scholarly journals Haemorheology in dilute, semi-dilute and dense suspensions of red blood cells

2019 ◽  
Vol 872 ◽  
pp. 818-848 ◽  
Author(s):  
Naoki Takeishi ◽  
Marco E. Rosti ◽  
Yohsuke Imai ◽  
Shigeo Wada ◽  
Luca Brandt

We present a numerical analysis of the rheology of a suspension of red blood cells (RBCs) in a wall-bounded shear flow. The flow is assumed as almost inertialess. The suspension of RBCs, modelled as biconcave capsules whose membrane follows the Skalak constitutive law, is simulated for a wide range of viscosity ratios between the cytoplasm and plasma,$\unicode[STIX]{x1D706}=0.1$–10, for volume fractions up to$\unicode[STIX]{x1D719}=0.41$and for different capillary numbers ($Ca$). Our numerical results show that an RBC at low$Ca$tends to orient to the shear plane and exhibits so-called rolling motion, a stable mode with higher intrinsic viscosity than the so-called tumbling motion. As$Ca$increases, the mode shifts from the rolling to the swinging motion. Hydrodynamic interactions (higher volume fraction) also allow RBCs to exhibit tumbling or swinging motions resulting in a drop of the intrinsic viscosity for dilute and semi-dilute suspensions. Because of this mode change, conventional ways of modelling the relative viscosity as a polynomial function of$\unicode[STIX]{x1D719}$cannot be simply applied in suspensions of RBCs at low volume fractions. The relative viscosity for high volume fractions, however, can be well described as a function of an effective volume fraction, defined by the volume of spheres of radius equal to the semi-middle axis of a deformed RBC. We find that the relative viscosity successfully collapses on a single nonlinear curve independently of$\unicode[STIX]{x1D706}$except for the case with$Ca\geqslant 0.4$, where the fit works only in the case of low/moderate volume fraction, and fails in the case of a fully dense suspension.

2021 ◽  
pp. 1-10
Author(s):  
Rui Zhong ◽  
Dingding Han ◽  
Xiaodong Wu ◽  
Hong Wang ◽  
Wanjing Li ◽  
...  

Background: The hypoxic environment stimulates the human body to increase the levels of hemoglobin (HGB) and hematocrit and the number of red blood cells. Such enhancements have individual differences, leading to a wide range of HGB in Tibetans’ whole blood (WB). Study Design: WB of male Tibetans was divided into 3 groups according to different HGB (i.e., A: >120 but ≤185 g/L, B: >185 but ≤210 g/L, and C: >210 g/L). Suspended red blood cells (SRBC) processed by collected WB and stored in standard conditions were examined aseptically on days 1, 14, 21, and 35 after storage. The routine biochemical indexes, deformability, cell morphology, and membrane proteins were tested. Results: Mean corpuscular volume, adenosine triphosphate, pH, and deformability were not different in group A vs. those in storage (p > 0.05). The increased rate of irreversible morphology of red blood cells was different among the 3 groups, but there was no difference in the percentage of red blood cells with an irreversible morphology after 35 days of storage. Group C performed better in terms of osmotic fragility and showed a lower rigid index than group A. Furthermore, SDS-PAGE revealed similar cross-linking degrees of cell membrane protein but the band 3 protein of group C seemed to experience weaker clustering than that of group A as detected by Western Blot analysis after 35 days of storage. Conclusions: There was no difference in deformability or morphological changes in the 3 groups over the 35 days of storage. High HGB levels of plateau SRBC did not accelerate the RBC change from a biconcave disc into a spherical shape and it did not cause a reduction in deformability during 35 days of preservation in bank conditions.


Author(s):  
Peter W. Windes ◽  
Danesh K. Tafti ◽  
Bahareh Behkam

The present work lays out an accurate, three-dimensional computational fluid dynamics (CFD) model of a human blood capillary. This model is composed of red blood cells and blood plasma inside a cylindrical section of a capillary. The plasma flow is resolved using an incompressible Navier-Stokes solver. At the level of capillaries, red blood cells must be individually handled to correctly resolve the hydrodynamics in the system. They cannot be lumped in with the plasma and considered as a non-Newtonian suspension because of the relative scale of the capillaries and the blood cells. Red blood cells act as highly deformable, fluid filled vesicles which readily deform from their typical biconcave shape when passing through narrow capillaries. In the present model, the deformed shape of red blood cells is predicted using a combination of analytical models and experimental data on cell deformation. The cell volume, cell surface area, and plasma layer thickness are found to be the key parameters which define red blood cell deformation in capillaries. The red blood cells are imposed in the flow using the immersed boundary method (IBM). To save computational resources while still yielding an accurate model, the deformed shape of each red blood cell is calculated once prior to running the simulation and then held constant throughout the run. In order to validate the model, two parameters — apparent relative viscosity and hematocrit ratio — were examined. The present model shows good comparison to experimental values for both these parameters.


Author(s):  
Orest Shardt ◽  
Jos Derksen

We describe the direct simulation of high-solids-fraction suspensions of non-spherical rigid particles that are slightly denser than the fluid. The lattice-Boltzmann method is used to solve the flow of the interstitial Newtonian fluid, and the immersed boundary method is used to enforce a no-slip boundary condition at the surface of each particle. The surface points for the immersed boundary method are also employed for collision handling by applying repulsive forces between nearby surface points. Due to the finite number of these points, the method simulates rough surface collisions. We also discuss methods for integrating the equations of particle motion at low density ratios and propose a method with improved accuracy. Rigid particles shaped like red blood cells were simulated. Simulations of a single particle showed that the particle settles in its original orientation when the Reynolds number is low (1.2) but flips to a higher drag orientation when the Reynolds number is higher (7.3). A simulation with a 45% solids volume fraction and a low solid over fluid density ratio showed the possibility of simulating blood as it is found in the body. A simulation at a lower solids volume fraction (35%) was used to compare the results with the erythrocyte sedimentation rate (ESR), a common blood test. The sedimentation rate was estimated as 0.2 mm/hr, which is an order of magnitude lower than a typical ESR of about 6 mm/hr for a healthy adult. The most likely reasons for the discrepancy are the omission of agglomeration-inducing inter-cellular forces from the simulations and the treatment of the red blood cells as rigid particles.


2009 ◽  
Vol 101 (03) ◽  
pp. 439-451 ◽  
Author(s):  
Laurent Burnier ◽  
Pierre Fontana ◽  
Brenda R. Kwak ◽  
Anne Angelillo-Scherrer

SummaryConsiderable interest for cell-derived microparticles has emerged, pointing out their essential role in haemostatic response and their potential as disease markers, but also their implication in a wide range of physiological and pathological processes. They derive from different cell types including platelets – the main source of microparticles – but also from red blood cells, leukocytes and endothelial cells, and they circulate in blood. Despite difficulties encountered in analyzing them and disparities of results obtained with a wide range of methods, microparticle generation processes are now better understood. However, a generally admitted definition of microparticles is currently lacking. For all these reasons we decided to review the literature regarding microparticles in their widest definition, including ectosomes and exosomes, and to focus mainly on their role in haemostasis and vascular medicine.


1994 ◽  
Vol 116 (1) ◽  
pp. 79-88 ◽  
Author(s):  
G. Enden ◽  
A. S. Popel

Owing in part to a plasma-skimming mechanism, the distribution of red blood cells (RBCs) into branches of microvascular bifurcations typically differs from the distribution of the bulk blood flow. This paper analyzes the plasma-skimming mechanism that causes phase separation due to uneven distribution of red blood cells at the inlet cross section of the parent vessel. In a previous study, the shape of the surface that divides the flow into the branches was found by numerical simulation of three-dimensional flow of a homogeneous Newtonian fluid in T-type bifurcations. Those findings are used in this study to determine, as a first approximation, the side-to-parent vessel RBC flux ratio and discharge hematocrit ratio as a function of corresponding flow ratios. Calculations are based on the assumption that RBCs move along streamlines of a homogeneous Newtonian fluid and are uniformly distributed within a concentric core at the inlet cross section of the parent vessel. The results of our calculations agree well for a wide range of flow parameters with experimental data from in vivo and in vitro studies.


Soft Matter ◽  
2014 ◽  
Vol 10 (24) ◽  
pp. 4258-4267 ◽  
Author(s):  
Dmitry A. Fedosov ◽  
Matti Peltomäki ◽  
Gerhard Gompper

The behavior of red blood cells (RBCs) in microvessels plays an important role in blood flow resistance and in the cell partitioning within a microcirculatory network. We employ mesoscopic hydrodynamic simulations to study the behavior and deformation of single RBCs in microchannels yielding the construction of diagrams of RBC shapes for a wide range of flow conditions.


2022 ◽  
Vol 12 ◽  
Author(s):  
Scott Atwell ◽  
Catherine Badens ◽  
Anne Charrier ◽  
Emmanuèle Helfer ◽  
Annie Viallat

In this work, we compared the dynamics of motion in a linear shear flow of individual red blood cells (RBCs) from healthy and pathological donors (Sickle Cell Disease (SCD) or Sickle Cell-β-thalassemia) and of low and high densities, in a suspending medium of higher viscosity. In these conditions, at lower shear rates, biconcave discocyte-shaped RBCs present an unsteady flip-flopping motion, where the cell axis of symmetry rotates in the shear plane, rocking to and fro between an orbital angle ±ϕ observed when the cell is on its edge. We show that the evolution of ϕ depends solely on RBC density for healthy RBCs, with denser RBCs displaying lower ϕ values than the lighter ones. Typically, at a shear stress of 0.08 Pa, ϕ has values of 82 and 72° for RBCs with average densities of 1.097 and 1.115, respectively. Surprisingly, we show that SCD RBCs display the same ϕ-evolution as healthy RBCs of same density, showing that the flip-flopping behavior is unaffected by the SCD pathology. When the shear stress is increased further (above 0.1 Pa), healthy RBCs start going through a transition to a fluid-like motion, called tank-treading, where the RBC has a quasi-constant orientation relatively to the flow and the membrane rotates around the center of mass of the cell. This transition occurs at higher shear stresses (above 0.2 Pa) for denser cells. This shift toward higher stresses is even more remarkable in the case of SCD RBCs, showing that the transition to the tank-treading regime is highly dependent on the SCD pathology. Indeed, at a shear stress of 0.2 Pa, for RBCs with a density of 1.097, 100% of healthy RBCs have transited to the tank-treading regime vs. less than 50% SCD RBCs. We correlate the observed differences in dynamics to the alterations of RBC mechanical properties with regard to density and SCD pathology reported in the literature. Our results suggest that it might be possible to develop simple non-invasive assays for diagnosis purpose based on the RBC motion in shear flow and relying on this millifluidic approach.


2019 ◽  
Author(s):  
Amir Saadat ◽  
Christopher J. Guido ◽  
Eric S. G. Shaqfeh

The dynamics of red blood cells in small arterioles are important as these dynamics affect many physiological processes such as hemostasis and thrombosis. However, studying red blood cell flows via computer simulations is challenging due to the complex shapes and the non-trivial viscosity contrast of a red blood cell. To date, little progress has been made studying small arteriole flows (20-40μm) with a hematocrit (red blood cell volume fraction) of 10-20% and a physiological viscosity contrast. In this work, we present the results of large-scale simulations that show how the channel size, viscosity contrast of the red blood cells, and hematocrit affect cell distributions and the cell-free layer in these systems. We utilize a massively-parallel immersed boundary code coupled to a finite volume solver to capture the particle resolved physics. We show that channel size qualitatively changes how the cells distribute in the channel. Our results also indicate that at a hematocrit of 10% that the viscosity contrast is not negligible when calculating the cell free layer thickness. We explain this result by comparing lift and collision trajectories of cells at different viscosity contrasts.


2017 ◽  
Vol 16 (1) ◽  
Author(s):  
Muneaki Hashimoto ◽  
Shouki Yatsushiro ◽  
Shohei Yamamura ◽  
Masato Tanaka ◽  
Hirokazu Sakamoto ◽  
...  

2019 ◽  
Vol 2019 ◽  
pp. 1-12 ◽  
Author(s):  
Victor V. Revin ◽  
Natalia V. Gromova ◽  
Elvira S. Revina ◽  
Anastasia Yu. Samonova ◽  
Alexander Yu. Tychkov ◽  
...  

Using a wide range of different physical and chemical methods, it was found that the oxidative stress caused by addition of hydrogen peroxide to the incubation medium has a significant effect on the conformation of haematoporphyrin, influencing the oxygen-binding properties of haemoglobin in red blood cells. Morphofunctional characteristics of red blood cells change; in particular, we have observed the transformation of erythrocytes, their transition into echinocytes. In erythrocytes, in response to increased lipid peroxidation (LPO) antioxidant enzymes become active. The use of natural antioxidants (β-carotene and resveratrol) works towards reducting the level of oxidative processes. Resveratrol has the greatest antioxidant effect.


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