The pliant and ag(g)reeable erythrocyte

Hardeman, Max R.

doi:10.3233/ch-131684

Cited by 3 publications

(2 citation statements)

References 9 publications

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“…Indeed, every RBC needs to pass several times a day through narrow capillaries, without rupture, to release oxygen to the tissues. To accomplish this, RBCs need to dynamically adapt their shapes to the hemodynamic and vascular geometry conditions 1,2 . The deformability of a RBC is mainly influenced by three factors: (1) the surface-area-to-volume ratio (S/V; i.e., cell sphericity), (2) the internal viscosity, which is mainly dependent on the mean cell hemoglobin concentration (MCHC) and (3) the rheological properties of the membrane 3 .…”

Section: Introductionmentioning

confidence: 99%

Impact of surface-area-to-volume ratio, internal viscosity and membrane viscoelasticity on red blood cell deformability measured in isotonic condition

Renoux

Faivre

Bessaa

et al. 2019

Sci Rep

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Osmotic gradient ektacytometry is the gold standard to assess red blood cell (RBC) deformability. It has been proposed that, when measured in isotonic condition, RBC deformability at low shear stress would depend on membrane elasticity while it would be influenced by internal viscosity when measured at high shear stress, but this hypothesis needs to be further addressed. Healthy RBCs were rigidified by treatment with lysolecithine (LPC), diamide or nystatine associated with hyperosmolar solutions (OSMO), which reduces membrane surface area, decreases membrane elasticity or promotes cell dehydration, respectively. Diamide treatment resulted in a decrease in isotonic RBC deformability at all shear stresses tested (i.e. from 0.3 to 30 Pa). LPC and OSMO treatments caused a decrease in isotonic RBC deformability above 3 Pa only. Isotonic RBC deformability from patients with hereditary spherocytosis or sickle cell disease was mainly decreased above 1.69 Pa. Our findings indicate that decreased isotonic RBC deformability at shear stresses above 3 Pa would be related to a reduction in the surface-area-to-volume ratio and/or to a loss of membrane elasticity and/or to an increase in internal viscosity while a decrease of RBC deformability below 3 Pa would reflect a loss of membrane elasticity.

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Section: Introductionmentioning

confidence: 99%

Impact of surface-area-to-volume ratio, internal viscosity and membrane viscoelasticity on red blood cell deformability measured in isotonic condition

Renoux

Faivre

Bessaa

et al. 2019

Sci Rep

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“…This review demonstrates that erythrocyte deformability and whole-blood viscosity are inextricably linked. A failure of the erythrocyte to assume the proper degree of deformability could lead to hyperviscosity and thus hypertension [27]. Several reports have documented decreased erythrocyte deformability in association with hypertension (reviewed in reference [28]).…”

Section: Diurnal Variation In Blood Volumementioning

confidence: 99%

Hormonal Control of Blood Viscosity

Sloop,

Pop,

Weidman

et al. 2024

Cureus

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The hemodynamic milieu differs throughout the vascular tree because of varying vascular geometry and blood velocities. Accordingly, the risk of turbulence, which is dictated by the Reynolds and Dean numbers, also varies. Relatively high blood viscosity is needed to prevent turbulence in the left ventricle and aorta, where high-velocity blood changes direction several times. Low blood viscosity is needed in the capillaries, where erythrocytes pass through vessels with a diameter smaller than their own. In addition, higher blood viscosity is necessary when the cardiac output and peak blood velocity increase as a part of a sympathetic response or anemia, which occurs following significant hemorrhage. Blood viscosity, as reflected in systemic vascular resistance and vascular wall shear stress, is sensed, respectively, by cardiomyocyte stretching in the left ventricle and mechanoreceptors for wall shear stress in the carotid sinus. By controlling blood volume and red blood cell mass, the renin-aldosterone-angiotensin system and the systemic vascular resistance response control the hematocrit, the strongest intrinsic determinant of blood viscosity. These responses provide gross control of blood viscosity. Fine-tuning of blood viscosity in transient conditions is provided by hormonal control of erythrocyte deformability. The short half-life of some of these hormones limits their activity to specific vascular beds. Hormones that modulate blood viscosity include erythropoietin, angiotensin II, brain natriuretic factor, epinephrine, prostacyclin E2, antidiuretic hormone, and nitric oxide.

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Actual vs optimal fetal hematocrit measured with punctures of cord blood in utero: Relationship with umbilical artery resistance

Brun

Boulot

Varlet‐Marie

2017

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Physiological studies on fetal blood in narrow glass tubes have suggested that fetal optimal hematocrit (hct) might be as high as 60%. A theoretical 'ideal' hct can also be predicted with a theoretical curve of hematocrit/viscosity (h/η) ratio vs hct constructed with Quemada's model. We used the database of one of our previous papers on fetal hemorheology to reinterpret its results with this concept. A series of 28 intrauterine cord punctures (between 19 and 33 weeks gestation) with doppler measurements of resistance in umbilical arteries was studied. The theoretical 'optimal hematocrit' was well correlated to actual (r = 0.857, p < 0.01) but systematically lower (Bland-Altman plot +12.1[8.52-15.7]) than the actual one. Umbilical artery resistance index is correlated with actual hematocrit (r = 0.407, p < 0.05), the discrepancy between ideal and actual (r = - 0.542, p < 0.05) but not predicted ideal hematocrit, suggesting that the discrepancy between ideal and actual may reflect an adaptative decrease aiming at reducing vascular resistance. These findings indicate that prediction of ideal hematocrit with Quemada's equation makes sense in fetal blood, and suggest that a 'viscoregulatory mechanism' maintains hematocrit below this theoretical value in order to avoid excess vascular resistance.

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The pliant and ag(g)reeable erythrocyte

Cited by 3 publications

References 9 publications

Impact of surface-area-to-volume ratio, internal viscosity and membrane viscoelasticity on red blood cell deformability measured in isotonic condition

Impact of surface-area-to-volume ratio, internal viscosity and membrane viscoelasticity on red blood cell deformability measured in isotonic condition

Hormonal Control of Blood Viscosity

Actual vs optimal fetal hematocrit measured with punctures of cord blood in utero: Relationship with umbilical artery resistance

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