Enhanced Erythrocyte Aggregation Research Articles

Strain- and sex-specific differences in intestinal microhemodynamics and gut microbiota composition.

Intestinal microcirculation is a critical interface for nutrient exchange and energy transfer, and is essential for maintaining physiological integrity. Our study aimed to elucidate the relationships among intestinal microhemodynamics, genetic background, sex, and microbial composition. To dissect the microhemodynamic landscape of the BALB/c, C57BL/6J, and KM mouse strains, laser Doppler flowmetry paired with wavelet transform analysis was utilized to determine the amplitude of characteristic oscillatory patterns. Microbial consortia were profiled using 16S rRNA gene sequencing. To augment our investigation, a broad-spectrum antibiotic regimen was administered to these strains to evaluate the impact of gut microbiota depletion on intestinal microhemodynamics. Immunohistochemical analyses were used to quantify platelet endothelial cell adhesion molecule-1 (PECAM-1), estrogen receptor α (ESR1), and estrogen receptor β (ESR2) expression. Our findings revealed strain-dependent and sex-related disparities in microhemodynamic profiles and characteristic oscillatory behaviors. Significant differences in the gut microbiota contingent upon sex and genetic lineage were observed, with correlational analyses indicating an influence of the microbiota on microhemodynamic parameters. Following antibiotic treatment, distinct changes in blood perfusion levels and velocities were observed, including a reduction in female C57BL/6J mice and a general decrease in perfusion velocity. Enhanced erythrocyte aggregation and modulated endothelial function post-antibiotic treatment indicated that a systemic response to microbiota depletion impacted cardiac amplitude. Immunohistochemical data revealed strain-specific and sex-specific PECAM-1 and ESR1 expression patterns that aligned with observed intestinal microhemodynamic changes. This study highlights the influence of both genetic and sex-specific factors on intestinal microhemodynamics and the gut microbiota in mice. These findings also emphasize a substantial correlation between intestinal microhemodynamics and the compositional dynamics of the gut bacterial community.

A topical platelet-independent multilevel clotting initiator for intraoperative hemostasis

Quick and stable clotting is essential in topically controlling intraoperative hemorrhage for patients with chemotherapy-induced thrombocytopenia. Here, we proposed and validated a kind of vesicle originated from gene-engineering cell membrane to manage uncontrolled bleeding with double clotting-triggering strategy. The vesicle constitutively exhibited truncated tissue factor (tTF) protein and phosphatidylserine (PS), thus function as a fibrin growth stimulus and erythrocyte attractant initiator in vitro and in vivo. Erythrocytes assembled in blood clot protected formed fibrin from fibrinolysis while the grown fibrin network enhanced erythrocyte aggregation in situ. Notably, these double clotting-triggering processes worked synergistically to constitute a positive feedback effect to quickly and potently form fibrinolysis-resisted erythrocyte-modified fibrin structures and achieve more stable clotting than the commonly used thrombin and gelatin coagulant. Furthermore, FDA-approved biocompatible Pluronic F127 hydrogel was rationally introduced to assist vesicles depositing onto the wound, thereby maximizing the hemostatic activity and minimizing the postoperative adhesion in a hemorrhage model with cyclophosphamide-induced myelosuppression. This multi-level coagulant method reported here sheds new light on controlling bleeding when patients with myelosuppression undergo surgery.

Hemorheological and metabolic consequences of renal ischemia-reperfusion and their modulation by N,N-dimethyl-tryptamine on a rat model.

Micro-rheological relations of renal ischemia-reperfusion (I/R) have not been completely elucidated yet. Concerning anti-inflammatory agents, it is supposed that sigma-1 receptor agonist N,N-dimethyl-tryptamin (DMT) can be useful to reduce I/R injury. To investigate the micro-rheological and metabolic parameters, and the effects of DMT in renal I/R in rats. In anesthetized rats from median laparotomy both kidneys were exposed. In Control group (n = 6) no other intervention happened. In I/R group (n = 10) the right renal vessels were ligated and after 60 minutes the organ was removed. The left renal vessels were clamped for 60 minutes followed by 120-minute reperfusion. In I/R+DMT group (n = 10) DMT was administered 15 minutes before the ischemia. Blood samples were taken before/after ischemia and during the reperfusion for testing hematological, metabolic parameters, erythrocyte deformability and aggregation. Lactate concentration significantly increased and accompanied with decreased blood pH. Enhanced erythrocyte aggregation and impaired deformability were observed from the 30th minute of reperfusion. In I/R+DMT group we found diminished changes compared to the I/R group (lactate, pH, electrolytes, red blood cell deformability and aggregation). Metabolic and micro-rheological parameters impair during renal I/R. DMT could reduce but not completely prevent the changes in this rat model.

Age- and gender-related hemorheological alterations in intestinal ischemia-reperfusion in the rat

BackgroundIntestinal ischemia-reperfusion (I/R) is a life-threatening clinical disorder. During I/R, the microrheological parameters of blood (red blood cell deformability and aggregation) worsen, which may contribute to microcirculatory deterioration. Age and gender also have a great influence on hemorheological parameters. We aimed to investigate the gender and age-related microrheological alterations during intestinal I/R. Materials and methodsAfter the cannulation of the left femoral artery, median laparotomy was performed in Crl:WI rats under general anesthesia. In the young control animals there were no other interventions (female n = 7; male n = 7). In the young (female n = 7; male n = 7) and older I/R groups (female n = 6; male n = 6), the superior mesenteric artery was clipped for 30 min, and a 120-min reperfusion period was observed afterward. Blood samples were taken before and at the 30-min ischemia, in the 30th, 60th, and 120th min of the reperfusion. Hematological parameters, erythrocyte deformability, and aggregation were determined. ResultsHematocrit increased significantly in the younger female I/R group. Red blood cell count was higher in male and older animals. In case of white blood cell count, male animals had higher values compared with females. Platelet count elevated in the younger male and older female I/R animals. Red blood cell deformability worsened, mainly in the male and older I/R groups. Enhanced erythrocyte aggregation was seen in all groups, being more expressed in the female I/R groups. ConclusionsMicrorheological parameters show gender and age-related differences during intestinal I/R. These observations have importance in the planning and evaluation of experimental data.

The Impact of Biophysical Properties of Erythrocytes on their Aggregation

Erythrocytes aggregation takes places under low shear conditions or at stasis. All suggested mechanisms of erythrocytes aggregation indicated the importance role of fibrinogen and other blood proteins in enhanced erythrocyte aggregation. Recently a special attention is given to the cellular factors that may effect on erythrocytes aggregation. The present study inferred the effect of the cellular properties of erythrocytes on their aggregation. In the present study, aggregation index was calculated by a simple microscopic method. Correlations between erythrocytes aggregation index and mean cell volume, osmotic fragility, electrophoretic mobility, and magnetophoretic mobility were studied. The findings of this study indicated that the aggregation index is significatly correlated to mean cell volume, magnetophoretic mobility, osmotic fragility and electrophoretic mobility. Thus, It is concluded that cellular factors should be taken into consideration when studying the mechanism of erythrocytes aggregation.

Aggregation and deformability of erythrocytes in primary open-angle glaucoma (POAG); the assessment of arterial hypertension

Primary open-angle glaucoma (POAG) is one of the most common types of glaucoma. Glaucoma is a progressive neuropathy of the optic nerve with characteristic visual area disorders. The aim of this study was to assess the correlations between rheological parameters of blood and other parameters such as: intraocular pressure, visual acuity, angular breadth of the aqueous fluid eluvium, visual area and arterial hypertension. The examined group was comprised of 54 patients with POAG. Out of this group two subgroups was separated: I subgroup of 24 patients without hypertensive and II subgroup of 30 patients with chronic hypertensive disease. The control group was comprised of 40 healthy subjects. Erythrocyte aggregation and deformability analysis were determined using LORCA. From the results we concluded that rheological disorders such as enhanced erythrocyte aggregation or significantly decreased erythrocyte deformability occur in patients with POAG. Additionally, it revealed a significant relation between the duration of hypertension and an increased erythrocyte aggregation index (r = +0.27 p < 0.005) along with decreased deformability (r = -0.37 p < 0.001), where the decrease in deformability correlated with the severity of hypertonic retinal angiopathy (r = -0.30 p < 0.05). All these disorders may result in decreased blood flow to the optic nerve, which contributes towards the development of neuropathy.

Red blood cell phosphatidylserine exposure is responsible for increased erythrocyte adhesion to endothelium in central retinal vein occlusion

Retinal vein occlusion (RVO) is a common cause of permanent loss of vision. The pathophysiology is uncertain, although enhanced erythrocyte aggregation and blood hyperviscosity have been observed. Increased red blood cell (RBC) adhesion has been associated with vascular complications in several diseases, such as sickle cell anemia, diabetes mellitus or polycythemia vera. To measure RBC adhesion to endothelial cells in RVO and to explore the molecular basis of the adhesion process. We assessed RBC adhesion to endothelial cells and adhesion molecule expression among 32 patients with RVO. Patients with disease known to alter RBC adhesion were excluded (n = 8), and further investigation was conducted in 20 patients with central retinal vein occlusion (CRVO) and four patients with retinal artery occlusion (RAO), compared with 25 normal subjects. Under static conditions, adhesion of CRVO RBC was increased (135 ± 7 × 10(2) mm(-2)) compared with RAO RBC (63 ± 5 × 10(2) mm(-2)) (P < 0.01) and normal control RBC (37 ± 3 × 10(2) mm(-2)) (P < 0.001). Under flow conditions, CRVO RBC adhered in greater numbers than normal RBC (P < 0.001). Phosphatidylserine (PS) expression on CRVO RBC was 2.4-fold higher than controls and correlated with RBC adhesion (P = 0.001). In static conditions, specific antibodies against PS receptor and annexin V inhibited RBC adhesion. In flow conditions, the inhibitory effect was in the same range with antibodies but was 2-fold higher with annexin V. Increased CRVO RBC adhesion is mediated by PS RBC and endothelial PS receptor. This phenomenon may be one of the factors responsible for CRVO.

Effect of Various Infusion Solutions on Microrheology

Objective: to evaluate the in vitro and in vivo effects of various infusion solutions on red blood cell rheology in the early posttraumatic period. Material and methods. The in vitro study assessed crystalloids, albumin, dextrans, modified gelatin, and different generations of hydroxyethyl starches (HES). The preparations were added to blood in a 1:10 dilution; before and after their addition, the values of erythrocyte aggregation and erythrocyte deformability were estimated. The in vivo study covered 59 patients with severe concomitant injury, who were divided into 3 groups: 1) those who received crystalloids only; 2) those who had crystalloids + 6% HES 130/0.42; 3) those who had crystalloids + gelofusine. The same parameters of red blood cell rheology were estimated as in the in vitro study. Results. Albumin, repolyglycan, and HES 130/0.42 were found to have the most pronounced disaggregatory effect in vitro. At the same time, polyglycan, gelofusine, and HES 450/0.7 in particular, enhanced erythrocyte aggregation. In vitro, albumin, HES 130/0.42, and HES 200/0.5 exerted the most beneficial effect on erythrocyte deformability whereas dextrans made the latter worse and HES 450/0.7 and gelofusine failed to have a considerable effect on it. The early posttraumatic period was marked by progressive erythrocyte hyperaggregation and phasic deformability changes. Significant microrheological disorders persisted in the patients on infusion therapy with crystalloid solutions only. Addition of HES 130/0.42 to infusion therapy improved the deformability of erythrocytes and lowered their aggregation. The use of gelofusine as a component of infusion therapy caused a moderate increase in erythrocyte aggregation. Key words: infusion therapy, erythrocyte deformability, erythrocyte aggregation.

Enhanced erythrocyte aggregation in type 2 diabetes with late complications.

We investigated whether erythrocyte aggregation (EA) is enhanced in type 2 diabetic patients who have developed microvascular or macrovascular complications. EA rates at high and low shear rates were analysed in 141 patients with type 2 diabetes who were further divided into 4 subgroups according to the status of diabetic complications and degree of metabolic control. Groups 1 (n = 43) and 2 (n = 23) consisted of well-controlled patients without and with clinically evident late complications, while groups 3 (n = 33) and 4 (n = 42) represented poorly controlled patients without and with these complications, respectively. 124 healthy subjects served as the control group. Mean EA rate was comparable between control subjects and group 1 both at high (2.05 +/- 0.03 vs. 2.14 +/- 0.07, respectively) and low (6.96 +/- 0.02 vs. 7.04 +/- 0.06, respectively) shear rates. Mean EA rate was also comparable between groups 2 and 4 at high (2.76 +/- 0.09 vs. 2.94 +/- 0.07, respectively) and low (8.18 +/- 0.13 vs. 8.41 +/- 0.1, respectively) shear rates. However, EA at both shear rates in groups 2 and 4 were significantly higher than control subjects, group 1 (p < 0.0001) and group 3 (high shear rate EA: 2.76 +/- 0.09 and low shear rate EA: 7.48 +/- 0.07 (p < 0.01). In group 3, EA rates were significantly higher than control subjects and group 1 (p < 0.05) at both shear rates. No significant correlation was found between EA at high and low shear rates and fibrinogen levels in diabetic subgroups and control subjects. The data suggest that patients with type 2 diabetes who had developed clinically evident late complications have enhanced EA regardless of the degree of metabolic control. Whether enhanced EA is a primary phenomenon contributing to the development of these complications or it occurs secondary to their development remains to be clarified.

Increased strength of erythrocyte aggregates in blood of patients with inflammatory bowel disease

Increased strength of red blood cell (RBC) aggregates are present during the acute inflammatory response and contribute to erythrocyte aggregation and may lead to microvascular dysfunction. Inflammatory bowel diseases (IBDs) are characterized by damage to the bowel wall. This damage may be at least partially attributed to microvascular ischemia caused by enhanced erythrocyte aggregation. The aim of this study was to evaluate the strength of RBC aggregates in the blood of patients with IBD. The strengths of RBC aggregates were characterized by integrative RBC aggregation parameters, determined by measuring of RBC aggregation as a function of shear stress. The results are represented as the area under the curve (AUC) of aggregate size plotted against shear stress. For each patient, dynamic aggregation and disaggregation of RBC were recorded and analyzed according to the RBC aggregate size distribution at the different shear stresses. Aggregation indices were correlated with disease activity and inflammatory biomarkers. We examined 53 IBD patients and 63 controls. IBD patients had significantly elevated concentrations of inflammation-sensitive proteins and aggregation parameters. The strength of large aggregates, represented by AUC for large fraction aggregates, among patients (15.2 +/- 18.6) was double that of controls (7 +/- 10.9) (P = 0.006). The strength of large aggregates correlated with disease activity (r = 0.340; P < 0.001) with concentration of fibrinogen (r = 0.575; P < 0.001) and with concentration of high sensitivity C-reactive protein (r = 0.386; P < 0.001). The strength of RBC aggregates is increased in patients with IBD and correlates with the intensity of the acute phase response. This could contribute to bowel damage in these diseases.

Enhanced Erythrocyte Aggregation in Clinically Diagnosed Pelvic Inflammatory Disease

Enhanced erythrocyte aggregation, revealed using a simple bedside test, has been found recently in several inflammatory conditions. The diagnosis of pelvic inflammatory disease (PID) is at times difficult because of the vague symptoms and signs, but is crucial because even mild PID can have future reproductive consequences. Our objective was to determine the degree of erythrocyte aggregation in PID. The demonstration of an increase in aggregation could be of additive value in cases in which the diagnosis is difficult. A prospective case-control study was conducted. Fifteen consecutive women diagnosed clinically as having PID based on Centers for Disease Control and Prevention criteria, and 15 matched controls were enrolled. Blood samples were drawn for hematologic indices, C-reactive protein, fibrinogen levels, and red cell aggregation. We studied the degree of red cell aggregation using a simple slide test and image analysis. The variable measured was the erythrocyte percent (EP), equivalent to the slide area covered by erythrocytes. Erythrocyte percent was 59.6 +/- 4.2 and 80.0 +/- 3.6 for the study group and controls, respectively (P <0.001). A significant difference was noted also for the other hematologic and biochemical markers of inflammation between patients and the controls. We conclude that the degree of erythrocyte aggregation is increased in PID. Its simplicity, rapidity, and low cost should be further evaluated as a diagnostic tool in the context of this frequent disease.

Association of components of the metabolic syndrome with the appearance of aggregated red blood cells in the peripheral blood. An unfavorable hemorheological finding.

Components of the metabolic syndrome are associated with low-grade inflammation. This can be accompanied by the synthesis of sticky proteins and erythrocyte aggregation. The degree of erythrocyte aggregation was evaluated by a simple slide test and image analysis along with other markers of the acute-phase response, including the white blood cell count (WBCC), erythrocyte sedimentation rate (ESR), fibrinogen and high sensitivity C-reactive protein (hs-CRP) concentrations. Patients were categorized in four groups according to the absence or presence of 1, 2 and 3 or more components of the metabolic syndrome. We examined a total of 1447 individuals (576 women and 871 men) who gave their informed consent for participation. A significant cardiovascular risk factors, age and hemoglobin adjusted correlation was noted between the degree of erythrocyte aggregation and the number of components of the metabolic syndrome (r = 0.17, p < 0.0005). This correlation was better than that observed for clottable fibrinogen (r = 0.13 p < 0.0005), for ESR (r = 0.11 p < 0.0005) or WBCC (r = 0.13 p < 0.0005). A somewhat better correlation was noted for hs-CRP (r = 0.26 p < 0.0005). The multiplicity of components of the metabolic syndrome is associated with enhanced erythrocyte aggregation, probably related to the presence of multiple adhesive macromolecules in the peripheral blood. The enhanced aggregation might contribute to capillary slow flow, tissue deoxygenation as well as vasomotor tone changes in the presence of multiple components of this syndrome.

Elaborated - ‘Georgian index’ of erythrocyte aggregability characterizing the microrheological disorders associated with brain infarct

Since the role of microvascular rheological disorders has been so far insufficiently analysed in development of stroke, we examined in course of acute stage of ischemic brain infarcts the most essential· feature of disorders - erythrocyte aggregability with 'Georgian technique' assuring direct and quantitative data. In addition, ultrasonic Doppler scanning of cerebral arteries, computerized tomography, magnetic resonance imaging, and serial cerebral angiography were repeatedly applied. Index of erythrocyte aggregability was found more than twice higher in acute stage of ischemic brain infarcts than in healthy control group. In a significant number of cases infarcts were produced by microcirculatory stases, related to enhanced erythrocyte aggregation. Aggregability index was found to be more sensitive as compared to blood plasma fibrinogen content and blood hematocrit for prediction of dynamics and outcome of acute phase of disease. In addition, aggregability designated extent of the accompanied brain edema. We arrived at conclusion that erythrocyte aggregability is a notable feature characterizing the microvascular hemorheological disorders. It represents an essential risk-factor furthering both development of microcirculatory stases and ischemic brain infarcts. Necessarily, it is to be tested with most perfect techniques providing reliable diagnosis and prognosis of the disease.

赤血球集合と赤血球変形能に関する研究 ヘマトクリット，細胞内Ｃａ｀＋＋´濃度，デキストラン濃度との関連

Enhanced erythrocyte aggregation and decreased eryhrocyte deformability are thrombogenetic factors, especially in microcirculation where shear rate is low. The aim of this report is to investigate the relationships between erythrocyte aggregation, erythrocyte deformability, hematocrit, plasma viscosity and intracellular free calcium of erythrocyte. Venous blood samples were taken from resting subjects into Na-citrate. Erythrocytes were suspended in calcium free HEPES buffer. Erythrocyte aggregation was measured at high and low shear rate by using the technique which is based on the increase of light transmission through whole blood that occurs when individual cells aggregate into rouleaux or rouleaux-rouleaux complexes; gaps in whole blood between the cell aggregates produce the increased light transmission. The levels of [Ca2+] i of erythrocytes were measured by using fluorescent Ca2+ indicator, fura-2 acetoxymethyl ester. Plasma viscosity was measured via capillary viscometry and erythrocyte deformability was measured by the method of Reid et al. and whole blood hematocrit by microhematocrit method. Both erythrocyte aggregation and erythrocyte deformability were decreased with increasing plasma viscosity and [Ca2+] i of erythrocyte. Erythrocyte aggregation was enhanced with increasing hematocrit. Thus these behaviors of erythrocytes in microcirculation contribute to formation of microthrombi especially at low shear rates.

Physical factors important in the development of atherosclerosis in diabetes.

Circulation of the blood is a process controlled by physical laws. The same physical laws also determine the sites of atherosclerotic plaques. Our understanding of their role in atherogenesis is aided by a review of (1) the difference between a solid and fluid, (2) strain and shear or strain rate and shear rate as describers of motion, (3) the distinction between force as pressure and as shear stress, (4) the effects of viscosity and inertia on fluid motion, and (5) the nonlinear responses of blood and blood vessels. Moving blood affects the vessel wall principally through shear stress, the force due to its viscosity applied parallel to the surface of the vessel. Excessive shear stress occurs near the orifices of branches of the aorta, the arterial areas where atherosclerotic plaques develop. It is produced by a change in blood flow pattern at these sites. Arterial stiffening in diabetes reduces the ability of the branches of the aorta to dilate during systole, a motion that helps to control high wall shear stress. At wall shear stress levels under 400 dynes/cm2, a value only modestly higher than that normally achieved near the orifices of the major arterial branches, the endothelial lining of the arterial wall becomes disrupted, allowing entry of plasma proteins and lipids. Blood viscosity elevation in diabetes, linked to enhanced erythrocyte aggregation and reduced erythrocyte deformability, adds to the shear stress at the vessel wall, favoring increased lipid entry. Exposed to a high lipid influx secondary to excessive wall shear stress, the arterial wall must rely on physical as well as chemical means to remove the lipids. Subendothelial motion generated by diastolic arterial contraction and systolic expansion appears to cause plasmalemmal vesicle formation and dissolution, an event probably important in the removal process. The combination of arterial stiffening and hemorheologic disturbance adds to the burden of increased plasma lipids to favor the development of atherosclerosis in diabetes.