The method for determining the degree of venous pathology depending on the index of erythrocytes deformability

Aim. To study the ability of erythrocytes to deformability in patients with chronic diseases of the veins of the lower extremities. Materials and methods. From March to July 2019, we conducted a study of the deformability of erythrocytes in 271 railway workers using the method of laser diffractometry. The study of blood samples was carried out at the Department of Human and Animal Anatomy and Physiology of the Institute of Biology. At the same time, there were 182 people with varicose veins of the lower extremities, which was confirmed by the data of ultrasound angioscanning of the veins. Results. Studying the deformability of red blood cells of venous blood in patients with chronic venous disease of the lower extremities, we have identified certain patterns. With the increase in the clinical stage (form) of the disease of varicose veins of the lower extremities, the deformability of erythrocytes decreases, the deterioration of blood parameters is determined, which is confirmed by the data of a small coagulogram and a general blood test. The deformability index in the range from 0.12 to 0.42 indicates a violation of venous outflow in the subcutaneous venous system of the lower extremities, the deformability index from 0.42 and above indicates the presence of a thrombotic process in the deep veins of the lower extremities. Conclusion. With an increase in the erythrocyte deformability index, venous insufficiency increases, and venous outflow worsens. The higher the severity of the disease (clinical form C4-6), the lower the deformability of erythrocytes. In patients with VBLK, as the disease progresses, there is a decrease in the deformability of erythrocytes (i. e., in patients with the clinical form according to CEAP C2-3, the deformability is higher than in C3-4; in patients with C3-4, it is higher than in С4-5 … etc.).

HEMORHEOLOGICAL PROPERTIES OF THE 5-HT2A-ANTAGONIST OF THE 2-METHOXYPHENYL-IMIDAZOBENZIMIDAZOLE DERIVATIVE OF THE RU-31 COMPOUND AND CYPROHEPTADINE, IN COMPARISON WITH PENTHOXYPHYLLINE

Migraine and its comorbid conditions are pathogenetically associated with many factors, including hemorheological disorders. A class of drugs with a 5-HT2A antagonistic mechanism of action, is promising for the prevention and treatment of migraine attacks and concomitant pathologies.The aim of the research is to study and compare a hemorheological activity of anti-migraine drugs, antagonists of 5-HT2A receptors of cyproheptadine, and a new drug that completed preclinical studies of the 1-(2-diethylaminoethyl)-2-(4-methoxyphenyl)-imidazo[1,2-a]benzimidazole derivative of the RU- 31 compound.Materials and methods. The study of the hemorheological activity of the RU-31 compound and cyproheptadine, was carried out using an experimental model of rabbit blood hyperthermia in vitro. Pentoxifylline was used as a reference drug. In the course of the work, the parameters of blood viscosity, aggregation and deformability of erythrocytes were recorded.Results. It has been established that in the concentration of 1 μM, the RU-31 compounds reduce blood viscosity by 17% at high shear rates, which is comparable with pentoxifylline in the concentration of 100 μM on the activity level. In the concentration of 1 μM, cyproheptadine also causes a general tendency to reduce blood viscosity at high shear rates, being inferior in activity to the RU-31 compound and pentoxifylline. In the concentration of 1 μM, the RU-31 compound has a pronounced effect on the aggregation ability of erythrocytes in autologous plasma, reducing the aggregation rate by 70%, while the level of activity is not inferior to the drug compared to pentoxifylline in the concentration of 100 μM, and surpasses the drug cyproheptadine. For the RU-31 compound and cyproheptadine, no significant effect on the deformability of erythrocytes has been shown.Conclusion. The capacity of cyproheptadine and the RU-31 compound to influence the rheological properties of blood by reducing blood viscosity and aggregation of erythrocytes has been revealed.

Deformability of Erythrocytes is maintained after Autologous Cell Salvage in Orthopedic Surgery

Background and Objective: Prerequisite for oxygen transport to the tissue is the ability of erythrocytes to change from a discoid into an elongated form in order to pass microvessels. Cell salvage is highly recommended to decrease blood loss and to avoid allogeneic transfusions in perioperative bleeding. The purpose of our study was to assess deformability of erythrocytes at re-transfusion. Materials and Methods: After ethics committee approval and informed consent, blood was withdrawn from the autotransfusion system (Xtra, Sorin, Germany) of 24 patients undergoing joint arthroplasty 6 hours after cell salvage initiation. Deformability curves, elongation indices (EI) obtained at increasing shear stress (SS) were assessed by using Laser Optical Rotational Red Cell Analysis (LORRCA). Results: Erythrocytes showed the typical sigmoid EI/SS curve with a mean maximum elongation index (EImax) of 0.593 ± 0.034 and mean half-maximal deformation (SS ½) of 1.186 ± 0.387 Pa. Irregular curve shapes and high variability in EI occurred at shear stress < 3 Pa. Recalculation of outcome parameters resulted in higher values (EImax 0.610 ± 0.035; SS ½ 1.562 ± 0.346 Pa). Conclusion: Erythrocytes after autologous cell salvage are not stiff but elongate in response to shear stress. Erythrocytes showed the typical EI/SS-curve of human red cells, which indicates that the cells are able to uptake the hydrodynamic forces that act on them during the measurement. Further research is needed to investigate the effect of cell salvage processing on erythrocytes from patients with pre-existing hematological disorders.

Plasmodium falciparum ligand binding to erythrocytes induce alterations in deformability essential for invasion

The most lethal form of malaria in humans is caused by Plasmodium falciparum. These parasites invade erythrocytes, a complex process involving multiple ligand-receptor interactions. The parasite makes initial contact with the erythrocyte followed by dramatic deformations linked to the function of the Erythrocyte binding antigen family and P. falciparum reticulocyte binding-like families. We show EBA-175 mediates substantial changes in the deformability of erythrocytes by binding to glycophorin A and activating a phosphorylation cascade that includes erythrocyte cytoskeletal proteins resulting in changes in the viscoelastic properties of the host cell. TRPM7 kinase inhibitors FTY720 and waixenicin A block the changes in the deformability of erythrocytes and inhibit merozoite invasion by directly inhibiting the phosphorylation cascade. Therefore, binding of P. falciparum parasites to the erythrocyte directly activate a signaling pathway through a phosphorylation cascade and this alters the viscoelastic properties of the host membrane conditioning it for successful invasion.

Erythrocyte Rigidity Affects Blood Clot Contraction and Formation of Polyhedrocytes

Blood clot contraction or retraction has been implicated to play a significant role in hemostasis, reduction of thrombus volume, and wound healing. Clot contraction is driven by forces that are generated by platelets and transmitted by fibrin and results in volume shrinkage followed by the compaction of erythrocytes into the core of the blood clot, resulting in their mechanical deformation towards a polyhedral shape, giving rise to the term polyhedrocytes. Despite the fact that erythrocytes are a major component of blood clots, relatively little is known about the influence of the mechanical properties or deformability of erythrocytes on the process of clot contraction. Increased hematocrit reduces extent of clot contraction due to mechanical resilience of erythrocytes and it is likely that in addition to a volume fraction the stiffness of erythrocytes can also affect the extent and rate of clot contraction. Here we tested this assumption by using artificially or naturally stiffened erythrocytes that have pathophysiological implications. The reduced deformability of erythrocytes is associated with a number of pathological conditions, such as hypertension, diabetes mellitus, atherosclerosis and smoking, but perhaps one of the most well-known diseases associated with increased erythrocyte rigidity is sickle cell disease (SCD). Another example of naturally stiff erythrocyte membrane is that of llama or camel that have red blood cells with increased osmotic resistance. To assess the extent of clot contraction, we used an optical tracking methodology that allows for the quantitative tracking for clot size. To assess the influence of erythrocyte rigidity on clot contraction we also used scanning electron microscopy to evaluate deformations of the erythrocytes, including the presence of polyhedrocytes. Centrifugation of citrated blood can be used to mimic the contractile forces generated by platelets and has been shown to cause polyhedrocyte formation. Increasing the erythrocyte rigidity through their treatment with a low concentration of glutaraldehyde resulted in a decrease in polyhedrocyte formation and the requirement of larger centrifugal forces to observe erythrocyte deformation, suggesting that the mechanical properties of erythrocytes could influence the process of clot contraction. As residual glutaraldehyde may have unwanted effects on platelets, clot contraction experiments were completed using naturally stiffer erythrocytes from SCD patients and llama ovalocytes, which are stiffer than human erythrocytes due to the increased amount of the membrane cytoskeletal protein spectrin. SCD patients were only included in this study if they had Sickle Trait, SCD Hb SS, SCD Hb SC and have not received recent transfusions. The blood samples of SCD patients were examined and on average had a 53% decrease (p<0.0001) in the extent of clot contraction compared to healthy subjects. Likewise, addition of llama ovalocytes to human platelet rich plasma resulted in a 28% decrease in extent of clot contraction compared to human erythrocytes and larger centrifugal forces were needed to see red cell deformation. SCD patients contracted 2.4X slower (p<0.001) during linear contraction (Phase 2) and 2.7X slower (p<0.05) during mechanical stabilization (Phase 3) when compared to healthy subjects. Clot contraction was impaired also by erythrocytes treated with antibodies that bind to the Wright b epitope on the erythrocytes and exert a rigidifying effect on the cells. The binding of the antibody to erythrocytes was determined by flow cytometry and the KD was ~50 nM. Increased red blood cell rigidity following exposure to antibodies was confirmed through mechanical and osmotic resistance and compared to unaltered erythrocytes. Collectively, these results demonstrate that erythrocyte mechanical properties can influence the process of clot contraction so that stiffer cells reduce the rate and extent of clot contraction. A better understanding of the role of erythrocyte deformability in the process of clot contraction has the potential to inform the development of more targeted treatments for limiting bleeding and thrombosis in patients who are prone to having altered erythrocyte content and mechanical properties of these highly abundant cells embedded into blood clots and thrombi. Disclosures Weisel: Bayer: Research Funding.

THE MICROCIRCULATION PARAMETERS IN PATIENTS WITH ODONTOGENIC INFLAMMATORY DISEASES OF MAXILLOFACIAL AREA

The aim of the study was to determine changes of certain microcirculation parameters in patients with odontogenic inflammatory diseases of maxillofacial area. Material and methods. The study included the results of a comprehensive survey of 31 patients with infectious and inflammatory diseases of maxillofacial area of odontogenic etiology and 30 healthy donors. We studied the deformability of erythrocytes and aggregation of the suspension of leukocytes and platelets. Results. The parameters of the level and speed of the aggregation of the suspension of leukocytes and platelets in the development of infectious inflammatory diseases of maxillofacial area of odontogenic pathology increase in regard to those in healthy persons. At the same time, the similar comparison of the erythrocyte deformability in patients reliably decrease. Conclusion. There is a decrease in the erythrocyte deformability and increase in the rate and degree of aggregation of the suspension of leukocytes and platelets with the development of odontogenic infectious and inflammatory diseases in maxillofacial area. During the treatment of the patients the microcirculation abnormalities are preserved. The index of erythrocytes deformability in the blood plasma rises towards the end of the treatment relative to the values determined for just hospitalized patients.