Masako Araki

Human Villous Macrophage-Conditioned Media Enhance Human Trophoblast Growth and Differentiation In Vitro

Abstract In human chorionic villi, numerous macrophages, so-called Hofbauer cells, are located adjacent to trophoblasts. To determine the role of the macrophages in the proliferation and differentiation of trophoblasts, cytotrophoblast cells were cultured in serum-free culture-conditioned media of villous macrophages (VMCM), peritoneal macrophages (PMCM), and villous fibroblasts (VFCM). In VMCM, proliferation of cytotrophoblast cells was detected at 24 h by immunocytochemistry with Ki-67-antibody. A large number (P < 0.001) of multinucleated syncytia was formed in VMCM. In VMCM, cytotrophoblast cell fusion was completed by 96 h, which coincided with the peak of hCG secretion and initiation of human placental lactogen (hPL) release. Levels of hCG (P < 0.001) and hPL (P < 0.001) secretion from syncytial cells were significantly higher in VMCM than in PMCM or in VFCM. Concentrations of macrophage colony-stimulating factor (M-CSF) and vascular endothelial growth factor (VEGF) analyzed by ELISA were greater in VMCM than in PMCM or in VFCM, whereas monocyte chemoattractant protein-1 (MCP-1) concentration was high in PMCM. The expression patterns of M-CSF, VEGF, and MCP-1 in villous macrophages and peritoneal macrophages by reverse transcriptase-polymerase chain reaction were similar to their secretion patterns. Thus, villous macrophages have a greater ability to stimulate hCG and hPL secretion than do peritoneal macrophages. This study suggests that macrophages within the villous stroma may stimulate the growth and differentiation of trophoblasts through their secreted substances.

Role of macrophages in ovarian follicular development

The effects of macrophages on granulosa cell proliferation were examined using gonadotropin-primed immature female rats and osteopetrotic (op/op) mice, a model defective in monocyte-macrophage lineage cells. Macrophages were found in the follicles at various developmental stages in rats and mice. The labeling index with [3H]thymidine of cultured rat granulosa cells was maximal when they were cultured with peritoneal macrophages at a macrophages:granulosa cell ratio of 0.01. This ratio was similar to those in rat preantral and antral follicles in vivo. In op/op mice, the number of developing follicles was markedly reduced, but increased after daily macrophage-colony-stimulating factor (M-CSF) administration. In the antral follicles of op/op mice, both granulosa cells and macrophages were significantly decreased in number but were increased after M-CSF treatment. Double immunohistochemical staining revealed that epidermal growth factor (EGF)-positive cells were macrophages in the developing rat follicles. These findings suggest that macrophages are located in the developing follicles and participate in promoting granulosa cell growth through a paracrine mechanism by secreting EGF and other cytokines.

Expression of monocyte chemoattractant protein-1 in peritoneal endometriotic cells

Abstract. It is well known that the number of peritoneal macrophages is increased in patients with pelvic endometriosis. We measured the concentration of monocyte chemoattractant protein-1 (MCP-1) using an enzyme-linked immunosorbent assay (ELISA) in the peritoneal fluid of women with and without endometriosis. The expression of MCP-1 in pelvic endometriotic lesions obtained from the peritoneum was also examined using immunohistochemistry and nonradioactive in situ hybridization. The mean concentration of MCP-1 in the peritoneal fluid was significantly higher in the patients with endometriosis (P<0.05). The most significant elevation, compared with non-endometriosis patients, was found in stage I of the disease (P<0.05). However, no statistically significant difference was found among endometriosis stages I, II, III, and IV. Immunohistochemical staining revealed that MCP-1-positive cells were localized in the glandular epithelium of the endometriotic lesions and in the stromal macrophages distributed in those lesions, but normal peritoneal cells were negative. The in situ hybridization method demonstrated expression of MCP-1 mRNA on the endometriotic glandular epithelium and stromal macrophages. These findings suggest that MCP-1 may be involved in the histogenesis and early development of peritoneal endometriosis.

Development and Distribution of T Cell-Associated Dendritic Cells in Organs and Tissues of Mice Depleted of Blood Monocytes by Administration of Strontium-89

In the development and differentiation of T cell-associated dendritic cells (epidermal Langerhans cells, interdigitating cells in the paracortex of lymph node, and veiled cells in the dermis and within the afferent lymphatics), the importance of granulocyte-macrophage colony-stimulating factor (GM-CSF) has been pointed out. This fact was based on the results of previous studies of in vitro response of dendritic cells to GM-CSF1 and studies on osteopterosis (op) mice lacking functionally active macrophage colony-stimulating factor (M-CSF).2 Recently, a few groups of investigators have succeeded in generating dendritic cells in cultures of bone marrow cells with GM-CSF in mice3 and humans.4 However, the relationship between dendritic cells and blood monocytes still remains unclear. To elucidate it, it is necessary to investigate the behavior of the dendritic cells in a condition extremely depleted of blood monocyte.