Context: 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).
Objective: 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.
Design: Immunohistochemistry of human decidua and in vitro treatment of human decidual cells were performed.
Setting: The study was conducted at the Academic Medical Center.
Intervention: . 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.
Main outcome measure: 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.
Results: 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.
Conclusions: 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.