Placental amino acid transport systems and fetal growth restriction – A workshop report

Regnault, Timothy R. H.; Marconi, Anna Maria; Smith, Carl H.; Glazier, Jocelyn D.; Novak, Donald A.; Sibley, Colin P.; Jansson, Thomas

doi:10.1016/j.placenta.2005.02.006

Cited by 19 publications

(20 citation statements)

References 33 publications

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“…In severe IUGR fetal lambs (placental and fetal weights reduced by 40–60%), it has been shown that umbilical oxygen, glucose, and essential amino acid uptakes are significantly reduced compared to control animals whereas there are no differences in moderate IUGR (placental and fetal weights reduced by 25%) [44]. Two possible explanations have been proposed for these difference: first, since the placental diffusional exchange capacity of the severe IUGR fetus is significantly reduced, compared to AGA and moderate IUGR, changes in placental permeability and surface area might act as an impediment to control value uptakes per unit fetal weight; second, an upregulation of specific placental transport systems might be present since the mRNA expression of system L light chain components, LAT-1 and LAT-2, in severe IUGR is not different from control placentas, whereas it is significantly elevated in moderate IUGR [44].…”

Section: Intrauterine Growth Restrictionmentioning

confidence: 99%

“…Two possible explanations have been proposed for these difference: first, since the placental diffusional exchange capacity of the severe IUGR fetus is significantly reduced, compared to AGA and moderate IUGR, changes in placental permeability and surface area might act as an impediment to control value uptakes per unit fetal weight; second, an upregulation of specific placental transport systems might be present since the mRNA expression of system L light chain components, LAT-1 and LAT-2, in severe IUGR is not different from control placentas, whereas it is significantly elevated in moderate IUGR [44]. …”

Section: Intrauterine Growth Restrictionmentioning

confidence: 99%

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Placental Amino Acids Transport in Intrauterine Growth Restriction

Avagliano

Garò

Marconi

2012

Journal of Pregnancy

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The placenta represents a key organ for fetal growth as it acts as an interface between mother and fetus, regulating the fetal-maternal exchange of nutrients, gases, and waste products. During pregnancy, amino acids represent one of the major nutrients for fetal life, and both maternal and fetal concentrations are significantly different in pregnancies with intrauterine growth restriction when compared to uncomplicated pregnancies. The transport of amino acids across the placenta is a complex process that includes the influx of neutral, anionic, and cationic amino acids across the microvilluos plasma membrane of the syncytiotrophoblast, the passage through the cytoplasm of the trophoblasts, and the transfer outside the trophoblasts across the basal membrane into the fetal circulation. In this paper, we review the transport mechanisms of amino acids across the placenta in normal pregnancies and in pregnancies complicated by intrauterine growth restriction.

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Section: Intrauterine Growth Restrictionmentioning

confidence: 99%

Section: Intrauterine Growth Restrictionmentioning

confidence: 99%

Placental Amino Acids Transport in Intrauterine Growth Restriction

Avagliano

Garò

Marconi

2012

Journal of Pregnancy

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“…Polymorphisms of the glucokinase gene have been shown to affect maternal capacity to deliver nutrients to the fetus [10]. There may also be polymorphisms in placental transport systems [11]. Thus, the fetal supply line is based on a complex cascade that is not only influenced by genetic variation but is also very sensitive to environmental factors.…”

Section: Regulation Of Fetal Growth – An Adaptive Response?mentioning

confidence: 99%

The Consequences of Being Born Small – An Adaptive Perspective

Gluckman

Hanson

2006

Horm Res Paediatr

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Absolute definitions of fetal growth are being replaced by definitions that focus on an optimal life-course trajectory. The fetus makes responses to its environment that are determined by the maternal macro-environment, health and physiology. The processes of maternal constraint create significant variations within the normal range of maternal environments and function, and in the fetal environment, which are reflected in different patterns of growth. Deficient nutrient provision may induce immediate adaptation in the form of fetal growth impairment, but will also induce adaptive responses that have evolved for predictive advantage; that is, for a later phase of the life cycle. This latter class of response, probably mediated by epigenetic processes, explains many outcomes of a less-than-optimal pregnancy, including impaired growth, increased visceral obesity, impaired cognitive development, advanced maturation and a greater risk of metabolic and related disease in later life. While these adaptive processes evolved and were appropriate in the environments of prehistory, they are increasingly mismatched with modern environments. Such considerations suggest different approaches to intervention and prevention in population-specific contexts.

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“…(9; 10) Energy-dependent amino acid transporters are present on both the maternal-facing (apical) and fetal-facing (basal) surfaces of the trophoblast in the human placenta. Several different transport systems exist to transfer particular groups of amino acids based on their charge and structure.…”

Section: Amino Acid Transfer and Metabolismmentioning

confidence: 99%

“…Several different transport systems exist to transfer particular groups of amino acids based on their charge and structure. (9-11) For example, one of the amino acid transport systems can transfer all of the branched chain amino acids (BCAA, leucine, isoleucine and valine), threonine, tryptophan, phenylalanine, and methionine. Conversely an individual amino acid can be transferred by multiple systems.…”

Section: Amino Acid Transfer and Metabolismmentioning

confidence: 99%

Maternal amino acid supplementation for intrauterine growth restriction

Brown

Green

Limesand³

et al. 2011

Front Biosci

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Maternal dietary protein supplementation to improve fetal growth has been considered as an option to prevent or treat intrauterine growth restriction. However, in contrast to balanced dietary supplementation, adverse perinatal outcomes in pregnant women who received high amounts of dietary protein supplementation have been observed. The responsible mechanisms for these adverse outcomes are unknown. This review will discuss relevant human and animal data to provide the background necessary for the development of explanatory hypotheses and ultimately for the development therapeutic interventions during pregnancy to improve fetal growth. Relevant aspects of fetal amino acid metabolism during normal pregnancy and those pregnancies affected by IUGR will be discussed. In addition, data from animal experiments which have attempted to determine mechanisms to explain the adverse responses identified in the human trials will be presented. Finally, we will suggest new avenues for investigation into how amino acid supplementation might be used safely to treat and/or prevent IUGR.

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Placental amino acid transport systems and fetal growth restriction – A workshop report

Cited by 19 publications

References 33 publications

Placental Amino Acids Transport in Intrauterine Growth Restriction

Placental Amino Acids Transport in Intrauterine Growth Restriction

The Consequences of Being Born Small – An Adaptive Perspective

Maternal amino acid supplementation for intrauterine growth restriction

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