Preeclampsia Is Associated with Decreased Placental Interleukin-6 Production

Abstract

Objective: The etiology of preeclampsia is poorly understood, but may involve abnormal fetal-matrnal immunologic interactions. Interleukin-6 (IL-6) is a multifunctional immunologic cytokine that is normally produced by the placenta during pregnancy. Recent studies have shown that amniotic fluid IL-6 is decreased in pregnancies complicated by preeclampsia. Consequently, this study was designed to test the hypothesis that placental IL-6 production is decreaseed in preeclampsia.

Methods: Placental explants from normal (N = 6) and preeclamptic (N = 6) pregnancies were cultured in vitro, and the media were sampled at 0, 2, 6, 16, 28, and 48 hours. Production rates of IL-6 were measured by enzyme-linked immunosorbent assay, and relative IL-6 mRNA expression was measured by Northern and dot blot analyses.

Results: Production rates of IL-6 were 2.3-fold lower in preeclamptic placentas than in normal placentas, at 146 pg/μg/hour versus 341 pg/μg/hour (P < .05). However, relative steady-state IL-6 mRNA expression was identical in preeclamptic and normal placentas.

Conclusions: Placental IL-6 production is decreased in preeclampsia. The decrease in placental IL-6 production and secretion in preeclampsia is regulated by a post-transcriptional mechanism.

Keywords

Preeclampsia placenta interleukin-6

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