To study vascular endothelial growth factor (VEGF) and placenta growth factor (PlGF) concentrations and their possible binders, serum from 22 non-pregnant and 55 pregnant women (15 at weeks 10–13; 40 at term), umbilical vein (n = 24) and artery (n = 13) and amniotic fluid (a pool of 50 at weeks 15–17; 11 at term) were assessed for VEGF and PlGF by an enzyme-linked immunosorbent assay. In amniotic fluid and maternal serum VEGF concentrations were <16 ng/ml and added VEGF was not recovered. VEGF was detected in serum from mothers post-partum (137 ± 142 ng/l, mean ± SD), umbilical artery (421 ± 288 ng/l) and vein (502 ± 339 ng/l) and non-pregnant controls (182 ± 147 ng/l), and added VEGF was fully recovered. PlGF was detected in pregnancy serum (52 ± 23 ng/l early pregnancy; 439 ± 217 ng/l term pregnancy) and in amniotic fluid (early pregnancy 56 ng/l; term pregnancy 30 ± 18 ng/l). PlGF was fully recovered in all samples. Gel filtration and isoelectric focusing revealed that in maternal serum and amniotic fluid [125I]VEGF was bound to a protein with an Mr of 400–700 kDa and an isoelectric point of approximately 8. This protein was not identical with alpha-2-macroglobulin (by an immunofluorometric assay), pregnancy zone protein or pregnancy associated plasma protein-A (by immunodiffusion). In conclusion, VEGF-binding activity is present in amniotic fluid and maternal blood. It disappears after delivery and is not detectable in fetal or non-pregnant serum.
Keywords: amniotic fluid; PlGF; pregnancy-associated binding; VEGF
Journal Article. 4388 words. Illustrated.
Subjects: Reproductive Medicine
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