Clinical Hemorheology and Microcirculation - Volume 26, issue 3

Authors: Foresto, Patricia | D'Arrigo, Mabel | Racca, Liliana | Filippini, Fernando | Gallo, Roberto | Valverde, Juana | Rasia, Rodolfo J.

Article Type: Research Article

Abstract: The main objective of the present work was to study modifications in RBC aggregate morphology by analyzing digitized microscopic images and compare them between healthy subjects and patients suffering from essential hypertension. Blood samples were obtained from normal subjects (n=30) and patients suffering from essential hypertension (n=20). RBC aggregate morphology was quantified using direct microscopic observation and numerical analysis of images. ASP (Aggregation Shape Parameter) defined as the ratio of the area of the projected image to its square perimeter was calculated. Other rheological parameters have been determined in order to establish the hemorheological profile of the studied hypertension …states. ASP appears significantly higher (p<0.001) in patients suffering essential hypertension (0.69±0.11) than in normal control subjects (0.25±0.12). RBC aggregation is known to be responsible for the high increase in apparent blood viscosity at low shear rates. By compare ASP values with whole blood viscosity at low rate (2.30 s−1 ) a high correlation was formed between both parameters (Spearman coefficient was 0.8835 and p<0.001). The applied method is simple, direct and quantitative and provides a useful tool for measuring deviations of RBC aggregate morphology. Show more

Citation: Clinical Hemorheology and Microcirculation, vol. 26, no. 3, pp. 137-144, 2002

Authors: Angelkort, Bernhard | Amann, Berthold | Lawall, Holger

Article Type: Research Article

Citation: Clinical Hemorheology and Microcirculation, vol. 26, no. 3, pp. 145-154, 2002

Authors: Brun, Jean‐Frédéric

Article Type: Research Article

Abstract: Hemorheological effects of exercise are a triphasic phenomenon including: (a) short‐term effects (hyperviscosity mostly due to fluid shifts and alterations of erythrocyte rigidity and aggregability); (b) middle‐term effects (i.e., the reversal of acute effects due to plasma volume expansion (autohemodilution) that lowers both plasma viscosity and hematocrit; (c) long‐term effects that further improve blood fluidity, parallel with the classical training‐induced hormonal and metabolic alterations. Red cell rheology during these 3 stages is affected by white cells and oxidant stress. On the other hand, most metabolic and hormonal alterations play a role in exercise‐induced hemorheological changes: among them, blood lactate appears …to have opposite effects according to the training status, since it generally impairs erythrocyte fluidity while it improves it in some subgroups of highly trained athletes, a difference that could be related to membrane monocarboxylate transporter status. Body composition (mostly hydration status and the amount of fat mass) as well as its major hormonal regulating system (the growth‐hormone‐IGF‐I axis) are both markedly modified by training and these modifications are correlated with hemorheology. Nutritional disturbances affecting caloric and proteic intake, lipids, iron, zinc, etc. also modulate the hemorheologic effects of exercise. The overtraining syndrome represents a situation of unbalance between body's possibilities, nutrition, and work load, and is associated with metabolic, hormonal, immunologic and hemorheologic disturbances. The clinical relevance of these data is underlined by studies showing that exercise training in patients suffering from metabolic and/or cardiovascular disorders (such as the insulin resistance syndrome) results in a parallel improvement of metabolism, risk factors, blood rheology and fitness. Hemorheological measurements require to be studied, at least as sensitive markers of training, and possibly as “true” risk factors highly sensitive to exercise intensification. Show more

Keywords: Blood viscosity, hematocrit, exercise, VO$_{2\max}$, training, overtraining, metabolic fitness, hemorheology, erythrocyte deformability, erythrocyte aggregation, blood lactate

Citation: Clinical Hemorheology and Microcirculation, vol. 26, no. 3, pp. 155-174, 2002

Authors: Caillaud, Corinne | Connes, Philippe | Bouix, Didier | Mercier, Jacques

Article Type: Research Article

Abstract: Exercise‐induced arterial hypoxemia (EIAH), i.e., a significant drop of O2 arterial partial pressure during sea level exercise, has been shown in both aerobically trained athletes and athletic animal species. The mechanisms potentially involved include ventilation/perfusion inequality and/or pulmonary diffusing capacity limitation. In thoroughbred horses, EIAH is going with pulmonary haemorrhage (EIPH). Stress failure of pulmonary capillaries leading to diffusion limitation has been proposed. Indeed, during intense exercise, the increased cardiac output and blood viscosity combine to rise capillary wall stress. Blood rheology may participate to the increase of $\dot{\mathrm{V}}$ A/$\dot{\mathrm{Q}}$ mismatch and capillary wall stress. High …level of hematocrit (Hct) are known to alter blood flow distribution and rise shear stress in pulmonary capillaries. Any change in red blood cells (RBC) deformability may lead to aggregation at low shear rate, in post capillary veinules. There are contrasting data regarding the effects of blood rheology on EIPH in horses, however the large augmentation of hematocrit during exercise may cause vessel wall stress. In humans, greatest increase in hematocrit may participate to EIAH as well as RBC deformability. Today there is no consensus opinion and further studies of blood rheology in athletes is a field of interest. Show more

Keywords: Blood viscosity, hematocrit, pulmonary gas exchange, horses

Citation: Clinical Hemorheology and Microcirculation, vol. 26, no. 3, pp. 175-181, 2002

Authors: Muravyov, A.V. | Draygin, S.V. | Eremin, N.N. | Muravyov, A.A.

Article Type: Research Article

Abstract: Previous studies have shown a difference in rheological properties of young versus senescent RBCs. There are data that the athletes blood has more young RBCs than untrained people. Our research was a comparative study of the microrheological properties of young and old RBCs in athletes and in untrained people that was as control group. In athletes (men, n=24) and group of the control (men, n=20) the following parameters were measured: RBC aggregation (ARBC; Myrenne aggregometer) and deformability, RBC suspension and plasma viscosity as well as osmolarity, albumin, globulin and fibrinogen concentration, MCHC. Red cells were density (i.e., age) fractionated by …the method of Murphy. After centrifugation the top 10% of the packed cell column (RBCtop, relatively young cells) and the bottom 10% (RBCbot, relatively old cells) were resuspended at 40.0±0.4% (in plasma) for aggregation, deformation and suspension viscosity measurements. It was found significant difference in aggregation and rigidity of the all RBC subpopulations between athletes and control group. The difference in aggregation was associated with reduced fibrinogen and increased ratio albumin/globulin in athletes. Besides, the correlation between aggregation RBCtop and RBCbot with fibrinogen was decreased in athletes. It was one of the cause of high fluidity of the RBCtop‐ and RBCbot suspensions and whole blood in athletes and more effective oxygen transport than in untrained people. Show more

Keywords: Red blood cells, cell aging, aggregation, deformation, athletes

Citation: Clinical Hemorheology and Microcirculation, vol. 26, no. 3, pp. 183-188, 2002

Authors: Temiz, Aysegul | Yalcin, Ozlem | Resmi, Halil | Baskurt, Oguz K.

Article Type: Research Article

Citation: Clinical Hemorheology and Microcirculation, vol. 26, no. 3, pp. 189-193, 2002

Authors: Tikhomirova, I.A. | Muravyov, A.V. | Levin, V.N.

Article Type: Research Article

Abstract: Since the dehydration causes a loss of body water, we studied the rheological properties of blood in the course of water deprivation. Subjects used in this study were 64 white male rats divided into 4 groups: control (n=19) and 3 experimental groups which underwent water deprivation for 3 days (n=15), 6 days (n=15) and 10 days (n=15). The results obtained indicate that under dehydration animals have higher blood and plasma viscosity and erythrocyte aggregation index than in the control group. After 3 days of dehydration these changes are due to the loss of intravascular water. The water deprivation for 10 …days causes significant disturbances in blood composition as well as changes of red blood cell membrane properties whereas blood and plasma volume return to control values. Show more

Keywords: Blood viscosity, dehydration, erythrocyte aggregation, body water, blood composition

Citation: Clinical Hemorheology and Microcirculation, vol. 26, no. 3, pp. 195-198, 2002

Authors: Yu, Hongmei | Zeng, Yanjun | Hu, Jinlin | Li, Caixia

Article Type: Research Article

Abstract: In this study we investigated the patterns of fluid shear stress on induction of monocyte chemoattractant protein‐1 (MCP‐1) secretion in cultured human umbilical vein endothelial cells (HUVECs). MCP‐1 is a potent special chemoattractant, which recruits monocytes into the sub‐endothelium. This process is one of the early events of atherosclerosis. We examined the pattern of fluid shear stress inducing the secretion of MCP‐1 in cultured HUVECs from the view of biomechanics. In our experiments, HUVECs were subjected to controlled levels of shear stress (4, 10, 20 dyn/cm2 ) in a parallel plate flow chamber. MCP‐1 in HUVECs of different periods was …measured by an immunohistochemistry method and digital image analysis; MCP‐1 in perfusion was measured by sandwich ELISA. The results demonstrated the increase of MCP‐1 synthesis and secretion by shear stress was time‐ and force‐dependent. The accumulated level of MCP‐1 in HUVECs under lower shear stress (4 dyn/cm2 ) for 4–5 hrs was 3‐fold compared with that for static cells. When the shear stress lasted to 6 hrs, the secretion of MCP‐1 was reduced to normal levels and could not be increased even when the shear stress lasted for 12 hours. 10 dyn/cm2 had less effect on the secretion of MCP‐1 compared with 4 dyn/cm2 . This research provides data for understanding the mechanism of the contribution of hemodynamic forces to atherosclerosis. Show more

Keywords: Fluid shear stress, atherosclerosis, human vein umbilical endothelial cells (HUVECs), monocyte chemoattractant protein‐1 (MCP‐1)

Citation: Clinical Hemorheology and Microcirculation, vol. 26, no. 3, pp. 199-207, 2002

Authors: Aïssa Benhaddad, A. | Monnier, J.F. | Fédou, C. | Micallef, J.P. | Brun, J.F.

Article Type: Research Article

Abstract: The GH–IGF axis has been recently suggested to modulate blood rheology in trained athletes, via GH effects on body water status and a possible action of IGF‐I on erythrocyte deformability and aggregability. Another potential candidate for such a rheologic effect of the GH–IGF axis is insulin‐like growth factor binding protein‐1 (IGF‐BP1) which is increased in trained people and correlated to fitness: IGF‐BP1 is elevated in patients with polycythemia vera and stimulates erythroid burst formation in vitro. We investigated the statistical relationships between IGF‐BP1 and blood rheology in athletes. 21 soccer players, age 24.5±1.13 yr; body mass index 23.7±0.38 kg/m2 ; …VO2max  44.8±7 ml.min−1 .kg−1 ). The major statistical determinant of IGFBP1 (measured at rest after overnight fast) was age (r=0.752, p=0.00013) which was not correlated with rheological parameters. IGF BP1 was negatively correlated with blood viscosity η (high shear rate r=−0.516, p=0.024) and positively correlated with the percentage of extracellular water in total body water (ECW/TBW) (r=0.488, p=0.039). The previously reported correlations between IGF‐I and both η (r=0.637, p=0.003) and red cell rigidity “Tk” (r=0.696, p=0.0137) were observed, but IGF‐I and IGF‐BP1 were not correlated to each other (r=−0.176 ns) and their correlations with η and Tk appeared to be independent when studied by multivariate analysis. Consistent with these correlations, subjects in the upper tertile of IGF‐BP1 (>23.4 ng/ml) compared to those in the lower (<7.5 ng/ml) had a higher percentage of ECW/TBW (40.8±0.4 vs 38±0.8%, p=0.033), a lower η (2.7±0.05 vs 2.97±0.06 mPa.s, p=0.016), and a lower Tk (0.54±0.05 vs 0.63±0.01, p=0.027). Thus, beside GH and IGF‐I, IGF‐BP1, which is reported to act on erythroid progenitors, exhibits statistical relationships with blood fluidity and erythrocyte flexibility that may suggest a physiological role in improving blood rheology. Show more

Keywords: Blood viscosity, hemorheology, erythrocyte deformability, erythrocyte aggregability, exercise training, overtraining, insulin‐like growth factor binding protein 1, insulin‐like growth factor binding protein 3, insulin‐like growth factor I, growth hormone, body fluids

Citation: Clinical Hemorheology and Microcirculation, vol. 26, no. 3, pp. 209-217, 2002