Vascular Medicine Institute and the Division of Pulmonary, Allergy and Critical Care Medicine, University of Pittsburgh, Pittsburgh, Pennsylvania 15261, USA.
Transfusion. 2013 May;53(5):981-9. doi: 10.1111/j.1537-2995.2012.03850.x. Epub 2012 Aug 15.
The red blood cell (RBC) endothelial nitric oxide synthase (eNOS) has been shown to regulate intrinsic RBC rheologic properties, such as membrane deformability, suggesting that a functional eNOS could be important in RBC viability and function during storage. This study examines the correlation between RBC eNOS deficiency and the propensity of RBCs to hemolyze under selected stress conditions including prolonged hypothermic storage.
Fresh or stored RBCs from normal and eNOS knockout (KO) mice or from healthy human volunteers were subjected to selected hemolytic stress conditions including mechanical stress hemolysis, osmotic stress hemolysis, and oxidation stress hemolysis and evaluated during standard storage in CPDA-1 solutions.
Fresh RBCs from normal and eNOS KO mice demonstrated comparable susceptibility to hemolysis triggered by mechanical stress (mechanical fragility index 6.5 ± 0.5 in eNOS KO vs. 6.4 ± 0.4 for controls; n = 8-9), osmotic stress, and oxidative stress. Additionally, RBCs from both mouse groups exhibited similar hemolytic profile at the end of 14-day hypothermic storage, analogous to 42 days of human RBC storage. Storage of human RBCs (28 days in CPDA-1) in the presence of NOS cofactors (L-arginine and tetrahydro-L-biopterin) or inhibitor (N(5) -[imino(methylamino)methyl]-L-ornithine monoacetate) did not affect cell recovery or hemolytic response to the selected stressors.
These studies suggest that RBC eNOS does not modulate susceptibility to hemolysis in response to selected stress conditions or prolonged hypothermic storage. Other strategies to increase nitric oxide (NO) bioactivity after prolonged storage utilizing NOS-independent pathways such as the nitrate-nitrite-NO pathway may prove a more promising approach.
已证实红细胞（RBC）内皮型一氧化氮合酶（eNOS）可调节内在 RBC 流变特性，如膜变形性，表明功能性 eNOS 可能对 RBC 在储存过程中的活力和功能很重要。本研究检测 RBC eNOS 缺乏与 RBC 在选定应激条件下发生溶血的倾向之间的相关性，这些应激条件包括长时间低温储存。
正常和 eNOS 敲除（KO）小鼠或健康志愿者的新鲜或储存 RBC 分别接受机械性应激溶血、渗透性应激溶血和氧化性应激溶血等特定溶血应激条件，并在 CPDA-1 溶液中进行标准储存期间进行评估。
正常和 eNOS KO 小鼠的新鲜 RBC 对机械应激（机械脆性指数：eNOS KO 为 6.5 ± 0.5，对照为 6.4 ± 0.4；n = 8-9）、渗透性应激和氧化性应激引发的溶血具有相似的易感性。此外，两组小鼠的 RBC 在 14 天低温储存结束时表现出相似的溶血特征，类似于人类 RBC 储存 42 天。在存在 NOS 辅助因子（L-精氨酸和四氢-L-生物喋呤）或抑制剂（N(5)-[亚氨基（甲基氨基）甲基]-L-鸟氨酸单乙酸盐）的情况下，储存人类 RBC（CPDA-1 中 28 天）不会影响细胞回收率或对所选应激原的溶血反应。
这些研究表明，RBC eNOS 不能调节对选定应激条件或长时间低温储存的溶血易感性。利用非 NOS 依赖途径（如硝酸盐-亚硝酸盐-NO 途径）增加长时间储存后一氧化氮（NO）生物活性的其他策略可能是一种更有前途的方法。
