image: The connection between perturbations in BBB barrier function and damage to the astrocyte network and its functions arises from BBB damage, leading to the extravasation of albumin. In the physiological state, tight junctions of endothelial cells maintain the integrity of the BBB, preventing the infiltration of albumin from the circulation into the central nervous system (CNS). Pericytes regulate vascular constriction. Within the brain-wide perivascular space, a polarized astrocyte phenotype with AQP4 expression is essential for the functioning of the glymphatic system. When the BBB is disrupted, astrocytes are exposed to albumin from the serum. This exposure triggers the mediation of albumin uptake by astrocytes through the TGF-βR. Activation of the TGF-β pathway results in elevated levels of IL-6 and the onset of neuroinflammation. Simultaneously, endothelial cells release PGE2, which enhances astrocytic Ca2+ levels via the EP3 receptor.
Credit: ©Science China Press
The blood-brain barrier (BBB) is a barrier system separating the central nervous system from blood circulation. Connections between cells within the BBB involve specialized endothelial tight junction (TJ) proteins. BBB damage is strongly associated with numerous pathological changes in epilepsy. Endothelial cells and their TJs play a pivotal role in maintaining the BBB integrity. Astrocytes cannot directly contact endothelial cells, but the glymphatic system represents a new model to explain their relationship in epilepsy development. Leakage of albumin caused by BBB damage is a pivotal factor leading to the disruption of gap junction (GJ) function and structural abnormalities in astrocytes. Exposure to albumin from the circulation is one of the key factors in comprehending the subsequent proepileptic alterations in astrocytes resulting from BBB disruption. In addition, the imaging assessment methods used for BBB damage are discussed.
This review summarizes the association between the disruption of the BBB and the activation of astrocytes in epilepsy via alternation of GJs, highlights the role of albumin exposure in proepileptic changes in astrocytes following BBB disruption, emphasizing the connection between BBB damage and astrocyte activation in epilepsy. Albumin leakage, BBB damage, and astrocyte activation collectively influence and promote the progression and onset of epilepsy. Assessing BBB damage through imaging techniques may serve as a method to evaluate the patient's condition.
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Medicine Plus