Effects of simulated microgravity (HDT) on blood fluidity

Exposures to microgravity and head-down tilt (HDT) produce similar changes in body fluid. This causes an increase in hematocrit that significantly affects hemorheological values. Lack of physical stimulation under bed rest conditions and the relative immobility of the crew during spaceflight also affects the blood fluidity. A group of six healthy male subjects participated as volunteers, and blood samples were collected 10 days before, on day 2 and day 9, and 2 days after the HDT phase. Blood rheology was quantified by plasma viscometry, red cell aggregability, and red cell deformability. A reduced red cell deformability, an indication of the diminished quality of the red blood cells, was measured under HDT conditions that finally led to the so-called “space flight anemia.” Enhanced red cell membrane fragility induced by diminished physical activity and an increase in hemoglobin concentration are responsible for this effect. Plasma viscosity is reduced as a result of diminished plasma proteins. However, despite the reduction in plasma proteins, including fibrinogen, alpha 2-macroglobulin, and immunoglobulin M, red cell aggregation was enhanced, principally because of the increase in hematocrit. Our results of hemorheological alterations under HDT conditions may help to elucidate the formerly documented hematologic changes during spaceflight.

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Viscidation of Blood during Short Term Bed Rest – Its Possible Importance in the Etiology of Deep Vein Thrombosis

Phlebology The Journal of Venous Disease ◽

10.1177/026835558900400106 ◽

1989 ◽

Vol 4 (1) ◽

pp. 31-35

Author(s):

E. Ernst ◽

T. Saradeth ◽

I. Magyarosy ◽

A. Matrai

Keyword(s):

Body Weight ◽

Blood Viscosity ◽

Venous Blood ◽

Bed Rest ◽

Cell Aggregation ◽

Plasma Viscosity ◽

Red Cell ◽

Cell Deformability ◽

Red Cell Deformability ◽

Red Cell Aggregation

Twelve male volunteers were submitted to strict bed rest. Before, 36 hours, and 84 hours after the start of immobilisation venous blood was drawn. Blood viscosity, haematocrit, plasma viscosity, red cell aggregation, red cell deformability, blood pressure, heart rate and body weight were determined. Results show marked haemoconcentration with significant elevations of blood viscosity, haematocrit, plasma viscosity and red cell aggregation during bed rest. Body weight declines by more than 1 kg. It is suggested that haemoconcentration reduces the fluidity of blood, which in turn decreases flow, thereby predisposing to venous thrombosis in clinical situations with bed rest

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The Effects of Acute Smoking on Platelet Behaviour, Fibrinolysis and Haemorheology in Habitual Smokers

Thrombosis and Haemostasis ◽

10.1055/s-0038-1660996 ◽

1984 ◽

Vol 51 (01) ◽

pp. 006-008 ◽

Cited By ~ 96

Author(s):

J J F Belch ◽

B M McArdle ◽

P Burns ◽

G D O Lowe ◽

C D Forbes

Keyword(s):

Platelet Aggregation ◽

Factor Viii ◽

Plasminogen Activator ◽

Arterial Thrombosis ◽

Plasma Viscosity ◽

Red Cell ◽

Cell Deformability ◽

Red Cell Deformability ◽

Cigarette Smokers ◽

Smoking Group

SummaryThere is an increased frequency of arterial thrombosis in cigarette smokers. The changes in blood coagulation seen in these subjects have been studied by many workers but results have not always been in agreement. We wished to study the effects of acute .smoking on platelet behaviour, fibrinolysis and haemorheology in ten habitual smokers, and to compare these results with nonsmoking controls. Results show that the smoking group had higher plasma fibrinogen (p <0.04), lower plasminogen (p <0.02) and plasminogen activator (p <0.05), and higher plasma viscosity (p <0.003). The changes seen in cigarette smokers after smoking three cigarettes were an increase in the rate of platelet aggregation to ADP (p <0.02), an increase in α2M, (p <0.02), and factor VIII RAG (p <0.05). Plasma viscosity was decreased (p <0.02) as was red cell deformability (p >0.02).We confirm an increased tendency to hypercoagulability in smokers compared to controls which becomes more pronounced immediately after smoking three cigarettes.

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Development of Vascular Complications in Diabetes

Vascular Medicine ◽

10.1177/1358863x9700200209 ◽

1997 ◽

Vol 2 (2) ◽

pp. 132-142 ◽

Cited By ~ 30

Author(s):

Donald E McMillan

Keyword(s):

Vascular System ◽

Tangential Force ◽

Vascular Complications ◽

Cell Aggregation ◽

Membrane Curvature ◽

Diabetic Patients ◽

Red Cell ◽

Cell Deformability ◽

Red Cell Deformability ◽

Type Iv

Chronic complications of diabetes are dominated by disorders of the vascular system. They are a much larger burden on both diabetic patients and overall medical costs than diabetes itself. Large vessel problems are far more frequent than microvascular disorders. Loss of arterial elasticity alters arterial flow patterns and increases microcirculatory peak flow rates. Hyperglycemia may directly disrupt elastin formation. Diabetic leg artery disease may be generated by nerve damage, reversing this interactive contribution sequence. The major anatomic feature of microangiopathy in long-term diabetes is an unevenly distributed thickening of the intima of smaller arterioles. The thickening is primarily due to accumulation of type IV (basement membrane) collagen. Arterioles change local vessel diameter to adjust blood distribution to meet current needs. The thickening compromises the maximum local blood flow that may be achieved by this means. Compromise of maximal arteriolar dilatation does not disrupt exercising muscle but in the kidney, retina, and possibly in nerve, local circumstances can generate serious damage. Each of these system's responses has unique features that mediate its vulnerability, but all these organs show arteriolar hyalinization. The increased arteriolar accumulation of type IV collagen appears to be a response to the tangential force generated by flow over local endothelial cells. An increase in peak arteriolar wall force is mediated by a diabetes-specific doubling of erythrocyte membrane curvature change resistance. Red cell aggregation rate determines the rate of damage. The same nonspecific burden may also predispose to heart disease and stroke. Intensive metabolic control improves red cell deformability and protects against arteriolar damage. Therapies that address the rheologic problem more directly may add to the effectiveness of good diabetes control in the future.

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Estimate of red-cell deformability and plasma viscosity based on flow curve

AIChE Journal ◽

10.1002/aic.690470123 ◽

2001 ◽

Vol 47 (1) ◽

pp. 230-239 ◽

Cited By ~ 4

Author(s):

S. Ookawara ◽

A. Yano ◽

K. Ogawa ◽

K. Taniguchi

Keyword(s):

Flow Curve ◽

Plasma Viscosity ◽

Red Cell ◽

Cell Deformability ◽

Red Cell Deformability

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Abnormal Blood Rheology in Young Male Diabetics with and without Retinopathy

10.1055/s-0039-1684520 ◽

1979 ◽

Author(s):

G.D.O. Lowe ◽

M.M. Drummond ◽

J.J.F. Belch ◽

J.M. Lowe ◽

A.C. MacCuish ◽

...

Keyword(s):

Blood Viscosity ◽

Smoking Habit ◽

Vascular Complications ◽

Young Male ◽

Blood Rheology ◽

Plasma Viscosity ◽

Red Cell ◽

Cell Deformability ◽

Rotational Viscometer ◽

Red Cell Deformability

We compared red cell deformability (filtration rate through 5 μ sieves), blood viscosity (rotational viscometer), haematocrit, plasma fibrinogen and plasma viscosity in young male diabetics (age <50 years) and normal controls matched for age and smoking habit. diabetics with no retinopathy or other vascular complications (n = 20) had normal red cell deformability, but increased blood viscosity at shear rates of 100s-1 (p<0.05) and is-1 (p<0. 01), due in part to moderate elevations of haematocrit, fibrinogen and plasma viscosity. Diabetics with retinopathy (n = 10) had a more marked increase in viscosity and also reduced red cell deformability (p<0.05). Increased blood viscosity is present prior to the onset of detectable vascular complications in male diabetics, while reduced red cell deformability is associated with complications.

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Blood Rheology in Post-Thrombotic Syndrome — A Pilot Study

Phlebology The Journal of Venous Disease ◽

10.1177/026835558800300309 ◽

1988 ◽

Vol 3 (3) ◽

pp. 181-183 ◽

Cited By ~ 6

Author(s):

E. Ernst ◽

A. Matrai ◽

E. Vinnemeier ◽

M. Marshall

Keyword(s):

Pilot Study ◽

Ex Vivo ◽

Blood Rheology ◽

Cell Aggregation ◽

Plasma Viscosity ◽

Red Cell ◽

Blood Fluidity ◽

Erythrocyte Sedimentation ◽

Disturbed Microcirculation ◽

Red Cell Aggregation

Patients suffering from post-thromobotic syndrome are compared to controls in terms of ex-vivo measurements to quantify the rheological behavior of blood: blood and plasma viscosity, haematocrit, red cell aggregation, red cell filterability, erythrocyte sedimentation rate (ESR), plasma fibrinogen. The results show that plasma viscosity, red cell filterability, ESR and fibrinogen are significantly changed indicating a lack of blood fluidity in post-thrombotic disease. It is suggested that the rheological deficit and the venous pathology both contribute to a disturbed microcirculation in the affected limb.

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Abnormal Blood Rheology in Young Male Diabetics With and Without Retinopathy

10.1055/s-0038-1665792 ◽

1979 ◽

Author(s):

G Lowe ◽

M Drummond ◽

J Belch ◽

J Lowe ◽

A MacCuish ◽

...

Keyword(s):

Blood Viscosity ◽

Smoking Habit ◽

Vascular Complications ◽

Young Male ◽

Blood Rheology ◽

Plasma Viscosity ◽

Red Cell ◽

Cell Deformability ◽

Rotational Viscometer ◽

Red Cell Deformability

We compared red cell deformability (filtration rate through 5 µ sieves), blood viscosity (rotational viscometer), haematocrit, plasma fibrinogen and plasma viscosity in young male diabetics (age ˂50 years) and normal controls matched for age and smoking habit. Diabetics with no retinopathy or other vascular complications (n = 20) had normal red cell deformability, but increased blood viscosity at shear rates of 100s-1(p ˂0. 05) and 1s-1(p ˂0. 01), due in part to moderate elevations of haematocrit, fibrinogen and plasma viscosity. Diabetics with retinopathy (n = 10) had a more marked increase in viscosity and also reduced red cell deformability (p ˂0. 05). Increased blood viscosity is present prior to the onset of detectable vascular complications in male diabetics, while reduced red cell deformability is associated with complications.

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NOVEL TECHIQUES FOR QUANTIFICATION OF RBC-SHAPE (RS) AND SHEAR INDUCED RBC ELONGATION (SIRE): APPLICATION FOR ANALYSIS OF DRUG INDUCED ALTERATIONS

10.1055/s-0038-1644217 ◽

1987 ◽

Author(s):

G Artmann ◽

R Grebe ◽

H Wolff ◽

R Degenhardt ◽

H Schmid-SchÖnbein

Keyword(s):

Membrane Curvature ◽

Low Flow ◽

Shear Stresses ◽

Red Cell ◽

Drug Induced ◽

Cell Deformability ◽

Red Cell Deformability ◽

Red Cell Membrane ◽

Filtration Method

In the past, red cell resting shape could only be assessed by subjective scaling, red cell deformability by a variety of rheological tests that are extremelydifficult to standardize and which all subject the RBC to high deforming forces. None of the latter have been accepted as reference in haematology, haemorheologyor pharmacology. A recent development from our group now allows objective, numerical analysis of red cell membrane curvature (i.e. the echinocytic or stomatocytic deviation from the discocytic resting shape) by a tangent count procedure in optical sections through freely suspended, randomly oriented RBC: (Grebe et al. Biorheology 22(6), 1985). Also, the deformation of point attached erythrocytes under the influence of extremely low shear stresses (0.05 Pa to 0.5 Pa, ARTOANN:Clin. Hemorheology 6, 1986), which are at least two orders of magnitude lower thanthat in any routinely available filtration method allows for the first time to model in vitro the extreme low flow states that occur in severe forms of haemodynamic insufficiency. These two methods in combination are ideally suited for routine tests of drug effects on normal human RBC: the drug action on RS can be monitored continuously during the action of drugs in the suspending medium; likewise, RISA can be recorded automatically on one population of adherent RBC while altering the composition and the drug concentration in the superfusate. The two methods were applied in combination to test rheological and membranological effects of two distinctly different compounds, namely Bencyclan (Bencylan-Hydrogen-Fumarate) and Vinpocitin (Aethyl vincamin) in normal cells and in cells after exposure to "stress conditions", i.e. hyperosmolarity and lactacidosis. Both olrugs given to n o r m a 1 RBC produce stomatocytosis in a done dependent fashion (1-100 uMolar). At shear stresses above o.6 Pa, the RISA is identical to controls, but is oxmsiderably less pronounced at lower shear stresses (T < 0.2 Pa). Thus, drugs of completely olifferent pharmacological action produce clear cut rheological effects on RBC in the micrcmolar concentration range; the combination of methods employed opens new possibilities for the systematic development of haemorheologically active drugs.Supported by DFG:Grant Gr 902/1-1

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An Assessment of Red Cell Deformability Using a Simple Filtration Method

10.1055/s-0038-1665788 ◽

1979 ◽

Author(s):

M Drummond ◽

G Lowe ◽

J Belch ◽

C Forbes ◽

J Barbenel

Keyword(s):

Cell Count ◽

Shear Viscosity ◽

White Cell Count ◽

White Cell ◽

Red Cell ◽

Cell Deformability ◽

Red Cell Deformability ◽

Simple Method ◽

Filtration Method ◽

Significant Difference

We investigated the reproducibility and validity of a simple method of measuring red cell deformability (filtration of whole blood through 5 µ sieves) and its relationship to haematocrit, blood viscosity, fibrinogen, white cell count, sex and smoking. The mean coefficient of variation in normals was 3. 7%. Tanned red cells showed marked loss of deformability. Blood filtration rate correlated with haematocrit (r = 0. 99 on dilution of samples, r = 0. 7 in 120 normals and patients). After correction for haematocrit, deformability correlated with high shear viscosity, but not low shear viscosity, fibrinogen or white cell count. In 60 normals there was no significant difference between males and females, or smokers and non-smokers, but in 11 smokers there was an acute fall in deformability after smoking 3 cigarettes (p<0. 05). Reduced deformability was found in acute myocardial infarction (n = 15, p<0. 01) and chronic peripheral arterial disease (n = 15, p<0. 01). The technique is reproducible, detects rigid cells and appears useful in the study of vascular disease.

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