits, impairing lung function, causing epithelial damage and inflammation, and predisposing some individuals to pneumonia, asthma, and other lung conditions. Surfactant protein-A (SP-A) plays a role in host defense, the regulation of inflammation, and repair of tissue damage. We tested the hypothesis that the lungs of SP-A(-/-) (KO) mice are more susceptible to ozone-induced damage. We compared the effects of ozone on KO and wild type (WT) mice on the C57BL/6 genetic background by exposing them to 2 parts/million of ozone for 3 or 6 h and sacrificing them 0, 4, and 24 h later. Lungs were subject to bronchoalveolar lavage (BAL) or used to measure endpoints of oxidative stress and inflammation. Despite more total protein in BAL of KO mice after a 3 h ozone exposure, WT mice had increased oxidation of protein and had oxidized SP-A dimers. In KO mice there was epithelial damage as assessed by increased LDH activity and there was increased phospholipid content. In WT mice there were more BAL PMNs and elevated macrophage inflammatory protein (MIP)-2 and monocyte chemoattractant protein (MCP)-1. Changes in MIP-2 and MCP-1 were observed in both KO and WT, however mRNA levels differed. In KO mice MIP-2 mRNA levels changed little with ozone, but in WT levels they were significantly increased. In summary, several aspects of the inflammatory response differ between WT and KO mice. These in vivo findings appear to implicate SP-A in regulating inflammation and limiting epithelial damage in response to ozone exposure.
Collapse
Affiliation(s)
- Rizwanul Haque
- Departments of Pediatrics, Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Todd M. Umstead
- Departments of Pediatrics, Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Padmavathi Ponnuru
- Departments of Pediatrics, Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Xiaoxuan Guo
- Departments of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Samuel Hawgood
- Department of Pediatrics and Cardiovascular Research Institute, University of California, San Francisco, CA 94143
| | - David S. Phelps
- Departments of Pediatrics, Pennsylvania State University College of Medicine, Hershey, PA 17033
| | - Joanna Floros
- Departments of Pediatrics, Pennsylvania State University College of Medicine, Hershey, PA 17033
- Departments of Cellular and Molecular Physiology, Pennsylvania State University College of Medicine, Hershey, PA 17033
- Departments of Obstetrics and Gynecology, Pennsylvania State University College of Medicine, Hershey, PA 17033
| |
Collapse
|
24
|
Plopper CG, Mango GW, Hatch GE, Wong VJ, Toskala E, Reynolds SD, Tarkington BK, Stripp BR. Elevation of susceptibility to ozone-induced acute tracheobronchial injury in transgenic mice deficient in Clara cell secretory protein. Toxicol Appl Pharmacol 2006; 213:74-85. [PMID: 16226776 DOI: 10.1016/j.taap.2005.09.003] [Citation(s) in RCA: 19] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/24/2005] [Revised: 08/29/2005] [Accepted: 09/06/2005] [Indexed: 10/25/2022]
Abstract
Increases in Clara cell abundance or cellular expression of Clara cell secretory protein (CCSP) may cause increased tolerance of the lung to acute oxidant injury by repeated exposure to ozone (O3). This study defines how disruption of the gene for CCSP synthesis affects the susceptibility of tracheobronchial epithelium to acute oxidant injury. Mice homozygous for a null allele of the CCSP gene (CCSP-/-) and wild type (CCSP+/+) littermates were exposed to ozone (0.2 ppm, 8 h; 1 ppm, 8 h) or filtered air. Injury was evaluated by light and scanning electron microscopy, and the abundance of necrotic, ciliated, and nonciliated cells was estimated by morphometry. Proximal and midlevel intrapulmonary airways and terminal bronchioles were evaluated. There was no difference in airway epithelial composition between CCSP+/+ and CCSP-/- mice exposed to filtered air, and exposure to 0.2 ppm ozone caused little injury to the epithelium of both CCSP+/+ and CCSP-/- mice. After exposure to 1.0 ppm ozone, CCSP-/- mice suffered from a greater degree of epithelial injury throughout the airways compared to CCSP+/+ mice. CCSP-/- mice had both ciliated and nonciliated cell injury. Furthermore, lack of CCSP was associated with a shift in airway injury to include proximal airway generations. Therefore, we conclude that CCSP modulates the susceptibility of the epithelium to oxidant-induced injury. Whether this is due to the presence of CCSP on the acellular lining layer surface and/or its intracellular distribution in the secretory cell population needs to be defined.
Collapse
Affiliation(s)
- C G Plopper
- Department of Anatomy, Physiology and Cell Biology, California National Primate Center, School of Veterinary Medicine, 1 Shields Avenue, University of California, Davis, CA 95616, USA.
| | | | | | | | | | | | | | | |
Collapse
|
25
|
Ratto J, Wong H, Liu J, Fahy J, Boushey H, Solomon C, Balmes J. Effects of multiday exposure to ozone on airway inflammation as determined using sputum induction. ENVIRONMENTAL HEALTH PERSPECTIVES 2006; 114:209-12. [PMID: 16451856 PMCID: PMC1367833 DOI: 10.1289/ehp.8341] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 05/06/2023]
Abstract
Single short-term exposures to ozone are known to cause acute changes in pulmonary function and neutrophilic airway inflammation. The respiratory health effects of repeated exposures are not as well studied. Pulmonary function decrements are known to attenuate, but it is less clear how injury and inflammation are affected. Using sputum induction (SI) to sample respiratory tract lining fluid after single- and multiday exposures, we designed a study to test the hypothesis that neutrophils would increase after multiday exposure compared with single-day exposure. In a randomized, crossover design, 15 normal healthy subjects were exposed to O3 (0.2 ppm) under two conditions: for 4 hr for 1 day (1D) and for 4 hr for 4 consecutive days (4D). Pulmonary function testing was performed immediately before and after each 4-hr exposure. The SI was performed 18 hr after the end of the 1D and 4D conditions. The symptom and pulmonary function data followed a pattern seen in other multiday O3 exposure studies, with the greatest changes occurring on the second day. In contrast to previous studies using bronchoalveolar lavage, however, there was a significant increase in the percentage of neutrophils and a significant decrease in the percentage of macrophages after the 4D condition compared with the 1D condition. Given that SI likely samples proximal airways better than distal lung, these results add to the body of evidence that differential airway compartmental responses to O3 occur in humans and other species.
Collapse
Affiliation(s)
- Jeffrey Ratto
- Lung Biology Center, University of California San Francisco, San Francisco, California 94143-0843, USA
| | | | | | | | | | | | | |
Collapse
|
26
|
Tran MUT, Weir AJ, Fanucchi MV, Murphy AE, Van Winkle LS, Evans MJ, Smiley-Jewell SM, Miller L, Schelegle ES, Gershwin LJ, Hyde DM, Plopper CG. Smooth muscle development during postnatal growth of distal bronchioles in infant rhesus monkeys. J Appl Physiol (1985) 2004; 97:2364-71; discussion 2354. [PMID: 15347627 DOI: 10.1152/japplphysiol.00476.2004] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Development of smooth muscle in conducting airways begins early in fetal life. Whereas the pattern and regulation of smooth muscle differentiation are well-defined, the impact of airway growth on the process is not. To evaluate the transformations in organization during postnatal growth, smooth muscle bundle organization (size, abundance, and orientation) was mapped in five generations of distal airways of infant rhesus monkeys (5 days and 1, 2, 3, and 6 mo old). On the basis of direct measurement of the bronchiole proximal to the terminal bronchiole, length increased by 2-fold, diameter by 1.35-fold, and surface area by 2.8-fold between 5 days and 6 mo of age. Smooth muscle bundle size was greater in proximal bronchioles than in respiratory bronchioles and did not change with age. However, relative bundle size decreased in proportion to airway size as the airways grew. Relative bundle abundance was constant regardless of airway generation or age. The distribution of smooth muscle bundle orientation changed with age in each airway generation, and there were significant changes in the terminal and respiratory bronchioles. We conclude that smooth muscle undergoes marked organizational changes as airways grow during postnatal development.
Collapse
Affiliation(s)
- Mai-Uyen T Tran
- Dept. of Anatomy, Physiology, and Cell Biology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
27
|
Van Winkle LS, Fanucchi MV, Miller LA, Baker GL, Gershwin LJ, Schelegle ES, Hyde DM, Evans MJ, Plopper CG. Epithelial cell distribution and abundance in rhesus monkey airways during postnatal lung growth and development. J Appl Physiol (1985) 2004; 97:2355-63; discussion 2354. [PMID: 15298983 DOI: 10.1152/japplphysiol.00470.2004] [Citation(s) in RCA: 26] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022] Open
Abstract
Lung development is both a pre- and postnatal process. Although many lung diseases have their origins in early childhood, few quantitative data are available on the normal growth and differentiation of both the conducting airways and the airway epithelium during the postnatal period. We examined rhesus monkey lungs from five postnatal ages: 4-6 days and 1, 2, 3, and 6 mo. Airways increase significantly in both length and circumference as monkeys increase significantly in body weight from 5 days to 6 mo. In this study we asked: as basement membrane surface area increases, does the epithelial cell organization change? To answer this question, we quantified total epithelial cell mass using high-resolution light micrographs and morphometric techniques on sections from defined airway regions: trachea, proximal intrapulmonary bronchus (generations 1 or 2), and distal intrapulmonary bronchus (generations 6-8). Epithelial thickness decreased in the smaller, more distal, airways compared with trachea but did not change with age in the trachea and proximal bronchus. The volume fraction of all cell types measured did not change significantly. Ciliated cells in the distal bronchus and goblet cells in the trachea both decreased in abundance with increasing age. Overall, the epithelial cell populations changed little in terms of mass or relative abundance to each other during this period of active postnatal lung growth. Regarding the proximal conducting airway epithelium, we conclude that 1) the steady-state abundance is tightly regulated to keep the proportion of cell types constant, and 2) establishment of these cell types occurs before 4-6 days postnatal age. We conclude that growth of the proximal airways occurs primarily in length and lags behind that of the lung parenchyma.
Collapse
Affiliation(s)
- Laura S Van Winkle
- Dept. of Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California-Davis, Davis, CA 95616-8732, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|
28
|
Abstract
Ozone (O3) is an air pollutant produced by sunlight-driven reactions involving the oxides of nitrogen and volatile organic compounds. The population of many large metropolitan areas in the US is exposed to high levels of O3, particularly in the summer months. Individuals exposed to O3 levels in human experiments at higher than common ambient levels develop reversible reductions in lung function often associated with symptoms, such as airway hyperreactivity and lung inflammation. Animal models have helped characterize potential mechanisms of lung injury from O3 exposure. Defining the adverse effects of chronic exposure to ambient levels of O3 on lung function and disease have been challenging, in part due to the presence of co-pollutants, such as particulate matter. The US Environmental Protection Agency's 1997 revised standard for O3 (0.08 ppm averaged over 8 hours) is designed to provide better protection to susceptible individuals. The revised standard is being implemented following the failure of court challenges.
Collapse
Affiliation(s)
- Nevin Uysal
- Department of Internal Medicine, Division of Pulmonary and Critical Care Medicine, Medical College of Wisconsin and Zablocki Veterans Affairs Medical Center, Milwaukee, 53295, USA.
| | | |
Collapse
|
29
|
El-Chemaly S, Salathe M, Baier S, Conner GE, Forteza R. Hydrogen peroxide-scavenging properties of normal human airway secretions. Am J Respir Crit Care Med 2003; 167:425-30. [PMID: 12446267 DOI: 10.1164/rccm.200206-531oc] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
To examine the antioxidant capacity of normal human airway secretions and to characterize its molecular components, tracheal lavages were obtained from eight patients intubated for elective surgery and free of lung disease. These samples (20 microl, approximately 6.8 microg of protein) scavenged 0.57 +/- 0.09 nmol of added 0.96 nmol hydrogen peroxide (H2O2) within 10 minutes at room temperature (n = 8). The scavenging activity was inhibited 60 +/- 4% by azide (an inhibitor of heme-containing peroxidases and catalase) and 42 +/- 9% by dapsone (an inhibitor of lactoperoxidase). Mercaptosuccinic acid (an inhibitor of glutathione peroxidase) did not significantly inhibit H2O2 scavenging by these secretions. Fourfold diluted secretions showed only nonenzymatic scavenging activity, but the addition of thiocyanate to these samples (0.4 mM; substrate for lactoperoxidase) restored their ability to scavenge H2O2. The addition of reduced glutathione (8 microM) only enhanced nonenzymatic scavenging activity. These data provide evidence that multiple enzymatic and nonenzymatic systems coexist in human airway secretions that contribute to H2O2 scavenging. It appears, however, that H2O2 is mainly consumed by the lactoperoxidase system.
Collapse
Affiliation(s)
- Souheil El-Chemaly
- Division of Pulmonary and Critical Care Medicine, Department of Anesthesiology, University of Miami School of Medicine, Miami, Florida 33136, USA
| | | | | | | | | |
Collapse
|
30
|
Romieu I, Sienra-Monge JJ, Ramírez-Aguilar M, Téllez-Rojo MM, Moreno-Macías H, Reyes-Ruiz NI, del Río-Navarro BE, Ruiz-Navarro MX, Hatch G, Slade R, Hernández-Avila M. Antioxidant supplementation and lung functions among children with asthma exposed to high levels of air pollutants. Am J Respir Crit Care Med 2002; 166:703-9. [PMID: 12204869 DOI: 10.1164/rccm.2112074] [Citation(s) in RCA: 196] [Impact Index Per Article: 8.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
To evaluate whether acute effects of ozone, nitrogen dioxide, and particulates with mass median diameter less than 10 micro m could be attenuated by antioxidant vitamin supplementation, we conducted a randomized trial using a double-blinded design. Children with asthma (n = 158) who were residents of Mexico City were randomly given a daily supplement of vitamins (50 mg/day of vitamin E and 250 mg/day of vitamin C) or a placebo and were followed from October 1998 to April 2000. Pulmonary function tests were carried out twice a week in the morning. During the follow-up observation period, the mean 1-hour maximum ozone level was 102 ppb (SD = 47), and the mean 24-hour average PM(10) level was 56.7 micro g/m(3) (SD = 27.4). In children with moderate and severe asthma, ozone levels 1 day before spirometry were inversely associated significantly with forced expiratory flow (FEF(25-75)) (-13.32 ml/second/10 ppb; p = 0.000), FEV(1) (-4.59 ml/10 ppb; p = 0.036), and peak expiratory flow (PEF) (-15.01 ml/second/10 ppb; p = 0.04) in the placebo group after adjusting for potential confounding factors. No association between ozone and lung functions was observed in the supplement group. We observed significant differences in lung function decrements between groups for FEF(25-75) and PEF. Our results suggest that supplementation with antioxidants might modulate the impact of ozone exposure on the small airways of children with moderate to severe asthma.
Collapse
Affiliation(s)
- Isabelle Romieu
- Instituto Nacional de Salud Publica, Cuernavaca, Morelos, Mexico.
| | | | | | | | | | | | | | | | | | | | | |
Collapse
|
31
|
Ray S, Watkins DN, Misso NLA, Thompson PJ. Oxidant stress induces gamma-glutamylcysteine synthetase and glutathione synthesis in human bronchial epithelial NCI-H292 cells. Clin Exp Allergy 2002; 32:571-7. [PMID: 11972604 DOI: 10.1046/j.0954-7894.2002.01294.x] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
BACKGROUND The bronchial epithelium is exposed to reactive oxygen species (ROS) derived from cigarette smoke, air pollutants and activated leucocytes. Glutathione (GSH) prevents ROS-mediated loss of cell function, tissue injury and inflammation, and its synthesis is regulated by gamma-glutamylcysteine synthetase (gamma-GCS). However, the capacity of bronchial epithelial cells to adapt to oxidative stress and the mechanisms involved are not known. OBJECTIVE To investigate the effects of oxidative stress on the regulation of GSH synthesis in human bronchial epithelial (NCI-H292) cells. METHODS NCI-H292 cells were exposed to menadione and intracellular GSH concentrations were measured by spectrophotometry. gamma-GCS activity was measured by HPLC assay and changes in gamma-GCS mRNA by Northern blotting. RESULTS Exposure to menadione (MQ, 10-200 microm, 30-120 min) decreased total cellular GSH content, measured immediately after exposure to MQ. However, GSH content measured 6-12 h after withdrawal of the oxidant stress (MQ, 50 microm, 30 min), increased c. two fold over baseline levels (P < 0.001). gamma-GCS activity measured 6 h (21.7 +/- 3.4 nmol/min/mg, SD, n = 5, P < 0.01) or 12 h (23.2 +/- 4.6, P < 0.001) after MQ treatment was also significantly increased compared with untreated cells (12.8 +/- 1.0). Similarly, gamma-GCS mRNA expression increased 1.3-1.6-fold relative to GAPDH mRNA, 3-6 h after MQ treatment. The MQ-induced increase in gamma-GCS mRNA expression was completely inhibited by actinomycin D. CONCLUSIONS Bronchial epithelial (NCI-H292) cells respond rapidly and sensitively to oxidant stress, and this adaptive response is mediated by increased gamma-GCS mRNA transcription and enzyme activity.
Collapse
Affiliation(s)
- S Ray
- Asthma and Allergy Research Institute, and Department of Medicine, The University of Western Australia, Perth, Australia
| | | | | | | |
Collapse
|
32
|
Huffman LJ, Judy DJ, Brumbaugh K, Frazer DG, Reynolds JS, McKinney WG, Goldsmith WT. Hyperthyroidism Increases the Risk of Ozone-Induced Lung Toxicity in Rats. Toxicol Appl Pharmacol 2001; 173:18-26. [PMID: 11350211 DOI: 10.1006/taap.2001.9174] [Citation(s) in RCA: 15] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
The risk of lung injury from ozone exposure has been well documented. It is also known that various factors may significantly influence the susceptibility of animals to the toxic effects of ozone. In the present study, we investigated the possibility that hyperthyroidism might be associated with increases in ozone-induced pulmonary toxicity. To create a hyperthyroid condition, mature male Sprague--Dawley rats were given injections of thyroxine (dose range: 0.1 to 1 mg/kg body wt daily for 7 days). Control rats received vehicle injections. The animals were then exposed to air or ozone (dose range: 0.5 to 3 ppm for 3 h). At 18 h postexposure, bronchoalveolar lavage fluid and cells were harvested. In hyperthyroid animals, ozone exposure was associated with three- to sixfold increases in bronchoalveolar lavage fluid lactate dehydrogenase activities and albumin levels as well as the number of polymorphonuclear leukocytes harvested by bronchoalveolar lavage above levels observed in ozone-exposed control rats. Additional results from the present study suggest that these thyroid hormone-linked effects cannot be fully explained by differences in whole-body metabolic rate or changes in the inhaled dose of ozone. These findings indicate that the risk of ozone-induced lung toxicity is substantially increased in a hyperthyroid state and suggest that the susceptibility of the lung to damage from ozone exposure may be significantly influenced by individual thyroid hormone status.
Collapse
Affiliation(s)
- L J Huffman
- Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia 26505, USA
| | | | | | | | | | | | | |
Collapse
|
33
|
Liu RM, Borok Z, Forman HJ. 4-Hydroxy-2-nonenal increases gamma-glutamylcysteine synthetase gene expression in alveolar epithelial cells. Am J Respir Cell Mol Biol 2001; 24:499-505. [PMID: 11306445 DOI: 10.1165/ajrcmb.24.4.4307] [Citation(s) in RCA: 225] [Impact Index Per Article: 9.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
Previous studies from this laboratory demonstrated that 4-hydroxy-2-nonenal (4HNE), a lipid peroxidation product, induces expression of gamma-glutamylcysteine synthetase (GCS), the rate-limiting enzyme in de novo glutathione (GSH) synthesis, in rat alveolar epithelial L2 cells. The present study demonstrates that 4HNE also induces GCS in primary cultured alveolar epithelial type II (AT2) cells. Enzyme activity, protein content, and messenger RNA levels of both the catalytic (GCS-HS) and regulatory (GCS-LS) subunits were significantly increased in AT2 cells treated with 5 or 10 microM 4HNE, the same concentrations that induced GCS expression in L2 cells. As in L2 cells, 4HNE induced a greater AT2-cell increase in GCS-LS than in GCS-HS, suggesting that modulation of GCS-LS may play a dominant role in regulating GSH concentration in response to oxidative stress. Additional studies using mitogen-activated protein kinase pathway inhibitors showed that induction by 4HNE of GCS-HS, but not GCS-LS, was mediated through activation of the extracellular regulated kinase pathway in L2 cells. The results demonstrate that L2 cells maintain the same responsiveness to oxidant challenge as do primary cultured AT2 cells in terms of increasing GSH synthetic capacity, and that different pathways are involved in the induction of two GCS subunits by 4HNE.
Collapse
Affiliation(s)
- R M Liu
- Department of Environmental Health Sciences, University of Alabama at Birmingham, School of Public Health, Birmingham, Alabama 35294-0022, USA
| | | | | |
Collapse
|
34
|
Plopper CG, Buckpitt A, Evans M, Van Winkle L, Fanucchi M, Smiley-Jewell S, Lakritz J, West J, Lawson G, Paige R, Miller L, Hyde D. Factors modulating the epithelial response to toxicants in tracheobronchial airways. Toxicology 2001; 160:173-80. [PMID: 11246137 DOI: 10.1016/s0300-483x(00)00453-4] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
As one of the principal interfaces between the organism and the environment, the respiratory system is a target for a wide variety of toxicants and carcinogens. The cellular and architectural complexity of the respiratory system appears to play a major role in defining the focal nature of the pulmonary response to environmental stressors. This review will address the biological factors that modulate the response of one of the major target compartments within the respiratory system, the tracheobronchial airway tree. Individual airway segments respond uniquely to toxic stress and this response involves not only the target cell population, e.g. epithelium, but also other components of the airway wall suggesting a trophic interaction within all components of the airway wall in maintaining steady state and responding to injury. A number of biological factors modulate the nature of the response, including: (1) metabolic potential at specific sites for activation and detoxification; (2) the nature of the local inflammatory response; (3) age of the organism at the time of exposure; (4) gender of the exposed organism; (5) history of previous exposure; and (6) species and strain of the organism exposed.
Collapse
Affiliation(s)
- C G Plopper
- VM: Anatomy, Physiology and Cell Biology, School of Veterinary Medicine, University of California, Davis, CA 95616, USA
| | | | | | | | | | | | | | | | | | | | | | | |
Collapse
|
35
|
Plopper CG, Van Winkle LS, Fanucchi MV, Malburg SR, Nishio SJ, Chang A, Buckpitt AR. Early events in naphthalene-induced acute Clara cell toxicity. II. Comparison of glutathione depletion and histopathology by airway location. Am J Respir Cell Mol Biol 2001; 24:272-81. [PMID: 11245626 DOI: 10.1165/ajrcmb.24.3.4247] [Citation(s) in RCA: 53] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
Abstract
One of the presumed roles of intracellular glutathione (GSH) is the protection of cells from injury by reactive intermediates produced by the metabolism of xenobiotics. To establish whether GSH depletion is a critical step in the initiation of events that lead to cytotoxicity by P450-activated cytotoxicants, naphthalene, a well-defined Clara cell cytotoxicant, was administered to mice (200 mg/kg) by intraperitoneal injection. Shortly after injection (1, 2, and 3 h), intracellular GSH content was assessed by high performance liquid chromatography or quantitative epifluorescent imaging microscopy and compared with the degree of cytotoxicity as assessed by high resolution histopathology. In highly susceptible airways (distal bronchioles), GSH decreased by 50% in 1 h. Cytoplasmic vacuolization was not visible until 2 h, when GSH had decreased by an additional 50%. By 3 h, cytoplasmic blebbing was extensive. In minimally susceptible airways (lobar and proximal bronchi), GSH depletion varied widely within the population; a small proportion of the cells lost greater than 50% of their GSH by 2 h and a significant percentage of the cells retained most of their GSH throughout the entire 3 h. Cytoplasmic vacuolization was apparent in some of the cells at 2 h but not visible in any cells at 3 h. We conclude that (1) loss of intracellular GSH is an early event that precedes initial signs of cellular damage in Clara cell cytotoxicity; (2) this pattern of loss in relation to early injury is found both in highly susceptible and minimally susceptible airway sites; (3) there is wide cell-to-cell heterogeneity in the response; (4) the heterogeneity in the response profile varies between populations in highly susceptible and minimally susceptible sites; and (5) once the intracellular GSH concentration within the entire cell population drops below a certain threshold, the initial phase of injury becomes irreversible.
Collapse
Affiliation(s)
- C G Plopper
- Department of Anatomy, School of Veterinary Medicine, University of California-Davis, Davis 95616, USA.
| | | | | | | | | | | | | |
Collapse
|
36
|
Sterner-Kock A, Kock M, Braun R, Hyde DM. Ozone-induced epithelial injury in the ferret is similar to nonhuman primates. Am J Respir Crit Care Med 2000; 162:1152-6. [PMID: 10988145 DOI: 10.1164/ajrccm.162.3.9812153] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022] Open
Abstract
Extrapolation to humans from rodent ozone exposure is limited by the anatomic differences between the species. Ferrets have similar pulmonary structures to humans, with well developed respiratory bronchioles and submucosal glands. We exposed adult ferrets, monkeys, and rats to 1 ppm ozone (O(3)) or filtered air for 8 h followed by 1 h in filtered air. Bronchoalveolar lavage (BAL) analysis, histopathology, and confocal microscopy were used to evaluate ozone-induced epithelial injury and inflammation. BAL showed significantly increased numbers of neutrophils in ozone-exposed as compared with filtered air ferrets, monkeys, and rats. However, there were 3- to 4-fold more neutrophils in monkeys and ferrets per milliliter of BAL than in rats. Ozone-exposed lungs showed a severe, acute infiltration of neutrophils in regions with necrotic epithelial cells, especially in the centriacinar region that was more severe in ferrets and monkeys than rats. We conclude that acute ozone exposure in ferrets induce severe epithelial necrosis and inflammation, results in similar epithelial injury compared with monkeys, and represents a better model of humans than rodents.
Collapse
Affiliation(s)
- A Sterner-Kock
- Department of Anatomy, Physiology and Cell Biology and California Regional Primate Research Center, University of California, Davis, California, USA
| | | | | | | |
Collapse
|
37
|
Hyde DM, Miller LA, McDonald RJ, Stovall MY, Wong V, Pinkerton KE, Wegner CD, Rothlein R, Plopper CG. Neutrophils enhance clearance of necrotic epithelial cells in ozone-induced lung injury in rhesus monkeys. THE AMERICAN JOURNAL OF PHYSIOLOGY 1999; 277:L1190-8. [PMID: 10600890 DOI: 10.1152/ajplung.1999.277.6.l1190] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
To test the hypothesis that neutrophil influx is important for the removal of necrotic airway epithelial cells, rhesus monkeys were treated with a function-blocking monoclonal antibody (MAb) against CD18 followed by exposure to ozone or filtered air. CD18 MAb-treated, ozone-exposed monkeys showed a significant inhibition of neutrophil emigration and an accumulation of necrotic airway epithelial cells. In a subsequent experiment, monkeys were given CD18 MAb or an isotype control immunoglobulin before ozone or filtered-air exposure. Complement 5a was instilled into lobes of the right lung at the end of the exposure. Lavage neutrophils were significantly elevated in the right lobes compared with those in the contralateral left lobes; consequently, there were significantly fewer necrotic cells in the airways of the right lung, whereas large aggregations of necrotic cells were observed in the contralateral airways of the left lung. These data indicate that neutrophil influx in ozone-induced injury in primates is CD18 dependent and that neutrophils contribute to the repair of airway epithelium by removal of injured epithelial cells.
Collapse
Affiliation(s)
- D M Hyde
- California Regional Primate Research Center and Center for Comparative Respiratory Biology and Medicine, University of California, Davis, California 95616, USA.
| | | | | | | | | | | | | | | | | |
Collapse
|