title: Increased glucose and placental GLUT-1 in large infants of obese nondiabetic mothers.
abstract: OBJECTIVE
  Obese women are at increased risk to deliver a large infant, however, the underlying mechanisms are poorly understood. Fetal glucose availability is critically dependent on placental transfer and is linked to fetal growth by regulating the release of fetal growth hormones such as insulin. We hypothesized that (1) umbilical vein glucose and insulin levels and (2) placental glucose transporter (GLUT) expression and activity are positively correlated with early pregnancy maternal body mass index and infant birthweight.
  
  
  METHODS
  Subjects in this prospective observational cohort study were nondiabetic predominantly Hispanic women delivered at term. Fasting maternal and umbilical vein glucose and insulin concentrations were determined in 29 women with varying early pregnancy body mass index (range, 18.0-54.3) who delivered infants with birthweights ranging from 2800-4402 g. We isolated syncytiotrophoblast microvillous and basal plasma membranes from 33 placentas and determined the expression of GLUT-1 and -9 (Western blot) and glucose uptake (radiolabeled glucose).
  
  
  RESULTS
  Birthweight was positively correlated with umbilical vein glucose and insulin and maternal body mass index. Umbilical vein glucose levels were positively correlated with placental weight and maternal body mass index, but not with maternal fasting glucose. Basal plasma membranes GLUT-1 expression was positively correlated with birthweight. In contrast, syncytiotrophoblast microvillous GLUT-1 and -9, basal plasma membranes GLUT-9 expression and syncytiotrophoblast microvillous and basal plasma membranes glucose transport activity were not correlated with birthweight.
  
  
  CONCLUSIONS
  Because maternal fasting glucose levels and placental glucose transport capacity were not increased in obese women delivering larger infants, we speculate that increased placental size promotes glucose delivery to these fetuses.
authors.affiliation: Department of Obstetrics and Gynecology, Center for Pregnancy and Newborn Research, University of Texas Health Science Center at San Antonio, San Antonio, TX. Electronic address: acostao@uthscsa.edu.
authors.forename: Ometeotl
authors.initials: O
authors.lastname: Acosta
authors.affiliation: Department of Obstetrics and Gynecology, Center for Pregnancy and Newborn Research, University of Texas Health Science Center at San Antonio, San Antonio, TX.
authors.forename: Vanessa I
authors.initials: VI
authors.lastname: Ramirez
authors.affiliation: Department of Obstetrics and Gynecology, Center for Pregnancy and Newborn Research, University of Texas Health Science Center at San Antonio, San Antonio, TX.
authors.forename: Susanne
authors.initials: S
authors.lastname: Lager
authors.affiliation: Department of Obstetrics and Gynecology, Center for Pregnancy and Newborn Research, University of Texas Health Science Center at San Antonio, San Antonio, TX.
authors.forename: Francesca
authors.initials: F
authors.lastname: Gaccioli
authors.affiliation: Department of Obstetrics and Gynecology, Center for Pregnancy and Newborn Research, University of Texas Health Science Center at San Antonio, San Antonio, TX.
authors.forename: Donald J
authors.initials: DJ
authors.lastname: Dudley
authors.affiliation: Department of Obstetrics and Gynecology, Center for Pregnancy and Newborn Research, University of Texas Health Science Center at San Antonio, San Antonio, TX.
authors.forename: Theresa L
authors.initials: TL
authors.lastname: Powell
authors.affiliation: Department of Obstetrics and Gynecology, Center for Pregnancy and Newborn Research, University of Texas Health Science Center at San Antonio, San Antonio, TX.
authors.forename: Thomas
authors.initials: T
authors.lastname: Jansson
mesh_terms: D000328:Adult; D001724:Birth Weight / Q000502:physiology*; D001786:Blood Glucose / Q000378:metabolism*; D015992:Body Mass Index; D016022:Case-Control Studies; D015331:Cohort Studies; D005260:Female; D005320:Fetal Macrosomia / Q000097:blood / Q000378:metabolism; D051246:Glucose Transport Proteins, Facilitative / Q000378:metabolism*; D051272:Glucose Transporter Type 1 / Q000378:metabolism*; D006801:Humans; D007231:Infant, Newborn; D007328:Insulin / Q000097:blood*; D008297:Male; D008431:Maternal-Fetal Exchange / Q000502:physiology; D009765:Obesity / Q000097:blood* / Q000378:metabolism; D009929:Organ Size; D010920:Placenta / Q000378:metabolism*; D010929:Placentation; D011247:Pregnancy; D011248:Pregnancy Complications / Q000097:blood* / Q000378:metabolism; D011446:Prospective Studies; D014327:Trophoblasts / Q000378:metabolism; D014471:Umbilical Veins
chemical_list: D001786:Blood Glucose; D051246:Glucose Transport Proteins, Facilitative; D051272:Glucose Transporter Type 1; D007328:Insulin; C495677:SLC2A1 protein, human; C411811:SLC2A9 protein, human
keywords: fetal growth; maternal obesity; maternal-fetal exchange; trophoblast