Monitoring estrogenic activities of waste and surface waters using a novel in vivo zebrafish embryonic (EASZY) assay: Comparison with in vitro cell-based assays and determination of effect-based trigger values

• Published in: Environment international Vol. 130; p. 104896
• Main Authors: Brion, François, De Gussem, Valentin, Buchinger, Sebastian, Hollert, Henner, Carere, Mario, Porcher, Jean-Marc, Piccini, Benjamin, Féray, Christine, Dulio, Valeria, Könemann, Sarah, Simon, Eszter, Werner, Inge, Kase, Robert, Aït-Aïssa, Selim
• Format: Journal Article
• Language: English
• Published: Netherlands Elsevier Ltd 01-09-2019; Elsevier
• Subjects: Animals; Biological Assay; Correlation; Ecotoxicology; Effect-based trigger value; Embryo, Nonmammalian - drug effects; Environmental Monitoring - methods; Estradiol - analysis; Estradiol - toxicity; Estrogen monitoring; Estrogens - analysis; Estrogens - toxicity; Fresh Water - analysis; In vitro and in vivo bioassays; Life Sciences; Toxicity Tests; Toxicology; Water Pollutants, Chemical - analysis; Water Pollutants, Chemical - toxicity; Zebrafish; Estrogen monitoring; Zebrafish; Correlation; In vitro and in vivo bioassays; Effect-based trigger value; IN VITRO AND IN VIVO BIOASSAYS; CORRELATION; ZEBRAFISH; ESTROGEN MONITORING; EFFECT-BASED TRIGGER VALUE
• ISSN: 0160-4120; 1873-6750
• DOI: 10.1016/j.envint.2019.06.006

This study reports the use of the recently developed EASZY assay that uses transgenic cyp19a1b-GFP zebrafish (Danio rerio) embryos to assess in vivo estrogenic activity of 33 surface (SW) and waste water (WW) samples collected across Europe that were previously well-characterized for estrogen hormones and in vitro estrogenic activity. We showed that 18 out of the 33 SW and WW samples induced estrogenic responses in the EASZY assay leading to a significant and concentration-dependent up-regulation of the ER-regulated cyp19a1b gene expression in the developing brain. The in vivo 17β-estradiol-equivalents (EEQs) were highly correlated with, both, the chemical analytical risk quotient (RQ) based on steroidal estrogen concentrations and EEQs reported from five different in vitro reporter gene assays. Regression analyses between the vitro and in vivo effect concentrations allowed us to determine an optimal cut-off value for each in vitro assay, above which in vivo responses were observed. These in vitro assay-specific effect-based trigger values (EBTs), ranging from 0.28 to 0.58 ng EEQ/L define the sensitivity and specificity of the individual in vitro assays for predicting a risk associated with substances acting through the same mode of action in water samples. Altogether, this study demonstrates the toxicological relevance of in vitro-based assessment of estrogenic activity and recommends the use of such in vitro/in vivo comparative approach to refine and validate EBTs for mechanism-based bioassays.
•Estrogenic activity of 33 water samples was assessed in a transgenic zebrafish assay.•In vivo EEQs were correlated with EEQs from 5 in vitro assays.•In vivo EEQs were correlated with risk quotient based on E1, E2, EE2 concentrations.•In vitro Assay-specific effect-based triggers values were defined.•Improvement of sensitivity and sensitivity for risk prediction of estrogens