Umbilical amino acid concentrations in normal and growth-retarded fetuses sampled in utero by cordocentesis

Cetin, Irene; Corbetta, Carlo; Sereni, Lucia Piceni; Marconi, Anna Maria; Bozzetti, Patrizia; Pardi, Giorgio; Battaglia, Frederick C.

doi:10.1016/0002-9378(90)90860-a

Cited by 245 publications

(137 citation statements)

References 20 publications

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“…Therefore, rat placenta possesses at least three different alanine transport systems, while human possesses two [11]. The fetal/maternal ratio of serum alanine concentration in rats [3] is remarkably higher than that in human [5,6]. It Table 2.…”

Section: Discussionmentioning

confidence: 99%

“…In vitro study, the treatment with growth factors, such as epidermal growth factor (EGF) and insulin-like growth factor-I (IGF-I) resulted in fetal growth [3,8,10], increased amino acid uptake in cultured placental cells [15,18,21]. The serum levels of amino acid are known to be kept higher in the fetal side than those in maternal side in human [5] and also in rats [3], indicating an active transport across the placental microvillous membrane [14]. Kalkhoff et al [12] reported that maternal plasma proline level showed a significant correlation with neonatal birth weight in human.…”

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confidence: 99%

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Proline, Leucine, and Alanine Transport in Placental Microvillous Membrane Vesicles Prepared from Late Gestational Rats.

Bonkobara

Thongsong

Matsuki

et al. 1998

The Journal of Veterinary Medical Science

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ABSTRACT. To characterize the active transport of amino acids across the placenta, uptakes of proline, leucine, and alanine were kinetically examined in placental microvillous membrane vesicles (PMV) prepared from rats in the late gestational period. Uptake rates of these amino acids in PMV showed saturable hyperbolic curves that obeyed Michaelis-Menten kinetics. Proline, leucine, and alanine transport were demonstrated to be carrier mediated systems with sodium-dependent, -independent, and both manner, respectively. In addition, sodium-dependent L-alanine transport showed two different systems, and new sodium-independent alanine transport system (K m of 1.12 mM) was observed in rat placenta. From these results, rat placenta has carrier mediated amino acid transport systems, and posseses at least three different transport systems for alanine. -KEY WORDS: alanine, leucine, placental microvillous membrane vesicle (PMV), proline, transport.

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Section: Discussionmentioning

confidence: 99%

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confidence: 99%

Proline, Leucine, and Alanine Transport in Placental Microvillous Membrane Vesicles Prepared from Late Gestational Rats.

Bonkobara

Thongsong

Matsuki

et al. 1998

The Journal of Veterinary Medical Science

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“…However, these may not be the appropriate comparison infants for very preterm infants with the goal of achieving fetal in utero protein accretion rates. For this reason, we compared neonatal amino acid concentrations in the HAA group with those of second and third trimester human fetuses in which cordocentesis was performed (51). Results are shown in Figure 5.…”

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confidence: 99%

Effect of Low versus High Intravenous Amino Acid Intake on Very Low Birth Weight Infants in the Early Neonatal Period

Thureen

2003

Pediatric Research

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Greater protein intakes are required than have been commonly used to achieve fetal in utero protein accretion rates in preterm neonates. To study the efficacy and safety of more aggressive amino acid intake, we performed a prospective randomized study in 28 infants [mean wt, 946 Ϯ 40 g (SEM)] of 1 (low amino acid intake, LAA) versus 3 g·kg Ϫ1 ·d Ϫ1 (high amino acid intake, HAA) at 52.0 Ϯ 3.0 h of life. After a minimum of 12 h of parenteral nutrition, efficacy was determined by protein balance and was significantly lower in the LAA versus HAA groups by both nitrogen balance (Ϫ0. Abbreviations PN, parenteral nutrition LAA, low amino acid intake HAA, high amino acid intake Int leuc , leucine intake rate Q leuc , leucine flux rate Ox leuc , leucine oxidation rate NOD leuc , nonoxidative leucine disposal intake rate RP leuc , rate of leucine appearance from protein breakdown ELBW, extremely low birth weight BUN, blood urea nitrogen GCMS, gas chromatography-mass spectroscopyThe current standard for postnatal nutrition in all preterm infants is one that duplicates normal in utero fetal growth rates (1). Owing to advances in perinatal care, more very preterm infants are surviving. These infants have unique nutritional metabolic requirements for growth, predicted by low energy stores, high protein flux rate, and a high metabolic rate as a result of a relatively larger mass of metabolically active organs. Nevertheless, it is common practice in many neonatal intensive care units to limit nutrient administration, particularly amino acids, to ELBW or sick neonates in the early neonatal period because of concerns of substrate intolerance. Several studies suggest that this delay in nutrition results in postnatal malnutrition that produces measurable growth failure at hospital discharge (2-4).Although strategies to improve growth necessitate delivery of larger amounts of both energy and protein beginning shortly after birth, there are reasons to suggest that focusing on protein delivery may be particularly important. Throughout life, maximal weight-specific protein gain occurs before 32 wk gestation (5). Data from studies in fetal animal models suggest that amino acid metabolic rates may be a much more sensitive indicator than growth rate of adequate nutrition before term (6). Additionally, recent data suggest that long-term developmental outcome in the preterm may be correlated with early protein intake (7

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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). In addition, concentrations of many maternal amino acids are elevated in IUGR pregnancies, resulting in reduced foetalto-maternal concentration differences (Cetin et al, 1996).…”

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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Umbilical amino acid concentrations in normal and growth-retarded fetuses sampled in utero by cordocentesis

Cited by 245 publications

References 20 publications

Proline, Leucine, and Alanine Transport in Placental Microvillous Membrane Vesicles Prepared from Late Gestational Rats.

Proline, Leucine, and Alanine Transport in Placental Microvillous Membrane Vesicles Prepared from Late Gestational Rats.

Effect of Low versus High Intravenous Amino Acid Intake on Very Low Birth Weight Infants in the Early Neonatal Period

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

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