title: Standard and low molecular weight heparin have no effect on tissue plasminogen activator induced plasma clot lysis or fibrinogenolysis.
abstract: Although heparin is often given as an adjunct to tissue plasminogen activator (t-PA), the effect of heparin on t-PA induced fibrin(ogen)olysis is controversial. To address this controversy, we examined the effects of standard and low molecular weight heparin (enoxaparine) on both t-PA induced clot lysis and t-PA mediated fibrinogenolysis in a human plasma system. Accordingly, 125I-labeled fibrin clots were incubated in t-PA containing citrated plasma in the presence or absence of these glycosaminoglycans, and the extent of thrombolysis was determined by measuring residual radioactivity of the clots, while B beta 1-42 levels were used as a specific index of fibrinogenolysis. Over a wide range of t-PA concentrations (0.1 to 1.6 micrograms/ml), neither heparin nor enoxaparine influences either t-PA induced clot lysis or t-PA mediated B beta 1-42 generation. These findings suggest that either agent could be used as an adjunct to t-PA without compromising either the thrombolytic potential of t-PA or its clot-selectivity.
authors.affiliation: Department of Medicine, McMaster University, Hamilton, Ont., Canada.
authors.forename: J I
authors.initials: JI
authors.lastname: Weitz
authors.forename: J
authors.initials: J
authors.lastname: Kuint
authors.forename: B
authors.initials: B
authors.lastname: Leslie
authors.forename: J
authors.initials: J
authors.lastname: Hirsh
mesh_terms: D004347:Drug Interactions; D005340:Fibrinogen / Q000378:metabolism*; D006493:Heparin / Q000494:pharmacology*; D006495:Heparin, Low-Molecular-Weight / Q000494:pharmacology*; D006801:Humans; D007457:Iodine Radioisotopes; D011863:Radioimmunoassay; D013927:Thrombosis / Q000188:drug therapy*; D010959:Tissue Plasminogen Activator / Q000494:pharmacology*
chemical_list: D006495:Heparin, Low-Molecular-Weight; D007457:Iodine Radioisotopes; D005340:Fibrinogen; D006493:Heparin; D010959:Tissue Plasminogen Activator