title: Total bile acids in the maternal and fetal compartment in relation to placental ABCG2 expression in preeclamptic pregnancies complicated by HELLP syndrome.
abstract: OBJECTIVE
  To investigate total bile acid (TBA) levels in maternal (MB) and umbilical cord blood (UCB) in normotensive, preeclamptic (PE), and PE pregnancies complicated by hemolysis elevated liver enzymes and low platelets (HELLP) syndrome in the context of ABCG2 placental gene expression levels, a recently reported placental bile acid transporter.
  
  
  METHODS
  TBA levels were determined in 83 paired MB and UCB samples of normotensive, PE and PE/HELLP pregnancies and in 22 paired arterial and venous UCB samples from uncomplicated term pregnancies. ABCG2 gene expression was measured in 104 human placentas by reverse transcriptase quantitative polymerase chain reaction.
  
  
  RESULTS
  Overall, TBA levels in MB are higher compared to levels in UCB (p<0.0001), but this comparison looses statistical significance for the 11 PE/HELLP cases. TBA levels in maternal blood are increased in PE/HELLP compared to PE pregnancies (p=0.016). TBA levels in arterial and venous UCB from 22 normotensive pregnancies are not statistically different. ABCG2 expression is reduced in pregnancies where preeclampsia is further complicated by HELLP syndrome. ABCG2 expression in human placenta is not correlated with TBA levels in either the maternal or fetal compartment.
  
  
  CONCLUSIONS
  Increased maternal TBA levels in PE/HELLP pregnancies indicate a relation between bile acids in the maternal circulation and HELLP syndrome. As overall TBA levels in maternal blood are increased compared to UCB, we conclude that the placenta partly protects the fetus from increased maternal TBA levels. This consistent difference in TBA levels between the maternal and fetal compartment is unrelated to the placental expression of ABCG2.
authors.affiliation: Women's and Children's Clinic, Academic Medical Center, University of Amsterdam, PO Box 22660, Amsterdam 1100 DD, The Netherlands; Department of Obstetrics and Gynaecology, Onze Lieve Vrouwe Gasthuis, PO Box 95500, Amsterdam 1090 HM, The Netherlands. Electronic address: j.m.jebbink@amc.uva.nl.
authors.forename: Jiska
authors.initials: J
authors.lastname: Jebbink
authors.affiliation: Reproductive Biology Laboratory, Academic Medical Center, University of Amsterdam, PO Box 22660, Amsterdam 1100 DD, The Netherlands.
authors.forename: Geertruda
authors.initials: G
authors.lastname: Veenboer
authors.affiliation: Reproductive Biology Laboratory, Academic Medical Center, University of Amsterdam, PO Box 22660, Amsterdam 1100 DD, The Netherlands.
authors.forename: Souad
authors.initials: S
authors.lastname: Boussata
authors.affiliation: Reproductive Biology Laboratory, Academic Medical Center, University of Amsterdam, PO Box 22660, Amsterdam 1100 DD, The Netherlands.
authors.forename: Remco
authors.initials: R
authors.lastname: Keijser
authors.affiliation: Department of Medicine 1, Friedrich-Alexander-University of Erlangen-Nuremberg, Ulmenweg 18, Erlangen 91054, Germany.
authors.forename: Andreas E
authors.initials: AE
authors.lastname: Kremer
authors.affiliation: Tytgat Institute for Liver and Intestinal Research, Department of Gastroenterology and Hepatology, Academic Medical Center, University of Amsterdam, PO Box 22660, Amsterdam 1100 DD, The Netherlands.
authors.forename: Ronald Oude
authors.initials: RO
authors.lastname: Elferink
authors.affiliation: Women's and Children's Clinic, Academic Medical Center, University of Amsterdam, PO Box 22660, Amsterdam 1100 DD, The Netherlands.
authors.forename: Joris
authors.initials: J
authors.lastname: van der Post
authors.affiliation: Reproductive Biology Laboratory, Academic Medical Center, University of Amsterdam, PO Box 22660, Amsterdam 1100 DD, The Netherlands.
authors.forename: Gijs
authors.initials: G
authors.lastname: Afink
authors.affiliation: Women's and Children's Clinic, Academic Medical Center, University of Amsterdam, PO Box 22660, Amsterdam 1100 DD, The Netherlands; Reproductive Biology Laboratory, Academic Medical Center, University of Amsterdam, PO Box 22660, Amsterdam 1100 DD, The Netherlands.
authors.forename: Carrie
authors.initials: C
authors.lastname: Ris-Stalpers
mesh_terms: D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters / Q000235:genetics / Q000378:metabolism*; D000293:Adolescent; D000328:Adult; D001647:Bile Acids and Salts / Q000097:blood / Q000378:metabolism*; D015153:Blotting, Western; D016022:Case-Control Studies; D005260:Female; D005312:Fetal Blood / Q000378:metabolism*; D015870:Gene Expression; D017359:HELLP Syndrome / Q000378:metabolism*; D006801:Humans; D009363:Neoplasm Proteins / Q000235:genetics / Q000378:metabolism*; D010920:Placenta / Q000378:metabolism*; D011225:Pre-Eclampsia / Q000378:metabolism*; D011247:Pregnancy; D055815:Young Adult
chemical_list: C116614:ABCG2 protein, human; D000070997:ATP Binding Cassette Transporter, Subfamily G, Member 2; D018528:ATP-Binding Cassette Transporters; D001647:Bile Acids and Salts; D009363:Neoplasm Proteins
keywords: Bile acids; HELLP; Preeclampsia