Smoking and preterm labor: effect of a cigarette smoke extract on the secretion of platelet-activating factor-acetylhydrolase by human decidual macrophages.

OBJECTIVE

Maternal smoking in pregnancy is associated with a significant increase in the incidence of preterm labor, premature rupture of membranes, and premature delivery. Our aim was to clarify the cause underlying this association.

STUDY DESIGN

The effect of cigarette smoke extract on the secretion of platelet-activating factor-acetylhydrolase by both decidual macrophages and peripheral blood monocytes and macrophages was investigated.

RESULTS

The cigarette smoke extract inhibited the platelet-activating factor-acetylhydrolase secretion by these cells. The inhibitory effect of cigarette smoke extract on the secretion was a hundred times more potent compared with its direct effect on the plasma enzyme. Glutathione and dithiothreitol blocked the inhibition, whereas catalase or superoxide dismutase did not. Nicotine and cotinine have no effect on the secretion.

CONCLUSION

The presence in cigarette smoke extract of a potent inhibitor(s) of platelet-activating factor-acetylhydrolase secretion by decidual macrophages may provide an insight into the pathogenesis of preterm labor, premature rupture of membranes, and premature delivery in women who smoke during pregnancy.