Institute of Fundamental Medicine and Biology, Kazan Federal University, Kazan, Russian Federation.
Department of Internal Medicine, Division of Hematology and Program in Molecular Medicine, University of Utah, Salt Lake City, UT, USA.
Thromb Res. 2024 Sep;241:109092. doi: 10.1016/j.thromres.2024.109092. Epub 2024 Jul 7.
Leukocyte-platelet aggregates comprise a pathogenic link between hemostasis and immunity, but the prerequisites and mechanisms of their formation remain not understood.
To quantify the formation, composition, and morphology of leukocyte-platelet aggregates in vitro under the influence of various cellular activators.
Phorbol-12-myristate-13-acetate (PMA), lipopolysaccharide (LPS), thrombin receptor-activating peptide (TRAP-6), and adenosine diphosphate (ADP) were used as cellular activators. Flow cytometry was utilized to identify and quantify aggregates in whole human blood and platelet-rich plasma. Cell types and cellular aggregates were identified using fluorescently labeled antibodies against the appropriate cellular markers, and cell activation was assessed by the expression of appropriate surface markers. For confocal fluorescent microscopy, cell membranes and nuclei were labeled. Neutrophil-platelet aggregates were studied using scanning electron microscopy.
In the presence of PMA, ADP or TRAP-6, about 17-38 % of neutrophils and 61-77 % of monocytes formed aggregates with platelets in whole blood, whereas LPS did not induce platelet aggregation with either neutrophils or monocytes due the inability to activate platelets. Similar results were obtained when isolated neutrophils were added to platelet-rich plasma. All the cell types involved in the heterotypic aggregation expressed molecular markers of activation. Fluorescent and electron microscopy of the aggregates showed that the predominant platelet/leukocyte ratios were 1:1 and 2:1.
Formation of leukocyte-platelet aggregates depends on the nature of the cellular activator and the spectrum of its cell-activating ability. An indispensable condition for formation of leukocyte-platelet aggregates is activation of all cell types including platelets, which is the restrictive step.
白细胞-血小板聚集物构成了止血和免疫之间的致病联系，但它们的形成前提和机制仍不清楚。
在各种细胞激活剂的影响下，定量体外白细胞-血小板聚集物的形成、组成和形态。
使用佛波醇 12-肉豆蔻酸 13-乙酸酯（PMA）、脂多糖（LPS）、血栓素受体激活肽（TRAP-6）和二磷酸腺苷（ADP）作为细胞激活剂。流式细胞术用于识别和定量全血和富含血小板的血浆中的聚集物。使用针对适当细胞标志物的荧光标记抗体来识别和量化细胞类型和细胞聚集物，并通过适当的表面标志物的表达来评估细胞激活。对于共聚焦荧光显微镜，细胞膜和细胞核被标记。使用扫描电子显微镜研究中性粒细胞-血小板聚集物。
在 PMA、ADP 或 TRAP-6 的存在下，全血中约有 17-38%的中性粒细胞和 61-77%的单核细胞与血小板形成聚集物，而 LPS 由于不能激活血小板，因此不会诱导中性粒细胞或单核细胞与血小板形成聚集物。当将分离的中性粒细胞添加到富含血小板的血浆中时，也得到了类似的结果。所有参与异质聚集的细胞类型都表达了激活的分子标志物。聚集物的荧光和电子显微镜显示，血小板/白细胞的主要比例为 1:1 和 2:1。
白细胞-血小板聚集物的形成取决于细胞激活剂的性质及其细胞激活能力的范围。形成白细胞-血小板聚集物的一个必不可少的条件是包括血小板在内的所有细胞类型的激活，这是一个限制步骤。
