Rebecca J. Brown, Grace H. Panter, Natalie Burden, Lennart Weltje, James R. Wheeler, Edward R. Salinas, Yvonne Wolf, Laurent Lagadic
The egg-yolk precursor protein vitellogenin (VTG) is a biomarker for the determination of in vivo endocrine activity of chemicals in animals. Measurements of VTG in fish and amphibians are included in Organisation for Economic Co-operation and Development (OECD) test guidelines to provide support for identifying potential endocrine-active substances acting on the estrogen, androgen, and steroidogenesis (EAS) pathways. Induction of VTG in male fish is often associated with estrogenic activity, whereas inhibition in female fish may be related to substances that inhibit estrogen synthesis. The VTG protein or mRNA is measured in the plasma, liver, or whole body of fish, depending on the species and developmental stage, and on the specific test guideline requirements. Concerns have been raised regarding the variability of VTG measurements in fish, which could challenge the reliability and acceptability of VTG results for use in regulatory assessment of chemicals (Brown et al., 2023). Hence, it is important to correctly measure and interpret VTG results, because ambiguous effects could trigger additional, potentially unnecessary, higher tier testing (i.e., animal-intensive life-cycle studies) to confirm or refute the VTG result. A literature review of VTG data from standard fish species exposed to 106 substances showed high intra- and interlaboratory variability in VTG concentrations, as well as discrepancies in the interpretation of results based on large differences between fish held in dilution water versus solvent controls, or due to the presence of outlier measurements (Brown et al., 2023). For instance, the coefficient of variation of VTG concentrations in control adult fathead minnows (Pimephales promelas) was 543.2% for males and 206.1% for females. The same review also found evidence for false-positive/negative responses and situations in which the VTG results were difficult to interpret.
Findings from a laboratory survey to help understand the sources of variability in VTG protein and mRNA measurements identified three areas for improvement and harmonization: (1) sampling and storage, (2) quantification, and (3) data handling and statistical analysis (Burden et al., 2023).
The survey also highlighted a need for the development of a decision logic to assist in the acceptability, determination, and interpretation of VTG measurements. This would support the development of new OECD guidance detailing best practice for VTG methodology, applicable across relevant test guideline studies but also applicable to studies published in the open literature. In the proposed decision logic (Figure 1), the reliability of the VTG results is assessed separately from the overall study reliability, because a reliable study (as evaluated against, for example, the Klimisch criteria [Klimisch et al., 1997] or the Criteria for Reporting and Evaluating Ecotoxicity Data [Moermond et al., 20
{"title":"A Decision Logic for the Reliability Assessment and Interpretation of Vitellogenin Measurements","authors":"Rebecca J. Brown, Grace H. Panter, Natalie Burden, Lennart Weltje, James R. Wheeler, Edward R. Salinas, Yvonne Wolf, Laurent Lagadic","doi":"10.1002/etc.5946","DOIUrl":"10.1002/etc.5946","url":null,"abstract":"<p>The egg-yolk precursor protein vitellogenin (VTG) is a biomarker for the determination of in vivo endocrine activity of chemicals in animals. Measurements of VTG in fish and amphibians are included in Organisation for Economic Co-operation and Development (OECD) test guidelines to provide support for identifying potential endocrine-active substances acting on the estrogen, androgen, and steroidogenesis (EAS) pathways. Induction of VTG in male fish is often associated with estrogenic activity, whereas inhibition in female fish may be related to substances that inhibit estrogen synthesis. The VTG protein or mRNA is measured in the plasma, liver, or whole body of fish, depending on the species and developmental stage, and on the specific test guideline requirements. Concerns have been raised regarding the variability of VTG measurements in fish, which could challenge the reliability and acceptability of VTG results for use in regulatory assessment of chemicals (Brown et al., <span>2023</span>). Hence, it is important to correctly measure and interpret VTG results, because ambiguous effects could trigger additional, potentially unnecessary, higher tier testing (i.e., animal-intensive life-cycle studies) to confirm or refute the VTG result. A literature review of VTG data from standard fish species exposed to 106 substances showed high intra- and interlaboratory variability in VTG concentrations, as well as discrepancies in the interpretation of results based on large differences between fish held in dilution water versus solvent controls, or due to the presence of outlier measurements (Brown et al., <span>2023</span>). For instance, the coefficient of variation of VTG concentrations in control adult fathead minnows (<i>Pimephales promelas</i>) was 543.2% for males and 206.1% for females. The same review also found evidence for false-positive/negative responses and situations in which the VTG results were difficult to interpret.</p><p>Findings from a laboratory survey to help understand the sources of variability in VTG protein and mRNA measurements identified three areas for improvement and harmonization: (1) sampling and storage, (2) quantification, and (3) data handling and statistical analysis (Burden et al., <span>2023</span>).</p><p>The survey also highlighted a need for the development of a decision logic to assist in the acceptability, determination, and interpretation of VTG measurements. This would support the development of new OECD guidance detailing best practice for VTG methodology, applicable across relevant test guideline studies but also applicable to studies published in the open literature. In the proposed decision logic (Figure 1), the reliability of the VTG results is assessed separately from the overall study reliability, because a reliable study (as evaluated against, for example, the Klimisch criteria [Klimisch et al., <span>1997</span>] or the Criteria for Reporting and Evaluating Ecotoxicity Data [Moermond et al., <span>20","PeriodicalId":11793,"journal":{"name":"Environmental Toxicology and Chemistry","volume":null,"pages":null},"PeriodicalIF":3.6,"publicationDate":"2024-07-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/etc.5946","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"141558325","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"环境科学与生态学","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}