Rheological Properties Of Erythrocytes Research Articles

Nitric oxide availability in cerebral microangiopathy

To develop a test of individual nitric oxide (NO) availability based on changes in erythrocyte rheological properties after incubation with a NO donor and to evaluate the role of these disorders in brain damage and development of cognitive impairment (CI) in cerebral small vessel disease (cSVD). In 73 cSVD patients (48 (65.8%) women, mean age 60.1±6.5), the rheological properties of erythrocytes before and after incubation with 10 μmol/L L-arginine-NO donor were evaluated using a laser-optical rotating cell analyzer, and the blood-brain barrier (BBB) permeability by MRI-T1 dynamic contrast. Among the studied parameters of erythrocyte rheological properties, the best characteristic by ROC analysis was the rate of erythrocyte disaggregation (y-dis) after incubation with L-arginine (area under the curve 0.733 (0.609-0.856), sensitivity 67%, specificity 79%). Patients with a y-dis threshold >113 sec-1 had more severe CI, arterial hypertension, white matter lesions, and increased BBB permeability in gray matter and normal-appearing white matter. The prolonged rate of erythrocyte disaggregation in cSVD patients after incubation with L-arginine indicates the risk for disease progression due to decreased NO bioavailability/disruption of the functional L-arginine-eNOS-NO system. This test can be used to assess individual NO bioavailability and potentially identify indications for modifying therapy with NO donors such as L-arginine. Clinical trials are needed to standardize and evaluate the efficacy of NO donor therapy in patients with cSVD and CI.

Physiological Dynamics of the Rheological Properties of Erythrocytes in Young Men Involved In Swimming

The parameters of erythrocytes largely determine the processes of blood movement through small vessels and metabolism in tissues. The study included 37 young men who during the past life showed low muscle activity and, at their own request, started regular swimming lessons 3 times a week. The control group consisted of 42 young men who, before being included in the study, went in for swimming for at least 5 years at least 3 times a week. Traditional hematological, biochemical and statistical research methods were used. Weakly physically trained young men before the start of swimming had an increased amount of altered forms of erythrocytes in the blood, which negatively affected their microcirculation. After six months of swimming in the blood of young men, the level of arachidonic acid derivatives normalized, the content of cholesterol molecules and acyl hydroperoxides in erythrocytes decreased, and phospholipids increased in their membranes. In the blood of swimmers, the number of discoid erythrocytes increased and the number of erythrocytes with an altered shape decreased. The control group, which had a long experience in swimming, was characterized by a high preservation of the shape of erythrocytes and an optimum of biochemical parameters taken into account. By the end of the observation, the novice swimmers showed the output of erythrocyte and biochemical parameters to the level of the control group.

Supervised Cycling Training Improves Erythrocyte Rheology in Individuals With Peripheral Arterial Disease.

Peripheral arterial disease (PAD) results in insufficient flow to lower extremities. Aerobic exercise provides health benefits for individuals with PAD, but basic science behind it is still debated. Twenty-one PAD patients aged about 70 years with female/male as 7/14 were recruited. Among them, 11 were randomized to have supervised cycling training (SCT) and 10 to receive general healthcare (GHC) as controls. SCT participants completed 36 sessions of SCT at the first ventilation threshold within 12 weeks and the controls received GHC for 12 weeks. Ankle-brachial index (ABI), 6-min walk test (6MWT), peak oxygen consumption (O2peak), minute ventilation (E), minute carbon dioxide production (CO2), erythrocyte rheology, including the maximal elongation index (EImax) and shear stress at 50% of maximal elongation (SS1/2), and the Short Form-36 (SF-36) questionnaire for quality of life (QoL) were assessed before and 12 weeks after initial visit. SCT significantly decreased the SS1/2 as well as SS1/2 to EImax ratio (SS1/2/EImax) and increased the erythrocyte osmolality in the hypertonic region as well as the area under EI-osmolality curve. The supervised exercise-induced improvement of erythrocyte deformability could contribute to the increased peripheral tissue O2 delivery and was possibly related with increased O2peak. The physiological benefit was associated with significantly increased ABI, 6-min walking distance, cardiorespiratory fitness, and SF-36 score. However, no significant changes in aerobic capacity and erythrocyte rheological properties were observed after 12-week of GHC. In conclusion, SCT improves aerobic capacity by enhancing erythrocyte membrane deformability and consequently promotes QoL in PAD patients.

Formalised assessment of systemic thrombogenicity in patients with Polycythemia vera suffered an ischemic stroke

Introduction. Thrombosis diagnosis and prevention in patients with Polycythemia vera (PV) suffered an ischemic stroke (IS) are still open. The aim was to find the reasons for systemic thrombogenicity and to compare the applicability of the main scales assessing thrombosis risk in patients with PV suffered IS.Materials and methods. We followed up 127 people (42-75 y.o.), of which 68 were patients with PV suffered IS (group I) and 59 non-PV-patients with ischemic stroke (group II). Clinical study included common blood analysis, rheological properties of erythrocytes, coagulation and endothelial parameters, cytokines, inflammation markers, angiogenesis markers, and testing for the V617F mutation in the JAK2 gene. The follow up included common and neurological examinations as well, and the assesment of thrombosis risk factors with both Caprini scale and CHA2DS2-VASc scale. All patients were examined twice as in the acute period of IS as well as in 16-18 months.Results. Between the groups no significant differences were found for the NIHSS average score and for Bartel index as well.The Caprini score belonged to the “very high risk” (score > 6) in both groups in the acute period of IS. At the same time, the score “8-10 points” prevailed in group II (68%) whereas the score “11-12 points” prevailed in group I.In the acute time of IS the CHA2DS2-VASc score revealed 12% of patients from both groups who had a score of “3-4 points” (moderate risk of thrombosis).In group I thrombotic complications rate correlated significantly with the JAK2V617F gene allelicloading (r = 0.236; p < 0.05), and the development of recurrence cerebrovascular disorders correlated significantly with Caprini score (r = 0.241; p < 0.05), but not with CHA2DS2-VASc score.Aiming to predict thrombotic complications in PV-patients the threshold (cut off) points were established for those markers as factor VIII, factor VII, red blood cell deformability, thrombin activated fibrinolysis inhibitor (TAFI), red blood cell count, white blood cell count, t-PA, VEGF-A, p-thrombomodulin, and ADAMTS-13.This pattern of parameters showed the odds ratio of thrombotic complications 10.3 (95% CI 7.6-13.8) in PV-patients in thelong-term period.At the end of the follow up the Caprini score showed a trend towards a decreasing in total while the CHA2DS2-VASc score remained virtually unchanged.Conclusion. We assume the accurate assessment of thrombotic risk in patients with Polycythemia vera suffered an ischemic stroke requires a proposed pattern of parameters including the test for JAK2V617F allelicloading and the calculation of Caprini score but not CHA2DS2-VASc score. Final results may provoke to change standard antithrombotic therapy in those patients towards its intensification due to pathogenetic featues of cancer-associated thrombosis.

Rheological Properties of the Erythrocytes in Weakened Static Magnetic Field of the Earth In vitro Study

Background: The magnetobiological effect of the weakened magnetic field of the Earth is of interest due to the consequences of the long stay of astronauts in space. Objective: The rheological properties of erythrocytes in a weakened magnetic field of the Earth are investigated. Methods: Osmotic gradient ektacytometry, aggregometry.
 Results: A study of the rheological properties of erythrocytes of blood rats in vitro, exposed at a temperature of 0°C in a natural and weakened magnetic field of the Earth, was carried out. It is established that a weakened magnetic field leads to a decrease in the rate of hemolysis, the average body volume, transformation, and decrease in the specific surface of the erythrocyte, potentiates the weakening of the deformation and aggregation properties.
 Conclusions: The results of the work should be taken into account not only to predict the rheological behavior of the blood system when the natural magnetic field is weakened but also to optimize the conditions for the long-term storage of donor blood.

Prevention of Cerebrovascular Disease in Patients with Myeloproliferatie Disorders

Introduction. Hemorheological abnormalities in patients with Ph-negative myeloproliferative disorders (MPD) may lead to the development and/or progression of cerebrovascular pathology. Adequate preventive therapy in such cases lowers the risk of cerebral thrombotic complications. Objective. Evaluation of the effect of dipyridamole and acetylsalicylic acid (ASA) on platelet and erythrocyte aggregation, as well as on morphofunctional properties of erythrocytes in patients with cerebrovascular disease (CVD) due to MPD. Materials and methods. The study comprised 40 patients with various forms of CVD and Рh-negative MPD: 20 patients received dipyridamole, and 20 received ASA for prevention of cerebral thrombotic complications. Mean patient’s age was 44.6 years [35; 58.5]. A thorough clinical and neurological examination was performed, as well as neuroimaging studies, coagulation tests, analysis of platelet aggregation and rheological properties of erythrocytes. Results. Within the observation period (median—6.3 months) no acute cerebrovascular events in both groups were registered. Platelet aggregation (induced by ADP or adrenaline) was similar in both groups. Dipyridamole and ASA were also similar in their effect on functional properties of erythrocytes. Conclusion. Our findings suggest that the therapeutic effect of dipyridamole concerning CVD is similar to that of ASA. Dipyridamole can be recommended for use in patients with Рh-negative MPD if other antiplatelet agents are contraindicated.

An explanation of the reversal of erythrocyte echinocytosis by incubation and storage by serum albumin

It is proposed that the specific reversal by serum albumin of the erythrocyte echinocytosis in an inorganic phosphate buffer saline or in a saline, either after 24 h in blood or after a storage of 6-7 weeks in SGAM or PAGGSM media, is due to a cell dehydration by a decrease of the total NaCl and KCl concentrations favoring the stomatocytogenic slow outward transport of inorganic phosphate with a hydrogen ion by band 3 anion exchanger, which was previously proposed to control the erythrocyte shape. This proposal would indicate that the opposition of the erythrocyte echinocytosis by serum albumin is not limited to binding to echinocytogenic amphiphiles, supported by the ability of the band 3-based mechanism of control of the erythrocyte shape to explain a variety of observations on the erythrocyte shape. It would also imply that this mechanism is a determinant of the erythrocyte rheological properties since influenced by cell shape and volume. It is shown that the above process of stomatocytosis can explain stomatocytoses by different agents as well as a knizocytosis induced in vitro and occurring in acquired and inherited disorders and other situations. Lastly, it can also explain the opposition of hemolysis by mannitol in SGAM and PAGGSM media.

Effects of Eccentric and Concentric Cycling Exercise Regimens on Hemodynamic and Hemorheologic Properties in Sedentary Males

Erythrocyte rheological properties significantly contribute to the dynamic regulation of vascular resistance to flow shear force, whereas impaired rheological functions of erythrocytes lead to circulatory disorders and exercise intolerance. This study investigated whether eccentric (ECE) and concentric (CCE) cycling exercise regimens influence hemorheological/hemodynamic responses to hypoxic stress in sedentary males. Twenty‐two healthy sedentary men were randomized to either ECE (n=11) or CCE (n=11) group. These subjects progressively performed ECE or CCE at 45% to 70% VO2max on a bicycle ergometer for 40 min/day, 5 days/week for 6 weeks. Erythrocyte rheological and central/peripheral hemodynamic characteristics at rest and after hypoxia exercise test (HE, 100W under 12% O2 for 40 min) were determined by laser diffraction ektacytometer and bioreactance‐based device/near infrared spectrometer, respectively. The result demonstrated that HE reduced erythrocyte deformability and increased erythrocyte aggregability under shear flow whereas CCE rather than ECE attenuated the extents of erythrocyte rheological impairment caused by HE. Although cardiac hemodynamic responses to exercise in the ECE group were smaller than those in the CCE group, the percentages of blood distributed to frontal cerebral lobe and vastus lateralis muscle in ECE group were larger than those in CCE group. Hence, we conclude that CCE effectively increases the resistance to hemorheological impairment evoked by HE, whereas ECE prominently enhances cerebral/muscular hemodynamic adaptions to exercise in sedentary males.

The effect of centrifugation at various g force levels on rheological properties of rat, dog, pig and human red blood cells.

Laboratory investigations often require centrifugation of blood samples for various erythrocyte tests. Although there is a lack of data about the effect of centrifugation at various g force levels on erythrocyte rheological properties. We aimed to investigate the effect of a 10-minute centrifugation at 500, 1000 or 1500 g at 15°C of rat, dog, pig and human venous (K3-EDTA, 1.5 mg/ml) blood samples. Hematological parameters, erythrocyte deformability, cell membrane stability, osmotic gradient ektacytometry (osmoscan) and erythrocyte aggregation were determined. Hematological and erythrocyte deformability parameters showed interspecies differences, centrifugation caused no significant alterations. Cell membrane stability for human erythrocytes centrifuged at higher g level showed less decrease in deformability. Osmoscan O min parameter showed slight elevation in dog centrifuged aliquots. Erythrocyte aggregation parameters changed unexpectedly. Rat and dog erythrocyte aggregation indices significantly dropped in centrifuged aliquots. Pig erythrocyte aggregation indices increased significantly after centrifugation. Human erythrocyte aggregation was the most stable one among the investigated species. The used centrifugation protocols caused the largest alterations in erythrocyte aggregation in a controversial way among the investigated species. On the other hand, erythrocyte deformability parameters were stable, cell membrane stability and osmoscan data show minor shifts.

Rheological Properties of Erythrocytes and Lipid Profiles of Blood Plasma

The study was carried out to evaluate the influence of lipid blood plasma in patients with stable angina on some rheological properties of the erythrocytes. It was found a clear increase of erythrocyte's aggregation propert ies from increase the atherogenic lipids in the blood plasma regardless from the content of high density lipoproteins. Erythrocyte deformability of red blood cells were not associate d with the plasma lipid profile.

Hemostasis in Erysipelas-The Reason for Considering Antithrombotic Therapy

The indices of external (prothrombin time, INR) and internal (activated partial prothrombin time (aTpp) coagulation pathways, the degree of disfibrinogenemia (thrombin time, functional fibrinogen activity and D-dimer level), the amount and functional activity of the platelets (aggregation with ADP) and the erythrocytes (aggregation with lanthanoid and protamine sulfate) were studied in 60 patients with erysipelas. Also, we have studied endothelial dysfunction manifested in the decrease of athrombogenicity of vascular wall endothelium (antithrombin III and protein C) and in the increase of adhesive properties of the endothelium (von Willebrand factor). The comparison groups comprised normal volunteers (n=32) and patients with focus of inflammation localized on the face (n=24), and the legs (n=36) at various stages of the disease (day 1–3; 4-6; 7-10; and 11-15 from the onset of the disease), undergoing in hospital treatment in Moscow 2nd Clinical Hospital for the Infectious Diseases. The thesis, according to which the rate of hemorrhagic complications in leg erysipelas is by 3,9 times higher than in facial erysipelas, was confirmed by laboratory findings. In particular, a significant decrease of protein C was noted in patients with leg erysipelas and concomitant chronic venous insufficiency. We have found increased D-dimer and decreased α2-macroglobulin levels, suggesting potent activation of proteolytic enzymes (plasmin, matrix metalloproteinases, neutrophil elastase), which can be one of the causes of bullae, erosion and ulceration formation in the erysipelas focus on the lower limb. The signs of intravascular (latent) hemolysis - the decrease of haptoglobin concentration and the increase of indirect bilirubin and LDH blood level; the changes of rheological properties of erythrocytes – the increase of deformability (aggregation with lanthanum chloride) and the decrease of elasticity (aggregation with protamine sulfate) – have been identified as one of the main factors for DIC-like syndrome in erysipelas.

Stretching training affects erythrocyte rheological properties and anaerobic performance in healthy young males

Stretching training affects erythrocyte rheological properties and anaerobic performance in healthy young males

The effect of lead-induced oxidative stress on blood viscosity and rheological properties of erythrocytes in lead exposed humans

Lead-induced oxidative stress has been identified as the essential factor in lead poisoning pathogenesis. Therefore, the present study examined the association between occupational lead exposure and blood rheological parameters with respect to malondialdehyde (a lipid peroxidation product), lipofuscin, and glutathione concentrations in erythrocytes. The examined group included 283 healthy male employees of lead-zinc works. In brief, 129 workers were classified as the low-exposure group, while the high-exposure group was composed of 154 workers. The mean blood levels of lead and zinc-protoporphyrin and the mean urine concentrations of delta-aminolevulinic acid were used as exposure markers. The control group consisted of 73 healthy male administrative workers. Whole blood viscosity was elevated in both exposure subgroups compared with the control group. Erythrocyte aggregability increased significantly; although the increase was greater in the low exposure group. Erythrocyte deformability decreased in both subgroups. The levels of malondialdehyde and lipofuscin were significantly elevated, whereas the glutathione content decreased. In conclusion, occupational exposure to lead may induce oxidative stress in erythrocytes. This stress elevates whole blood viscosity and disturbs erythrocyte aggregability and deformability. There is a dose-effect relationship between lead levels and blood rheological parameters.

Altitude training induced alterations in erythrocyte rheological properties: A controlled comparison study in rats

Altitude training is frequently used by athletes to improve sea-level performance. However, the objective benefits of altitude training are controversial. This study aimed to investigate the possible alterations in hemorheological parameters in response to altitude training. Sprague Dawley rats, were divided into 6 groups: live low-train low (LLTL), live high-train high (LHTH), live high-train low (LHTL) and their controls live high and low (LHALC), live high (LHC), live low (LLC). LHC and LHTH groups were exposed to hypoxia (15% O2, altitudes of 3000 m), 4 weeks. LHALC and LHTL were exposed to 12 hours hypoxia/normoxia per day, 4 weeks. Hypoxia was maintained by a hypoxic tent. The training protocol corresponded to 60-70% of maximal exercise capacity. Rats of training groups ran on treadmill for 20-30 min/day, 4 days/week, 4 weeks. Erythrocyte deformability of LHC group was increased compared to LHALC and LLC. Deformability of LHTH group was higher than LHALC and LLTL groups. No statistically significant alteration in erythrocyte aggregation parameters was observed. There were no significant relationships between RBC deformability and exercise performance. The results of this study show that, living (LHC) and training at altitude (LHTH) seems more advantageous in hemorheological point of view.

Rheological properties of erythrocytes and blood coagulation characteristics of healthy milk-fed piglets

Investigations are carried out on 32 healthy Large White piglets in the milk-fed stage at ages of 6, 10, 15, and 20 days. By the end of this stage, a tendency toward an increase in the number of discocytes in the piglets’ blood to 86.5% and a decrease in the level of reversibly modified erythrocytes to 8.8% and irreversibly modified to 4.7% is noted. An insignificant increase in the level of total involvement of erythrocytes into aggregates (by 2.5%) and number of aggregates themselves (by 4.1%) with a 3.5% reduction of freely moving erythrocytes is revealed. Piglets aged 6–20 days are characterized by a tendency toward intensification of the activity of individual clotting factors (I, II, VII, VIII, IX, and XII) with unchanged activity of factors V, X, and XI. Gradual acceleration of activated partial thromboplastin time from 38.9 s on day 6 to 37.7 s on day 20 is noted. In this case, prothrombin time decreases slightly by day 20, to 16.7 s. Thrombin time, reflecting the intensity of transition of fibrinogen to fibrin, also accelerates, reaching 16.8 s.

Effects of Aspirin on RheologicalProperties of Erythrocytes In Vitro

Aspirin is of proven value as an antithrombotic drug. In unstable angina it reduces the risk of death and myocardial infarction by half. Most studies on the mechanism of action of aspirin have concentrated on the effect of aspirin on platelets.In the present study we have tried to prove that there is another biophysical mechanism of aspirin, and that is through the effect of aspirin on erythrocytes. In this study ten blood samples were incubated with aspirin at different concentrations. The fractal dimension of erythrocytes subjected to shear rates from 5 s-1 to 30 s-1, in a cone and plate device designed and constructed in our lab, was calculated by processing the images of the erythrocyte. At each shear rate, the fractal dimensions of the erythrocytes were found to be strongly correlated with aspirin concentration. It is suggested that further studies using different biophysical methods must be carried out to detect the other mechanisms underlying the effect of aspirin on different blood cells.

In vivo influence of extract from Aronia melanocarpa on the erythrocyte membranes in patients with hypercholesterolemia

SummaryBackgroundHypercholesterolemia increases cholesterol concentration in erythrocyte membranes, which results in decrease of membrane fluidity and decreases the deformability of red blood cells. The fruits of Arona melanocarpa contains many of polyphenols and other compounds that have beneficial health effects.Material/MethodsThe aim of the study was to estimate the influence of 2-month supplementation of extract from Aronia melanocarpa (100 mg Aronox, three times per day) on cholesterol concentration, lipid peroxidation, membrane fluidity, level of thiol groups and activity of ATPase in erythrocytes from patients with hypercholesterolemia. The study involved 25 patients with hypercholesterolemia without pharmacological treatment and 20 healthy individuals as a control group. Blood samples were collected before, and after 1 and 2 months of Aronia administration.ResultsThe 2-month Aronia supplementation resulted in a decrease of cholesterol concentration (by 22%) and a decrease of lipid peroxidation (by 40%), and an increase of membrane fluidity. No statistically significant increase of the concentration of thiol groups and of ATPase activity were observed.ConclusionsOur study shows that supplementation of extract from Aronia melanocarpa has a beneficial effect on rheological properties of erythrocytes.

The effects of exercise in water at 4°C and 25°C on the rheological properties of blood and the composition of fatty acids in the erythrocyte membranes of laboratory rats

The aim of this study was to assess the influence of a single session of maximal exercise performed in water (4°C or 25°C) on blood rheological properties and the composition of fatty acids in the erythrocyte membranes of laboratory rats. This study will permit better understanding of the reactions occurring in the organism during rapid cooling in cold water, especially in regards to the hemorheological and biochemical parameters of blood. When compared to the control group, exercise performed in water at 4°C led to an increase in the elongation index (EI, from 0.30 Pa to 4.24 Pa) with no concurrent changes in erythrocyte aggregation, blood plasma viscosity, and fatty acid composition (saturated, unsaturated, saturated/unsaturated, monounsaturated, polyunsaturated polyunsaturated-n3, polyunsaturated-n6 fatty acids) of the erythrocyte membrane. In rats swimming in water at 25°C, we observed an increase in EI at shear stress from 0.30 Pa to 2.19 Pa, along with a decrease in the half-time of total aggregation when compared to the control group. These changes in erythrocyte rheological properties can be treated as a protective reaction to thermal stress resulting in their improved deformability.

Effects of Cold Water Swimming on Blood Rheological Properties and Composition of Fatty Acids in Erythrocyte Membranes of Untrained Older Rats

This is the first report on the effects of a single bout of swimming to exhaustion in cold water on rat erythrocyte deformability, aggregation and fatty acid composition in erythrocyte membranes. The results indicate that there was a significant decrease in body temperature of experimental rats swimming in water at 4 degrees C and 25 degrees C when compared to the control. Erythrocyte aggregation indices did not change after swimming in water at 4 degrees C whereas erythrocyte deformability increased at shear stress 1,13 [Pa] and 15,96 [Pa]. Physical effort performed in water at 4 degrees C when compared to the control group resulted in an increase in monounsaturated and polyunsaturated n-3 fatty acid content in erythrocyte membranes that influenced the increase in their fluidity and permeability even though that of polyunsaturated n-6 fatty acids decreased. Physical effort performed in 25 degrees C water resulted in an increase in saturated fatty acid content and a decrease in all polyunsaturated fatty acids and polyunsaturated n-6 fatty acids when compared to the control group. Swimming of untrained old rats in cold water affected rheological properties oferythrocytes in a negligible way while changes in the fatty acid composition of erythrocyte membranes were more pronounced.

Influence of Glucose Concentration on the Membrane Stability of Human Erythrocytes

The action of glucose as an osmolyte in relation to blood cells is not well-characterized in the literature. This study aimed to study the influence of glucose concentration on the stability of red blood cells. The stability of erythrocytes was evaluated by the half-transition point obtained from the curves of lysis induced by glucose in the absence of salt or by increase in medium hypotonicity in the absence and the presence of different concentrations of glucose. In the presence of 0.9 g/dl NaCl, there was no hemolysis with increasing concentration of glucose from 0 to 10 g/dl. In the absence of NaCl, the dependence of hemolysis with the 0-10 g/dl glucose was described by a decreasing sigmoid, with fully lysed and fully protected cells being encountered in the presence of 0-2 and 4-10 g/dl glucose, respectively. The possible origin of such stabilization effect is discussed with base of what is known about osmostabilization of biological complexes and about the influence of glucose on the rheological properties of erythrocytes.