title: Antithrombin reduces shedding of the endothelial glycocalyx following ischaemia/reperfusion.
abstract: OBJECTIVE
  Antithrombin is an important inhibitor of the coagulation system, additionally exerting specific anti-inflammatory effects on endothelial cells. Healthy vascular endothelium is coated by the endothelial glycocalyx, diminution of which increases capillary permeability, e.g. after ischaemia. Antithrombin is known to infiltrate the glycocalyx, binding to glycosaminoglycans, and to preserve the glycocalyx after application tumour necrosis factor-alpha. We investigated the influence of antithrombin on glycocalyx subjected to ischaemia/reperfusion.
  
  
  RESULTS
  Isolated guinea pig hearts were perfused with Krebs-Henseleit buffer (KHB). Antithrombin was applied to achieve physiological levels (1 U/mL) before inducing 20 min of ischaemia (37 degrees C). Hearts were reperfused for 20 min at constant flow (baseline perfusion pressure 70 cmH(2)O) with KHB or KHB plus 2 g% hydroxyethyl starch (130 kDa). Coronary net fluid filtration was assessed directly by measuring transudate formation on the epicardial surface. Post-ischaemic coronary release of syndecan-1 and heparan sulfate was quantified by ELISA. Hearts were perfusion-fixed to visualize the glycocalyx by electron microscopy. Ischaemia/reperfusion caused degradation of the glycocalyx, enhanced coronary perfusion pressure, and increased vascular permeability. Antithrombin significantly reduced post-ischaemic glycocalyx shedding, coronary perfusion pressure, coronary leak, and tissue oedema formation compared to untreated hearts. Additional application of colloid augmented these actions of antithrombin. Electron microscopy revealed a mostly intact glycocalyx after antithrombin treatment.
  
  
  CONCLUSIONS
  Antithrombin preserves the endothelial glycocalyx, sustaining the vascular barrier function and reducing interstitial oedema. The potentiated effect of colloid in these hearts suggests that the prevention of shedding should be of functional benefit also in vivo.
authors.affiliation: Clinic of Anesthesiology, Ludwig-Maximilians-University Munich, Nussbaumstrasse 20, 80336 Munich, Germany. daniel.chappell@med.uni-muenchen.de
authors.forename: Daniel
authors.initials: D
authors.lastname: Chappell
authors.forename: Matthias
authors.initials: M
authors.lastname: Jacob
authors.forename: Klaus
authors.initials: K
authors.lastname: Hofmann-Kiefer
authors.forename: Markus
authors.initials: M
authors.lastname: Rehm
authors.forename: Ulrich
authors.initials: U
authors.lastname: Welsch
authors.forename: Peter
authors.initials: P
authors.lastname: Conzen
authors.forename: Bernhard F
authors.initials: BF
authors.lastname: Becker
mesh_terms: D000818:Animals; D000991:Antithrombins / Q000494:pharmacology*; D002199:Capillary Permeability / Q000187:drug effects; D003331:Coronary Vessels / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D004489:Edema, Cardiac / Q000473:pathology / Q000517:prevention & control; D042783:Endothelial Cells / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D019276:Glycocalyx / Q000187:drug effects* / Q000378:metabolism / Q000648:ultrastructure; D006168:Guinea Pigs; D006895:Hydroxyethyl Starch Derivatives / Q000494:pharmacology; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D019344:Lactic Acid / Q000378:metabolism; D008297:Male; D008854:Microscopy, Electron; D015428:Myocardial Reperfusion Injury / Q000188:drug therapy* / Q000378:metabolism / Q000473:pathology; D010477:Perfusion; D010952:Plasma Substitutes / Q000494:pharmacology; D011687:Purines / Q000378:metabolism; D014527:Uric Acid / Q000378:metabolism
chemical_list: D000991:Antithrombins; D006895:Hydroxyethyl Starch Derivatives; D010952:Plasma Substitutes; D011687:Purines; D014527:Uric Acid; D019344:Lactic Acid