title: Release abilities of adenosine diphosphate from phospholipid vesicles with different membrane properties and their hemostatic effects as a platelet substitute.
abstract: We have constructed phospholipid vesicles with hemostatic activity as a platelet substitute. The vesicles were conjugated with a dodecapeptide (HHLGGAKQAGDV, H12), which is a fibrinogen γ-chain carboxy-terminal sequence (γ400-411). We have recently exploited these vesicles as a potential drug delivery system by encapsulation of adenosine 5'-diphosphate (ADP) (H12-(ADP)-vesicles). Here we explore the relationship between the ADP release from H12-(ADP)-vesicles with different membrane properties and their hemostatic effects. In total, we prepared five kinds of H12-(ADP)-vesicles with different lamellarities and membrane flexibilities. By radioisotope-labeling, we directly show that H12-(ADP)-vesicles were capable of augmenting platelet aggregation by releasing ADP in an aggregation-dependent manner. The amount of ADP released from the vesicles was dependent on their membrane properties. Specifically, the amount of ADP released increased with decreasing lamellarity and tended to increase with increasing membrane flexibility. Our in vivo results clearly demonstrated that H12-(ADP)-vesicles with the ability to release ADP exert considerable hemostatic action in terms of correcting prolonged bleeding time in a busulphan-induced thrombocytopenic rat model. We propose a recipe to control the hemostatic abilities of H12-(ADP)-vesicles by modulating ADP release based on membrane properties. We believe that this concept will be invaluable to the development of platelet substitutes and other drug carriers.
authors.affiliation: Department of Life Science and Medical Bioscience, Graduate School of Advanced Science and Engineering, Waseda University, TWIns, Tokyo 162-8480, Japan.
authors.forename: Yosuke
authors.initials: Y
authors.lastname: Okamura
authors.forename: Shunsuke
authors.initials: S
authors.lastname: Katsuno
authors.forename: Hidenori
authors.initials: H
authors.lastname: Suzuki
authors.forename: Hitomi
authors.initials: H
authors.lastname: Maruyama
authors.forename: Makoto
authors.initials: M
authors.lastname: Handa
authors.forename: Yasuo
authors.initials: Y
authors.lastname: Ikeda
authors.forename: Shinji
authors.initials: S
authors.lastname: Takeoka
mesh_terms: D000244:Adenosine Diphosphate / Q000008:administration & dosage* / Q000494:pharmacology* / Q000627:therapeutic use; D000595:Amino Acid Sequence; D000818:Animals; D001760:Bleeding Time; D001792:Blood Platelets / Q000187:drug effects; D001802:Blood Substitutes / Q000008:administration & dosage* / Q000494:pharmacology* / Q000627:therapeutic use; D006487:Hemostasis / Q000187:drug effects*; D006801:Humans; D008081:Liposomes / Q000737:chemistry* / Q000648:ultrastructure; D008297:Male; D010455:Peptides / Q000737:chemistry; D010743:Phospholipids / Q000737:chemistry; D010974:Platelet Aggregation / Q000187:drug effects; D051381:Rats; D017208:Rats, Wistar; D013921:Thrombocytopenia / Q000188:drug therapy
chemical_list: D001802:Blood Substitutes; D008081:Liposomes; D010455:Peptides; D010743:Phospholipids; D000244:Adenosine Diphosphate