Blood–brain barrier dysfunction in brain diseases: Clinical experience

Summary The blood–brain barrier, a unique feature of the cerebral vasculature, is gaining attention as a feature in common neurologic disorders including stroke, traumatic brain injury, epilepsy, and schizophrenia. Although acute blood–brain barrier dysfunction can induce cerebral edema, seizures, or neuropsychiatric symptoms, epileptogenesis and cognitive decline are among the chronic effects. The mechanisms underlying blood–brain barrier dysfunction are diverse and may range from physical endothelial damage in traumatic brain injury to degradation of extracellular matrix proteins via matrix metalloproteinases as part of an inflammatory response. Clinically, blood–brain barrier dysfunction is often detected using contrast‐enhanced imaging. However, these techniques do not give any insights into the underlying mechanism. Elucidating the specific pathways of blood–brain barrier dysfunction at different time points and in different brain diseases using novel imaging techniques promises a more accurate blood–brain barrier terminology as well as new treatment options and personalized treatment.