title: A microchip flow-chamber system for quantitative assessment of the platelet thrombus formation process.
abstract: As the pathogenesis of arterial thrombosis often includes platelet thrombus formation (PTF), antiplatelet agents are commonly used for the prevention of thromboembolic events. Here, using a novel microchip flow-chamber system we developed to quantitatively analyze the PTF process, we evaluated the pharmacological efficacies of antiplatelet agents under different arterial shear rates. Hirudin-anticoagulated whole blood was perfused over a collagen-coated microchip at shear rates of 1000, 1500, and 2000s(-1), and PTF in the absence and presence of various antiplatelet agents was observed microscopically and quantified by measuring flow-pressure changes. The onset of PTF was measured as T(10) (time to reach 10 kPa), and AUC(10) (area under the flow pressure curve for the first 10 min) was calculated to quantify the overall stability of the formed thrombus. Aspirin and AR-C66096 (P2Y(12)-antagonist) at high concentrations (50 μM and 1000 nM, respectively) prolonged T(10) only modestly (AR-C66096>aspirin), but effectively decreased AUC(10), resulting in unstable PTF at all examined shear rates. With dual inhibition using both aspirin (25 μM) and ARC-66096 (250 nM), AUC(10) was drastically reduced. Nearly complete suppression of AUC(10) was also observed with abciximab (2 μg ml(-1)) and beraprost (PGI(2)-analog; 4 nM). Although OS-1 (GPIbα-antagonist; 100 nM) prevented complete capillary occlusion, significant amounts of microscopic thrombi were observed on the collagen surface. In contrast to abciximab and beraprost, OS-1 differentially affected PTF under higher shear conditions. Our novel analytical system is capable of distinguishing the pharmacological effects of various antiplatelet agents under physiological shear rates, suggesting that this system may aid in the determination of the appropriate type and dose of antiplatelet agent in the clinical setting.
authors.affiliation: Department of System Biology in Thromboregulation, Kagoshima University, Kagoshima 890-8520, Japan. kazuya-hosokawa@zacros.co.jp
authors.forename: Kazuya
authors.initials: K
authors.lastname: Hosokawa
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ohnishi
authors.forename: Masashi
authors.initials: M
authors.lastname: Fukasawa
authors.forename: Taro
authors.initials: T
authors.lastname: Kondo
authors.forename: Hisayo
authors.initials: H
authors.lastname: Sameshima
authors.forename: Takehiko
authors.initials: T
authors.lastname: Koide
authors.forename: Kenichi A
authors.initials: KA
authors.lastname: Tanaka
authors.forename: Ikuro
authors.initials: I
authors.lastname: Maruyama
mesh_terms: D000077284:Abciximab; D000255:Adenosine Triphosphate / Q000031:analogs & derivatives / Q000494:pharmacology; D000328:Adult; D000911:Antibodies, Monoclonal / Q000494:pharmacology; D019540:Area Under Curve; D001241:Aspirin / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects* / Q000378:metabolism; D001794:Blood Pressure; D003094:Collagen / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D011464:Epoprostenol / Q000031:analogs & derivatives / Q000494:pharmacology; D004867:Equipment Design; D005260:Female; D006801:Humans; D007140:Immunoglobulin Fab Fragments / Q000494:pharmacology; D056656:Lab-On-A-Chip Devices; D008297:Male; D018715:Microscopy, Video; D008875:Middle Aged; D010974:Platelet Aggregation / Q000187:drug effects*; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology*; D010979:Platelet Function Tests / Q000295:instrumentation*; D011237:Predictive Value of Tests; D012039:Regional Blood Flow; D013314:Stress, Mechanical; D013927:Thrombosis / Q000097:blood / Q000503:physiopathology / Q000517:prevention & control*; D013997:Time Factors
chemical_list: C092108:2-propylthio-D-beta,gamma-difluoromethylene ATP; D000911:Antibodies, Monoclonal; D007140:Immunoglobulin Fab Fragments; D010975:Platelet Aggregation Inhibitors; C048081:beraprost; D000255:Adenosine Triphosphate; D003094:Collagen; D011464:Epoprostenol; D001241:Aspirin; D000077284:Abciximab