Maternal concentrations and fetal-maternal concentration differences of plasma amino acids in normal and intrauterine growth-restricted pregnancies

Cetin, Irene; Ronzoni, Stefania; Marconi, Anna Maria; Perugino, Giuseppe; Corbetta, Carlo; Battaglia, Frederick C.; Pardi, Giorgio

doi:10.1016/s0002-9378(96)70609-9

Cited by 161 publications

(115 citation statements)

References 16 publications

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“…As regards the former, Steel, Smith & Kelley (1982) showed that the uptake of AIB by placental tissue is inversely related to the intracellular concentration of amino acid. Since plasma concentrations of amino acids in the woman delivering a growthretarded baby are higher than normal (Cetin et al 1996) and if, as in the sheep (Owens et al 1989), extraction of amino acids by the small fetus from the placenta is reduced, then there might well be an increase in intracellular amino acids in the syncytiotrophoblast, which could cause reduced activity of system A by the 'transinhibition' phenomenon.…”

Section: Amino Acid Transfer and Fetal Growthmentioning

confidence: 99%

Placental transporter activity and expression in relation to fetal growth

Sibley¹,

Glazier²,

D'Souza³

1997

Experimental Physiology

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SUMMARYThe question of whether there are causative or compensatory changes in placental transport physiology affecting fetal growth is considered. Reductions in uterine and umbilical blood flow in growth retardation will reduce maternofetal exchange of lipophilic solutes, such as 02 and CO2, but will not have a major effect on the transfer of hydrophilic solutes. These solutes are transferred across the placenta by paracellular diffusion, transporter protein-mediated transport and endocytosis-exocytosis. Neither paracellular diffusion nor endocytosis-exocytosis has been investigated in relation to fetal growth. The weight of evidence is that there is no change in the activity and expression of the syncytiotrophoblast GLUT1 glucose transporter in fetal growth retardation. However, there is strong evidence that the activity of the system A amino acid transporter, per milligram of placental membrane protein, is altered in relation to fetal growth, but in a complex manner. There is also some weaker evidence that the activity of the Na+-H+ exchanger, per milligram of placental membrane protein, is directly related to birth-weight. There are no data for other solute transporters; a considerable amount of work still remains to be done in order to understand the relationship between placental function and fetal growth rate.

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Section: Amino Acid Transfer and Fetal Growthmentioning

confidence: 99%

Placental transporter activity and expression in relation to fetal growth

Sibley¹,

Glazier²,

D'Souza³

1997

Experimental Physiology

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“…In FGR, the maternal concentrations of most essential amino acids are significantly higher than in appropriate-for-gestational-age pregnancies, closer to fetal concentrations. This observation, coupled with lower fetal amino acid concentrations in FGR, trending towards maternal concentrations, leads to significantly lower fetalematernal differences [13]. These significantly lower fetalematernal concentration differences occur independently of the degree of severity [13].…”

Section: Human Infusion Studies -Differences In Certain Amino Acid Upmentioning

confidence: 95%

“…This observation, coupled with lower fetal amino acid concentrations in FGR, trending towards maternal concentrations, leads to significantly lower fetalematernal differences [13]. These significantly lower fetalematernal concentration differences occur independently of the degree of severity [13]. It has been of clinical interest to see if in human pregnancies complicated by FGR, the maternal intravenous infusion of amino acids can increase fetal amino acid concentrations and umbilical uptake.…”

Section: Human Infusion Studies -Differences In Certain Amino Acid Upmentioning

confidence: 99%

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

et al. 2005

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“…Plasma concentrations of most amino acids are higher in the foetus than in the mother, indicating an active transport of amino acids across the placenta against a concentration gradient (Cetin et al, 1996). In the growth restricted foetus, concentrations of total a-amino nitrogen are reduced, mainly due to reduced concentrations of the branched-chain amino acids (Cetin et al, 1990).…”

Section: Introductionmentioning

confidence: 99%

“…In the growth restricted foetus, concentrations of total a-amino nitrogen are reduced, mainly due to reduced concentrations of the branched-chain amino acids (Cetin et al, 1990). In addition, concentrations of many maternal amino acids are elevated in IUGR pregnancies, resulting in reduced foetalto-maternal concentration differences (Cetin et al, 1996). These changes in plasma amino acid concentrations are associated with a reduction in in vivo placental amino acid transport (Paolini et al, 2001).…”

Section: Introductionmentioning

confidence: 99%

Urea production and arginine metabolism are reduced in the growth restricted ovine foetus

Boo

Zijl

Lafeber

et al. 2007

Animal

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Urea production may be impaired in intrauterine growth restriction (IUGR), increasing the risk of toxic hyperammonaemia after birth. Arginine supplementation stimulates urea production, but its effects in IUGR are unknown. We aimed to determine the effects of IUGR and arginine supplementation on urea production and arginine metabolism in the ovine foetus. Pregnant ewes and their foetuses were catheterised at 110 days of gestation and randomly assigned to control or IUGR groups. IUGR was induced by placental embolisation. At days 120 and 126 of gestation, foetal urea production was determined from [ 14 C]-urea kinetics and arginine metabolism was determined from the appearance of radioactive metabolites from [ 3 H]-arginine, both at baseline and in response to arginine or an isonitrogenous mixed amino acid supplementation. Urea production decreased with gestational age in the embolised animals (13.9^3.1 to 11.2^3.0 mmol/kg per min, P # 0.05) but not in the controls (13.3^3.5 to 14.8^6.0 mmol/kg per min). Arginine supplementation increased urea production in both groups, but only at 126 days of gestation (control: 15.0^8.5 to 17.0^9.4 mmol/kg per min; embolised: 11.7^3.1 to 14.3^3.1 mmol/kg per min, P # 0.05). Embolisation reduced foetal arginine concentrations by 20% ( P # 0.05) while foetal arginine consumption was reduced by 27% ( P # 0.05). The proportions of plasma citrulline and hydroxyproline derived from arginine were reduced in the embolised animals. These data suggest that foetal urea production and arginine metabolism are perturbed in late gestation after placental embolisation.

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Maternal concentrations and fetal-maternal concentration differences of plasma amino acids in normal and intrauterine growth-restricted pregnancies

Cited by 161 publications

References 16 publications

Placental transporter activity and expression in relation to fetal growth

Placental transporter activity and expression in relation to fetal growth

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

Urea production and arginine metabolism are reduced in the growth restricted ovine foetus

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