Improvement Of Erythrocyte Deformability Research Articles

Ultra-Small Superparamagnetic Iron-Oxide Nanoparticles Exert Different Effects on Erythrocytes in Normotensive and Hypertensive Rats.

We determined erythrocyte physiological and biochemical properties after the single and repeated administration of ultra-small superparamagnetic iron-oxide nanoparticles (USPIONs) in normotensive Wistar–Kyoto (WKY) and spontaneously hypertensive (SHR) rats. Polyethylene glycol-coated USPIONs (transmission electron microscope detected a mean size of ~30 nm and hydrodynamic size ~51 nm) were intravenously administered to rats either in one infusion at nominal dose 1 mg Fe/kg or in two infusions (administered with a difference of 24 h) at nominal dose 2 mg Fe/kg. Results showed that USPIONs did not deteriorate erythrocyte deformability, nitric oxide production, and osmotic resistance in both experimental settings. Both the single and repeated USPION administration elevated erythrocyte deformability in WKY. However, this effect was not present in SHR; deformability in USPION-treated SHR was significantly lower than in USPION-treated WKY. Nitric oxide production by erythrocytes was increased after a single USPION treatment in WKY, so it can be associated with improvement in erythrocyte deformability. Using biomagnetometry, we revealed significantly lower amounts of USPION-originated iron in erythrocytes in SHR compared with WKY. We found a much faster elimination of USPIONs from erythrocytes in hypertensive rats compared with the normotensive ones, which might be relevant for clinical practice in hypertensive patients undergoing clinical examination with the use of iron-oxide nanoparticles.

Effects of different rehabilitation models on erythrocyte deformability and nitrite plus nitrate as end-products of nitric oxide levels in elderly women.

The aim of the present study was to analyze the effects of two rehabilitation protocols, dance movement therapy exercises (DMT) and general rehabilitation exercises (GRE), on erythrocyte deformability and plasma levels of nitrite plus nitrate as end products of nitric oxide (NOx) in elderly women. The study included 39 women aged 61-82years, subjected to either GRE (n=20) or DMT (n=19). Women were subjected to 5-months programs of GRE and DMT, with each session lasting no longer than 45-50min, and the intensity of exercising corresponding to no more than 40-60% of heart rate reserve. Plasma levels of NOx were determined spectrophotometrically before and at the end of the intervention. A significant increase in the total nitrate/nitrite concentration from 1.341μmol/L to 1.590μmol/L (7.3%) was observed in women subjected to the DMT rehabilitation program. Furthermore, an increase in erythrocyte deformability was observed in this group at shear stress 0.30. No significant difference was found between the pre- and post-rehabilitation NOx levels of women participating in the GRE program. Participation in DMT rehabilitation program might be reflected by an increase in plasma NOx levels and an improvement of erythrocyte deformability at lesser shear stress, and thus could potentially result in better vascular function. DMT should be offered to older adults, especially to persons who do not find conventional forms of rehabilitation as attractive, as they might refrain from physical activity and suffer from a faster decline in nitric oxide production. Geriatr Gerontol Int 2017; 17: 2479-2484.

Effects of rhythmic exercise performed to music on the rheological properties of blood in women over 60 years of age

The aim of this study was to analyze the effects of motor rehabilitation, in the form of rhythmic exercise to music, on the rheological characteristics of blood in older women. The study included 30 women (65-80 years of age), and the control group was comprised of 10 women of corresponding age. Women from the experimental group were subjected to a five-month rehabilitation program, in the form of rhythmic exercise performed to music (three 30-minute sessions per week); women from the control group were not involved in any regular physical activity. Blood samples from all the women were examined for hematological, rheological, and biochemical parameters prior to the study and five months thereafter. The rehabilitation program was reflected by a significant improvement of erythrocyte count and hematocrit. Furthermore, an improvement of erythrocyte deformability was observed by lower shear stress levels, while no significant changes were noted by the higher shear stress values. The rehabilitation resulted in a marked decrease of the aggregation amplitude while no significant changes were observed in aggregation index and total aggregation half-time. Additionally, the training regimen was reflected by a significant increase in the plasma viscosity, while no significant changes in fibrinogen levels were noted.

Effects of dexmedetomidine on the deformability of erythrocytes in vitro and in anesthesia.

The current study aimed to evaluate the impact of clinically relevant concentrations of dexmedetomidine on the deformability of erythrocytes in vitro and the effects of dexmedetomidine on the deformability of erythrocytes in patients undergoing laparoscopic cholecystectomy. Erythrocyte suspensions of different concentrations were divided into six groups: Control (group C); low, medium and high concentrations of dexmedetomidine (groups DL, DM and DH, respectively); yohimbine alone (group Y) and yohimbine mixed with dexmedetomidine (group YD). The suspensions were incubated in a thermostatic shaking incubator (50 rpm, 37°C) for 60 min. The nitric oxide (NO) concentrations and endothelial nitric oxide synthase (eNOS) activities of red blood cells and the erythrocyte deformability index (EI) were then measured. Patients (n=40) scheduled for laparoscopic cholecystectomy were randomly divided into a dexmedetomidine group (group A) and a control group (group B). The induction and maintenance of anesthesia in the two groups was identical. The EI and hematocrit (Hct) were assayed prior to anesthesia (T0) and following the surgery (T1). In the in vitro assay, the EI, the activity of eNOS and the NO concentration of the erythrocytes were significantly higher in groups DL, DM, DH and YD than in group C (P<0.05). In addition, the EI, the eNOS activity and NO concentration of the erythrocytes were higher in group DM than in group YD (P<0.05). In the patients, the EI value at T1 (0.90±0.04) was higher than at T0 (0.81±0.06) in group B (P<0.05). No statistically significant difference between the EI values at T0 and T1 was identified in group A (P>0.05). Dexmedetomidine treatment is able to improve the deformability of erythrocytes in vitro and in anesthesia. The improvement of erythrocyte deformability by dexmedetomidine may be partially associated with adrenergic receptors through activation of eNOS to enhance the concentration of NO in red blood cells.

Vildagliptin in addition to metformin improves retinal blood flow and erythrocyte deformability in patients with type 2 diabetes mellitus – results from an exploratory study

Numerous rheological and microvascular alterations characterize the vascular pathology in patients with type 2 diabetes mellitus (T2DM). This study investigated effects of vildagliptin in comparison to glimepiride on retinal microvascular blood flow and erythrocyte deformability in T2DM.Fourty-four patients with T2DM on metformin monotherapy were included in this randomized, exploratory study over 24 weeks. Patients were randomized to receive either vildagliptin (50 mg twice daily) or glimepiride individually titrated up to 4 mg in addition to ongoing metformin treatment. Retinal microvascular blood flow (RBF) and the arteriolar wall to lumen ratio (WLR) were assessed using a laser doppler scanner. In addition, the erythrocyte elongation index (EI) was measured at different shear stresses using laserdiffractoscopy.Both treatments improved glycaemic control (p < 0.05 vs. baseline; respectively). While only slight changes in RBF and the WLR could be observed during treatment with glimepiride, vildagliptin significantly increased retinal blood flow and decreased the arterial WLR (p < 0.05 vs. baseline respectively). The EI increased during both treatments over a wide range of applied shear stresses (p < 0.05 vs. baseline). An inverse correlation could be observed between improved glycaemic control (HbA1c) and EI (r = −0.524; p < 0.0001) but not with the changes in retinal microvascular measurements.Our results suggest that vildagliptin might exert beneficial effects on retinal microvascular blood flow beyond glucose control. In contrast, the improvement in erythrocyte deformability observed in both treatment groups, seems to be a correlate of improved glycaemic control.

Effects of Hyul-Bu-Chuke-Tang on Erythrocyte Deformability and Cerebrovascular CO2Reactivity in Normal Subjects

Aim. Hyul-bu-chuke-tang (HCEt) is a well-known traditional herbal medicine that is used for the treatment of ischemic cerebrovascular disorders. We investigated the acute effects of HCEt on erythrocyte deformability and cerebrovascular CO2 reactivity (CVR) in healthy male subjects. Materials and Methods. We examined erythrocyte deformability in an HCEt group (n = 14) and a control group (n = 10). CVR was measured using hyperventilation-induced CO2 reactivity of the middle cerebral artery and transcranial Doppler (TCD) in the HCEt group (n = 11). A historical control group (n = 10) of CVR measurements was also created from our previous study. All measurements were performed prior to and 1, 2, and 3 hours after HCEt administration. Results. HCEt significantly improved erythrocyte deformability 1 hour after administration compared to the control group (2.9 ± 1.1% versus −0.6 ± 1.0%, P = 0.034). HCEt significantly improved the CVR 2 hours after administration compared to the historical control group (9.1 ± 4.0% versus −8.1 ± 4.1%, P = 0.007). The mean blood pressure and pulse rate did not vary from baseline values in either group. Conclusions. We demonstrated that HCEt improved erythrocyte deformability and CVR. Our findings suggest that an improvement in erythrocyte deformability contributes to HCEt's effect on cerebral microcirculation.

Effects of erythropoietin on erythrocyte deformability in non‐transfused preterm infants

Suppression of erythropoiesis due to low plasma erythropoietin levels is an important factor in the development of anaemia of prematurity. Premature infants may therefore be treated with recombinant human erythropoietin (rhEPO). This prospective, randomised and controlled study was designed to find out whether rhEPO treatment improves erythrocyte deformability in preterm infants. Sixteen infants were treated with rhEPO (250 IU/kg three times weekly) a total of 15 times beginning on day of life 5 whereas fifteen infants served as controls. Haemoglobin concentration, haematocrit, reticulocyte count, ferritin level and erythrocyte deformability were measured on days 5, 14, 28, 42 and 63. Erythrocyte elongation was determined as an indicator of erythrocyte deformability using a shear stress diffractometer (Rheodyn SSD) at shear forces of 0.3 to 60 Pa. Haemoglobin concentration was significantly higher on days 28 and 42 and reticulocyte percentage on day 28 in the rhEPO group compared to the controls. Serum ferritin was lower in the rhEPO group on day 28. Erythrocyte deformability was significantly increased on days 28 and 42 in the infants receiving rhEPO. We found a strong relationship between erythrocyte elongation and reticulocyte count. RhEPO markedly increases the erythropoiesis in preterm infants in the critical first weeks of life and the anaemia of prematurity is obviously reduced. The erythrocyte deformability improved under rhEPO treatment. Erythrocyte deformability was significantly related to the reticulocyte count indicating that the improvement of erythrocyte deformability was due to the formation of well-deformable young erythrocytes.

Microvasculature in acute myocardial ischemia: part I: evolving concepts in pathophysiology, diagnosis, and treatment.

Microvasculature in acute myocardial ischemia: part I: evolving concepts in pathophysiology, diagnosis, and treatment.

Effects of C-peptide on microvascular blood flow and blood hemorheology.

Beside functional and structural changes in vascular biology, alterations in the rheologic properties of blood cells mainly determines to an impaired microvascular blood flow in patients suffering from diabetes mellitus. Recent investigations provide increasing evidence that impaired C-peptide secretion in type 1 diabetic patients might contribute to the development of microvascular complications. C-peptide has been shown to stimulate endothelial NO secretion by activation of the Ca2+ calmodolin regulated enzyme eNOS. NO himself has the potency to increase cGMP levels in smooth muscle cells and to activate Na+ K+ ATPase activity and therefore evolves numerous effects in microvascular regulation. In type 1 diabetic patients, supplementation of C-peptide was shown to improve endothelium dependent vasodilatation in an NO-dependent pathway in different vascular compartments. In addition, it could be shown that C-peptide administration in type 1 diabetic patients, results in a redistribution of skin blood flow by increasing nutritive capillary blood flow in favour to subpapillary blood flow. Impaired Na+ K+ ATPase in another feature of diabetes mellitus in many cell types and is believed to be a pivotal regulator of various cell functions. C-peptide supplementation has been shown to restore Na+ K+ATPase activity in different cell types during in vitro and in vivo investigations. In type 1 diabetic patients, C-peptide supplementation was shown to increase erythrocyte Na+ K+ATPase activity by about 100%. There was found a linear relationship between plasma C-peptide levels and erythrocyte Na+ K+ATPase activity. In small capillaries, microvascular blood flow is increasingly determined by the rheologic properties of erythrocytes. Using laser-diffractoscopie a huge improvement in erythrocyte deformability could be observed after C-peptide administration in erythrocytes of type 1 diabetic patients. Inhibition of the Na+ K+ATPase by Obain completely abolished the effect of C-peptide on erythrocyte deformability. In conclusion, C-peptide improves microvascular function and blood flow in type 1 diabetic patients by interfering with vascular and rheological components of microvascular blood flow.

Influence of adsorbed plasma proteins on erythrocyte rheological properties: in vitro and ex vivo studies.

The influence of plasma protein adsorption on the mechanical properties characterizing erythrocyte behaviour under flow was studied in human and rats. The deformability index, elastic modulus and surface viscosity were measured by laser diffractometry. In in vitro studies, human and rat erythrocytes were washed to remove their original protein coating, and then incubated in saline-diluted plasma media. For erythrocytes incubated in the most diluted solutions (plasma/saline 1:3, v/v), the deformability index increased 30% for both species (human, P<0.01 and rat, P<0.2); the elastic modulus decreased 20% (human, P<0.05) and 60% (rat, P<0.01); and surface viscosity decreased 20% (human, P<0.05) and 40% (rat, P<0.01), relative to values for erythrocytes incubated in pure plasma. Ex vivo experiments were performed using rats. Plasma proteins were diluted replacing 15% volemic plasma by saline in three consecutive plasmapheresis steps. The rheological properties of erythrocytes, tested after each step, followed the general trends of the in vitro pattern. These results suggest that the decrease in plasma protein concentration affects blood rheology in two ways. The first is the well known decrease in plasma viscosity, and the second is an improvement of erythrocyte deformability, as has been shown in this work. Thus, a new argument supporting the benefits of normovolemic hemodilution in patients with poor peripheral perfusion is provided.

Cardiovascular Effect of Trilinolein

Mechanisms for the myocardial protective effect of TL: included improvement of erythrocyte deformability, inhibition of adrenaline-induced platelet aggregation, endothelium-dependent vasorelaxant effect and suppression of neutrophil adhesion to endothelium. Biochemical studies showed that .TL increased cyclic GMP through a stimulation of nitric oxide synthesis. In addition, TL scavenged free radical formation in neutrophils. These beneficial effects of TL on cardiovascular system was not mediated through linoleic acid which was derived from hydrolysis of TL.

Improvement of erythrocyte deformability by cholesterol-lowering therapy with pravastatin in hypercholesterolemic patients

Erythrocyte deformation is an important regulatory factor of the microcirculation. The present study was designed to examine whether erythrocyte deformability is altered in hypercholesterolemic patients and, if so, whether cholesterol-lowering therapy affects this parameter in these patients. The erythrocyte deformability of 37 hypercholesterolemic patients was evaluated before and after 1 year of therapy with pravastatin, an inhibitor of hepatic hydroxymethyl glutaryl coenzyme A reductase, under various shear stresses (4.7, 9.5, 23.6, 47.3, 118.1, and 236.2 dyne/cm 2) using laser diffractometry. At study entry, erythrocyte deformability under 4.7 and 9.5 dyne/cm 2 shear stress, which is actually observed in human vessels, was reduced compared with that in 20 age-matched normocholesterolemic subjects and was inversely correlated with serum cholesterol and low-density lipoprotein (LDL) cholesterol. Pravastatin therapy for 1 year, which reduced serum cholesterol from 288 ± 28 to 223 ± 20 mg/dL, significantly improved erythrocyte deformability by approximately 20%. There was a significant relation between the improvement of erythrocyte deformability and the reduction of serum cholesterol or LDL cholesterol. The results suggest that erythrocyte deformability is reduced in hypercholesterolemic patients, and that long-term cholesterol-lowering therapy can improve reduced erythrocyte deformability, which may contribute to the improvement of organ perfusion.

The Effects of Calcium Channel Blockers on Blood Fluidity

Although vasodilation, direct cardiac actions, or both represent the main properties of calcium channel blockers, there are further pharmacologic effects that may be therapeutically relevant. For example, hemorrheological effects, which have been demonstrated for a variety of calcium antagonists, have received relatively little attention to date. Hemorrheology describes the mechanics of blood and its components. It is of particular interest in the context of cardiovascular disease, as it has been shown that under certain conditions (reduced pump function, impaired vasomotor reserve), parameters of blood fluidity may be crucial for tissue perfusion. Whole-blood viscosity is the dominating factor in large arteries. For geometrical reasons, plasma viscosity and the rheological properties of blood cells may become of paramount importance at the microcirculatory level. In ischemic states, erythrocytes may be depleted of ATP, which they need for maintenance of normal shape and for transformation. This results in rigidification of the red blood cell and hindrance of its passage in the microcirculatory bed. Hence, blood flow deteriorates with the consequence of further unfavorable changes of the "milieu interieur," leading to the induction of a vicious cycle. Although effects on several hemorrheological parameters, for example, whole-blood viscosity, plasma viscosity, and red cell aggregation, can be demonstrated for various calcium channel blockers, the main rheological effects of these compounds are believed to consist in the improvement of erythrocyte deformability. When the ATP-dependent calcium pump is impaired in ischemia, calcium channel blockers may inhibit the slow inward transmembrane calcium flux and prevent the accumulation of intracellular calcium.

Results of hemorheologically active treatment with pentoxifylline in patients with cerebrovascular disease.

Ten patients with acute stroke and impaired erythrocyte deformability received pentoxifylline parenterally in daily doses of 1.2-1.5 g for ten days (Study A). Hemorheologic parameters: erythrocyte aggregation, erythrocyte deformability, plasma viscosity, and yield shear stress were monitored. While plasma viscosity and erythrocyte aggregation did not change significantly, there was marked improvement in erythrocyte deformability and yield shear stress. Nine patients improved clinically, 1 died. In 40 patients with lacunar infarcts (Study B) clinical and hemorheologic data were recorded during a three-month treatment with 800 to 1,600 mg oral pentoxifylline per day. The above-quoted variables, being pathologically altered in comparison with healthy controls, were again monitored. Thirty-six patients completed the study (4 dropouts). Clinically, 34 patients improved during treatment, 2 worsened. Hemorheologic variables, which were pathologically altered at baseline, improved significantly. Improvement of accompanying disturbances in the retinal microcirculation (confirmed by video fluorescence angiography) during therapy indicated a close correlation between hemorheologic factors and microcirculation.

Influence of pentoxifylline on erythrocyte deformability in peripheral occlusive arterial disease.

Impaired red cell deformability has been found in patients suffering from chronic peripheral vascular disorders, the implication being that microcirculatory blood flow is hindered and tissue hypoxaemia is aggravated. Measurement of erythrocyte deformability by a standard filtration technique for whole blood was carried out in 40 young healthy persons, in 25 untreated patients with peripheral occlusive arterial disease and in 25 patients with matching vascular disease, before and after a 6-weeks' oral treatment with 400 mg pentoxifylline 4-times daily. The filtration rates were significantly lower in the patient groups compared to those of healthy volunteers. After the oral administration of pentoxifylline, a significant increase in filtration rates was observed pointing to an improvement in erythrocyte deformability. The findings suggest that by improving erythrocyte deformability pentoxifylline positively influences the microcirculatory blood fluidity, an important factor for efficient therapy in peripheral arterial occlusive disease.