Department of Surgery, University of Maryland School of Medicine, Baltimore, MD, USA.
Fischell Department of Bioengineering, A. James Clark School of Engineering, University of Maryland, College Park, MD, USA.
Artif Organs. 2021 Jun;45(6):577-586. doi: 10.1111/aor.13874. Epub 2020 Dec 26.
High mechanical shear stresses (HMSS) can cause damage to blood, which manifests as morphologic changes, shortened life span, biochemical alterations, and complete rupture of blood cells and proteins, leading to the alterations of normal blood function. The aim of this study is to determine the state of neutrophil activation and function alterations caused by HMSS with short exposure time relevant to ventricular assist devices. Blood from healthy donors was exposed to three levels of HMSS (75Pa, 125Pa, and 175Pa) for a short exposure time (0.5 s) using our Couette-type blood-shearing device. Neutrophil activation (Mac-1, platelet-neutrophil aggregates) and surface expression levels of two key functional receptors (CD62L and CD162) on neutrophils were evaluated by flow cytometry. Neutrophil phagocytosis and transmigration were also examined with functional assays. Results showed that the expression of Mac-1 on neutrophils and platelet-neutrophil aggregates increased significantly while the level of CD62L expression on neutrophils decreased significantly after the exposure to HMSS. The Mac-1 expression progressively increased while the CD62L expression progressively decreased with the increased level of HMSS. The level of CD162 expression on neutrophils slightly increased after the exposure to HMSS, but the increase was not significant. The phagocytosis assay data revealed that the ability of neutrophils to phagocytose latex beads coated with fluorescently labeled rabbit IgG increased significantly with the increased level of HMSS. The transmigration ability of neutrophils slightly increased after the exposure to HMSS, but did not reach a significant level. In summary, HMSS with a short exposure time of 0.5 seconds could induce neutrophil activation, platelet-neutrophil aggregation, shedding of CD62L receptor, and increased phagocytic ability. However, the exposure to the three levels of HMSS did not cause a significant change in neutrophil transmigration capacity and shedding of CD162 receptor on neutrophils.
高机械剪切应力（HMSS）可导致血液损伤，表现为形态学变化、寿命缩短、生化改变以及血细胞和蛋白质的完全破裂，导致正常血液功能改变。本研究旨在确定与心室辅助装置相关的短暴露时间下 HMSS 引起的中性粒细胞激活和功能改变的状态。使用我们的科蒂尔（Couette）型血液剪切设备，将健康供者的血液暴露于三种不同水平的 HMSS（75Pa、125Pa 和 175Pa）下，暴露时间很短（0.5s）。通过流式细胞术评估中性粒细胞的激活（Mac-1、血小板-中性粒细胞聚集）和两种关键功能受体（CD62L 和 CD162）在中性粒细胞表面的表达水平。还通过功能测定检查中性粒细胞的吞噬作用和迁移。结果表明，暴露于 HMSS 后，中性粒细胞上 Mac-1 的表达和血小板-中性粒细胞聚集显著增加，而中性粒细胞 CD62L 的表达水平显著降低。Mac-1 的表达随 HMSS 水平的增加而逐渐增加，而 CD62L 的表达则逐渐降低。暴露于 HMSS 后，中性粒细胞上 CD162 的表达略有增加，但增加不显著。吞噬实验数据表明，中性粒细胞吞噬用荧光标记兔 IgG 包被的乳胶珠的能力随 HMSS 水平的增加而显著增强。暴露于 HMSS 后，中性粒细胞的迁移能力略有增加，但未达到显著水平。总之，暴露时间为 0.5 秒的短时间 HMSS 可诱导中性粒细胞激活、血小板-中性粒细胞聚集、CD62L 受体脱落和吞噬能力增强。然而，暴露于三种水平的 HMSS 并未导致中性粒细胞迁移能力和 CD162 受体脱落发生显著变化。
