title: Modulation of peripheral cytotoxic cells and ictogenesis in a model of seizures.
abstract: OBJECTIVE
  A link between seizure susceptibility, blood-brain barrier (BBB) failure, and the activation of peripheral white blood cells has been recently proposed. However, the molecular players involved in this cascade of events are unknown. We tested the hypothesis that immunosupression by splenectomy or lack of perforin, a downstream factor of natural killer (NK) and cytotoxic T cells, could reduce seizure onset.
  
  
  METHODS
  Pilocarpine was used to induce seizures in adult rats wild-type and perforin-deficient mice. Splenectomy was performed prior to pilocarpine injection. Seizure onset was evaluated by electroencephalography (EEG) and joint time-frequency analysis. Spleens from control and pilocarpine-treated groups were analyzed for anatomical changes and CD3+ cell content. BBB damage was assessed by measuring albumin parenchymal extravasation. Fluorescence-activated cell sorting (FACS) analysis was performed on spleen and brain tissue of wild-type and perforin-deficient mice treated, or not, with pilocarpine.
  
  
  RESULTS
  Splenectomy significantly reduced seizure-associated mortality. Histologic analysis of the spleens exposed to pilocarpine revealed altered white and red pulp anatomy and an increase in CD3+ T cells. Onset of status epilepticus (SE) and mortality were significantly decreased in perforin-deficient mice. Pilocarpine significantly increased spleen NK 1.1 and CD8+ cell percentage; in contrast, the brain inflammatory cell profile remained unchanged at the time of pilocarpine SE. BBB damage was reduced in the perforin-deficient pilocarpine-treated mice.
  
  
  CONCLUSIONS
  Immunosuppressant maneuvers such as splenectomy or lack of perforin decrease the onset or the severity of pilocarpine SE. Our results suggest that cytotoxic lymphocytes, and specifically the cytolytic factor perforin, may be key molecular players involved in the axis between peripheral intravascular inflammation and seizures.
authors.affiliation: Department of Cell Biology, Cleveland Clinic Foundation, Cleveland, Ohio 44195, USA.
authors.forename: Nicola
authors.initials: N
authors.lastname: Marchi
authors.forename: Aaron J
authors.initials: AJ
authors.lastname: Johnson
authors.forename: Vikram
authors.initials: V
authors.lastname: Puvenna
authors.forename: Holly L
authors.initials: HL
authors.lastname: Johnson
authors.forename: William
authors.initials: W
authors.lastname: Tierney
authors.forename: Chaitali
authors.initials: C
authors.lastname: Ghosh
authors.forename: Luca
authors.initials: L
authors.lastname: Cucullo
authors.forename: Paolo F
authors.initials: PF
authors.lastname: Fabene
authors.forename: Damir
authors.initials: D
authors.lastname: Janigro
mesh_terms: D000818:Animals; D015703:Antigens, CD / Q000378:metabolism; D001812:Blood-Brain Barrier / Q000187:drug effects / Q000473:pathology; D001921:Brain / Q000473:pathology; D004195:Disease Models, Animal; D004569:Electroencephalography; D005434:Flow Cytometry / Q000379:methods; D008297:Male; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D054353:Perforin / Q000172:deficiency; D010862:Pilocarpine; D051381:Rats; D017207:Rats, Sprague-Dawley; D012640:Seizures / Q000139:chemically induced / Q000209:etiology* / Q000473:pathology* / Q000628:therapy; D013156:Splenectomy / Q000379:methods; D013602:T-Lymphocytes, Cytotoxic / Q000187:drug effects / Q000502:physiology*
chemical_list: D015703:Antigens, CD; D010862:Pilocarpine; D054353:Perforin