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PubMed2003

Influence of a parenteral fish-oil preparation (Omegaven) on erythrocyte morphology and blood viscosity in vitro.

In most studies fish-oil had been administered by enteral route. Recently an parenteral marine fish-oil emulsion has been developed. With an intravenous infusion an immediate effect on the membrane lipid composition of circulating blood cells and endothelial cells may be expected. In this study we assessed the acute effects of a parenteral fish-oil emulsion on blood rheology and erythrocyte morphology in vitro. Blood from 15 healthy young volunteers was incubated in vitro with increasing concentrations of a parenteral fish-oil emulsion (Omegaven) at 37 degrees C for different time periods (2, 20, and 60 min). Plasma and whole blood viscosity were measured using a Couette viscometer. Red blood cell morphology was examined by light and scanning electron microscopy. High plasma concentrations of Omegaven increased whole blood viscosity at high and low shear rate (p<0.01 above 20%vol) and plasma viscosity to a lower extent (p<0.05 at 40%vol). Erythrocytes underwent cell swelling (increase of centrifuged hematocrit) and a dose-dependent echinocytic shape transformation, which indicates an intercalation of the compound in the outer hemileaflet of the cell membrane. These effects were already apparent after 2 min of incubation and were fully reversible upon wash-out of Omegaven. We conclude that the intravenous fish-oil preparation Omegaven interacts with the outer hemileaflet of the erythrocyte membrane and may affect membrane functions. At pharmacological concentrations these effects seem to be negligeable.

Adult↗
PubMed1983

Effect of treatment on retinal circulation, platelet aggregation and blood viscosity in insulin-dependent and noninsulin-dependent diabetics.

In order to investigate the influence of diabetic treatment, especially insulin treatment on diabetic retinopathy, disc-to-macula circulation time, platelet aggregation and blood viscosity were observed before and after treatment for 5 years in 42 diabetics (17 insulin-dependent diabetics [IDD] and 25 noninsulin-dependent diabetics [NIDD]). The disc-to-macula circulation time was significantly correlated with the mean blood glucose level. The platelet aggregation in IDD was enhanced significantly as compared with that in NIDD, however after treatment with insulin, the platelet aggregation revealed a significant decrease in IDD. The inter-period changes in the disc-to-macula circulation time before and after treatment in IDD were correlated with those of platelet aggregation, but not with those of blood viscosity. These results suggested that although the blood glucose level was considered to be one of the important factors influencing the retinal circulation, insulin had a direct effect on the platelet function in improving the retinal circulation in addition to lowering the blood glucose level.

Adult↗
PubMed2005

[A drop in "apparent" blood viscosity due to administration of high-molecular polymer capable of augmenting viscosity].

Influence of a high-molecular compound capable of augmenting viscosity, namely: polyethylene oxide Polyox WSR-301, on hemodynamic parameters in rat mesenteric microvessels was investigated. A substantial decrease in the arteriolar hemodynamic resistance caused by the polymer was revealed. Special research has shown that this reaction is not connected with a vasodilatation and, therefore, is caused by a reduction in the "apparent" viscosity of the blood, i.e., it is a consequence of changed properties of the blood flow.

Animals↗
PubMed2002

[Effects of nebivolol on microcirculation, platelet aggregation and blood viscosity in patients with essential hypertension].

AIM: To assess effects of a selective beta1-adrenoreceptor blocker acting in part via nitric oxide nebivolol on microcirculation, platelet aggregation and blood viscosity. MATERIAL: Thirty patients with mild-to-moderate essential hypertension (mean age 54,1-/+9,3 years). METHODS: Ambulatory blood pressure monitoring, laser doppler flowmetry, registration of spontaneous and ADP-induced platelet aggregation. Nebivolol (5 mg/day) or its combination with hydrochlorothiazide (12,5 mg/day) were given for 3 months. RESULTS: Treatment with nebivolol caused significant reduction of systolic and diastolic blood pressures. Spontaneous and low dose ADP-induced platelet aggregation significantly decreased during treatment while blood viscosity did not change. In patients with hyperemic and spastic-hyperemic hemodynamic type of microcirculation improvement of microcirculation occurred due to changes of myogenic tone of arterioles and precapillary sphincters and 'damping' properties of resistance arterioles. CONCLUSION: In patients with essential hypertension hypotensive action of nebivolol was associated with antiaggregation effect and improvement of blood flow in microvascular networks.

Adult↗
PubMed1989

Blood viscosity in human obesity: relation to glucose tolerance and insulin status.

Obesity is known to be associated with an elevated risk for cardiovascular disease. Rheological disturbances could be factors contributing to these vascular complications. Therefore we have evaluated blood viscosity parameters in 128 obese (BMI greater than 28 kg/m2) adults and in 90 non-obese healthy subjects. Whole blood, plasma and erythrocyte viscosity values were determined with a Contraves LS30 viscosimeter. Plasma and whole blood viscosity were significantly (all P less than 0.001) increased in the obese subjects. The increased low shear erythrocyte viscosity suggested a diminished erythrocyte deformability in obesity. The rheological abnormalities were present even in the absence of impaired glucose tolerance, diabetes, hypertension or hyperlipidaemia. In the obese group the rheological parameters showed significant correlations (at least P less than 0.05) with BMI, insulin or C-peptide area during an oral glucose tolerance test and plasma lipids. Our findings demonstrate that obesity per se may be associated with abnormal blood viscosity properties.

Adult↗
PubMed2005

Association of blood pressure with blood viscosity in american indians: the Strong Heart Study.

Abnormalities in whole blood viscosity (WBV) have been implicated in hypertension. This study analyzes relations between WBV and blood pressure in the Strong Heart Study population of American Indians. We examined 676 participants (489 women, age 62+/-7 years) without prevalent cardiovascular disease or use of antihypertensive medications, digoxin, or aspirin. WBV was calculated from hematocrit and plasma protein concentration, at a shear rate of 208 seconds(-1), by a validated equation. Forty eight percent of participants were obese, 43% had diabetes, 19% had hypertension, and 30% were current smokers. WBV was higher in men, smokers, and participants with central obesity, but it was not associated with hypertension or diabetes, even accounting for confounders. After adjusting for gender, age, center, smoking, obesity, diabetes, and plasma creatinine, WBV was negatively related to pulse pressure (beta=-0.13; P<0.001) and systolic pressure (beta=-0.09; P<0.02), mainly because of negative relations with hematocrit (beta=-0.11 and -0.10). Among hypertensive individuals, pulse pressure was positively related to age, diabetes, and female gender but not to WBV (multiple R=0.63; P<0.0001); in contrast, in normotensive individuals, pulse pressure was related negatively to WBV or hematocrit, independent of body mass index, without relation to diabetes (R=0.42; P<0.0001). Thus, under normal physiological conditions, in vivo WBV is negatively related pulse pressure. In contrast, the presence of arterial hypertension makes this relation less evident.

Aged↗
PubMed1997

Effects of early heat exposure on thermoregulatory responses and blood viscosity of broilers prior to marketing.

1. This study was to determine the effects of heat load early in life on thermoregulatory responses and whole blood viscosity of broilers during a subsequent exposure to high environmental temperature later in life. 2. The birds, which had been subjected to exposure to 38 degrees C for 24 h at 5-d-old, served as prior exposure group (group A). Both group A and control group B were exposed to 33 degrees C for 3 h when near marketable weight. 3. On exposure to 33 degrees C, although there were no significant differences in the increases in heat production (HP) between the two groups, abdominal temperature (Ta), temperature of external ear tract (Tee), shank skin temperature (Tss), standing-lying frequency and lying time were lower in group A than in group B. Heart rate (HR) and comb surface temperature (Tcs) did not differ but increased in both groups during exposure to 33 degrees C. Respiration rate (RR) was greater in group A. 4. Blood viscosity decreased markedly in both groups after exposure to 33 degrees C; the decrease was greater in group A. 5. These results suggest that early exposure may promote broilers' ability to cope with the subsequent heat load by altering thermoregulatory physiological responses and behavioural patterns, resulting in an alleviation of heat stress.

Aging↗
PubMed2000

Blood viscosity, plasma adrenaline and fasting insulin in hypertensive patients with left ventricular hypertrophy. ICARUS, a LIFE Substudy. Insulin CARotids US Scandinavica.

We have seen relationships between whole blood viscosity (WBV) and components of the metabolic cardiovascular syndrome in borderline hypertensive young men and suggested that sympathetic nervous system (SNS) activity may be a mediator. In the present study we aimed to test this hypothesis in established hypertension and to investigate the relationship between WBV and cardiac dimensions. Unmedicated patients (n = 42) with stage II-III hypertension and electrocardiographic left ventricular hypertrophy (LVH) underwent hyperinsulinemic isoglycemic glucose clamp to assess glucose disposal rate (GDR) and echocardiographic studies. WBV, plasma catecholamines and insulin were measured in arterialized venous blood. WBV at high shear rate correlated with baseline plasma adrenaline (r = 0.33, p = 0.04) and fasting insulin (r = 0.34, p = 0.04) while there was a negative trend for GDR (r = -0.21, p = 0.2). WBV at low shear rate correlated with plasma adrenaline (r = 0.49, p = 0.002) and resting heart rate (r = 0.36, p = 0.02). WBV was higher in smokers than in non-smokers (p = 0.02) and in males than in females (p = 0.02). Fasting insulin independently explained 12% of the variation in WBV at high shear, while baseline adrenaline independently explained 17% of the variation in WBV at low shear. Systolic blood pressure explained 31% of the variation in LV mass index. Thus, we demonstrate positive relationships between blood viscosity versus plasma adrenaline and fasting insulin in hypertensive patients with LVH. We suggest that adrenergic activity may increase hematocrit and viscosity and hence reduce insulin sensitivity.

Aged↗
PubMedDate not supplied

Arterial and venous blood viscosity in ischemic lower limbs in patients affected by peripheral obliterative arterial disease.

Blood, plasma and serum viscosity, packed red cell volume, and plasma fibrinogen concentration was measured in a group of 13 subjects, suffering from peripheral obliterative arterial disease of the lower limbs (stage III or IV), awaiting surgery, and in 9 control subjects, none of whom showed signs of circulatory disease of the lower limbs either by clinical examination or by instrumental measurements. The blood samples were taken from the: (a) antecubital vein; (b) femoral vein; (c) femoral artery. In the patients venous blood viscosity was significantly higher than arterial blood viscosity. No significant differences have been found between the femoral and the antecubital vein, but in the femoral vein blood viscosity was slightly higher. Packed red cell volume and plasma viscosity were slightly but significantly higher in venous blood, while no difference was seen in serum viscosity and in plasma fibrinogen concentration. In the control subjects blood viscosity values were decidedly lower than in patients and no statistically significant differences were to be found between artery and vein, even if viscosity values were lower in artery. These results support the hypothesis that an interrelation exists between hyperivscosity syndrome and vascular ischaemia-inducing diseases.

Adult↗
PubMed1975

Blood viscosity factors and occlusive arterial disease in renal transplant recipients.

29 cadaveric renal transplant recipients were assessed clinically for evidence of occlusive arterial disease prior to undergoing blood viscosity studies. Nineteen patients had manifest arterial disease (myocardial infarction, cerebral thrombosis, angina, intermittent claudication, absent peripheral pulses), while ten were free from vascular complications. Patients with arterial disease showed significant elevations of plasma viscosity (p less than 0.005), aggregation of red cells measured both at 37 and 20 degrees C (p less than 0.05), fibrinogen (p less than 0.005), serum triglyceride (p less than 0.01), serum cholesterol (p less than 0.01), erythrocyte sedimentation rate (p less than 0.02), and a significant reduction in the albumin/fibrinogen ratio (p less than 0.005) when compared with those free of disease. Two patients with no apparent vascular disease when investigated were found to have distinctly abnormal blood viscosity factors, and one subsequently developed retinal arterial thrombosis while the other suffered serious damage of the graft within 3 months of viscosity study. When all patients were considered together, significant correlations were found between viscosity of artificial thrombi or aggregation of red cells and fibrinogen level (both p less than 0.05), and serum triglyceride level (both p less than 0.05); and between rigidity of red cells and the parathyroid hormone level (p less than 0.01).

Adult↗
PubMed2005

Blood viscosity: effects of mental stress and relations to autonomic nervous system function and insulin sensitivity.

We studied effects of mental stress on whole-blood viscosity (WBV) and blood pressure (BP), and relations between WBV and autonomic nervous system activity and insulin sensitivity. We measured WBV (rotational rheometer), plasma noradrenaline (NA), finger BP, heart rate variability (HRV) and baroreflex sensitivity (BRS; transfer technique) during hyperinsulinaemic glucose clamp and mental arithmetic stress test (MST) in 20 men with high ( > or =140/90 mmHg) and 21 men with normal (< or =115/75 mmHg) screening BP, and 10 women regardless of screening BP (all normotensive). WBV and NA increased during the MST, while HRV and BRS decreased. During the MST, WBV (all shear rates) and the response ((delta)WBV) (low shear) were higher in men with high compared to normal screening BP (p<0.05). In men, WBV correlated positively with NA and negatively with HRV, BRS and insulin sensitivity. The diastolic BP response ((delta)DBP) was independently explained by high-shear (delta)WBV (p<0.05) and (delta)NA (p<0.0001), and (delta)WBV independently by (delta)DBP (p<0.05). WBV is related to increased sympathetic activity, impaired vagal cardiac control and low insulin sensitivity in young adults. The haemorheological effect of mental stress is increased in young men with high screening BP and may be mediated by the acute increase in BP.

Adult↗
PubMed1985

[Blood viscosity and the pressure limit of whole blood in patients with a vascular form of vibration disease].

Eighty-two men suffering from the vascular form to the vibration disease have been divided into two groups pursuant to advancement of the disease: group I consisting of 42 persons (average age 40 +/- 7.5 years) representing an early stage of the disease, and group II consisting of 40 persons (average age 49,7 +/- 5,6 years)--at an advanced stage of the disease. In both groups the variation of apparent viscosity with shear rate (rheological equations), plastic viscosity and yield stress of the whole blood have been determined. The control group consisted of 100 healthy men (average age 41.3 +/- 8.4 years), classified as medium-hard working (group III). Those afflicted with the vascular form of the vibration disease have been found to exhibit viscosity and yield stress of the whole blood, the increase varying with advancement of the disease.

Adult↗
PubMed1989

Peripheral hemodynamics, blood viscosity, and the renin-angiotensin system in hemodialysis patients under therapy with recombinant human erythropoietin.

Treatment of renal anemia with rhEPO (120 U/kg body weight/hemodialysis) in transfusion-dependent patients on maintenance hemodialysis led to an increase in blood pressure, regional peripheral resistance and whole blood viscosity. Our results are in agreement with earlier findings that partial correction of renal anemia results in hemodynamic changes characterized by a fall in cardiac output together with an increase in blood pressure due to increased vascular resistance. The increase in whole blood viscosity correlated with the increase in regional peripheral resistance but not with the increase in mean arterial blood pressure. Thus, other regulating factors of vascular resistance must be involved. Correction of renal anemia does not influence the reninangiotensin system. However, peripheral responsiveness of vascular smooth muscles may have changed due to improved tissue oxygenation and thus leading to an increase in vasoconstriction.

Adult↗
PubMed1985

The effects of dietary omega-3 polyunsaturated fatty acids on erythrocyte membrane phospholipids, erythrocyte deformability and blood viscosity in healthy volunteers.

We have examined, in normal subjects, the effects of a daily dietary supplement of fish oil concentrate ('maxEPA'), providing 3 g of omega-3 fatty acids, on erythrocyte membrane phospholipids, erythrocyte deformability and blood viscosity. After 3 weeks, incorporation of C20:5 omega 3 into erythrocyte phosphatidyl choline (PC) was greater compared to phosphatidyl ethanolamine (PE) and phosphatidyl serine (PS). After 6 weeks, there was no further increase in total erythrocyte C20:5 omega 3, but its distribution amongst phospholipid subclasses had changed. C20:5 omega 3 had increased further in PE and PS, but decreased in PC. Incorporation of C20:5 omega 3 also occurred into PC, PE and PS. omega-3 Fatty acids were incorporated almost entirely at the expense of C18:2 omega 6, but total unsaturation of phospholipids was increased. This is consistent with increased lipid fluidity, which may be an important determinant of erythrocyte deformability. The same dosage of maxEPA also resulted in a significant increase in erythrocyte deformability and a concomitant reduction in whole blood viscosity. Since plasma viscosity and haematocrit were unchanged it seems likely that the effects on blood rheology were mediated by changes in erythrocyte lipid fluidity. Modification of blood rheology by dietary omega-3 fatty acids is of potential value in the treatment of vascular disease.

Blood Viscosity↗
PubMed2000

Relationships between blood viscosity and insulin-like growth factor I status in athletes.

Exercise training is known (1) to enhance the function of the GH-IGF-I system, which has profound effects on body fluid status; (2) to increase blood fluidity. Thus, we investigated during an exercise-test in 39 male elite sportsmen (age 23.7+/-0.72 years; body mass index 23.7+/-0.28 kg/m2) the possible relationships between GH and IGF-I status and the rheological properties of blood. Two correlations indicate a relationship between body hydration and fitness: isometric handgrip strength is correlated with the percentage of extracellular water in total body water (r = 0.432, p = 0.02) and the aerobic working capacity W170 is negatively correlated with hematocrit (r = -0.341, p = 0.039). Water loss during exercise appears to be inversely related to fitness as evaluated by W170 (r = -0.529, p = 0.05), and is positively correlated with the score of signs of overtraining (r = 0.725, p = 0.003) and with the red blood cell aggregation index (r = 0.584, p = 0.036). Finally, while the GH peak value is correlated with the extracellular water volume (r = 0.393, p = 0.02), IGF-I is correlated with blood viscosity (r = 0.546, p = 0.0003), suggesting that when IGF-I values are within the upper quintile (>340 ng/ml) IGF-I may unfavourably affect blood rheology. Among factors of blood viscosity, IGF-I exhibits a borderline correlation (p = 0.05) with "Tk" and the ratio IGF1/IGFBP3 which reflects free circulating IGF-I is correlated with red cell aggregability measured with the Myrenne "M" (r = 0.485, p = 0.014) and S60 (r = 0.396, p = 0.494). These findings confirm the importance of hydration and dehydration as determinants of both blood rheology and exercise performance. Moreover, they suggest that values of IGF-I within the upper quintile are associated with an impairment of blood fluidity, possibly due to a direct effect of IGF-I on red cell deformability and aggregability.

Adult↗
PubMed2006

Plasma lipids and blood viscosity in patients with cerebrovascular disease.

It is known that plasma lipids could increase the cerebrovascular risk through alteration of the hemorheological profile. The aim of the study was to evaluate the relationship between blood viscosity parameters and plasma lipids in patients with cerebrovascular disease (CVD). The study included 43 patients with transient ischemic attacks (TIAs), 53 patients with chronic unilateral cerebral infarctions (UCI) and 57 patients with risk factors (RF) for CVD. Whole blood viscosity (WBV) at different shear rates by Couette rotational viscometer Contraves Low Shear 30, plasma viscosity (PV) with capillary viscometer, hematocrit (Hct), fibrinogen (Fib), Cholesterol (Chol), triglycerides (Tg) and high-density lipoproteins (HDL) were examined in all patients and in a control group of 56 presumed healthy subjects. The hemorheological results showed increase of Hct, Fib, WBV and PV in the patients with TIAs and UCI; it was more pronounced in the UCI patients. Significant increase of Hct and WBV in the group with RF for CVD was also found. The elevation of Chol and Tg predominated in the patients with UCI and in the subjects with RF for CVD. These lipid variables correlated significantly with PV in the TIAs and RF for CVD groups. Conclusion is drawn about the significance of plasma Tg for decrease of blood fluidity and for impairment of the cerebral circulation in CVD.

Aged↗
PubMed1998

No influence of furosemide on human erythrocyte shape and volume and blood viscosity in vitro.

Furosemide is a diuretic agent which is often given in high concentration intravenously. Since erythrocytes have a furosemide-sensitive transport system and oral application of furosemide was found to induce an echinocytic shape transformation in horses, we have analysed the influence of furosemide on erythrocyte shape, volume and blood viscosity in vitro. Increasing plasma furosemide concentrations of 0, 1, 10, 100 and 1000 micrograms/ml did not affect the erythrocyte volume or shape and left blood viscosity unaffected. We conclude that furosemide has no influence on blood rheology in humans.

Administration, Oral↗