title: Effect of remnant-like particle on shear-induced platelet activation and its inhibition by antiplatelet agents.
abstract: Remnant-like particles (RLPs) have been reported to promote atherosclerosis and to have effects on platelet function. We studied the effects of RLP on shear-induced platelet activation and their inhibition by antiplatelet agents in vitro. RLP were separated using two monoclonal antibodies, anti apo B-100 and anti apo A-I. These RLP fractions were added to whole blood (WB) or platelet-rich plasma (PRP) in serial dilution of 1, 10 or 100 microg RLP triglyceride (TG) per ml of total sample volume. These samples were incubated, and then stimulated with a high shear stress of 108 dyn/cm(2). Shear-induced platelet aggregation (SIPA) was calculated from the percentage of single platelet loss. P-selectin expression on platelet surface and platelet-derived microparticle (PMP) generation were measured before and after stimulation with shear stress using flow cytometer. SIPA was significantly enhanced by RLP in WB but not in PRP. This enhancing effect was not dose-dependent and was greatest at 10 microg TG/ml. P-selectin expression induced by shear stress was only enhanced by RLP at a concentration of 100 microg TG/ml in both WB and PRP, while generation of PMP induced by shear stress was only enhanced by RLP at a concentration of 100 microg TG/ml in WB. Aspirin inhibited only the enhancement of SIPA by RLPs, while cilostazol inhibited the enhancement of not only SIPA but also p-selectin expression and PMP generation by RLPs.
authors.affiliation: Department of Neurology, Neurological Institute, Tokyo Women's Medical University, 8-1, Kawada-cho, Shinjuku-ku, Tokyo 162-8666, Japan. myamazak@nij.twmu.ac.jp
authors.forename: Masako
authors.initials: M
authors.lastname: Yamazaki
authors.forename: Shinichiro
authors.initials: S
authors.lastname: Uchiyama
authors.forename: Yun
authors.initials: Y
authors.lastname: Xiong
authors.forename: Takamitsu
authors.initials: T
authors.lastname: Nakano
authors.forename: Tomomi
authors.initials: T
authors.lastname: Nakamura
authors.forename: Makoto
authors.initials: M
authors.lastname: Iwata
mesh_terms: D000911:Antibodies, Monoclonal / Q000378:metabolism; D001241:Aspirin / Q000494:pharmacology; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology*; D002914:Chylomicrons / Q000097:blood / Q000737:chemistry / Q000494:pharmacology*; D000077407:Cilostazol; D005434:Flow Cytometry; D006801:Humans; D008079:Lipoproteins, VLDL / Q000097:blood / Q000737:chemistry / Q000494:pharmacology*; D019007:P-Selectin / Q000187:drug effects / Q000378:metabolism; D015539:Platelet Activation / Q000187:drug effects*; D010974:Platelet Aggregation / Q000187:drug effects* / Q000502:physiology; D010975:Platelet Aggregation Inhibitors / Q000494:pharmacology; D013314:Stress, Mechanical; D013777:Tetrazoles / Q000494:pharmacology; D014280:Triglycerides / Q000494:pharmacology / Q000502:physiology
chemical_list: D000911:Antibodies, Monoclonal; D002914:Chylomicrons; D008079:Lipoproteins, VLDL; D019007:P-Selectin; D010975:Platelet Aggregation Inhibitors; D013777:Tetrazoles; D014280:Triglycerides; D000077407:Cilostazol; D001241:Aspirin