Defecation in utero: A physiologic fetal function

Objective: The aim is to clarify the role of platelet-activating factor and colony-stimulating factors in term and preterm parturition. Study Design: Decidual macrophage populations were obtained by an enzymic digestion, Ficoll-Paque centrifugation, or flow cytometric sorting. The effects of colony-stimulating factors on the platelet-activating factor acetylhydrolase secretion by these cells were examined. Results: Granulocyte-macrophage colony-stimulating factor inhibited the platelet-activating factor acetylhydrolase secretion by decidual macrophages. Granulocyte colony-stimulating factor also decreased the enzyme secretion but at higher concentrations than those required for granulocyte colony-stimulating factor. In contrast, macrophage colony-stimulating factor increased the enzyme secretion. These colony-stimulating factor-induced effects were specifically neutralized by the corresponding antibodies. Conclusion: Colony-stimulating factors may modulate the local concentration of platelet-activating factor in the decidua via their inhibitory or stimulatory effect on the secretion of platelet-activating factor acetylhydrolase, contributing to the regulation of term and preterm parturition at the maternal-fetal interface. (Am J Obstet Gynecol 2003;188:157-61.)