title: Targeting of plasminogen activator inhibitor 1 improves fibrinolytic therapy for tetracycline-induced pleural injury in rabbits.
abstract: Endogenous active plasminogen activator inhibitor 1 (PAI-1) was targeted in vivo with monoclonal antibodies (mAbs) that redirect its reaction with proteinases to the substrate branch. mAbs were used as an adjunct to prourokinase (single-chain [sc] urokinase [uPA]) intrapleural fibrinolytic therapy (IPFT) of tetracycline-induced pleural injury in rabbits. Outcomes of scuPA IPFT (0.25 or 0.0625 mg/kg) with 0.5 mg/kg of mouse IgG or mAbs (MA-33H1F7 and MA-8H9D4) were assessed at 24 hours. Pleural fluid (PF) was collected at 0, 10, 20, and 40 minutes and 24 hours after IPFT and analyzed for plasminogen activating (PA), uPA, fibrinolytic activities, levels of total plasmin/plasminogen, α-macroglobulin (αM), mAbs/IgG antigens, free active uPA, and αM/uPA complexes. Anti-PAI-1 mAbs, but not mouse IgG, delivered with an eightfold reduction in the minimal effective dose of scuPA (from 0.5 to 0.0625 mg/kg), improved the outcome of IPFT (P < 0.05). mAbs and IgG were detectable in PFs at 24 hours. Compared with identical doses of scuPA alone or with IgG, treatment with scuPA and anti-PAI-1 mAbs generated higher PF uPA amidolytic and PA activities, faster formation of αM/uPA complexes, and slower uPA inactivation. However, PAI-1 targeting did not significantly affect intrapleural fibrinolytic activity or levels of total plasmin/plasminogen and αM antigens. Targeting PAI-1 did not induce bleeding, and rendered otherwise ineffective doses of scuPA able to improve outcomes in tetracycline-induced pleural injury. PAI-1-neutralizing mAbs improved IPFT by increasing the durability of intrapleural PA activity. These results suggest a novel, well-tolerated IPFT strategy that is tractable for clinical development.
authors.affiliation: 1 Texas Lung Injury Institute of the University of Texas Health Science Center at Tyler, Tyler, Texas.
authors.forename: Galina
authors.initials: G
authors.lastname: Florova
authors.forename: Ali
authors.initials: A
authors.lastname: Azghani
authors.forename: Sophia
authors.initials: S
authors.lastname: Karandashova
authors.forename: Chris
authors.initials: C
authors.lastname: Schaefer
authors.forename: Kathleen
authors.initials: K
authors.lastname: Koenig
authors.forename: Kris
authors.initials: K
authors.lastname: Stewart-Evans
authors.forename: Paul J
authors.initials: PJ
authors.lastname: Declerck
authors.forename: Steven
authors.initials: S
authors.lastname: Idell
authors.forename: Andrey A
authors.initials: AA
authors.lastname: Komissarov
mesh_terms: D000818:Animals; D058846:Antibodies, Monoclonal, Murine-Derived / Q000494:pharmacology / Q000627:therapeutic use; D004305:Dose-Response Relationship, Drug; D004353:Drug Evaluation, Preclinical; D005260:Female; D005343:Fibrinolytic Agents / Q000494:pharmacology* / Q000627:therapeutic use; D017395:Plasminogen Activator Inhibitor 1 / Q000276:immunology; D010995:Pleural Diseases / Q000139:chemically induced / Q000188:drug therapy*; D011817:Rabbits; D015842:Serine Proteinase Inhibitors / Q000494:pharmacology* / Q000627:therapeutic use; D013752:Tetracycline
chemical_list: D058846:Antibodies, Monoclonal, Murine-Derived; D005343:Fibrinolytic Agents; D017395:Plasminogen Activator Inhibitor 1; D015842:Serine Proteinase Inhibitors; D013752:Tetracycline
keywords: animal model; fibrinolytic therapy; monoclonal antibodies; plasminogen activator inhibitor 1; prourokinase