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Thromb Haemost 1990; 63(01): 112-121
DOI: 10.1055/s-0038-1645696
Original Article
Schattauer GmbH Stuttgart

The Effect of Red Blood Cells on the ADP-induced Aggregation of Human Platelets in Flow Through Tubes

David N Bell
The McGill University Medical Clinic, Montreal General Hospital, and the Department of Medicine, McGill University, Montreal, Canada
,
Samira Spain
The McGill University Medical Clinic, Montreal General Hospital, and the Department of Medicine, McGill University, Montreal, Canada
,
Harry L Goldsmith
The McGill University Medical Clinic, Montreal General Hospital, and the Department of Medicine, McGill University, Montreal, Canada
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Publikationsverlauf

Received 20. Januar 1989

Accepted after revision23. Oktober 1989

Publikationsdatum:
02. Juli 2018 (online)

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Summary

The effect of red blood cells, rbc, and shear rate on the ADPinduced aggregation of platelets in whole blood, WB, flowing through polyethylene tubing was studied using a previously described technique (1). Effluent WB was collected into 0.5% glutaraldehyde and the red blood cells removed by centrifugation through Percoll. At 23°C the rate of single platelet aggregtion was upt to 9× greater in WB than previously found in platelet-rich plasma (2) at mean tube shear rates Ḡ = 41.9,335, and 1,920 s−1, and at both 0.2 and 1.0 µM ADP. At 0.2 pM ADP, the rate of aggregation was greatest at Ḡ = 41.9 s−1 over the first 1.7 s mean transit time through the flow tube, t, but decreased steadily with time. At Ḡ ≥335 s−1 the rate of aggregation increased between t = 1.7 and 8.6 s; however, aggregate size decreased with increasing shear rate. At 1.0 µM ADP, the initial rate of single platelet aggregation was still highest at Ḡ = 41.9 s1 where large aggregates up to several millimeters in diameter containing rbc formed by t = 43 s. At this ADP concentration, aggregate size was still limited at Ḡ ≥335 s−1 but the rate of single platelet aggregation was markedly greater than at 0.2 pM ADP. By t = 43 s, no single platelets remained and rbc were not incorporated into aggregates. Although aggregate size increased slowly, large aggregates eventually formed. White blood cells were not significantly incorporated into aggregates at any shear rate or ADP concentration. Since the present technique did not induce platelet thromboxane A2 formation or cause cell lysis, these experiments provide evidence for a purely mechanical effect of rbc in augmenting platelet aggregation in WB.

Keywords

Platelet aggregation - Shear rate - Red blood cells