The vitamin E-binding protein afamin increases in maternal serum during pregnancy.
BACKGROUND
Afamin is a liver-derived plasma glycoprotein with vitamin E-binding properties and a putative function in fertility. This study evaluated serum afamin concentrations during and postpartum to uncomplicated pregnancies and investigated a potential association between afamin concentrations and pregnancy outcome.


METHODS
Afamin serum concentrations were measured in women with uncomplicated pregnancies in a retrospective cohort (n=466) at different gestational ages and a prospective observational study (n=76) in the first, second and third trimester. Furthermore, afamin was determined in the first trimester in a cross-sectional pilot study including women with preeclampsia (PE), pregnancy-induced hypertension (PIH) and women without pregnancy complications (n=13 each). Finally, expression of afamin was investigated in human placental tissue by RT-PCR and immunohistochemistry.


RESULTS
Afamin concentrations increased linearly almost two-fold during pregnancy in both retrospective and prospective studies in women without pregnancy complications with median afamin serum concentrations of 61.9 mg/l, 79.6 mg/l, and 98.6 mg/l in the first, second, and third trimester, respectively. After delivery, median afamin concentrations decreased to baseline values of 54.6 mg/l. In the pilot study with pregnancy complications, women with PE displayed significantly higher median afamin concentrations than did women with uncomplicated pregnancy (70.0 mg/l vs. 55.4 mg/l, P=0.007). Expression analyses revealed no placental afamin expression at either mRNA or protein level in uncomplicated pregnancy.


CONCLUSIONS
A linear increase in the maternally expressed glycoprotein afamin during pregnancy may serve as basic reference for subsequent investigations of afamin in pregnancy-related disorders.
Department of Gynecology and Obstetrics, Innsbruck Medical University, Innsbruck, Austria.
Michael
M
Hubalek
Institute of Medical Informatics, Biometry and Epidemiology, Medical School, Ludwig Maximilian University of Munich, Germany.
Hannes
H
Buchner
Department of Gynecology and Obstetrics, Medical University of Graz, Austria.
Manfred G
MG
Mörtl
Department of Gynecology and Obstetrics, Medical University of Graz, Austria; Department of Gynecology and Obstetrics, Jena University, Jena, Germany.
Dietmar
D
Schlembach
Institute of Cell Biology, Histology and Embryology, Medical University of Graz, Austria.
Berthold
B
Huppertz
Department of Gynecology and Obstetrics, Innsbruck Medical University, Innsbruck, Austria.
Branka
B
Firulovic
Department of Laboratory Medicine, Konventhospital Barmherzige Brüder, Linz, Austria.
Wolfgang
W
Köhler
Department of Obstetrics and Gynecology, Danube Hospital/SMZ-Ost, Vienna, Austria.
Erich
E
Hafner
Department of Laboratory Medicine, Konventhospital Barmherzige Brüder, Linz, Austria.
Benjamin
B
Dieplinger
Department of Gynecological Endocrinology and Reproductive Medicine, Innsbruck Medical University, Innsbruck, Austria.
Ludwig
L
Wildt
Division of Genetic Epidemiology, Department of Medical Genetics, Clinical and Molecular Pharmacology, Innsbruck Medical University, Innsbruck, Austria; Vitateq Biotechnology GmbH, Innsbruck, Austria. Electronic address: hans.dieplinger@i-med.ac.at.
Hans
H
Dieplinger
D000328:Adult; D002352:Carrier Proteins / Q000097:blood*; D003430:Cross-Sectional Studies; D005260:Female; D005786:Gene Expression Regulation / Q000502:physiology*; D006023:Glycoproteins / Q000097:blood*; D006801:Humans; D010865:Pilot Projects; D011225:Pre-Eclampsia / Q000097:blood / Q000378:metabolism*; D011247:Pregnancy; D011264:Pregnancy Trimesters; D012189:Retrospective Studies; D012709:Serum Albumin; D000075462:Serum Albumin, Human; D014810:Vitamin E / Q000378:metabolism*; D055815:Young Adult
C088246:AFM protein, human; D002352:Carrier Proteins; D006023:Glycoproteins; D012709:Serum Albumin; D014810:Vitamin E; D000075462:Serum Albumin, Human
Afamin in pregnancy; maternal expression; preeclampsia; pregnancy complications