Isolation of macrophages (Hofbauer cells) from human term placenta and their prostaglandin E-2 and thromboxane production

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% O-2 or 5% O-2, fresh medium was applied and PGE(2) and thromboxane (TXA(2)) production analysed by enzyme immunoassay at 4, 8, and 24 h, PGE(2) and TXA(2) were both produced by placental macrophages with PGE(2) synthesis being predominant, Concentrations of both could be stimulated by lipopolysaccharide with maximum effect after 24 h. Culture in low oxygen caused decreased PGE(2) concentrations, whereas TXA(2) 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.