title: Assaying the efficacy of dual-antiplatelet therapy: use of a controlled-shear-rate microfluidic device with a well-defined collagen surface to track dynamic platelet adhesion.
abstract: We report the development and demonstration of an assay that distinguishes the pharmacological effects of two widely used antiplatelet therapies, aspirin (COX-1 inhibitor) and clopidogrel (P2Y12 inhibitor). Whole blood is perfused through a low-volume microfluidic device in contact with a well-characterized (ellipsometry, atomic force microscopy) acid-soluble type I collagen surface. Whole human blood treated in vitro with a P2Y12 inhibitor 2-methylthioadenosine 5'-monophosphate triethylammonium salt (2-MeSAMP) extended the time to the start of platelet recruitment, i.e., platelet binding to the collagen surface. Treatment with 2-MeSAMP also slowed the rate of aggregate buildup, with an overall reduced average platelet aggregate area after 8 min of constant blood flow. A far smaller effect was observed for in vitro treatment with aspirin, for which the rate of change of surface coverage is indistinguishable from controls. In whole blood obtained from patients under treatment with dual-antiplatelet therapy (aspirin and clopidogrel), a significant extension of time to platelet recruitment was observed along with a slowed rate of aggregate buildup and an average aggregate size approximately half that of control measurements. Differentiation of the pharmacological effects of these two well-targeted antiplatelet pathways suggests a role for this assay in determining the antiplatelet effects of these and related new therapeutics in clinical settings.
authors.affiliation: Biomedical Diagnostics Institute, Royal College of Surgeons in Ireland, Dublin 2, Ireland. LUCITTM@tcd.ie
authors.forename: Margaret B
authors.initials: MB
authors.lastname: Lucitt
authors.forename: Sinead
authors.initials: S
authors.lastname: O'Brien
authors.forename: Jonathan
authors.initials: J
authors.lastname: Cowman
authors.forename: Gerardene
authors.initials: G
authors.lastname: Meade
authors.forename: Lourdes
authors.initials: L
authors.lastname: Basabe-Desmonts
authors.forename: Martin
authors.initials: M
authors.lastname: Somers
authors.forename: Nigel
authors.initials: N
authors.lastname: Kent
authors.forename: Antonio J
authors.initials: AJ
authors.lastname: Ricco
authors.forename: Dermot
authors.initials: D
authors.lastname: Kenny
mesh_terms: D001241:Aspirin / Q000008:administration & dosage*; D001681:Biological Assay / Q000295:instrumentation*; D001792:Blood Platelets / Q000187:drug effects / Q000502:physiology*; D002478:Cells, Cultured; D000077144:Clopidogrel; D003094:Collagen / Q000737:chemistry / Q000493:pharmacokinetics*; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D004353:Drug Evaluation, Preclinical / Q000295:instrumentation; D017022:Flow Injection Analysis / Q000295:instrumentation*; D006801:Humans; D010973:Platelet Adhesiveness / Q000187:drug effects / Q000502:physiology*; D010975:Platelet Aggregation Inhibitors / Q000008:administration & dosage; D033081:Shear Strength; D013499:Surface Properties; D013988:Ticlopidine / Q000008:administration & dosage / Q000031:analogs & derivatives*; D016896:Treatment Outcome
chemical_list: D004338:Drug Combinations; D010975:Platelet Aggregation Inhibitors; D003094:Collagen; D000077144:Clopidogrel; D013988:Ticlopidine; D001241:Aspirin