Human fetal albumin synthesis rates during different periods of gestation

Akker, Chris H.P. van den; Schierbeek, Henk; Rietveld, Trinet; Vermes, András; Duvekot, Johannes J.; Steegers, Eric A.P.; Goudoever, Johannes B. van

doi:10.1093/ajcn/88.4.997

Cited by 47 publications

(24 citation statements)

References 40 publications

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“…This report is the third in a series exploring fetal amino acid and protein metabolism by our group (4,5). In this study, several metabolic pathways of the essential amino acids leucine, valine, and methionine were quantified.…”

Section: Discussionmentioning

confidence: 98%

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Amino Acid Metabolism in the Human Fetus at Term: Leucine, Valine, and Methionine Kinetics

et al. 2011

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Human fetal metabolism is largely unexplored. Understanding how a healthy fetus achieves its fast growth rates could eventually play a pivotal role in improving future nutritional strategies for premature infants. To quantify specific fetal amino acid kinetics, eight healthy pregnant women received before elective cesarean section at term, continuous stable isotope infusions of the essential amino acids [1-13 C, 15 N]leucine, [U-13 C 5 ]valine, and [1-13 C]methionine. Umbilical blood was collected after birth and analyzed for enrichments and concentrations using mass spectrometry techniques. Fetuses showed considerable leucine, valine, and methionine uptake and high turnover rates. ␣-Ketoisocaproate, but not ␣-ketoisovalerate (the leucine and valine ketoacids, respectively), was transported at net rate from the fetus to the placenta. Especially, leucine and valine data suggested high oxidation rates, up to half of net uptake. This was supported by relatively low ␣-ketoisocaproate reamination rates to leucine. Our data suggest high protein breakdown and synthesis rates, comparable with, or even slightly higher than in premature infants. The relatively large uptakes of total leucine and valine carbon also suggest high fetal oxidation rates of these essential branched chain amino acids. (Pediatr Res 70: 566-571, 2011) H istorical wise, the fact that the design of current nutrition for premature neonates is merely step-by-step alterations of the original composition of breast milk (1) is not surprising. Years ago, gestational viability was closer to term than it is currently, and the analysis of normal neonatal nutrition was easier than the study of fetal nutrition. But with increased survival of less mature infants, metabolic demands of these young individuals probably deviate much more from those who receive breast milk or regular formula after term birth. Besides, we know from several decades of animal fetal research that intrauterine nutrient supply delivers more amino acids and less fat than is supplied during breast feeding (2). Today, however, the exact composition of human fetal nutrient supply still remains unknown.With the availability of harmless tracer studies, human fetal metabolism can be unraveled (3-7). To add to the very scarce knowledge bank, our aim was to investigate several aspects of human fetal essential amino acid metabolism. In this study, we were interested in fetal kinetics of the branched chain amino acids (leucine and valine) and of another essential amino acid, methionine. Previously, fetal kinetics of phenylalanine and tyrosine were described. These two amino acids together with those studied here were chosen both scientifically as well as practically. First, they are often subject of debate when it comes to (parenteral) neonatal nutrition. Second, their stable isotopomers are affordable, and our laboratory has much experience analyzing them accurately. Metabolism was determined after the infusion of stable isotopically labeled amino acids into pregnant women undergoing ele...

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Section: Discussionmentioning

confidence: 98%

“…With the availability of harmless tracer studies, human fetal metabolism can be unraveled (3)(4)(5)(6)(7). To add to the very scarce knowledge bank, our aim was to investigate several aspects of human fetal essential amino acid metabolism.…”

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confidence: 99%

Amino Acid Metabolism in the Human Fetus at Term: Leucine, Valine, and Methionine Kinetics

et al. 2011

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“…We also found a positive association between GA levels of maternal and cord blood, as in a previous study (19), but the association was not as strong as that observed between maternal and cord 25OHD. Albumin was reported not to significantly pass through the placenta (20), but fetal liver can synthesize albumin at a high rate at two-thirds of gestation (21,22). These results suggest that glucose may be not only passively, but also actively, transferred from mother to fetus through the placenta through regulation by unknown factors.…”

Section: Discussionmentioning

confidence: 93%

Inverse association between maternal 25OHD level and cord GLP-1/GIP concentrations

et al. 2015

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Background: Because vitamin D may have beneficial effects on glucose metabolism in pregnant women with gestational diabetes mellitus, we explored whether maternal 25-hydroxyvitamin D (25OHD) levels in normal pregnancy have association with diabetes-related hormone levels and glycated albumin (GA). Methods: A prospective cohort study was performed to collect serum samples from 612 pairs of pregnant women and cord blood of their offspring. Levels of 25OHD and GA in maternal and cord blood were measured by radioimmunoassay and enzyme assay, respectively. Using cord serum, 12 diabetes-related hormones were assayed. Spearman's rank correlation coefficient was used to quantify the strength of association between biomarkers. results: A prominent association between maternal and cord 25OHD levels (r = 0.76, 95% confidence intervals (CIs): 0.73-0.79, P < 0.0001) and weak association between maternal and cord GA (r = 0.22, 95% CIs: 0.14-0.30, P < 0.0001) were shown. Among the 12 diabetes-related hormones, both maternal and cord 25OHD levels showed prominent negative associations with glucagon-like peptide 1 (GLP-1) and glucose-dependent insulinotropic polypeptide (GIP). conclusions: These results suggest that decreased maternal 25OHD may be associated with decreased cord 25OHD and increased cord GLP-1 and GIP levels, which may be involved with the transfer of maternal glucose to the fetus. INTRODUCTIONVitamin D is made primarily under the skin by exposure to sunlight and can be obtained to a lesser extent in foods such as mushrooms, oily fish, and egg yolks. Vitamin D is first hydroxylated in the liver to form 25-hydroxyvitamin D (25OHD), then a very small amount of 25OHD is activated in the kidney to play important roles in the body, including in bone integrity and calcium metabolism (1). Indeed, vitamin D supplementation with calcium can prevent bone fracture and bone loss in the elderly (2). In addition to calcium metabolism, vitamin D repletion for 12 wk not only increases serum vitamin D concentrations but also improves β-cell activity (3).Moreover, maternal vitamin D deficiency during pregnancy has been suggested to be associated with an increased risk of gestational diabetes mellitus (4,5). In fact, recent randomized, double-blind, placebo-controlled clinical trials have suggested that vitamin D supplementation can decrease fasting glucose as well as insulin levels in gestational diabetes (6,7), although the results have been inconsistent (8). In addition, associations between serum 25OHD and glucose levels in pregnant women without gestational diabetes remain unknown. Therefore, using a Bio-Plex MAGPIX Suspension Array System (Bio-Rad, Hercules, CA), we performed screening of cord blood for 12 well-known diabetes-related hormones: glucagon-like peptide 1 (GLP-1); glucose-dependent insulinotropic polypeptide (GIP); ghrelin; insulin; c-peptide; glucagon; leptin; plasminogen activator inhibitor-1 (PAI-1); resistin; visfatin; adipsin; and adiponectin. We then analyzed associations between levels of these hormones and ...

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“…After hydrolyzation with HCl, leucine was isolated and derivatized using ethyl chloroformate (ECF) [14]. Enrichments of leucine were then measured on a gas chromatograph combustion isotope ratio mass spectrometer (GC/C/IRMS; Delta XP; Thermo Electron, Bremen, Germany) as previously described [7,10]. The endogenous 13 C background levels were assumed to be equivalent for all infants.…”

Section: Methodsmentioning

confidence: 99%

“…The endogenous stimulation of albumin synthesis might be more effective. In fetal studies, albumin synthesis seems to be much lower in preterm neonates than in fetuses [7,8], presumably because of postnatal malnutrition or increased stress [9]. Because albumin synthesis rates have been shown to be responsive to parenteral nutrition [8,10,11], it can be speculated that endogenous synthesis can be increased by the optimized administration of amino acids and energy.…”

Section: Introductionmentioning

confidence: 99%

Albumin synthesis in very low birth weight infants is enhanced by early parenteral lipid and high-dose amino acid administration

et al. 2016

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Human fetal albumin synthesis rates during different periods of gestation

Cited by 47 publications

References 40 publications

Amino Acid Metabolism in the Human Fetus at Term: Leucine, Valine, and Methionine Kinetics

Amino Acid Metabolism in the Human Fetus at Term: Leucine, Valine, and Methionine Kinetics

Inverse association between maternal 25OHD level and cord GLP-1/GIP concentrations

Albumin synthesis in very low birth weight infants is enhanced by early parenteral lipid and high-dose amino acid administration

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