The etiological role of blood-brain barrier dysfunction in seizure disorders

Kollidon VA64, a membrane-resealing agent, reduces histopathology and improves functional outcome after controlled cortical impact in mice

Loss of plasma membrane integrity is a feature of acute cellular injury/death in vitro and in vivo. Plasmalemma-resealing agents are protective in acute central nervous system injury models, but their ability to reseal cell membranes in vivo has not been reported. Using a mouse controlled cortical impact (CCI) model, we found that propidium iodide-positive (PI+) cells pulse labeled at 6, 24, or 48 hours maintained a degenerative phenotype and disappeared from the injured brain by 7 days, suggesting that plasmalemma permeability is a biomarker of fatal cellular injury after CCI. Intravenous or intracerebroventricular administration of Kollidon VA64, poloxamer P188, or polyethylene glycol 8000 resealed injured cell membranes in vivo (P<0.05 versus vehicle or poloxamer P407). Kollidon VA64 (1 mmol/L, 500 μL) administered intravenously to mice 1  hour after CCI significantly reduced acute cellular degeneration, chronic brain tissue damage, brain edema, blood-brain barrier damage, and postinjury motor deficits (all P<0.05 versus vehicle). However, VA64 did not rescue pulse-labeled PI+ cells from eventual demise. We conclude that PI permeability within 48 hours of CCI is a biomarker of eventual cell death/loss. Kollidon VA64 reduces secondary damage after CCI by mechanisms other than or in addition to resealing permeable cells.

S100B proteins in febrile seizures

S100B protein concentrations correlate with the severity and outcome of brain damage after brain injuries, and have been shown to be markers of blood-brain barrier damage. In children elevated S100B values are seen as a marker of damage to astrocytes even after mild head injuries. S100B proteins may also give an indication of an ongoing pathological process in the brain with respect to febrile seizures (FS) and the likelihood of their recurrence. To evaluate this, we measured S100B protein concentrations in serum and cerebrospinal fluid from 103 children after their first FS. 33 children with acute infection without FS served as controls for the serum concentrations. In the FS patients the mean S100B concentration in the cerebrospinal fluid samples was 0.21 μg/L and that in the serum samples 0.12 μg/L. The mean serum concentration in the controls was 0.11 μg/L (difference 0.01 μg/L, 95% confidence interval -0.02 to 0.04 μg/L, P = 0.46). There was a correlation between age and serum S100B concentration (r = -0.28, P = 0.008) in children under four years, but S100B concentrations did not predict the clinical severity of the FS nor their recurrence. There was no correlation between time of arrival at the hospital after FS and S100B concentration in serum (r = -0.130, P = 0.28) or in cerebrospinal fluid samples (r=-0.091, P = 0.52). Our findings indicate that FS does not cause significant blood-brain barrier openings, and increase the evidence that these seizures are relatively harmless for the developing brain.