Traumatic Brain Injury and Blood-Brain Barrier Cross-Talk.

Traumatic brain injury, often referred to as the "silent epidemic," is a nondegenerative, non-congenital insult to the brain due to a blow or penetrating object that disrupts the function of the brain leading to permanent or temporary impairment of cognition, physical and psychosocial functions. Traumatic brain injury usually has poor prognosis for long-term treatment and is a major cause of mortality and morbidity worldwide; approximately 10 million deaths and/or hospitalizations annually are directly related to traumatic brain injury. Traumatic brain injury involves primary and secondary insults. Primary injury occurs during the initial insult, and results from direct or indirect force applied to the physical structures of the brain. Secondary injury is characterized by longer-term degeneration of neurons, glial cells, and vascular tissues due to activation of several proteases, glutamate and pro-inflammatory cytokine secretion. In addition, there is growing evidence that the blood-brain barrier is involved in the course of traumatic brain injury pathophysiology and has detrimental effects on the overall pathology of brain trauma, as will be discussed in this work.