Erythrocyte-Derived Microparticles Activate Pulmonary Endothelial Cells in a Murine Model of Transfusion

Abstract

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, ELAM-1 and ICAM-1, and inflammatory mediator, IL-6, were evaluated at 0.5, 6, 12, and 24 hours 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 hours 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 hours of MP stimulation compared to 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 hour (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 hours of treatment (69.25 vs 29.25 cells/HPF, 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.

Complement C5a Induces Pro-inflammatory Microvesicle Shedding in Severely Injured Patients

“…Severe injury causes changes of MV phenotypes including increased shedding of platelet-, erythrocyte-, endothelial-, and monocyte-derived MVs, which are able to promote coagulation ( 58 , 59 ) and inflammation in trauma ( 57 , 60 ). Moreover, erythrocyte-derived MV have been shown to activate pulmonary endothelial cells by increase of ELAM-1 and ICAM-1 expression as well as leukocyte-recruitment into the lung, which aggravated lung injury ( 61 ). Although elevated numbers of granulocyte-derived MVs after trauma, major burn, and sepsis have been reported ( 24 , 62 , 63 ), there is still little knowledge about their role in trauma and sepsis.…”

Tissue Factor-Negative Cell-Derived Microparticles Play a Distinctive Role in Hemostasis: A Viewpoint Review

“…Literature suggests that RMP may be equally effective for this purpose and less likely to cause complications often associated with platelet concentrates. 58,59 In summary, better understanding of this proposed "C" pathway of hemostasis could lead to new therapies to minimize transfusion requirements and blood loss in trauma and surgery patients.…”

The number of red blood cell-derived microparticles in predicting periprocedural adverse effects in acute STsegment elevation myocardial infarction patients

“…Indeed, pro-coagulant thrombotic activity of RBC-MPs and their ability inducing platelet activation and aggregation might explain the role of them in the pathogenesis of periprocedural microvascular obstruction and left ventricular remodeling [54,55]. Therefore, RBC-MPs are able to activate endothelium in visceral organs and thereby influence vasoconstriction and direct injury of them [56,57]. In this context, RBC-MPs measured in the peripheral blood may be sensitive markers of the thrombo-occlusive vascular process developing in the coronary arteries of STEMI-patients [58,59].…”