Characterization of biochemical markers of blood-brain-barrier permeability and the functioning of the central nervous system

The content of different biomarkers in the blood and cerebrospinal fluid is one of the most informative biochemical indicators of the state of the blood-brain barrier (BBB). The neuron-specific proteins (NSPs) outside the brain may be considered as markers of a pathological process. To date, more than 120 NSPs have more or less detailed descriptions. To evaluate the state of the BBB, it is rational to use the most studied proteins, viz., the markers of neurons and astrocytes. These are the glial fibrillary acidic protein (GFAP), neuron-specific enolase (NSE), and proteins of the S100 family. They do not cross the BBB and practically cannot be detected in serum under normal conditions. When BBB permeability is compromised, NSPs penetrate into the peripheral blood and may be measured there. Vascular endothelial growth factor (VEGF) may be important for diagnostics for the evaluation of the state of a major component of the BBB, viz., the endothelial cells. Dynamic assessment of the serum levels of NSPs and the VEGF may be used to evaluate BBB resistance and the severity of CNS lesions.