title: Glucose uptake in the placenta, fetal brain, heart and liver related to blood flow redistribution during acute hypoxia.
abstract: OBJECTIVE
  We used positron emission tomography (PET) with radioactive glucose (F-18-Fluor-Deoxglucose [FDG]) to investigate whether acute maternal hypoxemia causes alterations of glucose uptake of fetal organs and the placenta.
  
  
  METHODS
  Investigation was performed under normal conditions and acute hypoxemia in 16 fetal sheep between 108 and 130 days of gestation. Maternal sheep were ventilated with 1.0-1.5% isoflurane/O(2) /N(2) O during whole scanning procedure. Acute hypoxia was induced by reducing O(2) in a ventilated gas mixture to achieve maternal arterial O(2) saturation at a constant level of about 75% baseline. Doppler ultrasound blood flow measurements were performed in the ductus venosus (DV), umbilical artery (UA) and vein (UV). Fetal blood samples were taken by cordocentesis of UV. Dynamic positron emission tomography combined with computed tomography (PET-CT) scans of fetuses were acquired over 60 min after intravenous injection of 300 MBq FDG in the mother. Relative FDG uptake in the fetal brain, heart, and liver was determined on summed images from 40-60 min using manually defined volumes of interest (VOI) normalized to mean FDG uptake in placentomes.
  
  
  RESULTS
  Placental blood perfusion reduced significantly from 416.5 ± 116.4 mL/min to 253.5 ± 170.5 mL/min (mean ± SD) during hypoxia. Placental blood supply to the liver decreased from 79.5 ± 14% to 41.1% (P = 0.0001), while DV/UV ratio increased. FDG uptake of the placenta was not changed during hypoxia. Relative FDG uptake in the fetal heart was strongly increased under hypoxia (P = 0.019), whereas it did not differ in the fetal brain and liver.
  
  
  CONCLUSIONS
  Fetal hypoxia is associated with decreased placental perfusion and liver blood supply. However, glucose uptake was not significantly decreased in the placenta and liver.
authors.affiliation: Department of Obstetrics and Prenatal Medicine, University Medical Center Mainz, Mainz, Germany. tchirikov@uni-mainz.de
authors.forename: Michael
authors.initials: M
authors.lastname: Tchirikov
authors.forename: Miriam
authors.initials: M
authors.lastname: Tchirikov
authors.forename: Ralph
authors.initials: R
authors.lastname: Buchert
authors.forename: Florian
authors.initials: F
authors.lastname: Wilke
authors.forename: Winfried
authors.initials: W
authors.lastname: Brenner
mesh_terms: D000818:Animals; D001692:Biological Transport; D001921:Brain / Q000098:blood supply / Q000196:embryology / Q000378:metabolism; D003331:Coronary Vessels / Q000196:embryology / Q000503:physiopathology; D005260:Female; D005311:Fetal Hypoxia / Q000378:metabolism / Q000503:physiopathology; D005333:Fetus / Q000098:blood supply* / Q000378:metabolism*; D005947:Glucose / Q000378:metabolism*; D000860:Hypoxia / Q000378:metabolism* / Q000503:physiopathology; D008099:Liver / Q000098:blood supply / Q000196:embryology / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D010920:Placenta / Q000098:blood supply / Q000378:metabolism*; D021041:Placental Circulation; D011247:Pregnancy; D012039:Regional Blood Flow; D034561:Sheep, Domestic
chemical_list: D005947:Glucose