- Email: [email protected]
The virtual embryo project (v-Embryo™)
ETS Abstracts 2008 / Reproductive Toxicology xxx (2008) xxx–xxx
The virtual embryo project (v-EmbryoTM ) Knudsen 1 ,
Kavlock 1 ,
T.B. R.J. I. Singh 3 , C. Lau 2 , E.S. Hunter 2
Shah 1 ,
D.J.
Dix 1 ,
R.S.
Judson 1 ,
A.V.
1
National Center for Computational Toxicology, NC 27711, USA NHEERL - Reproductive Toxicology Division, Office of Research and Development, US EPA, NC 27711, USA 3 Lockheed Martin, Research Triangle Park, NC 27711, USA 2
The v-EmbryoTM is a far reaching new research program at the US EPA to develop a working computer model of a mammalian embryo that can be used to better understand the prenatal risks posed by environmental chemicals and to eventually predict a chemical’s potential developmental toxicity in silico. The basic concept is a public portal, knowlegebase, and computational infrastructure for modeling genetic-cellular networks and developmental toxicity pathways. The v-EmbryoTM research platform addresses the hypothesis that critical effects of environmental agents on developmental toxicity pathways may be encoded as computer simulations of morphogenetic processes that draw from knowledge regarding the flow of molecular regulatory information in rudimentary tissues, the cell-autonomous responses to genetic and environmental signals, and the emergent morphogenetic properties associated with collective cellular behavior in any given system. Computational techniques to dissect the relative contributions of genetic variation, stage vulnerability, dose-response patterns, chemical mechanisms, fetal (epigenetic) programming, and maternal–fetal interactions to developmental defects are being built to investigate systematically interactions between these complex variables. Through these resources we can ultimately hope to predict lever-points for toxicity pathways and cellular networks that perturb development. The v-EmbryoTM (http://www.epa.gov/ncct/v-Embryo/) is piloting a Wiki-space for information sharing (http://v-embryo.wikispaces.com/) and aligns with other high-throughput screening assays and systems biology research initiatives at the National Center for Computational Toxicology (NCCT) including ACToR, ToxCastTM , and the Virtual Liver. [This work has been reviewed by EPA and approved for publication but does not necessarily reflect official Agency policy]. doi:10.1016/j.reprotox.2008.05.027 Development of the Auditory Startle Reflex in Juvenile Wistar Rats Geertje Lewin ∗ , Jochen Buschmann, Rainer Fuhst Fraunhofer Institute of Toxicology and Experimental Medicine, Hannover, Germany The Auditory Startle Reflex (ASR) is a transient motor response mediated by the brainstem to an unexpected, intense acoustic stimulus. It represents a sensitive, non-invasive measurement of central nervous system activity and can be applied to assess auditory function and cerebral gating ability. During ASR measurement, the latency, intensity and duration of the reaction to a sudden short acoustic signal is quantified, the habituation to a repeated signal is assessed and the pre-pulse inhibition (the reduced startle reflex after a “warning” signal) can be measured. Increases in the response to acoustic stimuli and a shorter latency are described in Attention-Deficit Hyperactivity Disorder (ADHD) and fragile X-syndrome while a decrease or lack in habituation can be seen in post-traumatic stress disorder and schizophrenia. In order to track the development of reflex response in juvenile rats, litters of juvenile Wistar WU were exposed to a pre-defined program of acoustic stimuli at 10, 15, 20, 40 and 60 days post
11
partum (pp) and the intensity and duration of the response to acoustic stimuli as well as the progress in pre-pulse inhibition and habituation were measured. Our results demonstrate the practicability of ASR measurements as early as day 10 pp with a coordinated animal response showing a significant pre-pulse inhibition around day 15 pp, in coincidence with ear and eye opening. During the juvenile period of hyperactivity and -reactivity (around day 15–20 pp) the juvenile rats show high intensity reactions with a long duration. The development of a gender-specific response starts around day 40 pp in coincidence with sexual maturation, with females demonstrating a higher degree of habituation and pre-pulse inhibition. Adult-like patterns of habituation can be assessed by day 60 pp. In contrast to general experimental habit (assessing ASR at weaning and day 60 pp), our data demonstrate the practicability of ASR measurement at day 15 pp with comparable results, enabling an earlier assessment of cerebral function. doi:10.1016/j.reprotox.2008.05.028 Embryotoxicity of artemisinin-type compounds Monica Longo 1,∗ , Sara Zanoncelli 1 , Paolo A. Colombo 1 , Marco Brughera 1 , Guy Mazue` 2 , Piero Olliaro 3,4 1
Accelera, Nerviano Medical Sciences S.r.l, Nerviano, Milan, Italy Independent consultant, Aux Fermes de Bosne, F 39230 Mantry, France 3 UNICEF/UNDP/World Bank/WHO Special Programme on Research and Training in Tropical Diseases (TDR), Geneva, Switzerland 4 Centre for Tropical Medicine and Vaccinology, Churchill Hospital, University of Oxford, UK 2
Malaria occurring during pregnancy is dangerous for both the mother and the child. Artemisinin-type compounds are now the cornerstone of malaria case management and artemisinin-based combinations are the current first-line treatment for the treatment of uncomplicated malaria. However, these drugs are contraindicated in the first trimester of pregnancy because they cause embryo losses and malformations in experimental animals. The embryotoxicity of artemisinin-type compounds is duly followed by the World Health Organization (WHO) through periodic reviews of both experimental and clinical data to document this risk and inform treatment policies. The data available for the initial assessment in 2002 led to the conclusion that artemisinin-type compounds were embryolethal in rats and rabbits, but these data were not sufficient to determine the mechanism of embryotoxicity and to conduct a comprehensive assessment of risk for humans. Significant progress has been made since this first assessment, mainly through the work of two independent laboratories (NMS, Italy and GSK, US) that employed a combination of in vitro experiments, including whole embryo cultures (WEC), Frog Embryo Teratogenesis Assay-Xenopus (FETAX), and erythrocyte cultures, and in vivo experiments using conventional and non-conventional designs. The experimental evidence thus obtained can be summarized as follows: Artemisinin-type compounds have a narrow critical window of embryotoxicity in the rat, during gestation days (GD) 9–14 [1]. The primary mechanism of artemisinin-induced embryotoxicity in the rat is a sustained depletion of primitive, metabolically active RBCs clonally released over a short period of time from the yolk sac, which is the primitive site of haematopoiesis. Embryonic anaemia leads to tissue hypoxia and subsequent cell death which, depending on its severity and location, causes the embryo to die or allows it to survive with or without sequelae, the most common malformations being cardiovascular (great vessel abnormalities) and limb defects (shortened and/or bent long bones). Embryotoxi-
RTX 6115 1–22
The virtual embryo project (v-EmbryoTM ) Knudsen 1 ,
Kavlock 1 ,
T.B. R.J. I. Singh 3 , C. Lau 2 , E.S. Hunter 2
Shah 1 ,
D.J.
Dix 1 ,
R.S.
Judson 1 ,
A.V.
1
National Center for Computational Toxicology, NC 27711, USA NHEERL - Reproductive Toxicology Division, Office of Research and Development, US EPA, NC 27711, USA 3 Lockheed Martin, Research Triangle Park, NC 27711, USA 2
The v-EmbryoTM is a far reaching new research program at the US EPA to develop a working computer model of a mammalian embryo that can be used to better understand the prenatal risks posed by environmental chemicals and to eventually predict a chemical’s potential developmental toxicity in silico. The basic concept is a public portal, knowlegebase, and computational infrastructure for modeling genetic-cellular networks and developmental toxicity pathways. The v-EmbryoTM research platform addresses the hypothesis that critical effects of environmental agents on developmental toxicity pathways may be encoded as computer simulations of morphogenetic processes that draw from knowledge regarding the flow of molecular regulatory information in rudimentary tissues, the cell-autonomous responses to genetic and environmental signals, and the emergent morphogenetic properties associated with collective cellular behavior in any given system. Computational techniques to dissect the relative contributions of genetic variation, stage vulnerability, dose-response patterns, chemical mechanisms, fetal (epigenetic) programming, and maternal–fetal interactions to developmental defects are being built to investigate systematically interactions between these complex variables. Through these resources we can ultimately hope to predict lever-points for toxicity pathways and cellular networks that perturb development. The v-EmbryoTM (http://www.epa.gov/ncct/v-Embryo/) is piloting a Wiki-space for information sharing (http://v-embryo.wikispaces.com/) and aligns with other high-throughput screening assays and systems biology research initiatives at the National Center for Computational Toxicology (NCCT) including ACToR, ToxCastTM , and the Virtual Liver. [This work has been reviewed by EPA and approved for publication but does not necessarily reflect official Agency policy]. doi:10.1016/j.reprotox.2008.05.027 Development of the Auditory Startle Reflex in Juvenile Wistar Rats Geertje Lewin ∗ , Jochen Buschmann, Rainer Fuhst Fraunhofer Institute of Toxicology and Experimental Medicine, Hannover, Germany The Auditory Startle Reflex (ASR) is a transient motor response mediated by the brainstem to an unexpected, intense acoustic stimulus. It represents a sensitive, non-invasive measurement of central nervous system activity and can be applied to assess auditory function and cerebral gating ability. During ASR measurement, the latency, intensity and duration of the reaction to a sudden short acoustic signal is quantified, the habituation to a repeated signal is assessed and the pre-pulse inhibition (the reduced startle reflex after a “warning” signal) can be measured. Increases in the response to acoustic stimuli and a shorter latency are described in Attention-Deficit Hyperactivity Disorder (ADHD) and fragile X-syndrome while a decrease or lack in habituation can be seen in post-traumatic stress disorder and schizophrenia. In order to track the development of reflex response in juvenile rats, litters of juvenile Wistar WU were exposed to a pre-defined program of acoustic stimuli at 10, 15, 20, 40 and 60 days post
11
partum (pp) and the intensity and duration of the response to acoustic stimuli as well as the progress in pre-pulse inhibition and habituation were measured. Our results demonstrate the practicability of ASR measurements as early as day 10 pp with a coordinated animal response showing a significant pre-pulse inhibition around day 15 pp, in coincidence with ear and eye opening. During the juvenile period of hyperactivity and -reactivity (around day 15–20 pp) the juvenile rats show high intensity reactions with a long duration. The development of a gender-specific response starts around day 40 pp in coincidence with sexual maturation, with females demonstrating a higher degree of habituation and pre-pulse inhibition. Adult-like patterns of habituation can be assessed by day 60 pp. In contrast to general experimental habit (assessing ASR at weaning and day 60 pp), our data demonstrate the practicability of ASR measurement at day 15 pp with comparable results, enabling an earlier assessment of cerebral function. doi:10.1016/j.reprotox.2008.05.028 Embryotoxicity of artemisinin-type compounds Monica Longo 1,∗ , Sara Zanoncelli 1 , Paolo A. Colombo 1 , Marco Brughera 1 , Guy Mazue` 2 , Piero Olliaro 3,4 1
Accelera, Nerviano Medical Sciences S.r.l, Nerviano, Milan, Italy Independent consultant, Aux Fermes de Bosne, F 39230 Mantry, France 3 UNICEF/UNDP/World Bank/WHO Special Programme on Research and Training in Tropical Diseases (TDR), Geneva, Switzerland 4 Centre for Tropical Medicine and Vaccinology, Churchill Hospital, University of Oxford, UK 2
Malaria occurring during pregnancy is dangerous for both the mother and the child. Artemisinin-type compounds are now the cornerstone of malaria case management and artemisinin-based combinations are the current first-line treatment for the treatment of uncomplicated malaria. However, these drugs are contraindicated in the first trimester of pregnancy because they cause embryo losses and malformations in experimental animals. The embryotoxicity of artemisinin-type compounds is duly followed by the World Health Organization (WHO) through periodic reviews of both experimental and clinical data to document this risk and inform treatment policies. The data available for the initial assessment in 2002 led to the conclusion that artemisinin-type compounds were embryolethal in rats and rabbits, but these data were not sufficient to determine the mechanism of embryotoxicity and to conduct a comprehensive assessment of risk for humans. Significant progress has been made since this first assessment, mainly through the work of two independent laboratories (NMS, Italy and GSK, US) that employed a combination of in vitro experiments, including whole embryo cultures (WEC), Frog Embryo Teratogenesis Assay-Xenopus (FETAX), and erythrocyte cultures, and in vivo experiments using conventional and non-conventional designs. The experimental evidence thus obtained can be summarized as follows: Artemisinin-type compounds have a narrow critical window of embryotoxicity in the rat, during gestation days (GD) 9–14 [1]. The primary mechanism of artemisinin-induced embryotoxicity in the rat is a sustained depletion of primitive, metabolically active RBCs clonally released over a short period of time from the yolk sac, which is the primitive site of haematopoiesis. Embryonic anaemia leads to tissue hypoxia and subsequent cell death which, depending on its severity and location, causes the embryo to die or allows it to survive with or without sequelae, the most common malformations being cardiovascular (great vessel abnormalities) and limb defects (shortened and/or bent long bones). Embryotoxi-
RTX 6115 1–22