Hemostatic Effects of Phospholipid Vesicles Carrying Fibrinogen γ Chain Dodecapeptide in Vitro and in Vivo

• Published in: Bioconjugate chemistry Vol. 16; no. 6; pp. 1589 - 1596
• Main Authors: Okamura, Yosuke, Maekawa, Ippei, Teramura, Yuji, Maruyama, Hitomi, Handa, Makoto, Ikeda, Yasuo, Takeoka, Shinji
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 01.11.2005
• Subjects: Animals; Biochemistry; Blood; Blood Coagulation - drug effects; Drug Delivery Systems; Fibrinogen - chemistry; Gene expression; Half-Life; Hemostasis - drug effects; Hemostatics - chemical synthesis; Hemostatics - pharmacokinetics; Hemostatics - pharmacology; Peptide Fragments - administration & dosage; Peptide Fragments - pharmacokinetics; Peptide Fragments - pharmacology; Phospholipids - chemistry; Phospholipids - pharmacokinetics; Phospholipids - pharmacology; Platelet Activation - drug effects; Platelet Adhesiveness - drug effects; Platelet Glycoprotein GPIIb-IIIa Complex - metabolism; Polyethylene Glycols - chemistry; Rats; Thrombocytopenia - drug therapy; Thrombosis - chemically induced
• ISSN: 1043-1802; 1520-4812
• DOI: 10.1021/bc050178g

We studied prototypes of platelet substitutes that bear on their surface a dodecapeptide, HHLGGAKQAGDV (H12). The peptide is a fibrinogen γ chain carboxy-terminal sequence (γ400−411) and recognizes specifically the active form of glycoprotein (GP) IIb/IIIa on the surface of activated platelets. We conjugated H12 to the end of poly(ethylene glycol) chains on the surface of a phospholipid vesicle with an average diameter of 220 nm to prepare H12−PEG−vesicles. The half-life of the H12−PEG−vesicles was significantly prolonged by PEG modification, and the ability of H12 on the surface of the vesicle to recognize GPIIb/IIIa was maintained even though the surface was modified with PEG chains. The H12−PEG−veiscles enhanced the in vitro thrombus formation of platelets that were adhering to a collagen-immobilized plate, when thrombocytopenia-imitation blood was passed over the plate. Based on the flow cytometric analyses of PAC-1 binding and P-selectin expression, the H12−PEG−vesicles were shown not to cause platelet activation. Furthermore, the H12−PEG−vesicles dose-dependently shortened the tail bleeding time of thrombocytopenic rats. It was confirmed that the H12−PEG−vesicles had a hemostatic effect and may be a suitable candidate for an alternative to human platelet concentrates transfused into thrombocytopenic patients.