Comparison of expression patterns for placenta growth factor, vascular endothelial growth factor (VEGF), VEGF-B and VEGF-C in the human placenta throughout gestation

Angiogenesis and vascular transformation are important processes in the nor mal development of the placenta. Vascular endothelial growth factor (VEGF) is a potent angiogenic growth factor and is thought to be important for pla cental development. Recently several new members of this family have been d escribed. In this study we used in situ hybridisation to localise which cel ls in the placenta expressed mRNA for VEGF, placenta growth factor (PlGF), VEGF-B and VEGF-C. We were unable to find any message for either VEGF-B or VEGF-C in the placenta, suggesting that only low levels are produced which this method was unable to detect. The mRNA encoding VEGF was found to be pr oduced by cells within the villous mesenchyme, decidual macrophages and dec idual glands but, in contrast to our previous findings, not by trophoblast. The mRNA encoding PlGF was produced in large amounts by villous cytotropho blast, syncytiotrophoblast and extravillous trophoblast. The mRNAs encoding VEGF and PlGF were thus not co-localised and it appears that there is unli kely to be any significant production of VEGF/PlGF heterodimer in the place nta.