Institute of Transfusion Medicine and Transplant Engineering, Hannover Medical School, Carl-Neuberg-Str. 1, D-30625 Hannover, Germany.
Department of Nephrology, Hannover Medical School, D-30625 Hannover, Germany.
Biol Chem. 2022 Sep 5;403(11-12):1091-1098. doi: 10.1515/hsz-2022-0184. Print 2022 Nov 25.
Transfusion effectiveness of red blood cells (RBCs) has been associated with duration of the storage period. Storage-dependent RBC alterations lead to hemolysis and release of toxic free heme, but the increase of free heme levels over time is largely unknown. In the current study, an apo-horseradish peroxidase (apoHRP)-based assay was applied to measure levels of free heme at regular intervals or periodically in supernatants of RBCs until a maximum storage period of 42 days. Free heme levels increased with linear time-dependent kinetics up to day 21 and accelerated disproportionally after day 28 until day 42, as determined with the apoHRP assay. Individual time courses of free heme in different RBC units exhibited high variability. Notably, levels of free hemoglobin, an established indicator of RBC damage, and those of total heme increased with continuous time-dependent linear kinetics over the entire 42 day storage period, respectively. Supernatants from RBC units with high levels of free heme led to inflammatory activation of human neutrophils. In conclusion, determining free heme in stored RBCs with the applied apoHRP assay may become feasible for testing of RBC storage quality in clinical transfusion medicine.
红细胞（RBC）的输血效果与储存时间有关。储存依赖性 RBC 改变会导致溶血和有毒游离血红素的释放，但游离血红素水平随时间的增加在很大程度上是未知的。在当前的研究中，应用脱辅基辣根过氧化物酶（apoHRP）测定法定期或定期测量 RBC 上清液中游离血红素的水平，直到最长储存期为 42 天。游离血红素水平随线性时间依赖性动力学增加，直到第 21 天，然后在第 28 天之后不成比例地加速，直到第 42 天，这是通过 apoHRP 测定法确定的。不同 RBC 单位中游离血红素的个体时间曲线表现出高度的可变性。值得注意的是，游离血红蛋白水平（RBC 损伤的既定指标）和总血红素水平随时间呈连续线性增加，分别在整个 42 天的储存期内。来自游离血红素水平较高的 RBC 单位的上清液导致人中性粒细胞的炎症激活。总之，应用apoHRP 测定法测定储存 RBC 中的游离血红素可能成为临床输血医学中 RBC 储存质量检测的可行方法。
