title: Glibenclamide reduces proinflammatory cytokines in an ex vivo model of human endotoxinaemia under hypoxaemic conditions.
abstract: OBJECTIVE
  In vivo application of the K(ATP)-channel blocker glibenclamide can reverse endotoxin-induced hypotension, vascular hyporeactivity and shock in experimental animals. The hypothesis of the present study is, that the drug effects might not only be based on direct inhibition of K(ATP)-channels of vascular smooth muscle cells, but might also reflect reduction of shock-induced excess proinflammatory cytokines and procoagulatory molecules produced in the blood monocytes.
  
  
  METHODS
  Human whole blood (normoxaemic or hypoxaemic) supplemented ex vivo with 100 ng/ml LPS was used to assess glibenclamide (3-100 μM) effects on IL-1 beta, IL-6, TNF-alpha, tissue factor, and plasminogen-activator-inhibitor-2 (PAI-2). Co-incubations with monocytes and erythrocytes and cytosolic calcium measurements were performed to reveal their purinergic intercellular interaction.
  
  
  RESULTS
  In heparinized blood, glibenclamide reduced LPS-induced release of IL-1 beta and TNF-alpha, tissue factor and PAI-2 mRNA in a concentration-dependent manner. When samples were subjected to strong hypoxemia using 95% N(2)/5% CO(2), these parameters became even more sensitive to the drug. No drug effect was observable in citrated blood or in isolated monocytes. IL-1 beta mRNA inhibition by glibenclamide appeared to be dependent on P2X7-receptor activation of monocytes by ATP-releasing erythrocytes during hypoxia. Cytosolic calcium values as well as the duration of calcium transients elicited by P2X7-receptor stimulation in isolated monocytes were strongly increased during hypoxia, both of which could be abolished by glibenclamide.
  
  
  CONCLUSIONS
  We conclude that the anti-inflammatory effect of glibenclamide is mainly based on the reduction of calcium entry by drug-induced depolarization of hypoxic monocytes. Thus, glibenclamide possesses a potentially beneficial shock-specific anti-inflammatory action.
authors.affiliation: Institute of Physiology, Center for Physiology and Pharmacology, Medical University of Vienna, Austria. diethart.schmid@meduniwien.ac.at
authors.forename: Diethart
authors.initials: D
authors.lastname: Schmid
authors.forename: Martin
authors.initials: M
authors.lastname: Svoboda
authors.forename: Albin
authors.initials: A
authors.lastname: Sorgner
authors.forename: Ivana
authors.initials: I
authors.lastname: Moravcevic
authors.forename: Theresia
authors.initials: T
authors.lastname: Thalhammer
authors.forename: Peter
authors.initials: P
authors.lastname: Chiba
authors.forename: Thomas
authors.initials: T
authors.lastname: Möslinger
mesh_terms: D000328:Adult; D000893:Anti-Inflammatory Agents / Q000008:administration & dosage / Q000494:pharmacology*; D002118:Calcium / Q000378:metabolism; D016207:Cytokines / Q000187:drug effects* / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D019446:Endotoxemia / Q000188:drug therapy* / Q000503:physiopathology; D005905:Glyburide / Q000008:administration & dosage / Q000494:pharmacology*; D006801:Humans; D000860:Hypoxia / Q000188:drug therapy / Q000503:physiopathology; D018836:Inflammation Mediators / Q000378:metabolism; D054086:KATP Channels / Q000037:antagonists & inhibitors; D008297:Male; D009000:Monocytes / Q000378:metabolism; D026902:Potassium Channel Blockers / Q000008:administration & dosage / Q000494:pharmacology*; D012333:RNA, Messenger / Q000378:metabolism; D058486:Receptors, Purinergic P2X7 / Q000378:metabolism; D055815:Young Adult
chemical_list: D000893:Anti-Inflammatory Agents; D016207:Cytokines; D018836:Inflammation Mediators; D054086:KATP Channels; D026902:Potassium Channel Blockers; D012333:RNA, Messenger; D058486:Receptors, Purinergic P2X7; D005905:Glyburide; D002118:Calcium