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van Veluw SJ, Benveniste H, Bakker ENTP, Carare RO, Greenberg SM, Iliff JJ, Lorthois S, Van Nostrand WE, Petzold GC, Shih AY, van Osch MJP. Is CAA a perivascular brain clearance disease? A discussion of the evidence to date and outlook for future studies. Cell Mol Life Sci 2024; 81:239. [PMID: 38801464 PMCID: PMC11130115 DOI: 10.1007/s00018-024-05277-1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2023] [Revised: 04/20/2024] [Accepted: 05/13/2024] [Indexed: 05/29/2024]
Abstract
The brain's network of perivascular channels for clearance of excess fluids and waste plays a critical role in the pathogenesis of several neurodegenerative diseases including cerebral amyloid angiopathy (CAA). CAA is the main cause of hemorrhagic stroke in the elderly, the most common vascular comorbidity in Alzheimer's disease and also implicated in adverse events related to anti-amyloid immunotherapy. Remarkably, the mechanisms governing perivascular clearance of soluble amyloid β-a key culprit in CAA-from the brain to draining lymphatics and systemic circulation remains poorly understood. This knowledge gap is critically important to bridge for understanding the pathophysiology of CAA and accelerate development of targeted therapeutics. The authors of this review recently converged their diverse expertise in the field of perivascular physiology to specifically address this problem within the framework of a Leducq Foundation Transatlantic Network of Excellence on Brain Clearance. This review discusses the overarching goal of the consortium and explores the evidence supporting or refuting the role of impaired perivascular clearance in the pathophysiology of CAA with a focus on translating observations from rodents to humans. We also discuss the anatomical features of perivascular channels as well as the biophysical characteristics of fluid and solute transport.
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Affiliation(s)
- Susanne J van Veluw
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA.
| | - Helene Benveniste
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT, USA
| | - Erik N T P Bakker
- Department of Biomedical Engineering, Amsterdam University Medical Center, Location AMC, Amsterdam Neuroscience Research Institute, Amsterdam, The Netherlands
| | - Roxana O Carare
- Clinical Neurosciences, University of Southampton, Southampton, UK
| | - Steven M Greenberg
- Department of Neurology, Massachusetts General Hospital, Harvard Medical School, Boston, MA, USA
| | - Jeffrey J Iliff
- VA Puget Sound Health Care System, University of Washington, Seattle, WA, USA
| | - Sylvie Lorthois
- Institut de Mécanique Des Fluides de Toulouse, IMFT, Université de Toulouse, CNRS, Toulouse, France
| | - William E Van Nostrand
- Department of Biomedical and Pharmaceutical Science, George & Anne Ryan Institute for Neuroscience, University of Rhode Island, Kingston, RI, USA
| | - Gabor C Petzold
- German Center for Neurodegenerative Disease, Bonn, Germany
- Division of Vascular Neurology, Department of Neurology, University Hospital Bonn, Bonn, Germany
| | - Andy Y Shih
- Center for Developmental Biology and Regenerative Medicine, Seattle Children's Research Institute, University of Washington, Seattle, WA, USA
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2
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Pastor-Alonso D, Berg M, Boyer F, Fomin-Thunemann N, Quintard M, Davit Y, Lorthois S. Modeling oxygen transport in the brain: An efficient coarse-grid approach to capture perivascular gradients in the parenchyma. PLoS Comput Biol 2024; 20:e1011973. [PMID: 38781253 DOI: 10.1371/journal.pcbi.1011973] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/06/2023] [Accepted: 03/05/2024] [Indexed: 05/25/2024] Open
Abstract
Recent progresses in intravital imaging have enabled highly-resolved measurements of periarteriolar oxygen gradients (POGs) within the brain parenchyma. POGs are increasingly used as proxies to estimate the local baseline oxygen consumption, which is a hallmark of cell activity. However, the oxygen profile around a given arteriole arises from an interplay between oxygen consumption and delivery, not only by this arteriole but also by distant capillaries. Integrating such interactions across scales while accounting for the complex architecture of the microvascular network remains a challenge from a modelling perspective. This limits our ability to interpret the experimental oxygen maps and constitutes a key bottleneck toward the inverse determination of metabolic rates of oxygen. We revisit the problem of parenchymal oxygen transport and metabolism and introduce a simple, conservative, accurate and scalable direct numerical method going beyond canonical Krogh-type models and their associated geometrical simplifications. We focus on a two-dimensional formulation, and introduce the concepts needed to combine an operator-splitting and a Green's function approach. Oxygen concentration is decomposed into a slowly-varying contribution, discretized by Finite Volumes over a coarse cartesian grid, and a rapidly-varying contribution, approximated analytically in grid-cells surrounding each vessel. Starting with simple test cases, we thoroughly analyze the resulting errors by comparison with highly-resolved simulations of the original transport problem, showing considerable improvement of the computational-cost/accuracy balance compared to previous work. We then demonstrate the model ability to flexibly generate synthetic data reproducing the spatial dynamics of oxygen in the brain parenchyma, with sub-grid resolution. Based on these synthetic data, we show that capillaries distant from the arteriole cannot be overlooked when interpreting POGs, thus reconciling recent measurements of POGs across cortical layers with the fundamental idea that variations of vascular density within the depth of the cortex may reveal underlying differences in neuronal organization and metabolic load.
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Affiliation(s)
- David Pastor-Alonso
- Institut de Mécanique des Fluides de Toulouse (IMFT), UMR 5502, Université de Toulouse, CNRS, Toulouse, France
| | - Maxime Berg
- Institut de Mécanique des Fluides de Toulouse (IMFT), UMR 5502, Université de Toulouse, CNRS, Toulouse, France
- Department of Mechanical Engineering, University College London, London, United Kingdom
| | - Franck Boyer
- Institut de Mathématiques de Toulouse (IMT), UMR 5219, Université de Toulouse, CNRS, UPS, Toulouse, France
| | - Natalie Fomin-Thunemann
- Department of Biomedical Engineering, Boston University, Boston, Massachusetts, United States of America
| | - Michel Quintard
- Institut de Mécanique des Fluides de Toulouse (IMFT), UMR 5502, Université de Toulouse, CNRS, Toulouse, France
| | - Yohan Davit
- Institut de Mécanique des Fluides de Toulouse (IMFT), UMR 5502, Université de Toulouse, CNRS, Toulouse, France
| | - Sylvie Lorthois
- Institut de Mécanique des Fluides de Toulouse (IMFT), UMR 5502, Université de Toulouse, CNRS, Toulouse, France
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3
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Possenti L, Vitullo P, Cicchetti A, Zunino P, Rancati T. Modeling hypoxia-induced radiation resistance and the impact of radiation sources. Comput Biol Med 2024; 173:108334. [PMID: 38520919 DOI: 10.1016/j.compbiomed.2024.108334] [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: 01/12/2024] [Revised: 02/29/2024] [Accepted: 03/17/2024] [Indexed: 03/25/2024]
Abstract
Hypoxia contributes significantly to resistance in radiotherapy. Our research rigorously examines the influence of microvascular morphology on radiotherapy outcome, specifically focusing on how microvasculature shapes hypoxia within the microenvironment and affects resistance to a standard treatment regimen (30×2GyRBE). Our computational modeling extends to the effects of different radiation sources. For photons and protons, our analysis establishes a clear correlation between hypoxic volume distribution and treatment effectiveness, with vascular density and regularity playing a crucial role in treatment success. On the contrary, carbon ions exhibit distinct effectiveness, even in areas of intense hypoxia and poor vascularization. This finding points to the potential of carbon-based hadron therapy in overcoming hypoxia-induced resistance to RT. Considering that the spatial scale analyzed in this study is closely aligned with that of imaging data voxels, we also address the implications of these findings in a clinical context envisioning the possibility of detecting subvoxel hypoxia.
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Affiliation(s)
- Luca Possenti
- Data Science Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Via Venezian 1, Milan, 20133, Italy.
| | - Piermario Vitullo
- MOX, Department of Mathematics, Politecnico di Milano, P.zza Da Vinci 32, Milan, 20133, Italy
| | - Alessandro Cicchetti
- Data Science Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Via Venezian 1, Milan, 20133, Italy
| | - Paolo Zunino
- MOX, Department of Mathematics, Politecnico di Milano, P.zza Da Vinci 32, Milan, 20133, Italy
| | - Tiziana Rancati
- Data Science Unit, Fondazione IRCCS Istituto Nazionale dei Tumori, Via Venezian 1, Milan, 20133, Italy
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4
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Dong R, Liu S, Li Y, Gao F, Gao K, Chen C, Qian Z, Li W, Yang Y. Revisiting hemodynamics and blood oxygenation in a microfluidic microvasculature replica. Microvasc Res 2024; 152:104640. [PMID: 38065353 DOI: 10.1016/j.mvr.2023.104640] [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: 10/18/2023] [Revised: 11/25/2023] [Accepted: 12/03/2023] [Indexed: 02/03/2024]
Abstract
The complexity of microvascular circulation has led to the development of advanced imaging techniques and biomimetic models. This study developed a multifaceted microfluidic-based microdevice as an in vitro model of microvasculature to replicate important geometric and functional features of in vivo perfusion in mice. The microfluidic device consisted of a microchannel for blood perfusion, mirroring the natural hierarchical branching vascular structures found in mice. Additionally, the device incorporated a steady gradient of oxygen (O2) which diffused through the polydimethylsiloxane (PDMS) layer, allowing for dynamic blood oxygenation. The assembled multi-layered microdevice was accompanied by a dual-modal imaging system that combined laser speckle contrast imaging (LSCI) and intrinsic signal optical imaging (ISOI) to visualize full-field blood flow distributions and blood O2 profiles. By closely reproducing in vivo blood perfusion and oxygenation conditions, this microvasculature model, in conjunction with numerical simulation results, can provide quantitative information on physiologically relevant hemodynamics and key O2 transport parameters that are not directly measurable in traditional animal studies.
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Affiliation(s)
- Rui Dong
- Department of Biomedical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Sijia Liu
- Department of Biomedical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Yuewu Li
- Department of Biomedical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Fan Gao
- Department of Biomedical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Keqiang Gao
- School of Pharmacy, Nanjing Medical University, Nanjing 211166, China
| | - Chunxiao Chen
- Department of Biomedical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Zhiyu Qian
- Department of Biomedical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China
| | - Weitao Li
- Department of Biomedical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
| | - Yamin Yang
- Department of Biomedical Engineering, Nanjing University of Aeronautics and Astronautics, Nanjing 210016, China.
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5
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Stathoulopoulos A, Passos A, Kaliviotis E, Balabani S. Partitioning of dense RBC suspensions in single microfluidic bifurcations: role of cell deformability and bifurcation angle. Sci Rep 2024; 14:535. [PMID: 38177195 PMCID: PMC10767057 DOI: 10.1038/s41598-023-49849-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2023] [Accepted: 12/12/2023] [Indexed: 01/06/2024] Open
Abstract
Red blood cells (RBCs) are a key determinant of human physiology and their behaviour becomes extremely heterogeneous as they navigate in narrow, bifurcating vessels in the microvasculature, affecting local haemodynamics. This is due to partitioning in bifurcations which is dependent on the biomechanical properties of RBCs, especially deformability. We examine the effect of deformability on the haematocrit distributions of dense RBC suspensions flowing in a single, asymmetric Y-shaped bifurcation, experimentally. Human RBC suspensions (healthy and artificially hardened) at 20% haematocrit (Ht) were perfused through the microchannels at different flow ratios between the outlet branches, and negligible inertia, and imaged to infer cell distributions. Notable differences in the shape of the haematocrit distributions were observed between healthy and hardened RBCs near the bifurcation apex. These lead to more asymmetric distributions for healthy RBCs in the daughter and outlet branches with cells accumulating near the inner channel walls, exhibiting distinct hematocrit peaks which are sharper for healthy RBCs. Although the hematocrit distributions differed locally, similar partitioning characteristics were observed for both suspensions. Comparisons with RBC distributions measured in a T-shaped bifurcation showed that the bifurcation angle affects the haematocrit characteristics of the healthy RBCs and not the hardened ones. The extent of RBC partitioning was found similar in both geometries and suspensions. The study highlights the differences between local and global characteristics which impact RBC distribution in more complex, multi-bifurcation networks.
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Affiliation(s)
- Antonios Stathoulopoulos
- FluME, Department of Mechanical Engineering, University College London (UCL), London, WC1E 7JE, UK
| | - Andreas Passos
- FluME, Department of Mechanical Engineering, University College London (UCL), London, WC1E 7JE, UK
- Department of Mechanical Engineering and Material Science Engineering, Cyprus University of Technology, Limassol, Cyprus
| | - Efstathios Kaliviotis
- Department of Mechanical Engineering and Material Science Engineering, Cyprus University of Technology, Limassol, Cyprus
| | - Stavroula Balabani
- FluME, Department of Mechanical Engineering, University College London (UCL), London, WC1E 7JE, UK.
- Wellcome/EPSRC Centre for Interventional and Surgical Sciences, University College London (UCL), London, UK.
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Giblin J, Kura S, Nunuez JLU, Zhang J, Kureli G, Jiang J, Boas DA, Chen IA. High throughput detection of capillary stalling events with Bessel beam two-photon microscopy. NEUROPHOTONICS 2023; 10:035009. [PMID: 37705938 PMCID: PMC10495839 DOI: 10.1117/1.nph.10.3.035009] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/02/2023] [Revised: 08/09/2023] [Accepted: 08/17/2023] [Indexed: 09/15/2023]
Abstract
Significance Brief disruptions in capillary flow, commonly referred to as capillary "stalling," have gained interest recently for their potential role in disrupting cerebral blood flow and oxygen delivery. Approaches to studying this phenomenon have been hindered by limited volumetric imaging rates and cumbersome manual analysis. The ability to precisely and efficiently quantify the dynamics of these events will be key in understanding their potential role in stroke and neurodegenerative diseases, such as Alzheimer's disease. Aim Our study aimed to demonstrate that the fast volumetric imaging rates offered by Bessel beam two-photon microscopy combined with improved data analysis throughput allows for faster and more precise measurement of capillary stall dynamics. Results We found that while our analysis approach was unable to achieve full automation, we were able to cut analysis time in half while also finding stalling events that were missed in traditional blind manual analysis. The resulting data showed that our Bessel beam system was captured more stalling events compared to optical coherence tomography, particularly shorter stalling events. We then compare differences in stall dynamics between a young and old group of mice as well as a demonstrate changes in stalling before and after photothrombotic model of stroke. Finally, we also demonstrate the ability to monitor arteriole dynamics alongside stall dynamics. Conclusions Bessel beam two-photon microscopy combined with high throughput analysis is a powerful tool for studying capillary stalling due to its ability to monitor hundreds of capillaries simultaneously at high frame rates.
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Affiliation(s)
- John Giblin
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
- Boston University, Neurophotonics Center, Boston, Massachusetts, United States
| | - Sreekanth Kura
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
- Boston University, Neurophotonics Center, Boston, Massachusetts, United States
| | - Juan Luis Ugarte Nunuez
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
- Boston University, Neurophotonics Center, Boston, Massachusetts, United States
| | - Juncheng Zhang
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
- Boston University, Neurophotonics Center, Boston, Massachusetts, United States
| | - Gulce Kureli
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
- Boston University, Neurophotonics Center, Boston, Massachusetts, United States
| | - John Jiang
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
- Boston University, Neurophotonics Center, Boston, Massachusetts, United States
| | - David A. Boas
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
- Boston University, Neurophotonics Center, Boston, Massachusetts, United States
| | - Ichun A. Chen
- Boston University, Department of Biomedical Engineering, Boston, Massachusetts, United States
- Boston University, Neurophotonics Center, Boston, Massachusetts, United States
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7
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Song S, Senoussi M, Escande P, Villoutreix P. Random walk informed heterogeneity detection reveals how the lymph node conduit network influences T cells collective exploration behavior. PLoS Comput Biol 2023; 19:e1011168. [PMID: 37224180 DOI: 10.1371/journal.pcbi.1011168] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/20/2022] [Accepted: 05/09/2023] [Indexed: 05/26/2023] Open
Abstract
Random walks on networks are widely used to model stochastic processes such as search strategies, transportation problems or disease propagation. A prominent example of such process is the dynamics of naive T cells within the lymph node while they are scanning for antigens. The observed T cells trajectories in small sub-volumes of the lymph node are well modeled as a random walk and they have been shown to follow the lymphatic conduit network as substrate for migration. One can then ask how does the connectivity patterns of the lymph node conduit network affect the T cells collective exploration behavior. In particular, does the network display properties that are uniform across the whole volume of the lymph node or can we distinguish some heterogeneities? We propose a workflow to accurately and efficiently define and compute these quantities on large networks, which enables us to characterize heterogeneities within a very large published dataset of Lymph Node Conduit Network. To establish the significance of our results, we compared the results obtained on the lymph node to null models of varying complexity. We identified significantly heterogeneous regions characterized as "remote regions" at the poles and next to the medulla, while a large portion of the network promotes uniform exploration by T cells.
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Affiliation(s)
- Solène Song
- Aix Marseille Univ, Université de Toulon, CNRS, LIS Turing Centre for Living Systems, Marseille, France
| | - Malek Senoussi
- Aix Marseille Univ, Université de Toulon, CNRS, LIS Turing Centre for Living Systems, Marseille, France
| | - Paul Escande
- Aix Marseille Univ, CNRS, Centrale Marseille, I2M, Marseille, France
| | - Paul Villoutreix
- Aix Marseille Univ, Université de Toulon, CNRS, LIS Turing Centre for Living Systems, Marseille, France
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Lee SH, Secchi E, Kang PK. Rapid formation of bioaggregates and morphology transition to biofilm streamers induced by pore-throat flows. Proc Natl Acad Sci U S A 2023; 120:e2204466120. [PMID: 36989304 PMCID: PMC10083537 DOI: 10.1073/pnas.2204466120] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/14/2022] [Accepted: 02/28/2023] [Indexed: 03/30/2023] Open
Abstract
Bioaggregates are condensed porous materials comprising microbes, organic and inorganic matters, and water. They are commonly found in natural and engineered porous media and often cause clogging. Despite their importance, the formation mechanism of bioaggregates in porous media systems is largely unknown. Through microfluidic experiments and direct numerical simulations of fluid flow, we show that the rapid bioaggregation is driven by the interplay of the viscoelastic nature of biomass and hydrodynamic conditions at pore throats. At an early stage, unique flow structures around a pore throat promote the biomass attachment at the throat. Then, the attached biomass fluidizes when the shear stress at the partially clogged pore throat reaches a critical value. After the fluidization, the biomass is displaced and accumulated in the expansion region of throats forming bioaggregates. We further find that such criticality in shear stress triggers morphological changes in bioaggregates from rounded- to streamer-like shapes. This knowledge was used to control the clogging of throats by tuning the flow conditions: When the shear stress at the throat exceeded the critical value, clogging was prevented. The bioaggregation process did not depend on the detailed pore-throat geometry, as we reproduced the same dynamics in various pore-throat geometries. This study demonstrates that pore-throat structures, which are ubiquitous in porous media systems, induce bioaggregation and can lead to abrupt disruptions in flow.
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Affiliation(s)
- Sang Hyun Lee
- Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, MN55455
| | - Eleonora Secchi
- Institute of Environmental Engineering, ETH Zürich, Zürich8093, Switzerland
| | - Peter K. Kang
- Department of Earth and Environmental Sciences, University of Minnesota, Minneapolis, MN55455
- Saint Anthony Falls Laboratory, University of Minnesota, Minneapolis, MN55455
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Zhou Q, Schirrmann K, Doman E, Chen Q, Singh N, Selvaganapathy PR, Bernabeu MO, Jensen OE, Juel A, Chernyavsky IL, Krüger T. Red blood cell dynamics in extravascular biological tissues modelled as canonical disordered porous media. Interface Focus 2022; 12:20220037. [PMID: 36325194 PMCID: PMC9560785 DOI: 10.1098/rsfs.2022.0037] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Accepted: 09/07/2022] [Indexed: 12/17/2022] Open
Abstract
The dynamics of blood flow in the smallest vessels and passages of the human body, where the cellular character of blood becomes prominent, plays a dominant role in the transport and exchange of solutes. Recent studies have revealed that the microhaemodynamics of a vascular network is underpinned by its interconnected structure, and certain structural alterations such as capillary dilation and blockage can substantially change blood flow patterns. However, for extravascular media with disordered microstructure (e.g. the porous intervillous space in the placenta), it remains unclear how the medium’s structure affects the haemodynamics. Here, we simulate cellular blood flow in simple models of canonical porous media representative of extravascular biological tissue, with corroborative microfluidic experiments performed for validation purposes. For the media considered here, we observe three main effects: first, the relative apparent viscosity of blood increases with the structural disorder of the medium; second, the presence of red blood cells (RBCs) dynamically alters the flow distribution in the medium; third, symmetry breaking introduced by moderate structural disorder can promote more homogeneous distribution of RBCs. Our findings contribute to a better understanding of the cell-scale haemodynamics that mediates the relationship linking the function of certain biological tissues to their microstructure.
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Affiliation(s)
- Qi Zhou
- School of Engineering, Institute for Multiscale Thermofluids, Edinburgh, UK
| | - Kerstin Schirrmann
- Manchester Centre for Nonlinear Dynamics, Manchester, UK
- Department of Physics and Astronomy, The University of Manchester, Manchester, UK
| | - Eleanor Doman
- Department of Mathematics, The University of Manchester, Manchester, UK
| | - Qi Chen
- Manchester Centre for Nonlinear Dynamics, Manchester, UK
- Department of Physics and Astronomy, The University of Manchester, Manchester, UK
| | - Naval Singh
- Manchester Centre for Nonlinear Dynamics, Manchester, UK
- Department of Physics and Astronomy, The University of Manchester, Manchester, UK
| | - P. Ravi Selvaganapathy
- Department of Mechanical Engineering, School of Biomedical Engineering, McMaster University, Hamilton, Canada
| | - Miguel O. Bernabeu
- Centre for Medical Informatics, The University of Edinburgh, Edinburgh, UK
- The Bayes Centre, The University of Edinburgh, Edinburgh, UK
| | - Oliver E. Jensen
- Department of Mathematics, The University of Manchester, Manchester, UK
| | - Anne Juel
- Manchester Centre for Nonlinear Dynamics, Manchester, UK
- Department of Physics and Astronomy, The University of Manchester, Manchester, UK
| | - Igor L. Chernyavsky
- Department of Mathematics, The University of Manchester, Manchester, UK
- Maternal and Fetal Health Research Centre, School of Medical Sciences, The University of Manchester, Manchester, UK
| | - Timm Krüger
- School of Engineering, Institute for Multiscale Thermofluids, Edinburgh, UK
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Wang G, Chen Z, Song Y, Wu H, Chen M, Lai S, Wu X. Xueshuantong injection alleviates cerebral microcirculation disorder in middle cerebral artery occlusion/reperfusion rats by suppressing inflammation via JNK mediated JAK2/STAT3 and NF-κB signaling pathways. JOURNAL OF ETHNOPHARMACOLOGY 2022; 298:115592. [PMID: 35931304 DOI: 10.1016/j.jep.2022.115592] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 06/15/2022] [Revised: 07/17/2022] [Accepted: 07/28/2022] [Indexed: 06/15/2023]
Abstract
ETHNOPHARMACOLOGICAL RELEVANCE In the long history of traditional Chinese medicine, Panax notoginseng has been used as a key herb for the treatment of blood diseases. Brain microvessels support adequate blood circulation to maintain normal physiological function, therefore, brain microcirculation disorder is an important therapeutic target for various brain diseases. However, the role of Xueshuantong (XST) injection composed of saponins from P. Notoginseng (PNS) in the amelioration of cerebral microcirculation disorder is unclear. AIMS OF THE STUDY Cerebral microcirculation disorder and inflammation play a vital role in stroke. Capillary endothelial cells and adjacent tight junctions are fundamental to the structure and function of cerebrovascule. XST injection has been used clinically in the treatment of stroke, but no studies have reported its indication in cerebral microcirculation disorder. This study is to explore the action and mechanism of XST injection in the alleviation of cerebral microcirculation disorder in middle cerebral artery occlusion/reperfusion (MCAO/R) rats. MATERIALS AND METHODS MCAO/R rats and LPS-induced bEnd.3 cells were employed for the investigation of effect and mechanism of XST injection. Brain damages were evaluated by neurobehavioral assessment, 2, 3, 5-triphenyltetrazolium chloride (TTC) staining, hematoxylin and eosin staining (H&E), and Nissl staining. Morphology and density changes of cerebral microvessels were monitored by immunohistochemistry. Cell permeability was detected by measurement of trans-endothelial electrical resistance (TEER) and sodium fluorescein (NaF) leakage. The mRNA and protein expressions of inflammatory cytokines, tight junction proteins, adhesion molecules, Janus kinase 2 (JAK2), signal transducer and activator of transcription-3 (STAT3), inhibitor of NF-κB (IκB), nuclear factor-κB (NF-κB) and c-jun N-terminal kinase (JNK) in brain microvessels and lipopolysaccharide (LPS)-induced bEnd.3 cells were measured by real-time PCR and Western blot, respectively. RESULTS XST injection at 48 mg/kg significantly improved the neurological damage, inflammatory infiltration, and microvessel morphology, and increased microvessel density in brain of MCAO/R rats. The endothelial permeability was significantly mitigated by XST injection in LPS-induced bEnd.3 cells. Meanwhile, the tight junction proteins such as zona occludens 1 (ZO-1) and occludin were elevated remarkably in brain microvessel of MCAO/R rats and LPS-induced bEnd.3 cells. Moreover, the expression of inflammatory mediators including interleukin (IL)-1β, IL-6, tumor necrosis factor (TNF)-α, inducible nitric oxide synthase (iNOS), cycloocygenases 2 (COX-2), vascular cellular adhesion molecule-1 (VCAM-1), matrix metalloproteinase (MMP)-2, and MMP-9 were inhibited by XST injection. In addition, XST injection suppressed the phosphorylation of JAK2, STAT3, IκB, NF-κB and JNK, which could be abolished by anisomycin, the JNK agonist. CONCLUSION XST injection improved cerebral microvescular structure damage and dysfunction in MCAO/R rats through inhibiting inflammation activated by JNK mediated JAK2/STAT3 and NF-κB signaling pathways. The novel findings may provide theoretical basis for the clinical application in the treatment of cerebral microcirculation disorder.
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Affiliation(s)
- Gaorui Wang
- Shanghai Key Laboratory of Compound Chinese Medicines, The Ministry of Education (MOE) Key Laboratory for Standardization of Chinese Medicines, The State Administration of TCM (SATCM) Key Laboratory for New Resources and Quality Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Ziyu Chen
- Shanghai Key Laboratory of Compound Chinese Medicines, The Ministry of Education (MOE) Key Laboratory for Standardization of Chinese Medicines, The State Administration of TCM (SATCM) Key Laboratory for New Resources and Quality Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Yingying Song
- Shanghai Key Laboratory of Compound Chinese Medicines, The Ministry of Education (MOE) Key Laboratory for Standardization of Chinese Medicines, The State Administration of TCM (SATCM) Key Laboratory for New Resources and Quality Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Hui Wu
- Shanghai Key Laboratory of Compound Chinese Medicines, The Ministry of Education (MOE) Key Laboratory for Standardization of Chinese Medicines, The State Administration of TCM (SATCM) Key Laboratory for New Resources and Quality Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
| | - Ming Chen
- Guangxi Key Laboratory of Comprehensive Utilization Technology of Pseudo-ginseng, Wu Zhou, China.
| | - Shusheng Lai
- Guangxi Key Laboratory of Comprehensive Utilization Technology of Pseudo-ginseng, Wu Zhou, China.
| | - Xiaojun Wu
- Shanghai Key Laboratory of Compound Chinese Medicines, The Ministry of Education (MOE) Key Laboratory for Standardization of Chinese Medicines, The State Administration of TCM (SATCM) Key Laboratory for New Resources and Quality Evaluation of Chinese Medicine, Institute of Chinese Materia Medica, Shanghai University of Traditional Chinese Medicine, Shanghai, China.
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Abstract
We review theoretical and numerical models of the glymphatic system, which circulates cerebrospinal fluid and interstitial fluid around the brain, facilitating solute transport. Models enable hypothesis development and predictions of transport, with clinical applications including drug delivery, stroke, cardiac arrest, and neurodegenerative disorders like Alzheimer’s disease. We sort existing models into broad categories by anatomical function: Perivascular flow, transport in brain parenchyma, interfaces to perivascular spaces, efflux routes, and links to neuronal activity. Needs and opportunities for future work are highlighted wherever possible; new models, expanded models, and novel experiments to inform models could all have tremendous value for advancing the field.
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Xue Y, Georgakopoulou T, van der Wijk AE, Józsa TI, van Bavel E, Payne SJ. Quantification of hypoxic regions distant from occlusions in cerebral penetrating arteriole trees. PLoS Comput Biol 2022; 18:e1010166. [PMID: 35930591 PMCID: PMC9385041 DOI: 10.1371/journal.pcbi.1010166] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/05/2022] [Revised: 08/17/2022] [Accepted: 07/14/2022] [Indexed: 11/18/2022] Open
Abstract
The microvasculature plays a key role in oxygen transport in the mammalian brain. Despite the close coupling between cerebral vascular geometry and local oxygen demand, recent experiments have reported that microvascular occlusions can lead to unexpected distant tissue hypoxia and infarction. To better understand the spatial correlation between the hypoxic regions and the occlusion sites, we used both in vivo experiments and in silico simulations to investigate the effects of occlusions in cerebral penetrating arteriole trees on tissue hypoxia. In a rat model of microembolisation, 25 μm microspheres were injected through the carotid artery to occlude penetrating arterioles. In representative models of human cortical columns, the penetrating arterioles were occluded by simulating the transport of microspheres of the same size and the oxygen transport was simulated using a Green’s function method. The locations of microspheres and hypoxic regions were segmented, and two novel distance analyses were implemented to study their spatial correlation. The distant hypoxic regions were found to be present in both experiments and simulations, and mainly due to the hypoperfusion in the region downstream of the occlusion site. Furthermore, a reasonable agreement for the spatial correlation between hypoxic regions and occlusion sites is shown between experiments and simulations, which indicates the good applicability of in silico models in understanding the response of cerebral blood flow and oxygen transport to microemboli. The brain function depends on the continuous oxygen supply through the bloodstream inside the microvasculature. Occlusions in the microvascular network will disturb the oxygen delivery in the brain and result in hypoxic tissues that can lead to infarction and cognitive dysfunction. To aid in understanding the formation of hypoxic tissues caused by micro-occlusions in the penetrating arteriole trees, we use rodent experiments and simulations of human vascular networks to study the spatial correlations between the hypoxic regions and the occlusion locations. Our results suggest that hypoxic regions can form distally from the occlusion site, which agrees with the previous observations in the rat brain. These distant hypoxic regions are primarily due to the lack of blood flow in the brain tissues downstream of the occlusion. Moreover, a reasonable agreement of the spatial relationship is found between the experiments and the simulations, which indicates the applicability of in silico models to study the effects of microemboli on the brain tissue.
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Affiliation(s)
- Yidan Xue
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, United Kingdom
| | - Theodosia Georgakopoulou
- Department of Biomedical Engineering and Physics, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Anne-Eva van der Wijk
- Department of Biomedical Engineering and Physics, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Tamás I. Józsa
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, United Kingdom
| | - Ed van Bavel
- Department of Biomedical Engineering and Physics, Amsterdam University Medical Centers, University of Amsterdam, Amsterdam, The Netherlands
| | - Stephen J. Payne
- Institute of Biomedical Engineering, Department of Engineering Science, University of Oxford, Oxford, United Kingdom
- Institute of Applied Mechanics, National Taiwan University, Taipei, Taiwan
- * E-mail:
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13
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Bennett HC, Kim Y. Advances in studying whole mouse brain vasculature using high-resolution 3D light microscopy imaging. NEUROPHOTONICS 2022; 9:021902. [PMID: 35402638 PMCID: PMC8983067 DOI: 10.1117/1.nph.9.2.021902] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 11/30/2021] [Accepted: 03/11/2022] [Indexed: 06/14/2023]
Abstract
Significance: The cerebrovasculature has become increasingly recognized as a major player in overall brain health and many brain disorders. Although there have been several landmark studies to understand details of these crucially important structures in an anatomically defined area, brain-wide examination of the whole cerebrovasculature, including microvessels, has been challenging. However, emerging techniques, including tissue processing and three-dimensional (3D) microscopy imaging, enable neuroscientists to examine the total vasculature in the entire mouse brain. Aim: Here, we aim to highlight advances in these high-resolution 3D mapping methods including block-face imaging and light sheet fluorescent microscopy. Approach: We summarize latest mapping tools to understand detailed anatomical arrangement of the cerebrovascular network and the organizing principles of the neurovascular unit (NVU) as a whole. Results: We discuss biological insights gained from studies using these imaging methods and how these tools can be used to advance our understanding of the cerebrovascular network and related cell types in the entire brain. Conclusions: This review article will help to understand recent advance in high-resolution NVU mapping in mice and provide perspective on future studies.
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Affiliation(s)
- Hannah C. Bennett
- The Pennsylvania State University, Department of Neural and Behavioral Sciences, Hershey, Pennsylvania, United States
| | - Yongsoo Kim
- The Pennsylvania State University, Department of Neural and Behavioral Sciences, Hershey, Pennsylvania, United States
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14
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Merlo A, Berg M, Duru P, Risso F, Davit Y, Lorthois S. A few upstream bifurcations drive the spatial distribution of red blood cells in model microfluidic networks. SOFT MATTER 2022; 18:1463-1478. [PMID: 35088062 DOI: 10.1039/d1sm01141c] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/14/2023]
Abstract
The physics of blood flow in small vessel networks is dominated by the interactions between Red Blood Cells (RBCs), plasma and blood vessel walls. The resulting couplings between the microvessel network architecture and the heterogeneous distribution of RBCs at network-scale are still poorly understood. The main goal of this paper is to elucidate how a local effect, such as RBC partitioning at individual bifurcations, interacts with the global structure of the flow field to induce specific preferential locations of RBCs in model microfluidic networks. First, using experimental results, we demonstrate that persistent perturbations to the established hematocrit profile after diverging bifurcations may bias RBC partitioning at the next bifurcations. By performing a sensitivity analysis based upon network models of RBC flow, we show that these perturbations may propagate from bifurcation to bifurcation, leading to an outsized impact of a few crucial upstream bifurcations on the distribution of RBCs at network-scale. Based on measured hematocrit profiles, we further construct a modified RBC partitioning model that accounts for the incomplete relaxation of RBCs at these bifurcations. This model allows us to explain how the flow field results in a single pattern of RBC preferential location in some networks, while it leads to the emergence of two different patterns of RBC preferential location in others. Our findings have important implications in understanding and modeling blood flow in physiological and pathological conditions.
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Affiliation(s)
- Adlan Merlo
- Institut de Mécanique des Fluides de Toulouse, IMFT, Université de Toulouse, CNRS, Toulouse, France.
| | - Maxime Berg
- Institut de Mécanique des Fluides de Toulouse, IMFT, Université de Toulouse, CNRS, Toulouse, France.
| | - Paul Duru
- Institut de Mécanique des Fluides de Toulouse, IMFT, Université de Toulouse, CNRS, Toulouse, France.
| | - Frédéric Risso
- Institut de Mécanique des Fluides de Toulouse, IMFT, Université de Toulouse, CNRS, Toulouse, France.
| | - Yohan Davit
- Institut de Mécanique des Fluides de Toulouse, IMFT, Université de Toulouse, CNRS, Toulouse, France.
| | - Sylvie Lorthois
- Institut de Mécanique des Fluides de Toulouse, IMFT, Université de Toulouse, CNRS, Toulouse, France.
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