Reproduction Abstracts

Introduction: Decidual macrophages constitute the second largest leukocyte cell type in the decidua during early pregnancy, and have been implicated in the regulation of extravillous trophoblast (EVT) invasion. Macrophage cells in the decidua are thought to have an anti-inflammatory M2 phenotype and the presence of macrophages with a more pro-inflammatory M1 phenotype has been associated with preeclampsia. The aim of this study was to determine whether decidual macrophage polarisation state has an impact upon EVT behaviour.

Materials and methods: The human acute monocytic leukemia cell line (THP-1) was differentiated with phorbol 12-myristate 13-acetate (PMA) into macrophages. Once differentiated, the cells were polarised using LPS and IFN-γ to generate M1 macrophages, or IL4 and IL13 to generate M2 macrophages. Culture supernatant from the polarised cells was used to treat SGHPL-4 cells, a cell line derived from first-trimester EVT, and SGHPL-4 cell death, proliferation, motility and invasion were analysed.

Results and discussion: Culture supernatant from the M1 macrophages was found to significantly reduce SGHPL-4 motility when compared with the M2 macrophages and the media control.The culture supernatant from both M1 and M2 macrophages was found to inhibit SGHPL-4 proliferation but increase SGHPL-4 invasion, when compared with the media control. No effect upon SGHPL-4 cell death was observed with any of the treatments. Thus, the polarisation state of macrophage-like THP-1 cells impacts upon their ability to regulate extravillous trophoblast motility in-vitro indicating that decidual macrophage polarisation state may have an important role in the regulation of placental development.