NAM-based prediction of point-of-contact toxicity in the lung: A case example with 1, 3-dichloropropene. (November 2022)

• Record Type: Journal Article
• Authors: Moreau, Marjory; Fisher, Jeff; Andersen, Melvin E.; Barnwell, Asayah; Corzine, Sage; Ranade, Aarati; McMullen, Patrick D.; Slattery, Scott D.
• Is Part Of: Toxicology. Volume 481(2022)
• Publication Date: 2022-11
• Subjects: NAM new approach methodology -- LDH lactate dehydrogenase -- 1, 3-DCP 1, 3-dichloropropene -- 1, 1-DCP 1, 1-dichloropropene -- PoD point of departure -- POC point of contact -- IVIVE in vitro to in vivo extrapolation -- PK pharmacokinetic -- PBPK physiologically based pharmacokinetic (model) -- ALI air–liquid interface -- CFD computational fluid dynamics -- GSH glutathione -- ATP adenosine triphosphate -- EIC equivalent inhaled concentration -- REIC rat equivalent inhaled concentration -- HEIC human equivalent inhaled concentration -- BMD benchmark dose -- BMDL BMD 95% confidence interval lower limit -- BMDU BMD 95% confidence interval upper limit -- URT upper respiratory tract -- MTC mass transfer coefficient -- PC partition coefficient -- CV coefficient of variation -- MC Monte Carlo -- SC sensitivity coefficient; 1, 3-Dichloropropene -- Inhalation -- In vitro -- Vitrocell -- Dosimetry -- PBPK modeling; Toxicology -- Periodicals; Chemicals -- Physiological effect -- Periodicals; 615.9005
• DOI: 10.1016/j.tox.2022.153340
• Languages: English
• ISSNs: 0300-483X

Abstract

Abstract: Time, cost, ethical, and regulatory considerations surrounding in vivo testing methods render them insufficient to meet existing and future chemical safety testing demands. There is a need for the development of in vitro and in silico alternatives to replace traditional in vivo methods for inhalation toxicity assessment. Exposures of differentiated airway epithelial cultures to gases or aerosols at the air–liquid interface (ALI) can assess tissue responses and in vitro to in vivo extrapolation can align in vitro exposure levels with in-life exposures expected to give similar tissue exposures. Because the airway epithelium varies along its length, with various regions composed of different cell types, we have introduced a known toxic vapor to five human-derived, differentiated, in vitro airway epithelial cell culture models—MucilAir of nasal, tracheal, or bronchial origin, SmallAir, and EpiAlveolar—representing five regions of the airway epithelium—nasal, tracheal, bronchial, bronchiolar, and alveolar. We have monitored toxicity in these cultures 24 h after acute exposure using an assay for transepithelial conductance (for epithelial barrier integrity) and the lactate dehydrogenase (LDH) release assay (for cytotoxicity). Our vapor of choice in these experiments was 1, 3-dichloropropene (1, 3-DCP). Finally, we have developed an airway dosimetry model for 1, 3-DCP vapor to predict in vivo external exposure scenarios that would produce toxic local tissue concentrations as determined by in vitro experiments. Measured in vitro points of departure (PoDs) for all tested cell culture models were similar. Calculated rat equivalent inhaled concentrations varied by model according to position of the modeled tissue within the airway, with nasal respiratory tissue being the most proximal and most sensitive tissue, and alveolar epithelium being the most distal and least sensitive tissue. These predictions are qualitatively in accordance with empirically determined in vivo PoDs. The predicted PoD concentrations were close to, but slightly higher than, PoDs determined by in vivo subchronic studies.