Mechanisms of cerebrovascular dysfunction

Cerebrovascular dysfunction characterized by the loss of endothelial integrity has been observed following ischemic and traumatic insults to the brain, resulting in the net movement of fluid and solute out of the intravascular space and into the interstitium. Following traumatic brain injury, the development of intracranial hypertension secondary to cerebral edema plays a major role in the high morbidity and mortality in these patients. Although the precise mechanisms responsible for the disruption of the normally tightly regulated cerebrovascular tissue interface remain unclear, there is increasing evidence implicating inflammatory events in this process through the transient opening of tight junctional complexes. This article will examine the interaction of astrocytes, activated neutrophils, and inflammatory mediators in inducing endothelial contraction, thereby physically opening the permeability barrier and allowing the net movement of fluid out of the intravascular space.