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Partitioning of glutamine synthesised by the isolated perfused human placenta between the maternal and fetal circulations

Partitioning of glutamine synthesised by the isolated perfused human placenta between the maternal and fetal circulations
Partitioning of glutamine synthesised by the isolated perfused human placenta between the maternal and fetal circulations
Introduction: placental glutamine synthesis has been demonstrated in animals and is thought to increase the availability of this metabolically important amino acid to the fetus. Glutamine is of fundamental importance for cellular replication, cellular function and inter-organ nitrogen transfer. The objective of this study was to investigate the role of glutamate/glutamine metabolism by the isolated perfused human placenta in the provision of glutamine to the fetus.

Methods: glutamate metabolism was investigated in the isolated dually perfused human placental cotyledon. U–13C-glutamate was used to investigate the movement of carbon and 15N-leucine to study movement of amino-nitrogen. Labelled amino acids were perfused via maternal or fetal arteries at defined flow rates. The enrichment and concentration of amino acids in the maternal and fetal veins were measured following 5 h of perfusion.

Results: glutamate taken up from the maternal and fetal circulations was primarily converted into glutamine the majority of which was released into the maternal circulation. The glutamine transporter SNAT5 was localised to the maternal-facing membrane of the syncytiotrophoblast. Enrichment of 13C or 15N glutamine in placental tissue was lower than in either the maternal or fetal circulation, suggesting metabolic compartmentalisation within the syncytiotrophoblast.

Discussion: placental glutamine synthesis may help ensure the placenta's ability to supply this amino acid to the fetus does not become limiting to fetal growth. Glutamine synthesis may also influence placental transport of other amino acids, metabolism, nitrogen flux and cellular regulation.

Conclusions: placental glutamine synthesis may therefore be a central mechanism in ensuring that the human fetus receives adequate nutrition and is able to maintain growth
0143-4004
1223-1231
Day, P.E.L.
c5db77dc-3829-43ed-ba46-ece124d323d3
Cleal, J.K.
18cfd2c1-bd86-4a13-b38f-c321af56da66
Lofthouse, E.M.
c4004ff1-2ed3-4b80-9ade-583c742de59c
Goss, V.
b51e044d-48fa-414c-bea9-a58d2b15eeff
Koster, G.
c757aa1a-f456-4159-9332-a57caa1c35a7
Postle, A.
148d05d5-09e6-4582-8253-fdce60cc18ab
Jackson, J.M.
56d28442-62b1-4425-96c6-27c321dfd310
Hanson, M.A.
1952fad1-abc7-4284-a0bc-a7eb31f70a3f
Jackson, A.A.
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Lewis, R.M.
caaeb97d-ea69-4f7b-8adb-5fa25e2d3502
Day, P.E.L.
c5db77dc-3829-43ed-ba46-ece124d323d3
Cleal, J.K.
18cfd2c1-bd86-4a13-b38f-c321af56da66
Lofthouse, E.M.
c4004ff1-2ed3-4b80-9ade-583c742de59c
Goss, V.
b51e044d-48fa-414c-bea9-a58d2b15eeff
Koster, G.
c757aa1a-f456-4159-9332-a57caa1c35a7
Postle, A.
148d05d5-09e6-4582-8253-fdce60cc18ab
Jackson, J.M.
56d28442-62b1-4425-96c6-27c321dfd310
Hanson, M.A.
1952fad1-abc7-4284-a0bc-a7eb31f70a3f
Jackson, A.A.
44d1b003-3ee2-42e0-b83c-ab34b623a30b
Lewis, R.M.
caaeb97d-ea69-4f7b-8adb-5fa25e2d3502

Day, P.E.L., Cleal, J.K., Lofthouse, E.M., Goss, V., Koster, G., Postle, A., Jackson, J.M., Hanson, M.A., Jackson, A.A. and Lewis, R.M. (2013) Partitioning of glutamine synthesised by the isolated perfused human placenta between the maternal and fetal circulations. Placenta, 34 (12), 1223-1231. (doi:10.1016/j.placenta.2013.10.003). (PMID:24183194)

Record type: Article

Abstract

Introduction: placental glutamine synthesis has been demonstrated in animals and is thought to increase the availability of this metabolically important amino acid to the fetus. Glutamine is of fundamental importance for cellular replication, cellular function and inter-organ nitrogen transfer. The objective of this study was to investigate the role of glutamate/glutamine metabolism by the isolated perfused human placenta in the provision of glutamine to the fetus.

Methods: glutamate metabolism was investigated in the isolated dually perfused human placental cotyledon. U–13C-glutamate was used to investigate the movement of carbon and 15N-leucine to study movement of amino-nitrogen. Labelled amino acids were perfused via maternal or fetal arteries at defined flow rates. The enrichment and concentration of amino acids in the maternal and fetal veins were measured following 5 h of perfusion.

Results: glutamate taken up from the maternal and fetal circulations was primarily converted into glutamine the majority of which was released into the maternal circulation. The glutamine transporter SNAT5 was localised to the maternal-facing membrane of the syncytiotrophoblast. Enrichment of 13C or 15N glutamine in placental tissue was lower than in either the maternal or fetal circulation, suggesting metabolic compartmentalisation within the syncytiotrophoblast.

Discussion: placental glutamine synthesis may help ensure the placenta's ability to supply this amino acid to the fetus does not become limiting to fetal growth. Glutamine synthesis may also influence placental transport of other amino acids, metabolism, nitrogen flux and cellular regulation.

Conclusions: placental glutamine synthesis may therefore be a central mechanism in ensuring that the human fetus receives adequate nutrition and is able to maintain growth

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e-pub ahead of print date: 23 October 2013
Published date: December 2013
Organisations: Faculty of Medicine

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Local EPrints ID: 359574
URI: http://eprints.soton.ac.uk/id/eprint/359574
ISSN: 0143-4004
PURE UUID: 1d81f88f-59fb-4cc5-9141-6f67b4033026
ORCID for J.K. Cleal: ORCID iD orcid.org/0000-0001-7978-4327
ORCID for E.M. Lofthouse: ORCID iD orcid.org/0000-0002-0175-5590
ORCID for M.A. Hanson: ORCID iD orcid.org/0000-0002-6907-613X
ORCID for R.M. Lewis: ORCID iD orcid.org/0000-0003-4044-9104

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Date deposited: 05 Nov 2013 09:59
Last modified: 18 Feb 2021 17:20

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Contributors

Author: P.E.L. Day
Author: J.K. Cleal ORCID iD
Author: E.M. Lofthouse ORCID iD
Author: V. Goss
Author: G. Koster
Author: A. Postle
Author: J.M. Jackson
Author: M.A. Hanson ORCID iD
Author: A.A. Jackson
Author: R.M. Lewis ORCID iD

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