Red Cell Deformability and Capillary Blood Flow

1971 ◽  
Vol 51 (4) ◽  
pp. 679-701 ◽  
Author(s):  
D. Braasch
Keyword(s):  
Blood Flow ◽  
Capillary Blood ◽  
Capillary Blood Flow ◽  
Red Cell ◽  
Cell Deformability ◽  
Red Cell Deformability

Abnormal Red Cell Deformability and Aggregation in Sickle Cell Trait

Blood ◽  
2012 ◽  
Vol 120 (21) ◽  
pp. 1001-1001
Author(s):  
Jon Detterich ◽  
Adam M Bush ◽  
Roberta Miyeko Kato ◽  
Rose Wenby ◽  
Thomas D. Coates ◽  
...  
Keyword(s):  
Blood Flow ◽  
Blood Viscosity ◽  
Whole Blood ◽  
Red Cell ◽  
Cell Deformability ◽  
Autologous Plasma ◽  
Red Cell Deformability ◽  
Whole Blood Viscosity ◽  
Rbc Aggregation ◽  
Rbc Deformability

Abstract Abstract 1001 Introduction: SCT occurs in 8% of African Americans and is not commonly associated with clinical disease. Nonetheless, the United States Armed Forces has reported that SCT conveys a 30-fold risk of sudden cardiac arrest and a 200-fold risk from exertional rhabdomyolysis. In fact, rhabdomyolysis in athletes with SCT has been the principal cause of death in NCAA football players in the last decade, leading to recently mandated SCT testing in all Division-1 players. In SCT, RBC sickle only under extreme conditions and with slow kinetics. Therefore, rhabdomyolysis most likely occurs in SCT when a “perfect storm” of factors converges to critically imbalance oxygen supply and demand in muscles. We hypothesize that in SCT subjects, abnormal RBC rheology, particularly aggregation and deformability, play an important role in abnormal muscle blood flow supply and distribution to exercising muscle. To test this hypothesis, we examined whole blood viscosity, RBC aggregation, and RBC deformability in 11 SCT and 10 control subjects prior to and following maximum handgrip exercise. Methods: Maximum voluntary contraction (MVC) was assessed by handgrip dynamometer in the dominant arm. Baseline blood was collected for CBC, whole blood viscosity, RBC aggregation, and RBC deformability. Patients then maintained 60% MVC exercise until exhaustion. Following 8 minutes of recovery, a venous blood gas and blood for repeat viscosity assessments was collected from the antecubital fossa of the exercising limb. Whole blood viscosity over a shear rate range of 1–1, 000 1/s was determined by an automated tube viscometer, RBC deformability from 0.5–50 Pa via laser ektacytometry (LORCA) and RBC aggregation in both autologous plasma and 3% dextran 70 kDa using an automated cone-place aggregometer (Myrenne). Aggregation measurements included extent at stasis (M), strength of aggregation (GT min) and kinetics (T ½). Results: Baseline CBC and aggregation values are summarized in Table 1. Both static RBC aggregation in plasma and RBC aggregation in dextran (aggregability) were significantly increased in SCT (Table 1). The rate of aggregation formation trended higher in SCT but the strength of aggregation was not different between the two groups. In SCT subjects, red cell deformability was impaired at low shear stress but greater than controls at higher shear stress (Figure 1). Red cell deformability was completely independent of oxygenation status states in both SCT and control subjects. Whole blood viscosity did not different between the two groups whether oxygenated or deoxygenated and prior to or following handgrip exercise. Discussion: Three important hemorheological differences were observed for SCT subjects versus controls: a) RBC deformability was below control at low stress levels yet greater than control at higher stress; b) The extent of RBC aggregation in autologous plasma was about 40% greater; c) The extent of RBC aggregation for washed RBC re-suspended in an aggregating medium (i.e., 3% dextran 70 kDa) was about 30% higher. RBC deformability is a major determinant of in vivo blood flow dynamics, especially in the microcirculation; decreased deformability adversely affects tissue perfusion. RBC aggregation is also an important determinant since it affects both resistance to blood flow and RBC distribution in a vascular bed (e.g., plasma skimming). The finding of greater aggregability (i.e., higher aggregation in the defined dextran medium) indicates that RBC in SCT have an altered membrane surface in which the penetration of this polymer into the glycocalyx is abnormal. The combined effects of these three rheological parameters is likely to impair in vivo blood flow in SCT, perhaps to a degree resulting in pathophysiological changes of the cardiovascular system. Disclosures: Coates: Novartis: Speakers Bureau; Apopharma: Consultancy. Wood:Ferrokin Biosciences: Consultancy; Shire: Consultancy; Apotex: Consultancy, Honoraria; Novartis: Honoraria, Research Funding.

The effect of increasing temperature on skin blood flow and red cell deformability

1993 ◽  
Vol 13 (3) ◽  
pp. 235-245 ◽  
Author(s):  
M. S. Rendell ◽  
S. T. Kelly ◽  
O. Bamisedun ◽  
T. Luu ◽  
D. A. Finney ◽  
...  
Keyword(s):  
Blood Flow ◽  
Skin Blood Flow ◽  
Red Cell ◽  
Cell Deformability ◽  
Red Cell Deformability ◽  
Increasing Temperature

Lutein Complex Supplementation Increases Ocular Blood Flow Biomarkers in Healthy Subjects

2019 ◽  
Vol 89 (1-2) ◽  
pp. 5-12
Author(s):  
Alon Harris ◽  
Brent Siesky ◽  
Amelia Huang ◽  
Thai Do ◽  
Sunu Mathew ◽  
...  
Keyword(s):  
Blood Pressure ◽  
Blood Flow ◽  
Diastolic Blood Pressure ◽  
Healthy Subjects ◽  
Ocular Blood Flow ◽  
Capillary Blood ◽  
Post Treatment ◽  
Capillary Blood Flow ◽  
Doppler Imaging ◽  
Retinal Capillary

Abstract. Introduction: To investigate the effects of a lutein complex supplementation on ocular blood flow in healthy subjects. Materials and Methods: Sixteen healthy female patients (mean age 36.8 ± 12.1 years) were enrolled in this randomized, placebo-controlled, double-blinded, two-period crossover study. Subjects received daily an oral dose of the lutein with synergistic phytochemicals complex (lutein (10 mg), ascorbic acid (500 mg), tocopherols (364 mg), carnosic acid (2.5 mg), zeaxanthin (2 mg), copper (2 mg), with synergistic effects in reducing pro-inflammatory mediators and cytokines when administered together in combination) and placebo during administration periods. Measurements were taken before and after three-week supplementation periods, with crossover visits separated by a three-week washout period. Data analysis included blood pressure, heart rate, intraocular pressure, visual acuity, contrast sensitivity detection, ocular perfusion pressure, confocal scanning laser Doppler imaging of retinal capillary blood flow, and Doppler imaging of the retrobulbar blood vessels. Results: Lutein complex supplementation produced a statistically significant increase in mean superior retinal capillary blood flow, measured in arbitrary units (60, p = 0.0466) and a decrease in the percentage of avascular area in the superior (−0.029, p = 0.0491) and inferior (−0.023, p = 0.0477) retina, as well as reduced systolic (−4.06, p = 0.0295) and diastolic (−3.69, p = 0.0441) blood pressure measured in mmHg from baseline. Data comparison between the two supplement groups revealed a significant decrease in systemic diastolic blood pressure (change from pre- to post-treatment with lutein supplement (mean (SE)): −3.69 (1.68); change from pre- to post-treatment with placebo: 0.31 (2.57); p = 0.0357) and a significant increase in the peak systolic velocity (measured in cm/sec) in the central retinal artery (change from pre- to post-treatment with lutein supplement: 0.36 (0.19); change from pre- to post-treatment with placebo: −0.33 (0.21); p = 0.0384) with lutein complex supplement; data analyses from the placebo group were all non-significant. Discussion: In healthy participants, oral administration of a lutein phytochemicals complex for three weeks produced increased ocular blood flow biomarkers within retinal vascular beds and reduced diastolic blood pressure compared to placebo.

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

1984 ◽  
Vol 51 (01) ◽  
pp. 006-008 ◽  
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.

An Assessment of Red Cell Deformability Using a Simple Filtration Method

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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