title: Studies of a microchip flow-chamber system to characterize whole blood thrombogenicity in healthy individuals.
abstract: BACKGROUND
  A whole blood flow-chamber system, the Total Thrombus-formation Analysis System (T-TAS), was developed for quantitative analysis of platelet thrombus formation (PTF) using microchips with thrombogenic surfaces (collagen, PL chip; collagen plus tissue thromboplastin, AR chip) under shear stress conditions. We evaluated the usefulness of the T-TAS for assessing individual thrombogenicity compared with other platelet function tests.
  
  
  METHODS
  Blood samples from 31 healthy volunteers were applied to the T-TAS to measure PTF starting time (T10: time to reach 10 kPa), occlusion time (T60 for PL chip; T80 for AR chip), and area under the curve (AUC10, area under curve until 10 min for PL chip; AUC30, 30 min for AR chip) under various shear rates (1000, 1500, 2000s(-1) for PL chip; 300 s(-1) for AR chip). Platelet functions were also tested using platelet aggregometry, the PFA-100 (collagen and epinephrine [C/EPI], collagen and adenosine diphosphate [C/ADP]), and the VerifyNow P2Y12 assay.
  
  
  RESULTS
  Individual pressure waveforms, including PTF starting and ending points, varied among healthy subjects. In the PL chip, T10 and AUC10 showed a shear-dependent correlation with C/EPI or C/ADP. VerifyNow P2Y12 values were not significantly associated with the parameters of the T-TAS. Platelet counts were correlated with all AR measurements, and mostly with PL measurements.
  
  
  CONCLUSIONS
  The results of the T-TAS were associated with those of the PFA-100 in many respects, indicating that its characteristics are related to shear-induced PTF. The T-TAS showed few correlations with platelet aggregometry and the VerifyNow P2Y12 assay. The T-TAS may allow for the measurement of comprehensive parameters of individual thrombogenicity under whole blood flow conditions.
authors.affiliation: Department of Laboratory Medicine, Keio University School of Medicine, Tokyo, Japan.
authors.forename: Yusuke
authors.initials: Y
authors.lastname: Yamaguchi
authors.forename: Takanori
authors.initials: T
authors.lastname: Moriki
authors.forename: Atsuko
authors.initials: A
authors.lastname: Igari
authors.forename: Yumiko
authors.initials: Y
authors.lastname: Matsubara
authors.forename: Tomoko
authors.initials: T
authors.lastname: Ohnishi
authors.forename: Kazuya
authors.initials: K
authors.lastname: Hosokawa
authors.forename: Mitsuru
authors.initials: M
authors.lastname: Murata
mesh_terms: D000328:Adult; D001775:Blood Circulation / Q000502:physiology; D001780:Blood Coagulation Tests / Q000295:instrumentation* / Q000379:methods; D005260:Female; D064368:Healthy Volunteers; D006801:Humans; D056656:Lab-On-A-Chip Devices; D008297:Male; D046208:Microchip Analytical Procedures / Q000379:methods; D008875:Middle Aged; D010974:Platelet Aggregation / Q000502:physiology*; D013927:Thrombosis / Q000097:blood
keywords: Flow-chamber system; Platelet; Thrombogenicity; Thrombus formation