title: Colocalisation of vascular endothelial growth factor and its Flt-1 receptor in human placenta.
abstract: Vascular endothelial growth factor (VEGF) is an angiogenic protein which acts on both endothelial and trophoblast cells. In first trimester placenta, VEGF immunoreactive protein was detected in cytotrophoblast shell suggesting a role in the regulation of cytotrophoblast growth and differentiation as they also expressed VEGF receptor (flt-1) protein. VEGF and flt-1 immunoreactive proteins were expressed in Hofbauer cells within the villous mesenchyme, macrophages and in maternal decidual cells while weak VEGF immunoreactive protein was seen in syncytiotrophoblast surrounding the placental villi in first and second trimester placentae. At term, there was relatively weak VEGF and flt-1 immunostaining in the syncytiotrophoblast while intense VEGF immunostaining was seen in the Hofbauer and maternal decidual cells. Extravillous trophoblast showed immunostaining for flt-1 but no staining for VEGF. Both amnion and chorion expressed strong VEGF immunoreactivity throughout gestation. Smooth muscle cells surrounding the vein and arteries of the umbilical cord showed weak VEGF immunoreactivity while no immunoreactivity was localised in endothelial cells. VEGF stimulated parathyroid hormone-related protein (PTHrP) release (mean (+/- SD): basal, 0.96 +/- 0.03; 10 ng/ml VEGF165, 2.07 +/- 0.18 and 20 ng/ml VEGF165, 2.43 +/- 0.18 pmol/l/well of PTHrP1-86) in condition medium from immortalised first trimester trophoblast cell line. These results suggest that VEGF in addition to acting as an autocrine mitogen for trophoblast proliferation may also function as a paracrine mediator of vascular tone by releasing vasorelaxants from trophoblasts.
authors.affiliation: Centre for Clinical Research in Immunology and Signalling, Medical School, University of Birmingham, Edgbaston, UK.
authors.forename: A
authors.initials: A
authors.lastname: Ahmed
authors.forename: X F
authors.initials: XF
authors.lastname: Li
authors.forename: C
authors.initials: C
authors.lastname: Dunk
authors.forename: M J
authors.initials: MJ
authors.lastname: Whittle
authors.forename: D I
authors.initials: DI
authors.lastname: Rushton
authors.forename: T
authors.initials: T
authors.lastname: Rollason
mesh_terms: D002454:Cell Differentiation; D002455:Cell Division; D002478:Cells, Cultured; D003656:Decidua / Q000166:cytology / Q000378:metabolism; D016228:Endothelial Growth Factors / Q000032:analysis / Q000378:metabolism*; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D015592:Immunoradiometric Assay; D008222:Lymphokines / Q000032:analysis / Q000378:metabolism*; D044162:Parathyroid Hormone-Related Protein; D010920:Placenta / Q000166:cytology / Q000378:metabolism*; D011247:Pregnancy; D011261:Pregnancy Trimester, First; D011506:Proteins / Q000032:analysis; D011518:Proto-Oncogene Proteins / Q000032:analysis / Q000378:metabolism*; D020794:Receptor Protein-Tyrosine Kinases / Q000032:analysis / Q000378:metabolism*; D014327:Trophoblasts / Q000166:cytology / Q000378:metabolism; D042461:Vascular Endothelial Growth Factor A; D040281:Vascular Endothelial Growth Factor Receptor-1; D042442:Vascular Endothelial Growth Factors
chemical_list: D016228:Endothelial Growth Factors; D008222:Lymphokines; C470121:PTHLH protein, human; D044162:Parathyroid Hormone-Related Protein; D011506:Proteins; D011518:Proto-Oncogene Proteins; C467484:VEGFA protein, human; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; D020794:Receptor Protein-Tyrosine Kinases; D040281:Vascular Endothelial Growth Factor Receptor-1