The use of nanomechanic sensor for studies of morphofunctional properties of lymphocytes from healthy donors and patients with chronic lymphoblastic leukemia.

Tapping mode-atomic force microscopy and force spectroscopy were used for studies of the topography of the cell surface and elastic properties of lymphocytes from healthy donors and patients with chronic lymphoblastic leukemia. It was demonstrated that the decrease in lymphocytes stiffness in patients with chronic lymphoblastic leukemia by 51.4% (p<0.05) was accompanied by spatial modification of the cell surface, in particular, increase in the number of globular protrusions and depressions by 247 and 122%, respectively (p<0.05), in comparison with normal lymphocytes.

Red blood cell aggregation changes are depended on its initial value: Effect of long-term drug treatment and short-term cell incubation with drug.

This study was designed to investigate whether the red cell aggregation depends on its initial level under drug therapy or cell incubation with bioactive chemical compounds. Sixty six subjects were enrolled onto this study, and sub-divided into two groups: the first group of patients (n = 36) with cerebral atherosclerosis received pentoxifylline therapy (400 mg, thrice daily) for 4 weeks. The patients of the second group were initially treated with Epoetin beta 10,000 units subcutaneously thrice a week, for 4 weeks. The second group - adult anemic patients (n = 30) with the confirmed diagnosis of solid cancer (Hb < 100 g/L). After 4 weeks of pentoxifylline treatment the red cell aggregation increased (p < 0.05) in the patients with initially low RBCA. On the other hand in the patients with initially high RBCA treatment with pentoxifylline reduced it markedly (p < 0.01). In vitro experiments with pentoxifylline RBC incubation resulted in a decrease of the initially high RBCA by 47% (p < 0.01), whereas in the sub-group with initially low RBCA it increased. It was observed that after 4 weeks of epoetin-beta treatment 75% the anemic patients with initially high RBCA had an aggregation lowering. The drop of aggregation was about 34% (p < 0.01). At the same time 25% of the study patients had a significant RBCA increase (p < 0.05) after treatment. The initially low red cell aggregation after incubation with epoetin-beta was markedly increased by 122% (p < 0.05). On the contrary initially high RBCA was reduced by 47% (p < 0.05). When forskolin (10 µM) was added to the RBC suspensions the RBCA was increased in sub-group of subjects with initially low aggregation and it was decreased in sub-group with initially high one. The similar RBCA changes were observed when RBC suspensions were incubated with vinpocetine, calcium ionophore (A23187), Phorbol 12-myristate 13-acetate (PMA) as a protein kinase C (PKC) stimulator. A major finding of this study is that the red cell aggregation effects of some drugs depend markedly on the initial, pre-treatment aggregation status of the patients. These results demonstrate that the different red blood cell aggregation responses to the biological stimuli depend strongly on the initial, pre-treatment status of the subject and the most probably it is connected with the crosstalk between the adenylyl cyclase signaling pathway and Ca2+ regulatory mechanism.

Comparative efficiency and hemorheological consequences of hemotransfusion and epoetin therapy in anemic cancer patients.

The aim of our study was to compare hemorheological consequences of hemotransfusion and recombinant human erythropoetin treatment in anemic cancer patients. Forty anemic patients with solid nonmyeloid malignancies were enrolled in this prospective, open-label study. Both prior to and following treatment (epoetin beta, 10,000 units subcutaneously thrice weekly, for four weeks and transfusion of 400 ml of erythrocyte mass) hemorheological measurements including blood and plasma viscosity, hematocrit (Hct), hemoglobin, red blood cell aggregation (RBCA) and deformability were completed. It was found an increase of Hb from 76.07+/-3.68 g/l to 87.86+/-4.26 g/l after the transfusion. It was accompanied by Hct rise by 25% (from 23.67+/-1.85 to 29.50+/-1.96%, p<0.05). Under these conditions the whole blood viscosity (BV) was increased by 19% (p<0.05). Plasma viscosity did not change markedly. Therefore the main cause of the whole blood viscosity rise was an increase of Hct. After erythrocyte mass transfusion there were some increases of red cell deformability and aggregation (by 7%, p>0.05). Under these conditions the Hct/BV ratio as an index of oxygen transport efficiency was changed after transfusion only slightly. While after four weeks of epoetin treatment the hematocrit/viscosity ratio was raised by 14% (p<0.05), in spite of the high blood viscosity. In addition RBCA decreased (p<0.01) and their deformability was increased by 14% (p<0.05). In vitro microrheological data permit to suggest that epoetin has a direct effect on the microrheological properties of red cells due to activation of the cellular signal transduction system including the tyrosine kinases and phosphatases. Thus, Epoetin beta administered s.c. thrice weekly, during four weeks, increased hemoglobin levels, improved hemorheological profile and especially its microrheological part as well as the blood transport capacity in anemic cancer patients who were receiving chemotherapy and its hemorheological effect was more positive than under hemotransfusion.

Hemorheological changes in solid tumor patients after treatment with recombinant erythropoetin.

The subject of this study was the effect of erythropoetin (Epoetin) treatment of anemic patients (n=30) with solid tumors on parameters of hemorheological profile. Both prior to and following Epoetin treatment (10,000 units subcutaneously thrice weekly) for four weeks hemorheological measurements included plasma and red blood cell (RBC) suspension viscosity; high and low shear whole blood viscosity; hematocrit (Hct), hemoglobin, RBC aggregation (RBCA) and deformation. It was found that the patients had reduced Hb up to 92.96+/-2.99 g/l, and the Hct - 28.2%. These parameters were significant increased after four weeks of Epoetin treatment: Hb by 28% (p<0.01) and Hct by 31% (p<0.01). In macrorheological part of the profile, both the high shear blood viscosity, and the low one were increased by 23 and 27% (p<0.05), respectively. These changes were mainly associated with the Hct rise. As for microrheological part of profile after Epoetin treatment, RBCA was decreased by 25% (p<0.05). While the red cell rigidity index (Tk) was lowered only slightly (by 8%). RBC incubation with Epoetin (10.0 I.E./ml) was accompanied by 10% decrease of Tk. It is important to note that before Epoetin treatment incubation with it led to decrease of RBCA by 30% (p<0.05), whereas after four week of the treatment period a 27% (p<0.05) rise of aggregation was found in majority of patients. Thus these results suggest that Epoetin is an effective, safe and convenient therapy for the management of anaemia in patients with cancer. And this drug has a moderate positive hemorheological effect on RBC and on the microrheological properties in particular. These data suggested that Epoetin has an effect on the membrane properties regulating RBC aggregation and deformation and affects by the signal transduction system, including Ca2+-dependant signaling pathway and tyrosine kinase and phosphotase activity change.

The microrheological behavior of young and old red blood cells in athletes.

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.

Major alterations in body fluid status and blood rheology.

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.

Effects of Ramipril and Isradipin on hemorheological profiles in patients with arterial hypertension.

In this study, the effect of the angiotensin-converting-enzyme inhibitor (ACE inhibitor) Ramipril (5 mg/day) and calcium antagonist Isradipin (5 mg/day) treatment of two groups of hypertensive patients (n = 22 in each of group) was evaluated. The parameters of the hemorheological profile (blood and plasma viscosity, red blood cell aggregation and deformation, plasma protein concentration and its osmolality, hematocrit and ratio of Hct/blood viscosity) were measured in basal conditions (before treatment) and after 3 weeks of treatment. The patients showed some increased blood, plasma viscosity, RBC aggregability and fibrinogen concentration in basal conditions. In both groups of patients, three main parameters of the hemorheological profile (plasma viscosity, Hct and RBC aggregation) decreased after treatment. No significant changes in red cell deformability was found. In conclusion, ACE inhibition with Ramipril and calcium channel blocking with Isradipin lead to a moderate improvement of blood rheology in patients with hypertension. This may be explained by the pronounced vasodilatatory effect of ACE inhibitor and calcium antagonist, though their acting mechanism is different.