Peshkova Alina D, Rednikova Ekaterina K, Khismatullin Rafael R, Kim Oleg V, Muzykantov Vladimir R, Purohit Prashant K, Litvinov Rustem I, Weisel John W
Department of Pharmacology, University of Pennsylvania School of Medicine, Philadelphia, PA.
Department of Cell and Developmental Biology, University of Pennsylvania School of Medicine, Philadelphia, PA.
Blood Adv. 2025 Jul 22;9(14):3418-3428. doi: 10.1182/bloodadvances.2024015533.
Platelet-driven blood clot contraction (retraction) is important for hemostasis and thrombosis. Red blood cells (RBCs) occupy approximately half of the clot volume, but their possible active contribution to contraction is unknown. The work was aimed at elucidating the ability of RBCs to promote clot shrinkage. To distinguish the effects of platelets and RBCs, we formed thrombin-induced clots from reconstituted human samples containing platelet-free plasma and platelet-depleted RBCs, followed by tracking the clot size. The clots before and after RBC-induced shrinkage were analyzed using histology and scanning electron microscopy. Tension developed in the RBC-containing plasma clots was measured with rheometry, and theoretical modeling was used to elucidate the clot shrinkage mechanisms. Platelet-depleted clots formed in the presence of RBCs exhibited >20% volume shrinkage within one hour. This process was insensitive to blebbistatin, latrunculin A, and abciximab. At a higher RBC count, clot shrinkage increased, whereas in the absence of RBCs no plasma clot shrinkage was observed. At low platelet counts, RBCs stimulated clot contraction proportionately to the platelet level. Inside the shrunken clots, RBCs formed aggregates. The average tensile force per 1 RBC was ∼120 ± 100 pN. Clots from purified fibrinogen formed in the presence of RBCs did not change in size, but underwent shrinkage in the presence of osmotically active dextran. Blood clot shrinkage can be caused by RBCs alone, and this effect is because of the RBC aggregation driven mainly by osmotic depletion. The RBC-induced clot shrinkage may reinforce platelet-driven blood clot contraction and promote clot compaction when there are few and/or dysfunctional platelets.
血小板驱动的血凝块收缩（回缩）对于止血和血栓形成至关重要。红细胞（RBC）约占血凝块体积的一半，但其对收缩可能的积极作用尚不清楚。这项研究旨在阐明红细胞促进血凝块收缩的能力。为了区分血小板和红细胞的作用，我们用不含血小板的血浆和去除血小板的红细胞重构人样本形成凝血酶诱导的血凝块，然后跟踪血凝块大小。使用组织学和扫描电子显微镜分析红细胞诱导收缩前后的血凝块。用流变学测量含红细胞血浆血凝块中产生的张力，并使用理论模型阐明血凝块收缩机制。在红细胞存在下形成的去除血小板的血凝块在一小时内体积收缩超过20%。这个过程对blebbistatin、latrunculin A和阿昔单抗不敏感。在较高的红细胞计数下，血凝块收缩增加，而在没有红细胞的情况下未观察到血浆血凝块收缩。在低血小板计数时，红细胞刺激血凝块收缩与血小板水平成比例。在收缩的血凝块内部，红细胞形成聚集体。每个红细胞的平均张力约为120±100皮牛。在红细胞存在下由纯化纤维蛋白原形成的血凝块大小不变，但在有渗透活性葡聚糖存在时会收缩。血凝块收缩可单独由红细胞引起，这种作用是由于主要由渗透耗竭驱动的红细胞聚集。当血小板数量少和/或功能异常时，红细胞诱导的血凝块收缩可能增强血小板驱动的血凝块收缩并促进血凝块压实。
