From spreading depolarization to blood–brain barrier dysfunction: navigating traumatic brain injury for novel diagnosis and therapy

Considerable strides in medical interventions during the acute phase of traumatic brain injury (TBI) have brought improved overall survival rates. However, following TBI, people often face ongoing, persistent and debilitating long-term complications. Here, we review the recent literature to propose possible mechanisms that lead from TBI to long-term complications, focusing particularly on the involvement of a compromised blood–brain barrier (BBB). We discuss evidence for the role of spreading depolarization as a key pathological mechanism associated with microvascular dysfunction and the transformation of astrocytes to an inflammatory phenotype. Finally, we summarize new predictive and diagnostic biomarkers and explore potential therapeutic targets for treating long-term complications of TBI. Overall survival rates for traumatic brain injury have improved, but affected individuals often experience persistent and debilitating long-term complications. In this Review, the authors discuss recent evidence for the role of spreading depolarization in the initiation of long-term pathology in traumatic brain injury, including effects on blood–brain barrier dysfunction and neuroinflammation.