title: Partially desulfated heparin modulates the interaction between anti-protamine/heparin antibodies and platelets.
abstract: Protamine (PRT) is the standard drug to neutralise heparin. PRT/heparin complexes induce an immune response similar to that observed in heparin-induced thrombocytopenia (HIT). Partially desulfated heparin (ODSH) was shown to interfere with anti-platelet factor 4/heparin antibodies (Abs), which are responsible for HIT. In this study, we analyse the impact of ODSH on the interaction between anti-PRT/heparin Abs and platelets. The ability of ODSH to prevent anti-PRT/heparin Ab-induced platelet destruction in vivo was investigated using the NOD/SCID mouse model. ODSH improved platelet survival in the presence of PRT, heparin and anti-PRT/heparin Abs (median platelet survival after 300 minutes (min) with 20 µg/ml ODSH: 75%, range 70-81% vs without ODSH: 49%, range 44-59%, p=0.006). Furthermore, when ODSH was applied 60 min after Ab injection platelet survival was improved (median platelet survival after 300 min with ODSH: 83%, range 77-93% vs without ODSH: 59%, range 29-61%, p=0.02). In in vitro experiments ODSH inhibited platelet activation at concentrations >16 µg/mL (p<0.001), as well as PRT/heparin complex binding to platelets (mean fluorescence intensity [MFI] without ODSH: 85 ± 14 vs with ODSH: 15 ± 0.6, p=0.013). ODSH also displaced pre-bound complexes from the platelet surface (MFI without ODSH: 324 ± 43 vs with 32 µg/ml ODSH: 53 ± 9, p<0.001). While interfering with platelet activation by anti-PRT/heparin Abs, up to a concentration of 16 µg/ml, ODSH had only minimal impact on neutralisation of heparin by PRT. In conclusion, our study shows that ODSH is able to inhibit platelet activation and destruction suggesting a potential clinical use to reduce anti-PRT/heparin Ab-mediated adverse effects.
authors.forename: Rabie
authors.initials: R
authors.lastname: Jouni
authors.forename: Heike
authors.initials: H
authors.lastname: Zöllner
authors.forename: Ahmad
authors.initials: A
authors.lastname: Khadour
authors.forename: Jan
authors.initials: J
authors.lastname: Wesche
authors.forename: Anne
authors.initials: A
authors.lastname: Grotevendt
authors.forename: Sven
authors.initials: S
authors.lastname: Brandt
authors.forename: Mihaela
authors.initials: M
authors.lastname: Delcea
authors.forename: Krystin
authors.initials: K
authors.lastname: Krauel
authors.forename: Hansjörg
authors.initials: H
authors.lastname: Schwertz
authors.forename: Ulrich J
authors.initials: UJ
authors.lastname: Sachs
authors.forename: Andreas
authors.initials: A
authors.lastname: Greinacher
authors.affiliation: Tamam Bakchoul, MD, Institute for Immunology and Transfusion Medicine, Universitätsmedizin Greifswald, Ferdinand-Sauerbruch-Straße, 17475 Greifswald, Germany, Tel.: +49 3834 865458, Fax: +49 3834 865489, E-mail: bakchoult@uni-greifswald.de.
authors.forename: Tamam
authors.initials: T
authors.lastname: Bakchoul
mesh_terms: D000818:Animals; D000906:Antibodies / Q000737:chemistry*; D000925:Anticoagulants / Q000009:adverse effects; D001792:Blood Platelets / Q000378:metabolism*; D002470:Cell Survival; D004305:Dose-Response Relationship, Drug; D005260:Female; D006493:Heparin / Q000737:chemistry*; D006801:Humans; D007074:Immunoglobulin G / Q000737:chemistry; D008297:Male; D051379:Mice; D016688:Mice, Inbred NOD; D016513:Mice, SCID; D023421:Models, Animal; D015539:Platelet Activation / Q000187:drug effects; D010978:Platelet Factor 4 / Q000276:immunology; D011479:Protamines / Q000276:immunology*; D013921:Thrombocytopenia / Q000139:chemically induced
chemical_list: D000906:Antibodies; D000925:Anticoagulants; D007074:Immunoglobulin G; D011479:Protamines; D010978:Platelet Factor 4; D006493:Heparin
keywords: Thrombocytopenia; animal models; heparins; platelet immunology