Unsolved Favorable Effect of Statin on Blood Viscosity

No abstract available.

Usefulness of Frozen-thawed-deglycerolized Red Blood Cells as Quality Control Materials for Red Blood Cell Deformability Test / 대한진단검사의학회지

BACKGROUND: The red blood cell (RBC) deformability test is a useful method for measuring the ability of RBCs to adapt their shape to the flow conditions. Using this test, several investigators have shown the relationship between RBC deformability and numerous clinical conditions. For the quality control (QC) of RBC deformability test, we evaluated whether frozen-thawed-deglycerolized RBCs can be used as QC materials. METHODS: Packed RBCs were frozen with 40% (wt/vol) glycerol and stored at -80degrees C for 3 months. For 10 different frozen RBC panels, RBCs were thawed, deglycerolized and stored at 4degrees C for 4 weeks. Using microfluidic ektacytometer, we measured RBC deformability of the thawed RBCs. The stability of thawed RBCs was tested once a day for 28 days of storage time and was analyzed by simple regression analysis. The precision of the test using thawed RBCs was analyzed for 7 days of storage time by calculation of CV values of intra-assay (10 measurements/assay) and between-day measurements. RESULTS: Frozen-thawed-deglycerolized RBCs were stable for 1 week. Within-run and between-day precisions of the RBC deformability test during 7 days of storage of thawed RBCs were 1.4-2.9%, and 1.9-2.8%, respectively. CONCLUSIONS: Frozen-thawed-deglycerolized RBCs used in RBC deformability test showed satisfactory within-run and between-run precisions and stability for one week after thawing, and may be used as QC materials for this test.

Assessment of Hemorheological Deformability of Human Red Cells Exposed to tert-Butyl Hydroperoxide, Verapamil and Ascorbate by Ektacytometer / 대한진단검사의학회지

BACKGROUND: Normal erythrocyte is deformable and this facilitates blood flow in the capillaries. Oxidative stress reduces the deformability of erythrocytes, and influences on blood flow in microcirculation. The objective of this study was to investigate the deformability of erythrocytes exposed to oxidative stress, the protective effects of verapamil and ascorbic acid against oxidative damages in erythrocytes, and the value of the microfluidic ektacytometer, RheoScan-D (RheoMeditech, Korea) in clinical application. METHODS: Effects of oxidative stress on erythrocytes were investigated using tert-butyl hydroperoxide (tBHP). Before exposure to tBHP, the erythrocytes were pretreated with verapamil and ascorbic acid to examine their protective effect against oxidative damages. The deformability of erythrocytes was measured by the microfluidic ektacytometer, RheoScan-D. RESULTS: When treated with tBHP, the deformability of erythrocytes was decreased (P<0.01) and methemoglobin (metHb) formation and mean corpuscular volume (MCV) of erythrocytes were increased (P<0.01, P<0.05) compared to those of the untreated control cells. Compared to the tBHP treated cells, pretreatment with verapamil increased the deformability of erythrocytes (P<0.01) and decreased metHb formation (P<0.01) and MCV (P<0.05). Likewise, pretreatment with ascorbic acid increased the deformability of erythrocytes (P<0.01) and decreased metHb formation (P<0.01). CONCLUSIONS: Oxidative stress reduces the deformability of erythrocytes and the deformability could be one of markers for oxidative damage. Verapamil and ascorbic acid have protective role against tBHP induced oxidative stress. The ektacytometer, RheoScan-D used in this study is convenient for clinical measurement and could be used in various fields of clinical medicine.

Changes in the Physical Properties of Irradiated Red Blood Cells / 대한수혈학회지

BACKGROUND: Irradiation of cellular blood products is the current method used for the prevention of transfusion-associated graft-versus-host disease. However, irradiation has been shown to cause biochemical changes in stored red blood cells (RBCs) and to generate reactive oxygen species (ROS). Irradiation-induced biochemical changes and oxidation damage of the RBCs is closely related to the deformability of these cells. Furthermore, deformation of the RBCs may lead to alterations in the post-transfusion viability of stored RBCs. In this study, we evaluated the physical properties of irradiated RBCs. METHODS: Citrate phosphate dextrose adenine-1 preserved RBC concentrates were irradiated with a minimum dose of 25 Gy and stored at 4oC for 28 days. The deformation of the RBCs was measured by a microfluidic ektacytometer (RheoScan-D). To examine the effect of oxidative stress, the RBC concentrates were exposed to oxidative stress using FeSO4 and ascorbic acid. RESULTS: The deformability threshold of the irradiated RBCs was significantly lower than that of the control RBCs on day 21 of storage and later (P<0.05). The deformability threshold of the RBCs exposed to oxidative stress was lower than that of control RBCs, and the difference was significant on day 21 of storage and later (P<0.05). For up to 21 days of storage, the deformability of control and irradiated RBCs were maintained; however, they were significantly decreased at 28 days of storage compared with 1 day of storage (P<0.05). CONCLUSION: Irradiation reduced the threshold of RBC deformability during storage. In accordance with the effect of irradiation, oxidative stress affected the RBC deformability. Therefore, a ROS scavenger may play a protective role against deformation of irradiated RBC concentrates. Further evaluation will be required for confirmation and clarification of these findings.