Function, aging and dysfunction of blood-brain barrier. Crossing the barrier

The blood-brain barrier is an interface between the circulation and brain. It is responsible for the homeostasis of central nervous system, protection and feeding of the brain and for providing the conditions for fine regulation of neurons. The coordinated function of different cell types and the regulated expression of molecular systems make possible the functionality of blood-brain barrier. However, this complex system can be broken due to different insults with a consequence of appearance of elevated levels of unwanted exogenous and endogenous molecules in the brain involved in the pathomechanisms of several disorders. The most important risk factor for the damage of blood-brain barrier is the aging itself, which causes disruption of the barrier through DNA mutation, oxidative stress and release of inflammatory mediators. Although the physiological aging is accompanied by morphological changes, the dysfunction of membrane transporters could also lead to neurodegenerative disorders. Structure, function and breakdown of the blood-brain barrier and the possibilities to cross it, are presented.