Inflammatory Cytokine and Thrombin Regulation of Interleukin-8 and Intercellular Adhesion Molecule-1 Expression in First Trimester Human Decidua

Abstract

Decidual neutrophil infiltration complicates spontaneous abortions associated with inflammation and hemorrhage. Transendothelial neutrophil migration into inflamed tissues involves IL-8-mediated chemoattraction, then neutrophil attachment to endothelial cell-expressed intercellular adhesion molecule-1 (ICAM-1). The aim of this study was to assess IL-8 and ICAM-1 regulation in decidual inflammation and hemorrhage; the effects of the proinflammatory cytokines, TNFalpha, IL-1beta and the hemostatic, proinflammatory cytokine thrombin were measured on IL-8 expression in first trimester decidual cells (DCs), and ICAM-1 immunostaining was compared in normal, inflamed, and hemorrhagic first trimester decidua. Immunohistochemistry of human decidua and in vitro treatment of human decidual cells were performed. The study was conducted at the Academic Medical Center. . DCs were passaged until they were leukocyte-free (CD45 free by FACS), then were incubated with estradiol or medroxyprogesterone acetate alone or with TNFalpha or IL-1beta or thrombin. Normal, inflamed, and hemorrhagic decidua were immunostained for ICAM-1 and the neutrophil marker CD14. ICAM-1 immunostaining was performed in decidua. IL-8 levels in DC-conditioned media were assessed by ELISA and immunoblotting; IL-8 mRNA levels were measured by quantitative RT-PCR. Endothelial cell ICAM-1 immunostaining was similar in normal and inflamed or hemorrhagic decidua. In cultured DCs, optimal concentrations of IL-1beta, TNFalpha, and thrombin elevated secreted IL-8 levels by 1083 +/- 261-, 370 +/- 77-, and 45 +/- 15-fold, respectively (mean +/- SEM; P < 0.05; n = 8). The effects were dose dependent and were unaffected by medroxyprogesterone acetate. Western blotting confirmed the ELISA results, and corresponding effects on IL-8 mRNA levels were observed. Cytokine/thrombin-enhanced DC IL-8 expression interacts with constitutively expressed ICAM-1 in decidual endothelium to modulate neutrophil trafficking into hemorrhagic and inflamed first trimester decidua.