Chang Alex L, Kim Young, Seitz Aaron P, Schuster Rebecca M, Lentsch Alex B, Pritts Timothy A
Department of Surgery, University of Cincinnati, Cincinnati, Ohio.
Shock. 2017 May;47(5):632-637. doi: 10.1097/SHK.0000000000000780.
Erythrocyte-derived microparticles (MPs) are sub-micrometer, biologically active vesicles shed by red blood cells as part of the biochemical changes that occur during storage. We hypothesized that MPs from stored red blood cells would activate endothelial cells. MPs from aged murine packed red blood cells (pRBCs) were isolated and used to treat confluent layers of cultured endothelial cells. Endothelial expression of leukocyte adhesion molecules, endothelial-leukocyte adhesion molecule-1 (ELAM-1) and intercellular adhesion molecule-1(ICAM-1), and inflammatory mediator, interleukin-6 (IL-6), was evaluated at 0.5, 6, 12, and 24 h of treatment. Healthy C57BL/6 mice were transfused with a MP suspension and lung sections were analyzed for adhesion molecules and sequestered interstitial leukocytes. Increased levels of ELAM-1 and ICAM-1 were found on cultured endothelial cells 6 h after MP stimulation (6.91 vs. 4.07 relative fluorescent intensity [RFI], P < 0.01, and 5.85 vs. 3.55 RFI, P = 0.01, respectively). IL-6 in cell culture supernatants was increased after 12 h of MP stimulation compared with controls (1.24 vs. 0.73 ng/mL, P = 0.03). In vivo experiments demonstrated that MP injection increased ELAM-1 and ICAM-1 expression at 1 h (18.56 vs. 7.08 RFI, P < 0.01, and 23.66 vs. 6.87 RFI, P < 0.01, respectively) and caused increased density of pulmonary interstitial leukocytes by 4 h of treatment (69.25 vs. 29.25 cells/high powered field, P < 0.01). This series of experiments supports our hypothesis that erythrocyte-derived MPs are able to activate pulmonary endothelium, leading to the pulmonary sequestration of leukocytes following the transfusion of stored pRBCs.
红细胞衍生的微粒（MPs）是红细胞脱落的亚微米级生物活性囊泡，是储存期间发生的生化变化的一部分。我们假设储存红细胞产生的MPs会激活内皮细胞。从老龄小鼠浓缩红细胞（pRBCs）中分离出MPs，并用于处理培养的内皮细胞汇合层。在处理0.5、6、12和24小时后，评估白细胞粘附分子、内皮细胞-白细胞粘附分子-1（ELAM-1）和细胞间粘附分子-1（ICAM-1）的内皮表达以及炎性介质白细胞介素-6（IL-6）。给健康的C57BL/6小鼠输注MPs悬浮液，并分析肺切片中的粘附分子和隔离的间质白细胞。MPs刺激6小时后，培养的内皮细胞上ELAM-1和ICAM-1水平升高（相对荧光强度[RFI]分别为6.91对4.07，P<0.01，以及5.85对3.55 RFI，P=0.01）。与对照相比，MPs刺激12小时后细胞培养上清液中的IL-6增加（1.24对0.73 ng/mL，P=0.03）。体内实验表明，注射MPs在1小时时增加了ELAM-1和ICAM-1的表达（RFI分别为18.56对7.08，P<0.01，以及23.66对6.87 RFI，P<0.01），并在处理4小时时导致肺间质白细胞密度增加（69.25对29.25个细胞/高倍视野，P<0.01）。这一系列实验支持了我们的假设，即红细胞衍生的MPs能够激活肺内皮细胞，导致输注储存的pRBCs后白细胞在肺部滞留。
