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Felkers E, Kluxen FM, Adham S, Vinck AK, Hewitt NJ, Morgan N. Measured air concentrations of pesticides for the estimation of exposure to vapour in European risk assessments. Regul Toxicol Pharmacol 2022; 136:105285. [DOI: 10.1016/j.yrtph.2022.105285] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2022] [Revised: 09/28/2022] [Accepted: 11/04/2022] [Indexed: 11/13/2022]
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Review of air concentrations of pesticides for estimating exposure to vapour in European risk assessments. Regul Toxicol Pharmacol 2022; 132:105172. [DOI: 10.1016/j.yrtph.2022.105172] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/15/2022] [Revised: 03/25/2022] [Accepted: 04/19/2022] [Indexed: 11/22/2022]
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Polak S, Tylutki Z, Holbrook M, Wiśniowska B. Better prediction of the local concentration-effect relationship: the role of physiologically based pharmacokinetics and quantitative systems pharmacology and toxicology in the evolution of model-informed drug discovery and development. Drug Discov Today 2019; 24:1344-1354. [PMID: 31132414 DOI: 10.1016/j.drudis.2019.05.016] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/30/2018] [Revised: 03/04/2019] [Accepted: 05/21/2019] [Indexed: 12/15/2022]
Abstract
Model-informed drug discovery and development (MID3) is an umbrella term under which sit several computational approaches: quantitative systems pharmacology (QSP), quantitative systems toxicology (QST) and physiologically based pharmacokinetics (PBPK). QSP models are built using mechanistic knowledge of the pharmacological pathway focusing on the putative mechanism of drug efficacy; whereas QST models focus on safety and toxicity issues and the molecular pathways and networks that drive these adverse effects. These can be mediated through exaggerated on-target or off-target pharmacology, immunogenicity or the physiochemical nature of the compound. PBPK models provide a mechanistic description of individual organs and tissues to allow the prediction of the intra- and extra-cellular concentration of the parent drug and metabolites under different conditions. Information on biophase concentration enables the prediction of a drug effect in different organs and assessment of the potential for drug-drug interactions. Together, these modelling approaches can inform the exposure-response relationship and hence support hypothesis generation and testing, compound selection, hazard identification and risk assessment through to clinical proof of concept (POC) and beyond to the market.
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Affiliation(s)
- Sebastian Polak
- Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9 Street, 30-688 Kraków, Poland; Certara-Simcyp, Level 2-Acero, 1 Concourse Way, Sheffield, S1 2BJ, UK.
| | - Zofia Tylutki
- Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9 Street, 30-688 Kraków, Poland; Certara-Simcyp, Level 2-Acero, 1 Concourse Way, Sheffield, S1 2BJ, UK
| | - Mark Holbrook
- Certara-Simcyp, Level 2-Acero, 1 Concourse Way, Sheffield, S1 2BJ, UK
| | - Barbara Wiśniowska
- Faculty of Pharmacy, Jagiellonian University Medical College, Medyczna 9 Street, 30-688 Kraków, Poland
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McGraw MD, Veress LA. Reply to: Comment on "Bronchiolitis Obliterans and Pulmonary Fibrosis after Sulfur Mustard Inhalation in Rats". Am J Respir Cell Mol Biol 2018; 59:274-275. [PMID: 30067093 DOI: 10.1165/rcmb.2018-0119le] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/24/2022] Open
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Clippinger AJ, Allen D, Jarabek AM, Corvaro M, Gaça M, Gehen S, Hotchkiss JA, Patlewicz G, Melbourne J, Hinderliter P, Yoon M, Huh D, Lowit A, Buckley B, Bartels M, BéruBé K, Wilson DM, Indans I, Vinken M. Alternative approaches for acute inhalation toxicity testing to address global regulatory and non-regulatory data requirements: An international workshop report. Toxicol In Vitro 2017; 48:53-70. [PMID: 29277654 DOI: 10.1016/j.tiv.2017.12.011] [Citation(s) in RCA: 50] [Impact Index Per Article: 7.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/05/2017] [Revised: 12/11/2017] [Accepted: 12/14/2017] [Indexed: 12/15/2022]
Abstract
Inhalation toxicity testing, which provides the basis for hazard labeling and risk management of chemicals with potential exposure to the respiratory tract, has traditionally been conducted using animals. Significant research efforts have been directed at the development of mechanistically based, non-animal testing approaches that hold promise to provide human-relevant data and an enhanced understanding of toxicity mechanisms. A September 2016 workshop, "Alternative Approaches for Acute Inhalation Toxicity Testing to Address Global Regulatory and Non-Regulatory Data Requirements", explored current testing requirements and ongoing efforts to achieve global regulatory acceptance for non-animal testing approaches. The importance of using integrated approaches that combine existing data with in vitro and/or computational approaches to generate new data was discussed. Approaches were also proposed to develop a strategy for identifying and overcoming obstacles to replacing animal tests. Attendees noted the importance of dosimetry considerations and of understanding mechanisms of acute toxicity, which could be facilitated by the development of adverse outcome pathways. Recommendations were made to (1) develop a database of existing acute inhalation toxicity data; (2) prepare a state-of-the-science review of dosimetry determinants, mechanisms of toxicity, and existing approaches to assess acute inhalation toxicity; (3) identify and optimize in silico models; and (4) develop a decision tree/testing strategy, considering physicochemical properties and dosimetry, and conduct proof-of-concept testing. Working groups have been established to implement these recommendations.
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Affiliation(s)
| | - David Allen
- Integrated Laboratory Systems, contractor supporting the NTP Interagency Center for the Evaluation of Alternative Toxicological Methods, Research Triangle Park, NC, United States
| | - Annie M Jarabek
- U.S. Environmental Protection Agency, Office of Research and Development, National Center for Environmental Assessment, Research Triangle Park, NC, United States
| | | | | | - Sean Gehen
- Dow AgroSciences, Indianapolis, IN, United States
| | | | - Grace Patlewicz
- U.S. Environmental Protection Agency, Office of Research and Development, National Center for Computational Toxicology, Research Triangle Park, NC, United States
| | | | | | - Miyoung Yoon
- Scitovation LLC, Research Triangle Park, NC, United States
| | - Dongeun Huh
- University of Pennsylvania, Philadelphia, PA, United States
| | - Anna Lowit
- U.S. Environmental Protection Agency, Office of Chemical Safety and Pollution Prevention, Office of Pesticide Programs, Washington, DC, United States
| | - Barbara Buckley
- U.S. Environmental Protection Agency, Office of Research and Development, National Center for Environmental Assessment, Research Triangle Park, NC, United States
| | | | - Kelly BéruBé
- Cardiff University, School of Biosciences, Cardiff, Wales, UK
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Cichocki JA, Morris JB. Inhalation dosimetry modeling provides insights into regional respiratory tract toxicity of inhaled diacetyl. Toxicology 2016; 388:30-39. [PMID: 27851905 DOI: 10.1016/j.tox.2016.11.007] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2016] [Revised: 11/04/2016] [Accepted: 11/07/2016] [Indexed: 11/15/2022]
Abstract
Vapor dosimetry models provide a means of assessing the role of delivered dose in determining the regional airway response to inspired vapors. A validated hybrid computational fluid dynamics physiologically based pharmacokinetic model for inhaled diacetyl has been developed to describe inhaled diacetyl dosimetry in both the rat and human respiratory tracts. Comparison of the distribution of respiratory tract injury with dosimetry estimates provides strong evidence that regional delivered dose rather than regional airway tissue sensitivity to diacetyl-induced injury is the critical determinant of the regional respiratory tract response to this water soluble reactive vapor. In the rat, inhalation exposure to diacetyl causes much lesser injury in the distal bronchiolar airways compared to nose and large tracheobronchial airways. The degree of injury correlates very strongly to model based estimates of local airway diacetyl concentrations. According to the model, regional dosimetry patterns of diacetyl in the human differ greatly from those in the rat with much greater penetration of diacetyl to the bronchiolar airways in the lightly exercising mouth breathing human compared to the rat, providing evidence that rat inhalation toxicity studies underpredict the risk of bronchiolar injury in the human. For example, repeated exposure of the rat to 200ppm diacetyl results in bronchiolar injury; the estimated bronchiolar tissue concentration in rats exposed to 200ppm diacetyl would occur in lightly exercising mouth breathing humans exposed to 12ppm. Consideration of airway dosimetry patterns of inspired diacetyl is critical to the proper evaluation of rodent toxicity data and its relevance for predicting human risk.
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Affiliation(s)
- Joseph A Cichocki
- Department of Veterinary Integrative Biosciences, College of Veterinary Medicine and Biomedical Sciences, Texas A&M University, College Station, TX, United States
| | - John B Morris
- Toxicology Program, Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, 69 N. Eagleville Road, Storrs, CT 06269, United States.
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Smith GJ, Cichocki JA, Doughty BJ, Manautou JE, Jordt SE, Morris JB. Effects of Acetaminophen on Oxidant and Irritant Respiratory Tract Responses to Environmental Tobacco Smoke in Female Mice. ENVIRONMENTAL HEALTH PERSPECTIVES 2016; 124:642-50. [PMID: 26452297 PMCID: PMC4858387 DOI: 10.1289/ehp.1509851] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 02/18/2015] [Accepted: 10/05/2015] [Indexed: 06/05/2023]
Abstract
BACKGROUND Although it is known that acetaminophen causes oxidative injury in the liver, it is not known whether it causes oxidative stress in the respiratory tract. If so, this widely used analgesic may potentiate the adverse effects of oxidant air pollutants. OBJECTIVES The goal of this study was to determine if acetaminophen induces respiratory tract oxidative stress and/or potentiates the oxidative stress and irritant responses to an inhaled oxidant: environmental tobacco smoke (ETS). METHODS Acetaminophen [100 mg/kg intraperitoneal (ip)] and/or sidestream tobacco smoke (as a surrogate for ETS, 5 mg/m3 for 10 min) were administered to female C57Bl/6J mice, and airway oxidative stress was assessed by loss of tissue antioxidants [estimated by nonprotein sulfhydryl (NPSH) levels] and/or induction of oxidant stress response genes. In addition, the effects of acetaminophen on airway irritation reflex responses to ETS were examined by plethysmography. RESULTS Acetaminophen diminished NPSH in nasal, thoracic extrapulmonary, and lung tissues; it also induced the oxidant stress response genes glutamate-cysteine ligase, catalytic subunit, and NAD(P)H dehydrogenase, quinone 1, in these sites. ETS produced a similar response. The response to acetaminophen plus ETS was equal to or greater than the sum of the responses to either agent alone. Although it had no effect by itself, acetaminophen greatly increased the reflex irritant response to ETS. CONCLUSIONS At supratherapeutic levels, acetaminophen induced oxidative stress throughout the respiratory tract and appeared to potentiate some responses to environmentally relevant ETS exposure in female C57Bl/6J mice. These results highlight the potential for this widely used drug to modulate responsiveness to oxidant air pollutants. CITATION Smith GJ, Cichocki JA, Doughty BJ, Manautou JE, Jordt SE, Morris JB. 2016. Effects of acetaminophen on oxidant and irritant respiratory tract responses to environmental tobacco smoke in female mice. Environ Health Perspect 124:642-650; http://dx.doi.org/10.1289/ehp.1509851.
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Affiliation(s)
- Gregory J. Smith
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, Connecticut, USA
| | - Joseph A. Cichocki
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, Connecticut, USA
| | - Bennett J. Doughty
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, Connecticut, USA
| | - Jose E. Manautou
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, Connecticut, USA
| | - Sven-Eric Jordt
- Department of Anesthesiology, Duke University School of Medicine, Durham, North Carolina, USA
| | - John B. Morris
- Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, Storrs, Connecticut, USA
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Zaccone EJ, Goldsmith WT, Shimko MJ, Wells JR, Schwegler-Berry D, Willard PA, Case SL, Thompson JA, Fedan JS. Diacetyl and 2,3-pentanedione exposure of human cultured airway epithelial cells: Ion transport effects and metabolism of butter flavoring agents. Toxicol Appl Pharmacol 2015; 289:542-9. [PMID: 26454031 DOI: 10.1016/j.taap.2015.10.004] [Citation(s) in RCA: 37] [Impact Index Per Article: 4.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/20/2014] [Revised: 09/04/2015] [Accepted: 10/06/2015] [Indexed: 11/29/2022]
Abstract
Inhalation of butter flavoring by workers in the microwave popcorn industry may result in “popcorn workers' lung.” In previous in vivo studies rats exposed for 6 h to vapor from the flavoring agents, diacetyl and 2,3-pentanedione, acquired flavoring concentration-dependent damage of the upper airway epithelium and airway hyporeactivity to inhaled methacholine. Because ion transport is essential for lung fluid balance,we hypothesized that alterations in ion transport may be an early manifestation of butter flavoring-induced toxicity.We developed a system to expose cultured human bronchial/tracheal epithelial cells (NHBEs) to flavoring vapors. NHBEs were exposed for 6 h to diacetyl or 2,3-pentanedione vapors (25 or ≥ 60 ppm) and the effects on short circuit current and transepithelial resistance (Rt) were measured. Immediately after exposure to 25 ppm both flavorings reduced Na+ transport,without affecting Cl- transport or Na+,K+-pump activity. Rt was unaffected. Na+ transport recovered 18 h after exposure. Concentrations (100-360 ppm) of diacetyl and 2,3-pentanedione reported earlier to give rise in vivo to epithelial damage, and 60 ppm, caused death of NHBEs 0 h post-exposure. Analysis of the basolateral medium indicated that NHBEs metabolize diacetyl and 2,3-pentanedione to acetoin and 2-hydroxy-3-pentanone, respectively. The results indicate that ion transport is inhibited transiently in airway epithelial cells by lower concentrations of the flavorings than those that result in morphological changes of the cells in vivo or in vitro.
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Affiliation(s)
- Eric J Zaccone
- Department of Pharmaceutical Sciences, West Virginia University, Morgantown, WV, USA
| | - W Travis Goldsmith
- Pathology and Physiology Research Branch, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Michael J Shimko
- Department of Pharmaceutical Sciences, West Virginia University, Morgantown, WV, USA
| | - J R Wells
- Pathology and Physiology Research Branch, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Diane Schwegler-Berry
- Pathology and Physiology Research Branch, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Patsy A Willard
- Pathology and Physiology Research Branch, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Shannon L Case
- Pathology and Physiology Research Branch, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Janet A Thompson
- Pathology and Physiology Research Branch, National Institute for Occupational Safety and Health, Morgantown, WV, USA
| | - Jeffrey S Fedan
- Department of Pharmaceutical Sciences, West Virginia University, Morgantown, WV, USA; Pathology and Physiology Research Branch, National Institute for Occupational Safety and Health, Morgantown, WV, USA
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Gaohua L, Wedagedera J, Small BG, Almond L, Romero K, Hermann D, Hanna D, Jamei M, Gardner I. Development of a Multicompartment Permeability-Limited Lung PBPK Model and Its Application in Predicting Pulmonary Pharmacokinetics of Antituberculosis Drugs. CPT-PHARMACOMETRICS & SYSTEMS PHARMACOLOGY 2015; 4:605-13. [PMID: 26535161 PMCID: PMC4625865 DOI: 10.1002/psp4.12034] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/17/2015] [Accepted: 08/18/2015] [Indexed: 12/20/2022]
Abstract
Achieving sufficient concentrations of antituberculosis (TB) drugs in pulmonary tissue at the optimum time is still a challenge in developing therapeutic regimens for TB. A physiologically based pharmacokinetic model incorporating a multicompartment permeability-limited lung model was developed and used to simulate plasma and pulmonary concentrations of seven drugs. Passive permeability of drugs within the lung was predicted using an in vitro-in vivo extrapolation approach. Simulated epithelial lining fluid (ELF):plasma concentration ratios showed reasonable agreement with observed clinical data for rifampicin, isoniazid, ethambutol, and erythromycin. For clarithromycin, itraconazole and pyrazinamide the observed ELF:plasma ratios were significantly underpredicted. Sensitivity analyses showed that changing ELF pH or introducing efflux transporter activity between lung tissue and ELF can alter the ELF:plasma concentration ratios. The described model has shown utility in predicting the lung pharmacokinetics of anti-TB drugs and provides a framework for predicting pulmonary concentrations of novel anti-TB drugs.
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Affiliation(s)
- L Gaohua
- Simcyp Limited (a Certara company) Sheffield, United Kingdom
| | - J Wedagedera
- Simcyp Limited (a Certara company) Sheffield, United Kingdom
| | - B G Small
- Simcyp Limited (a Certara company) Sheffield, United Kingdom
| | - L Almond
- Simcyp Limited (a Certara company) Sheffield, United Kingdom
| | - K Romero
- Critical Path Institute Tucson, Arizona, USA
| | - D Hermann
- Certara USA, Inc. Princeton, New Jersey, USA
| | - D Hanna
- Critical Path Institute Tucson, Arizona, USA
| | - M Jamei
- Simcyp Limited (a Certara company) Sheffield, United Kingdom
| | - I Gardner
- Simcyp Limited (a Certara company) Sheffield, United Kingdom
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Borghardt JM, Weber B, Staab A, Kloft C. Pharmacometric Models for Characterizing the Pharmacokinetics of Orally Inhaled Drugs. AAPS J 2015; 17:853-70. [PMID: 25845315 PMCID: PMC4477002 DOI: 10.1208/s12248-015-9760-6] [Citation(s) in RCA: 59] [Impact Index Per Article: 6.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/17/2014] [Accepted: 03/25/2015] [Indexed: 12/12/2022] Open
Abstract
During the last decades, the importance of modeling and simulation in clinical drug development, with the goal to qualitatively and quantitatively assess and understand mechanisms of pharmacokinetic processes, has strongly increased. However, this increase could not equally be observed for orally inhaled drugs. The objectives of this review are to understand the reasons for this gap and to demonstrate the opportunities that mathematical modeling of pharmacokinetics of orally inhaled drugs offers. To achieve these objectives, this review (i) discusses pulmonary physiological processes and their impact on the pharmacokinetics after drug inhalation, (ii) provides a comprehensive overview of published pharmacokinetic models, (iii) categorizes these models into physiologically based pharmacokinetic (PBPK) and (clinical data-derived) empirical models, (iv) explores both their (mechanistic) plausibility, and (v) addresses critical aspects of different pharmacometric approaches pertinent for drug inhalation. In summary, pulmonary deposition, dissolution, and absorption are highly complex processes and may represent the major challenge for modeling and simulation of PK after oral drug inhalation. Challenges in relating systemic pharmacokinetics with pulmonary efficacy may be another factor contributing to the limited number of existing pharmacokinetic models for orally inhaled drugs. Investigations comprising in vitro experiments, clinical studies, and more sophisticated mathematical approaches are considered to be necessary for elucidating these highly complex pulmonary processes. With this additional knowledge, the PBPK approach might gain additional attractiveness. Currently, (semi-)mechanistic modeling offers an alternative to generate and investigate hypotheses and to more mechanistically understand the pulmonary and systemic pharmacokinetics after oral drug inhalation including the impact of pulmonary diseases.
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Affiliation(s)
- Jens Markus Borghardt
- />Department of Clinical Pharmacy and Biochemistry, Institute of Pharmacy, Freie Universitaet Berlin, Kelchstr. 31, 12169 Berlin, Germany
| | - Benjamin Weber
- />Department of Translational Medicine and Clinical Pharmacology, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | - Alexander Staab
- />Department of Translational Medicine and Clinical Pharmacology, Boehringer Ingelheim Pharma GmbH & Co. KG, Biberach, Germany
| | - Charlotte Kloft
- />Department of Clinical Pharmacy and Biochemistry, Institute of Pharmacy, Freie Universitaet Berlin, Kelchstr. 31, 12169 Berlin, Germany
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Kuempel ED, Sweeney LM, Morris JB, Jarabek AM. Advances in Inhalation Dosimetry Models and Methods for Occupational Risk Assessment and Exposure Limit Derivation. JOURNAL OF OCCUPATIONAL AND ENVIRONMENTAL HYGIENE 2015; 12 Suppl 1:S18-40. [PMID: 26551218 PMCID: PMC4685615 DOI: 10.1080/15459624.2015.1060328] [Citation(s) in RCA: 57] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/26/2023]
Abstract
The purpose of this article is to provide an overview and practical guide to occupational health professionals concerning the derivation and use of dose estimates in risk assessment for development of occupational exposure limits (OELs) for inhaled substances. Dosimetry is the study and practice of measuring or estimating the internal dose of a substance in individuals or a population. Dosimetry thus provides an essential link to understanding the relationship between an external exposure and a biological response. Use of dosimetry principles and tools can improve the accuracy of risk assessment, and reduce the uncertainty, by providing reliable estimates of the internal dose at the target tissue. This is accomplished through specific measurement data or predictive models, when available, or the use of basic dosimetry principles for broad classes of materials. Accurate dose estimation is essential not only for dose-response assessment, but also for interspecies extrapolation and for risk characterization at given exposures. Inhalation dosimetry is the focus of this paper since it is a major route of exposure in the workplace. Practical examples of dose estimation and OEL derivation are provided for inhaled gases and particulates.
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Affiliation(s)
- Eileen D. Kuempel
- National Institute for Occupational Safety and Health, Education and Information Division, Cincinnati, Ohio
| | - Lisa M. Sweeney
- Henry M. Jackson Foundation for the Advancement of Military Medicine, Naval Medical Research Unit Dayton, Wright-Patterson Air Force Base, Ohio
| | - John B. Morris
- School of Pharmacy, University of Connecticut, Storrs, Connecticut
| | - Annie M. Jarabek
- U.S. Environmental Protection Agency, National Center for Environmental Assessment, Research Triangle Park, North Carolina
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Cichocki JA, Smith GJ, Morris JB. Tissue sensitivity of the rat upper and lower extrapulmonary airways to the inhaled electrophilic air pollutants diacetyl and acrolein. Toxicol Sci 2014; 142:126-36. [PMID: 25145656 DOI: 10.1093/toxsci/kfu165] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
Abstract
The target site for inhaled vapor-induced injury often differs in mouth-breathing humans compared with nose-breathing rats, thus complicating the use of rat inhalation toxicity data for assessment of human risk. We sought to examine sensitivity of respiratory/transitional nasal (RTM) and tracheobronchial (TBM) mucosa to two electrophilic irritant vapors: diacetyl and acrolein. Computational fluid dynamic physiologically based pharmacokinetic modeling was coupled with biomarker assessment to establish delivered dose-response relationships in RTM and TBM in male F344 rats following 6 h exposure to diacetyl or acrolein. Biomarkers included glutathione status, proinflammatory and antioxidant gene mRNA levels, and nuclear translocation of nuclear factor (erythroid-derived 2)-like 2 (Nrf2). Modeling revealed that 0.0094-0.1653 μg acrolein/min-cm(2) and 3.9-21.6 μg diacetyl/min-cm(2) were deposited into RTM/TBM. Results indicate RTM and TBM were generally of similar sensitivity to diacetyl and acrolein. For instance, both tissues displayed induction of antioxidant and proinflammatory genes, and nuclear accumulation of Nrf2 after electrophile exposure. Hierarchical cellular response patterns were similar in RTM and TBM but differed between vapors. Specifically, diacetyl exposure induced proinflammatory and antioxidant genes concomitantly at low exposure levels, whereas acrolein induced antioxidant genes at much lower exposure levels than that required to induce proinflammatory genes. Generally, diacetyl was less potent than acrolein, as measured by maximal induction of transcripts. In conclusion, the upper and lower extrapulmonary airways are of similar sensitivity to inhaled electrophilic vapors. Dosimetrically based extrapolation of nasal responses in nose-breathing rodents may provide an approach to predict risk to the lower airways of humans during mouth-breathing.
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Affiliation(s)
- Joseph A Cichocki
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut 06269
| | - Gregory J Smith
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut 06269
| | - John B Morris
- Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut 06269
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Morris JB, Cichocki JA, Smith GJ. In situ measurement of vapor uptake in the rodent upper respiratory tract. ACTA ACUST UNITED AC 2013; Chapter 24:Unit 24.1. [PMID: 23408196 DOI: 10.1002/0471140856.tx2401s55] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
The response of respiratory tract tissue target sites to inhaled vapors depends on the amount of inhaled vapor that is delivered to those sites. Direct measurement of vapor absorption within a specific airway of the living animal requires that the airway be isolated, which currently can only be performed on the upper airways. Towards this end, the upper respiratory tract (all airways anterior to the larynx) is surgically isolated in the anesthetized rat by tracheostomy and insertion of two endotracheal tubes, one leading anteriorly and the other posteriorly. The surgically manipulated animal is then placed in a nose-only inhalation chamber and test-vapor-laden air is drawn through the isolated upper airways under defined air flow conditions via the anterior endotracheal tube. The animal spontaneously respires clean air into the lungs during this procedure via the posterior endotracheal tube. The concentration of test vapor in air entering and the air exiting the upper airways is measured by gas chromatography, and the difference in concentrations provides a measure of vapor absorption in that site. A rich database is available on upper respiratory tract vapor absorption as measured by this methodology, to which newly obtained data can be compared. These data have been instrumental not only in understanding the regional airway toxicity of inspired vapors, but also for developing mathematical models to describe inhaled vapor dosimetry.
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Affiliation(s)
- John B Morris
- Toxicology Program, Department of Pharmaceutical Sciences, University of Connecticut, Storrs, Connecticut, USA
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Goravanahally MP, Hubbs AF, Fedan JS, Kashon ML, Battelli LA, Mercer RR, Goldsmith WT, Jackson MC, Cumpston A, Frazer DG, Dey RD. Diacetyl increases sensory innervation and substance P production in rat trachea. Toxicol Pathol 2013; 42:582-90. [PMID: 23847039 DOI: 10.1177/0192623313493689] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Inhalation of diacetyl, a butter flavoring, causes airway responses potentially mediated by sensory nerves. This study examines diacetyl-induced changes in sensory nerves of tracheal epithelium. Rats (n = 6/group) inhaled 0-, 25-, 249-, or 346-ppm diacetyl for 6 hr. Tracheas and vagal ganglia were removed 1-day postexposure and labeled for substance P (SP) or protein gene product 9.5 (PGP9.5). Vagal ganglia neurons projecting to airway epithelium were identified by axonal transport of fluorescent microspheres intratracheally instilled 14 days before diacetyl inhalation. End points were SP and PGP9.5 nerve fiber density (NFD) in tracheal epithelium and SP-positive neurons projecting to the trachea. PGP9.5-immunoreactive NFD decreased in foci with denuded epithelium, suggesting loss of airway sensory innervation. However, in the intact epithelium adjacent to denuded foci, SP-immunoreactive NFD increased from 0.01 ± 0.002 in controls to 0.05 ± 0.01 after exposure to 346-ppm diacetyl. In vagal ganglia, SP-positive airway neurons increased from 3.3 ± 3.0% in controls to 25.5 ± 6.6% after inhaling 346-ppm diacetyl. Thus, diacetyl inhalation increases SP levels in sensory nerves of airway epithelium. Because SP release in airways promotes inflammation and activation of sensory nerves mediates reflexes, neural changes may contribute to flavorings-related lung disease pathogenesis.
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Affiliation(s)
- Madhusudan P Goravanahally
- 1Health Effects Laboratory Division, National Institute for Occupational Safety and Health, Morgantown, West Virginia, USA
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Morris JB. Nasal dosimetry of inspired naphthalene vapor in the male and female B6C3F1 mouse. Toxicology 2013; 309:66-72. [PMID: 23619605 DOI: 10.1016/j.tox.2013.04.009] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2012] [Revised: 03/28/2013] [Accepted: 04/12/2013] [Indexed: 11/29/2022]
Abstract
Naphthalene vapor is a nasal cytotoxicant in the rat and mouse but is a nasal carcinogen in only the rat. Inhalation dosimetry is a critical aspect of the inhalation toxicology of inspired vapors and may contribute to the species differences in the nasal response. To define the nasal dosimetry of naphthalene in the B6C3F1 male and female mouse, uptake of naphthalene vapor was measured in the surgically isolated upper respiratory tract (URT) at inspiratory flow rates of 25 or 50 ml/min. Uptake was measured at multiple concentrations (0.5, 3, 10, 30 ppm) in controls and mice treated with the cytochrome P450 inhibitor 5-phenyl-1-pentyne. In both sexes, URT uptake efficiency was strongly concentration dependent averaging 90% at 0.5 ppm compared to 50% at 30 ppm (25 ml/min flow rate), indicating saturable processes were involved. Both uptake efficiency and the concentration dependence of uptake were significantly diminished by 5-phenyl-1-pentyne indicating inspired naphthalene vapor is extensively metabolized in the mouse nose with saturation of metabolism occurring at the higher concentrations. A hybrid computational fluid dynamic physiologically based pharmacokinetic model was developed for nasal dosimetry. This model accurately predicted the observed URT uptake efficiencies. Overall, the high URT uptake efficiency of naphthalene in the mouse nose indicates the absence of a tumorigenic response is not attributable to low delivered dose rates in this species.
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Affiliation(s)
- John B Morris
- Toxicology Program, Department of Pharmaceutical Sciences, School of Pharmacy, University of Connecticut, 69 N. Eagleville Road, Storrs, CT 06269, USA.
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Buckpitt A, Morin D, Murphy S, Edwards P, Van Winkle L. Kinetics of naphthalene metabolism in target and non-target tissues of rodents and in nasal and airway microsomes from the Rhesus monkey. Toxicol Appl Pharmacol 2013; 270:97-105. [PMID: 23602890 DOI: 10.1016/j.taap.2013.04.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/31/2012] [Revised: 03/29/2013] [Accepted: 04/11/2013] [Indexed: 01/09/2023]
Abstract
Naphthalene produces species and cell selective injury to respiratory tract epithelial cells of rodents. In these studies we determined the apparent Km, Vmax, and catalytic efficiency (Vmax/Km) for naphthalene metabolism in microsomal preparations from subcompartments of the respiratory tract of rodents and non-human primates. In tissues with high substrate turnover, major metabolites were derived directly from naphthalene oxide with smaller amounts from conjugates of diol epoxide, diepoxide, and 1,2- and 1,4-naphthoquinones. In some tissues, different enzymes with dissimilar Km and Vmax appeared to metabolize naphthalene. The rank order of Vmax (rat olfactory epithelium>mouse olfactory epithelium>murine airways>>rat airways) correlated well with tissue susceptibility to naphthalene. The Vmax in monkey alveolar subcompartment was 2% that in rat nasal olfactory epithelium. Rates of metabolism in nasal compartments of the monkey were low. The catalytic efficiencies of microsomes from known susceptible tissues/subcompartments are 10 and 250 fold higher than in rat airway and monkey alveolar subcompartments, respectively. Although the strong correlations between catalytic efficiencies and tissue susceptibility suggest that non-human primate tissues are unlikely to generate metabolites at a rate sufficient to produce cellular injury, other studies showing high levels of formation of protein adducts support the need for additional studies.
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Affiliation(s)
- Alan Buckpitt
- Department of Molecular Biosciences, School of Veterinary Medicine, UC Davis, Davis, CA 95616, USA.
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Zaccone EJ, Thompson JA, Ponnoth DS, Cumpston AM, Goldsmith WT, Jackson MC, Kashon ML, Frazer DG, Hubbs AF, Shimko MJ, Fedan JS. Popcorn flavoring effects on reactivity of rat airways in vivo and in vitro. JOURNAL OF TOXICOLOGY AND ENVIRONMENTAL HEALTH. PART A 2013; 76:669-689. [PMID: 23941636 PMCID: PMC4499850 DOI: 10.1080/15287394.2013.796302] [Citation(s) in RCA: 16] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/30/2023]
Abstract
"Popcorn workers' lung" is an obstructive pulmonary disease produced by inhalation of volatile artificial butter flavorings. In rats, inhalation of diacetyl, a major component of butter flavoring, and inhalation of a diacetyl substitute, 2,3-pentanedione, produce similar damage to airway epithelium. The effects of diacetyl and 2,3-pentanedione and mixtures of diacetyl, acetic acid, and acetoin, all components of butter flavoring, on pulmonary function and airway reactivity to methacholine (MCh) were investigated. Lung resistance (RL) and dynamic compliance (Cdyn) were negligibly changed 18 h after a 6-h inhalation exposure to diacetyl or 2,3-pentanedione (100-360 ppm). Reactivity to MCh was not markedly changed after diacetyl, but was modestly decreased after 2,3-pentanedione inhalation. Inhaled diacetyl exerted essentially no effect on reactivity to mucosally applied MCh, but 2,3-pentanedione (320 and 360 ppm) increased reactivity to MCh in the isolated, perfused trachea preparation (IPT). In IPT, diacetyl and 2,3-pentanedione (≥3 mM) applied to the serosal and mucosal surfaces of intact and epithelium-denuded tracheas initiated transient contractions followed by relaxations. Inhaled acetoin (150 ppm) exerted no effect on pulmonary function and airway reactivity in vivo; acetic acid (27 ppm) produced hyperreactivity to MCh; and exposure to diacetyl + acetoin + acetic acid (250 + 150 + 27 ppm) led to a diacetyl-like reduction in reactivity. Data suggest that the effects of 2,3-pentanedione on airway reactivity are greater than those of diacetyl, and that flavorings are airway smooth muscle relaxants and constrictors, thus indicating a complex mechanism.
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Affiliation(s)
- Eric J. Zaccone
- Department of Basic Pharmaceutical Sciences, West Virginia University, Morgantown, West Virginia, USA
| | - Janet A. Thompson
- Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, West Virginia, USA
| | - Dovenia S. Ponnoth
- Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, West Virginia, USA
| | - Amy M. Cumpston
- Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, West Virginia, USA
| | - W. Travis Goldsmith
- Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, West Virginia, USA
| | - Mark C. Jackson
- Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, West Virginia, USA
| | - Michael L. Kashon
- Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, West Virginia, USA
| | - David G. Frazer
- Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, West Virginia, USA
| | - Ann F. Hubbs
- Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, West Virginia, USA
| | - Michael J. Shimko
- Department of Basic Pharmaceutical Sciences, West Virginia University, Morgantown, West Virginia, USA
| | - Jeffrey S. Fedan
- Centers for Disease Control and Prevention, National Institute for Occupational Safety and Health, Morgantown, West Virginia, USA
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