Transplacental Transfer of Interleukin-1 Receptor Agonist and Antagonist Following Maternal Immune Activation

Problem Prenatal exposure to inflammation increases the incidence of neonatal brain injury. This raise the question whether maternally produced cytokines, especially interleukin (IL)-1 elevated in pathological pregnancies and known to alter fetal development, can cross the placental barrier and affect the fetus directly. Method of study We addressed if IL-1 agonist/antagonist could cross the placenta. Results Radiolabelled-IL-1 injected maternally reached the fetus in minimal amount. 3% of the amount detected within the placenta was transferred into the fetal liver and less than 1% recovered in the fetal brain 30 min after the injection Importantly, transfer of IL-1 was not affected by maternal exposure to LPS. Maternal administration of IL-1 receptor antagonist also reached the fetus in low concentration. Conclusions This suggests that minimal amount of maternally produced IL-1 family members cross the placental barrier. Their negative effects are likely indirect, through their deleterious placental actions.