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Philbrook NA, Nikolovska A, Maciver RD, Belanger CL, Winn LM. Characterizing the effects of in utero exposure to valproic acid on murine fetal heart development. Birth Defects Res 2019; 111:1551-1560. [PMID: 31661193 DOI: 10.1002/bdr2.1610] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/28/2019] [Revised: 09/26/2019] [Accepted: 10/09/2019] [Indexed: 12/16/2022]
Abstract
BACKGROUND Recently, the use of the antiepileptic drug valproic acid (VPA) for the treatment of psychiatric conditions has been on the rise. However, studies have shown that in utero VPA exposure can affect embryonic development, including being associated with congenital heart defects. One proposed mechanism of VPA-initiated teratogenicity is the inhibition of histone deacetylase, which is involved in the regulation of transcription factors that regulate cardiogenesis. Myocyte enhancing factor 2C (Mef2c), a transcription factor involved in the development of cardiac structure and cardiomyocyte differentiation, has been shown to increase in response to in utero VPA exposure, associating with contractile dysfunction and myocardial disorganization. METHODS To characterize the effects of VPA on murine heart development, pregnant CD-1 mice were dosed with 400 mg/kg of VPA on gestational day (GD) 9. Using high-resolution ultrasound, we examined the effects of VPA on cardiac contractile function on GD 14-18, with fetal hearts being harvested on GD 19 for histological analysis. Lastly, we conducted quantitative real-time polymerase chain reaction to measure the relative Mef2c gene expression in GD 16 murine hearts. RESULTS We observed structural anomalies at GD 19 in the hearts of VPA-treated mice. Additionally, our results showed alterations in measures of cardiac contractility, with a decrease or increase in cardiac contractile ability in VPA-treated mice depending on the GD and measurement taken. CONCLUSIONS These results further characterize the effects of VPA on heart development and suggest that alterations in Mef2c gene expression, at least on GD 16, do not mediate VPA-induced cardiotoxicity in CD-1 mice.
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Affiliation(s)
| | | | | | | | - Louise M Winn
- Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada.,School of Environmental Studies, Queen's University, Kingston, Ontario, Canada
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Ki S, Kwon SH, Eum J, Raslan AA, Kim KN, Hwang BJ, Kee Y. 3D light-sheet assay assessing novel valproate-associated cardiotoxicity and folic acid relief in zebrafish embryogenesis. CHEMOSPHERE 2019; 227:551-560. [PMID: 31004822 DOI: 10.1016/j.chemosphere.2019.04.061] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/19/2019] [Revised: 04/07/2019] [Accepted: 04/08/2019] [Indexed: 06/09/2023]
Abstract
Precise in vivo toxicological assays to determine the cardiotoxicity of pharmaceuticals and their waste products are essential in order to evaluate their risks to humans and the environment following industrial release. In the present study, we aimed to develop the sensitive imaging-based cardiotoxicity assay and combined 3D light-sheet microscopy with a zebrafish model to identify hidden cardiovascular anomalies induced by valproic acid (VPA) exposure. The zebrafish model is advantageous for this assessment because its embryos remain transparent. The 3D spatial localization of fluorescence-labeled cardiac cells in and around the heart using light-sheet technology revealed dislocalization of the heart from the outflow tract in two-day-old zebrafish embryos treated with 50 μM and 100 μM VPA (P < 0.01) and those embryos exposed to 20 μM VPA presented hypoplastic distal ventricles (P < 0.01). These two observed phenotypes are second heart field-derived cardiac defects. Quantitative analysis of the light-sheet imaging demonstrated that folic acid (FA) supplementation significantly increased the numbers of endocardial and myocardial cells (P < 0.05) and the accretion of second heart field-derived cardiomyocytes to the arterial pole of the outflow tract. The heart rate increased in response to the cellular changes occurring in embryonic heart development (P < 0.05). The present study disclosed the cellular mechanism underlying the role of FA in spontaneous cellular changes in cardiogenesis and in VPA-associated cardiotoxicity. The 3D light-sheet assay may be the next-generation test to evaluate the risks of previously undetected pharmaceutical and environmental cardiotoxicities in both humans and animals.
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Affiliation(s)
- Seoyoung Ki
- Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon, South Korea
| | - Seung-Hae Kwon
- Korea Basic Science Institute Chuncheon Center, Chuncheon, South Korea
| | - Juneyong Eum
- Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon, South Korea
| | - Ahmed A Raslan
- Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon, South Korea
| | - Kil-Nam Kim
- Korea Basic Science Institute Chuncheon Center, Chuncheon, South Korea
| | - Byung Joon Hwang
- Department of Molecular Bioscience, College of Biomedical Science, Kangwon National University, Chuncheon, South Korea.
| | - Yun Kee
- Division of Biomedical Convergence, College of Biomedical Science, Kangwon National University, Chuncheon, South Korea.
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Combining mouse embryonic stem cells and zebrafish embryos to evaluate developmental toxicity of chemical exposure. Reprod Toxicol 2018; 81:220-228. [PMID: 30103011 DOI: 10.1016/j.reprotox.2018.07.080] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/12/2017] [Revised: 03/28/2018] [Accepted: 07/13/2018] [Indexed: 12/30/2022]
Abstract
The assays in this study utilize mouse embryonic stem cells (mESCs) and zebrafish embryos to evaluate the potential developmental toxicity of industrial and pharmaceutical chemicals. A set of eleven chemicals of known mammalian in vivo teratogenicity were tested in the assays and correlations to mammalian data. Using mESCs, proliferation, differentiation, and cytotoxicity of the chemicals were measured. In zebrafish embryos, lethality and the lowest effect level concentrations for morphological malformations were determined. Clustering of the assays based on frequency of affected assays resulted in a ranking of the test compounds that correlated to in vivo rodent data (R = 0.88, P < 0.001). We conclude that the combination of ESC- and zebrafish-based assays provides a valuable platform for the prioritization of pharmaceutical and industrial chemicals for further testing of developmental toxicity in rodents.
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The Phosphorylation State of GSK3β Serine 9 Correlated to the Development of Valproic Acid-Associated Fetal Cardiac Teratogenicity, Fetal VPA Syndrome, Rescued by Folic Acid Administration. Cardiovasc Toxicol 2015; 16:34-45. [DOI: 10.1007/s12012-015-9316-0] [Citation(s) in RCA: 9] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/23/2023]
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Lamparter C, Winn LM. Tissue-specific effects of valproic acid on DNA repair genes and apoptosis in postimplantation mouse embryos. Toxicol Sci 2014; 141:59-67. [PMID: 24913804 PMCID: PMC4833099 DOI: 10.1093/toxsci/kfu105] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2014] [Accepted: 05/21/2014] [Indexed: 11/13/2022] Open
Abstract
Exposure to the anticonvulsant drug valproic acid (VPA) is associated with an increased risk of congenital malformations. Although the mechanisms contributing to its teratogenicity are poorly understood, VPA has been shown to induce DNA double strand breaks (DSB) and to increase homologous recombination in vitro. The objective of the present study was to determine whether in utero exposure to VPA alters the frequency of intrachromosomal recombination and the expression of several genes involved in DSB repair in pKZ1 mouse embryos. Pregnant pKZ1 transgenic mice (GD 9.0) were administered VPA (500 mg/kg s.c.) and embryos were extracted and microdissected into the head, heart, and trunk regions 1, 3, 6, and 24 h after injection. Quantitative PCR was used to measure the tissue-specific expression of lacZ, a surrogate measure of recombination, Xrcc4, Rad51, Brca1, and Brca2, with Western blotting used to quantify Rad51, cleaved caspase-3 and cleaved-PARP protein. Increased recombination was only observed in the embryonic head following 6-h VPA exposure. VPA had no effect on Xrcc4 expression. Rad51, Brca1, and Brca2 expression rapidly decreased in head and trunk tissues after 1-h VPA exposure, followed by a subsequent increase in all tissues, although it was generally attenuated in the head and not due to differences in endogenous levels. Cleaved caspase-3 and cleaved-PARP expression was increased in all tissues 3 h following VPA exposure. This study indicates that the tissue-specific expression of several genes involved in DSB repair is altered following exposure to VPA and may be contributing to increased apoptosis.
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Affiliation(s)
- Christina Lamparter
- Graduate Program in Pharmacology and Toxicology, Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada
| | - Louise M Winn
- Graduate Program in Pharmacology and Toxicology, Department of Biomedical and Molecular Sciences, Queen's University, Kingston, Ontario, Canada School of Environmental Studies, Queen's University, Kingston, Ontario, Canada
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Di Renzo F, Giavini E, Menegola E. Methionine Pretreatment Enhances the Effects of Valproate on Axial Development in a CD1 Mouse Model. ACTA ACUST UNITED AC 2013; 98:328-33. [DOI: 10.1002/bdrb.21069] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/27/2013] [Accepted: 07/10/2013] [Indexed: 01/25/2023]
Affiliation(s)
- Francesca Di Renzo
- Department of Biosciences; Università degli Studi di Milano; Milan; Italy
| | - Erminio Giavini
- Department of Biosciences; Università degli Studi di Milano; Milan; Italy
| | - Elena Menegola
- Department of Biosciences; Università degli Studi di Milano; Milan; Italy
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Kutlu Ö, Cansu A, Karagüzel E, Gürgen SG, Koç Ö, Gür M, Özgür GK. Effect of valproic acid treatment on penile structure in prepubertal rats. Epilepsy Res 2012; 99:306-11. [DOI: 10.1016/j.eplepsyres.2011.12.010] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/11/2011] [Revised: 11/28/2011] [Accepted: 12/18/2011] [Indexed: 11/16/2022]
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Wu M, Khan IA, Dasmahapatra AK. Valproate-induced teratogenesis in Japanese rice fish (Oryzias latipes) embryogenesis. Comp Biochem Physiol C Toxicol Pharmacol 2012; 155:528-37. [PMID: 22249148 DOI: 10.1016/j.cbpc.2012.01.003] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/16/2011] [Revised: 01/04/2012] [Accepted: 01/05/2012] [Indexed: 01/18/2023]
Abstract
Fertilized eggs of Japanese rice fish (medaka) at three developmental stages (Iwamatsu stages 4-30) were exposed to waterborne valproic acid (VPA) (0-80 mM) in hatching solution for 48 h. The amount of valproate to cause 50% mortality (IC(50)) is found to be developmental stage-specific. The embryos were more sensitive to valproate at early stages of development (Iwamatsu stages 4-10) than in the embryos in late stages (Iwamatsu stages 17-30). Valproate exposed embryos have microcephaly and disrupted cardiovasculature with delayed vessel circulation, thrombus formation, and slow heart rate. The hatching efficiency is also reduced by valproate exposure due to developmental delay. The mRNA analysis of nine genes belong to oxidative stress (catalase, gsr, gst), neurogenesis (iro3, wnt1, shh, otx2, nlgn3b) and cell cycle regulation (ccna2) have been done. It was observed that the genes belong to oxidative stress remained unaltered after valproate exposure. However, some of the genes belong to neurogenesis (wnt1,shh, otx2 and nlgn3b) and cell cycle (ccna2) showed developmental stage-specific alteration after valproate exposure. This study indicates that valproate is able to induce some of the phenotypic features which are analogous to human fetal valproate syndrome (FVS). Modulation of genes expressed in neural tissues indicates that this fish can be used to analyze the mechanisms of many neurobehavioral disorders like Autism spectrum disorder (ASD) in human.
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Affiliation(s)
- Mengmeng Wu
- National Center for Natural Products Research, University of Mississippi, University, Mississippi 38677, USA
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Purssell E, Weston AD, Thomson JJ, Swanson TA, Brown NA, Ozolinš TR. Noninvasive high-resolution ultrasound reveals structural and functional deficits in dimethadione-exposed fetal rat hearts in utero. ACTA ACUST UNITED AC 2011; 95:35-46. [DOI: 10.1002/bdrb.20339] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2011] [Revised: 09/09/2011] [Accepted: 09/12/2011] [Indexed: 11/05/2022]
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Özkan H, Çetinkaya M, Köksal N, Yapici Ş. Severe fetal valproate syndrome: combination of complex cardiac defect, multicystic dysplastic kidney, and trigonocephaly. J Matern Fetal Neonatal Med 2011; 24:521-4. [DOI: 10.3109/14767058.2010.501120] [Citation(s) in RCA: 18] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
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Wu G, Nan C, Rollo JC, Huang X, Tian J. Sodium valproate-induced congenital cardiac abnormalities in mice are associated with the inhibition of histone deacetylase. J Biomed Sci 2010; 17:16. [PMID: 20219112 PMCID: PMC2841099 DOI: 10.1186/1423-0127-17-16] [Citation(s) in RCA: 31] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/03/2009] [Accepted: 03/10/2010] [Indexed: 11/10/2022] Open
Abstract
Background Valproic acid, a widely used anticonvulsant drug, is a potent teratogen resulting in various congenital abnormalities. However, the mechanisms underlying valproic acid induced teratogenesis are nor clear. Recent studies indicate that histone deacetylase is a direct target of valproic acid. Methods In the present study, we have used histological analysis and RT-PCR assays to examine the cardiac abnormalities in mice treated with sodium valproate (NaVP) and determined the effects of NaVP on histone deacetylase activity and the expression of heart development-related genes in mouse myocardial cells. Results The experimental data show that NaVP can induce cardiac abnormalities in fetal mice in a dose-dependent manner. NaVP causes a dose-dependent inhibition of hitone deacetylase (HDAC) activity in mouse myocardial cells. However, the expression levels of HDAC (both HDAC1 and HDAC2) are not significantly changed in fetal mouse hearts after administration of NaVP in pregnant mice. The transcriptional levels of other heart development-related genes, such as CHF1, Tbx5 and MEF2, are significantly increased in fetal mouse hearts treated with NaVP. Conclusions The study indicates that administration of NaVP in pregnant mice can result in various cardiac abnormalities in fetal hearts, which is associated with an inhibition of histone deacetylase without altering the transcription of this enzyme.
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Affiliation(s)
- Gang Wu
- Department of Cardiology, the Children's Hospital of Chongqing Medical University, Chongqing, China
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Michaelis M, Suhan T, Michaelis UR, Beek K, Rothweiler F, Tausch L, Werz O, Eikel D, Zörnig M, Nau H, Fleming I, Doerr HW, Cinatl J. Valproic acid induces extracellular signal-regulated kinase 1/2 activation and inhibits apoptosis in endothelial cells. Cell Death Differ 2005; 13:446-53. [PMID: 16167071 DOI: 10.1038/sj.cdd.4401759] [Citation(s) in RCA: 69] [Impact Index Per Article: 3.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023] Open
Abstract
The histone deacetylase (HDAC) inhibitor valproic acid (VPA) was recently shown to inhibit angiogenesis, but displays no toxicity in endothelial cells. Here, we demonstrate that VPA increases extracellular signal-regulated kinase 1/2 (ERK 1/2) phosphorylation in human umbilical vein endothelial cells (HUVEC). The investigation of structurally modified VPA derivatives revealed that the induction of ERK 1/2 phosphorylation is not correlated to HDAC inhibition. PD98059, a pharmacological inhibitor of the mitogen-activated protein kinase kinase 1/2, prevented the VPA-induced ERK 1/2 phosphorylation. In endothelial cells, ERK 1/2 phosphorylation is known to promote cell survival and angiogenesis. Our results showed that VPA-induced ERK 1/2 phosphorylation in turn causes phosphorylation of the antiapoptotic protein Bcl-2 and inhibits serum starvation-induced HUVEC apoptosis and cytochrome c release from the mitochondria. Moreover, the combination of VPA with PD98059 synergistically inhibited angiogenesis in vitro and in vivo.
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Affiliation(s)
- M Michaelis
- Institut für Medizinische Virologie, Klinikum der J.W. Goethe-Universität, Paul Ehrlich-Str. 40, 60596 Frankfurt am Main, Germany
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Arndt TL, Stodgell CJ, Rodier PM. The teratology of autism. Int J Dev Neurosci 2005; 23:189-99. [PMID: 15749245 DOI: 10.1016/j.ijdevneu.2004.11.001] [Citation(s) in RCA: 245] [Impact Index Per Article: 12.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2004] [Revised: 11/22/2004] [Accepted: 11/22/2004] [Indexed: 10/25/2022] Open
Abstract
Autism spectrum disorders affect behaviors that emerge at ages when typically developing children become increasingly social and communicative, but many lines of evidence suggest that the underlying alterations in the brain occur long before the period when symptoms become obvious. Studies of the behavior of children in the first year of life demonstrate that symptoms are often detectable in the first 6 months. The environmental factors known to increase the risk of autism have critical periods of action during embryogenesis. Minor malformations that occur frequently in people with autism are known to arise in the same stages of development. Anomalies reported from histological studies of the brain are consistent with an early alteration of development. Congenital syndromes with high rates of autism include somatic that originate early in the first trimester. In addition, it is possible to duplicate a number of anatomic and behavioral features characteristic of human cases by exposing rat embryos to a teratogenic dose of valproic acid at the time of neural tube closure.
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Affiliation(s)
- Tara L Arndt
- Department of Obstetrics and Gynecology, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester, NY 14642, USA
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ten Berg K, van Oppen ACC, Nikkels PGJ, Gittenberger-de Groot AC, van der Voet GB, Brilstra EH, Lindhout D. Complex cardiac defect with hypoplastic right ventricle in a fetus with valproate exposure. Prenat Diagn 2005; 25:156-8. [PMID: 15712340 DOI: 10.1002/pd.1098] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
We describe a fetus with a hypoplastic right ventricle detected by prenatal ultrasound examination. A possible causal relationship with prenatal valproate exposure is discussed.
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Affiliation(s)
- K ten Berg
- Department of Medical Genetics, University Medical Center Utrecht, The Netherlands.
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Na L, Wartenberg M, Nau H, Hescheler J, Sauer H. Anticonvulsant valproic acid inhibits cardiomyocyte differentiation of embryonic stem cells by increasing intracellular levels of reactive oxygen species. BIRTH DEFECTS RESEARCH. PART A, CLINICAL AND MOLECULAR TERATOLOGY 2003; 67:174-80. [PMID: 12797459 DOI: 10.1002/bdra.10030] [Citation(s) in RCA: 55] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
BACKGROUND The anticonvulsant valproic acid (VPA) exerts teratogenic properties and has been demonstrated to cause neural tube defects and malformations of the heart. The effect of VPA on the differentiation of cardiomyocytes from pluripotent murine embryonic stem cells (ES cells) was investigated. METHODS Embryoid bodies derived from ES cells were treated with different concentrations of VPA and the differentiation of cardiomyocytes was monitored by immunohistochemical staining for sarcomeric alpha-actinin. Cytotoxicity was evaluated by the use of the dead cell stain SYTOX green. Intracellular levels of reactive oxygen species (ROS) within the tissue were evaluated by the use of the redox-sensitive dye dichlorodihydrofluorescein diacetate (H2DCFDA). RESULTS VPA retarded the growth of ES cell-derived embryoid bodies but did not exert cytotoxic effects. The compound dose-dependently inhibited the development of spontaneously beating clusters of cardiomyocytes within embryoid bodies grown from ES cells and reduced the extension of beating areas of cardiac cells. Furthermore, VPA significantly increased ROS levels, indicating that VPA altered the intracellular redox balance. To investigate whether the inhibition of cardiomyocyte differentiation by VPA was owing to increased ROS overwhelming the intracellular antioxidative defense, the compound was coadministered with the free radical scavenger vitamin E. CONCLUSIONS This treatment significantly restored cardiomyogenic differentiation, indicating that VPA inhibits cardiomyogenesis of ES cells by increasing intracellular ROS levels.
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Affiliation(s)
- Lan Na
- School of Physical Education, Northeast Normal University, Changchun, People's Republic of China
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Whitsel AI, Johnson CB, Forehand CJ. An in ovo chicken model to study the systemic and localized teratogenic effects of valproic acid. TERATOLOGY 2002; 66:153-63. [PMID: 12353211 DOI: 10.1002/tera.10093] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/07/2022]
Abstract
BACKGROUND The antiepileptic valproic acid (VPA) is a teratogen whose embryopathic mechanism(s) remain uncertain. Elucidating potential cellular and molecular effects of VPA is complicated by systemic application paradigms. We developed an in ovo model to reproduce the teratogenic effects of VPA and a localized VPA application procedure to determine whether VPA can selectively effect abnormal development in one region of the embryo. METHODS VPA was applied topically to chicken embryos in ovo at different embryonic stages. Embryos were later evaluated for gross and skeletal anomalies. Pax-2 and Pax-6 protein expression in the developing eye was also evaluated because VPA-induced eye anomalies are similar to those seen by the disruption of Pax-2 and Pax-6. For localized application, a thin sheet of the synthetic polymer Elvax was impregnated with VPA. A small piece of the VPA-impregnated polymer was applied directly to the presumptive wing bud region in Stage 10-17 embryos. Embryos were examined for gross and skeletal anomalies. Sham controls were employed for all experiments. RESULTS Chicken embryos exposed to VPA in ovo demonstrated increased mortality, growth delay and anomalies similar to ones previously seen in humans: neural tube, cardiovascular, craniofacial, limb and skeletal. Pax-2 and Pax-6 protein expression was qualitatively diminished in the eye. Localized wing bud VPA exposure caused structural abnormalities in the developing wing in the absence of other anomalies in the embryos. These wing defects were similar to those observed after topical whole-embryo VPA application. CONCLUSIONS These results indicate that at least one mechanism for the teratogenicity of VPA involves a direct effect on developing tissue. The nature of the abnormalities observed implies that this effect may be mediated by disruption of genes that regulate pattern formation.
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Affiliation(s)
- Amy I Whitsel
- Department of Obstetrics and Gynecology, University of Vermont College of Medicine, Burlington, Vermont 05401
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Galis F, Metz JA. Testing the vulnerability of the phylotypic stage: on modularity and evolutionary conservation. THE JOURNAL OF EXPERIMENTAL ZOOLOGY 2001; 291:195-204. [PMID: 11479918 DOI: 10.1002/jez.1069] [Citation(s) in RCA: 93] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The phylotypic stage is the developmental stage at which vertebrates most resemble each other. In this study we test the plausibility of the hypotheses of Sander [1983, Development and Evolution, Cambridge University Press] and Raff [1994, Early Life on Earth, Columbia University Press; 1996, The Shape of Life, University of Chicago Press] that the phylotypic stage is conserved due to the intense and global interactivity occurring during that stage. First, we test the prediction that the phylotypic stage is much more vulnerable than any other stage. A search of the teratological literature shows that disturbances at this stage lead to a much higher mortality than in other stages, in accordance with the prediction. Second, we test whether that vulnerability is indeed caused by the interactiveness and lack of modularity of the inductions or, alternatively, is caused by some particularly vulnerable process going on at that time. From the pattern of multiple induced anomalies we conclude that it is indeed the interactiveness that is the root cause of the vulnerability. Together these results support the hypotheses of Sander and Raff. We end by presenting an argument on why the absence of modularity in the inductive interactions may also be the root cause of the conservation of the much discussed temporal and spatial colinearity of the Hox genes. J. Exp. Zool. (Mol. Dev. Evol.) 291:195-204, 2001.
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Affiliation(s)
- F Galis
- Institute of Evolutionary and Ecological Sciences (EEW), Section Theoretical Evolutionary Biology, Leiden University, Kaiserstraat 63, 2311 GP Leiden, The Netherlands
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Kozma C. Valproic acid embryopathy: Report of two siblings with further expansion of the phenotypic abnormalities and a review of the literature. ACTA ACUST UNITED AC 2001. [DOI: 10.1002/1096-8628(20010115)98:2<168::aid-ajmg1026>3.0.co;2-o] [Citation(s) in RCA: 114] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/09/2022]
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Craig JC, Westerman ME, Dimichele L, Finnell RH. Screening for reproductive toxicity in Fundulus heteroclitus by genetic expression profiling. Biomarkers 1996; 1:123-35. [PMID: 23888923 DOI: 10.3109/13547509609088680] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/13/2022]
Abstract
Abstract Potentially teratogenic agents enter the environment at a rate that greatly exceeds current capabilities to effectively evaluate their reproductive toxicities. This is due, in part, to costly, labour-intensive methodologies involving mammalian embryonic screening assays that are currently in use worldwide. Therefore, we sought to develop a rapid, less expensive screening system with which to identify molecular biomarkers of teratogenicity using a non-mammalian system. Embryos of the topminnow, Fundulus heteroclitus, offer several advantages in terms of reproductive toxicity screening efficiency as compared with mammalian embryonic systems. These embryos are easily manipulated and develop normally at ambient temperature in air, water, or air-saturated mineral oils, making them readily adapted for field studies. In the present study, developing f. heteroclhs embryos were exposed to teratogenic concentrations of sodium valproate (VPA) or arsenic acid (arsenate), and the frequency and types of induced malformations were evaluated. Using in situ transcription and antisense RNA (aRNA) amplification procedures (IST/aRNA), we attempted to correlate the teratogenic outcomes to specific alterations in the expression of a panel of developmentally regulated genes. Preliminary studies identified treatment concentrations of arsenate and VPA that induced abnormal development in 95 % of the surviving embryos. Among the F. heteroclitus embryos, the structural defects most commonly induced by these compounds were cardiac and neural tube malformations. The genetic expression profiles revealed a number of genes whose expression levels were significantly altered by exposure to the test compounds. Molecular analysis of f. heteroclitus embryonic development represents a novel, inexpensive approach to screen for potential teratogens, and identify genes whose expression patterns may be used as biomarkers, or indicators, of teratogenicity.
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