Isolation of macrophages (Hofbauer cells) from human term placenta and their prostaglandin E2 and thromboxane production

Abstract

Placental macrophages (Hofbauer cells) are located close to trophoblast cells and fetal capillaries, which makes them ideal candidates for involvement in regulatory processes within the villous core. Their production of various cytokines and prostaglandin (PG) synthesizing enzymes has previously been shown immunohistochemically. Hofbauer cells were isolated from human placenta after term deliveries by Ficoll and Percoll gradient centrifugation. Remaining trophoblast cells were removed with anti-epidermal growth factor (EGF)-receptor-coated Dynabeads followed by differential adherence. The identity of isolated cells was investigated by immunohistochemistry with anti-CD68, which showed that >90% cells were positive. After a 36 h recovery period in either 20% O2 or 5% O2, fresh medium was applied and PGE2 and thromboxane (TXA2) production analysed by enzyme immunoassay at 4, 8, and 24 h. PGE2 and TXA2 were both produced by placental macrophages with PGE2 synthesis being predominant. Concentrations of both could be stimulated by lipopolysaccharide with maximum effect after 24 h. Culture in low oxygen caused decreased PGE2 concentrations, whereas TXA2 production remained unchanged. In conclusion, the presented isolation protocol allows further study of Hofbauer cell function. This study also presents novel findings regarding the prostaglandin production of term Hofbauer cells under normal and hypoxic conditions.

Expression of VEGF and CD68 in the Placenta of Gestational Diabetic Mothers (Immunohistochemistry and Ultrastructural Study)

“…MHC class I-II antigens and various interleukins are produced in Hofbauer cells, and these may play a role in immunological reactions within the placental villi. These cells may participate in placental inflammation or fetal immunological mechanisms, such as tolerance and fetal protection (Wetzka et al, 1997). In this study, we noted a decrease in the number of vascular endothelial cells and cell hyperplasia.…”

Obesity in Pregnancy Stimulates Macrophage Accumulation and Inflammation in the Placenta

“…Resident macrophages which initially colonize the placental villi differentiate from primitive fetal macrophages without passing through the monocyte lineage [14,34]. They represent the primitive macrophages known as Hofbauer cells which can be identified by CD68 staining [35]. Their high intrinsic proliferative and mitogenic capacities suggest that in situ mitogenesis may contribute to the enrichment we observed in the present study [36,37].…”

Ontogenesis of Villi and Fetal Vessels in the Human Placenta

“…At term, they are observed in all parts of the stroma but are concentrated in the subtrophoblastic area and in the border of the vascular media. Their vasomotor role is attributed to their production of the E 2 prostaglandins and thromboxane [72]. They could also participate both in angiogenesis [2], as they contain FGF, and in the inflammatory reaction caused by placentation, as they release TNF [64].…”