Limits...
Dynamic analysis of platelet deposition to resolve platelet adhesion receptor activity in whole blood at arterial shear rate.

Pugh N, Bihan D, Perry DJ, Farndale RW - Platelets (2014)

Bottom Line: On collagen, PM falls exponentially to a low level, corresponding to firm platelet adhesion, while on other substrates, PM remains high.Different receptor-specific thrombogenic surfaces reveal that the PM time constant reflects real-time changes in integrins αIIbβ3 and α2β1 activity.This ensemble kinetic analysis has the potential to provide valuable diagnostic information about platelet thrombus formation with both academic and clinical applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, University of Cambridge , Cambridge , UK .

ABSTRACT
Platelet activation is traditionally quantified using turbidimetric aggregometry, which reflects integrin αIIbβ3 activity, an important determinant of platelet function during pathophysiological thrombus formation. However, aggregometry does not recreate the shear conditions prevailing during thrombosis in vivo. Here we describe novel whole-frame analysis of real-time video microscopy to quantify platelet adhesion receptor activity under shear in parallel-plate flow chambers. We demonstrate that the rate of change of surface coverage (designated Platelet Population Mobility, PM) quantifies platelet mobility. On collagen, PM falls exponentially to a low level, corresponding to firm platelet adhesion, while on other substrates, PM remains high. Different receptor-specific thrombogenic surfaces reveal that the PM time constant reflects real-time changes in integrins αIIbβ3 and α2β1 activity. This ensemble kinetic analysis has the potential to provide valuable diagnostic information about platelet thrombus formation with both academic and clinical applications.

Show MeSH

Related in: MedlinePlus

PM quantifies platelet adhesion under flow conditions. (A) Whole blood was perfused at 1000 s−1 over type I collagen fibers (○) or VWF-III (•) and images were acquired at 0.2 Hz for 5 min. Image processing yielded PM measurements throughout the 5-min perfusion, which are plotted vs. time. PM curves were modeled as exponential decays, yielding the parameter of Plateau (B) (see Supplementary material for details). End-point image analysis yielded ZV50 (C).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
getmorefigures.php?uid=PMC4389707&req=5

Figure 1: PM quantifies platelet adhesion under flow conditions. (A) Whole blood was perfused at 1000 s−1 over type I collagen fibers (○) or VWF-III (•) and images were acquired at 0.2 Hz for 5 min. Image processing yielded PM measurements throughout the 5-min perfusion, which are plotted vs. time. PM curves were modeled as exponential decays, yielding the parameter of Plateau (B) (see Supplementary material for details). End-point image analysis yielded ZV50 (C).

Mentions: Platelet population mobility was plotted against time (Figure 1A). Using both peptide VWF-III [6] and collagen fiber substrates, PM achieved a steady state after an initial period of high platelet mobility. On collagen, PM fell rapidly from its initial value of 58.7 ± 3.6%, reaching a plateau of 9.1 ± 0.2% (Figure 1B), progressing from its initial, transient interaction to stable platelet adhesion. On VWF-III, PM was initially higher (102.4 ± 4.1%) and fell to a much higher steady state than on collagen (Plateau: 73.3 ± 1.0%), indicating that platelets interacted only transiently with this surface and did not achieve stable adhesion. This behavior indicates platelet rolling [7].


Dynamic analysis of platelet deposition to resolve platelet adhesion receptor activity in whole blood at arterial shear rate.

Pugh N, Bihan D, Perry DJ, Farndale RW - Platelets (2014)

PM quantifies platelet adhesion under flow conditions. (A) Whole blood was perfused at 1000 s−1 over type I collagen fibers (○) or VWF-III (•) and images were acquired at 0.2 Hz for 5 min. Image processing yielded PM measurements throughout the 5-min perfusion, which are plotted vs. time. PM curves were modeled as exponential decays, yielding the parameter of Plateau (B) (see Supplementary material for details). End-point image analysis yielded ZV50 (C).
© Copyright Policy - open-access
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4389707&req=5

Figure 1: PM quantifies platelet adhesion under flow conditions. (A) Whole blood was perfused at 1000 s−1 over type I collagen fibers (○) or VWF-III (•) and images were acquired at 0.2 Hz for 5 min. Image processing yielded PM measurements throughout the 5-min perfusion, which are plotted vs. time. PM curves were modeled as exponential decays, yielding the parameter of Plateau (B) (see Supplementary material for details). End-point image analysis yielded ZV50 (C).
Mentions: Platelet population mobility was plotted against time (Figure 1A). Using both peptide VWF-III [6] and collagen fiber substrates, PM achieved a steady state after an initial period of high platelet mobility. On collagen, PM fell rapidly from its initial value of 58.7 ± 3.6%, reaching a plateau of 9.1 ± 0.2% (Figure 1B), progressing from its initial, transient interaction to stable platelet adhesion. On VWF-III, PM was initially higher (102.4 ± 4.1%) and fell to a much higher steady state than on collagen (Plateau: 73.3 ± 1.0%), indicating that platelets interacted only transiently with this surface and did not achieve stable adhesion. This behavior indicates platelet rolling [7].

Bottom Line: On collagen, PM falls exponentially to a low level, corresponding to firm platelet adhesion, while on other substrates, PM remains high.Different receptor-specific thrombogenic surfaces reveal that the PM time constant reflects real-time changes in integrins αIIbβ3 and α2β1 activity.This ensemble kinetic analysis has the potential to provide valuable diagnostic information about platelet thrombus formation with both academic and clinical applications.

View Article: PubMed Central - PubMed

Affiliation: Department of Biochemistry, University of Cambridge , Cambridge , UK .

ABSTRACT
Platelet activation is traditionally quantified using turbidimetric aggregometry, which reflects integrin αIIbβ3 activity, an important determinant of platelet function during pathophysiological thrombus formation. However, aggregometry does not recreate the shear conditions prevailing during thrombosis in vivo. Here we describe novel whole-frame analysis of real-time video microscopy to quantify platelet adhesion receptor activity under shear in parallel-plate flow chambers. We demonstrate that the rate of change of surface coverage (designated Platelet Population Mobility, PM) quantifies platelet mobility. On collagen, PM falls exponentially to a low level, corresponding to firm platelet adhesion, while on other substrates, PM remains high. Different receptor-specific thrombogenic surfaces reveal that the PM time constant reflects real-time changes in integrins αIIbβ3 and α2β1 activity. This ensemble kinetic analysis has the potential to provide valuable diagnostic information about platelet thrombus formation with both academic and clinical applications.

Show MeSH
Related in: MedlinePlus