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Blood, Vol. 107, Issue 5, 1943-1950, March 1, 2006
Size regulation of von Willebrand factor–mediated platelet thrombi by ADAMTS13 in flowing blood
Blood Donadelli et al.
107: 1943
Supplemental materials for: Donadelli et al
Files in this Data Supplement:
- Video 1. Perfusion of whole blood over immobilized VWF (MOV, 4.22 MB)
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PPACK was added to prevent clotting and mepacrine to render platelets fluorescent. Arrows indicate the direction of flow, and wall shear rates are indicated. Time shown is from the beginning of flow over the test surface.
- Video 2. Perfusion of whole blood containing EDTA followed by the same blood without EDTA (MOV, 5.6 MB)
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Experimental conditions as described for movie 1, except that blood containing 5 mM EDTA (Whole blood+EDTA) was perfused for 15 min before changing to blood without EDTA (Whole blood), as indicated. The movie is presented in real time (30 frames/s), except when noted. In this experiment, platelet clusters persist for an extended period of time in the presence of EDTA, and it can be appreciated that they are more numerous and larger when they form soon after the transition from lower to higher shear rate (compare images beginning at 2:42 min with those beginning at 4:25 and 5:36). This is because platelet capturing from flowing blood onto the surface is more efficient at lower shear rates. Platelet clusters continue to form at the higher shear rates tested (15,000 and 17,000 s-1) and their number reflects equilibrium between platelet recruitment and the opposing effects of shear forces. Note that elongated clusters with persistent adhesion to the surface, as opposed to rolling clusters, are predominant at the higher shear rate. Note also that formed platelet clusters persist in the presence of EDTA when the shear rate is decreased to 3,000 s-1, but dissipate when blood without EDTA is perfused over the surface.
- Video 3. Perfusion of washed blood cells with added soluble VWF and without or with recombinant ADAMTS-13 (MOV, 4 MB)
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Two experiments are presented concurrently. Top screen: Control (ctr), showing the perfusion of blood cells with 20 µg/ml purified VWF; bottom screen: the same, but with the addition of ADAMTS-13 (+AD; protease activity added before perfusion = 17.5% of that present in normal blood). Other conditions as described for movie 1. Note that in this experiment (performed in the absence of plasma proteins and, thus, with a perfusing fluid of lower viscosity) small platelet clusters are present already at the shear rate of 5,500 s-1.
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