Galanakis Dennis K, Neerman-Arbez Marguerite, Brennan Stephen, Rafailovich Miriam, Hyder Luke, Travlou Oreanthi, Papadakis Emmanuel, Manco-Johnson Marilyn J, Henschen Agnes, Scharrer Inge
Stony Brook University, Stony Brook, USA.
Division of Med. Genetics, University Med. Center, Geneva, Switzerland.
Thromb Res. 2014 Jun;133(6):1115-23. doi: 10.1016/j.thromres.2014.03.026. Epub 2014 Mar 11.
Thromboelastography (TEG), a widely used clinical point of care coagulation test, is poorly understood. To investigate its fibrin determinants we used normal and variant fibrinogen isolates.
We focused mainly on the TEG maximum signal amplitude (MA), a shear modulus and clot stiffness indicator. Isolates included normal des-αC, cord, and abnormal congenital variants with amino acid substitutions or deletions that impaired fibrin polymerization. Heterophenotypic congenital isolates were from cryoprecipitate-depleted plasma owing to their more diminished clot MA than their cryoprecipitate counterparts. By colorimetric assay, the amount of fibrinogen adsorbed by untreated TEG cups was 83.5±12.4 pM/cm(2), n=18. Thrombin-induced clots were obtained at pH6.4 or 7.4, the latter containing 8mM CaCl2, and 14% afibrinogenemic plasma with and without gel-sieved platelets.
Measured by the water droplet contact angle, >90% reduction of surface hydrophobicity by exposure of TEG cup and pin to ozone plasma decreased MA by 74%. Increasing normal fibrinogen or thrombin concentrations progressively increased MA. Platelets increased MA further ~2 fold, except for ≥10 fold for des-αC clots. Examined in the absence of platelets, MA of heterophenotypic fibrin variants averaged 21%, n=15. The results imply that essential MA determinants include hydrophobic fibrinogen/fibrin adsorption and each polymerization contact site, with substantial enhancement by platelets. Also, cryoprecipitate-harvested soluble fibrinogen/fibrin complexes contained mostly normal molecules, while cryoprecipitate-depleted plasma contained mostly variant molecules. Moreover, significantly decreased MA by fibrinogen anomalies and/or low level thrombin generation can potentially impact clinical interpretation of MA.
血栓弹力图（TEG）是一种广泛应用于临床即时凝血检测的方法，但人们对其了解甚少。为了研究其纤维蛋白决定因素，我们使用了正常和变异的纤维蛋白原分离物。
我们主要关注TEG最大信号振幅（MA），它是一种剪切模量和血凝块硬度指标。分离物包括正常的去αC纤维蛋白原、脐带纤维蛋白原，以及具有氨基酸取代或缺失且损害纤维蛋白聚合的异常先天性变异体。异表型先天性分离物来自冷沉淀耗尽的血浆，因为它们的血凝块MA比其冷沉淀对应物更小。通过比色法测定，未经处理的TEG杯吸附的纤维蛋白原量为83.5±12.4 pM/cm²，n = 18。在pH6.4或7.4条件下获得凝血酶诱导的血凝块，后者含有8mM氯化钙，以及含有和不含有凝胶过滤血小板的14%无纤维蛋白原血浆。
通过水滴接触角测量，将TEG杯和针暴露于臭氧等离子体使表面疏水性降低>90%，MA降低了74%。增加正常纤维蛋白原或凝血酶浓度可使MA逐渐增加。血小板使MA进一步增加约2倍，但去αC血凝块增加≥10倍。在无血小板的情况下进行检测，异表型纤维蛋白变异体的MA平均为21%，n = 15。结果表明，MA的基本决定因素包括疏水性纤维蛋白原/纤维蛋白吸附和每个聚合接触位点，血小板可使其显著增强。此外，冷沉淀收获的可溶性纤维蛋白原/纤维蛋白复合物大多包含正常分子，而冷沉淀耗尽的血浆大多包含变异分子。此外，纤维蛋白原异常和/或低水平凝血酶生成导致的MA显著降低可能会影响MA的临床解读。
