Adaptation of <i>in vivo</i> amino acid kinetics facilitates increased amino acid availability for fetal growth in adolescent and adult pregnancies alike

Thame, M; Hsu, Jean W.; Gibson, Raquel; Baker, Tameka M.; Tang, Grace J.; Badaloo, Asha; Fletcher, Horace; Jackson, Alan A.; Jahoor, Farook

doi:10.1017/s000711451400292x

Cited by 7 publications

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“…The authors suggested that the lower serine kinetics in late pregnancy may be part of a general down-regulation of α-amino N turnover related to a decreased rate of branchedchain amino acid transamination to facilitate N conservation and accretion. In agreement, in an earlier report of data from this project (11) , urea flux, an index of protein and amino acid catabolism, decreased from the first to the third trimester in both pregnant adolescent girls and adult women, indicating that they were conserving more N in the third trimester. However, leucine oxidation in the third trimester was similar to the first trimester, which does not support a decrease in branched-chain amino acid transamination in late pregnancy.…”

Section: Discussionsupporting

confidence: 92%

“…The maternal characteristics and pregnancy outcomes of the subjects have been published previously ( 11 ) . However, for convenience, some of the relevant data are presented in Table 1.…”

Section: Resultsmentioning

confidence: 99%

“…The objective of the present study was to measure and compare glycine and serine kinetics of pregnant adolescent girls and adult women in the first and third trimesters. The present study is part of the phase 2 study of a larger study of amino acid metabolism in pregnancy ( 11 ) .…”

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confidence: 99%

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Unlike pregnant adult women, pregnant adolescent girls cannot maintain glycine flux during late pregnancy because of decreased synthesis from serine

et al. 2016

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During pregnancy, glycine and serine become more important because they are the primary suppliers of methyl groups for the synthesis of fetal DNA, and more glycine is required for fetal collagen synthesis as pregnancy progresses. In an earlier study, we reported that glycine flux decreased by 39 % from the first to the third trimester in pregnant adolescent girls. As serine is a primary precursor for glycine synthesis, the objective of this study was to measure and compare glycine and serine fluxes and inter-conversions in pregnant adolescent girls and adult women in the first and third trimesters. Measurements were made after an overnight fast by continuous intravenous infusions of 2 H 2 -glycine and 15 N-serine in eleven adolescent girls (17·4 (SE 0·1) years of age) and in ten adult women (25·8 (SE 0·5) years of age) for 4 h. Adolescent girls had significantly slower glycine flux and they made less glycine from serine in the third (P < 0·05) than in the first trimester. Baby birth length was significantly shorter of adolescent girls (P = 0·04) and was significantly associated with third trimester glycine flux. These findings suggest that the pregnant adolescent cannot maintain glycine flux in late pregnancy compared with early pregnancy because of decreased synthesis from serine. It is possible that the inability to maintain glycine synthesis makes her fetus vulnerable to impaired cartilage synthesis, and thus linear growth.Key words: Pregnant adolescent girls: Pregnant adult women: Glycine: Serine Pregnancy during adolescence in Jamaica and elsewhere is associated with a high prevalence of low birth weight (1,2) . It has been proposed that this is due to an inability of the adolescent mother to provide the nutrient needs for her own growth and the growth of her fetus. In particular, the requirement for amino acids increases as pregnancy progresses in order to sustain increased rates of protein deposition (3) and to support increased availability of glucose through gluconeogenesis (4) .Dispensable amino acids comprise the bulk of maternal amino acids transferred to the fetus in pregnancy (5) . A good example is glycine, which is a provider of methyl groups needed for the synthesis of DNA necessary for cell division to support maternal and fetal tissue deposition (6,7) . In addition, most of fetal cartilage is synthesised during late pregnancy and glycine constitutes 25 % of the amino acids in cartilage (8) . Therefore, as pregnancy progresses, there is a higher fetal demand for glycine. From our earlier study, glycine flux decreased by 39 % from the first trimester to the third trimester in pregnant adolescent girls (9) . Plasma glycine concentration in pregnant adolescent girls also decreased significantly from trimester 1 to 3, indicating a reduced availability. These findings suggested that after an overnight fast pregnant adolescent girls had a shortage in glycine supply in late pregnancy because they could not maintain production similar to their adult counterparts. However, de novo synthesis of g...

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Section: Discussionsupporting

confidence: 92%

“…The maternal characteristics and pregnancy outcomes of the subjects have been published previously ( 11 ) . However, for convenience, some of the relevant data are presented in Table 1.…”

Section: Resultsmentioning

confidence: 99%

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Unlike pregnant adult women, pregnant adolescent girls cannot maintain glycine flux during late pregnancy because of decreased synthesis from serine

et al. 2016

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“…For example, amino acid kinetics studies suggest that adolescents may be less able than older women to increase their circulating amino acid concentration through synthesis and/or protein breakdown in response to pregnancy. 22,23 This could reduce the availability of the amino acids to the fetus, especially in late pregnancy when requirements are greatest to support rapid fetal growth. This mechanism does not explain the findings in early pregnancy when fetal nutrient requirements are small.…”

Section: Discussionmentioning

confidence: 99%

The Association of Maternal Age With Fetal Growth and Newborn Measures: The Mumbai Maternal Nutrition Project (MMNP)

et al. 2019

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Background: Young maternal age is associated with poorer birth outcomes, but the mechanisms are incompletely understood. Using data from a prospective cohort of pregnant women living in Mumbai slums, India, we tested whether lower maternal age was associated with adverse fetal growth. Methods: Fetal crown-rump length (CRL) was recorded at a median (interquartile range, IQR) of 10 weeks’ gestation (9-10 weeks). Head circumference (HC), biparietal diameter (BPD), femur length (FL), and abdominal circumference (AC) were recorded at 19 (19-20) and 29 (28-30) weeks. Newborns were measured at a median (IQR) of 2 days (1-3 days) from delivery. Gestation was assessed using prospectively collected menstrual period dates. Results: The sample comprised 1653 singleton fetuses without major congenital abnormalities, of whom 1360 had newborn measurements. Fetuses of younger mothers had smaller CRL (0.01 standard deviation [SD] per year of maternal age; 95% confidence interval CI: 0.00-0.02 1 ; P = .04), and smaller HC, FL, and AC at subsequent visits. Fetal growth of HC (0.04 cm; 95% CI: 0.02-0.05; P < .001), BPD (0.01 cm; 95% CI: 0.00-0.01; P = .009), FL (0.04 cm; 95% CI: 0.02-0.06; P < .001), and AC (0.01 cm; 95% CI: 0.00-0.01; P = .003) up to the third trimester increased with maternal age. Skinfolds, head, and mid-upper arm circumferences were smaller in newborns of younger mothers. Adjusting for maternal prepregnancy socioeconomic status, body mass index, height, and parity attenuated the associations between maternal age and newborn size but did not change those with fetal biometry. Conclusion: Fetuses of younger mothers were smaller from the first trimester onward and grew slower, independently of known confounding factors.

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“…Важную роль в биохимических процессах организма человека занимают аминокислоты [4][5][6]15]. Возрастание роли аминокислот при беременности связано с повышенной потребностью белка для обеспечения материнских тканей и роста плода, необходимостью поддержания доступности глюкозы -основного топлива для растущего плода [14], а также участием их в регуляторно-метаболических процессах, направленных на обеспечение роста и нормальных физиологических функций плода [13]. Содержание аминокислот в сыворотке крови матери изменяется при развитии осложнений беременности, характер изменений определяется патологией [7][8][9], поэтому исследование метаболического профиля биологических жидкостей и выявление его особенностей у беременных женщин, имеющих нарушения гестационного процесса, является важным для разработки новых эффективных подходов к раннему прогнозированию осложнений и более глубокому пониманию их патогенеза [9].…”

Section: Introductionunclassified

Possibilities for prediction of congenital fetal malformations and chromosomal abnormalities based on the determination of the levels of free amino acids and their nitrogen-containing derivatives in blood plasma of pregnant women

Keda

Наумов

Smirnov

2020

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Objective: to determine the possibilities for prediction and diagnosis of congenital fetal malformations and chromosomal abnormalities on the basis of the study of the levels of amino acids and their nitrogen-containing derivatives in blood plasma of pregnant women with pathological conditions requiring artificial termination of pregnancy. Material and methods. The content of free amino acids and their nitrogen-containing derivatives was studied in 104 pregnant women having congenital malformations and chromosomal abnormalities in their fetuses at 13-22 weeks` gestation (group I) and 25 women with physiological pregnancy (group II). The amino acid level was determined by the high-performance liquid chromatography method. Results. The levels of 14 out of the 26 studied amino acids in the blood plasma of the pregnant women of group I were statistically higher than those of the women in group II. ROC analysis was used to determine six amino acids (glycine, α-aminobutyric acid, hydroxylysine, glutamic acid, citrulline, serine) and their threshold values which with high accuracy (85.3 %) allow of predicting congenital fetal malformations and chromosomal abnormalities. A prognostic model making it possible to determine high probability of congenital fetal anomalies based on the determination of the concentration of 5-hydroxytryptophan, glycine, asparagine, and serine in blood plasma of pregnant women has been developed. Conclusion. The study of the levels of amino acids and their nitrogen-containing derivatives in plasma of pregnant women at 13-22 weeks` gestation can be used for prenatal diagnosis of congenital fetal malformations and chromosomal abnormalities, as well as used as an additional criterion for making the decision on the necessity for artificial termination of pregnancy upon fetal medical indications.

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Adaptation of in vivo amino acid kinetics facilitates increased amino acid availability for fetal growth in adolescent and adult pregnancies alike

Cited by 7 publications

References 30 publications

Unlike pregnant adult women, pregnant adolescent girls cannot maintain glycine flux during late pregnancy because of decreased synthesis from serine

Unlike pregnant adult women, pregnant adolescent girls cannot maintain glycine flux during late pregnancy because of decreased synthesis from serine

The Association of Maternal Age With Fetal Growth and Newborn Measures: The Mumbai Maternal Nutrition Project (MMNP)

Possibilities for prediction of congenital fetal malformations and chromosomal abnormalities based on the determination of the levels of free amino acids and their nitrogen-containing derivatives in blood plasma of pregnant women

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