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Dong R, Liu W, Han Y, Wang Z, Jiang L, Wang L, Gu X. Influencing factors of glymphatic system during perioperative period. Front Neurosci 2024; 18:1428085. [PMID: 39328423 PMCID: PMC11424614 DOI: 10.3389/fnins.2024.1428085] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/23/2024] [Accepted: 08/23/2024] [Indexed: 09/28/2024] Open
Abstract
The glymphatic system is a functional cerebrospinal fluid circulatory system that uses peri-arterial space for inflow of cerebrospinal fluid and peri-venous space for efflux of cerebrospinal fluid from brain parenchyma. This brain-wide fluid transport pathway facilitates the exchange between cerebrospinal fluid and interstitial fluid and clears metabolic waste from the metabolically active brain. Multiple lines of work show that the glymphatic system is crucial to normal brain functions, and the dysfunction of the glymphatic system is closely associated with various neurological disorders, including aging, neurodegeneration, and acute brain injury. Currently, it is common to explore the functional and molecular mechanisms of the glymphatic system based on animal models. The function of glymphatic system during perioperative period is affected by many factors such as physiological, pathological, anesthetic and operative methods. To provide a reference for the interpretation of the results of glymphatic system studies during perioperative period, this article comprehensively reviews the physiological and pathological factors that interfere with the function of the glymphatic system during perioperative period, investigates the effects of anesthetic drugs on glymphatic system function and the potential underlying mechanisms, describes operative methods that interfere with the function of the glymphatic system, and potential intervention strategies based on the glymphatic system. Future, these variables should be taken into account as critical covariates in the design of functional studies on the glymphatic system.
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Affiliation(s)
- Rui Dong
- Department of Anesthesiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China
- Department of Anesthesiology, Qingdao Municipal Hospital, Qingdao, China
- Key Laboratory of Anesthesiology and Resuscitation, Ministry of Education, Huazhong University of Science and Technology, Wuhan, China
| | - Wenjie Liu
- Department of Anesthesiology, Qingdao Municipal Hospital, Qingdao, China
| | - Yuqiang Han
- Department of Anesthesiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Zimo Wang
- Department of Anesthesiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Linhao Jiang
- Department of Anesthesiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China
| | - Liwei Wang
- Department of Anesthesiology, Xuzhou Central Hospital, Xuzhou, China
| | - Xiaoping Gu
- Department of Anesthesiology, Nanjing Drum Tower Hospital, The Affiliated Hospital of Nanjing University Medical School, Nanjing, China
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2
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Romera C, Riba M, Alsina R, Sartorio M, Vilaplana J, Pelegrí C, Del Valle J. Mouse brain contains age-dependent extraparenchymal granular structures and astrocytes, both reactive to natural IgM antibodies, linked to the fissura magna. Immun Ageing 2024; 21:56. [PMID: 39169358 PMCID: PMC11337560 DOI: 10.1186/s12979-024-00460-1] [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: 06/04/2024] [Accepted: 08/13/2024] [Indexed: 08/23/2024]
Abstract
BACKGROUND Mouse brains can contain specific polyglucosan aggregates known as Periodic Acid-Schiff (PAS)-granules. Generated in astrocytes, these granules increase with age and exhibit neo-epitopes of carbohydrate nature that are recognized by natural IgM antibodies (IgMs). The existence of neoepitopes on PAS granules suggests the presence of neoepitopes in other brain structures, and this is investigated here. To this end, brain sections from SAMP8 and ICR-CD1 mice were examined at different ages. RESULTS We have identified two novel structures that, apart from PAS granules, are recognized by natural IgMs. On one side, IgM reactive (IgM+) granular structures which are placed in the longitudinal fissure, the quadrigeminal cistern, and a region that extends from the quadrigeminal cistern to the interpeduncular cistern. This last region, located between the telencephalon and both the mesencephalon and diencephalon, is designated henceforth as the fissura magna, as it is indeed a fissure and the largest in the brain. As all these regions are extraparenchymal (EP), the IgM+ granules found in these zones have been named EP granules. These EP granules are mainly associated with fibroblasts and are not stained with PAS. On the other side, some IgM+ astrocytes have been found in the glia limitans, near the above-mentioned fissures. Remarkably, EP granules are more prevalent at younger ages, while the number of IgM+ astrocytes increases with age, similarly to the already described evolution of PAS granules. CONCLUSIONS The present work reports the presence of two brain-related structures that, apart from PAS granules, contain neo-epitopes of carbohydrate nature, namely EP granules and IgM+ astrocytes. We suggest that EP granules, associated to fibroblasts, may be part of a physiological function in brain clearance or brain-CSF immune surveillance, while both PAS granules and IgM+ astrocytes may be related to the increasing accumulation of harmful materials that occurs with age and linked to brain protective mechanisms. Moreover, the specific localisation of these EP granules and IgM+ astrocytes suggest the importance of the fissura magna in these brain-related cleaning and immune functions. The overall results reinforce the possible link between the fissura magna and the functioning of the glymphatic system.
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Affiliation(s)
- Clara Romera
- Secció de Fisiologia, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia i Ciències de L'Alimentació, Universitat de Barcelona, Barcelona, 08028, Spain
- Institut de Neurociències, Universitat de Barcelona, Barcelona, 08035, Spain
- Centros de Biomedicina en Red de Enfermedades Neurodegenerativas (CIBERNED), Madrid, 28031, Spain
| | - Marta Riba
- Secció de Fisiologia, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia i Ciències de L'Alimentació, Universitat de Barcelona, Barcelona, 08028, Spain
- Institut de Neurociències, Universitat de Barcelona, Barcelona, 08035, Spain
- Centros de Biomedicina en Red de Enfermedades Neurodegenerativas (CIBERNED), Madrid, 28031, Spain
| | - Raquel Alsina
- Secció de Fisiologia, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia i Ciències de L'Alimentació, Universitat de Barcelona, Barcelona, 08028, Spain
- Institut de Neurociències, Universitat de Barcelona, Barcelona, 08035, Spain
- Centros de Biomedicina en Red de Enfermedades Neurodegenerativas (CIBERNED), Madrid, 28031, Spain
| | - Marina Sartorio
- Secció de Fisiologia, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia i Ciències de L'Alimentació, Universitat de Barcelona, Barcelona, 08028, Spain
- Institut de Neurociències, Universitat de Barcelona, Barcelona, 08035, Spain
| | - Jordi Vilaplana
- Secció de Fisiologia, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia i Ciències de L'Alimentació, Universitat de Barcelona, Barcelona, 08028, Spain
- Institut de Neurociències, Universitat de Barcelona, Barcelona, 08035, Spain
- Centros de Biomedicina en Red de Enfermedades Neurodegenerativas (CIBERNED), Madrid, 28031, Spain
| | - Carme Pelegrí
- Secció de Fisiologia, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia i Ciències de L'Alimentació, Universitat de Barcelona, Barcelona, 08028, Spain.
- Institut de Neurociències, Universitat de Barcelona, Barcelona, 08035, Spain.
- Centros de Biomedicina en Red de Enfermedades Neurodegenerativas (CIBERNED), Madrid, 28031, Spain.
| | - Jaume Del Valle
- Secció de Fisiologia, Departament de Bioquímica i Fisiologia, Facultat de Farmàcia i Ciències de L'Alimentació, Universitat de Barcelona, Barcelona, 08028, Spain.
- Institut de Neurociències, Universitat de Barcelona, Barcelona, 08035, Spain.
- Centros de Biomedicina en Red de Enfermedades Neurodegenerativas (CIBERNED), Madrid, 28031, Spain.
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Ding G, Li L, Chopp M, Zhang L, Li Q, Luo H, Wei M, Zhang J, Boyd E, Zhang Z, Jiang Q. Velocity of cerebrospinal fluid in the aqueduct measured by phase-contrast MRI in rat. NMR IN BIOMEDICINE 2024:e5233. [PMID: 39104053 DOI: 10.1002/nbm.5233] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2023] [Revised: 04/15/2024] [Accepted: 07/22/2024] [Indexed: 08/07/2024]
Abstract
Cerebrospinal fluid (CSF) circulation plays a key role in cerebral waste clearance via the glymphatic system. Although CSF flow velocity is an essential component of CSF dynamics, it has not been sufficiently characterized, and particularly, in studies of the glymphatic system in rat. To investigate the relationship between the flow velocity of CSF in the brain aqueduct and the glymphatic waste clearance rate, using phase-contrast MRI we performed the first measurements of CSF velocity in rats. Phase-contrast MRI was performed using a 7 T system to map mean velocity of CSF flow in the aqueduct in rat brain. The effects of age (3 months old versus 18 months old), gender, strain (Wistar, RNU, Dark Agouti), anesthetic agents (isoflurane versus dexmedetomidine), and neurodegenerative disorder (Alzheimer' disease in Fischer TgF344-AD rats, males and females) on CSF velocity were investigated in eight independent groups of rats (12 rats per group). Our results demonstrated that quantitative velocities of CSF flow in the aqueduct averaged 5.16 ± 0.86 mm/s in healthy young adult male Wistar rats. CSF flow velocity in the aqueduct was not altered by rat gender, strain, and the employed anesthetic agents in all rats, also age in the female rats. However, aged (18 months) Wistar male rats exhibited significantly reduced the CSF flow velocity in the aqueduct (4.31 ± 1.08 mm/s). In addition, Alzheimer's disease further reduced the CSF flow velocity in the aqueduct of male and female rats.
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Affiliation(s)
- Guangliang Ding
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA
| | - Lian Li
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA
| | - Michael Chopp
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA
- Department of Physics, Oakland University, Rochester, MI, USA
| | - Li Zhang
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA
| | - Qingjiang Li
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA
| | - Hao Luo
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA
| | - Min Wei
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA
| | - Jing Zhang
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA
| | - Edward Boyd
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA
| | - Zhenggang Zhang
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA
| | - Quan Jiang
- Department of Neurology, Henry Ford Hospital, Detroit, MI, USA
- Department of Physics, Oakland University, Rochester, MI, USA
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4
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Smets NG, van der Panne SA, Strijkers GJ, Bakker ENTP. Perivascular spaces around arteries exceed perivenous spaces in the mouse brain. Sci Rep 2024; 14:17655. [PMID: 39085283 PMCID: PMC11291892 DOI: 10.1038/s41598-024-67885-y] [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: 04/24/2024] [Accepted: 07/17/2024] [Indexed: 08/02/2024] Open
Abstract
The perivascular space (PVS) surrounds cerebral blood vessels and plays an important role in clearing waste products from the brain. Their anatomy and function have been described for arteries, but PVS around veins remain poorly characterized. Using in vivo 2-photon imaging in mice, we determined the size of the PVS around arteries and veins, and their connection with the subarachnoid space. After infusion of 70 kD FITC-dextran into the cerebrospinal fluid via the cisterna magna, labeled PVS were evident around arteries, but veins showed less frequent labeling of the PVS. The size of the PVS correlated with blood vessel size for both pial arteries and veins, but not for penetrating vessels. The PVS around pial arteries and veins was separated from the subarachnoid space by a thin meningeal layer, which did not form a barrier for the tracer. In vivo, FITC-dextran signal was observed adjacent to the vessel wall, but minimally within the wall itself. Post-mortem, there was a significant shift in the tracer's location within the arterial wall, extending into the smooth muscle layer. Taken together, these findings suggest that the PVS around veins has a limited role in the exchange of solutes between CSF and brain parenchyma.
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Affiliation(s)
- Nina G Smets
- Department of Biomedical Engineering and Physics, Amsterdam University Medical Center, Amsterdam, The Netherlands
- Amsterdam Neuroscience Research Institute, Amsterdam, Netherlands
- Amsterdam Cardiovascular Sciences Research Institute, Amsterdam, Netherlands
| | - Shakira A van der Panne
- Department of Biomedical Engineering and Physics, Amsterdam University Medical Center, Amsterdam, The Netherlands
- Amsterdam Neuroscience Research Institute, Amsterdam, Netherlands
- Amsterdam Cardiovascular Sciences Research Institute, Amsterdam, Netherlands
| | - Gustav J Strijkers
- Department of Biomedical Engineering and Physics, Amsterdam University Medical Center, Amsterdam, The Netherlands
- Amsterdam Cardiovascular Sciences Research Institute, Amsterdam, Netherlands
| | - Erik N T P Bakker
- Department of Biomedical Engineering and Physics, Amsterdam University Medical Center, Amsterdam, The Netherlands.
- Amsterdam Neuroscience Research Institute, Amsterdam, Netherlands.
- Amsterdam Cardiovascular Sciences Research Institute, Amsterdam, Netherlands.
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5
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Hladky SB, Barrand MA. Regulation of brain fluid volumes and pressures: basic principles, intracranial hypertension, ventriculomegaly and hydrocephalus. Fluids Barriers CNS 2024; 21:57. [PMID: 39020364 PMCID: PMC11253534 DOI: 10.1186/s12987-024-00532-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Accepted: 03/21/2024] [Indexed: 07/19/2024] Open
Abstract
The principles of cerebrospinal fluid (CSF) production, circulation and outflow and regulation of fluid volumes and pressures in the normal brain are summarised. Abnormalities in these aspects in intracranial hypertension, ventriculomegaly and hydrocephalus are discussed. The brain parenchyma has a cellular framework with interstitial fluid (ISF) in the intervening spaces. Framework stress and interstitial fluid pressure (ISFP) combined provide the total stress which, after allowing for gravity, normally equals intracerebral pressure (ICP) with gradients of total stress too small to measure. Fluid pressure may differ from ICP in the parenchyma and collapsed subarachnoid spaces when the parenchyma presses against the meninges. Fluid pressure gradients determine fluid movements. In adults, restricting CSF outflow from subarachnoid spaces produces intracranial hypertension which, when CSF volumes change very little, is called idiopathic intracranial hypertension (iIH). Raised ICP in iIH is accompanied by increased venous sinus pressure, though which is cause and which effect is unclear. In infants with growing skulls, restriction in outflow leads to increased head and CSF volumes. In adults, ventriculomegaly can arise due to cerebral atrophy or, in hydrocephalus, to obstructions to intracranial CSF flow. In non-communicating hydrocephalus, flow through or out of the ventricles is somehow obstructed, whereas in communicating hydrocephalus, the obstruction is somewhere between the cisterna magna and cranial sites of outflow. When normal outflow routes are obstructed, continued CSF production in the ventricles may be partially balanced by outflow through the parenchyma via an oedematous periventricular layer and perivascular spaces. In adults, secondary hydrocephalus with raised ICP results from obvious obstructions to flow. By contrast, with the more subtly obstructed flow seen in normal pressure hydrocephalus (NPH), fluid pressure must be reduced elsewhere, e.g. in some subarachnoid spaces. In idiopathic NPH, where ventriculomegaly is accompanied by gait disturbance, dementia and/or urinary incontinence, the functional deficits can sometimes be reversed by shunting or third ventriculostomy. Parenchymal shrinkage is irreversible in late stage hydrocephalus with cellular framework loss but may not occur in early stages, whether by exclusion of fluid or otherwise. Further studies that are needed to explain the development of hydrocephalus are outlined.
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Affiliation(s)
- Stephen B Hladky
- Department of Pharmacology, Tennis Court Rd, Cambridge, CB2 1PD, UK.
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6
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Smets NG, Strijkers GJ, Vinje V, Bakker ENTP. Cerebrospinal fluid turnover as a driver of brain clearance. NMR IN BIOMEDICINE 2024; 37:e5029. [PMID: 37658736 DOI: 10.1002/nbm.5029] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 06/30/2023] [Accepted: 08/05/2023] [Indexed: 09/05/2023]
Abstract
Cerebrospinal fluid (CSF) has historically been considered to function as a sink for brain-derived waste disposal. Recent work suggested that CSF interacts even more intensely with brain tissue than previously recognized, through perivascular spaces that penetrate the brain. Cardiac pulsations, vasomotion, and respiration have been suggested to drive CSF flow in these perivascular spaces, thereby enhancing waste clearance. However, the intrinsic role of CSF production in relation to its distribution volume (turnover) is not an explicit component of recent concepts on brain clearance. Here, we review the work on CSF turnover and volume, focusing on preclinical evidence. Herein, we highlight the use of MRI in establishing CSF-related parameters. We describe the impact of sleep, effect of anesthesia, aging, and hypertension on CSF turnover, and how this relates to brain clearance. Evaluation of the available evidence suggests that CSF turnover is a major determinant in brain clearance. In addition, we propose that several putative drivers of brain clearance, but also conditions associated with impaired clearance, such as aging, may actually relate to altered CSF turnover.
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Affiliation(s)
- Nina G Smets
- Department of Biomedical Engineering and Physics, Amsterdam University Medical Center, location AMC, Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences Research Institute, Amsterdam, the Netherlands
- Amsterdam Neuroscience Research Institute, Amsterdam, the Netherlands
| | - Gustav J Strijkers
- Department of Biomedical Engineering and Physics, Amsterdam University Medical Center, location AMC, Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences Research Institute, Amsterdam, the Netherlands
| | | | - Erik N T P Bakker
- Department of Biomedical Engineering and Physics, Amsterdam University Medical Center, location AMC, Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences Research Institute, Amsterdam, the Netherlands
- Amsterdam Neuroscience Research Institute, Amsterdam, the Netherlands
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7
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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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8
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Lee EJ, Suh M, Choi H, Choi Y, Hwang DW, Bae S, Lee DS. Spatial transcriptomic brain imaging reveals the effects of immunomodulation therapy on specific regional brain cells in a mouse dementia model. BMC Genomics 2024; 25:516. [PMID: 38796425 PMCID: PMC11128132 DOI: 10.1186/s12864-024-10434-8] [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: 02/18/2024] [Accepted: 05/20/2024] [Indexed: 05/28/2024] Open
Abstract
Increasing evidence of brain-immune crosstalk raises expectations for the efficacy of novel immunotherapies in Alzheimer's disease (AD), but the lack of methods to examine brain tissues makes it difficult to evaluate therapeutics. Here, we investigated the changes in spatial transcriptomic signatures and brain cell types using the 10x Genomics Visium platform in immune-modulated AD models after various treatments. To proceed with an analysis suitable for barcode-based spatial transcriptomics, we first organized a workflow for segmentation of neuroanatomical regions, establishment of appropriate gene combinations, and comprehensive review of altered brain cell signatures. Ultimately, we investigated spatial transcriptomic changes following administration of immunomodulators, NK cell supplements and an anti-CD4 antibody, which ameliorated behavior impairment, and designated brain cells and regions showing probable associations with behavior changes. We provided the customized analytic pipeline into an application named STquantool. Thus, we anticipate that our approach can help researchers interpret the real action of drug candidates by simultaneously investigating the dynamics of all transcripts for the development of novel AD therapeutics.
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Affiliation(s)
- Eun Ji Lee
- Department of Nuclear Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
- Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Republic of Korea
| | - Minseok Suh
- Department of Nuclear Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Republic of Korea
- Institute of Radiation Medicine, Medical Research Center, Seoul National University, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
| | - Hongyoon Choi
- Department of Nuclear Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Republic of Korea
| | - Yoori Choi
- Department of Nuclear Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea
- Cliniclal Research Institute, Seoul National University Hospital, Seoul, Republic of Korea
| | - Do Won Hwang
- Research and Development Center, THERABEST Inc., Seocho-daero 40-gil, Seoul, 06657, Republic of Korea
| | - Sungwoo Bae
- Department of Nuclear Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea.
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Republic of Korea.
- Institute of Radiation Medicine, Medical Research Center, Seoul National University, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea.
| | - Dong Soo Lee
- Department of Nuclear Medicine, Seoul National University College of Medicine, 101 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea.
- Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Republic of Korea.
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Republic of Korea.
- Institute of Radiation Medicine, Medical Research Center, Seoul National University, 103 Daehak-ro, Jongno-gu, Seoul, 03080, Republic of Korea.
- Medical Science and Engineering, School of Convergence Science and Technology, POSTECH, Pohang, Republic of Korea.
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9
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Abstract
The brain is a complex organ, fundamentally changing across the day to perform basic functions like sleep, thought, and regulating whole-body physiology. This requires a complex symphony of nutrients, hormones, ions, neurotransmitters and more to be properly distributed across the brain to maintain homeostasis throughout 24 hours. These solutes are distributed both by the blood and by cerebrospinal fluid. Cerebrospinal fluid contents are distinct from the general circulation because of regulation at brain barriers including the choroid plexus, glymphatic system, and blood-brain barrier. In this review, we discuss the overlapping circadian (≈24-hour) rhythms in brain fluid biology and at the brain barriers. Our goal is for the reader to gain both a fundamental understanding of brain barriers alongside an understanding of the interactions between these fluids and the circadian timing system. Ultimately, this review will provide new insight into how alterations in these finely tuned clocks may lead to pathology.
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Affiliation(s)
- Velia S Vizcarra
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Ryann M Fame
- Department of Neurosurgery, Stanford University School of Medicine, Stanford, CA, 94305, USA
| | - Lauren M Hablitz
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
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10
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Pan S, Koleske JP, Koller GM, Halupnik GL, Alli AHO, Koneru S, DeFreitas D, Ramagiri S, Strahle JM. Postnatal meningeal CSF transport is primarily mediated by the arachnoid and pia maters and is not altered after intraventricular hemorrhage-posthemorrhagic hydrocephalus. Fluids Barriers CNS 2024; 21:4. [PMID: 38191402 PMCID: PMC10773070 DOI: 10.1186/s12987-023-00503-7] [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: 08/10/2023] [Accepted: 12/12/2023] [Indexed: 01/10/2024] Open
Abstract
BACKGROUND CSF has long been accepted to circulate throughout the subarachnoid space, which lies between the arachnoid and pia maters of the meninges. How the CSF interacts with the cellular components of the developing postnatal meninges including the dura, arachnoid, and pia of both the meninges at the surface of the brain and the intracranial meninges, prior to its eventual efflux from the cranium and spine, is less understood. Here, we characterize small and large CSF solute distribution patterns along the intracranial and surface meninges in neonatal rodents and compare our findings to meningeal CSF solute distribution in a rodent model of intraventricular hemorrhage-posthemorrhagic hydrocephalus. We also examine CSF solute interactions with the tela choroidea and its pial invaginations into the choroid plexuses of the lateral, third, and fourth ventricles. METHODS 1.9-nm gold nanoparticles, 15-nm gold nanoparticles, or 3 kDa Red Dextran Tetramethylrhodamine constituted in aCSF were infused into the right lateral ventricle of P7 rats to track CSF circulation. 10 min post-1.9-nm gold nanoparticle and Red Dextran Tetramethylrhodamine injection and 4 h post-15-nm gold nanoparticle injection, animals were sacrificed and brains harvested for histologic analysis to identify CSF tracer localization in the cranial and spine meninges and choroid plexus. Spinal dura and leptomeninges (arachnoid and pia) wholemounts were also evaluated. RESULTS There was significantly less CSF tracer distribution in the dura compared to the arachnoid and pia maters in neonatal rodents. Both small and large CSF tracers were transported intracranially to the arachnoid and pia mater of the perimesencephalic cisterns and tela choroidea, but not the falx cerebri. CSF tracers followed a similar distribution pattern in the spinal meninges. In the choroid plexus, there was large CSF tracer distribution in the apical surface of epithelial cells, and small CSF tracer along the basolateral surface. There were no significant differences in tracer intensity in the intracranial meninges of control vs. intraventricular hemorrhage-posthemorrhagic hydrocephalus (PHH) rodents, indicating preserved meningeal transport in the setting of PHH. CONCLUSIONS Differential CSF tracer handling by the meninges suggests that there are distinct roles for CSF handling between the arachnoid-pia and dura maters in the developing brain. Similarly, differences in apical vs. luminal choroid plexus CSF handling may provide insight into particle-size dependent CSF transport at the CSF-choroid plexus border.
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Affiliation(s)
- Shelei Pan
- Department of Neurosurgery, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Joshua P Koleske
- Department of Neurosurgery, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Gretchen M Koller
- Department of Neurosurgery, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Grace L Halupnik
- Department of Neurosurgery, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Abdul-Haq O Alli
- Department of Neurosurgery, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Shriya Koneru
- Department of Neurosurgery, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Dakota DeFreitas
- Department of Neurosurgery, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Sruthi Ramagiri
- Department of Neurosurgery, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA
| | - Jennifer M Strahle
- Department of Neurosurgery, Washington University School of Medicine, Washington University in St. Louis, St. Louis, MO, 63110, USA.
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11
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Umlauf BJ, Frampton G, Cooper A, Greene HF. A novel strategy to increase the therapeutic potency of GBM chemotherapy via altering parenchymal/cerebral spinal fluid clearance rate. J Control Release 2023; 364:195-205. [PMID: 37865172 DOI: 10.1016/j.jconrel.2023.10.024] [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: 07/21/2023] [Revised: 10/04/2023] [Accepted: 10/16/2023] [Indexed: 10/23/2023]
Abstract
Patients with glioblastoma (GBM) face a poor prognosis with a median survival of less than two years. Escalating the dose of chemotherapy is often impossible due to patient comorbidities; thus, we focused on modulating brain clearance as a mechanism to enhance drug accumulation. Given the recently identified interconnectivity between brain parenchymal fluid and cerebral spinal fluid (CSF), we reasoned enhancing drug concentration in the CSF also increases drug concentration in the parenchyma where a GBM resides. To improve drug accumulation in the CSF, we impair the motility of ependymal cell cilia. We identified FDA-approved therapeutics that interact with cilia as a "side effect." Therapeutics that inhibit airway cilia also inhibit ependymal cilia. Multiple cilia-inhibiting drugs, when administered in combination with GBM chemotherapy temozolomide (TMZ), significantly improved the overall survival of mice bearing orthotopic GBM. Combining TMZ with lidocaine results in 100% of animals surviving tumor-free to the study endpoint. This treatment results in a ~ 40-fold increase in brain TMZ levels and is well-tolerated. Mice bearing MGMT methylated, human PDX orthotopic GBM also responded with 100% of animals surviving tumor-free to the study endpoint. Finally, even mice bearing TMZ-resistant, orthotopic GBM responded to the combination treatment with 40% of animals surviving tumor-free to the study endpoint, implying this strategy can sensitize TMZ-resistant GBM. These studies offer a new concept for treating malignant brain tumors by improving the accumulation of TMZ in the CNS. In the future, this regimen may also improve the treatment of additional encephalopathies treated by brain-penetrating therapeutics. SIGNIFICANCE: We exploit the interconnectivity of parenchymal and cerebral spinal fluid to enhance the amount of temozolomide that accumulates in the central nervous system to improve the survival of mice bearing brain tumors.
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Affiliation(s)
- Benjamin J Umlauf
- Department of Neurosurgery, Dell Medical School, The University of Texas at Austin, 1601 Trinity St. Bldg B., Austin, USA; Mulva Clinic for the Neurosciences, The University of Texas at Austin, 1601 Trinity St. Bldg A., Austin, USA.
| | - Gabriel Frampton
- Department of Neurosurgery, Dell Medical School, The University of Texas at Austin, 1601 Trinity St. Bldg B., Austin, USA
| | - Alexis Cooper
- Department of Neurosurgery, Dell Medical School, The University of Texas at Austin, 1601 Trinity St. Bldg B., Austin, USA
| | - Hannah-Faith Greene
- Department of Neurosurgery, Dell Medical School, The University of Texas at Austin, 1601 Trinity St. Bldg B., Austin, USA
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12
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Jiang D, Gou Y, Wei Z, Hou X, Yedavalli V, Lu H. Quantification of T 1 and T 2 of subarachnoid CSF: Implications for water exchange between CSF and brain tissues. Magn Reson Med 2023; 90:2411-2419. [PMID: 37582262 PMCID: PMC10696635 DOI: 10.1002/mrm.29829] [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: 04/14/2023] [Revised: 07/24/2023] [Accepted: 07/27/2023] [Indexed: 08/17/2023]
Abstract
PURPOSE To quantify the T1 and T2 values of CSF in the subarachnoid space (SAS) at 3 T and interpret them in the context of water exchange between CSF and brain tissues. METHODS CSF T1 was measured using inversion recovery, and CSF T2 was assessed using T2 -preparation. T1 and T2 values in the SAS were compared with those in the frontal horns of lateral ventricles, which have less brain-CSF exchange. Phantom experiments were performed to examine whether there were spatial variations in T1 and T2 that were unrelated to brain-CSF exchange. Simulations were conducted to investigate the relationship between the brain-CSF exchange rate and the apparent T1 and T2 values of SAS CSF. RESULTS The CSF T1 and T2 values were 4308.7 ± 146.9 ms and 1885.5 ± 67.9 ms, respectively, in the SAS and were 4454.0 ± 187.9 ms and 2372.9 ± 72.0 ms in the frontal horns. The SAS CSF had shorter T1 (p = 0.006) and T2 (p < 0.0001) than CSF in the frontal horns. Phantom experiments showed negligible (< 6 ms for T1 ; < 1 ms for T2 ) spatial variations in T1 and T2 , suggesting that the T1 and T2 differences between SAS and frontal horns were largely attributed to physiological reasons. Simulations revealed that faster brain-CSF exchange rates lead to shorter apparent T1 and T2 of SAS CSF. However, the experimentally observed T2 difference between SAS and frontal horns was greater than that attributable to typical exchange effect, suggesting that the T2 shortening in SAS may reflect a combined effect of exchange and deoxyhemoglobin susceptibility. CONCLUSION Quantification of SAS CSF relaxation times may be useful to assess the brain-CSF exchange.
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Affiliation(s)
- Dengrong Jiang
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Yifan Gou
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Zhiliang Wei
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Xirui Hou
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Vivek Yedavalli
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Hanzhang Lu
- The Russell H. Morgan Department of Radiology & Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Department of Biomedical Engineering, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
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13
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Bangari DS, Lanigan LG, Cramer SD, Grieves JL, Meisner R, Rogers AB, Galbreath EJ, Bolon B. Toxicologic Neuropathology of Novel Biotherapeutics. Toxicol Pathol 2023; 51:414-431. [PMID: 38380881 DOI: 10.1177/01926233241230542] [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] [Indexed: 02/22/2024]
Abstract
Biotherapeutic modalities such as cell therapies, gene therapies, nucleic acids, and proteins are increasingly investigated as disease-modifying treatments for severe and life-threatening neurodegenerative disorders. Such diverse bio-derived test articles are fraught with unique and often unpredictable biological consequences, while guidance regarding nonclinical experimental design, neuropathology evaluation, and interpretation is often limited. This paper summarizes key messages offered during a half-day continuing education course on toxicologic neuropathology of neuro-targeted biotherapeutics. Topics included fundamental neurobiology concepts, pharmacology, frequent toxicological findings, and their interpretation including adversity decisions. Covered biotherapeutic classes included cell therapies, gene editing and gene therapy vectors, nucleic acids, and proteins. If agents are administered directly into the central nervous system, initial screening using hematoxylin and eosin (H&E)-stained sections of currently recommended neural organs (brain [7 levels], spinal cord [3 levels], and sciatic nerve) may need to expand to include other components (e.g., more brain levels, ganglia, and/or additional nerves) and/or special neurohistological procedures to characterize possible neural effects (e.g., cell type-specific markers for reactive glial cells). Scientists who evaluate the safety of novel biologics will find this paper to be a practical reference for preclinical safety testing and risk assessment.
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Affiliation(s)
| | | | | | | | - René Meisner
- Denali Therapeutics, South San Francisco, California, USA
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Zhu Y, Wang G, Kolluru C, Gu Y, Gao H, Zhang J, Wang Y, Wilson DL, Zhu X, Flask CA, Yu X. Transport pathways and kinetics of cerebrospinal fluid tracers in mouse brain observed by dynamic contrast-enhanced MRI. Sci Rep 2023; 13:13882. [PMID: 37620371 PMCID: PMC10449788 DOI: 10.1038/s41598-023-40896-x] [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: 03/20/2023] [Accepted: 08/17/2023] [Indexed: 08/26/2023] Open
Abstract
Recent studies have suggested the glymphatic system as a key mechanism of waste removal in the brain. Dynamic contrast-enhanced MRI (DCE-MRI) using intracisternally administered contrast agents is a promising tool for assessing glymphatic function in the whole brain. In this study, we evaluated the transport kinetics and distribution of three MRI contrast agents with vastly different molecular sizes in mice. Our results demonstrate that oxygen-17 enriched water (H217O), which has direct access to parenchymal tissues via aquaporin-4 water channels, exhibited significantly faster and more extensive transport compared to the two gadolinium-based contrast agents (Gd-DTPA and GadoSpin). Time-lagged correlation and clustering analyses also revealed different transport pathways for Gd-DTPA and H217O. Furthermore, there were significant differences in transport kinetics of the three contrast agents to the lateral ventricles, reflecting the differences in forces that drive solute transport in the brain. These findings suggest the size-dependent transport pathways and kinetics of intracisternally administered contrast agents and the potential of DCE-MRI for assessing multiple aspects of solute transport in the glymphatic system.
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Affiliation(s)
- Yuran Zhu
- Department of Biomedical Engineering, Case Western Reserve University, Wickenden 430, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Guanhua Wang
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Chaitanya Kolluru
- Department of Biomedical Engineering, Case Western Reserve University, Wickenden 430, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Yuning Gu
- Department of Biomedical Engineering, Case Western Reserve University, Wickenden 430, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Huiyun Gao
- Cardiovascular Research Institute, Case Western Reserve University, Cleveland, OH, USA
- Department of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Jing Zhang
- Department of Biostatistics, Population and Quantitative Health Sciences, Case Western Reserve University, Cleveland, OH, USA
| | - Yunmei Wang
- Cardiovascular Research Institute, Case Western Reserve University, Cleveland, OH, USA
- Department of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - David L Wilson
- Department of Biomedical Engineering, Case Western Reserve University, Wickenden 430, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
- Department of Radiology, Case Western Reserve University, Wickenden 430, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Xiaofeng Zhu
- Department of Biostatistics, Population and Quantitative Health Sciences, Case Western Reserve University, Cleveland, OH, USA
| | - Chris A Flask
- Department of Biomedical Engineering, Case Western Reserve University, Wickenden 430, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
- Department of Radiology, Case Western Reserve University, Wickenden 430, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA
| | - Xin Yu
- Department of Biomedical Engineering, Case Western Reserve University, Wickenden 430, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.
- Department of Radiology, Case Western Reserve University, Wickenden 430, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.
- Department of Physiology and Biophysics, Case Western Reserve University, Wickenden 430, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.
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15
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Pan S, Koleske J, Koller GM, Halupnik GL, Alli AHO, Koneru S, DeFreitas D, Ramagiri U, Strahle JM. Meningeal CSF transport is primarily mediated by the arachnoid and pia maters during development. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.08.10.552826. [PMID: 37645776 PMCID: PMC10461931 DOI: 10.1101/2023.08.10.552826] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 08/31/2023]
Abstract
Background The recent characterization of the glymphatic system and meningeal lymphatics has re-emphasized the role of the meninges in facilitating CSF transport and clearance. Here, we characterize small and large CSF solute distribution patterns along the intracranial and surface meninges in neonatal rodents and compare our findings to a rodent model of intraventricular hemorrhage-posthemorrhagic hydrocephalus. We also examine CSF interactions with the tela choroidea and its pial invaginations into the choroid plexuses of the lateral, third, and fourth ventricles. Methods 1.9-nm gold nanoparticles, 15-nm gold nanoparticles, or 3 kDa Red Dextran Tetramethylrhodamine constituted in aCSF were infused into the right lateral ventricle of P7 rats to track CSF circulation. 10 minutes post-1.9-nm gold nanoparticle and Red Dextran Tetramethylrhodamine injection and 4 hours post-15-nm gold nanoparticle injection, animals were sacrificed and brains harvested for histologic analysis to identify CSF tracer localization in the cranial and spine meninges and choroid plexus. Spinal dura and leptomeninges (arachnoid and pia) wholemounts were also performed. Results There was significantly less CSF tracer distribution in the dura compared to the arachnoid and pia maters in neonatal rodents. Both small and large CSF tracers were transported intracranially to the arachnoid and pia mater of the perimesencephalic cisterns and tela choroidea, but not the dura mater of the falx cerebri. CSF tracers followed a similar distribution pattern in the spinal meninges. In the choroid plexus, there was large CSF tracer distribution in the apical surface of epithelial cells, and small CSF tracer along the basolateral surface. There were no significant differences in tracer intensity in the intracranial meninges of control vs. intraventricular hemorrhage-posthemorrhagic hydrocephalus (PHH) rodents, indicating preserved meningeal transport in the setting of PHH. Conclusions Differential CSF tracer handling by the leptomeninges suggests that there are distinct roles for CSF handling between the arachnoid-pia and dura maters in the developing brain. Similarly, differences in apical vs. luminal choroid plexus CSF handling may provide insight into particle-size dependent CSF transport at the CSF-choroid plexus border.
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16
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Segeroth M, Wachsmuth L, Gagel M, Albers F, Hess A, Faber C. Disentangling the impact of cerebrospinal fluid formation and neuronal activity on solute clearance from the brain. Fluids Barriers CNS 2023; 20:43. [PMID: 37316849 DOI: 10.1186/s12987-023-00443-2] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2022] [Accepted: 05/18/2023] [Indexed: 06/16/2023] Open
Abstract
BACKGROUND Despite recent attention, pathways and mechanisms of fluid transposition in the brain are still a matter of intense discussion and driving forces underlying waste clearance in the brain remain elusive. Consensus exists that net solute transport is a prerequisite for efficient clearance. The individual impact of neuronal activity and cerebrospinal fluid (CSF) formation, which both vary with brain state and anesthesia, remain unclear. METHODS To separate conditions with high and low neuronal activity and high and low CSF formation, different anesthetic regimens in naive rat were established, using Isoflurane (ISO), Medetomidine (MED), acetazolamide or combinations thereof. With dynamic contrast-enhanced MRI, after application of low molecular weight contrast agent (CA) Gadobutrol to cisterna magna, tracer distribution was monitored as surrogate for solute clearance. Simultaneous fiber-based Ca2+-recordings informed about the state of neuronal activity under different anesthetic regimen. T2-weighted MRI and diffusion-weighted MRI (DWI) provided size of subarachnoidal space and aqueductal flow as surrogates for CSF formation. Finally, a pathway and mechanism-independent two-compartment model was introduced to provide a measure of efficiency for solute clearance from the brain. RESULTS Anatomical imaging, DWI and Ca2+-recordings confirmed that conditions with distinct levels of neuronal activity and CSF formation were achieved. A sleep-resembling condition, with reduced neuronal activity and enhanced CSF formation was achieved using ISO+MED and an awake-like condition with high neuronal activity using MED alone. CA distribution in the brain correlated with the rate of CSF formation. The cortical brain state had major influence on tracer diffusion. Under conditions with low neuronal activity, higher diffusivity suggested enlargement of extracellular space, facilitating a deeper permeation of solutes into brain parenchyma. Under conditions with high neuronal activity, diffusion of solutes into parenchyma was hindered and clearance along paravascular pathways facilitated. Exclusively based on the measured time signal curves, the two-compartment model provided net exchange ratios, which were significantly larger for the sleep-resembling condition than for the awake-like condition. CONCLUSIONS Efficiency of solute clearance in brain changes with alterations in both state of neuronal activity and CSF formation. Our clearance pathway and mechanism agnostic kinetic model informs about net solute transport, solely based on the measured time signal curves. This rather simplifying approach largely accords with preclinical and clinical findings.
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Affiliation(s)
- Martin Segeroth
- Translational Research Imaging Center (TRIC), Clinic of Radiology, University of Münster, Albert-Schweitzer-Campus 1, Gebäude A16, 48149, Münster, Germany
- Department of Radiology, University Hospital Basel, Basel, Switzerland
| | - Lydia Wachsmuth
- Translational Research Imaging Center (TRIC), Clinic of Radiology, University of Münster, Albert-Schweitzer-Campus 1, Gebäude A16, 48149, Münster, Germany
| | - Mathias Gagel
- Translational Research Imaging Center (TRIC), Clinic of Radiology, University of Münster, Albert-Schweitzer-Campus 1, Gebäude A16, 48149, Münster, Germany
| | - Franziska Albers
- Translational Research Imaging Center (TRIC), Clinic of Radiology, University of Münster, Albert-Schweitzer-Campus 1, Gebäude A16, 48149, Münster, Germany
| | - Andreas Hess
- Department of Experimental and Clinical Pharmacology and Toxicology, Friedrich-Alexander-University of Erlangen-Nürnberg, Erlangen, Germany
- Institute of Neuroradiology, University Hospital Erlangen, Friedrich-Alexander-University Erlangen-Nürnberg (FAU), Erlangen, Germany
- FAU NeW, Research Center for New Bioactive Compounds, Nikolaus-Fiebiger-Str. 10, 91058, Erlangen, Germany
| | - Cornelius Faber
- Translational Research Imaging Center (TRIC), Clinic of Radiology, University of Münster, Albert-Schweitzer-Campus 1, Gebäude A16, 48149, Münster, Germany.
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Han G, Zhou Y, Zhang K, Jiao B, Hu J, Zhang Y, Wang Z, Lou M, Bai R. Age- and time-of-day dependence of glymphatic function in the human brain measured via two diffusion MRI methods. Front Aging Neurosci 2023; 15:1173221. [PMID: 37284019 PMCID: PMC10239807 DOI: 10.3389/fnagi.2023.1173221] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2023] [Accepted: 05/04/2023] [Indexed: 06/08/2023] Open
Abstract
Advanced age, accompanied by impaired glymphatic function, is a key risk factor for many neurodegenerative diseases. To study age-related differences in the human glymphatic system, we measured the influx and efflux activities of the glymphatic system via two non-invasive diffusion magnetic resonance imaging (MRI) methods, ultra-long echo time and low-b diffusion tensor imaging (DTIlow-b) measuring the subarachnoid space (SAS) flow along the middle cerebral artery and DTI analysis along the perivascular space (DTI-ALPS) along medullary veins in 22 healthy volunteers (aged 21-75 years). We first evaluated the circadian rhythm dependence of the glymphatic activity by repeating the MRI measurements at five time points from 8:00 to 23:00 and found no time-of-day dependence in the awake state under the current sensitivity of MRI measurements. Further test-retest analysis demonstrated high repeatability of both diffusion MRI measurements, suggesting their reliability. Additionally, the influx rate of the glymphatic system was significantly higher in participants aged >45 years than in participants aged 21-38, while the efflux rate was significantly lower in those aged >45 years. The mismatched influx and efflux activities in the glymphatic system might be due to age-related changes in arterial pulsation and aquaporin-4 polarization.
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Affiliation(s)
- Guangxu Han
- Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Shaw Hospital AND Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China
- Key Laboratory of Biomedical Engineering of Education Ministry, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China
| | - Ying Zhou
- Department of Neurology, School of Medicine, The Second Affiliated Hospital of Zhejiang University, Hangzhou, China
| | - Kemeng Zhang
- Department of Neurology, School of Medicine, The Second Affiliated Hospital of Zhejiang University, Hangzhou, China
| | - Bingjie Jiao
- Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Shaw Hospital AND Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China
- Key Laboratory of Biomedical Engineering of Education Ministry, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China
| | - Junwen Hu
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, China
- Clinical Research Center for Neurological Diseases of Zhejiang Province, Hangzhou, China
| | - Yifan Zhang
- Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Shaw Hospital AND Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China
- Key Laboratory of Biomedical Engineering of Education Ministry, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China
| | - Zejun Wang
- Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Shaw Hospital AND Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China
- Key Laboratory of Biomedical Engineering of Education Ministry, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China
| | - Min Lou
- Department of Neurology, School of Medicine, The Second Affiliated Hospital of Zhejiang University, Hangzhou, China
| | - Ruiliang Bai
- Department of Physical Medicine and Rehabilitation of the Affiliated Sir Run Shaw Hospital AND Interdisciplinary Institute of Neuroscience and Technology, School of Medicine, Zhejiang University, Hangzhou, China
- Key Laboratory of Biomedical Engineering of Education Ministry, College of Biomedical Engineering and Instrument Science, Zhejiang University, Hangzhou, China
- MOE Frontier Science Center for Brain Science and Brain-Machine Integration, School of Brain Science and Brain Medicine, Zhejiang University, Hangzhou, China
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Alghanimy A, Martin C, Gallagher L, Holmes WM. The effect of a novel AQP4 facilitator, TGN-073, on glymphatic transport captured by diffusion MRI and DCE-MRI. PLoS One 2023; 18:e0282955. [PMID: 36920936 PMCID: PMC10016657 DOI: 10.1371/journal.pone.0282955] [Citation(s) in RCA: 8] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/29/2022] [Accepted: 02/27/2023] [Indexed: 03/16/2023] Open
Abstract
The glymphatic system is a low resistance pathway, by which cerebrospinal fluid enters the brain parenchyma along perivascular spaces via AQP4 channels. It is hypothesised that the resulting convective flow of the interstitial fluid provides an efficient mechanism for the removal of waste toxins from the brain. Therefore, enhancing AQP4 function might protect against neurodegenerative diseases such as Alzheimer's disease (AD), in which the accumulation of harmful proteins and solutes is a hallmark feature. Here, we test the effect of a putative AQP4 facilitator, TGN-073, on glymphatic transport in a normal rat brain by employing different MRI techniques. Surgical procedures were undertaken to catheterise the cisterna magna, thereby enabling infusion of the MRI tracer. Followed by the intraperitoneal injection of either TGN-073, or the vehicle. Using a paramagnetic contrast agent (Gd-DTPA) as the MRI tracer, dynamic 3D T1 weighted imaging of the glymphatic system was undertaken over two hours. Further, the apparent diffusion coefficient was measured in different brain regions using diffusion-weighted imaging (DWI). While physiological parameters and arterial blood gas analysis were monitored continuously. We found that rats treated with TGN-073 showed the distribution of Gd-DTPA was more extensive and parenchymal uptake was higher compared with the vehicle group. Water diffusivity was increased in the brain of TGN-073 treated group, which indicates greater water flux. Also, MRI showed the glymphatic transport and distribution in the brain is naturally heterogeneous, which is consistent with previous studies. Our results indicate that compounds such as TGN-073 can improve glymphatic function in the brain. Since glymphatic impairment due to AQP4 dysfunction is potentially associated with several neurological disorders such as AD, dementia and traumatic brain injury, enhancing AQP4 functionality might be a promising therapeutic target.
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Affiliation(s)
- Alaa Alghanimy
- Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Science, University of Glasgow, Glasgow, United Kingdom
- Radiological Sciences Department, College of Applied Medical Sciences, King Saud University, Riyadh, Saudi Arabia
| | - Conor Martin
- Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Science, University of Glasgow, Glasgow, United Kingdom
| | - Lindsay Gallagher
- Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Science, University of Glasgow, Glasgow, United Kingdom
| | - William M. Holmes
- Institute of Neuroscience and Psychology, College of Medicine, Veterinary and Life Science, University of Glasgow, Glasgow, United Kingdom
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Zhu Y, Wang G, Kolluru C, Gu Y, Gao H, Zhang J, Wang Y, Wilson DL, Zhu X, Flask CA, Yu X. Transport Pathways and Kinetics of Cerebrospinal Fluid Tracers in Mouse Brain Observed by Dynamic Contrast-Enhanced MRI. RESEARCH SQUARE 2023:rs.3.rs-2544475. [PMID: 36798228 PMCID: PMC9934740 DOI: 10.21203/rs.3.rs-2544475/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Background: Recent studies have suggested the glymphatic system as a solute transport pathway and waste removal mechanism in the brain. Imaging intracisternally administered tracers provides the opportunity of assessing various aspects of the glymphatic function. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) allows the evaluation of both the kinetics and spatial distribution of tracer transport in the whole brain. However, assessing mouse glymphatic function by DCE-MRI has been challenged by the small size of a mouse brain and the limited volume of fluids that can be delivered intracisternally without significantly altering the intracranial pressure. Further, previous studies in rats suggest that assessment of glymphatic function by DCE-MRI is dependent on the molecular size of the contrast agents. Methods: We established and validated an intracisternal infusion protocol in mice that allowed the measurements of the entire time course of contrast agent transport for 2 hours. The transport kinetics and distribution of three MRI contrast agents with drastically different molecular weights (MWs): Gd-DTPA (MW=661.8 Da, n=7), GadoSpin-P (MW=200 kDa, n=6), and oxygen-17 enriched water (H 2 17 O, MW=19 Da, n=7), were investigated. Results: The transport of H 2 17 O was significantly faster and more extensive than the two gadolinium-based contrast agents. Time-lagged correlation analysis and clustering analysis comparing the kinetics of Gd-DTPA and H 2 17 O transport also showed different cluster patterns and lag time between different regions of the brain, suggesting different transport pathways for H 2 17 O because of its direct access to parenchymal tissues via the aquaporin-4 water channels. Further, there were also significant differences in the transport kinetics of the three tracers to the lateral ventricles, which reflects the differences in forces that drive tracer transport in the brain. Conclusions: Comparison of the transport kinetics and distribution of three MRI contrast agents with different molecular sizes showed drastically different transport profiles and clustering patterns, suggesting that the transport pathways and kinetics in the glymphatic system are size-dependent.
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Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Xin Yu
- Case Western Reserve University
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20
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Hopkins K, Price B, Ziogas J, Adamides A, Mangum J. Comparative proteomic analysis of ventricular and cisternal cerebrospinal fluid in haemorrhagic stroke patients. J Clin Neurosci 2023; 107:84-90. [PMID: 36525746 DOI: 10.1016/j.jocn.2022.11.006] [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: 07/20/2022] [Revised: 11/04/2022] [Accepted: 11/10/2022] [Indexed: 12/23/2022]
Abstract
BACKGROUND Analysis of cerebrospinal fluid (CSF) using mass spectrometry is a relatively novel analytical tool, and comparisons of ventricular and cisternal proteomes are yet to be performed. This may have implications for clinical medicine, particularly in demonstrating continuity of the ventricular system with preserved flow in the presence of ventricular blood. Other uses include the identification of novel biomarkers, including for diagnosis of subarachnoid haemorrhage and of aetiology. The primary objective was therefore to characterise and compare the proteomes of ventricular and CSF after haemorrhagic stroke. METHODS Paired CSF samples were prospectively collected from the optico-carotid cistern and the frontal horn of the lateral ventricle at the time of craniotomy and clipping in 8 patients with haemorrhagic stroke. Six patients had an aneurysmal subarachnoid haemorrhage (aSAH) from a ruptured saccular aneurysm, one patient had an aSAH after rupture of a mycotic aneurysm and one patient had a spontaneous intracerebral haemorrhage (IPH) with an adjacent unruptured saccular aneurysm. Samples were processed and proteins identified and quantified using data-dependent liquid chromatography tandem mass spectrometry (DDA LC-MSMS). RESULTS There was no systematic difference between the cisternal and ventricular proteomes. However, blinded principal component analysis (PCA) of the cisternal and ventricular samples separated patients according to pathophysiology. Additionally CSF D-Dimer levels were not detected in the IPH patient but were reliably measured in aSAH patients. CONCLUSIONS Ventricular CSF is representative of cisternal CSF after aSAH. CSF proteomic PCA analysis can distinguish between haemorrhage types. CSF D-dimer levels may represent a novel diagnostic marker for aSAH. Label free DDA LC-MSMS CSF analysis may inform possible biomarkers.
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Affiliation(s)
- Katherine Hopkins
- Department of Biochemistry and Pharmacology, The University of Melbourne, Melbourne, VIC, Australia
| | - Benjamin Price
- Department of Biochemistry and Pharmacology, The University of Melbourne, Melbourne, VIC, Australia; Department of Neurosurgery, The Royal Melbourne Hospital, Melbourne, VIC, Australia.
| | - James Ziogas
- Department of Biochemistry and Pharmacology, The University of Melbourne, Melbourne, VIC, Australia
| | - Alexios Adamides
- Department of Neurosurgery, The Royal Melbourne Hospital, Melbourne, VIC, Australia
| | - Jonathan Mangum
- Department of Biochemistry and Pharmacology, The University of Melbourne, Melbourne, VIC, Australia
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21
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Role of the glymphatic system in idiopathic intracranial hypertension. Clin Neurol Neurosurg 2022; 222:107446. [DOI: 10.1016/j.clineuro.2022.107446] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/08/2022] [Revised: 09/13/2022] [Accepted: 09/14/2022] [Indexed: 11/23/2022]
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22
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He XZ, Li X, Li ZH, Meng JC, Mao RT, Zhang XK, Zhang RT, Huang HL, Gui Q, Xu GY, Wang LH. High-resolution 3D demonstration of regional heterogeneity in the glymphatic system. J Cereb Blood Flow Metab 2022; 42:2017-2031. [PMID: 35786032 PMCID: PMC9580176 DOI: 10.1177/0271678x221109997] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
Accumulating evidence indicates that the glymphatic system has a critical role in maintaining brain homeostasis. However, the detailed anatomy of the glymphatic pathway is not well understood, mostly due to a lack of high spatial resolution 3D visualization. In this study, a fluorescence micro-optical sectioning tomography (fMOST) was used to characterize the glymphatic architecture in the mouse brain. At 30 and 120 min after intracisternal infusion with fluorescent dextran (Dex-3), lectin was injected to stain the cerebral vasculature. Using fMOST, a high-resolution 3D dataset of the brain-wide distribution of Dex-3 was acquired. Combined with fluorescence microscopy and microplate array, the heterogeneous glymphatic flow and the preferential irrigated regions were identified. These cerebral regions containing large-caliber penetrating arteries and/or adjacent to the subarachnoid space had more robust CSF flow compared to other regions. Moreover, the major glymphatic vessels for CSF influx and fluid efflux in the entire brain were shown in 3D. This study demonstrates the regional heterogeneity in the glymphatic system and provides an anatomical resource for further investigation of the glymphatic function.
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Affiliation(s)
- Xu-Zhong He
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, Suzhou, PR China
| | - Xin Li
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, Suzhou, PR China
| | - Zhen-Hua Li
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, Suzhou, PR China
| | - Jing-Cai Meng
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, Suzhou, PR China
| | - Rui-Ting Mao
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, Suzhou, PR China
| | - Xue-Ke Zhang
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, Suzhou, PR China
| | - Rong-Ting Zhang
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, Suzhou, PR China
| | - Huai-Liang Huang
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, Suzhou, PR China
| | - Qian Gui
- Department of Neurology, Suzhou Municipal Hospital, Suzhou, PR China
| | - Guang-Yin Xu
- Institute of Neuroscience, Soochow University, Suzhou, PR China
| | - Lin-Hui Wang
- Department of Physiology and Neurobiology, Suzhou Medical College of Soochow University, Suzhou, PR China
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23
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Greiner T, Manzhula K, Baumann L, Kaddatz H, Runge J, Keiler J, Kipp M, Joost S. Morphology of the murine choroid plexus: Attachment regions and spatial relation to the subarachnoid space. Front Neuroanat 2022; 16:1046017. [DOI: 10.3389/fnana.2022.1046017] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/16/2022] [Accepted: 10/11/2022] [Indexed: 11/13/2022] Open
Abstract
The choroid plexus has recently been identified as a possible migration route for peripheral immune cells into the central nervous system. For future investigation of this route, profound knowledge of the morphology of the murine choroid plexus is a prerequisite. We here present a detailed morphological description of the murine choroid plexus, its attachment regions as well as its spatial relation to the subarachnoid space. We used micro-computed tomography of immersion-contrasted fixated brains to generate three-dimensional models of the ventricle system and the choroid plexus and aligned micro-computed tomography-based sections with histological paraffin-embedded sections after immunohistochemical labeling of the basal lamina and choroid plexus epithelium marker proteins (laminin and aquaporin 1). The murine choroid plexus is located in all four ventricles and is attached to the brain parenchyma in narrow attachment regions with a specific morphology in each ventricle. While in the lateral and fourth ventricle, the attachment site is formed by thin tissue bridges, the choroid plexus attachment in the third ventricle has a more complex V-like shape. In all ventricles, the choroid plexus is in close spatial relationship with the subarachnoid space that extends from the brain surface along physiologic openings toward the choroid plexus. In summary, we here provide a description of the morphology of the murine ventricle system and choroid plexus, the attachment regions of the choroid plexus and its connection to the subarachnoid space, as well as a three-dimensional model of the ventricles, the choroid plexus, and the subarachnoid space to facilitate a spatial understanding of these complex structures.
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24
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Bohr T, Hjorth PG, Holst SC, Hrabětová S, Kiviniemi V, Lilius T, Lundgaard I, Mardal KA, Martens EA, Mori Y, Nägerl UV, Nicholson C, Tannenbaum A, Thomas JH, Tithof J, Benveniste H, Iliff JJ, Kelley DH, Nedergaard M. The glymphatic system: Current understanding and modeling. iScience 2022; 25:104987. [PMID: 36093063 PMCID: PMC9460186 DOI: 10.1016/j.isci.2022.104987] [Citation(s) in RCA: 94] [Impact Index Per Article: 47.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
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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Affiliation(s)
- Tomas Bohr
- Department of Physics, Technical University of Denmark, 2800 Kgs. Lyngby, Denmark
| | - Poul G. Hjorth
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Richard Petersens Plads, 2800 Kgs. Lyngby, Denmark
| | - Sebastian C. Holst
- Neuroscience and Rare Diseases Discovery and Translational Area, Roche Pharmaceutical Research and Early Development, Roche Innovation Center Basel, Grenzacherstrasse 124, 4070 Basel, Switzerland
| | - Sabina Hrabětová
- Department of Cell Biology and The Robert Furchgott Center for Neural and Behavioral Science, State University of New York Downstate Medical Center, Brooklyn, NY, USA
| | - Vesa Kiviniemi
- Oulu Functional NeuroImaging, Department of Diagnostic Radiology, MRC, Oulu University Hospital, Oulu, Finland
- Medical Imaging, Physics and Technology, the Faculty of Medicine, University of Oulu, Oulu, Finland
| | - Tuomas Lilius
- Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Department of Emergency Medicine and Services, Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Iben Lundgaard
- Department of Experimental Medical Science, Lund University, Lund, Sweden
- Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden
| | - Kent-Andre Mardal
- Department of Mathematics, University of Oslo, Oslo, Norway
- Simula Research Laboratory, Department of Numerical Analysis and Scientific Computing, Oslo, Norway
| | | | - Yuki Mori
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - U. Valentin Nägerl
- Instítut Interdisciplinaire de Neurosciences, Université de Bordeaux / CNRS UMR 5297, Centre Broca Nouvelle-Aquitaine, 146 rue Léo Saignat, CS 61292 Case 130, 33076 Bordeaux Cedex France
| | - Charles Nicholson
- Department of Neuroscience and Physiology, New York University Grossman School of Medicine, New York, NY, USA
- Department of Cell Biology, SUNY Downstate Health Sciences University, Brooklyn, NY, USA
| | - Allen Tannenbaum
- Departments of Computer Science/ Applied Mathematics and Statistics, Stony Brook University, Stony Brook, NY, USA
| | - John H. Thomas
- Department of Mechanical Engineering, University of Rochester, Rochester, 14627 NY, USA
| | - Jeffrey Tithof
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, USA
| | - Helene Benveniste
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT, USA
- Department of Biomedical Engineering, Yale School of Medicine, New Haven, CT, USA
| | - Jeffrey J. Iliff
- VISN 20 Mental Illness Research, Education and Clinical Center, VA Puget Sound Health Care System, Seattle, WA, USA
- Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA, USA
- Department of Neurology, University of Washington School of Medicine, Seattle, WA, USA
| | - Douglas H. Kelley
- Department of Mechanical Engineering, University of Rochester, Rochester, 14627 NY, USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, 14642 NY, USA
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25
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Assessing pulsatile waveforms of paravascular cerebrospinal fluid dynamics using dynamic diffusion-weighted imaging (dDWI). Neuroimage 2022; 260:119464. [PMID: 35835339 PMCID: PMC9434732 DOI: 10.1016/j.neuroimage.2022.119464] [Citation(s) in RCA: 15] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Revised: 07/08/2022] [Accepted: 07/10/2022] [Indexed: 11/25/2022] Open
Abstract
Cerebrospinal fluid (CSF) in the paravascular spaces of the surface arteries (sPVS) is a vital pathway in brain waste clearance. Arterial pulsations may be the driving force of the paravascular flow, but its pulsatile pattern remains poorly characterized, and no clinically practical method for measuring its dynamics in the human brain is available. In this work, we introduce an imaging and quantification framework for in-vivo non-invasive assessment of pulsatile fluid dynamics in the sPVS. It used dynamic Diffusion-Weighted Imaging (dDWI) at a lower b-values of 150s/mm2 and retrospective gating to detect the slow flow of CSF while suppressing the fast flow of adjacent arterial blood. The waveform of CSF flow over a cardiac cycle was revealed by synchronizing the measurements with the heartbeat. A data-driven approach was developed to identify sPVS and allow automatic quantification of the whole-brain fluid waveforms. We applied dDWI to twenty-five participants aged 18–82 y/o. Results demonstrated that the fluid waveforms across the brain showed an explicit cardiac-cycle dependency, in good agreement with the vascular pumping hypothesis. Furthermore, the shape of the CSF waveforms closely resembled the pressure waveforms of the artery wall, suggesting that CSF dynamics is tightly related to artery wall mechanics. Finally, the CSF waveforms in aging participants revealed a strong age effect, with a significantly wider systolic peak observed in the older relative to younger participants. The peak widening may be associated with compromised vascular compliance and vessel wall stiffening in the older brain. Overall, the results demonstrate the feasibility, reproducibility, and sensitivity of dDWI for detecting sPVS fluid dynamics of the human brain. Our preliminary data suggest age-related alterations of the paravascular pumping. With an acquisition time of under six minutes, dDWI can be readily applied to study fluid dynamics in normal physiological conditions and cerebrovascular/neurodegenerative diseases.
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26
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Boster KAS, Tithof J, Cook DD, Thomas JH, Kelley DH. Sensitivity analysis on a network model of glymphatic flow. J R Soc Interface 2022; 19:20220257. [PMID: 35642425 PMCID: PMC9156905 DOI: 10.1098/rsif.2022.0257] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2022] [Accepted: 05/05/2022] [Indexed: 12/24/2022] Open
Abstract
Intracranial cerebrospinal and interstitial fluid (ISF) flow and solute transport have important clinical implications, but limited in vivo access to the brain interior leaves gaping holes in human understanding of the nature of these neurophysiological phenomena. Models can address some gaps, but only insofar as model inputs are accurate. We perform a sensitivity analysis using a Monte Carlo approach on a lumped-parameter network model of cerebrospinal and ISF in perivascular and extracellular spaces in the murine brain. We place bounds on model predictions given the uncertainty in input parameters. Péclet numbers for transport in penetrating perivascular spaces (PVSs) and within the parenchyma are separated by at least two orders of magnitude. Low permeability in penetrating PVSs requires unrealistically large driving pressure and/or results in poor perfusion and are deemed unlikely. The model is most sensitive to the permeability of penetrating PVSs, a parameter whose value is largely unknown, highlighting an important direction for future experiments. Until the value of the permeability of penetrating PVSs is more accurately measured, the uncertainty of any model that includes flow in penetrating PVSs is so large that absolute numbers have little meaning and practical application is limited.
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Affiliation(s)
- Kimberly A. S. Boster
- Department of Mechanical Engineering, University of Rochester, Rochester, NY 14627, USA
| | - Jeffrey Tithof
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
| | - Douglas D. Cook
- Department of Mechanical Engineering, Brigham Young University, Provo, UT 84602, USA
| | - John H. Thomas
- Department of Mechanical Engineering, University of Rochester, Rochester, NY 14627, USA
| | - Douglas H. Kelley
- Department of Mechanical Engineering, University of Rochester, Rochester, NY 14627, USA
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27
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Padmakumar S, Kulkarni P, Ferris CF, Bleier BS, Amiji MM. Traumatic brain injury and the development of parkinsonism: Understanding pathophysiology, animal models, and therapeutic targets. Biomed Pharmacother 2022; 149:112812. [PMID: 35290887 PMCID: PMC9050934 DOI: 10.1016/j.biopha.2022.112812] [Citation(s) in RCA: 10] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/18/2022] [Revised: 03/06/2022] [Accepted: 03/08/2022] [Indexed: 02/06/2023] Open
Abstract
The clinical translation of therapeutic approaches to combat debilitating neurodegenerative conditions, such as Parkinson's disease (PD), remains as an urgent unmet challenge. The strong molecular association between the pathogenesis of traumatic brain injury (TBI) and the development of parkinsonism in humans has been well established. Therefore, a lot of ongoing research aims to investigate this pathology overlap in-depth, to exploit the common targets of TBI and PD for development of more effective and long-term treatment strategies. This review article intends to provide a detailed background on TBI pathophysiology and its established overlap with PD with an additional emphasis on the recent findings about their effect on perivascular clearance. Although, the traditional animal models of TBI and PD are still being considered, there is a huge focus on the development of combinatory hybrid animal models coupling concussion with the pre-established PD models for a better recapitulation of the human context of PD pathogenesis. Lastly, the therapeutic targets for TBI and PD, and the contemporary research involving exosomes, DNA vaccines, miRNA, gene therapy and gene editing for the development of potential candidates are discussed, along with the recent development of lesser invasive and promising central nervous system (CNS) drug delivery strategies.
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Affiliation(s)
- Smrithi Padmakumar
- Department of Pharmaceutical Sciences, School of Pharmacy and Department of Chemical Engineering, College of Engineering, Northeastern University, Boston, MA, United States of America
| | - Praveen Kulkarni
- Center for Translational NeuroImaging, Northeastern University, Boston, MA, United States of America
| | - Craig F Ferris
- Center for Translational NeuroImaging, Northeastern University, Boston, MA, United States of America
| | - Benjamin S Bleier
- Massachusetts Eye and Ear Infirmary, Harvard Medical School, Boston, MA, United States of America
| | - Mansoor M Amiji
- Department of Pharmaceutical Sciences, School of Pharmacy and Department of Chemical Engineering, College of Engineering, Northeastern University, Boston, MA, United States of America.
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28
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Hladky SB, Barrand MA. The glymphatic hypothesis: the theory and the evidence. Fluids Barriers CNS 2022; 19:9. [PMID: 35115036 PMCID: PMC8815211 DOI: 10.1186/s12987-021-00282-z] [Citation(s) in RCA: 87] [Impact Index Per Article: 43.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 10/15/2021] [Indexed: 12/13/2022] Open
Abstract
The glymphatic hypothesis proposes a mechanism for extravascular transport into and out of the brain of hydrophilic solutes unable to cross the blood-brain barrier. It suggests that there is a circulation of fluid carrying solutes inwards via periarterial routes, through the interstitium and outwards via perivenous routes. This review critically analyses the evidence surrounding the mechanisms involved in each of these stages. There is good evidence that both influx and efflux of solutes occur along periarterial routes but no evidence that the principal route of outflow is perivenous. Furthermore, periarterial inflow of fluid is unlikely to be adequate to provide the outflow that would be needed to account for solute efflux. A tenet of the hypothesis is that flow sweeps solutes through the parenchyma. However, the velocity of any possible circulatory flow within the interstitium is too small compared to diffusion to provide effective solute movement. By comparison the earlier classical hypothesis describing extravascular transport proposed fluid entry into the parenchyma across the blood-brain barrier, solute movements within the parenchyma by diffusion, and solute efflux partly by diffusion near brain surfaces and partly carried by flow along "preferred routes" including perivascular spaces, white matter tracts and subependymal spaces. It did not suggest fluid entry via periarterial routes. Evidence is still incomplete concerning the routes and fate of solutes leaving the brain. A large proportion of the solutes eliminated from the parenchyma go to lymph nodes before reaching blood but the proportions delivered directly to lymph or indirectly via CSF which then enters lymph are as yet unclear. In addition, still not understood is why and how the absence of AQP4 which is normally highly expressed on glial endfeet lining periarterial and perivenous routes reduces rates of solute elimination from the parenchyma and of solute delivery to it from remote sites of injection. Neither the glymphatic hypothesis nor the earlier classical hypothesis adequately explain how solutes and fluid move into, through and out of the brain parenchyma. Features of a more complete description are discussed. All aspects of extravascular transport require further study.
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Affiliation(s)
- Stephen B. Hladky
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD UK
| | - Margery A. Barrand
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD UK
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29
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Xu D, Zhou J, Mei H, Li H, Sun W, Xu H. Impediment of Cerebrospinal Fluid Drainage Through Glymphatic System in Glioma. Front Oncol 2022; 11:790821. [PMID: 35083148 PMCID: PMC8784869 DOI: 10.3389/fonc.2021.790821] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/07/2021] [Accepted: 12/15/2021] [Indexed: 11/29/2022] Open
Abstract
Background Cerebrospinal fluid (CSF) plays an important role in maintaining tissue homeostasis in the central nervous system. In 2012, the new CSF outflow pathway, “the glymphatic system,” was discovered. The glymphatic system mediates CSF and interstitial fluid exchange through the perivascular pathway, which eliminates harmful solutes in the brain parenchyma. In recent studies, the importance of the glymphatic system has been demonstrated in healthy and neurodegenerative disease brains. However, there is limited research on the function of the CSF in brain tumors. Intracranial hypertension caused by glioma can affect CSF drainage, which impacts the delivery of chemotherapy drugs via intrathecal injection. This study focused on changes in the glymphatic system and the role of aquaporin 4 (AQP4) in glymphatic transport in glioma. Methods In glioma-bearing rats, the effect of tracer infusion on the intracranial pressure (ICP) was evaluated using an ICP microsensor. In vivo magnetic resonance imaging and ex vivo bright field were used to monitor CSF tracer distribution after cisterna magna injection. AQP4 expression was quantitatively detected, and AQP4 in the astrocytes around the vessels was observed using immunofluorescence. Results The ICP of the tumor group was higher than that of the control group and the infusion rate of 2 µl/min did not affect ICP. In vivo and ex vivo imaging showed that the circulation of CSF tracers was significantly impaired in the tumor. High-power confocal microscopy revealed that, in the tumor, the surrounding of AQP4 by Evans Blue was decreased. In both tumor and contralateral areas, data indicated that the number of cluster designation 34 (CD34+) alpha-smooth muscle actin (α-SMA−) veins were more than that of CD34+α-SMA+ arteries. Moreover, in the tumor area, AQP4 in the astrocytes around the vessels was decreased. Conclusions These findings indicate that the para-arterial influx of subarachnoid CSF is limited in glioma, especially in those with reduced levels of the fundamental protein AQP4. Our results provide evidence toward a potential new treatment method for glioma in the future.
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Affiliation(s)
- Dan Xu
- Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Jie Zhou
- Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Hao Mei
- Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Huan Li
- Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Wenbo Sun
- Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, China
| | - Haibo Xu
- Department of Radiology, Zhongnan Hospital of Wuhan University, Wuhan University, Wuhan, China
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30
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Gómez-de Frutos MC, García-Suárez I, Laso-García F, Diekhorst L, Otero-Ortega L, Alonso de Leciñana M, Fuentes B, Gutiérrez-Fernández M, Díez-Tejedor E, Ruíz-Ares G. B-Mode Ultrasound, a Reliable Tool for Monitoring Experimental Intracerebral Hemorrhage. Front Neurol 2022; 12:771402. [PMID: 35002926 PMCID: PMC8733327 DOI: 10.3389/fneur.2021.771402] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/06/2021] [Accepted: 11/29/2021] [Indexed: 11/25/2022] Open
Abstract
Background: Magnetic resonance imaging (MRI) is currently used for the study of intracerebral hemorrhage (ICH) in animal models. However, ultrasound is an inexpensive, non-invasive and rapid technique that could facilitate the diagnosis and follow-up of ICH. This study aimed to evaluate the feasibility and reliability of B-mode ultrasound as an alternative tool for in vivo monitoring of ICH volume and brain structure displacement in an animal model. Methods: A total of 31 male and female Sprague-Dawley rats were subjected to an ICH model using collagenase-IV in the striatum following stereotaxic references. The animals were randomly allocated into 3 groups: healthy (n = 10), sham (n = 10) and ICH (n = 11). B-mode ultrasound studies with a 13-MHz probe were performed pre-ICH and at 5 h, 48 h, 4 d and 1 mo post-ICH for the assessment of ICH volume and displacement of brain structures, considering the distance between the subarachnoid cisterns and the dura mater. The same variables were studied by MRI at 48 h and 1 mo post-ICH. Results: Both imaging techniques showed excellent correlation in measuring ICH volume at 48 h (r = 0.905) and good at 1 mo (r = 0.656). An excellent correlation was also observed in the measured distance between the subarachnoid cisterns and the dura mater at 1 mo between B-mode ultrasound and MRI, on both the ipsilateral (r = 0.870) and contralateral (r = 0.906) sides of the lesion. Conclusion: B-mode ultrasound imaging appears to be a reliable tool for in vivo assessment of ICH volume and displacement of brain structures in animal models.
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Affiliation(s)
- Mari Carmen Gómez-de Frutos
- Neurological Sciences and Cerebrovascular Research Laboratory, Department of Neurology and Stroke Center, Neuroscience Area of IdiPAZ Health Research Institute, La Paz University Hospital, Universidad Autónoma de Madrid, Madrid, Spain
| | - Iván García-Suárez
- Neurological Sciences and Cerebrovascular Research Laboratory, Department of Neurology and Stroke Center, Neuroscience Area of IdiPAZ Health Research Institute, La Paz University Hospital, Universidad Autónoma de Madrid, Madrid, Spain.,Department of Emergency Service, San Agustín Hospital, University of San Agustin, Asturias, Spain
| | - Fernando Laso-García
- Neurological Sciences and Cerebrovascular Research Laboratory, Department of Neurology and Stroke Center, Neuroscience Area of IdiPAZ Health Research Institute, La Paz University Hospital, Universidad Autónoma de Madrid, Madrid, Spain
| | - Luke Diekhorst
- Neurological Sciences and Cerebrovascular Research Laboratory, Department of Neurology and Stroke Center, Neuroscience Area of IdiPAZ Health Research Institute, La Paz University Hospital, Universidad Autónoma de Madrid, Madrid, Spain
| | - Laura Otero-Ortega
- Neurological Sciences and Cerebrovascular Research Laboratory, Department of Neurology and Stroke Center, Neuroscience Area of IdiPAZ Health Research Institute, La Paz University Hospital, Universidad Autónoma de Madrid, Madrid, Spain
| | - María Alonso de Leciñana
- Neurological Sciences and Cerebrovascular Research Laboratory, Department of Neurology and Stroke Center, Neuroscience Area of IdiPAZ Health Research Institute, La Paz University Hospital, Universidad Autónoma de Madrid, Madrid, Spain
| | - Blanca Fuentes
- Neurological Sciences and Cerebrovascular Research Laboratory, Department of Neurology and Stroke Center, Neuroscience Area of IdiPAZ Health Research Institute, La Paz University Hospital, Universidad Autónoma de Madrid, Madrid, Spain
| | - María Gutiérrez-Fernández
- Neurological Sciences and Cerebrovascular Research Laboratory, Department of Neurology and Stroke Center, Neuroscience Area of IdiPAZ Health Research Institute, La Paz University Hospital, Universidad Autónoma de Madrid, Madrid, Spain
| | - Exuperio Díez-Tejedor
- Neurological Sciences and Cerebrovascular Research Laboratory, Department of Neurology and Stroke Center, Neuroscience Area of IdiPAZ Health Research Institute, La Paz University Hospital, Universidad Autónoma de Madrid, Madrid, Spain
| | - Gerardo Ruíz-Ares
- Neurological Sciences and Cerebrovascular Research Laboratory, Department of Neurology and Stroke Center, Neuroscience Area of IdiPAZ Health Research Institute, La Paz University Hospital, Universidad Autónoma de Madrid, Madrid, Spain
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Ray LA, Pike M, Simon M, Iliff JJ, Heys JJ. Quantitative analysis of macroscopic solute transport in the murine brain. Fluids Barriers CNS 2021; 18:55. [PMID: 34876169 PMCID: PMC8650464 DOI: 10.1186/s12987-021-00290-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 11/21/2021] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Understanding molecular transport in the brain is critical to care and prevention of neurological disease and injury. A key question is whether transport occurs primarily by diffusion, or also by convection or dispersion. Dynamic contrast-enhanced (DCE-MRI) experiments have long reported solute transport in the brain that appears to be faster than diffusion alone, but this transport rate has not been quantified to a physically relevant value that can be compared to known diffusive rates of tracers. METHODS In this work, DCE-MRI experimental data is analyzed using subject-specific finite-element models to quantify transport in different anatomical regions across the whole mouse brain. The set of regional effective diffusivities ([Formula: see text]), a transport parameter combining all mechanisms of transport, that best represent the experimental data are determined and compared to apparent diffusivity ([Formula: see text]), the known rate of diffusion through brain tissue, to draw conclusions about dominant transport mechanisms in each region. RESULTS In the perivascular regions of major arteries, [Formula: see text] for gadoteridol (550 Da) was over 10,000 times greater than [Formula: see text]. In the brain tissue, constituting interstitial space and the perivascular space of smaller blood vessels, [Formula: see text] was 10-25 times greater than [Formula: see text]. CONCLUSIONS The analysis concludes that convection is present throughout the brain. Convection is dominant in the perivascular space of major surface and branching arteries (Pe > 1000) and significant to large molecules (> 1 kDa) in the combined interstitial space and perivascular space of smaller vessels (not resolved by DCE-MRI). Importantly, this work supports perivascular convection along penetrating blood vessels.
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Affiliation(s)
- Lori A Ray
- Department of Chemical and Biological Engineering, Montana State University, Bozeman, USA
| | - Martin Pike
- Advanced Imaging Research Center, Oregon Health and Sciences University, Portland, USA
| | - Matthew Simon
- Department of Anesthesiology and Perioperative Medicine, Oregon Health and Science University, Portland, USA
- Neuroscience Graduate Program, Oregon Health and Science University, Portland, USA
- Denali Therapeutics, San Francisco, USA
| | - Jeffrey J Iliff
- VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), VA Puget Sound Health Care System, Seattle, USA
- Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, USA
- Department of Neurology, University of Washington School of Medicine, Seattle, USA
| | - Jeffrey J Heys
- Department of Chemical and Biological Engineering, Montana State University, Bozeman, USA.
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van Veluw SJ, Perosa V. The Perivascular Space Race: Understanding Their Role in Brain Clearance. Neurology 2021; 98:95-96. [PMID: 34810242 DOI: 10.1212/wnl.0000000000013105] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022] Open
Affiliation(s)
- Susanne J van Veluw
- Department of Neurology, Massachusetts General Hospital / Harvard Medical School, Boston, MA, USA
| | - Valentina Perosa
- Department of Neurology, Massachusetts General Hospital / Harvard Medical School, Boston, MA, USA
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Cai X, Harding IC, Sadaka AH, Colarusso B, Kulkarni P, Ebong E, Qiao J, O'Hare NR, Ferris CF. Mild repetitive head impacts alter perivascular flow in the midbrain dopaminergic system in awake rats. Brain Commun 2021; 3:fcab265. [PMID: 34806002 PMCID: PMC8600963 DOI: 10.1093/braincomms/fcab265] [Citation(s) in RCA: 7] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/06/2021] [Revised: 08/02/2021] [Accepted: 08/10/2021] [Indexed: 11/24/2022] Open
Abstract
Head injury is a known risk factor for Parkinson's disease. Disruption in the perivascular clearance of metabolic waste and unwanted proteins is thought to be a contributing factor to disease progression. We hypothesized that repetitive mild head impacts, without evidence of structural brain damage, would increase microgliosis and AQP4 expression and depolarization and alter perivascular flow in the midbrain dopaminergic system. Adult male rats were subjected to sham, or two mild head impacts separated by 48 h. Three weeks later, fully awake rats were imaged using dynamic, contrast-enhanced MRI to follow the distribution of intraventricular gadobenate dimeglumine contrast agent. Images were registered to and analysed using a 3D MRI rat atlas providing site-specific data on 171 different brain areas. Following imaging, rats were tested for cognitive function using the Barnes maze assay. Histological analyses of tyrosine hydroxylase, microglia activation and AQP4 expression and polarization were performed on a parallel cohort of head impacted rats at 20 days post insult to coordinate with the time of imaging. There was no change in the global flux of contrast agent between sham and head impacted rats. The midbrain dopaminergic system showed a significant decrease in the influx of contrast agent as compared to sham controls together with a significant increase in microgliosis, AQP4 expression and depolarization. There were no deficits in cognitive function. The histology showed a significant level of neuroinflammation in the midbrain dopaminergic system 3 weeks post mild repetitive head impact but no loss in tyrosine hydroxylase. MRI revealed no structural brain damage emphasizing the potential serious consequences of mild head impacts on sustained brain neuroinflammation in this area critical to the pathophysiology of Parkinson's.
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Affiliation(s)
- Xuezhu Cai
- Department of Psychology, Center for Translational NeuroImaging, Northeastern University, Boston, MA 02115, USA
| | - Ian C Harding
- Department of Bioengineering, Northeastern University, Boston, MA 02115, USA
| | - Aymen H Sadaka
- Department of Psychology, Center for Translational NeuroImaging, Northeastern University, Boston, MA 02115, USA
| | - Bradley Colarusso
- Department of Psychology, Center for Translational NeuroImaging, Northeastern University, Boston, MA 02115, USA
| | - Praveen Kulkarni
- Department of Psychology, Center for Translational NeuroImaging, Northeastern University, Boston, MA 02115, USA
| | - Eno Ebong
- Department of Bioengineering, Northeastern University, Boston, MA 02115, USA
- Department of Chemical Engineering, Northeastern University, Boston, MA 02115, USA
- Department of Neuroscience, Albert Einstein College of Medicine, New York, NY 10461, USA
| | - Ju Qiao
- Department of Psychology, Center for Translational NeuroImaging, Northeastern University, Boston, MA 02115, USA
| | - Nick R O'Hare
- Department of Bioengineering, Northeastern University, Boston, MA 02115, USA
| | - Craig F Ferris
- Department of Psychology, Center for Translational NeuroImaging, Northeastern University, Boston, MA 02115, USA
- Department of Psychology, Northeastern University, Boston, MA 02115, USA
- Department of Pharmaceutical Sciences, Northeastern University, Boston, MA 02115, USA
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34
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Klostranec JM, Vucevic D, Bhatia KD, Kortman HGJ, Krings T, Murphy KP, terBrugge KG, Mikulis DJ. Current Concepts in Intracranial Interstitial Fluid Transport and the Glymphatic System: Part I-Anatomy and Physiology. Radiology 2021; 301:502-514. [PMID: 34665028 DOI: 10.1148/radiol.2021202043] [Citation(s) in RCA: 28] [Impact Index Per Article: 9.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/20/2022]
Abstract
Normal physiologic function of organs requires a circulation of interstitial fluid to deliver nutrients and clear cellular waste products. Lymphatic vessels serve as collectors of this fluid in most organs; however, these vessels are absent in the central nervous system. How the central nervous system maintains tight control of extracellular conditions has been a fundamental question in neuroscience until recent discovery of the glial-lymphatic, or glymphatic, system was made this past decade. Networks of paravascular channels surrounding pial and parenchymal arteries and veins were found that extend into the walls of capillaries to allow fluid transport and exchange between the interstitial and cerebrospinal fluid spaces. The currently understood anatomy and physiology of the glymphatic system is reviewed, with the paravascular space presented as an intrinsic component of healthy pial and parenchymal cerebral blood vessels. Glymphatic system behavior in animal models of health and disease, and its enhanced function during sleep, are discussed. The evolving understanding of glymphatic system characteristics is then used to provide a current interpretation of its physiology that can be helpful for radiologists when interpreting neuroimaging investigations.
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Affiliation(s)
- Jesse M Klostranec
- From the Montreal Neurologic Institute and Hospital, Department of Diagnostic and Interventional Neuroradiology, McGill University Health Centre, 3801 Rue University, Montréal, QC, Canada H3A 2B4 (J.M.K.); Department of Medical Imaging, University of Toronto, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Division of Neuroradiology, Toronto Western Hospital, University Health Network, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Centre Hospitalier de l'Université de Montreal (CHUM), Department of Radiology, Service of Neuroradiology, l'Université de Montreal, Montréal, Canada (J.M.K.); Department of Materials Science & Engineering, Faculty of Applied Science & Engineering, University of Toronto, Toronto, Canada (D.V.); Department of Medical Imaging, Sydney Children's Hospitals Network, Westmead, Australia (K.D.B.); and Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Canada (T.K., K.G.t.B.)
| | - Diana Vucevic
- From the Montreal Neurologic Institute and Hospital, Department of Diagnostic and Interventional Neuroradiology, McGill University Health Centre, 3801 Rue University, Montréal, QC, Canada H3A 2B4 (J.M.K.); Department of Medical Imaging, University of Toronto, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Division of Neuroradiology, Toronto Western Hospital, University Health Network, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Centre Hospitalier de l'Université de Montreal (CHUM), Department of Radiology, Service of Neuroradiology, l'Université de Montreal, Montréal, Canada (J.M.K.); Department of Materials Science & Engineering, Faculty of Applied Science & Engineering, University of Toronto, Toronto, Canada (D.V.); Department of Medical Imaging, Sydney Children's Hospitals Network, Westmead, Australia (K.D.B.); and Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Canada (T.K., K.G.t.B.)
| | - Kartik D Bhatia
- From the Montreal Neurologic Institute and Hospital, Department of Diagnostic and Interventional Neuroradiology, McGill University Health Centre, 3801 Rue University, Montréal, QC, Canada H3A 2B4 (J.M.K.); Department of Medical Imaging, University of Toronto, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Division of Neuroradiology, Toronto Western Hospital, University Health Network, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Centre Hospitalier de l'Université de Montreal (CHUM), Department of Radiology, Service of Neuroradiology, l'Université de Montreal, Montréal, Canada (J.M.K.); Department of Materials Science & Engineering, Faculty of Applied Science & Engineering, University of Toronto, Toronto, Canada (D.V.); Department of Medical Imaging, Sydney Children's Hospitals Network, Westmead, Australia (K.D.B.); and Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Canada (T.K., K.G.t.B.)
| | - Hans G J Kortman
- From the Montreal Neurologic Institute and Hospital, Department of Diagnostic and Interventional Neuroradiology, McGill University Health Centre, 3801 Rue University, Montréal, QC, Canada H3A 2B4 (J.M.K.); Department of Medical Imaging, University of Toronto, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Division of Neuroradiology, Toronto Western Hospital, University Health Network, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Centre Hospitalier de l'Université de Montreal (CHUM), Department of Radiology, Service of Neuroradiology, l'Université de Montreal, Montréal, Canada (J.M.K.); Department of Materials Science & Engineering, Faculty of Applied Science & Engineering, University of Toronto, Toronto, Canada (D.V.); Department of Medical Imaging, Sydney Children's Hospitals Network, Westmead, Australia (K.D.B.); and Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Canada (T.K., K.G.t.B.)
| | - Timo Krings
- From the Montreal Neurologic Institute and Hospital, Department of Diagnostic and Interventional Neuroradiology, McGill University Health Centre, 3801 Rue University, Montréal, QC, Canada H3A 2B4 (J.M.K.); Department of Medical Imaging, University of Toronto, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Division of Neuroradiology, Toronto Western Hospital, University Health Network, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Centre Hospitalier de l'Université de Montreal (CHUM), Department of Radiology, Service of Neuroradiology, l'Université de Montreal, Montréal, Canada (J.M.K.); Department of Materials Science & Engineering, Faculty of Applied Science & Engineering, University of Toronto, Toronto, Canada (D.V.); Department of Medical Imaging, Sydney Children's Hospitals Network, Westmead, Australia (K.D.B.); and Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Canada (T.K., K.G.t.B.)
| | - Kieran P Murphy
- From the Montreal Neurologic Institute and Hospital, Department of Diagnostic and Interventional Neuroradiology, McGill University Health Centre, 3801 Rue University, Montréal, QC, Canada H3A 2B4 (J.M.K.); Department of Medical Imaging, University of Toronto, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Division of Neuroradiology, Toronto Western Hospital, University Health Network, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Centre Hospitalier de l'Université de Montreal (CHUM), Department of Radiology, Service of Neuroradiology, l'Université de Montreal, Montréal, Canada (J.M.K.); Department of Materials Science & Engineering, Faculty of Applied Science & Engineering, University of Toronto, Toronto, Canada (D.V.); Department of Medical Imaging, Sydney Children's Hospitals Network, Westmead, Australia (K.D.B.); and Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Canada (T.K., K.G.t.B.)
| | - Karel G terBrugge
- From the Montreal Neurologic Institute and Hospital, Department of Diagnostic and Interventional Neuroradiology, McGill University Health Centre, 3801 Rue University, Montréal, QC, Canada H3A 2B4 (J.M.K.); Department of Medical Imaging, University of Toronto, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Division of Neuroradiology, Toronto Western Hospital, University Health Network, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Centre Hospitalier de l'Université de Montreal (CHUM), Department of Radiology, Service of Neuroradiology, l'Université de Montreal, Montréal, Canada (J.M.K.); Department of Materials Science & Engineering, Faculty of Applied Science & Engineering, University of Toronto, Toronto, Canada (D.V.); Department of Medical Imaging, Sydney Children's Hospitals Network, Westmead, Australia (K.D.B.); and Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Canada (T.K., K.G.t.B.)
| | - David J Mikulis
- From the Montreal Neurologic Institute and Hospital, Department of Diagnostic and Interventional Neuroradiology, McGill University Health Centre, 3801 Rue University, Montréal, QC, Canada H3A 2B4 (J.M.K.); Department of Medical Imaging, University of Toronto, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Division of Neuroradiology, Toronto Western Hospital, University Health Network, Toronto, Canada (J.M.K., D.V., K.D.B., H.G.J.K., T.K., K.P.M., K.G.t.B., D.J.M.); Centre Hospitalier de l'Université de Montreal (CHUM), Department of Radiology, Service of Neuroradiology, l'Université de Montreal, Montréal, Canada (J.M.K.); Department of Materials Science & Engineering, Faculty of Applied Science & Engineering, University of Toronto, Toronto, Canada (D.V.); Department of Medical Imaging, Sydney Children's Hospitals Network, Westmead, Australia (K.D.B.); and Division of Neurosurgery, Department of Surgery, University of Toronto, Toronto, Canada (T.K., K.G.t.B.)
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Eltanahy AM, Koluib YA, Gonzales A. Pericytes: Intrinsic Transportation Engineers of the CNS Microcirculation. Front Physiol 2021; 12:719701. [PMID: 34497540 PMCID: PMC8421025 DOI: 10.3389/fphys.2021.719701] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/02/2021] [Accepted: 07/29/2021] [Indexed: 12/15/2022] Open
Abstract
Pericytes in the brain are candidate regulators of microcirculatory blood flow because they are strategically positioned along the microvasculature, contain contractile proteins, respond rapidly to neuronal activation, and synchronize microvascular dynamics and neurovascular coupling within the capillary network. Analyses of mice with defects in pericyte generation demonstrate that pericytes are necessary for the formation of the blood-brain barrier, development of the glymphatic system, immune homeostasis, and white matter function. The development, identity, specialization, and progeny of different subtypes of pericytes, however, remain unclear. Pericytes perform brain-wide 'transportation engineering' functions in the capillary network, instructing, integrating, and coordinating signals within the cellular communicome in the neurovascular unit to efficiently distribute oxygen and nutrients ('goods and services') throughout the microvasculature ('transportation grid'). In this review, we identify emerging challenges in pericyte biology and shed light on potential pericyte-targeted therapeutic strategies.
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Affiliation(s)
- Ahmed M. Eltanahy
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, NV, United States
| | - Yara A. Koluib
- Tanta University Hospitals, Faculty of Medicine, Tanta University, Tanta, Egypt
| | - Albert Gonzales
- Department of Physiology and Cell Biology, School of Medicine, University of Nevada, Reno, NV, United States
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36
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Brain solute transport is more rapid in periarterial than perivenous spaces. Sci Rep 2021; 11:16085. [PMID: 34373476 PMCID: PMC8352970 DOI: 10.1038/s41598-021-95306-x] [Citation(s) in RCA: 11] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2021] [Accepted: 07/23/2021] [Indexed: 11/13/2022] Open
Abstract
Fluid flow in perivascular spaces is recognized as a key component underlying brain transport and clearance. An important open question is how and to what extent differences in vessel type or geometry affect perivascular fluid flow and transport. Using computational modelling in both idealized and image-based geometries, we study and compare fluid flow and solute transport in pial (surface) periarterial and perivenous spaces. Our findings demonstrate that differences in geometry between arterial and venous pial perivascular spaces (PVSs) lead to higher net CSF flow, more rapid tracer transport and earlier arrival times of injected tracers in periarterial spaces compared to perivenous spaces. These findings can explain the experimentally observed rapid appearance of tracers around arteries, and the delayed appearance around veins without the need of a circulation through the parenchyma, but rather by direct transport along the PVSs.
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37
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Ferris CF. Rethinking the Conditions and Mechanism for Glymphatic Clearance. Front Neurosci 2021; 15:624690. [PMID: 33897347 PMCID: PMC8060639 DOI: 10.3389/fnins.2021.624690] [Citation(s) in RCA: 13] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2020] [Accepted: 03/10/2021] [Indexed: 11/13/2022] Open
Abstract
Critical studies that form the foundation of the glymphatic system and the clearance of metabolic by-products of unwanted proteins from the brain are reviewed. Concerns are raised about studying glymphatic flow in anesthetized animals and making assumptions about the whole brain based upon data collected from a cranial window on the cortex. A new model is proposed arguing that the flow of cerebral spinal fluid and parenchymal clearance in the perivascular system of unwanted proteins is regulated by circadian changes in brain temperature and blood flow at the level of the microvasculature.
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Affiliation(s)
- Craig F Ferris
- Department Psychology and Pharmaceutical Sciences, Center for Translational Neuroimaging, Northeastern University, Boston, MA, United States
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38
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Eide PK, Valnes LM, Lindstrøm EK, Mardal KA, Ringstad G. Direction and magnitude of cerebrospinal fluid flow vary substantially across central nervous system diseases. Fluids Barriers CNS 2021; 18:16. [PMID: 33794929 PMCID: PMC8017867 DOI: 10.1186/s12987-021-00251-6] [Citation(s) in RCA: 23] [Impact Index Per Article: 7.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/21/2020] [Accepted: 03/20/2021] [Indexed: 11/10/2022] Open
Abstract
Background Several central nervous system diseases are associated with disturbed cerebrospinal fluid (CSF) flow patterns and have typically been characterized in vivo by phase-contrast magnetic resonance imaging (MRI). This technique is, however, limited by its applicability in space and time. Phase-contrast MRI has yet to be compared directly with CSF tracer enhanced imaging, which can be considered gold standard for assessing long-term CSF flow dynamics within the intracranial compartment. Methods Here, we studied patients with various CSF disorders and compared MRI biomarkers of CSF space anatomy and phase-contrast MRI at level of the aqueduct and cranio-cervical junction with dynamic intrathecal contrast-enhanced MRI using the contrast agent gadobutrol as CSF tracer. Tracer enrichment of cerebral ventricles was graded 0–4 by visual assessment. An intracranial pressure (ICP) score was used as surrogate marker of intracranial compliance. Results The study included 94 patients and disclosed marked variation of CSF flow measures across disease categories. The grade of supra-aqueductal reflux of tracer varied, with strong reflux (grades 3–4) in half of patients. Ventricular tracer reflux correlated with stroke volume and aqueductal CSF pressure gradient. CSF flow in the cerebral aqueduct was retrograde (from 4th to 3rd ventricle) in one third of patients, with estimated CSF net flow volume about 1.0 L/24 h. In the cranio-cervical junction, net flow was cranially directed in 78% patients, with estimated CSF net flow volume about 4.7 L/24 h. Conclusions The present observations provide in vivo quantitative evidence for substantial variation in direction and magnitude of CSF flow, with re-direction of aqueductal flow in communicating hydrocephalus, and significant extra-cranial CSF production. The grading of ventricular reflux of tracer shows promise as a clinical useful method to assess CSF flow pattern disturbances in patients. Graphic abstract ![]()
Supplementary Information The online version contains supplementary material available at 10.1186/s12987-021-00251-6.
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Affiliation(s)
- Per Kristian Eide
- Deptartment of Neurosurgery, Oslo University Hospital-Rikshospitalet, Nydalen, PB 4950, 0424, Oslo, Norway. .,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
| | - Lars Magnus Valnes
- Deptartment of Neurosurgery, Oslo University Hospital-Rikshospitalet, Nydalen, PB 4950, 0424, Oslo, Norway
| | - Erika Kristina Lindstrøm
- Department of Mathematics, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway.,Institute for Cancer Genetics and Informatics, Oslo University Hospital, Oslo, Norway
| | - Kent-Andre Mardal
- Department of Mathematics, Faculty of Mathematics and Natural Sciences, University of Oslo, Oslo, Norway.,Department of Numerical Analysis and Scientific Computing, Simula Research Laboratory, Oslo, Norway
| | - Geir Ringstad
- Department. of Radiology, Oslo University Hospital-Rikshospitalet, Oslo, Norway
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39
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Naessens DMP, Dobbe JGG, de Vos J, VanBavel E, Bakker ENTP. Mapping Solute Clearance From the Mouse Hippocampus Using a 3D Imaging Cryomicrotome. Front Neurosci 2021; 15:631325. [PMID: 33867918 PMCID: PMC8044999 DOI: 10.3389/fnins.2021.631325] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2020] [Accepted: 03/02/2021] [Indexed: 11/13/2022] Open
Abstract
The hippocampus is susceptible to protein aggregation in neurodegenerative diseases such as Alzheimer's disease. This protein accumulation is partially attributed to an impaired clearance; however, the removal pathways for fluids and waste products are not fully understood. The aim of this study was therefore to map the clearance pathways from the mouse brain. A mixture of two fluorescently labeled tracers with different molecular weights was infused into the hippocampus. A small subset of mice (n = 3) was sacrificed directly after an infusion period of 10 min to determine dispersion of the tracer due to the infusion, while another group was sacrificed after spreading of the tracers for an additional 80 min (n = 7). Upon sacrifice, mice were frozen and sectioned as a whole by the use of a custom-built automated imaging cryomicrotome. Detailed 3D reconstructions were created to map the tracer spreading. We observed that tracers distributed over the hippocampus and entered adjacent brain structures, such as the cortex and cerebroventricular system. An important clearance pathway was found along the ventral part of the hippocampus and its bordering interpeduncular cistern. From there, tracers left the brain via the subarachnoid spaces in the directions of both the nose and the spinal cord. Although both tracers followed the same route, the small tracer distributed further, implying a major role for diffusion in addition to convection. Taken together, these results reveal an important clearance pathway of solutes from the hippocampus.
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Affiliation(s)
- Daphne M P Naessens
- Department of Biomedical Engineering and Physics, Amsterdam UMC, Amsterdam Neuroscience, University of Amsterdam, Amsterdam, Netherlands
| | - Johannes G G Dobbe
- Department of Biomedical Engineering and Physics, Amsterdam UMC, Amsterdam Movement Sciences, University of Amsterdam, Amsterdam, Netherlands
| | - Judith de Vos
- Department of Biomedical Engineering and Physics, Amsterdam UMC, Amsterdam Neuroscience, University of Amsterdam, Amsterdam, Netherlands
| | - Ed VanBavel
- Department of Biomedical Engineering and Physics, Amsterdam UMC, Amsterdam Neuroscience, University of Amsterdam, Amsterdam, Netherlands
| | - Erik N T P Bakker
- Department of Biomedical Engineering and Physics, Amsterdam UMC, Amsterdam Neuroscience, University of Amsterdam, Amsterdam, Netherlands
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40
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Gómez-de Frutos MC, García-Suárez I, Laso-García F, Diekhorst L, Otero-Ortega L, Alonso-López E, Díez-Tejedor E, Gutiérrez-Fernández M, Ruiz-Ares G. Identification of brain structures and blood vessels by conventional ultrasound in rats. J Neurosci Methods 2020; 346:108935. [PMID: 32916202 DOI: 10.1016/j.jneumeth.2020.108935] [Citation(s) in RCA: 6] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/21/2020] [Revised: 07/16/2020] [Accepted: 09/02/2020] [Indexed: 11/15/2022]
Abstract
BACKGROUND Ultrasound is a safe, non-invasive and affordable imaging technique for the visualization of internal structures and the measurement of blood velocity using Doppler imaging. However, despite all these advantages, no study has identified the structures of the rat brain using conventional ultrasound. METHODS A 13 MHz high frequency transducer was used to identify brain structures in the rat. The enlargement of the transcranial window was performed gradually using the ultrasound directly on the skin of the animal, then against the skull, then through a delimited craniotomy and finally through a complete craniotomy. RESULTS Our results showed that ultrasound allowed the identification of cerebral ventricles and subarachnoid cisterns, as well as the analysis of real-time monitoring of cerebral blood flow in the main brain arteries of the rat. COMPARISON WITH EXISTING METHODS Ultrasound is a tool with the potential to identify brain structures and blood vessels. In contrast to MRI, transcranial ultrasound is a fast, non-invasive, well tolerated and low-cost method and can be done at the bedside. CONCLUSION In the present study, we described an atlas of the main brain structures as well as the main vasculature in the rat using ultrasound. This technique could be applied in animal models of various neurological diseases.
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Affiliation(s)
- Mari Carmen Gómez-de Frutos
- Neurological Sciences and Cerebrovascular Research Laboratory, Department of Neurology and Stroke Center, La Paz University Hospital, Neuroscience Area of IdiPAZ Health Research Institute, Universidad Autónoma de Madrid, Madrid, Spain
| | - Iván García-Suárez
- Emergency Service, San Agustín University Hospital, Avilés, Asturias, Spain
| | - Fernando Laso-García
- Neurological Sciences and Cerebrovascular Research Laboratory, Department of Neurology and Stroke Center, La Paz University Hospital, Neuroscience Area of IdiPAZ Health Research Institute, Universidad Autónoma de Madrid, Madrid, Spain
| | - Luke Diekhorst
- Neurological Sciences and Cerebrovascular Research Laboratory, Department of Neurology and Stroke Center, La Paz University Hospital, Neuroscience Area of IdiPAZ Health Research Institute, Universidad Autónoma de Madrid, Madrid, Spain
| | - Laura Otero-Ortega
- Neurological Sciences and Cerebrovascular Research Laboratory, Department of Neurology and Stroke Center, La Paz University Hospital, Neuroscience Area of IdiPAZ Health Research Institute, Universidad Autónoma de Madrid, Madrid, Spain
| | - Elisa Alonso-López
- Neurological Sciences and Cerebrovascular Research Laboratory, Department of Neurology and Stroke Center, La Paz University Hospital, Neuroscience Area of IdiPAZ Health Research Institute, Universidad Autónoma de Madrid, Madrid, Spain
| | - Exuperio Díez-Tejedor
- Neurological Sciences and Cerebrovascular Research Laboratory, Department of Neurology and Stroke Center, La Paz University Hospital, Neuroscience Area of IdiPAZ Health Research Institute, Universidad Autónoma de Madrid, Madrid, Spain
| | - María Gutiérrez-Fernández
- Neurological Sciences and Cerebrovascular Research Laboratory, Department of Neurology and Stroke Center, La Paz University Hospital, Neuroscience Area of IdiPAZ Health Research Institute, Universidad Autónoma de Madrid, Madrid, Spain.
| | - Gerardo Ruiz-Ares
- Neurological Sciences and Cerebrovascular Research Laboratory, Department of Neurology and Stroke Center, La Paz University Hospital, Neuroscience Area of IdiPAZ Health Research Institute, Universidad Autónoma de Madrid, Madrid, Spain.
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41
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Vardakis JC, Chou D, Guo L, Ventikos Y. Exploring neurodegenerative disorders using a novel integrated model of cerebral transport: Initial results. Proc Inst Mech Eng H 2020; 234:1223-1234. [PMID: 33078663 PMCID: PMC7675777 DOI: 10.1177/0954411920964630] [Citation(s) in RCA: 7] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
The neurovascular unit (NVU) underlines the complex and symbiotic relationship between brain cells and the cerebral vasculature, and dictates the need to consider both neurodegenerative and cerebrovascular diseases under the same mechanistic umbrella. Importantly, unlike peripheral organs, the brain was thought not to contain a dedicated lymphatics system. The glymphatic system concept (a portmanteau of glia and lymphatic) has further emphasized the importance of cerebrospinal fluid transport and emphasized its role as a mechanism for waste removal from the central nervous system. In this work, we outline a novel multiporoelastic solver which is embedded within a high precision, subject specific workflow that allows for the co-existence of a multitude of interconnected compartments with varying properties (multiple-network poroelastic theory, or MPET), that allow for the physiologically accurate representation of perfused brain tissue. This novel numerical template is based on a six-compartment MPET system (6-MPET) and is implemented through an in-house finite element code. The latter utilises the specificity of a high throughput imaging pipeline (which has been extended to incorporate the regional variation of mechanical properties) and blood flow variability model developed as part of the VPH-DARE@IT research platform. To exemplify the capability of this large-scale consolidated pipeline, a cognitively healthy subject is used to acquire novel, biomechanistically inspired biomarkers relating to primary and derivative variables of the 6-MPET system. These biomarkers are shown to capture the sophisticated nature of the NVU and the glymphatic system, paving the way for a potential route in deconvoluting the complexity associated with the likely interdependence of neurodegenerative and cerebrovascular diseases. The present study is the first, to the best of our knowledge, that casts and implements the 6-MPET equations in a 3D anatomically accurate brain geometry.
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Affiliation(s)
- John C Vardakis
- CISTIB Centre for Computational Imaging and Simulation Technologies in Biomedicine, School of Computing, University of Leeds, Leeds, UK
| | - Dean Chou
- Department of Biomedical Engineering, National Cheng Kung University, Tainan City, Taiwan
| | - Liwei Guo
- Department of Mechanical Engineering, University College London, London, UK
| | - Yiannis Ventikos
- Department of Mechanical Engineering, University College London, London, UK
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42
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Eide PK, Valnes LM, Pripp AH, Mardal KA, Ringstad G. Delayed clearance of cerebrospinal fluid tracer from choroid plexus in idiopathic normal pressure hydrocephalus. J Cereb Blood Flow Metab 2020; 40:1849-1858. [PMID: 31495299 PMCID: PMC7446558 DOI: 10.1177/0271678x19874790] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 01/16/2023]
Abstract
Impaired clearance of amyloid-β from choroid plexus is one proposed mechanism behind amyloid deposition in Alzheimer's disease. The present study examined whether clearance from choroid plexus of a cerebrospinal fluid tracer, serving as a surrogate marker of a metabolic waste product, is altered in idiopathic normal pressure hydrocephalus (iNPH), one sub-type of dementia. In a prospective observational study of close to healthy individuals (reference cohort; REF) and individuals with iNPH, we performed standardized T1-weighted magnetic resonance imaging scans before and through 24 h after intrathecal administration of a cerebrospinal fluid tracer (the magnetic resonance imaging contrast agent gadobutrol). Changes in normalized T1 signal within the choroid plexus and cerebrospinal fluid of lateral ventricles were quantified using FreeSurfer. The normalized T1 signal increased to maximum within choroid plexus and cerebrospinal fluid of lateral ventricles 6-9 h after intrathecal gadobutrol in both the REF and iNPH cohorts (enrichment phase). Peak difference in normalized T1 signals between REF and iNPH individuals occurred after 24 h (clearance phase). The results gave evidence for gadobutrol resorption from cerebrospinal fluid by choroid plexus, but with delay in iNPH patients. Whether choroid plexus has a role in iNPH pathogenesis in terms of delayed clearance of amyloid-β remains to be shown.
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Affiliation(s)
- Per Kristian Eide
- Department of Neurosurgery, Oslo University Hospital - Rikshospitalet, Oslo, Norway.,Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway
| | | | - Are Hugo Pripp
- Oslo Centre of Biostatistics and Epidemiology, Research Support Services, Oslo University Hospital, Oslo, Norway
| | - Kent-Andre Mardal
- Department of Mathematics, University of Oslo, Oslo, Norway.,Center for Biomedical Computing, Simula Research Laboratory, Lysaker, Norway
| | - Geir Ringstad
- Faculty of Medicine, Institute of Clinical Medicine, University of Oslo, Oslo, Norway.,Division of Radiology and Nuclear Medicine, Department of Radiology, Oslo University Hospital - Rikshospitalet, Oslo, Norway
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43
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Kedarasetti RT, Turner KL, Echagarruga C, Gluckman BJ, Drew PJ, Costanzo F. Functional hyperemia drives fluid exchange in the paravascular space. Fluids Barriers CNS 2020; 17:52. [PMID: 32819402 PMCID: PMC7441569 DOI: 10.1186/s12987-020-00214-3] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/15/2020] [Accepted: 08/09/2020] [Indexed: 12/20/2022] Open
Abstract
The brain lacks a conventional lymphatic system to remove metabolic waste. It has been proposed that directional fluid movement through the arteriolar paravascular space (PVS) promotes metabolite clearance. We performed simulations to examine if arteriolar pulsations and dilations can drive directional CSF flow in the PVS and found that arteriolar wall movements do not drive directional CSF flow. We propose an alternative method of metabolite clearance from the PVS, namely fluid exchange between the PVS and the subarachnoid space (SAS). In simulations with compliant brain tissue, arteriolar pulsations did not drive appreciable fluid exchange between the PVS and the SAS. However, when the arteriole dilated, as seen during functional hyperemia, there was a marked exchange of fluid. Simulations suggest that functional hyperemia may serve to increase metabolite clearance from the PVS. We measured blood vessels and brain tissue displacement simultaneously in awake, head-fixed mice using two-photon microscopy. These measurements showed that brain deforms in response to pressure changes in PVS, consistent with our simulations. Our results show that the deformability of the brain tissue needs to be accounted for when studying fluid flow and metabolite transport.
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Affiliation(s)
- Ravi Teja Kedarasetti
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA
| | - Kevin L Turner
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Christina Echagarruga
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Bruce J Gluckman
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA
- Department of Neurosurgery, The Pennsylvania State University, University Park, PA, USA
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA
| | - Patrick J Drew
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA.
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA.
- Department of Neurosurgery, The Pennsylvania State University, University Park, PA, USA.
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA.
| | - Francesco Costanzo
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, USA.
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, USA.
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, USA.
- Department of Mathematics, The Pennsylvania State University, University Park, PA, USA.
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44
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Harrison IF, Ismail O, Machhada A, Colgan N, Ohene Y, Nahavandi P, Ahmed Z, Fisher A, Meftah S, Murray TK, Ottersen OP, Nagelhus EA, O’Neill MJ, Wells JA, Lythgoe MF. Impaired glymphatic function and clearance of tau in an Alzheimer's disease model. Brain 2020; 143:2576-2593. [PMID: 32705145 PMCID: PMC7447521 DOI: 10.1093/brain/awaa179] [Citation(s) in RCA: 239] [Impact Index Per Article: 59.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/15/2019] [Revised: 03/28/2020] [Accepted: 04/13/2020] [Indexed: 01/09/2023] Open
Abstract
The glymphatic system, that is aquaporin 4 (AQP4) facilitated exchange of CSF with interstitial fluid (ISF), may provide a clearance pathway for protein species such as amyloid-β and tau, which accumulate in the brain in Alzheimer's disease. Further, tau protein transference via the extracellular space, the compartment that is cleared by the glymphatic pathway, allows for its neuron-to-neuron propagation, and the regional progression of tauopathy in the disorder. The glymphatic system therefore represents an exciting new target for Alzheimer's disease. Here we aim to understand the involvement of glymphatic CSF-ISF exchange in tau pathology. First, we demonstrate impaired CSF-ISF exchange and AQP4 polarization in a mouse model of tauopathy, suggesting that this clearance pathway may have the potential to exacerbate or even induce pathogenic accumulation of tau. Subsequently, we establish the central role of AQP4 in the glymphatic clearance of tau from the brain; showing marked impaired glymphatic CSF-ISF exchange and tau protein clearance using the novel AQP4 inhibitor, TGN-020. As such, we show that this system presents as a novel druggable target for the treatment of Alzheimer's disease, and possibly other neurodegenerative diseases alike.
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Affiliation(s)
- Ian F Harrison
- UCL Centre for Advanced Biomedical Imaging, Department of Imaging, Division of Medicine, University College London, London, UK
| | - Ozama Ismail
- UCL Centre for Advanced Biomedical Imaging, Department of Imaging, Division of Medicine, University College London, London, UK
| | - Asif Machhada
- UCL Centre for Advanced Biomedical Imaging, Department of Imaging, Division of Medicine, University College London, London, UK
- Department of Neuroscience, Physiology and Pharmacology, University College London, London, UK
| | - Niall Colgan
- UCL Centre for Advanced Biomedical Imaging, Department of Imaging, Division of Medicine, University College London, London, UK
- School of Physics, National University of Ireland Galway, Ireland
| | - Yolanda Ohene
- UCL Centre for Advanced Biomedical Imaging, Department of Imaging, Division of Medicine, University College London, London, UK
| | - Payam Nahavandi
- UCL Centre for Advanced Biomedical Imaging, Department of Imaging, Division of Medicine, University College London, London, UK
| | - Zeshan Ahmed
- Eli Lilly and Company, Erl Wood Manor, Windlesham, Surrey, UK
| | - Alice Fisher
- Eli Lilly and Company, Erl Wood Manor, Windlesham, Surrey, UK
| | - Soraya Meftah
- Eli Lilly and Company, Erl Wood Manor, Windlesham, Surrey, UK
| | - Tracey K Murray
- Eli Lilly and Company, Erl Wood Manor, Windlesham, Surrey, UK
| | - Ole P Ottersen
- Office of the President, Karolinska Institutet, Stockholm, Sweden
| | - Erlend A Nagelhus
- Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | | | - Jack A Wells
- UCL Centre for Advanced Biomedical Imaging, Department of Imaging, Division of Medicine, University College London, London, UK
| | - Mark F Lythgoe
- UCL Centre for Advanced Biomedical Imaging, Department of Imaging, Division of Medicine, University College London, London, UK
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45
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Kedarasetti RT, Drew PJ, Costanzo F. Arterial pulsations drive oscillatory flow of CSF but not directional pumping. Sci Rep 2020; 10:10102. [PMID: 32572120 PMCID: PMC7308311 DOI: 10.1038/s41598-020-66887-w] [Citation(s) in RCA: 49] [Impact Index Per Article: 12.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/13/2020] [Accepted: 05/28/2020] [Indexed: 01/05/2023] Open
Abstract
The brain lacks a traditional lymphatic system for metabolite clearance. The existence of a "glymphatic system" where metabolites are removed from the brain's extracellular space by convective exchange between interstitial fluid (ISF) and cerebrospinal fluid (CSF) along the paravascular spaces (PVS) around cerebral blood vessels has been controversial. While recent work has shown clear evidence of directional flow of CSF in the PVS in anesthetized mice, the driving force for the observed fluid flow remains elusive. The heartbeat-driven peristaltic pulsation of arteries has been proposed as a probable driver of directed CSF flow. In this study, we use rigorous fluid dynamic simulations to provide a physical interpretation for peristaltic pumping of fluids. Our simulations match the experimental results and show that arterial pulsations only drive oscillatory motion of CSF in the PVS. The observed directional CSF flow can be explained by naturally occurring and/or experimenter-generated pressure differences.
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Affiliation(s)
- Ravi Teja Kedarasetti
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, United States
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, United States
| | - Patrick J Drew
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, United States
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, United States
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, United States
- Department of Neurosurgery, The Pennsylvania State University, University Park, PA, United States
| | - Francesco Costanzo
- Department of Engineering Science and Mechanics, The Pennsylvania State University, University Park, PA, United States.
- Center for Neural Engineering, The Pennsylvania State University, University Park, PA, United States.
- Department of Biomedical Engineering, The Pennsylvania State University, University Park, PA, United States.
- Department of Mathematics, The Pennsylvania State University, University Park, PA, United States.
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46
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Saboori P. Subarachnoid space trabeculae architecture. Clin Anat 2020; 34:40-50. [PMID: 32519396 DOI: 10.1002/ca.23635] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/18/2019] [Revised: 05/08/2020] [Accepted: 05/29/2020] [Indexed: 11/08/2022]
Abstract
INTRODUCTION The motion of the brain relative to the skull is influenced by the architecture of the subarachnoid space (SAS), and in particular, by the arachnoid trabeculae. In previous studies of these structures, specific shapes were identified. However, the work presented here shows much finer detail of the SAS geometries using SEM and TEM. MATERIALS AND METHODS These images were acquired by maintaining the SAS structure of a rat using glutaraldehyde formaldehyde to strengthen the tissues via crosslinking with the biological proteins. RESULTS The results showed the detailed shape of five dominant arachnoid trabeculae structures: single strands, branched strands, tree like shapes, sheets, and trabecular networks. Each of these architectures would provide a different response when exposed to a tensile load and would provide different levels of resistance to the flow of the cerebrospinal fluid (CSF) within the SAS. CONCLUSION This very detailed level of geometric information will therefore allow more accurate finite element models of the SAS to be developed.
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Affiliation(s)
- Parisa Saboori
- Department of Mechanical Engineering, Manhattan College, New York, New York, USA
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47
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Kaur J, Davoodi-Bojd E, Fahmy LM, Zhang L, Ding G, Hu J, Zhang Z, Chopp M, Jiang Q. Magnetic Resonance Imaging and Modeling of the Glymphatic System. Diagnostics (Basel) 2020; 10:diagnostics10060344. [PMID: 32471025 PMCID: PMC7344900 DOI: 10.3390/diagnostics10060344] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/22/2020] [Accepted: 05/25/2020] [Indexed: 12/20/2022] Open
Abstract
The glymphatic system is a newly discovered waste drainage pathway in the brain; it plays an important role in many neurological diseases. Ongoing research utilizing various cerebrospinal fluid tracer infusions, either directly or indirectly into the brain parenchyma, is investigating clearance pathways by using distinct imaging techniques. In the present review, we discuss the role of the glymphatic system in various neurological diseases and efflux pathways of brain waste clearance based on current evidence and controversies. We mainly focus on new magnetic resonance imaging (MRI) modeling techniques, along with traditional computational modeling, for a better understanding of the glymphatic system function. Future sophisticated modeling techniques hold the potential to generate quantitative maps for glymphatic system parameters that could contribute to the diagnosis, monitoring, and prognosis of neurological diseases. The non-invasive nature of MRI may provide a safe and effective way to translate glymphatic system measurements from bench-to-bedside.
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Affiliation(s)
- Jasleen Kaur
- Department of Neurology, Henry Ford Health System, Detroit, MI 48202, USA; (J.K.); (E.D.-B.); (L.M.F.); (L.Z.); (G.D.); (Z.Z.); (M.C.)
- Department of Physics, Oakland University, Rochester, MI 48309, USA
| | - Esmaeil Davoodi-Bojd
- Department of Neurology, Henry Ford Health System, Detroit, MI 48202, USA; (J.K.); (E.D.-B.); (L.M.F.); (L.Z.); (G.D.); (Z.Z.); (M.C.)
- Department of Radiology, Henry Ford Health System, Detroit, MI 48202, USA
| | - Lara M Fahmy
- Department of Neurology, Henry Ford Health System, Detroit, MI 48202, USA; (J.K.); (E.D.-B.); (L.M.F.); (L.Z.); (G.D.); (Z.Z.); (M.C.)
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University, Detroit, MI 48201, USA
| | - Li Zhang
- Department of Neurology, Henry Ford Health System, Detroit, MI 48202, USA; (J.K.); (E.D.-B.); (L.M.F.); (L.Z.); (G.D.); (Z.Z.); (M.C.)
| | - Guangliang Ding
- Department of Neurology, Henry Ford Health System, Detroit, MI 48202, USA; (J.K.); (E.D.-B.); (L.M.F.); (L.Z.); (G.D.); (Z.Z.); (M.C.)
| | - Jiani Hu
- Department of Radiology, Wayne State University, Detroit, MI 48201, USA;
| | - Zhenggang Zhang
- Department of Neurology, Henry Ford Health System, Detroit, MI 48202, USA; (J.K.); (E.D.-B.); (L.M.F.); (L.Z.); (G.D.); (Z.Z.); (M.C.)
| | - Michael Chopp
- Department of Neurology, Henry Ford Health System, Detroit, MI 48202, USA; (J.K.); (E.D.-B.); (L.M.F.); (L.Z.); (G.D.); (Z.Z.); (M.C.)
- Department of Physics, Oakland University, Rochester, MI 48309, USA
| | - Quan Jiang
- Department of Neurology, Henry Ford Health System, Detroit, MI 48202, USA; (J.K.); (E.D.-B.); (L.M.F.); (L.Z.); (G.D.); (Z.Z.); (M.C.)
- Department of Physics, Oakland University, Rochester, MI 48309, USA
- Correspondence: ; Tel.: +1-313-916-8735; Fax: +1-313-916-1324
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48
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Vinje V, Eklund A, Mardal KA, Rognes ME, Støverud KH. Intracranial pressure elevation alters CSF clearance pathways. Fluids Barriers CNS 2020; 17:29. [PMID: 32299464 PMCID: PMC7161287 DOI: 10.1186/s12987-020-00189-1] [Citation(s) in RCA: 43] [Impact Index Per Article: 10.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/05/2019] [Accepted: 03/28/2020] [Indexed: 12/15/2022] Open
Abstract
BACKGROUND Infusion testing is a common procedure to determine whether shunting will be beneficial in patients with normal pressure hydrocephalus. The method has a well-developed theoretical foundation and corresponding mathematical models that describe the CSF circulation from the choroid plexus to the arachnoid granulations. Here, we investigate to what extent the proposed glymphatic or paravascular pathway (or similar pathways) modifies the results of the traditional mathematical models. METHODS We used a compartment model to estimate pressure in the subarachnoid space and the paravascular spaces. For the arachnoid granulations, the cribriform plate and the glymphatic circulation, resistances were calculated and used to estimate pressure and flow before and during an infusion test. Finally, different variations to the model were tested to evaluate the sensitivity of selected parameters. RESULTS At baseline intracranial pressure (ICP), we found a very small paravascular flow directed into the subarachnoid space, while 60% of the fluid left through the arachnoid granulations and 40% left through the cribriform plate. However, during the infusion, 80% of the fluid left through the arachnoid granulations, 20% through the cribriform plate and flow in the PVS was stagnant. Resistance through the glymphatic system was computed to be 2.73 mmHg/(mL/min), considerably lower than other fluid pathways, giving non-realistic ICP during infusion if combined with a lymphatic drainage route. CONCLUSIONS The relative distribution of CSF flow to different clearance pathways depends on ICP, with the arachnoid granulations as the main contributor to outflow. As such, ICP increase is an important factor that should be addressed when determining the pathways of injected substances in the subarachnoid space. Our results suggest that the glymphatic resistance is too high to allow for pressure driven flow by arterial pulsations and at the same time too small to allow for a direct drainage route from PVS to cervical lymphatics.
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Affiliation(s)
- Vegard Vinje
- Department of Scientific Computing and Numerical Analysis, Simula Research Laboratory, Lysaker, Norway.
| | - Anders Eklund
- Department of Radiation Sciences, Umeå University, Umeå, Sweden
| | - Kent-Andre Mardal
- Department of Scientific Computing and Numerical Analysis, Simula Research Laboratory, Lysaker, Norway.,Department of Mathematics, University of Oslo, Oslo, Norway
| | - Marie E Rognes
- Department of Scientific Computing and Numerical Analysis, Simula Research Laboratory, Lysaker, Norway
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Perivascular spaces in the brain: anatomy, physiology and pathology. Nat Rev Neurol 2020; 16:137-153. [PMID: 32094487 DOI: 10.1038/s41582-020-0312-z] [Citation(s) in RCA: 391] [Impact Index Per Article: 97.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 01/14/2020] [Indexed: 02/06/2023]
Abstract
Perivascular spaces include a variety of passageways around arterioles, capillaries and venules in the brain, along which a range of substances can move. Although perivascular spaces were first identified over 150 years ago, they have come to prominence recently owing to advances in knowledge of their roles in clearance of interstitial fluid and waste from the brain, particularly during sleep, and in the pathogenesis of small vessel disease, Alzheimer disease and other neurodegenerative and inflammatory disorders. Experimental advances have facilitated in vivo studies of perivascular space function in intact rodent models during wakefulness and sleep, and MRI in humans has enabled perivascular space morphology to be related to cognitive function, vascular risk factors, vascular and neurodegenerative brain lesions, sleep patterns and cerebral haemodynamics. Many questions about perivascular spaces remain, but what is now clear is that normal perivascular space function is important for maintaining brain health. Here, we review perivascular space anatomy, physiology and pathology, particularly as seen with MRI in humans, and consider translation from models to humans to highlight knowns, unknowns, controversies and clinical relevance.
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Beldman T, Malinova TS, Desclos E, Grootemaat AE, Misiak ALS, van der Velden S, van Roomen CPAA, Beckers L, van Veen HA, Krawczyk PM, Hoebe RA, Sluimer JC, Neele AE, de Winther MPJ, van der Wel NN, Lutgens E, Mulder WJM, Huveneers S, Kluza E. Nanoparticle-Aided Characterization of Arterial Endothelial Architecture during Atherosclerosis Progression and Metabolic Therapy. ACS NANO 2019; 13:13759-13774. [PMID: 31268670 PMCID: PMC6933811 DOI: 10.1021/acsnano.8b08875] [Citation(s) in RCA: 58] [Impact Index Per Article: 11.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/21/2018] [Accepted: 07/03/2019] [Indexed: 05/08/2023]
Abstract
Atherosclerosis is associated with a compromised endothelial barrier, facilitating the accumulation of immune cells and macromolecules in atherosclerotic lesions. In this study, we investigate endothelial barrier integrity and the enhanced permeability and retention (EPR) effect during atherosclerosis progression and therapy in Apoe-/- mice using hyaluronan nanoparticles (HA-NPs). Utilizing ultrastructural and en face plaque imaging, we uncover a significantly decreased junction continuity in the atherosclerotic plaque-covering endothelium compared to the normal vessel wall, indicative of disrupted endothelial barrier. Intriguingly, the plaque advancement had a positive effect on junction stabilization, which correlated with a 3-fold lower accumulation of in vivo administrated HA-NPs in advanced plaques compared to early counterparts. Furthermore, by using super-resolution and correlative light and electron microscopy, we trace nanoparticles in the plaque microenvironment. We find nanoparticle-enriched endothelial junctions, containing 75% of detected HA-NPs, and a high HA-NP accumulation in the endothelium-underlying extracellular matrix, which suggest an endothelial junctional traffic of HA-NPs to the plague. Finally, we probe the EPR effect by HA-NPs in the context of metabolic therapy with a glycolysis inhibitor, 3PO, proposed as a vascular normalizing strategy. The observed trend of attenuated HA-NP uptake in aortas of 3PO-treated mice coincides with the endothelial silencing activity of 3PO, demonstrated in vitro. Interestingly, the therapy also reduced the plaque inflammatory burden, while activating macrophage metabolism. Our findings shed light on natural limitations of nanoparticle accumulation in atherosclerotic plaques and provide mechanistic insight into nanoparticle trafficking across the atherosclerotic endothelium. Furthermore, our data contribute to the rising field of endothelial barrier modulation in atherosclerosis.
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Affiliation(s)
- Thijs
J. Beldman
- Experimental
Vascular Biology, Department of Medical Biochemistry, Amsterdam Cardiovascular
Sciences (ACS), Amsterdam University Medical
Center, Amsterdam 1105 AZ, The Netherlands
| | - Tsveta S. Malinova
- Vascular
Microenvironment and Integrity, Department of Medical Biochemistry,
Amsterdam Cardiovascular Sciences (ACS), Amsterdam University Medical Center, Amsterdam 1105 AZ, The
Netherlands
| | - Emilie Desclos
- Cellular
Imaging-Core Facility, Academic Medical
Center, Amsterdam 1105 AZ, The Netherlands
| | - Anita E. Grootemaat
- Cellular
Imaging-Core Facility, Academic Medical
Center, Amsterdam 1105 AZ, The Netherlands
| | - Aresh L. S. Misiak
- Experimental
Vascular Biology, Department of Medical Biochemistry, Amsterdam Cardiovascular
Sciences (ACS), Amsterdam University Medical
Center, Amsterdam 1105 AZ, The Netherlands
| | - Saskia van der Velden
- Experimental
Vascular Biology, Department of Medical Biochemistry, Amsterdam Cardiovascular
Sciences (ACS), Amsterdam University Medical
Center, Amsterdam 1105 AZ, The Netherlands
| | - Cindy P. A. A. van Roomen
- Experimental
Vascular Biology, Department of Medical Biochemistry, Amsterdam Cardiovascular
Sciences (ACS), Amsterdam University Medical
Center, Amsterdam 1105 AZ, The Netherlands
| | - Linda Beckers
- Experimental
Vascular Biology, Department of Medical Biochemistry, Amsterdam Cardiovascular
Sciences (ACS), Amsterdam University Medical
Center, Amsterdam 1105 AZ, The Netherlands
| | - Henk A. van Veen
- Cellular
Imaging-Core Facility, Academic Medical
Center, Amsterdam 1105 AZ, The Netherlands
| | - Przemyslaw M. Krawczyk
- Department
of Medical Biology, Amsterdam University
Medical Center, Amsterdam 1105 AZ, The Netherlands
| | - Ron A. Hoebe
- Cellular
Imaging-Core Facility, Academic Medical
Center, Amsterdam 1105 AZ, The Netherlands
| | - Judith C. Sluimer
- Department
of Pathology, Cardiovascular Research Institute Maastricht (CARIM), Maastricht University Medical Center, Maastricht 6229 ER, The Netherlands
| | - Annette E. Neele
- Experimental
Vascular Biology, Department of Medical Biochemistry, Amsterdam Cardiovascular
Sciences (ACS), Amsterdam University Medical
Center, Amsterdam 1105 AZ, The Netherlands
| | - Menno P. J. de Winther
- Experimental
Vascular Biology, Department of Medical Biochemistry, Amsterdam Cardiovascular
Sciences (ACS), Amsterdam University Medical
Center, Amsterdam 1105 AZ, The Netherlands
- Institute
for Cardiovascular Prevention, Ludwig Maximilians
University, Munich 80336, Germany
| | - Nicole N. van der Wel
- Cellular
Imaging-Core Facility, Academic Medical
Center, Amsterdam 1105 AZ, The Netherlands
| | - Esther Lutgens
- Experimental
Vascular Biology, Department of Medical Biochemistry, Amsterdam Cardiovascular
Sciences (ACS), Amsterdam University Medical
Center, Amsterdam 1105 AZ, The Netherlands
- Institute
for Cardiovascular Prevention, Ludwig Maximilians
University, Munich 80336, Germany
| | - Willem J. M. Mulder
- Experimental
Vascular Biology, Department of Medical Biochemistry, Amsterdam Cardiovascular
Sciences (ACS), Amsterdam University Medical
Center, Amsterdam 1105 AZ, The Netherlands
- Translational
and Molecular Imaging Institute, Icahn School
of Medicine at Mount Sinai, New York, New York 10029, United States
| | - Stephan Huveneers
- Vascular
Microenvironment and Integrity, Department of Medical Biochemistry,
Amsterdam Cardiovascular Sciences (ACS), Amsterdam University Medical Center, Amsterdam 1105 AZ, The
Netherlands
| | - Ewelina Kluza
- Experimental
Vascular Biology, Department of Medical Biochemistry, Amsterdam Cardiovascular
Sciences (ACS), Amsterdam University Medical
Center, Amsterdam 1105 AZ, The Netherlands
| |
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