Rabcuka Julija, Smethurst Peter A, Dammert Katharina, Saker Jarob, Aran Gemma, Walsh Geraldine M, Tan Joanne C G, Codinach Margarita, McTaggart Ken, Marks Denese C, Bakker Stephan J L, McMahon Amy, Di Angelantonio Emanuele, Roberts David J, Blonski Slawomir, Korczyk Piotr M, Shirakami Atsushi, Cardigan Rebecca, Swietach Pawel
Department of Physiology, Anatomy & Genetics, University of Oxford, Oxford, UK.
Component Development Laboratory, NHS Blood and Transplant, Cambridge, UK.
EBioMedicine. 2025 Jan;111:105498. doi: 10.1016/j.ebiom.2024.105498. Epub 2024 Dec 14.
Metrics evaluating the functional quality of red blood cells (RBCs) must consider their role in oxygen delivery. Whereas oxygen-carrying capacity is routinely reported using haemoglobin assays, the rate of oxygen exchange is not measured, yet also important for tissue oxygenation. Since oxygen-unloading depends on the diffusion pathlength inside RBCs, cell geometry offers a plausible surrogate.
We related the time-constant of oxygen-unloading (τ), measured using single-cell oxygen saturation imaging, with flow-cytometric variables recorded on a haematology analyser. Experiments compared freshly-drawn RBCs with stored RBCs, wherein metabolic run-down and spherical remodelling hinder oxygen unloading.
Multivariable regression related τ to a ratio of side- and forward-scatter, referred to herein as FlowScore. FlowScore was able to distinguish, with sensitivity and specificity >80%, freshly drawn blood from blood that underwent storage-related kinetic attrition in O-handling. Moreover, FlowScore predicted τ restoration upon biochemical rejuvenation of stored blood. Since RBC geometry and metabolic state are related, variants of FlowScore estimated [ATP] and [2,3-diphosphoglycerate]. The veracity of FlowScore was confirmed by four blood-banking systems (Australia, Canada, England, Spain). Applying FlowScore to data from the COMPARE study revealed a positive association with the time-delay from sample collection to measurement, which was verified experimentally. The LifeLines dataset revealed age, sex, and smoking among factors affecting FlowScore.
We establish FlowScore as a widely-accessible and cost-effective surrogate of RBC oxygen-unloading kinetics. As a metric of a cellular process that is sensitive to storage and disease, we propose FlowScore as an RBC quality marker for blood-banking and haematology.
See Acknowledgements.
评估红细胞（RBC）功能质量的指标必须考虑其在氧气输送中的作用。虽然通过血红蛋白检测常规报告携氧能力，但氧气交换速率并未测量，而这对组织氧合也很重要。由于氧气卸载取决于红细胞内的扩散路径长度，细胞几何形状提供了一个合理的替代指标。
我们将使用单细胞氧饱和度成像测量的氧气卸载时间常数（τ）与血液学分析仪记录的流式细胞术变量相关联。实验比较了新鲜抽取的红细胞与储存的红细胞，其中代谢衰退和球形重塑会阻碍氧气卸载。
多变量回归将τ与侧向散射和前向散射的比率相关联，在此称为FlowScore。FlowScore能够以大于80%的敏感性和特异性区分新鲜抽取的血液和在氧气处理中经历与储存相关的动力学损耗的血液。此外，FlowScore预测了储存血液生化复壮后τ的恢复。由于红细胞几何形状和代谢状态相关，FlowScore的变体估计了[ATP]和[2,3-二磷酸甘油酸]。四个血库系统（澳大利亚、加拿大、英国、西班牙）证实了FlowScore的准确性。将FlowScore应用于COMPARE研究的数据显示与从样本采集到测量的时间延迟呈正相关，这在实验中得到了验证。生命线数据集揭示了年龄、性别和吸烟等影响FlowScore的因素。
我们将FlowScore确立为红细胞氧气卸载动力学的一种广泛可用且经济高效的替代指标。作为对储存和疾病敏感的细胞过程的指标，我们提议将FlowScore作为血库和血液学中的红细胞质量标志物。
见致谢。
