A question of cytokine signaling in the fetus.

The study by Sadowska and colleagues, featured in this edition of Journal of Cerebral Blood Flow and Metabolism, provides compelling insight into a critical mechanism of signaling that links somatic and brain inflammatory pathways. Brain inflammation is often treated as an isolated event, but the work by Sadowska et al clearly demonstrate that interleukin 1β crosses the fetal blood brain barrier, and that the rate of transfer increases after cerebral ischemia. It is, perhaps, time to link blood-borne cytokine signaling with alterations in the course of fetal brain development, especially after transient fetal hypoxia.