Transport of Nutrients in the Early Human Placenta: Amino Acid, Creatine, Vitamin B12

Ng, Wendy W.; Miller, Richard K.

doi:10.1007/978-1-4684-1191-1_10

Cited by 8 publications

(3 citation statements)

References 20 publications

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“…Although the use of third-trimester placentae might be considered a potential limitation to our study, there is evidence to suggest that the qualitative aspects of transfer do not differ between placentae taken at earlier versus later phases of gestation (19).…”

Section: In Vivo Studiesmentioning

confidence: 94%

Transfer of Insulin Lispro Across the Human Placenta

et al. 2003

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OBJECTIVE—Insulin lispro (Humalog), a human insulin analog, has a more rapid onset, earlier peak, and shorter duration of glucose lowering activity than regular human insulin. However, it is not known whether insulin lispro crosses the human placenta and reaches the fetus. Therefore, the objective of the present study was to examine whether insulin lispro crosses the placenta using the technique of perfusing a human placental lobule in vitro. RESEARCH DESIGN AND METHODS—Term human placentae from uncomplicated pregnancies were obtained immediately after delivery. Insulin lispro, at concentrations ranging from 100 to 1000 μU/ml, was introduced into the maternal reservoir. The maternal side of the placenta was perfused with constant concentration of lispro insulin; the fetal circulation was closed. Samples were drawn from both the maternal and fetal circulations at regular intervals. The appearance of insulin lispro in the fetal circulation was analyzed by a specific radioimmunoassay. RESULTS—No placental transfer of lispro could be detected during perfusion with 100 and 200 μU/ml. In contrast, there was a small concentration-dependent transfer to the fetus at concentrations of 580 μU/ml and higher, detectable after at least an hour of constant concentration of insulin lispro during perfusion. The rate of placental transfer was 0.019 μU · min−1 · g tissue−1 at maternal levels of 580 μU/ml and 0.045 μU · min−1 · g−1 tissue at maternal levels of 1000 μU/ml. Measuring lispro levels in 11 pregnant women revealed that a dose of 50 units may achieve serum concentrations >200 μU/ml with apparent linear correlation between dose and levels. CONCLUSIONS—Insulin lispro is not likely to cross the placenta at a single standard dose. This study suggests that insulin lispro is unlikely to reach or harm the unborn baby.

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Section: In Vivo Studiesmentioning

confidence: 94%

Transfer of Insulin Lispro Across the Human Placenta

et al. 2003

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“…Placenta concentrates amino acids and placental amino acid levels usually greatly exceed both maternal and fetal sera levels (Montgomery and Young 1982). This placental accumulation is both stereospecific and energy dependent (Munro, Pilistine and Fant 1983;Ng and Miller 1983). Most amino acids are actively transported from the maternal serum across the brush-border membrane of the syncytiotrophoblast; these amino acids then passively diffuse across the fetal surface of the trophoblast (Kerr and Waisman 1966;Hill and Young 1973).…”

Section: Introductionmentioning

confidence: 99%

Distribution of Free Amino Acids in Streptozotocin-Induced Diabetic Pregnant Rats, Their Placentae and Fetuses

Copeland

Hendrich²,

Porterfield³

1990

Horm Metab Res

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Amino acid levels in the non-pregnant streptozotocin (STZ)-induced diabetic rat have been shown to be abnormal. Our preliminary studies showed that placental transport, fetal serum levels and tissue uptake of the non-metabolizable amino acid alpha-amino isobutyric acid (AIB) were decreased in STZ-diabetic pregnant rats. In the present experiments, amino acid concentrations were measured in maternal (MS) and fetal (FS) sera and placentae (PL) by high performance liquid chromatography (HPLC) after triple extraction in 80% ethanol. Control (C), STZ-diabetic (D) and insulin-treated diabetic (DI) animals were studied at 22 days gestation. Pregnant diabetic rats had low serum levels of Gln, Lys, and Ser and insulin treatment corrected Gln and Ser but not Lys levels. Branched-chain amino acids did not show the large elevation characteristic of the non-pregnant diabetic rat. Placental levels of Tau, Gln, HPr, Thr and Lys were depressed in the diabetic animals and insulin treatment only partially improved these amino acid profiles. Placental amino acid levels did not always reflect maternal serum levels. Serum levels of most amino acids were lower in the fetus of the diabetic rat than in the fetus of the control rat. The notable exception was Ala which was higher in the fetuses of the diabetic animals. Insulin treatment of the mother did not correct many of the fetal amino acid levels even though maternal and fetal serum glucose levels at the time of autopsy were normal. The ability to maintain normal serum levels of many amino acids is impaired in the fetus of the diabetic rat.(ABSTRACT TRUNCATED AT 250 WORDS)

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“…The mean umbilical arterial and venous Cr levels were above the reported plasma Cr reference values during pregnancy (35.6 µM ± 15.15) [26]. Based on human placenta slices' kinetics, maternal-fetal Cr transport has been hypothesized [41]. The Cr transporter (SLC6A8) has been shown to be expressed in human placental tissue, and term human placenta is also able to produce Cr and GAA [26,42].…”

Section: Umbilical Creatine Fluxmentioning

confidence: 91%

The Umbilical Cord Creatine Flux and Time Course of Human Milk Creatine across Lactation

Mihatsch,

Stahl,

Braun

2024

Nutrients

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(1) Background: The aim of the present paper was to study fetal and infant creatine (Cr) supply to improve nutrition and neuroprotection in term and especially in preterm infants. The primary outcomes were the placental Cr flux at the end of pregnancy and the time course of human milk (HM) Cr. (2) Methods: The estimation of placental Cr flux was based on umbilical arterial and venous cord blood Cr in 10 term infants after elective caesarian section. HM Cr, creatinine (Crn), and macronutrients were measured longitudinally in 10 mothers across the first 6 months of breastfeeding. (3) Results: At the end of pregnancy, the mean fetal Cr flux was negative (−2.07 mmol/min). HM Cr was highest in colostrum, decreased significantly within the first 2 weeks of breastfeeding (p < 0.05), and did not change significantly thereafter. HM Cr was not correlated with HM Crn or macronutrient composition. (4) Conclusions: The present data suggest that fetal endogenous Cr synthesis covers the needs at the end of pregnancy. However, high colostrum Cr and HM Cr levels, independent of macronutrient composition, suggest that there may be a critical Cr demand immediately after birth that needs to be covered by enteral supply.

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Transport of Nutrients in the Early Human Placenta: Amino Acid, Creatine, Vitamin B12

Cited by 8 publications

References 20 publications

Transfer of Insulin Lispro Across the Human Placenta

Transfer of Insulin Lispro Across the Human Placenta

Distribution of Free Amino Acids in Streptozotocin-Induced Diabetic Pregnant Rats, Their Placentae and Fetuses

The Umbilical Cord Creatine Flux and Time Course of Human Milk Creatine across Lactation

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