scholarly journals Decreased placental amino acid transport and intrauterine growth restriction: which is the chicken and which is the egg?

2006 ◽  
Vol 576 (3) ◽  
pp. 649-649 ◽  
Author(s):  
Peter W. Nathanielsz
Keyword(s):  
Amino Acid ◽  
Amino Acid Transport ◽  
Intrauterine Growth Restriction ◽  
Growth Restriction ◽  
Acid Transport ◽  
Intrauterine Growth

scholarly journals Reduction of In Vivo Placental Amino Acid Transport Precedes the Development of Intrauterine Growth Restriction in the Non-Human Primate

Nutrients ◽  
2021 ◽  
Vol 13 (8) ◽  
pp. 2892
Author(s):  
Fredrick J. Rosario ◽  
Anita Kramer ◽  
Cun Li ◽  
Henry L. Galan ◽  
Theresa L. Powell ◽  
...  
Keyword(s):  
Amino Acid ◽  
Amino Acid Transport ◽  
Intrauterine Growth Restriction ◽  
Growth Restriction ◽  
Acid Transport ◽  
Mole Percent ◽  
System A ◽  
System L ◽  
Human Primate

Intrauterine growth restriction (IUGR) is associated with reduced placental amino acid transport (AAT). However, it remains to be established if changes in AAT contribute to restricted fetal growth. We hypothesized that reduced in vivo placental AAT precedes the development of IUGR in baboons with maternal nutrient restriction (MNR). Baboons were fed either a control (ad libitum) or MNR diet (70% of control diet) from gestational day (GD) 30. At GD 140, in vivo transplacental AA transport was measured by infusing nine (13)C- or (2)H-labeled essential amino acids (EAAs) as a bolus into the maternal circulation at cesarean section. A fetal vein-to-maternal artery mole percent excess ratio for each EAA was measured. Microvillous plasma membrane (MVM) system A and system L transport activity were determined. Fetal and placental weights were not significantly different between MNR and control. In vivo, the fetal vein-to-maternal artery mole percent excess ratio was significantly decreased for tryptophan in MNR. MVM system A and system L activity was markedly reduced in MNR. Reduction of in vivo placental amino acid transport precedes fetal growth restriction in the non-human primate, suggesting that reduced placental amino acid transfer may contribute to IUGR.

scholarly journals N-Carbamylglutamate and l-Arginine Promote Intestinal Absorption of Amino Acids by Regulating the mTOR Signaling Pathway and Amino Acid and Peptide Transporters in Suckling Lambs with Intrauterine Growth Restriction

2019 ◽  
Vol 149 (6) ◽  
pp. 923-932 ◽  
Author(s):  
Hao Zhang ◽  
Along Peng ◽  
Yin Yu ◽  
Shuang Guo ◽  
Mengzhi Wang ◽  
...  
Keyword(s):  
Amino Acid ◽  
Signaling Pathway ◽  
Intrauterine Growth Restriction ◽  
Nutrient Absorption ◽  
Mtor Signaling ◽  
Growth Restriction ◽  
Peptide Transporter ◽  
Mtor Signaling Pathway ◽  
Intrauterine Growth ◽  
Peptide Transporters

ABSTRACT Background Previous studies have revealed that dietary N-carbamylglutamate (NCG) and l-arginine (Arg) improve intestinal integrity, oxidative state, and immune function in Hu suckling lambs with intrauterine growth restriction (IUGR). Whether these treatments alter intestinal nutrient absorption is unknown. Objective The aim of this study was to determine the influence of dietary NCG and Arg treatment during the suckling period on intestinal amino acid (AA) absorption, alterations in the mechanistic target of rapamycin (mTOR) signaling pathway, and the abundance of AA and peptide transporters in IUGR lambs. Methods On day 7 after birth, 48 newborn Hu lambs were selected from a cohort of 424 twin lambs. Normal-birth-weight and IUGR Hu lambs were allocated randomly (n = 12/group) to a control (4.09 ± 0.12 kg), IUGR (3.52 ± 0.09 kg), IUGR + 0.1% NCG (3.49 ± 0.11 kg), or IUGR + 1% Arg (3.53 ± 0.10 kg). Results At day 28, compared with the IUGR group, the IUGR groups receiving NCG and Arg had 7.4% and 7.2% greater (P < 0.05) body weight, respectively. Compared with the IUGR group, the serum concentration of insulin was greater (P < 0.05) and the cortisol was lower (P < 0.05) in the IUGR groups receiving NCG and Arg. Compared with the IUGR group, the IUGR groups receiving NCG and Arg had 13.2%–62.6% greater (P < 0.05) serum concentrations of arginine, cysteine, isoleucine, and proline. Dietary NCG or Arg to IUGR lambs resulted in greater protein abundance (P < 0.05) of peptide transporter 1 (41.9% or 38.2%) in the ileum compared with the unsupplemented IUGR lambs, respectively. Furthermore, dietary NCG or Arg treatment normalized the IUGR-induced variation (P < 0.05) in the ileal ratio of phosphorylated mTOR to total mTOR protein. Conclusion Both NCG and Arg can help mitigate the negative effect of IUGR on nutrient absorption in neonatal lambs.

Placental mTOR links maternal nutrient availability to fetal growth

2009 ◽  
Vol 37 (1) ◽  
pp. 295-298 ◽  
Author(s):  
Sara Roos ◽  
Theresa L. Powell ◽  
Thomas Jansson
Keyword(s):  
Amino Acid ◽  
Fetal Growth ◽  
Intrauterine Growth Restriction ◽  
Fat Body ◽  
Mammalian Target Of Rapamycin ◽  
Amino Acid Transporters ◽  
Acid Transport ◽  
Intrauterine Growth ◽  
Mtor Activity ◽  
Mtor Signalling

The mTOR (mammalian target of rapamycin) signalling pathway functions as a nutrient sensor, both in individual cells and, more globally, in organs such as the fat body in Drosophila and the hypothalamus in the rat. The activity of placental amino acid transporters is decreased in IUGR (intrauterine growth restriction), and recent experimental evidence suggests that these changes contribute directly to the restricted fetal growth. We have shown that mTOR regulates the activity of the placental L-type amino acid transporter system and that placental mTOR activity is decreased in IUGR. The present review summarizes the emerging evidence implicating placental mTOR signalling as a key mechanism linking maternal nutrient and growth factor concentrations to amino acid transport in the human placenta. Since fetal growth is critically dependent on placental nutrient transport, placental mTOR signalling plays an important role in the regulation of fetal growth.

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