Csako G, Suba E A, Elin R J
Clinical Pathology Department, National Institutes of Health, Bethesda, MD 20892.
Thromb Haemost. 1988 Jun 16;59(3):378-82.
The effect of purified bacterial endotoxin was studied on human platelets in vitro. In adding up to 1 microgram/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.
在体外研究了纯化细菌内毒素对人血小板的作用。在添加高达1微克/毫升的高度纯化内毒素时，我们发现在肝素化或枸橼酸化的富含人血小板的血浆中既没有聚集也没有ATP释放。另一方面，浓度低至几纳克/毫升的内毒素（如在脓毒症患者中可能发现的）在肝素化和枸橼酸化的人全血中均引起血小板聚集，通过阻抗变化、游离血小板计数和大小进行监测。与胶原蛋白不同，内毒素引起的血小板聚集发生在较长的延迟期之后，发展缓慢，并且很少与可测量的ATP释放相关联。内毒素的血小板聚集作用是剂量依赖性的，并且通过将内毒素暴露于电离辐射而改变。因此，血浆中“溶解的”内毒素对人血小板的激活需要其他血细胞的存在。我们提出血小板效应是由内毒素刺激的单核细胞和/或中性粒细胞介导的。
