Molecular physiology and pathophysiology of tight junctions in the blood-brain barrier

Disruption of the tight junctions (TJs) of the blood-brain barrier (BBB) is a hallmark of many CNS pathologies, including stroke, HIV encephalitis, Al zheimer's disease, multiple sclerosis and bacterial meningitis. Furthermore , systemic-derived inflammation has recently been shown to cause BBB tight junctional disruption and increased paracellular permeability. The BBB is c apable of rapid modulation in response to physiological stimuli at the cyto skeletal level, which enables it to protect the brain parenchyma and mainta in a homeostatic environment. By allowing the 'loosening' of Us and an incr ease in paracellular permeability, the BBB is able to 'bend without breakin g'; thereby, maintaining structural integrity.