Inhibitory effect of interleukin-8 on the secretion of platelet-activatingfactor acetylhydrolase by human decidual macrophages

OBJECTIVE: To determine whether interleukin-8 (IL-8) regulates platelet-act ivating factor acetylhydrolase (PAF-AH) secretion by decidual cells in vitr o. METHODS: Decidual macrophages were obtained from human term dicidual tissue by enzymic digestion and Ficoll-Paque centrifugation. The effect of IL-8 a nd phorbol esters on the secretion of PAF-acetylhydrolase by these cells wa s examined. RESULTS: IL-8 inhibited PAF-AH secretion by decidual macrophages in a dose- dependent manner. The inhibition was reversed partially by antibodies again st tumor necrosis factor-alpha and IL-1 beta. IL-8-induced inhibition was b locked partially by the protein kinase C (PKC) inhibitors, sphingosine, and H-7 1-(5-isoquinoline sulfonyl)-2-methylpiperazine. A PKC activator, 12-O- tetradecanoyl phorbol 13-acetate, decreased PAF-AH secretion. CONCLUSION: IL-8 may increase the PAF concentration in the decidua via its inhibitory effect on PAF-AH secretion by decidual macrophages. IL-8-induced inhibition of enzyme secretion may have been mediated in part by PKC-depen dent signal transduction. (J Soc Gynecol Investig 1999;6:328-32) Copyright (C) 1999 by the Society for Gynecologic Investigation.