Soluble factors released by placental villous tissue: Interleukin-1 is a potential mediator of endothelial dysfunction

Objective The purpose of this study was to analyze the potential of placental-conditioned medium to activate endothelial cells in vitro and to identify the placental factors that mediate this effect. Study design Placental-conditioned medium was generated by the culturing of normal term placental villous explants for up to 48 hours. Human umbilical vein endothelial cells were exposed to the conditioned media, and cellular proliferation, viability, and activation were investigated. Results The proliferation of endothelial cells that were exposed to 20% placental-conditioned medium was reduced by 25%, but their survival was not compromised. Conditioned medium also up-regulated the expression of E-selectin and stimulated the release of soluble intercellular adhesion molecule-1 and the secretion of interleukin-6. Treatment with interleukin-1 receptor antagonist, but not with an anti-tumor necrosis factor-α neutralizing antibody, blocked the release of soluble intercellular adhesion molecule-1 and interleukin-6. Conclusion Placentally derived interleukin-1 may be 1 of the potential mediators of the maternal inflammatory response that is observed in late pregnancy.