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Villeneuve DL, Blackwell BR, Blanksma CA, Cavallin JE, Cheng WY, Conolly RB, Conrow K, Feifarek DJ, Heinis LJ, Jensen KM, Kahl MD, Milsk RY, Poole ST, Randolph EC, Saari TW, Watanabe KH, Ankley GT. Case Study in 21st-Century Ecotoxicology: Using In Vitro Aromatase Inhibition Data to Predict Reproductive Outcomes in Fish In Vivo. Environ Toxicol Chem 2023; 42:100-116. [PMID: 36282016 PMCID: PMC10782516 DOI: 10.1002/etc.5504] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/29/2022] [Revised: 06/24/2022] [Accepted: 10/18/2022] [Indexed: 06/16/2023]
Abstract
To reduce the use of intact animals for chemical safety testing, while ensuring protection of ecosystems and human health, there is a demand for new approach methodologies (NAMs) that provide relevant scientific information at a quality equivalent to or better than traditional approaches. The present case study examined whether bioactivity and associated potency measured in an in vitro screening assay for aromatase inhibition could be used together with an adverse outcome pathway (AOP) and mechanistically based computational models to predict previously uncharacterized in vivo effects. Model simulations were used to inform designs of 60-h and 10-21-day in vivo exposures of adult fathead minnows (Pimephales promelas) to three or four test concentrations of the in vitro aromatase inhibitor imazalil ranging from 0.12 to 260 µg/L water. Consistent with an AOP linking aromatase inhibition to reproductive impairment in fish, exposure to the fungicide resulted in significant reductions in ex vivo production of 17β-estradiol (E2) by ovary tissue (≥165 µg imazalil/L), plasma E2 concentrations (≥74 µg imazalil/L), vitellogenin (Vtg) messenger RNA expression (≥165 µg imazalil/L), Vtg plasma concentrations (≥74 µg imazalil/L), uptake of Vtg into oocytes (≥260 µg imazalil/L), and overall reproductive output in terms of cumulative fecundity, number of spawning events, and eggs per spawning event (≥24 µg imazalil/L). Despite many potential sources of uncertainty in potency and efficacy estimates based on model simulations, observed magnitudes of apical effects were quite consistent with model predictions, and in vivo potency was within an order of magnitude of that predicted based on in vitro relative potency. Overall, our study suggests that NAMs and AOP-based approaches can support meaningful reduction and refinement of animal testing. Environ Toxicol Chem 2023;42:100-116. © 2022 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.
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Affiliation(s)
- Daniel L. Villeneuve
- US Environmental Protection Agency, Great Lakes Toxicology and Ecology Division, Duluth, MN, USA
| | - Brett R. Blackwell
- US Environmental Protection Agency, Great Lakes Toxicology and Ecology Division, Duluth, MN, USA
| | | | - Jenna E. Cavallin
- US Environmental Protection Agency, Great Lakes Toxicology and Ecology Division, Duluth, MN, USA
| | - Wan-Yun Cheng
- US Environmental Protection Agency, Integrated Systems Toxicology Division, Research Triangle Park, NC, USA
| | - Rory B. Conolly
- US Environmental Protection Agency, Integrated Systems Toxicology Division, Research Triangle Park, NC, USA
| | - Kendra Conrow
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ 85306-4908
| | - David J. Feifarek
- Student Services Contractor, US EPA Mid-Continent Ecology Division, Duluth, MN, USA
| | - Larry J. Heinis
- US Environmental Protection Agency, Great Lakes Toxicology and Ecology Division, Duluth, MN, USA
| | - Kathleen M. Jensen
- US Environmental Protection Agency, Great Lakes Toxicology and Ecology Division, Duluth, MN, USA
| | - Michael D. Kahl
- US Environmental Protection Agency, Great Lakes Toxicology and Ecology Division, Duluth, MN, USA
| | - Rebecca Y. Milsk
- ORISE Participant, US EPA Mid-Continent Ecology Division, Duluth, MN, USA
| | - Shane T. Poole
- Student Services Contractor, US EPA Mid-Continent Ecology Division, Duluth, MN, USA
| | - Eric C. Randolph
- ORISE Participant, US EPA Mid-Continent Ecology Division, Duluth, MN, USA
| | - Travis W. Saari
- Student Services Contractor, US EPA Mid-Continent Ecology Division, Duluth, MN, USA
| | - Karen H. Watanabe
- School of Mathematical and Natural Sciences, Arizona State University, Glendale, AZ 85306-4908
| | - Gerald T. Ankley
- US Environmental Protection Agency, Great Lakes Toxicology and Ecology Division, Duluth, MN, USA
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Kadlec SM, Blackwell BR, Blanksma CA, Johnson RD, Olker JH, Schoff PK, Mount DR. Gonadal Development in Smallmouth Bass (Micropterus Dolomieu) Reared in the Absence and Presence of 17-α-Ethinylestradiol. Environ Toxicol Chem 2022; 41:1416-1428. [PMID: 35199887 DOI: 10.1002/etc.5320] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Revised: 11/21/2021] [Accepted: 02/21/2022] [Indexed: 06/14/2023]
Abstract
Testicular oocytes in wild adult bass (Micropterus spp.) are considered a potential indication of exposure to estrogenic compounds in municipal, agricultural, or industrial wastewater. However, our ability to interpret links between testicular oocyte occurrence in wild fish species and environmental pollutants is limited by our understanding of normal and abnormal gonadal development. We previously reported low-to-moderate testicular oocyte prevalence (7%-38%) among adult male bass collected from Minnesota waters with no known sources of estrogenic compounds. In the present study, two experiments were conducted in which smallmouth bass (Micropterus dolomieu) fry were exposed to control water or 17-α-ethinylestradiol (EE2) during gonadal differentiation, then reared in clean water for an additional period. Histological samples were evaluated at several time points during the exposure and grow-out periods, and the sequence and timing of gonadal development in the presence of estrogen were compared with that of control fish. Testicular oocytes were not observed in any control or EE2-exposed fish. Among groups exposed to 1.2 or 5.1 ng/L EE2 in Experiment 1 or 3.0 ng/L EE2 in Experiment 2, ovaries were observed in 100% of fish up to 90 days after exposure ceased, and approximately half of those ovaries had abnormal characteristics, suggesting that they likely developed in sex-reversed males. Groups exposed to 0.1, 0.4, or 1.0 ng/L in Experiment 2 developed histologically normal ovaries and testes in proportions not significantly different from 1:1. These findings suggest that, while presumably able to cause sex reversal, juvenile exposure to EE2 may not be a unique cause of testicular oocytes in wild bass, although the long-term outcomes of exposure are unknown. Environ Toxicol Chem 2022;41:1416-1428. © 2022 SETAC. This article has been contributed to by U.S. Government employees and their work is in the public domain in the USA.
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Affiliation(s)
- Sarah M Kadlec
- Integrated Biosciences Graduate Program, University of Minnesota, Duluth, Minnesota, USA
- U.S. EPA, Office of Research and Development, Great Lakes Toxicology and Ecology Division, Duluth, Minnesota, USA
| | - Brett R Blackwell
- U.S. EPA, Office of Research and Development, Great Lakes Toxicology and Ecology Division, Duluth, Minnesota, USA
| | - Chad A Blanksma
- U.S. EPA, Office of Research and Development, Great Lakes Toxicology and Ecology Division, Duluth, Minnesota, USA
- Badger Technical Services, Duluth, Minnesota, USA
| | - Rodney D Johnson
- Integrated Biosciences Graduate Program, University of Minnesota, Duluth, Minnesota, USA
- U.S. EPA, Office of Research and Development, Great Lakes Toxicology and Ecology Division, Duluth, Minnesota, USA
| | - Jennifer H Olker
- U.S. EPA, Office of Research and Development, Great Lakes Toxicology and Ecology Division, Duluth, Minnesota, USA
- Natural Resources Research Institute, University of Minnesota-Duluth, Duluth, Minnesota, USA
| | - Patrick K Schoff
- Integrated Biosciences Graduate Program, University of Minnesota, Duluth, Minnesota, USA
- Natural Resources Research Institute, University of Minnesota-Duluth, Duluth, Minnesota, USA
| | - David R Mount
- Integrated Biosciences Graduate Program, University of Minnesota, Duluth, Minnesota, USA
- U.S. EPA, Office of Research and Development, Great Lakes Toxicology and Ecology Division, Duluth, Minnesota, USA
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Cavallin JE, Ankley GT, Blackwell BR, Blanksma CA, Fay KA, Jensen KM, Kahl MD, Knapen D, Kosian PA, Poole S, Randolph EC, Schroeder AL, Vergauwen L, Villeneuve DL. Impaired swim bladder inflation in early life stage fathead minnows exposed to a deiodinase inhibitor, iopanoic acid. Environ Toxicol Chem 2017; 36:2942-2952. [PMID: 28488362 PMCID: PMC5733732 DOI: 10.1002/etc.3855] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 02/24/2017] [Revised: 04/28/2017] [Accepted: 05/06/2017] [Indexed: 05/21/2023]
Abstract
Inflation of the posterior and/or anterior swim bladder is a process previously demonstrated to be regulated by thyroid hormones. We investigated whether inhibition of deiodinases, which convert thyroxine (T4) to the more biologically active form, 3,5,3'-triiodothyronine (T3), would impact swim bladder inflation. Two experiments were conducted using a model deiodinase inhibitor, iopanoic acid (IOP). First, fathead minnow embryos were exposed to 0.6, 1.9, or 6.0 mg/L or control water until 6 d postfertilization (dpf), at which time posterior swim bladder inflation was assessed. To examine anterior swim bladder inflation, a second study was conducted with 6-dpf larvae exposed to the same IOP concentrations until 21 dpf. Fish from both studies were sampled for T4/T3 measurements and gene transcription analyses. Incidence and length of inflated posterior swim bladders were significantly reduced in the 6.0 mg/L treatment at 6 dpf. Incidence of inflation and length of anterior swim bladder were significantly reduced in all IOP treatments at 14 dpf, but inflation recovered by 18 dpf. Throughout the larval study, whole-body T4 concentrations increased and T3 concentrations decreased in all IOP treatments. Consistent with hypothesized compensatory responses, deiodinase-2 messenger ribonucleic acid (mRNA) was up-regulated in the larval study, and thyroperoxidase mRNA was down-regulated in all IOP treatments in both studies. These results support the hypothesized adverse outcome pathways linking inhibition of deiodinase activity to impaired swim bladder inflation. Environ Toxicol Chem 2017;36:2942-2952. Published 2017 Wiley Periodicals Inc. on behalf of SETAC. This article is a US government work and, as such, is in the public domain in the United States of America.
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Affiliation(s)
- Jenna E. Cavallin
- Badger Technical Services, US Environmental Protection Agency, Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804, USA
- Corresponding author: Jenna Cavallin,
| | - Gerald T. Ankley
- US Environmental Protection Agency, Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804, USA
| | - Brett R. Blackwell
- US Environmental Protection Agency, Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804, USA
| | - Chad A. Blanksma
- Badger Technical Services, US Environmental Protection Agency, Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804, USA
| | - Kellie A. Fay
- University of Minnesota-Duluth, Biology Dept., US Environmental Protection Agency, Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804, USA
| | - Kathleen M. Jensen
- US Environmental Protection Agency, Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804, USA
| | - Michael D. Kahl
- US Environmental Protection Agency, Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804, USA
| | - Dries Knapen
- University of Antwerp, Zebrafishlab, Veterinary Physiology and Biochemistry, Dept. Veterinary Sciences, Universiteitsplein 1, 2610 Wilrijk, Belgium
| | - Patricia A. Kosian
- US Environmental Protection Agency, Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804, USA
| | - Shane Poole
- US Environmental Protection Agency, Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804, USA
| | - Eric C. Randolph
- ORISE Research Participation Program, US Environmental Protection Agency, Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804, USA
| | - Anthony L. Schroeder
- University of Minnesota - Crookston, Department of Biology, 2900 University Ave., Crookston, MN 56716, USA
| | - Lucia Vergauwen
- University of Antwerp, Zebrafishlab, Veterinary Physiology and Biochemistry, Dept. Veterinary Sciences, Universiteitsplein 1, 2610 Wilrijk, Belgium
- University of Antwerp, Systemic Physiological and Ecotoxicological Research (SPHERE), Dept. Biology, Groenenborgerlaan 171, 2020 Antwerp, Belgium
| | - Daniel L. Villeneuve
- US Environmental Protection Agency, Mid-Continent Ecology Division, 6201 Congdon Blvd., Duluth, MN 55804, USA
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LaLone CA, Villeneuve DL, Cavallin JE, Kahl MD, Durhan EJ, Makynen EA, Jensen KM, Stevens KE, Severson MN, Blanksma CA, Flynn KM, Hartig PC, Woodard JS, Berninger JP, Norberg-King TJ, Johnson RD, Ankley GT. Cross-species sensitivity to a novel androgen receptor agonist of potential environmental concern, spironolactone. Environ Toxicol Chem 2013; 32:2528-2541. [PMID: 23881739 DOI: 10.1002/etc.2330] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 03/07/2013] [Revised: 04/24/2013] [Accepted: 07/16/2013] [Indexed: 06/02/2023]
Abstract
Spironolactone is a pharmaceutical that in humans is used to treat conditions like hirsutism, various dermatologic afflictions, and female-pattern hair loss through antagonism of the androgen receptor. Although not routinely monitored in the environment, spironolactone has been detected downstream of a pharmaceutical manufacturer, indicating a potential for exposure of aquatic species. Furthermore, spironolactone has been reported to cause masculinization of female western mosquitofish, a response indicative of androgen receptor activation. Predictive methods to identify homologous proteins to the human and western mosquitofish androgen receptor suggest that vertebrates would be more susceptible to adverse effects mediated by chemicals like spironolactone that target the androgen receptor compared with invertebrate species that lack a relevant homolog. In addition, an adverse outcome pathway previously developed for activation of the androgen receptor suggests that androgen mimics can lead to reproductive toxicity in fish. To assess this, 21-d reproduction studies were conducted with 2 fish species, fathead minnow and Japanese medaka, and the invertebrate Daphnia magna. Spironolactone significantly reduced the fecundity of medaka and fathead minnows at 50 μg/L, whereas daphnia reproduction was not affected by concentrations as large as 500 μg/L. Phenotypic masculinization of females of both fish species was observed at 5 μg/L as evidenced by formation of tubercles in fathead minnows and papillary processes in Japanese medaka. Effects in fish occurred at concentrations below those reported in the environment. These results demonstrate how a priori knowledge of an adverse outcome pathway and the conservation of a key molecular target across vertebrates can be utilized to identify potential chemicals of concern in terms of monitoring and highlight potentially sensitive species and endpoints for testing.
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Affiliation(s)
- Carlie A LaLone
- US Environmental Protection Agency, Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, Duluth, Minnesota, USA
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Skolness SY, Blanksma CA, Cavallin JE, Churchill JJ, Durhan EJ, Jensen KM, Johnson RD, Kahl MD, Makynen EA, Villeneuve DL, Ankley GT. Propiconazole inhibits steroidogenesis and reproduction in the fathead minnow (Pimephales promelas). Toxicol Sci 2013; 132:284-97. [PMID: 23339182 DOI: 10.1093/toxsci/kft010] [Citation(s) in RCA: 63] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/12/2022] Open
Abstract
Conazoles are designed to inhibit cytochrome P450 (CYP) 14α-demethylase, an enzyme key to fungal cell wall formation. In vertebrates, conazoles may inhibit other CYPs, potentially disrupting processes like sex steroid synthesis. Propiconazole is a current-use pesticide that is among the first chemicals being tested in the U.S. Environmental Protection Agency endocrine disruptor screening program. Fathead minnows (Pimephales promelas) were exposed to 0, 5, 50, 500, or 1000 µg propiconazole/l in a 21-day study that evaluated apical reproductive endpoints (fecundity, fertility, hatch); measures of endocrine function and steroid synthesis, such as cholesterol, vitellogenin (VTG), and sex steroid (testosterone [T], 17β-estradiol [E2]) concentrations in the plasma; and changes in gonadal expression of steroidogenic genes. Plasma E2 and VTG concentrations in females were reduced by exposure to propiconazole, and egg production was decreased in the 500 and 1000 µg/l treatment groups. These in vivo effects coincided with inhibition of E2 synthesis by ovary explants exposed to propiconazole in vitro. We also observed a compensatory response in females exposed to propiconazole, manifested as increased gonad weight and upregulation of genes coding for key steriodogenic proteins, including CYP19 (aromatase), CYP17 (hydroxylase/lyase), CYP11A (cholesterol side-chain-cleavage), and steroidogenic acute regulatory protein. Other than an increase in relative testis weight, effects on endocrine function in males were less pronounced than in females. This study provides important data relative to the potential endocrine activity of propiconazole in fish and, more generally, to the further delineation of pathways for the reproductive effects of steroid synthesis inhibitors in fish.
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Affiliation(s)
- Sarah Y Skolness
- Department of Biology, University of Nebraska at Omaha, 6001 Dodge St., Omaha, NE 68182, USA
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LaLone CA, Villeneuve DL, Olmstead AW, Medlock EK, Kahl MD, Jensen KM, Durhan EJ, Makynen EA, Blanksma CA, Cavallin JE, Thomas LM, Seidl SM, Skolness SY, Wehmas LC, Johnson RD, Ankley GT. Effects of a glucocorticoid receptor agonist, dexamethasone, on fathead minnow reproduction, growth, and development. Environ Toxicol Chem 2012; 31:611-22. [PMID: 22189798 DOI: 10.1002/etc.1729] [Citation(s) in RCA: 78] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [What about the content of this article? (0)] [Affiliation(s)] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/25/2011] [Revised: 10/17/2011] [Accepted: 10/20/2011] [Indexed: 05/07/2023]
Abstract
Synthetic glucocorticoids are pharmaceutical compounds prescribed in human and veterinary medicine as anti-inflammatory agents and have the potential to contaminate natural watersheds via inputs from wastewater treatment facilities and confined animal-feeding operations. Despite this, few studies have examined the effects of this class of chemicals on aquatic vertebrates. To generate data to assess potential risk to the aquatic environment, we used fathead minnow 21-d reproduction and 29-d embryo-larvae assays to determine reproductive toxicity and early-life-stage effects of dexamethasone. Exposure to 500 µg dexamethasone/L in the 21-d test caused reductions in fathead minnow fecundity and female plasma estradiol concentrations and increased the occurrence of abnormally hatched fry. Female fish exposed to 500 µg dexamethasone/L also displayed a significant increase in plasma vitellogenin protein levels, possibly because of decreased spawning. A decrease in vitellogenin messenger ribonucleic acid (mRNA) expression in liver tissue from females exposed to the high dexamethasone concentration lends support to this hypothesis. Histological results indicate that a 29-d embryo-larval exposure to 500 µg dexamethasone/L caused a significant increase in deformed gill opercula. Fry exposed to 500 µg dexamethasone/L for 29 d also exhibited a significant reduction in weight and length compared with control fry. Taken together, these results indicate that nonlethal concentrations of a model glucocorticoid receptor agonist can impair fish reproduction, growth, and development.
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Affiliation(s)
- Carlie A LaLone
- Office of Research and Development, National Health and Environmental Effects Research Laboratory, Mid-Continent Ecology Division, U.S. Environmental Protection Agency, Duluth, Minnesota, USA.
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