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Thromb Haemost 1988; 59(03): 378-382
DOI: 10.1055/s-0038-1647499
Original Article
Schattauer GmbH Stuttgart

Endotoxin-Induced Platelet Activation in Human Whole Blood In Vitro

Gyorgy Csako
1   The Clinical Pathology Department, Clinical Center, National lnstitutes of Health, Bethesda, MD, USA
,
Eva A Suba
2   The Naval Medical Research Institute, Bethesda, MD, USA
,
Ronald J Elin
1   The Clinical Pathology Department, Clinical Center, National lnstitutes of Health, Bethesda, MD, USA
› Author Affiliations
Further Information

Publication History

Received 27 July 1987

Accepted after revision 11 January 1988

Publication Date:
29 June 2018 (online)

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Summary

The effect of purified bacterial endotoxin was studied on human platelets in vitro. In adding up to 1 μg/mL of a highly purified endotoxin, we found neither aggregation nor ATP release in heparinized or citrated human platelet-rich plasma. On the other hand, endotoxin at concentrations as low as a few ng/mL (as may be found in septic patients) caused platelet aggregation in both heparinized and citrated human whole blood, as monitored by change in impedance, free platelet count, and size. Unlike collagen, the platelet aggregation with endotoxin occurred after a long lag phase, developed slowly, and was rarely coupled with measurable release of ATP. The platelet aggregating effect of endotoxin was dose-dependent and modified by exposure of the endotoxin to ionizing radiation. Thus, the activation of human platelets by “solubilized” endotoxin in plasma requires the presence of other blood cells. We propose that the platelet effect is mediated by monocytes and/or neutrophils stimulated by endotoxin.

Keywords

Platelet aggregation - ATP release - Whole blood - Bacterial lipopolysaccharide - Ionizing radiation