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The zebrafish embryo: Fit for all purposes?
Abstracts / Reproductive Toxicology 56 (2015) 4–10
as well as between P-ECs/immune cell (with regulatory T cells (Tregs) in particular). Finally, we are studying the mechanisms of certain iatrogenic agents, such as drugs, on pulmonary endothelial dysfunction. http://dx.doi.org/10.1016/j.reprotox.2015.07.015 S2-3 The treatment of Pulmonary Arterial Hypertension: The heart and lungs work as a single unit Andrew Peacock Scottish Pulmonary Vascular Unit, Golden Jubilee National Hospital, Glasgow, United Kingdom Pulmonary Arterial Hypertension (PAH) is characterised by remodeling of the pulmonary vessel by thickening of all three layers of the vascular wall and compensative remodeling of the right ventricle by hypertrophy. PAH remains incurable but 4 classes of medication are currently approved for PAH treatment: prostacyclin analogues, phosphodiesterase 5 inhibitors, soluble guanylate cyclase activators and endothelin receptor antagonists. These treatments reduce disease progression, increase survival and improve quality of life. The difficulty of finding a curative drug is shown by the overlapping cellular mechanisms of PAH which include harmful pulmonary vascular remodeling, as well as compensating right ventricular adaptation. Therefore, novel drugs could paradoxically be beneficial in the lungs by diminishing pulmonary vascular remodeling but concurrently harmful to the right heart by hampering myocardial adaptive hypertrophy and coronary angiogenesis. Interestingly, some of these mechanisms are similar to fetal mechanisms for cardiopulmonary development. Pregnancy is contraindicated in PAH because of the massive physiological changes that occur in the pregnant mother. When pregnancy occurs in a woman with PAH, intensive monitoring is required particularly in the last few weeks of pregnancy, the delivery and the post partum period. All the anti PAH drugs can be used with the exception of the Endothelin Receptor antagonists which are teratogenic. http://dx.doi.org/10.1016/j.reprotox.2015.07.016 Symposium 3 – The zebrafish embryo: fit for all purposes? S3-0 The zebrafish embryo: Fit for all purposes? Steven J. Van Cruchten University of Antwerp, B-2610 Wilrijk, Belgium Zebrafish (Danio rerio) embryos are currently used for acute, chronic and/or developmental toxicity testing of pharmaceuticals, chemicals and cosmetics. The strong interest in this vertebrate model can be explained by their inherent advantages (rapid development, small size, transparency, etc.) and importantly, zebrafish are not considered to be a test animal according to EU regulation (2012/707/EU) up to the age of 120 h post fertilization. The latter has definitely accelerated the research on this model in view of the REACH Regulation (EC) No. 1907/2006 and the Cosmetics Regulation (EC) No. 1223/2009. However, this pressure for (validated) alternative models for toxicity testing has also led to a plethora of study designs, endpoints and acronyms for assays using the zebrafish embryo (DarT, ZEDTA, ZFET, etc.). This has complicated the correct interpretation and extrapolation of the obtained data to other species, including man. So far, only the (zebra)fish
7
embryo test ((Z)FET; OECD TG 236), which assess acute toxicity of chemicals, has been adopted by regulatory authorities. In this assay, newly fertilized zebrafish embryos are exposed to the test chemical for a total of 96 h and the evaluation is limited to four endpoints related to lethality, i.e. coagulation of fertilized eggs, lack of somite formation, lack of detachment of the tail bud from the yolk sac and lack of heartbeat. This acute toxicity test is also used by the cosmetic industry as the Cosmetics Regulation (EC) No. 1223/2009 prohibits animal testing since July 2013. Currently, efforts are also made to replace the fish early life-stage toxicity test (FELS; OECD TG 210), a chronic toxicity test of chemicals, by a 120 hpf ZFET in combination with in vitro and in silico tests. In this regard, the Adverse Outcome Pathway (AOP) framework also plays a key role. In the AOP concept, molecular initiating events are linked to adverse outcomes at organismal level. This may help to refine assays and testing strategies for risk assessment of chemicals. In pharmaceutical industry, the zebrafish embryo is mainly used for developmental toxicity screening. This may be as a stand-alone assay or part of a testing battery depending on the policy of the pharmaceutical company. Although the duration of exposure (96 h) is very similar to the ZFET, the protocol is much less standardized. Different strains, media and endpoints are used, which complicates the interpretation and extrapolation of the results. Therefore, efforts are still ongoing to harmonize and validate this developmental toxicology assay. In conclusion, the zebrafish embryo is a widely used model in toxicology, but the study designs, endpoints and derived parameters may differ substantially depending on the scope for and nature of the compound. http://dx.doi.org/10.1016/j.reprotox.2015.07.017 S3-1 The expanding role of the zebrafish model in pharmaceutical testing Jonathan Ball Exeter University, UK The pharmaceutical industry has a need, both economic and ethical, to seek alternative approaches to mammalian testing to screen/design out safety side effects at an early stage of the drug development pipeline. One of the most advanced and most utilised models is the freshwater teleost, zebrafish (Danio rerio), which provides an adaptable model for a range of research and development needs and in particular for Safety Assessment screening. In this presentation we will highlight some of the zebrafish assays that are commonly used as the first level of whole animal screening by the pharmaceutical industry, with particular reference to the Zebrafish Developmental Toxicity Assay (ZEDTA). The different strategies adopted across a small consortium of Pharma companies and a perspective on future uses of the ZEDTA assay, including potentially within a regulatory framework, is also discussed. http://dx.doi.org/10.1016/j.reprotox.2015.07.018
as well as between P-ECs/immune cell (with regulatory T cells (Tregs) in particular). Finally, we are studying the mechanisms of certain iatrogenic agents, such as drugs, on pulmonary endothelial dysfunction. http://dx.doi.org/10.1016/j.reprotox.2015.07.015 S2-3 The treatment of Pulmonary Arterial Hypertension: The heart and lungs work as a single unit Andrew Peacock Scottish Pulmonary Vascular Unit, Golden Jubilee National Hospital, Glasgow, United Kingdom Pulmonary Arterial Hypertension (PAH) is characterised by remodeling of the pulmonary vessel by thickening of all three layers of the vascular wall and compensative remodeling of the right ventricle by hypertrophy. PAH remains incurable but 4 classes of medication are currently approved for PAH treatment: prostacyclin analogues, phosphodiesterase 5 inhibitors, soluble guanylate cyclase activators and endothelin receptor antagonists. These treatments reduce disease progression, increase survival and improve quality of life. The difficulty of finding a curative drug is shown by the overlapping cellular mechanisms of PAH which include harmful pulmonary vascular remodeling, as well as compensating right ventricular adaptation. Therefore, novel drugs could paradoxically be beneficial in the lungs by diminishing pulmonary vascular remodeling but concurrently harmful to the right heart by hampering myocardial adaptive hypertrophy and coronary angiogenesis. Interestingly, some of these mechanisms are similar to fetal mechanisms for cardiopulmonary development. Pregnancy is contraindicated in PAH because of the massive physiological changes that occur in the pregnant mother. When pregnancy occurs in a woman with PAH, intensive monitoring is required particularly in the last few weeks of pregnancy, the delivery and the post partum period. All the anti PAH drugs can be used with the exception of the Endothelin Receptor antagonists which are teratogenic. http://dx.doi.org/10.1016/j.reprotox.2015.07.016 Symposium 3 – The zebrafish embryo: fit for all purposes? S3-0 The zebrafish embryo: Fit for all purposes? Steven J. Van Cruchten University of Antwerp, B-2610 Wilrijk, Belgium Zebrafish (Danio rerio) embryos are currently used for acute, chronic and/or developmental toxicity testing of pharmaceuticals, chemicals and cosmetics. The strong interest in this vertebrate model can be explained by their inherent advantages (rapid development, small size, transparency, etc.) and importantly, zebrafish are not considered to be a test animal according to EU regulation (2012/707/EU) up to the age of 120 h post fertilization. The latter has definitely accelerated the research on this model in view of the REACH Regulation (EC) No. 1907/2006 and the Cosmetics Regulation (EC) No. 1223/2009. However, this pressure for (validated) alternative models for toxicity testing has also led to a plethora of study designs, endpoints and acronyms for assays using the zebrafish embryo (DarT, ZEDTA, ZFET, etc.). This has complicated the correct interpretation and extrapolation of the obtained data to other species, including man. So far, only the (zebra)fish
7
embryo test ((Z)FET; OECD TG 236), which assess acute toxicity of chemicals, has been adopted by regulatory authorities. In this assay, newly fertilized zebrafish embryos are exposed to the test chemical for a total of 96 h and the evaluation is limited to four endpoints related to lethality, i.e. coagulation of fertilized eggs, lack of somite formation, lack of detachment of the tail bud from the yolk sac and lack of heartbeat. This acute toxicity test is also used by the cosmetic industry as the Cosmetics Regulation (EC) No. 1223/2009 prohibits animal testing since July 2013. Currently, efforts are also made to replace the fish early life-stage toxicity test (FELS; OECD TG 210), a chronic toxicity test of chemicals, by a 120 hpf ZFET in combination with in vitro and in silico tests. In this regard, the Adverse Outcome Pathway (AOP) framework also plays a key role. In the AOP concept, molecular initiating events are linked to adverse outcomes at organismal level. This may help to refine assays and testing strategies for risk assessment of chemicals. In pharmaceutical industry, the zebrafish embryo is mainly used for developmental toxicity screening. This may be as a stand-alone assay or part of a testing battery depending on the policy of the pharmaceutical company. Although the duration of exposure (96 h) is very similar to the ZFET, the protocol is much less standardized. Different strains, media and endpoints are used, which complicates the interpretation and extrapolation of the results. Therefore, efforts are still ongoing to harmonize and validate this developmental toxicology assay. In conclusion, the zebrafish embryo is a widely used model in toxicology, but the study designs, endpoints and derived parameters may differ substantially depending on the scope for and nature of the compound. http://dx.doi.org/10.1016/j.reprotox.2015.07.017 S3-1 The expanding role of the zebrafish model in pharmaceutical testing Jonathan Ball Exeter University, UK The pharmaceutical industry has a need, both economic and ethical, to seek alternative approaches to mammalian testing to screen/design out safety side effects at an early stage of the drug development pipeline. One of the most advanced and most utilised models is the freshwater teleost, zebrafish (Danio rerio), which provides an adaptable model for a range of research and development needs and in particular for Safety Assessment screening. In this presentation we will highlight some of the zebrafish assays that are commonly used as the first level of whole animal screening by the pharmaceutical industry, with particular reference to the Zebrafish Developmental Toxicity Assay (ZEDTA). The different strategies adopted across a small consortium of Pharma companies and a perspective on future uses of the ZEDTA assay, including potentially within a regulatory framework, is also discussed. http://dx.doi.org/10.1016/j.reprotox.2015.07.018