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Brownbill P, Chernyavsky I, Bottalico B, Desoye G, Hansson S, Kenna G, Knudsen LE, Markert UR, Powles-Glover N, Schneider H, Leach L. An international network (PlaNet) to evaluate a human placental testing platform for chemicals safety testing in pregnancy. Reprod Toxicol 2016; 64:191-202. [PMID: 27327413 DOI: 10.1016/j.reprotox.2016.06.006] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2016] [Revised: 05/23/2016] [Accepted: 06/07/2016] [Indexed: 12/14/2022]
Abstract
The human placenta is a critical life-support system that nourishes and protects a rapidly growing fetus; a unique organ, species specific in structure and function. We consider the pressing challenge of providing additional advice on the safety of prescription medicines and environmental exposures in pregnancy and how ex vivo and in vitro human placental models might be advanced to reproducible human placental test systems (HPTSs), refining a weight of evidence to the guidance given around compound risk assessment during pregnancy. The placental pharmacokinetics of xenobiotic transfer, dysregulated placental function in pregnancy-related pathologies and influx/efflux transporter polymorphisms are a few caveats that could be addressed by HPTSs, not the specific focus of current mammalian reproductive toxicology systems. An international consortium, "PlaNet", will bridge academia, industry and regulators to consider screen ability and standardisation issues surrounding these models, with proven reproducibility for introduction into industrial and clinical practice.
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Affiliation(s)
- Paul Brownbill
- Maternal and Fetal Health Research Centre, Institute of Human Development, Faculty of Medical and Human Sciences, University of Manchester, Manchester, UK; Mary's Hospital, Central Manchester University Hospitals NHS Foundation Trust, Manchester Academic Health Science Centre, Manchester, UK.
| | - Igor Chernyavsky
- School of Mathematics, University of Manchester, Manchester, UK.
| | - Barbara Bottalico
- Department of Obstetrics and Gynecology, Institute of Clinical Sciences, Lund University, Lund, Sweden,.
| | - Gernot Desoye
- Department of Obstetrics and Gynecology, Medical University of Graz, Graz, Austria.
| | - Stefan Hansson
- Department of Obstetrics and Gynecology, Institute of Clinical Sciences, Lund University, Lund, Sweden,.
| | | | - Lisbeth E Knudsen
- Department of Public Health, Faculty Of Health Sciences, University of Copenhagen, Denmark.
| | - Udo R Markert
- Placenta-Labor Laboratory, Department of Obstetrics, Friedrich Schiller University, D-07740, Jena, Germany.
| | - Nicola Powles-Glover
- Reproductive, Development and Paediatric Centre of Excellence, AstraZeneca, Mereside, Alderley Park, Alderley Edge SK10 4TG, UK.
| | - Henning Schneider
- Department of Obstetrics and Gynecology, Inselspital, University of Bern, Switzerland.
| | - Lopa Leach
- Molecular Cell Biology & Development, School of Life Sciences, Faculty of Medicine & Health Sciences, University of Nottingham, UK.
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Abstract
This review examines the placental transport and metabolism of amino acids, with a special emphasis on unifying and interpreting in-vivo and in-vitro data. For a variety of technical reasons, in-vivo studies, which quantify placental amino-acid fluxes and metabolism, have been relatively limited, in comparison to in-vitro studies using various placental preparations. Following an introduction to placental amino-acid uptake and transfer to the fetus, the review attempts to reconcile in-vitro placental transport data with in-vivo placental data. Data are discussed with reference to the measured delivery rates of amino acids into the fetal circulation and the contribution of placental metabolism to this rate for many amino acids. The importance of exchange transporters in determining efflux from the placenta into the fetal circulation is presented with special reference to in-vivo studies of non-metabolizable and essential amino acids. The data which illustrate the interconversion and nitrogen exchange of three groups of amino acids, glutamine-glutamate, BCAAs and serine-glycine, within the placenta are discussed in terms of the potential role such pathways may serve for other placenta functions. The review also presents comparisons of the sheep and human placentae in terms of their in-vivo amino-acid transport rates.
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Affiliation(s)
- F C Battaglia
- Perinatal Research Center, Department of Pediatrics, Division of Perinatal Medicine, University of Colorado Health Sciences Center, Denver, Colorado, 80045, USA.
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Abstract
The yolk sac plays an important role in fetal nutrition. Transport of amino acids by the rodent visceral yolk sac has been shown previously. We have demonstrated the presence of several amino acid transport proteins capable of the Na(+)-dependent transport of anionic amino acids within late gestation mouse visceral yolk sac and uterine epithelium. We speculate that these proteins may be involved in the efflux of glutamate from the fetal to the maternal circulations.
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Affiliation(s)
- D A Novak
- Department of Pediatrics, University of Florida College of Medicine, Gainesville, FL 32610-0296, USA
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Hahn T, Hartmann M, Blaschitz A, Skofitsch G, Graf R, Dohr G, Desoye G. Localisation of the high affinity facilitative glucose transporter protein GLUT 1 in the placenta of human, marmoset monkey (Callithrix jacchus) and rat at different developmental stages. Cell Tissue Res 1995; 280:49-57. [PMID: 7750136 DOI: 10.1007/bf00304510] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/26/2023]
Abstract
In the present study, the facilitative D-glucose transporter protein GLUT 1 was localised by immunohistochemistry in the placenta of human, marmoset (Callithrix jacchus) and rat at different developmental stages. A polyclonal antiserum against a 13-amino-acid peptide of the GLUT 1 carboxy terminus was used. It identified a protein of around 50 kDa molecular weight in immunoblotting of the placental tissues. GLUT 1 was located in the syncytiotrophoblast, in cytotrophoblast cells and in fetal endothelium. Similar staining patterns, except in human extravillous cytotrophoblast cells, were observed at all differentiation stages, despite differences in the internal placental architecture of the species. In the marmoset placenta, GLUT 1 was undetectable in endothelial cells of maternal vessels. In rat placentae, trophoblastic giant cells, epithelial cells of both visceral and parietal yolk sac, yolk sac vessels and the stratum spongiosum were stained. Reichert's membrane did not immunoreact. Preadsorption of the antiserum with a 13-amino-acid peptide resulted in the loss of immunoreactivity. The results suggest that GLUT 1 is a prominent isoform of glucose transporters in mammalian placentae. It is generally abundant in placental cell populations bordering on the maternal and fetal circulations and may therefore facilitate an effective glucose supply to the fetus and placenta.
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Affiliation(s)
- T Hahn
- Geburtshilflich-Gynäkologische Universitätsklinik, Karl-Franzens-Universität Graz, Austria
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Carter AM, Detmer A, Teusch L. The rate of blood flow through the inverted yolk sac placenta of the anesthetized guinea-pig. Placenta 1993; 14:41-9. [PMID: 8456088 DOI: 10.1016/s0143-4004(05)80247-4] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/30/2023]
Abstract
The rate of blood flow through the yolk sac placenta of late gestation guinea-pig fetuses was estimated by an indirect approach: radionuclide-labelled microspheres were injected in a saphenous vein and the ratio of radioactivity in the yolk sac to that in one of several reference organs was calculated. The ratio was then multiplied by a constant derived from separate experiments in which blood flows to the fetal abdominal organs and chorioallantoic placenta were determined. Stomach blood flow was positively correlated to arterial oxygen content (r = 0.74, P < 0.05), as was the weight-specific splenic blood flow (r = 0.66, P < 0.05). Perfusion of the small and large bowel, kidneys and chorioallantoic placenta was not related to arterial pH or oxygen content and these organs were used as references for the estimation of vitelline blood flow. A positive correlation was found between yolk sac blood flow and arterial oxygen content (r = 0.91, P < 0.01). In normoxaemic guinea-pig fetuses, yolk sac blood flow is 100-300 microliters per min.
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Affiliation(s)
- A M Carter
- Department of Physiology, University of Odense, Denmark
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