ABSTRACT
The adherence of red blood cells (RBC) to endothelial cells (EC), shown to correlate with microvascular occlusion in sickle cell disease and malaria, is considered a major contributor to microcirculatory disorders. In the present study the adherence to EC was markedly enhanced with RBC from beta-thalassaemia major (TM) patients, and even more so with RBC from beta-thalassaemia intermedia (TI) patients (10-fold and 25-fold higher than normal, respectively). It is proposed that enhanced RBC/EC adherence may contribute to the microcirculatory disorders observed in thalassaemia, especially in TI patients who are particularly known to suffer from leg ulcers.
Subject(s)
Cell Adhesion/physiology , Erythrocytes/physiology , beta-Thalassemia/blood , Endothelium, Vascular/pathology , Endothelium, Vascular/physiology , HumansABSTRACT
BACKGROUND: Storage of blood units (for 35-42 days, depending on the preservative solution) has been reported to induce changes (e.g., reduction of sialic acid level) in red cells that are expected to alter their aggregability. STUDY DESIGN AND METHODS: The aggregability of stored red cells was monitored in their autologous plasma and compared to that obtained with washed cells in dextran-containing buffer throughout the storage period. Red cell aggregability was determined by using a computerized image analyzer of cell flow properties. RESULTS: Blood storage induced changes in red cells that are associated with continuous increase of their aggregability. At the same time, blood storage was associated with a reduction in the level of plasma fibrinogen, the major aggregating agent in plasma. Accordingly, the increased red cell aggregability was observed in red cells stored in dextran-containing buffer, but not in red cells stored in autologous plasma. CONCLUSION: Because blood transfusion is routinely given to patients with normal or high fibrinogen level, the transfusion of stored red cells has the potential to induce increased aggregation in vivo, depending on the storage period. This should be taken into account when blood transfusion is considered, particularly for patients with microcirculatory disorders.
Subject(s)
Blood Preservation , Erythrocyte Aggregation , Erythrocytes, Abnormal , Erythrocytes/ultrastructure , Buffers , Cell Separation , Dextrans/pharmacology , Erythrocyte Membrane/chemistry , Erythrocyte Membrane/physiology , Fibrinogen/analysis , Humans , Image Processing, Computer-Assisted , Microscopy, Electron, Scanning , N-Acetylneuraminic Acid/blood , Plasma , Stress, Mechanical , Time FactorsABSTRACT
Red blood cell (RBC) intercellular interactions, i.e., self-aggregation and adherence to endothelial cells (EC), play important roles in microcirculation. These RBC flow properties are determined by cell membrane components, which are prone to damaging reactive oxygen species (ROS) produced in oxidative stress (OS) states. Alterations in RBC aggregability and adherence have been linked to the pathophysiology in numerous diseases associated with OS. We investigated RBC intercellular interactions in four OS states--thalassemia, treatment of RBC with phenyl-hydrazine or H2O2, and photodynamic virus inactivation of blood units. All these OS states increased RBC adherence to EC, but only part of them elevated their aggregability, while others abolished it. It is proposed that (1) different OS states might induce disparate effects on RBC intercellular interactions; (2) RBC aggregability and adherence to EC, although both intercellular interactions, are controlled by different cell surface factors.
