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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.
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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
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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.
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Affiliation(s)
- Gary E Hatch
- National Health and Environmental Effects Research Laboratory, U.S. Environmental Protection Agency, Research Triangle Park, North Carolina
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Reeser WH, Lee GM, Taylor A, Wang L, Arnold SF, Ultman JS, Ben-Jebria A. Uptake of Ozone in Human Lungs and Its Relationship to Local Physiological Response. Inhal Toxicol 2008; 17:699-707. [PMID: 16195205 DOI: 10.1080/08958370500224433] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
To investigate whether intersubject variations in the dose of inhaled ozone (O(3)) cause corresponding variations in the physiological response, 28 female and 32 male nonsmokers participated in a 1-h continuous inhalation of clean air or 0.25 ppm O(3) while exercising on a cycle ergometer at a constant ventilation rate of 30 L/min. The exposure protocols included continuous monitoring of respiratory flow rate and O(3) concentration from which O(3) uptake (OZU) and fractional uptake efficiency (UE) were computed. Pre-to-post changes in forced expired volume in 1 s (%DeltaFEV(1)), peripheral cross section for carbon dioxide diffusion (%Delta A(P)), and Fowler dead space volume (V(D)) were also measured for each exposure. Individual values of UE ranged from .70 to .98 among all the subjects, with significant differences (p<.05) existing between men and women. These intersubject differences were inversely correlated with breathing frequency and directly correlated with tidal volume. The mean +/- SD values of %Delta FEV(1), %Delta A(P), and %Delta V(D) were all significantly more negative in the O(3) exposure session (-13.31 +/- 13.40, -8.14 +/- 7.62, and -4.20 +/- 5.12, respectively) than in the air exposure session (-0.06 +/- 4.56, 0.22 +/- 10.82, and -0.70 +/- 6.88, respectively). Finally, our results showed that neither %DeltaFEV(1) nor %Delta V(D) was correlated OZU, whereas there was a significant relationship (rho = -0.325, p = .0257) between %Delta A(P) and OZU. We conclude that the overall uptake of O(3) is a weak predictor of intersubject variations in distal airspace response, but is not a predictor of intersubject variations in conducting airway responses.
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Affiliation(s)
- Wade H Reeser
- Department of Chemical Engineering, Pennsylvania State University, University Park, Pennsylvania 16802, USA
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Tsujino I, Kawakami Y, Kaneko A. Comparative Simulation of Gas Transport in Airway Models of Rat, Dog, and Human. Inhal Toxicol 2008; 17:475-85. [PMID: 16020042 DOI: 10.1080/08958370590964476] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Although a number of animal studies have been conducted to investigate the toxic effects of gaseous pollutants on human airways, the anatomical and physiological differences between animals and humans represent a challenge in extrapolating the animal data to humans. The aim of this study was to examine how interspecies anatomical and physiological differences influence the transport of the inhaled gases throughout the airways and alveoli. We designed mathematical airway models of three mammalian species, rats, dogs, and humans, in which interspecies differences in airway dimensions and respiratory patterns were taken into account. We then simulated the bulk flow of three gases (ozone [O(3)], nitrogen dioxide [NO(2)], and sulfur dioxide [SO(2)]) and obtained the intra-airway concentrations of the gases and the amount absorbed using these models. For all three gases, both real-time and mean concentrations in the upper and lower airways were higher in humans when compared with rats and dogs. For example, the mean concentration of O(3) in the 5th bronchi of humans was 3 and 12 times higher than in rats and dogs, respectively. Similarly, the amount of absorbed gases corrected for airway surface area was again higher in the upper and lower airways of humans than the other two species. Sensitivity analysis indicated that tidal volume, respiratory rate, and surface area of the upper and lower airways had significant impact on the results. In conclusion, kinetics of inhaled gaseous substances vary substantially among animals and humans, and such variations are, at least partially, the result of anatomical and physiological differences in their airways.
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Affiliation(s)
- Ichizo Tsujino
- First Department of Medicine, Hokkaido University School of Medicine, Sapporo.
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Alexia J, Lewis CA, Broadley KJ. EFFECTS OF LOW-LEVEL OZONE EXPOSURE ON REACTIVITY AND CONDUCTANCE IN GUINEA PIG AIRWAYS. Inhal Toxicol 2008. [DOI: 10.1080/089583798197808] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/17/2022]
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van Bree L, Marra M, van Scheindelen HJ, Fischer PH, de Loos S, Buringh E, Rombout PJ. Dose-effect models for ozone exposure: tool for quantitative risk estimation. Toxicol Lett 1995; 82-83:317-21. [PMID: 8597071 DOI: 10.1016/0378-4274(95)03484-6] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/31/2023]
Abstract
Short-term ozone exposure causes lung function decrements, increased airway reactivity, airway inflammation, increased respiratory symptoms and hospital admissions. Exposure to long-term elevated ozone levels seems to be associated with reduced lung function (aging), increase of respiratory symptoms, exacerbation of asthma, and airway cell and tissue changes. Health risk caused by exposure to ozone has been evaluated mainly in a qualitative way by comparing ozone air quality data with health-based guidelines or standards. A preliminary approach to quantifying health risk from short-term exposure to oxidant air pollution has been taken by expert judgement, describing known or expected effects at specific levels of ozone. For quantitative assessment of the health impact of distinct ozone exposure conditions (acute, repeated daily, chronic) specific exposure-dose-response models are being developed which can be linked to human exposure data. Exposure-(dose-)response models using data from epidemiological, human-clinical and animal toxicity studies are presented.
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Affiliation(s)
- L van Bree
- National Institute of Public Health and Environment, Bilthoven, The Netherlands
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Abstract
Ozone (O3) is a ubiquitous pollutant with an array of established effects following acute and chronic exposure. Absorption of O3 occurs in all regions of the respiratory tract, but injury to the pulmonary region appears to be of greatest concern because of the susceptibility of this region to the development of chronic disease. Processes that affect the uptake and transport of O3 and available dosimetry models are briefly reviewed prior to discussing recent experimental dosimetry data in laboratory animals and humans. Dosimetry model predictions are compared with experimental data, and an example is provided that illustrates the potential for such models to contribute to our understanding of toxicological results.
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Affiliation(s)
- F J Miller
- Chemical Industry Institute of Toxicology, Research Triangle Park, NC 27709, USA
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Gong H, Linn WS. What we don't understand about ozone effects. Chest 1995; 107:594-5. [PMID: 7874920 DOI: 10.1378/chest.107.3.594] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/27/2023] Open
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