Clinical Hemorheology and Microcirculation - Volume 38, issue 3

Authors: Feher, Gergely | Koltai, Katalin | Kesmarky, Gabor | Toth, Kalman

Article Type: Research Article

Abstract: Background: Pathologic hemorheological parameters and increased platelet aggregation in association with other risk factors significantly increase the possibility of the development of ischemia. Acetylsalicylic acid (ASA) is an effective antithrombotic agent, which prevents a variety of cardiovascular diseases. Objectives: The aim of our present study was to compare the hemorheological parameters of patients with effective platelet inhibition by ASA to those with ineffective one. Methods: 2045 patients taking 100 mg ASA daily were involved in our study (1255 males, mean age: 63±11 yrs, 790 females, mean age: 63±12 yrs). To exclude the effect of risk profile, previous diseases and medication, …323 patients (197 males, mean age 60±13 yrs and 126 females, mean age 60±12 yrs) were selected from the examined group with matching parameters. Blood was taken after an overnight fast between 8:00 and 9:00 a.m. Platelet aggregation was measured in Carat TX-4 optical platelet aggregometer. Blood hematocrit was measured by Heraeus microhematocrit centrifuge and red blood cell aggregation was detected by Myrenne aggregometer. Plasma fibrinogen was measured by Clauss' method. Plasma and whole blood viscosities were measured in Hevimet 40 capillary viscosimeter. Results: Patients with effective ASA inhibition had significantly lower plasma fibrinogen level (p<0.05) and red blood cell aggregation values both in the heterogenous and the selected populations (p<0.01). The other hemorheological parameters were not statistically different in the two groups. Conclusion: The background of ineffective ASA medication has not yet been fully elucidated. Higher fibrinogen concentration increases red blood cell aggregation and can also result in increased platelet aggregation. Thus, increased plasma fibrinogen level may play an important role in the in vitro and in vivo platelet resistance to ASA. Show more

Keywords: Hemorheology, fibrinogen, ASA resistance, platelet

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 3, pp. 143-152, 2008

Authors: Shin, Sehyun | Ku, Yun-Hee | Suh, Jang-Soo | Singh, M.

Article Type: Research Article

Abstract: Glucose-rich plasma is commonly observed in diabetes mellitus and in-vitro incubation of erythrocytes in glucose-rich media may produce the non-enzymatic glycosylation of erythrocyte proteins. The present study investigates the effects of an increased concentration of glucose in a suspending medium on erythrocyte rheological parameters. Erythrocytes, which were obtained from ten healthy volunteers, were washed and incubated in vitro with glucose solutions at different concentrations and incubation times. The measured hemorheological parameters included deformability and the aggregation of erythrocytes. Hemoglobin concentration in the erythrocyte suspension in autologous plasma was also measured after incubation in order to assess the hemolysis of erythrocytes. …Significant hemorheological changes were observed with an increase of glucose concentration and incubating time. Both deformability and the aggregation of erythrocytes decreased in dose- and time-dependent manner. A reduction in hemoglobin concentration in the erythrocyte suspensions was also observed due to hemolysis of fragile erythrocytes during incubation. Modification in the hemorheological properties of cells, which may be associated with due to glucose-induced (auto)oxidation and glycation of erythrocyte proteins in hyperglycemia, can adversely affect the fluidity and oxygen-delivery function of the erythrocytes. Show more

Keywords: Erythrocytes, glucose, deformability, aggregation, glycation

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 3, pp. 153-161, 2008

Authors: Gründling, M. | Lehmann, Ch. | Saeger, D. | Bohnenstengel, S. | Pavlovic, D. | Bac, V. | Usichenko, T. | Meissner, K. | Wendt, M. | Hung, O. | Murphy, M. | Whynot, S. | Lindequist, U.

Article Type: Research Article

Abstract: KKP723 (KKP), a derivative of ampicillin, is a newly developed β-lactam antibiotic. Using an experimental endotoxemia model, the intestinal microcirculation in four groups of animals were evaluated using intravital microscopy (IVM). The groups included were a control group, an endotoxemic group (15 mg/kg i.v. LPS from E. coli), an ampicillin (50 mg/kg i.v.) treated endotoxemic group and an endotoxemic group treated with KKP (67.4 mg/kg i.v.). Ampicillin treatment resulted in a significant reduced number of firmly adhering leukocytes in intestinal submucosal venules. KKP treatment did not show this effect on leukocyte activation. We found no changes of the functional capillary …density (FCD) of the intestinal wall by treatment with ampicillin or its derivative KKP. The increased leukocyte adherence in the KKP treated LPS animals may be explained by a loss of a possible ampicillin-related anti-inflammatory effect by the biotransformation process. The endotoxemia IVM model is useful to detect effects of antibiotics in an impaired microcirculation. Show more

Keywords: Ampicillin, endotoxemia, microcirculation, leukocyte adhesion

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 3, pp. 163-170, 2008

Authors: Spengler, M.I. | Bertoluzzo, S.M. | Catalani, G. | Rasia, M.L.

Article Type: Research Article

Abstract: The aim of the present paper is to analyze whether membrane fluidity can be predicted from its lipid composition and to assay the possible relationship between such variable and the aggregating properties of erythrocytes from equine, bovine and human species due to the widely acknowledged differences in their tendency to form aggregates. The main difference between phospholipids from plasma membrane in these species lies in the concentration levels of sphyngomyelin (SM) and phosphatidilcoline (PC); more precisely, in the external hemilayer of the lipid bilayer. Membrane fluidity was estimated by the fluorescence polarization method, while erythrocyte aggregation was assessed …by an optical method. According to our results, bovine erythrocytes containing high SM and low PC levels, presented the highest anisotropy value as well as an imperceptible aggregation value. Equine erythrocytes, which contain a considerable PC percentage and scarce SM levels, showed the lowest anisotropy value and the highest values of the aggregation parameters. Human erythrocytes presented intermediate values for both properties. Our hypothesis claims that the phospholipid composition would constitute one of the factors determining erythrocyte membrane fluidity and also taking part in the different aggregation tendency shown by equine, bovine and human species. Show more

Keywords: Membrane erythrocyte fluidity, erythrocyte aggregation, phospholipids composition of erythrocyte membrane

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 3, pp. 171-176, 2008

Authors: Li, Min | Zhao, Ming-Qi | Kumar Durairajan, Siva Sundara | Xie, Li-Xia | Zhang, Hong-Xia | Kum, Wan-Fung | Goto, Shinya | Liao, Fu-Long

Article Type: Research Article

Abstract: Apoptosis induced by high shear stress has been reported for the dysfunction of various vascular endothelial cells. We investigated the protective effects of tetramethylpyrazine (TMP) and salvianolic acid B (SAB) from Chinese medicine on the shear-induced early and late stages of apoptosis in cultured rat cerebral microvascular endothelial cells (rCMECs) under pathological high shear stress. Near-confluent cultures of rCMECs were pretreated with TMP or SAB and their combinational dosages, and exposed to high shear stress generated by a rheometer. Apoptotic death rate of rCMECs was assessed by immunofluorescence microscopy of Annexin V-FITC and propidium iodide (PI). We found that early …and late stage apoptosis occurred at 3.0 Pa for a short duration of 450 sec but did not occur at 1.5 Pa. SAB inhibited the cells from apoptosis at concentrations from 10 μM to 20 μM in a dose-dependent manner, while effect of TMP at 0.37 mM and 0.73 mM did not significantly differ. Moreover, the combined use of TMP and SAB had synergistic anti-apoptotic effects (P<0.01). The results indicate that the anti-apoptotic effect of TMP and SAB on rheologically induced endothelial injury is likely involved in their efficacy. Show more

Keywords: Tetramethylpyrazine (TMP), salvianolic acid B (SAB), shear stress, apoptosis, endothelial cells

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 3, pp. 177-187, 2008

Authors: Amararene, Amar | Cloutier, Guy

Article Type: Research Article

Abstract: Parametric imaging of backscatter indices is an active field of research in ultrasound (US) tissue characterization. The US intensity reflection coefficient (IRC) is introduced to characterize porcine blood in a Couette shear flow system. US properties of red blood cells (RBCs) were investigated at shear rates of 5 s−1 and 500 s−1 for hematocrits ranging from 0 to 54%. The IRC was determined and compared to the integrated backscatter power (IBP) calculated between 8 MHz and 12 MHz. The frequency dependence of both parameters was also explored using their spectral slopes determined in the same frequency bandwidth. The …experimental results showed that the IRC is a mirror function of the IBP and their spectral slopes had similar behavior. At a shear rate of 500 s−1 , selected to disaggregate RBCs, the IRC exhibited a bi-modal variation with a minimum at 23% hematocrit. The minimum was less pronounced and moved down to 13–17% hematocrits in the case of a shear rate of 5 s−1 that promoted aggregation. The IBP presented a sharp peak at 25% hematocrit for the high shear-rate value, while a plateau appeared after 13% hematocrit in the case of the low shear rate. Furthermore, the transition from lower to higher shear rate was accompanied by a diminution in the level of both indices. In the frequency domain, the spectral slope of the backscatter power presented a Rayleigh scattering behavior (value around 4) for all hematocrits at a shear rate of 500 s−1 . It dropped to a value of 2 beyond 13% hematocrit when the shear rate was decreased to 5 s−1 . At a shear rate of 500 s−1 , the spectral slope of the IRC was constant and close to 3.8 below 28% hematocrit and decreased at higher hematocrits. At 5 s−1 , it was constant (between 3.7 and 3.9) for hematocrits lower than 17% and then decreased. This study showed the potential of the intensity reflection coefficient to investigate the RBC aggregation phenomenon. An advantage of IRC is its easy computation. Show more

Keywords: Ultrasound, intensity reflection coefficient, integrated backscatter power, spectral slope, red blood cells, aggregation

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 3, pp. 189-200, 2008

Authors: Futrakul, Narisa | Butthep, Punnee | Futrakul, Prasit

Article Type: Research Article

Abstract: Current treatments of chronic kidney disease (CKD) patients frequently result in progressive decline in renal perfusion, leading to the end-stage renal disease. Such renal failures may be a reflection of the progressive nature of renal microvascular disease. The aim of the present study is to elucidate the mechanism of microvascular homeostasis in CKD patients with moderately impaired renal function. We determined biomarkers relevant to vascular homeostasis, such as circulating endothelial cell (CEC), and biomarkers of vascular repair, such as vascular endothelial growth factor (VEGF), angiopoietin-1, tie-2, angiopoietin-2 and VEGF-R2. The present result revealed an enhanced vascular injury which was reflected …by increased number of circulating endothelial cells. In addition, a defective vascular repair was also reflected by deficiencies in angiogenic factors such as VEGF, and angiopoietin-1, whereas the anti-angiogenic factors such as angiopoietin-2 and VEGF-R2 were elevated. In conclusion, the activity against vascular injuries increased under the presence of defective ability of vascular repair in CKD with moderately impaired renal function. This finding may explain the present therapeutic failure in treating these CKD patients, and imply that treatment at an earlier stage of CKD should be implemented. Show more

Keywords: Angiopoietin, chronic kidney disease, hemodynamic maladjustment, renal microvascular disease vascular homeostasis

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 3, pp. 201-207, 2008

Authors: Michalska-Malecka, Katarzyna | Slowinska, Ludmila | Dorecka, Mariola | Romaniuk, Wanda

Article Type: Research Article

Abstract: The aim of this study was to correlate some pathogenetic factor with the hemorheological parameters in ills with age-related macular degeneration. The studies were performed on 52 patients suffering from AMD. The control group consisted of 42 healthy persons. Blood samples were taken from patients immediately after ophthalmological examination from antecubital vein and anticoagulated with K3 EDTA. The symptoms of macular degeneration were drusen; changes in retinal pigmentation, areolar atrophy, neovascularization. Blood viscosity measurements were performed with use of cone-plate Brookfield viscometer at sheer rate 150 s−1 and plasma viscosity with capillary Ubbelohde's viscometer. Fibrinogen concentration has been measured …according to Clauss method, and level of triglycerides was measured using coupled enzymatic reactions. Haematocrit level was measured with the help of micromethod. The viscosity of whole blood, corrected viscosity and plasma viscosity were respectively 6.9%, 14.6% and 15.7% higher in the patient group than in the control group, while fibrinogen-plasma factor was 16% higher. Aggregation amplitude and time t1/2 were 89.3% and 28.6% lower in AMD group. Erythrocyte deformability was 18% lower. The aggregation index was 7.6% higher in the AMD group then in the control group. Summing up in people suffering from AMD rheological disturbances is observed increased blood and plasma viscosity. Show more

Keywords: Blood viscosity, plasma viscosity, retinal degeneration change, aggregation of red cells, deformability of red cells

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 3, pp. 209-216, 2008

Article Type: Other

Citation: Clinical Hemorheology and Microcirculation, vol. 38, no. 3, pp. 217-218, 2008