Department of Biochemistry, Institute of Biochemistry and Molecular Biology, Semmelweis University, Budapest, Hungary.
Biological Nanochemistry Research Group, Institute of Materials and Environmental Chemistry, Research Centre for Natural Sciences, Hungarian Academy of Sciences, Budapest, Hungary.
J Thromb Haemost. 2021 May;19(5):1307-1318. doi: 10.1111/jth.15258. Epub 2021 Feb 20.
Neutrophil extracellular traps (NETs) containing DNA and histones are expelled from neutrophils in infection and thrombosis. Heparins, anticoagulant polyanions, can neutralize histones with a potential therapeutic advantage in sepsis. Polyphosphates, procoagulant polyanions, are released by platelets and microorganisms.
To characterize the combined effects of NET components and polyanions on clot structure, mechanical properties and lytic susceptibility.
Scanning electron microscopy, pressure-driven permeation, turbidimetry, and oscillation rheometry were used for the characterization of the structure, viscoelasticity, and kinetics of formation and lysis of fibrin and plasma clots containing histones+/-DNA in combination with unfractionated heparin, its desulfated derivatives, low molecular weight heparin (LMWH), pentasaccharide, and polyphosphates of different sizes.
Histones and DNA inhibited fibrin lysis by plasmin, but this behavior was not neutralized by negatively charged heparins or short polyphosphates. Rather, fibrin lysis was further inhibited by added polyanions. Histones inhibited plasma clot lysis by tissue plasminogen activator and the response to added heparin was size dependent. Unfractionated heparin, LMWH, and pentasaccharide had no effect, exacerbated, or reversed histone inhibition, respectively. Histones increased the mechanical strength of fibrin, which was exacerbated by smaller heparin and polyphosphate molecules. Histones increased fibrin diameter and pore size of fibrin clots and this effect was neutralized by all heparin variants but enhanced by polyphosphates.
Despite their common polyanionic character, heparins and polyphosphates exert distinct effects on fibrin mechanical and fibrinolytic stability. Anti-fibrinolytic effects of histones were more often enhanced by polyanions not counteracted. Careful selection of anti-histone strategies is required if they are to be combined with thrombolytic therapy.
中性粒细胞胞外诱捕网（NETs）包含 DNA 和组蛋白，在感染和血栓形成时从中性粒细胞中释放出来。肝素作为抗凝聚阴离子，可以中和组蛋白，在败血症中具有潜在的治疗优势。多磷酸盐作为促凝聚阴离子，由血小板和微生物释放。
研究 NET 成分和聚阴离子对血栓结构、力学性能和裂解敏感性的综合影响。
采用扫描电子显微镜、压力驱动渗透、浊度测定和振荡流变学方法，对含组蛋白+/-DNA 的纤维蛋白和血浆血栓的结构、粘弹性、形成和裂解动力学进行了表征，这些血栓与未分级肝素、其硫酸化衍生物、低分子量肝素（LMWH）、戊糖和不同大小的多磷酸盐组合。
组蛋白和 DNA 抑制纤维蛋白被纤溶酶裂解，但这种行为不受带负电荷的肝素或短多磷酸盐中和。相反，添加的聚阴离子进一步抑制纤维蛋白的裂解。组蛋白抑制组织型纤溶酶原激活物对血浆血栓的裂解，而对添加肝素的反应则取决于其大小。未分级肝素、LMWH 和戊糖分别无作用、加重或逆转组蛋白的抑制作用。组蛋白增加了纤维蛋白的机械强度，而较小的肝素和多磷酸盐分子则加剧了这种作用。组蛋白增加了纤维蛋白的直径和纤维蛋白血栓的孔径，这种作用被所有肝素变体中和，但被多磷酸盐增强。
尽管肝素和多磷酸盐具有共同的聚阴离子特性，但它们对纤维蛋白力学和纤维蛋白溶解稳定性的影响却截然不同。组蛋白的抗纤维蛋白溶解作用更多地被聚阴离子增强，而不是被中和。如果要将其与溶栓治疗结合使用，则需要仔细选择抗组蛋白策略。
