Decidual histamine release and amplification of prostaglandin F2 alpha production by histamine in interleukin-1 beta-primed decidual cells: potential interactive role for inflammatory mediators in uterine function at term.

Inflammatory cytokines such as interleukin-1 (IL-1) have been implicated as paracrine mediators of decidual prostaglandin (PG) production during preterm labor. The aim of the present in vitro study was to investigate a similar potential role for the inflammatory autacoid histamine. Histamine action on human primary decidual cell cultures was monitored by measuring both PGF2 alpha production and PG precursor release. Histamine release from decidual cell suspensions was measured in response to a variety of putative mast cell secretagogues. Histamine stimulated a dose-dependent increase in PGF2 alpha production and [14C]arachidonate release from prelabeled decidual cells, with ED50 values around 1 and 2 mumol/L, respectively. Pretreatment of cells with IL-1 beta enhanced maximal PGF2 alpha production in response to histamine by approximately 4-fold. Mepyramine, an H1 receptor antagonist, completely blocked this PGF2 alpha response. The mean histamine content of unpurified decidual cells was approximately 81 pmol/10(6) cells. Upon challenge with antihuman immunoglobulin E, these cells exhibited a dose-dependent release of histamine. Basal release from decidual cell suspensions and release in response to antiimmunoglobulin E (1:400) or A23187 (1 mumol/L) were 7.6 +/- 2.7%, 25.5 +/- 0.9%, and 63.5 +/- 5.6% of the total histamine content, respectively. No significant changes in histamine secretion were seen in response to compound 48/80, substance-P, phorbol ester, or bacterial endotoxin. These in vitro findings support a potential role for histamine as a local regulator of phospholipase-A2 and PGF2 alpha production in human term decidua. The interaction of this autacoid with other inflammatory mediators, such as IL-1, could play a role in the control of PG production during preterm labor.