Erythrocyte Rouleaux Formation Research Articles

Clinical improvement of Long-COVID is associated with reduction in autoantibodies, lipids, and inflammation following therapeutic apheresis

In the aftermath of the COVID-19 pandemic, we are witnessing an unprecedented wave of post-infectious complications. Most prominently, millions of patients with Long-Covid complain about chronic fatigue and severe post-exertional malaise. Therapeutic apheresis has been suggested as an efficient treatment option for alleviating and mitigating symptoms in this desperate group of patients. However, little is known about the mechanisms and biomarkers correlating with treatment outcomes. Here, we have analyzed in different cohorts of Long-Covid patients specific biomarkers before and after therapeutic apheresis. In patients that reported a significant improvement following two cycles of therapeutic apheresis, there was a significant reduction in neurotransmitter autoantibodies, lipids, and inflammatory markers. Furthermore, we observed a 70% reduction in fibrinogen, and following apheresis, erythrocyte rouleaux formation and fibrin fibers largely disappeared as demonstrated by dark field microscopy. This is the first study demonstrating a pattern of specific biomarkers with clinical symptoms in this patient group. It may therefore form the basis for a more objective monitoring and a clinical score for the treatment of Long-Covid and other postinfectious syndromes.

Kinetic study of acid depolymerization of chitosan and effects of low molecular weight chitosan on erythrocyte rouleaux formation

In this study, the depolymerization of chitosan was carried out in an acetic acid aqueous solution and was followed by viscometry for molecular weight determination. It was found that the depolymerization rate increased with elevated temperatures and with high acid concentrations. Based on FTIR analysis, the chitosan was depolymerized randomly along the backbone; no other structural change was observed during the acid depolymerization process. Revealed in the TGA study, the degradation temperature and char yield of LMWCs (low molecular weight chitosan) were molecular weight dependent. The blood compatibility of LMWCs was also investigated: rouleaux formation was observed when erythrocyte contacted with LMWCs, which showed that LMWCs are able to interfere with the negatively charged cell membrane through its polycationic properties. Furthermore, as regards a kinetics investigation, the values of M n (number-average molecular weight) were obtained from an experimentally determined relationship. The kinetics study showed that the complex salt, formed by amine on chitosan and acetic acid, acted as catalyst. Finally, the activation energy for the hydrolysis of the glycosidic linkage on chitosan was calculated to be 40 kJ/mol; the mechanism of acid depolymerization is proposed. In summary, LMWCs could be easily and numerously generated with acid depolymerization for further biological applications.

Effect of electroconvulsive stimulation on morphological and physiological aspects of post-cardiac arrest cerebral microcirculation

We investigated the effect of electroconvulsive stimulation (ECS) on cerebral circulation in vivo using the method for measuring microcirculation in real time with the photosensitizer dye Photosense and the fiber optic spectrofluorometer LESA-01-BIOSPEC. We have found that electroconvulsive stimulation significantly improved cerebral microcirculation (fourfold higher comparing to the control cerebral perfusion) after 30 min of room-temperature cardiac arrest. Morphologic study of the brain tissue showed the absence of rouleaux formation of erythrocytes ("sludged blood") in the cerebral cortex microcirculation after the application of electrical stimulus. Electroconvulsive stimulation may be useful for improving cerebral microcirculation (blood flow) in cases of long-term brain hypoxia/anoxia after prolonged cardiac arrest.

Assessment of Ischemia and Reperfusion Injury

Direct videomicroscopy of the rat cremaster muscle microcirculation supplemented by animal models of replantation, vascular crushing, and muscle function after injury and recovery were used to investigate the occurrence of reperfusion failure. It is evident that failure of blood reflow may be induced by multiple factors that can be grouped into categories of ischemia, intimal damage, and systemic or local responses, which are referred to as the no reflow triad. The components comprising the 3 sides of the no reflow triad can interact with one another in an intricate manner, and any single factor or combination of factors is capable of triggering the events leading to reperfusion failure. The pronounced regional nature of reperfusion injury and the direct relationship between the severity of the observed vascular alterations and increasing duration of ischemia have been documented. The dynamic changes and histopathology of the microcirculation included constriction of the arteries, swelling of endothelial and leukocytes, and erythrocyte rouleaux formation during ischemia. As ischemia duration was lengthened, the degree of these changes increased correspondingly. The changes on reperfusion were disruption of blood flow patterns, vortex formation, regional stasis, adhesion and migration of leukocytes, focal hemorrhage, edema, vasospasm, and platelet aggregation. The deleterious effects of systemic acidosis, interstitial hemorrhage, denervation, and prolonged venous occlusion were subsequently documented. The application of information gained from this series of laboratory experiments has resulted in continued improvement in the success rate in clinical microvascular surgery.

Effect of immunoglobulin preparations on the aggregation of human erythrocytes

The aggregation of human erythrocytes induced by four kinds of immunoglobulin preparations was examined by a low shear rheoscope. After removing anti-A+ and anti-B+ activities contaminated in all preparations by incubating with erythrocytes of different blood groups, the facilitating effect on the rouleau formation of erythrocytes was compared: (i) The effect of polyethyleneglycol-treated preparation was the same in A+-, B+-, AB+- and O+-erythrocytes. (ii) Sulfonation did not affect the velocity of rouleau formation. (iii) Some of pepsin-treated preparations showed the strongest facilitation for A+-, B+- and AB+-erythrocytes, but the facilitation was much weaker for O+-erythrocytes. The others showed the weak facilitation for all types of erythrocytes (especially O+-erythrocytes). (iv) Plasmin treatment markedly decreased the velocity of rouleau formation of AB+- and O+-erythrocytes, but was not of A+- and B+-erythrocytes.

Rouleau formation of erythrocytes: A dynamical model

A model is presented for the nonBrownian motion of living erythrocytes suspended in their own plasma as observed by Rowlands et al. On the basis of this model, the formation of rouleaux (contractile fibrils among interacting erythrocytes) can be described in terms of an organization of the molecules (mainly fibrinogen) present in blood plasma; this organization is sustained by the nonlinear propagation of electric vibrations generated by red blood cells (coherent electric vibrations of the Frohlich type). A number of peculiar experimental features otherwise unexplained can also be taken into account in the framework of the model.

Ig A · K type myeloma with severe postextraction bleeding

A case of multiple myeloma detected by the first symptom of severe postextraction bleeding was presented. Although laboratory data showed severe anemia, rouleaux formation of erythrocytes, abnormal hemostatic parameters, elevated erythrocyte sedimentation rate and hyper-globulinemia, no involvement of bones such as the jaws, skull, ribs or sternum was demonstrated roentgenologically. Final diagnosis obtained by Immunoelectrophoresis was Ig A · K type myeloma. During a therapeutic period with melphalan and predonine, bleeding from the extracted wound was repeated. 2 months after the onset of the first symptoms, the patient died of systemic bleeding. Autopsy findings revealed many hemorrhagic sites in the lungs, stomach, kidney and bladder and the existence of plasma cell-like tumor cells in the bone marrow of lumber vertebra and sternum.

Kinetics of rouleaux formation using TV image analyzer. I. Human erythrocytes.

An apparatus for determining the velocity of erythrocyte rouleaux formation was constructed, combining an inverted microscope, a transparent cone-plate viscometer, a TV image analyzer, and a computer. At lower shear rates, the overall process is the sedimentation and the rouleaux formation followed by the development of three-dimensional aggregates. The individual erythrocyte could be observed and the process was expressed by the time courses of the changes in the count and area of particles; taking the computed increment in the area/count, the rate of rouleaux formation could be estimated. The effects of shear rates, hematocrits, plasma proteins, and pH were quantified. The rate of rouleaux formation in autologous plasma increased by (1) lowering the shear rates (1.9 less than or equal to gamma less than or equal to 15 s-1),2) increasing the hematocrit (up to 0.6%), 3) adding human fibrinogen (up to 600 mg/dl) or gamma-globulin, and 4) increasing pH. The transformation to echinocytes or to stomatocytes decreased the rate of rouleaux formation. The pH effect was explained by the increase in mean corpuscular volume at lower pH rather than by the changes in the electrostatic repulsion or in the protein binding.