1
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Li G, Qiang Y, Li H, Li X, Buffet PA, Dao M, Karniadakis GE. A combined computational and experimental investigation of the filtration function of splenic macrophages in sickle cell disease. PLoS Comput Biol 2023; 19:e1011223. [PMID: 38091361 PMCID: PMC10752522 DOI: 10.1371/journal.pcbi.1011223] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/30/2023] [Revised: 12/27/2023] [Accepted: 11/03/2023] [Indexed: 12/26/2023] Open
Abstract
Being the largest lymphatic organ in the body, the spleen also constantly controls the quality of red blood cells (RBCs) in circulation through its two major filtration components, namely interendothelial slits (IES) and red pulp macrophages. In contrast to the extensive studies in understanding the filtration function of IES, fewer works investigate how the splenic macrophages retain the aged and diseased RBCs, i.e., RBCs in sickle cell disease (SCD). Herein, we perform a computational study informed by companion experiments to quantify the dynamics of RBCs captured and retained by the macrophages. We first calibrate the parameters in the computational model based on microfluidic experimental measurements for sickle RBCs under normoxia and hypoxia, as those parameters are not available in the literature. Next, we quantify the impact of key factors expected to dictate the RBC retention by the macrophages in the spleen, namely, blood flow conditions, RBC aggregation, hematocrit, RBC morphology, and oxygen levels. Our simulation results show that hypoxic conditions could enhance the adhesion between the sickle RBCs and macrophages. This, in turn, increases the retention of RBCs by as much as four-fold, which could be a possible cause of RBC congestion in the spleen of patients with SCD. Our study on the impact of RBC aggregation illustrates a 'clustering effect', where multiple RBCs in one aggregate can make contact and adhere to the macrophages, leading to a higher retention rate than that resulting from RBC-macrophage pair interactions. Our simulations of sickle RBCs flowing past macrophages for a range of blood flow velocities indicate that the increased blood velocity could quickly attenuate the function of the red pulp macrophages on detaining aged or diseased RBCs, thereby providing a possible rationale for the slow blood flow in the open circulation of the spleen. Furthermore, we quantify the impact of RBC morphology on their tendency to be retained by the macrophages. We find that the sickle and granular-shaped RBCs are more likely to be filtered by macrophages in the spleen. This finding is consistent with the observation of low percentages of these two forms of sickle RBCs in the blood smear of SCD patients. Taken together, our experimental and simulation results aid in our quantitative understanding of the function of splenic macrophages in retaining the diseased RBCs and provide an opportunity to combine such knowledge with the current knowledge of the interaction between IES and traversing RBCs to apprehend the complete filtration function of the spleen in SCD.
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Affiliation(s)
- Guansheng Li
- Division of Applied Mathematics, Brown University, Providence, Rhode Island, United States of America
| | - Yuhao Qiang
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - He Li
- School of Chemical, Materials and Biomedical Engineering, University of Georgia, Athens, Georgia, United States of America
| | - Xuejin Li
- Department of Engineering Mechanics and Center for X-Mechanics, Zhejiang University, Hangzhou, Zhejiang, China
| | - Pierre A. Buffet
- Université Paris Cité and Université des Antilles, Inserm, Biologie Intégrée du Globule Rouge, Paris, France
| | - Ming Dao
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, United States of America
| | - George Em Karniadakis
- Division of Applied Mathematics, Brown University, Providence, Rhode Island, United States of America
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2
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Hyakutake T, Tsutsumi Y, Miyoshi Y, Yasui M, Mizuno T, Tateno M. Red Blood Cell Partitioning Using a Microfluidic Channel with Ladder Structure. MICROMACHINES 2023; 14:1421. [PMID: 37512732 PMCID: PMC10385109 DOI: 10.3390/mi14071421] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/23/2023] [Revised: 07/12/2023] [Accepted: 07/13/2023] [Indexed: 07/30/2023]
Abstract
This study investigated the partitioning characteristics of red blood cells (RBCs) within capillaries, with a specific focus on ladder structures observed near the end of the capillaries. In vitro experiments were conducted using microfluidic channels with a ladder structure model comprising six bifurcating channels that exhibited an anti-parallel flow configuration. The effects of various factors, such as the parent channel width, distance between branches, and hematocrit, on RBC partitioning in bifurcating channels were evaluated. A decrease in the parent channel width resulted in an increase in the heterogeneity in the hematocrit distribution and a bias in the fractional RBC flux. Additionally, variations in the distance between branches affected the RBC distribution, with smaller distances resulting in greater heterogeneity. The bias of the RBC distribution in the microchannel cross section had a major effect on the RBC partitioning characteristics. The influence of hematocrit variations on the RBC distribution was also investigated, with lower hematocrit values leading to a more pronounced bias in the RBC distribution. Overall, this study provides valuable insights into RBC distribution characteristics in capillary networks, contributing to our understanding of the physiological mechanisms of RBC phase separation in the microcirculatory system. These findings have implications for predicting oxygen heterogeneity in tissues and could aid in the study of diseases associated with impaired microcirculation.
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Affiliation(s)
- Toru Hyakutake
- Faculty of Engineering, Yokohama National University, 79-5 Hodogaya, Yokohama 240-8501, Japan
| | - Yuya Tsutsumi
- Graduate School of Engineering Science, Yokohama National University, 79-5 Hodogaya, Yokohama 240-8501, Japan
| | - Yohei Miyoshi
- Graduate School of Engineering Science, Yokohama National University, 79-5 Hodogaya, Yokohama 240-8501, Japan
| | - Manabu Yasui
- Kanagawa Institute of Industrial Science and Technology, 705-1 Shimoimaizumi, Ebina 243-0435, Japan
| | - Tomoki Mizuno
- Graduate School of Engineering Science, Yokohama National University, 79-5 Hodogaya, Yokohama 240-8501, Japan
| | - Mizuki Tateno
- College of Engineering Science, Yokohama National University, 79-5 Hodogaya, Yokohama 240-8501, Japan
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3
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Li G, Qiang Y, Li H, Li X, Dao M, Karniadakis GE. In silico and in vitro study of the adhesion dynamics of erythrophagocytosis in sickle cell disease. Biophys J 2023; 122:2590-2604. [PMID: 37231647 PMCID: PMC10323029 DOI: 10.1016/j.bpj.2023.05.022] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/30/2022] [Revised: 04/12/2023] [Accepted: 05/18/2023] [Indexed: 05/27/2023] Open
Abstract
Erythrophagocytosis occurring in the spleen is a critical process for removing senescent and diseased red blood cells (RBCs) from the microcirculation. Although some progress has been made in understanding how the biological signaling pathways mediate the phagocytic processes, the role of the biophysical interaction between RBCs and macrophages, particularly under pathological conditions such as sickle cell disease, has not been adequately studied. Here, we combine computational simulations with microfluidic experiments to quantify RBC-macrophage adhesion dynamics under flow conditions comparable to those in the red pulp of the spleen. We also investigate the RBC-macrophage interaction under normoxic and hypoxic conditions. First, we calibrate key model parameters in the adhesion model using microfluidic experiments for normal and sickle RBCs under normoxia and hypoxia. We then study the adhesion dynamics between the RBC and the macrophage. Our simulation illustrates three typical adhesion states, each characterized by a distinct dynamic motion of the RBCs, namely firm adhesion, flipping adhesion, and no adhesion (either due to no contact with macrophages or detachment from the macrophages). We also track the number of bonds formed when RBCs and macrophages are in contact, as well as the contact area between the two interacting cells, providing mechanistic explanations for the three adhesion states observed in the simulations and microfluidic experiments. Furthermore, we quantify, for the first time to our knowledge, the adhesive forces between RBCs (normal and sickle) and macrophages under different oxygenated conditions. Our results show that the adhesive forces between normal cells and macrophages under normoxia are in the range of 33-58 pN and 53-92 pN for sickle cells under normoxia and 155-170 pN for sickle cells under hypoxia. Taken together, our microfluidic and simulation results improve our understanding of the biophysical interaction between RBCs and macrophages in sickle cell disease and provide a solid foundation for investigating the filtration function of the splenic macrophages under physiological and pathological conditions.
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Affiliation(s)
- Guansheng Li
- Division of Applied Mathematics, Brown University, Providence, Rhode Island
| | - Yuhao Qiang
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts
| | - He Li
- School of Chemical, Materials and Biomedical Engineering, University of Georgia, Athens, Georgia.
| | - Xuejin Li
- Department of Engineering Mechanics and Center for X-Mechanics, Zhejiang University, Hangzhou, China
| | - Ming Dao
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts.
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4
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Li G, Qiang Y, Li H, Li X, Buffet PA, Dao M, Karniadakis GE. A combined computational and experimental investigation of the filtration function of splenic macrophages in sickle cell disease. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.05.31.543007. [PMID: 37398427 PMCID: PMC10312537 DOI: 10.1101/2023.05.31.543007] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 07/04/2023]
Abstract
Being the largest lymphatic organ in the body, the spleen also constantly controls the quality of red blood cells (RBCs) in circulation through its two major filtration components, namely interendothelial slits (IES) and red pulp macrophages. In contrast to the extensive studies in understanding the filtration function of IES, there are relatively fewer works on investigating how the splenic macrophages retain the aged and diseased RBCs, i.e., RBCs in sickle cell disease (SCD). Herein, we perform a computational study informed by companion experiments to quantify the dynamics of RBCs captured and retained by the macrophages. We first calibrate the parameters in the computational model based on microfluidic experimental measurements for sickle RBCs under normoxia and hypoxia, as those parameters are not available in the literature. Next, we quantify the impact of a set of key factors that are expected to dictate the RBC retention by the macrophages in the spleen, namely, blood flow conditions, RBC aggregation, hematocrit, RBC morphology, and oxygen levels. Our simulation results show that hypoxic conditions could enhance the adhesion between the sickle RBCs and macrophages. This, in turn, increases the retention of RBCs by as much as five-fold, which could be a possible cause of RBC congestion in the spleen of patients with SCD. Our study on the impact of RBC aggregation illustrates a 'clustering effect', where multiple RBCs in one aggregate can make contact and adhere to the macrophages, leading to a higher retention rate than that resulting from RBC-macrophage pair interactions. Our simulations of sickle RBCs flowing past macrophages for a range of blood flow velocities indicate that the increased blood velocity could quickly attenuate the function of the red pulp macrophages on detaining aged or diseased RBCs, thereby providing a possible rationale for the slow blood flow in the open circulation of the spleen. Furthermore, we quantify the impact of RBC morphology on their tendency to be retained by the macrophages. We find that the sickle and granular-shaped RBCs are more likely to be filtered by macrophages in the spleen. This finding is consistent with the observation of low percentages of these two forms of sickle RBCs in the blood smear of SCD patients. Taken together, our experimental and simulation results aid in our quantitative understanding of the function of splenic macrophages in retaining the diseased RBCs and provide an opportunity to combine such knowledge with the current knowledge of the interaction between IES and traversing RBCs to apprehend the complete filtration function of the spleen in SCD.
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Affiliation(s)
- Guansheng Li
- Division of Applied Mathematics, Brown University, Providence, Rhode Island, 02906
| | - Yuhao Qiang
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
| | - He Li
- School of Chemical, Materials and Biomedical Engineering, University of Georgia, Athens, Georgia, 30602
| | - Xuejin Li
- Department of Engineering Mechanics and Center for X-Mechanics, Zhejiang University, Hangzhou, Zhejiang 310027, China
| | - Pierre A. Buffet
- Université Paris Cité and Université des Antilles, Inserm, Biologie Intégrée du Globule Rouge, 75015, Paris, France
- Laboratoire d′Excellence du Globule Rouge, 75015, Paris, France
| | - Ming Dao
- Department of Materials Science and Engineering, Massachusetts Institute of Technology, Cambridge, Massachusetts, 02139
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5
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Rashidi Y, Simionato G, Zhou Q, John T, Kihm A, Bendaoud M, Krüger T, Bernabeu MO, Kaestner L, Laschke MW, Menger MD, Wagner C, Darras A. Red blood cell lingering modulates hematocrit distribution in the microcirculation. Biophys J 2023; 122:1526-1537. [PMID: 36932676 PMCID: PMC10147840 DOI: 10.1016/j.bpj.2023.03.020] [Citation(s) in RCA: 6] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Revised: 02/04/2023] [Accepted: 03/13/2023] [Indexed: 03/18/2023] Open
Abstract
The distribution of red blood cells (RBCs) in the microcirculation determines the oxygen delivery and solute transport to tissues. This process relies on the partitioning of RBCs at successive bifurcations throughout the microvascular network, and it has been known since the last century that RBCs partition disproportionately to the fractional blood flow rate, therefore leading to heterogeneity of the hematocrit (i.e., volume fraction of RBCs in blood) in microvessels. Usually, downstream of a microvascular bifurcation, the vessel branch with a higher fraction of blood flow receives an even higher fraction of RBC flux. However, both temporal and time-average deviations from this phase-separation law have been observed in recent studies. Here, we quantify how the microscopic behavior of RBC lingering (i.e., RBCs temporarily residing near the bifurcation apex with diminished velocity) influences their partitioning, through combined in vivo experiments and in silico simulations. We developed an approach to quantify the cell lingering at highly confined capillary-level bifurcations and demonstrate that it correlates with deviations of the phase-separation process from established empirical predictions by Pries et al. Furthermore, we shed light on how the bifurcation geometry and cell membrane rigidity can affect the lingering behavior of RBCs; e.g., rigid cells tend to linger less than softer ones. Taken together, RBC lingering is an important mechanism that should be considered when studying how abnormal RBC rigidity in diseases such as malaria and sickle-cell disease could hinder the microcirculatory blood flow or how the vascular networks are altered under pathological conditions (e.g., thrombosis, tumors, aneurysm).
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Affiliation(s)
- Yazdan Rashidi
- Experimental Physics, Saarland University, Saarbruecken, Germany.
| | - Greta Simionato
- Experimental Physics, Saarland University, Saarbruecken, Germany; Institute for Clinical and Experimental Surgery, Saarland University, Homburg, Germany
| | - Qi Zhou
- School of Engineering, Institute for Multiscale Thermofluids, University of Edinburgh, Edinburgh, United Kingdom
| | - Thomas John
- Experimental Physics, Saarland University, Saarbruecken, Germany
| | - Alexander Kihm
- Experimental Physics, Saarland University, Saarbruecken, Germany
| | - Mohammed Bendaoud
- Experimental Physics, Saarland University, Saarbruecken, Germany; Université Grenoble Alpes, CNRS, LIPhy, Grenoble, France; LaMCScI, Faculty of Sciences, Mohammed V University of Rabat, Rabat, Morocco
| | - Timm Krüger
- School of Engineering, Institute for Multiscale Thermofluids, University of Edinburgh, Edinburgh, United Kingdom
| | - Miguel O Bernabeu
- Centre for Medical Informatics, Usher Institute, University of Edinburgh, Edinburgh, United Kingdom; The Bayes Centre, University of Edinburgh, Edinburgh, United Kingdom
| | - Lars Kaestner
- Experimental Physics, Saarland University, Saarbruecken, Germany; Theoretical Medicine and Biosciences, Saarland University, Homburg, Germany
| | - Matthias W Laschke
- Institute for Clinical and Experimental Surgery, Saarland University, Homburg, Germany
| | - Michael D Menger
- Institute for Clinical and Experimental Surgery, Saarland University, Homburg, Germany
| | - Christian Wagner
- Experimental Physics, Saarland University, Saarbruecken, Germany; Physics and Materials Science Research Unit, University of Luxembourg, Luxembourg, Luxembourg
| | - Alexis Darras
- Experimental Physics, Saarland University, Saarbruecken, Germany.
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6
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Xiao L, Chu J, Lin C, Zhang K, Chen S, Yang L. Simulation of a tumor cell flowing through a symmetric bifurcated microvessel. Biomech Model Mechanobiol 2023; 22:297-308. [PMID: 36287312 DOI: 10.1007/s10237-022-01649-3] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/30/2022] [Accepted: 10/08/2022] [Indexed: 11/24/2022]
Abstract
Microvessel bifurcations serve as the major sites of tumor cell adhesion and further extravasation. In this study, the movement, deformation, and adhesion of a circulating tumor cell flowing in a symmetric microvessel with diverging and converging bifurcations were simulated by dissipative particle dynamics combined with a spring-based network model. Effects of the initial position of the CTC, externally-applied acceleration and the presence of RBCs on the motion of the CTC were investigated. The results demonstrated that the CTC released at the centerline of the parent vessel would attach to the vessel wall when arriving at the apex of diverging bifurcation and slide into the daughter branch determined by its centroid deflection and finally form firm adhesion at relatively lower flow rates. As the external acceleration increases, the increasing shear force enlarges the contact area for the adherent CTC on the one hand and reduces the residence time on the other hand. With the presence of RBCs in the bloodstream, the collision between the adherent tumor cell at the diverging bifurcation and flowing RBCs promotes the firm adhesion of CTC at lower flow rates.
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Affiliation(s)
- Lanlan Xiao
- School of Mechanical and Automotive Engineering, Shanghai University of Engineering Science, Shanghai, China
| | - Jie Chu
- School of Mechanical and Automotive Engineering, Shanghai University of Engineering Science, Shanghai, China
| | - Chensen Lin
- Artificial Intelligence Innovation and Incubation Institute, Fudan University, Shanghai, China.
| | - Kaixuan Zhang
- School of Medicine, Nankai University, Tianjin, China
| | - Shuo Chen
- School of Aerospace Engineering and Applied Mechanics, Tongji University, Shanghai, China
| | - Liu Yang
- Department of Mechanical Engineering, The Hong Kong Polytechnic University, Hong Kong, China
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7
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Maung Ye SS, Kim S. A mechanistic model of cross-bridge migration in RBC aggregation and disaggregation. Front Bioeng Biotechnol 2022; 10:1049878. [PMID: 36561046 PMCID: PMC9763627 DOI: 10.3389/fbioe.2022.1049878] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2022] [Accepted: 11/21/2022] [Indexed: 12/12/2022] Open
Abstract
Red blood cells (RBCs) clump together under low flow conditions in a process called RBC aggregation, which can alter RBC perfusion in a microvascular network. As elevated RBC aggregation is commonly associated with cardiovascular and inflammatory diseases, a better understanding of aggregation is essential. Unlike RBC aggregation in polymer solutions which can be well explained by polymer depletion theory, plasma-mediated RBC aggregation has features that best match explanations with cross-bridging mechanisms. Previous studies have demonstrated the dominant role of fibrinogen (Fg) in promoting aggregate formation and recent cell-force spectroscopy (CFS) experiments on interacting RBC doublets in plasma have reported an inverse relationship between disaggregation force and the adhesive contact area between RBCs. This has led investigators to revisit the hypothesis of inter-RBC cross-bridging which involves cross-bridge migration under interfacial tension during the forced disaggregation of RBC aggregates. In this study, we developed the cross-bridge migration model (CBMM) in plasma that mechanistically represents the migrating cross-bridge hypothesis. Transport of mobile Fg cross-bridges (mFg) was calculated using a convection-diffusion transport equation with our novel introduction of convective cross-bridge drift that arises due to intercellular friction. By parametrically transforming the diffusivity of mFg in the CBMM, we were able to match experimental observations of both RBC doublet formation kinematics and RBC doublet disaggregation forces under optical tweezers tension. We found that non-specific cross-bridging promotes spontaneous growth of adhesion area between RBC doublets whereas specific cross-bridging tends to prevent adhesion area growth. Our CBMM was also able to correlate Fg concentration shifts from healthy population blood plasma to SLE (lupus) condition blood plasma with the observed increase in doublet disaggregation forces for the RBC doublets in SLE plasma.
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8
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Maurya A, Murallidharan JS, Sharma A, Agarwal A. Microfluidics geometries involved in effective blood plasma separation. MICROFLUIDICS AND NANOFLUIDICS 2022; 26:73. [PMID: 36090664 PMCID: PMC9440999 DOI: 10.1007/s10404-022-02578-4] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Accepted: 08/09/2022] [Indexed: 06/15/2023]
Abstract
The last two decades witnessed a significant advancement in the field of diluted and whole blood plasma separation. This is one of the common procedures used to diagnose, cure and treat numerous acute and chronic diseases. For this separation purpose, various types of geometries of microfluidic devices, such as T-channel, Y-channel, trifurcation, constriction-expansion, curved/bend/spiral channels, a combination of any of the two geometries, etc., are being exploited, and this is detailed in this review article. The evaluation of the performance of such devices is based on the several parameters such as separation efficiency, flow rate, hematocrits, channel dimensions, etc. Thus, the current extensive review article endeavours to understand how particular geometry influences the separation efficiency for a given hematocrit. Additionally, a comparative analysis of various geometries is presented to demonstrate the less explored geometric configuration for the diluted and whole blood plasma separation. Also, a meta-analysis has been performed to highlight which geometry serves best to give a consistent separation efficiency. This article also presents tabulated data for various geometries with necessary details required from a designer's perspective such as channel dimensions, targeted component, studied range of hematocrit and flow rate, separation efficiency, etc. The maximum separation efficiency that can be achieved for a given hematocrits and geometry has also been plotted. The current review highlights the critical findings relevant to this field, state of the art understanding and the future challenges.
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Affiliation(s)
- Anamika Maurya
- Department of Mechanical Engineering, Indian Institute of Technology Mumbai, Mumbai, 400076 India
| | | | - Atul Sharma
- Department of Mechanical Engineering, Indian Institute of Technology Mumbai, Mumbai, 400076 India
| | - Amit Agarwal
- Department of Mechanical Engineering, Indian Institute of Technology Mumbai, Mumbai, 400076 India
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9
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Triebold C, Barber J. Dependence of red blood cell dynamics in microvessel bifurcations on the endothelial surface layer's resistance to flow and compression. Biomech Model Mechanobiol 2022; 21:771-796. [PMID: 35146594 DOI: 10.1007/s10237-022-01560-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2021] [Accepted: 01/11/2022] [Indexed: 11/30/2022]
Abstract
Red blood cells (RBCs) make up 40-45% of blood and play an important role in oxygen transport. That transport depends on the RBC distribution throughout the body, which is highly heterogeneous. That distribution, in turn, depends on how RBCs are distributed or partitioned at diverging vessel bifurcations where blood flows from one vessel into two. Several studies have used mathematical modeling to consider RBC partitioning at such bifurcations in order to produce useful insights. These studies, however, assume that the vessel wall is a flat impenetrable homogeneous surface. While this is a good first approximation, especially for larger vessels, the vessel wall is typically coated by a flexible, porous endothelial glycocalyx or endothelial surface layer (ESL) that is on the order of 0.5-1 µm thick. To better understand the possible effects of this layer on RBC partitioning, a diverging capillary bifurcation is analyzed using a flexible, two-dimensional model. In addition, the model is also used to investigate RBC deformation and RBC penetration of the ESL region when ESL properties are varied. The RBC is represented using interconnected viscoelastic elements. Stokes flow equations (viscous flow) model the surrounding fluid. The flow in the ESL is modeled using the Brinkman approximation for porous media with a corresponding hydraulic resistivity. The ESL's resistance to compression is modeled using an osmotic pressure difference. One cell passes through the bifurcation at a time, so there are no cell-cell interactions. A range of physiologically relevant hydraulic resistivities and osmotic pressure differences are explored. Decreasing hydraulic resistivity and/or decreasing osmotic pressure differences (ESL resistance to compression) produced four behaviors: (1) RBC partitioning nonuniformity increased slightly; (2) RBC deformation decreased; (3) RBC velocity decreased relative to blood flow velocity; and (4) RBCs penetrated more deeply into the ESL. Decreasing the ESL's resistance to flow and/or compression to pathological levels could lead to more frequent cell adhesion and clotting as well as impaired vascular regulation due to weaker ATP and nitric oxide release. Potential mechanisms that can contribute to these behaviors are also discussed.
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Affiliation(s)
- Carlson Triebold
- Department of Mathematical Sciences, Indiana University - Purdue University Indianapolis, Indianapolis, USA
| | - Jared Barber
- Department of Mathematical Sciences, Indiana University - Purdue University Indianapolis, Indianapolis, USA.
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10
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Hyakutake T, Abe H, Miyoshi Y, Yasui M, Suzuki R, Tsurumaki S, Tsutsumi Y. In vitro study on the partitioning of red blood cells using a microchannel network. Microvasc Res 2021; 140:104281. [PMID: 34871649 DOI: 10.1016/j.mvr.2021.104281] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/18/2021] [Revised: 11/11/2021] [Accepted: 11/13/2021] [Indexed: 11/18/2022]
Abstract
To investigate the partitioning properties of red blood cells (RBCs) in the bifurcating capillary vessels, an in vitro experiment was performed to perfuse human RBC suspensions into the microfluidic channels with a width of <10 μm. Two types of microchannel geometries were established. One is a single model comprising one parent and two daughter channels with different widths, and the other is a network model that had a symmetric geometry with four consecutive divergences and convergences. In addition to the fractional RBC flux at each bifurcation, changes in hematocrit levels and flow velocity before and after the bifurcation were investigated. In the single model, non-uniform partitioning of RBCs was observed, and this result was in good agreement with that of the empirical model. Furthermore, in the network model, the RBC distribution in the cross-section before the bifurcation significantly affected RBC partitioning in the two channels after the bifurcation. Hence, there was a large RBC heterogeneity in the capillary network. The hematocrit levels between the channels differed for more than one order of magnitude. Therefore, the findings of the current research could facilitate a better understanding of RBC partitioning properties in the microcirculatory system.
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Affiliation(s)
- Toru Hyakutake
- Faculty of Engineering, Yokohama National University, 79-5, Hodogaya, Yokohama 240-8501, Japan.
| | - Hiroki Abe
- Graduate School of Engineering, Yokohama National University, 79-5, Hodogaya, Yokohama 240-8501, Japan
| | - Yohei Miyoshi
- Graduate School of Engineering, Yokohama National University, 79-5, Hodogaya, Yokohama 240-8501, Japan
| | - Manabu Yasui
- Kanagawa Institute of Industrial Science and Technology, 705-1, Shimoimaizumi, Ebina 243-0435, Japan
| | - Rina Suzuki
- Graduate School of Engineering, Yokohama National University, 79-5, Hodogaya, Yokohama 240-8501, Japan
| | - Shunto Tsurumaki
- Graduate School of Engineering, Yokohama National University, 79-5, Hodogaya, Yokohama 240-8501, Japan
| | - Yuya Tsutsumi
- Graduate School of Engineering, Yokohama National University, 79-5, Hodogaya, Yokohama 240-8501, Japan
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11
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Ye T, Zhang X, Li G, Wang S. Biomechanics in thrombus formation from direct cellular simulations. Phys Rev E 2021; 102:042410. [PMID: 33212741 DOI: 10.1103/physreve.102.042410] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/05/2020] [Accepted: 10/02/2020] [Indexed: 11/07/2022]
Abstract
Numerically reproducing the process of thrombus formation is highly desired for understanding its mechanism but still remains challenging due to the polydisperse feature of blood components and their multiple biochemical or biomechanical behaviors involved. We numerically implemented a simplified version of the process from the perspective of biomechanics, using a mesoscale particle-based method, smoothed dissipative particle dynamics-immersed boundary method. This version covers the adhesion and aggregation of platelets (PLTs), the deformation and aggregation of red blood cells (RBCs), and the interaction between PLTs and RBCs, as well as the blockage of microvessels. Four critical factors that can affect thrombus formation were investigated: the velocity of blood flow, the adhesive ability of PLTs, the interaction strength between PLTs and RBCs, and the deformability of RBCs. Increasing the velocity of blood flow was found to be the most effective way to reduce the microvessel blockage, and reducing the adhesive ability of PLTs is also a direct and efficient way. However, decreasing the interaction strength between PLTs and RBCs sometimes does not alleviate thrombus formation, and similarly, increasing the deformability of RBCs does not have a significant improvement for the severely blocked microvessel. These results imply that maintaining high-rate blood flow plays a crucial role in the prevention and treatment of thrombosis, which is even more effective than antiplatelet or anticoagulant drugs. The drugs or treatments concentrating on reducing the PLT-RBC interaction or softening the RBCs may not have a significant effect on the thrombosis.
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Affiliation(s)
- Ting Ye
- Department of Computational Mathematics, School of Mathematics, Jilin University, Changchun, 130012, China
| | - Xuejiao Zhang
- Department of Computational Mathematics, School of Mathematics, Jilin University, Changchun, 130012, China
| | - Guansheng Li
- Department of Computational Mathematics, School of Mathematics, Jilin University, Changchun, 130012, China
| | - Sitong Wang
- Department of Computational Mathematics, School of Mathematics, Jilin University, Changchun, 130012, China
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Zhou Q, Fidalgo J, Bernabeu MO, Oliveira MSN, Krüger T. Emergent cell-free layer asymmetry and biased haematocrit partition in a biomimetic vascular network of successive bifurcations. SOFT MATTER 2021; 17:3619-3633. [PMID: 33459318 DOI: 10.1039/d0sm01845g] [Citation(s) in RCA: 15] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/12/2023]
Abstract
Blood is a vital soft matter, and its normal circulation in the human body relies on the distribution of red blood cells (RBCs) at successive bifurcations. Understanding how RBCs are partitioned at bifurcations is key for the optimisation of microfluidic devices as well as for devising novel strategies for diagnosis and treatment of blood-related diseases. We report the dynamics of RBC suspensions flowing through a biomimetic vascular network incorporating three generations of microchannels and two classical types of bifurcations at the arteriole level. Our microfluidic experiments with dilute and semidilute RBC suspensions demonstrate the emergence of excessive heterogeneity of RBC concentration in downstream generations upon altering the network's outflow rates. Through parallel simulations using the immersed-boundary-lattice-Boltzmann method, we reveal that the heterogeneity is attributed to upstream perturbations in the cell-free layer (CFL) and lack of its recovery between consecutive bifurcations owing to suppressed hydrodynamic lift under reduced flow conditions. In the dilute/semidilute regime, this perturbation dominates over the effect of local fractional flow at the bifurcation and can lead to inherently unfavourable child branches that are deprived of RBCs even for equal flow split. Our work highlights the importance of CFL asymmetry cascading down a vascular network, which leads to biased phase separation that deviates from established empirical predictions.
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Affiliation(s)
- Qi Zhou
- School of Engineering, Institute for Multiscale Thermofluids, University of Edinburgh, Edinburgh EH9 3FB, UK.
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