title: Antithrombin and heparin cofactor II-mediated inactivation of alpha-thrombin by a synthetic, sulfated mannogalactan.
abstract: BACKGROUND
  A mannogalactan from Pleurotus ostreatoroseus (MgPr) was chemically sulfated to give MgPr-S1, which was evaluated for its anticoagulant and antithrombotic activities, bleeding tendency, and platelet aggregation.
  
  
  METHODS
  MgPr-S1 was partially characterized by HPSEC-MALLS, methylation analysis, and 13C NMR spectroscopy. Its anticoagulant activity was determined by assays of aPTT, TT, alpha-thrombin and factor Xa residual activity, heparin cofactor II (HCII)-, or antithrombin (AT)-mediated inhibition. The antithrombotic effect was evaluated in rats using a venous thrombosis model and the bleeding tendency was also tested in vivo. Platelet aggregation was investigated by an adaptation of the method of Born [1].
  
  
  RESULTS
  The hydroxyl groups of beta-D-Manp units and OH-2 and OH-4 of the (1-->6)-linked alpha-D-Galp units were preferentially substituted. The anticoagulant activity of MgPr-S1 was mainly by thrombin inhibition with antithrombin and HCII, and had an effect on platelet aggregation induced by ADP and alpha-thrombin. It almost completely inhibited thrombus formation in vivo at a dose of 6 mg/kg and heparin inhibited thrombus formation at a dose of 0.200 mg/kg.
  
  
  CONCLUSIONS
  These results suggested that the chemically sulfated mannogalactan could act as an alternative to heparin as anticoagulant.
authors.affiliation: Laboratório de Química de Carboidratos, Departamento de Bioquímica e Biologia Molecular, Universidade Federal do Paraná, Curitiba, Paraná, Brazil.
authors.forename: Ana Helena P
authors.initials: AH
authors.lastname: Gracher
authors.forename: Thales R
authors.initials: TR
authors.lastname: Cipriani
authors.forename: Elaine R
authors.initials: ER
authors.lastname: Carbonero
authors.forename: Philip A J
authors.initials: PA
authors.lastname: Gorin
authors.forename: Marcello
authors.initials: M
authors.lastname: Iacomini
mesh_terms: D000818:Animals; D000925:Anticoagulants / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity; D058833:Antithrombin Proteins / Q000378:metabolism*; D001760:Bleeding Time; D001777:Blood Coagulation / Q000187:drug effects*; D002850:Chromatography, Gel; D004195:Disease Models, Animal; D004305:Dose-Response Relationship, Drug; D015951:Factor Xa / Q000378:metabolism; D065427:Factor Xa Inhibitors; D005260:Female; D005343:Fibrinolytic Agents / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity; D005685:Galactans / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity; D006470:Hemorrhage / Q000139:chemically induced; D015844:Heparin Cofactor II / Q000378:metabolism*; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D008297:Male; D010314:Partial Thromboplastin Time; D010974:Platelet Aggregation / Q000187:drug effects; D020076:Pleurotus / Q000737:chemistry; D011517:Prothrombin Time; D051381:Rats; D017208:Rats, Wistar; D012542:Scattering, Radiation; D013329:Structure-Activity Relationship; D013431:Sulfates / Q000302:isolation & purification / Q000494:pharmacology* / Q000633:toxicity; D013917:Thrombin / Q000037:antagonists & inhibitors* / Q000378:metabolism; D020246:Venous Thrombosis / Q000097:blood / Q000517:prevention & control
chemical_list: D000925:Anticoagulants; D058833:Antithrombin Proteins; D065427:Factor Xa Inhibitors; D005343:Fibrinolytic Agents; D005685:Galactans; D013431:Sulfates; D015844:Heparin Cofactor II; D013917:Thrombin; D015951:Factor Xa