What has inflammation to do with traumatic brain injury?

Inflammation is an stereotypical response to tissue damage and has been extensively documented in experimental and clinical traumatic brain injury (TBI), including children. The initiation and orchestration of inflammation in TBI, as in other tissues, is complex and multifactorial encompassing pro- and anti-inflammatory cytokines, chemokines, adhesion molecules, complement factors, reactive oxygen and nitrogen species, and other undefined factors. It is evident that inflammation can have both beneficial and detrimental effects in TBI, but the mechanisms underlying this dichotomy are mostly unknown. Modification of the inflammatory response may be neuroprotective. Monitoring inflammation is now possible with techniques such as microdialysis; however, the prognostic value of measuring inflammatory mediators in TBI is still unclear with conflicting reports. Except for corticosteroids, no anti-inflammatory agents have been tested in TBI, and the negative results with these may have been flawed by their multiple side effects. Clinical trials with anti-inflammatory agents that target multiple or central and downstream pathways are warranted in adult and pediatric TBI. This review examines the mechanisms of inflammation after TBI, monitoring, and possible routes of intervention.