Plasma amino acids in pregnancy, placental intervillous space and preterm newborn infants

Camelo, Jr Js; Martinez, F. E.; Gonçalves, Arthur Lopes; Monteiro, J; Jorge, Salim Moysés

doi:10.1590/s0100-879x2006005000103

Cited by 9 publications

(7 citation statements)

References 30 publications

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“…This is important, as the behavioural consequences of a 5-HT dysfunction in mother can reflect negatively on newborn developmental health. Despite the decrease in total [Trp] in late pregnancy, the total [Trp]/[CAA] ratio is either normal [37] or slightly decreased [38], because [CAA] are also decreased, presumably as a result of increased placental extraction of amino acids [55]. As free [Trp] is elevated in pregnancy, the free [Trp]/[CAA] ratio can be assumed to be increased.…”

Section: Importance Of Tryptophan and Its Utilization For A Successfumentioning

confidence: 99%

Tryptophan metabolism, disposition and utilization in pregnancy

2015

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SynopsisTryptophan (Trp) requirements in pregnancy are several-fold: (1) the need for increased protein synthesis by mother and for fetal growth and development; (2) serotonin (5-HT) for signalling pathways; (3) kynurenic acid (KA) for neuronal protection; (4) quinolinic acid (QA) for NAD + synthesis (5) other kynurenines (Ks) for suppressing fetal rejection. These goals could not be achieved if maternal plasma [Trp] is depleted. Although plasma total (free + albuminbound) Trp is decreased in pregnancy, free Trp is elevated. The above requirements are best expressed in terms of a Trp utilization concept. Briefly, Trp is utilized as follows: (1) In early and mid-pregnancy, emphasis is on increased maternal Trp availability to meet the demand for protein synthesis and fetal development, most probably mediated by maternal liver Trp 2,3-dioxygenase (TDO) inhibition by progesterone and oestrogens. (2) In mid-and late pregnancy, Trp availability is maintained and enhanced by the release of albumin-bound Trp by albumin depletion and non-esterified fatty acid (NEFA) elevation, leading to increased flux of Trp down the K pathway to elevate immunosuppressive Ks. An excessive release of free Trp could undermine pregnancy by abolishing T-cell suppression by Ks. Detailed assessment of parameters of Trp metabolism and disposition and related measures (free and total Trp, albumin, NEFA, K and its metabolites and pro-and anti-inflammatory cytokines in maternal blood and, where appropriate, placental and fetal material) in normal and abnormal pregnancies may establish missing gaps in our knowledge of the Trp status in pregnancy and help identify appropriate intervention strategies.

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Section: Importance Of Tryptophan and Its Utilization For A Successfumentioning

confidence: 99%

Tryptophan metabolism, disposition and utilization in pregnancy

2015

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“…Although net transfer of amino acids is in the maternal to foetal direction, some amino acids could be transported in the foetal to maternal direction and there is evidence for this in guinea pigs (22). This could potentially occur in humans, as a recent study suggests that the amino acid concentration in the human placental intervillous space may be higher than systemic maternal blood (23). Some amino acids taken up by the placenta may therefore be returned to the maternal circulation rather than transferred to the foetus.…”

Section: Placental Amino Acid Transfermentioning

confidence: 99%

The Mechanisms and Regulation of Placental Amino Acid Transport to the Human Foetus

Cleal

Lewis

2008

J Neuroendocrinology

128

114

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The mechanisms by which amino acids are transferred across the human placenta are fundamental to our understanding of foetal nutrition. Amino acid transfer across the human placenta is dependent on transport across both the microvillous and basal plasma membranes of the placental syncytiotrophoblast, and on metabolism within the syncytiotrophoblast. Although the principles underlying uptake of amino acids across the microvillous plasma membrane are well understood, the extent to which amino acids are metabolised within human placenta and the mechanisms by which amino acids are transported out of the placenta across the basal plasma membrane are not well understood. Understanding the mechanisms and regulation of amino acid transport is necessary to understand the causes of intrauterine growth restriction in human pregnancy.

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“…Accordingly, the rate of materno-foetal amino acid transfer, which can be assessed with techniques exploiting the infusion of stable-isotope-labelled amino acids, is reduced in IUGR infants, compared with control babies [10] and the drop in the materno-foetal isotope enrichment ratio depends on the severity of IUGR [11]. Amino acid transfer was also found to be affected by prematurity [12], maternal diabetes [13] or hypoxia [14].…”

Section: Introductionmentioning

confidence: 99%

1H-NMR-Based Metabolic Profiling of Maternal and Umbilical Cord Blood Indicates Altered Materno-Foetal Nutrient Exchange in Preterm Infants

et al. 2012

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BackgroundAdequate foetal growth is primarily determined by nutrient availability, which is dependent on placental nutrient transport and foetal metabolism. We have used 1H nuclear magnetic resonance (NMR) spectroscopy to probe the metabolic adaptations associated with premature birth.MethodologyThe metabolic profile in 1H NMR spectra of plasma taken immediately after birth from umbilical vein, umbilical artery and maternal blood were recorded for mothers delivering very-low-birth-weight (VLBW) or normo-ponderal full-term (FT) neonates.Principal FindingsClear distinctions between maternal and cord plasma of all samples were observed by principal component analysis (PCA). Levels of amino acids, glucose, and albumin-lysyl in cord plasma exceeded those in maternal plasma, whereas lipoproteins (notably low-density lipoprotein (LDL) and very low-density lipoprotein (VLDL) and lipid levels were lower in cord plasma from both VLBW and FT neonates. The metabolic signature of mothers delivering VLBW infants included decreased levels of acetate and increased levels of lipids, pyruvate, glutamine, valine and threonine. Decreased levels of lipoproteins glucose, pyruvate and albumin-lysyl and increased levels of glutamine were characteristic of cord blood (both arterial and venous) from VLBW infants, along with a decrease in levels of several amino acids in arterial cord blood.ConclusionThese results show that, because of its characteristics and simple non-invasive mode of collection, cord plasma is particularly suited for metabolomic analysis even in VLBW infants and provides new insights into the materno-foetal nutrient exchange in preterm infants.

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Plasma amino acids in pregnancy, placental intervillous space and preterm newborn infants

Cited by 9 publications

References 30 publications

Tryptophan metabolism, disposition and utilization in pregnancy

Tryptophan metabolism, disposition and utilization in pregnancy

The Mechanisms and Regulation of Placental Amino Acid Transport to the Human Foetus

1H-NMR-Based Metabolic Profiling of Maternal and Umbilical Cord Blood Indicates Altered Materno-Foetal Nutrient Exchange in Preterm Infants

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