8 research outputs found
Identification of a neurovascular signaling pathway regulating seizures in mice
ObjectiveA growing body of evidence suggests that increased bloodâbrain barrier (BBB) permeability can contribute to the development of seizures. The protease tissue plasminogen activator (tPA) has been shown to promote BBB permeability and susceptibility to seizures. In this study, we examined the pathway regulated by tPA in seizures.MethodsAn experimental model of kainateâinduced seizures was used in genetically modified mice, including mice deficient in tPA (tPAâ/â), its inhibitor neuroserpin (Nspâ/â), or both (Nsp:tPAâ/â), and in mice conditionally deficient in the plateletâderived growth factor receptor alpha (PDGFRα).ResultsCompared to wildâtype (WT) mice, Nspâ/â mice have significantly reduced latency to seizure onset and generalization; whereas tPAâ/â mice have the opposite phenotype, as do Nsp:tPAâ/â mice. Furthermore, interventions that maintain BBB integrity delay seizure propagation, whereas osmotic disruption of the BBB in seizureâresistant tPAâ/â mice dramatically reduces the time to seizure onset and accelerates seizure progression. The phenotypic differences in seizure progression between WT, tPAâ/â, and Nspâ/â mice are also observed in electroencephalogram recordings in vivo, but absent in ex vivo electrophysiological recordings where regulation of the BBB is no longer necessary to maintain the extracellular environment. Finally, we demonstrate that these effects on seizure progression are mediated through signaling by PDGFRα on perivascular astrocytes.InterpretationTogether, these data identify a specific molecular pathway involving tPAâmediated PDGFRα signaling in perivascular astrocytes that regulates seizure progression through control of the BBB. Inhibition of PDGFRα signaling and maintenance of BBB integrity might therefore offer a novel clinical approach for managing seizures.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/112290/1/acn3209.pdfhttp://deepblue.lib.umich.edu/bitstream/2027.42/112290/2/acn3209-sup-0001-TableS1.pd
Imatinib treatment reduces brain injury in a murine model of traumatic brain injury
Current therapies for Traumatic brain injury (TBI) focus on stabilizing individuals and on preventing further damage from the secondary consequences of TBI. A major complication of TBI is cerebral edema, which can be caused by the loss of blood brain barrier (BBB) integrity. Recent studies in several CNS pathologies have shown that activation of latent platelet derived growth factor-CC (PDGF-CC) within the brain can promote BBB permeability through PDGF receptor α (PDGFRα) signaling, and that blocking this pathway improves outcomes. In this study we examine the efficacy for the treatment of TBI of an FDA approved antagonist of the PDGFRα, Imatinib. Using a murine model we show that Imatinib treatment, begun 45 minutes after TBI and given twice daily for 5 days, significantly reduces BBB dysfunction. This is associated with significantly reduced lesion size 24 hours, 7 days, and 21 days after TBI, reduced cerebral edema, determined from apparent diffusion co-efficient (ADC) measurements, and with the preservation of cognitive function. Finally, analysis of CSF from human TBI patients suggests a possible correlation between high PDGF-CC levels and increased injury severity. Thus, our data suggests a novel strategy for the treatment of TBI with an existing FDA approved antagonist of the PDGFRα