In vitro expression of vascular endothelial growth factor and its receptors by placental macrophages

The expression of VEGF and membrane-bound and soluble forms of the VEGF-R1 receptor in cultured placental macrophages (trimesters I and III of pregnancy) was studied by flow cytometry, cytometric bead array, and ELISA. Nearly all population of placental macrophages (98%) was capable of producing VEGF during the early and late gestational periods. However, the expression of cellular VEGF-R1 varied from 3.4 to 92%. VEGF secretion was relatively low in the first and third trimesters (0.5 and 1.1 pg/10(5) cells, respectively). Cultured placental macrophages produced soluble receptor sVEGF-R1 in the first and third trimesters (86.4 and 36.4 pg/10(5) cells, respectively). Stimulation with LPS was followed by a 4-fold increase in sVEGF-R1 secretion. Our results indicate that placental macrophages are involved in the autocrine and paracrine regulation in chorionic villi. The data suggest that these cells have a physiological and pathogenetic role in gestation.