红细胞密度作为细胞年龄标志物对聚集性的影响：拉伸流中的解离动力学
Influence of erythrocyte density on aggregability as a marker of cell age: Dissociation dynamics in extensional flow
AI总结：
本研究利用Percoll密度梯度离心和微流控拉伸流技术，发现红细胞密度与聚集体解离率强相关，较密细胞形成的聚集体更稳固，揭示了细胞衰老对聚集性的影响。
摘要：
血液流变学和微循环受红细胞（RBC）聚集的强烈影响。由于机械和膜表面特性等因素，RBC的聚集性可能发生显著变化，而这些特性受体内细胞衰老的影响。在本研究中，我们利用Percoll密度梯度离心法将健康供体的RBC分离为不同密度组分，将RBC聚集性作为其密度（细胞年龄和机械特性的标志物）的函数进行研究。我们在补充有Dextran的受控介质中，采用基于双曲微流体收缩和图像分析的拉伸流技术，并在卷积神经网络（CNN）的辅助下，检测了聚集体的解离速率。与其他技术不同，我们的微流控实验方法突出了在与微循环相关的动态流动条件下RBC聚集体的行为。结果表明，聚集体解离与细胞密度强相关，且由较密RBC组分形成的聚集体比平均细胞群形成的聚集体显著更稳固。本研究深入揭示了体内RBC衰老对其机械特性和聚集性的影响，强调了在细胞衰老背景下进一步探索RBC聚集及其对血流动力学潜在影响的重要性。此外，该技术可补充现有方法，以改进对健康和疾病状态下RBC聚集性的评估。
英文摘要：
Blood rheology and microcirculation are strongly influenced by red blood cell (RBC) aggregation. The aggregability of RBCs can vary significantly due to factors such as their mechanical and membrane surface properties, which are affected by cell aging in vivo. In this study, we investigate RBC aggregability as a function of their density, a marker of cell age and mechanical properties, by separating RBCs from healthy donors into different density fractions using Percoll density gradient centrifugation. We examine the dissociation rates of aggregates in a controlled medium supplemented with Dextran, employing an extensional flow technique based on hyperbolic microfluidic constrictions and image analysis, assisted by a convolutional neural network (CNN). In contrast to other techniques, our microfluidic experimental approach highlights the behavior of RBC aggregates in dynamic flow conditions relevant to microcirculation. Our results demonstrate that aggregate dissociation is strongly correlated with cell density and that aggregates formed from the denser fractions of RBCs are significantly more robust than those from the average cell population. This study provides insight into the effect of RBC aging in vivo on their mechanical properties and aggregability, underscoring the importance of further exploration of RBC aggregation in the context of cellular senescence and its potential implications for hemodynamics. Additionally, it suggests that this technique can complement existing methods for improved evaluation of RBC aggregability in health and disease.
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