Kucukal Erdem, Ilich Anton, Key Nigel S, Little Jane A, Gurkan Umut A
Department of Mechanical and Aerospace Engineering, Case Western Reserve University, Cleveland, OH, USA.
Division of Hematology/Oncology, Department of Medicine, University of North Carolina, Chapel Hill, NC, USA.
Am J Hematol. 2018 Jun 15. doi: 10.1002/ajh.25159.
In sickle cell disease (SCD), 'disease severity' associates with increased RBC adhesion to quiescent endothelium, but the impact on activated endothelium is not known. Increased concentrations of free heme result from intravascular hemolysis in SCD. Heme is essential for aerobic metabolism, and plays an important role in numerous biological processes. Excess free heme induces reactive oxygen species generation and endothelial activation, which are associated with cardiovascular disorders including atherosclerosis, hypertension, and thrombosis. Here, we utilized an endothelialized microfluidic platform (Endothelium-on-a-chip) to assess adhesion of sickle hemoglobin-containing red blood cells (HbS RBCs), from adults with homozygous SCD, to heme-activated human endothelial cells (EC) in vitro. Confluent EC monolayers in microchannels were treated with pathophysiologically relevant levels of heme in order to simulate the highly hemolytic intravascular milieu seen in SCD. RBC adhesion to heme-activated ECs varied from subject to subject, and was associated with plasma markers of hemolysis (LDH) and reticulocytosis, thereby linking those RBCs that are most likely to adhere with those that are most likely to hemolyze. These results re-emphasize the critical contribution made by heterogeneous adhesive HbS RBCs to the pathophysiology of SCD. We found that adhesion of HbS RBCs to heme-activated ECs varied amongst individuals in the study population, and associated with biomarkers of hemolysis and inflammation, age, and a recent history of transfusion. Importantly, the microfluidic approach described herein holds promise as a clinically feasible Endothelium-on-a-chip platform with which to study complex heterocellular adhesive interactions in SCD. This article is protected by copyright. All rights reserved.
在镰状细胞病（SCD）中，“疾病严重程度”与红细胞对静止内皮的粘附增加有关，但对活化内皮的影响尚不清楚。SCD中的血管内溶血导致游离血红素浓度升高。血红素是有氧代谢所必需的，并且在众多生物过程中发挥重要作用。过量的游离血红素会诱导活性氧的产生和内皮激活，这与包括动脉粥样硬化、高血压和血栓形成在内的心血管疾病有关。在此，我们利用内皮化微流控平台（芯片上的内皮）来评估来自纯合子SCD成人的含镰状血红蛋白的红细胞（HbS RBCs）在体外与血红素激活的人内皮细胞（EC）的粘附。为了模拟SCD中所见的高度溶血的血管内环境，对微通道中的汇合EC单层用病理生理学相关水平的血红素进行处理。HbS RBCs与血红素激活的ECs的粘附因个体而异，并且与溶血（LDH）和网织红细胞增多的血浆标志物相关，从而将最可能粘附的那些RBC与最可能溶血的那些RBC联系起来。这些结果再次强调了异质性粘附性HbS RBCs对SCD病理生理学的关键贡献。我们发现，在研究人群中，HbS RBCs与血红素激活的ECs的粘附在个体之间存在差异，并且与溶血和炎症的生物标志物、年龄以及近期输血史相关。重要的是，本文所述的微流控方法有望成为一种临床上可行的芯片上的内皮平台，用于研究SCD中复杂的异细胞粘附相互作用。本文受版权保护。保留所有权利。
