The production of prostanoids and the identification of macrophages in human decidua vera tissue.

In decidual tissues of first trimester therapeutic abortions we have identified a large macrophage population that is stained by a specific antibody (Ki-M8). Also, we evaluated the capacity of decidual cells, obtained before and after labor, to synthesize prostanoids from radiolabeled arachidonic acid. Decidua collected after vaginal delivery produced significantly more prostaglandin (PG) F2 alpha, PGE2 and thromboxane (TX) B2 (7.4 +/- 1.3, 7.2 +/- 1.3, 11.7 +/- 1.1 pmol/mg protein/4 h, mean +/- SD, respectively) than did tissues from women who had caesarean sections (3.3 +/- 0.8, 1.4 +/- 0.5, 6.3 +/- 1.8 pmol/mg protein/4 h, respectively). Moreover, PGF2 alpha and PGE2 were rapidly converted to their 13,14-dihydro-15-keto-metabolites particularly in tissues obtained after vaginal delivery. All this lends further support to the proposition that decidual activation may be important in the onset of labor.