Brain endothelial cell production of a neuroprotective cytokine, interleukin-6, in response to noxious stimuli

Brain endothelial cells (BECs), specialized cells of the blood-brain barrie r (BBB), are ideally positioned to monitor and respond to events in the per iphery. The present study examined their potential role in transducing immu ne signals to the brain and in responding to noxious stimuli. BECs were iso lated from rhesus monkeys at 3 age points (fetal/neonatal, adult, and very old animals). Cells were then challenged in vitro with either an immune sti mulus (interleukin-1 beta (IL-1 beta), or lipopolysaccharide (LPS)) or an o xidative challenge (hypoxia). BECs released interleukin-6 (IL-6), which is known to have neurotrophic and neuroprotective functions. Furthermore, high er amounts of IL-6 were released in both baseline and stimulated conditions by BECs derived from aged animals. This research indicates a pathway where by immune signals may be communicated to the CNS and has revealed one way t hat the BBB may protect neuronal survival under challenge conditions. (C) 1 999 Elsevier Science B.V. All rights reserved.