Fig. 2

GFAP and GFAP–BDP released into ECF and blood when CNS injured. First, the figure shows GFAP–BDP is generated from GFAP when brain injured. Second, it describes how both GFAP and GFAP–BDP are released into ECF, and the later with a larger extent cascading response. Third, these two proteins diffused into the subarachnoid CSF. And then, GFAP/ GFAP–BDP either continue to follow the CSF flow through the ventricles or drain directly into the veins (Glymphatic System). Finally, these proteins enter the blood or circulation by diffusing through the BBB. Not only GFAP (blood) and GFAP–BDP (blood) can be served as biomarkers, but they can trigger autoantibody response as autoantigen or be cleared as foreign matters. ECF extracellular fluid, CNS central nervous system, CSF cerebrospinal fluid, BBB blood brain barrier