title: The mechanisms of energy crisis in human astrocytes after subarachnoid hemorrhage.
abstract: BACKGROUND
  Calcium (Ca2+) is a cofactor of multiple cellular processes. The mechanisms that lead to elevated cytosolic Ca2+ concentration are unclear.
  
  
  OBJECTIVE
  To illuminate how bloody cerebrospinal fluid (bCSF) from patients with intraventricular hemorrhage causes cell death of cultured human astrocytes.
  
  
  METHODS
  Cultured astrocytes were incubated with bCSF. In control experiments, native CSF was used. Cytosolic Ca2+ concentration was measured by fura-2 fluorescence. Apoptosis and necrosis were evaluated by staining with Hoechst-3342 and propidium iodide.
  
  
  RESULTS
  Incubation of astrocytes with bCSF provoked a steep Ca2+ concentration peak that was followed by a slow Ca2+ rise during the observation period of 50 minutes. Necrosis, but not apoptosis, was induced. Blockade of ATP-sensitive P2 receptors with suramin inhibited the bCSF-induced initial Ca2+ peak and necrosis. Blockade of P1 receptors with 8-phenyltheophylline or of N-methyl-D-aspartate receptors with D(-)-2-amino-5-phosphopentanoic acid had no significant effect. Preincubation with xestospongin D, a blocker of inositol 1,4,5-trisphosphate receptors, prevented the initial Ca2+ rise and reduced the rate of necrosis. Preemptying of the endoplasmic reticulum with thapsigargin protected astrocytes from the bCSF-induced Ca2+ peak. Inhibition of mitochondrial permeability transition pores opening with cyclosporin A reduced the rate of astrocytic necrosis significantly, although it did not influence the initial Ca peak.
  
  
  CONCLUSIONS
  bCSF elicits a steep, transient Ca rise when administered to human astrocytes by activation of ATP-sensitive P2 receptors and subsequent inositol 1,4,5-trisphosphate-dependent Ca release from endoplasmic reticulum. This massive Ca overload leads to subsequent mitochondrial permeability transition pores opening and necrosis of the cells.
authors.affiliation: Department of Physiology, Justus Liebig University Giessen, Giessen, Germany.
authors.forename: Sascha Andreas
authors.initials: SA
authors.lastname: Kasseckert
authors.forename: Tayyab
authors.initials: T
authors.lastname: Shahzad
authors.forename: Mohammed
authors.initials: M
authors.lastname: Miqdad
authors.forename: Marco
authors.initials: M
authors.lastname: Stein
authors.forename: Yaser
authors.initials: Y
authors.lastname: Abdallah
authors.forename: Wolfram
authors.initials: W
authors.lastname: Scharbrodt
authors.forename: Matthias
authors.initials: M
authors.lastname: Oertel
mesh_terms: D000255:Adenosine Triphosphate / Q000378:metabolism; D000368:Aged; D000369:Aged, 80 and over; D017209:Apoptosis / Q000502:physiology; D001253:Astrocytes / Q000378:metabolism*; D002118:Calcium / Q000378:metabolism; D020013:Calcium Signaling / Q000502:physiology; D016923:Cell Death; D002478:Cells, Cultured; D003600:Cytosol / Q000378:metabolism; D004721:Endoplasmic Reticulum / Q000187:drug effects / Q000378:metabolism; D004734:Energy Metabolism / Q000502:physiology*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D008928:Mitochondria / Q000378:metabolism; D009336:Necrosis; D058919:Purinergic P2 Receptor Antagonists / Q000494:pharmacology; D016194:Receptors, N-Methyl-D-Aspartate / Q000037:antagonists & inhibitors; D015398:Signal Transduction / Q000502:physiology; D013345:Subarachnoid Hemorrhage / Q000134:cerebrospinal fluid / Q000378:metabolism*
chemical_list: D058919:Purinergic P2 Receptor Antagonists; D016194:Receptors, N-Methyl-D-Aspartate; D000255:Adenosine Triphosphate; D002118:Calcium