401
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Abstract
During sleep, the brain experiences large fluctuations in blood volume and altered coupling between neural and vascular signals.
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Affiliation(s)
- Stephanie D Williams
- Department of Psychological and Brain Sciences, Boston University, Boston, United States
| | - Laura D Lewis
- Department of Biomedical Engineering, Boston University, Boston, United States
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402
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Hariharan A, Weir N, Robertson C, He L, Betsholtz C, Longden TA. The Ion Channel and GPCR Toolkit of Brain Capillary Pericytes. Front Cell Neurosci 2020; 14:601324. [PMID: 33390906 PMCID: PMC7775489 DOI: 10.3389/fncel.2020.601324] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 11/13/2020] [Indexed: 12/14/2022] Open
Abstract
Brain pericytes reside on the abluminal surface of capillaries, and their processes cover ~90% of the length of the capillary bed. These cells were first described almost 150 years ago (Eberth, 1871; Rouget, 1873) and have been the subject of intense experimental scrutiny in recent years, but their physiological roles remain uncertain and little is known of the complement of signaling elements that they employ to carry out their functions. In this review, we synthesize functional data with single-cell RNAseq screens to explore the ion channel and G protein-coupled receptor (GPCR) toolkit of mesh and thin-strand pericytes of the brain, with the aim of providing a framework for deeper explorations of the molecular mechanisms that govern pericyte physiology. We argue that their complement of channels and receptors ideally positions capillary pericytes to play a central role in adapting blood flow to meet the challenge of satisfying neuronal energy requirements from deep within the capillary bed, by enabling dynamic regulation of their membrane potential to influence the electrical output of the cell. In particular, we outline how genetic and functional evidence suggest an important role for Gs-coupled GPCRs and ATP-sensitive potassium (KATP) channels in this context. We put forth a predictive model for long-range hyperpolarizing electrical signaling from pericytes to upstream arterioles, and detail the TRP and Ca2+ channels and Gq, Gi/o, and G12/13 signaling processes that counterbalance this. We underscore critical questions that need to be addressed to further advance our understanding of the signaling topology of capillary pericytes, and how this contributes to their physiological roles and their dysfunction in disease.
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Affiliation(s)
- Ashwini Hariharan
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Nick Weir
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Colin Robertson
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
| | - Liqun He
- Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden
| | - Christer Betsholtz
- Rudbeck Laboratory, Department of Immunology, Genetics and Pathology, Uppsala University, Uppsala, Sweden.,Department of Medicine Huddinge (MedH), Karolinska Institutet & Integrated Cardio Metabolic Centre, Huddinge, Sweden
| | - Thomas A Longden
- Department of Physiology, School of Medicine, University of Maryland, Baltimore, MD, United States
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403
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Choi Y, Nam Y, Choi Y, Kim J, Jang J, Ahn KJ, Kim BS, Shin NY. MRI-visible dilated perivascular spaces in healthy young adults: A twin heritability study. Hum Brain Mapp 2020; 41:5313-5324. [PMID: 32897599 PMCID: PMC7670636 DOI: 10.1002/hbm.25194] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/24/2019] [Revised: 08/05/2020] [Accepted: 08/12/2020] [Indexed: 12/24/2022] Open
Abstract
We investigated the narrow‐sense heritability of MRI‐visible dilated perivascular spaces (dPVS) in healthy young adult twins and nontwin siblings (138 monozygotic, 79 dizygotic twin pairs, and 133 nontwin sibling pairs; 28.7 ± 3.6 years) from the Human Connectome Project. dPVS volumes within basal ganglia (BGdPVS) and white matter (WMdPVS) were automatically calculated on three‐dimensional T2‐weighted MRI. In univariate analysis, heritability estimates of BGdPVS and WMdPVS after age and sex adjustment were 65.8% and 90.2%. In bivariate analysis, both BGdPVS and WMdPVS showed low to moderate genetic correlations (.30–.43) but high shared heritabilities (71.8–99.9%) with corresponding regional volumes, intracranial volumes, and other regional dPVS volumes. Older age was significantly associated with larger dPVS volume in both regions even after adjusting for clinical and volumetric variables, while blood pressure was not associated with dPVS volume although there was weak genetic correlation. dPVS volume, particularly WMdPVS, was highly heritable in healthy young adults, adding evidence of a substantial genetic contribution in dPVS development and differential effect by location. Age affects dPVS volume even in young adults, while blood pressure might have limited role in dPVS development in its normal range.
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Affiliation(s)
- Yangsean Choi
- Department of Radiology, Seoul Saint Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Yoonho Nam
- Division of Biomedical Engineering, Hankuk University of Foreign Studies, Yongin-Si, Republic of Korea
| | - Yera Choi
- Department of Radiology, Seoul Saint Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Jiwoong Kim
- Department of Radiology, Seoul Saint Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Jinhee Jang
- Department of Radiology, Seoul Saint Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Kook Jin Ahn
- Department of Radiology, Seoul Saint Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Bum-Soo Kim
- Department of Radiology, Seoul Saint Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
| | - Na-Young Shin
- Department of Radiology, Seoul Saint Mary's Hospital, College of Medicine, The Catholic University of Korea, Seoul, Republic of Korea
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404
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Dur AH, Tang T, Viviano S, Sekuri A, Willsey HR, Tagare HD, Kahle KT, Deniz E. In Xenopus ependymal cilia drive embryonic CSF circulation and brain development independently of cardiac pulsatile forces. Fluids Barriers CNS 2020; 17:72. [PMID: 33308296 PMCID: PMC7731788 DOI: 10.1186/s12987-020-00234-z] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2020] [Accepted: 11/28/2020] [Indexed: 12/14/2022] Open
Abstract
BACKGROUND Hydrocephalus, the pathological expansion of the cerebrospinal fluid (CSF)-filled cerebral ventricles, is a common, deadly disease. In the adult, cardiac and respiratory forces are the main drivers of CSF flow within the brain ventricular system to remove waste and deliver nutrients. In contrast, the mechanics and functions of CSF circulation in the embryonic brain are poorly understood. This is primarily due to the lack of model systems and imaging technology to study these early time points. Here, we studied embryos of the vertebrate Xenopus with optical coherence tomography (OCT) imaging to investigate in vivo ventricular and neural development during the onset of CSF circulation. METHODS Optical coherence tomography (OCT), a cross-sectional imaging modality, was used to study developing Xenopus tadpole brains and to dynamically detect in vivo ventricular morphology and CSF circulation in real-time, at micrometer resolution. The effects of immobilizing cilia and cardiac ablation were investigated. RESULTS In Xenopus, using OCT imaging, we demonstrated that ventriculogenesis can be tracked throughout development until the beginning of metamorphosis. We found that during Xenopus embryogenesis, initially, CSF fills the primitive ventricular space and remains static, followed by the initiation of the cilia driven CSF circulation where ependymal cilia create a polarized CSF flow. No pulsatile flow was detected throughout these tailbud and early tadpole stages. As development progressed, despite the emergence of the choroid plexus in Xenopus, cardiac forces did not contribute to the CSF circulation, and ciliary flow remained the driver of the intercompartmental bidirectional flow as well as the near-wall flow. We finally showed that cilia driven flow is crucial for proper rostral development and regulated the spatial neural cell organization. CONCLUSIONS Our data support a paradigm in which Xenopus embryonic ventriculogenesis and rostral brain development are critically dependent on ependymal cilia-driven CSF flow currents that are generated independently of cardiac pulsatile forces. Our work suggests that the Xenopus ventricular system forms a complex cilia-driven CSF flow network which regulates neural cell organization. This work will redirect efforts to understand the molecular regulators of embryonic CSF flow by focusing attention on motile cilia rather than other forces relevant only to the adult.
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Affiliation(s)
- A H Dur
- Department of Pediatrics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06510, USA
- Acibadem Mehmet Ali Aydinlar University School of Medicine, Istanbul, Turkey
| | - T Tang
- Department of Radiology and Biomedical Imaging, Yale University, 300 Cedar St, New Haven, CT, 06510, USA
| | - S Viviano
- Department of Pediatrics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06510, USA
- Pediatric Genomics Discovery Program, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06510, USA
| | - A Sekuri
- Acibadem Mehmet Ali Aydinlar University School of Medicine, Istanbul, Turkey
| | - H R Willsey
- Department of Psychiatry and Behavioral Sciences, UCSF Weill Institute for Neurosciences, University of California, San Francisco, San Francisco, CA, 94143, USA
| | - H D Tagare
- Department of Radiology and Biomedical Imaging, Yale University, 300 Cedar St, New Haven, CT, 06510, USA
| | - K T Kahle
- Department of Pediatrics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06510, USA
- Department of Neurosurgery and Cellular & Molecular Physiology, and Centers for Mendelian Genomics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06510, USA
| | - E Deniz
- Department of Pediatrics, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06510, USA.
- Pediatric Genomics Discovery Program, Yale University School of Medicine, 333 Cedar Street, New Haven, CT, 06510, USA.
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405
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Tuovinen T, Kananen J, Rajna Z, Lieslehto J, Korhonen V, Rytty R, Mattila H, Huotari N, Raitamaa L, Helakari H, Elseoud AA, Krüger J, LeVan P, Tervonen O, Hennig J, Remes AM, Nedergaard M, Kiviniemi V. The variability of functional MRI brain signal increases in Alzheimer's disease at cardiorespiratory frequencies. Sci Rep 2020; 10:21559. [PMID: 33298996 PMCID: PMC7726142 DOI: 10.1038/s41598-020-77984-1] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2020] [Accepted: 11/13/2020] [Indexed: 01/08/2023] Open
Abstract
Biomarkers sensitive to prodromal or early pathophysiological changes in Alzheimer's disease (AD) symptoms could improve disease detection and enable timely interventions. Changes in brain hemodynamics may be associated with the main clinical AD symptoms. To test this possibility, we measured the variability of blood oxygen level-dependent (BOLD) signal in individuals from three independent datasets (totaling 80 AD patients and 90 controls). We detected a replicable increase in brain BOLD signal variability in the AD populations, which constituted a robust biomarker for clearly differentiating AD cases from controls. Fast BOLD scans showed that the elevated BOLD signal variability in AD arises mainly from cardiovascular brain pulsations. Manifesting in abnormal cerebral perfusion and cerebrospinal fluid convection, present observation presents a mechanism explaining earlier observations of impaired glymphatic clearance associated with AD in humans.
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Affiliation(s)
- Timo Tuovinen
- Oulu Functional Neuroimaging, Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland.
- Medical Research Center, Oulu University Hospital, Oulu, Finland.
| | - Janne Kananen
- Oulu Functional Neuroimaging, Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland
- Medical Research Center, Oulu University Hospital, Oulu, Finland
| | - Zalan Rajna
- Oulu Functional Neuroimaging, Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland
- Center for Machine Vision and Signal Analysis, University of Oulu, Oulu, Finland
| | - Johannes Lieslehto
- Center for Life Course Health Research, University of Oulu, Oulu, Finland
| | - Vesa Korhonen
- Oulu Functional Neuroimaging, Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland
- Medical Research Center, Oulu University Hospital, Oulu, Finland
| | - Riikka Rytty
- Oulu Functional Neuroimaging, Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland
- Department of Neurology, Hyvinkää Hospital, Helsinki University Hospital, Hyvinkää, Finland
| | - Heli Mattila
- Oulu Functional Neuroimaging, Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland
- Medical Research Center, Oulu University Hospital, Oulu, Finland
| | - Niko Huotari
- Oulu Functional Neuroimaging, Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland
- Medical Research Center, Oulu University Hospital, Oulu, Finland
| | - Lauri Raitamaa
- Oulu Functional Neuroimaging, Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland
- Medical Research Center, Oulu University Hospital, Oulu, Finland
| | - Heta Helakari
- Oulu Functional Neuroimaging, Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland
- Medical Research Center, Oulu University Hospital, Oulu, Finland
| | - Ahmed Abou Elseoud
- Department of Diagnostic Radiology, Helsinki University Hospital, Helsinki, Finland
| | - Johanna Krüger
- Medical Research Center, Oulu University Hospital, Oulu, Finland
- Research Unit of Clinical Neuroscience, Neurology, University of Oulu, Oulu, Finland
| | - Pierre LeVan
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
- Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, Canada
- Department of Paediatrics, Cumming School of Medicine, University of Calgary, Calgary, Canada
- Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, University of Calgary, Calgary, Canada
| | - Osmo Tervonen
- Oulu Functional Neuroimaging, Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland
- Medical Research Center, Oulu University Hospital, Oulu, Finland
| | - Juergen Hennig
- Department of Radiology, Medical Physics, Medical Center - University of Freiburg, Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Anne M Remes
- Medical Research Center, Oulu University Hospital, Oulu, Finland
- Research Unit of Clinical Neuroscience, Neurology, University of Oulu, Oulu, Finland
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, USA
| | - Vesa Kiviniemi
- Oulu Functional Neuroimaging, Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland.
- Medical Research Center, Oulu University Hospital, Oulu, Finland.
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406
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Romanò F, Suresh V, Galie PA, Grotberg JB. Peristaltic flow in the glymphatic system. Sci Rep 2020; 10:21065. [PMID: 33273489 PMCID: PMC7713425 DOI: 10.1038/s41598-020-77787-4] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/10/2020] [Accepted: 11/12/2020] [Indexed: 01/01/2023] Open
Abstract
The flow inside the perivascular space (PVS) is modeled using a first-principles approach in order to investigate how the cerebrospinal fluid (CSF) enters the brain through a permeable layer of glial cells. Lubrication theory is employed to deal with the flow in the thin annular gap of the perivascular space between an impermeable artery and the brain tissue. The artery has an imposed peristaltic deformation and the deformable brain tissue is modeled by means of an elastic Hooke's law. The perivascular flow model is solved numerically, discovering that the peristaltic wave induces a steady streaming to/from the brain which strongly depends on the rigidity and the permeability of the brain tissue. A detailed quantification of the through flow across the glial boundary is obtained for a large parameter space of physiologically relevant conditions. The parameters include the elasticity and permeability of the brain, the curvature of the artery, its length and the amplitude of the peristaltic wave. A steady streaming component of the through flow due to the peristaltic wave is characterized by an in-depth physical analysis and the velocity across the glial layer is found to flow from and to the PVS, depending on the elasticity and permeability of the brain. The through CSF flow velocity is quantified to be of the order of micrometers per seconds.
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Affiliation(s)
- Francesco Romanò
- Univ. Lille, CNRS, ONERA, Arts et Métiers Institute of Technology, Centrale Lille, UMR 9014 - LMFL - Laboratoire de Mécanique des Fluides de Lille - Kampé de Fériet, 59000, Lille, France.
| | - Vinod Suresh
- Auckland Bioeng. Inst. and Dept. Eng. Sci., University of Auckland, 70 Symonds Street, Bldg 439, Auckland, 1010, New Zealand
| | - Peter A Galie
- Dept. Biomed. Eng., Rowan University, 201 Mullica Hill Rd, Glassboro, NJ, 08028, USA
| | - James B Grotberg
- Dept. Biomed. Eng., University of Michigan, 2123 Carl A. Gerstacker Building, 2200 Bonisteel Boulevard, Ann Arbor, MI, 48109-2099, USA
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407
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Kainulainen S, Duce B, Korkalainen H, Leino A, Huttunen R, Kalevo L, Arnardottir ES, Kulkas A, Myllymaa S, Töyräs J, Leppänen T. Increased nocturnal arterial pulsation frequencies of obstructive sleep apnoea patients is associated with an increased number of lapses in a psychomotor vigilance task. ERJ Open Res 2020; 6:00277-2020. [PMID: 33263035 PMCID: PMC7682668 DOI: 10.1183/23120541.00277-2020] [Citation(s) in RCA: 4] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/15/2020] [Accepted: 08/28/2020] [Indexed: 12/28/2022] Open
Abstract
Objectives Besides hypoxaemia severity, heart rate variability has been linked to cognitive decline in obstructive sleep apnoea (OSA) patients. Thus, our aim was to examine whether the frequency domain features of a nocturnal photoplethysmogram (PPG) can be linked to poor performance in the psychomotor vigilance task (PVT). Methods PPG signals from 567 suspected OSA patients, extracted from Type 1 diagnostic polysomnography, and corresponding results of PVT were retrospectively examined. The frequency content of complete PPGs was determined, and analyses were conducted separately for men (n=327) and women (n=240). Patients were grouped into PVT performance quartiles based on the number of lapses (reaction times ≥500 ms) and within-test variation in reaction times. The best-performing (Q1) and worst-performing (Q4) quartiles were compared due the lack of clinical thresholds in PVT. Results We found that the increase in arterial pulsation frequency (APF) in both men and women was associated with a higher number of lapses. Higher APF was also associated with higher within-test variation in men, but not in women. Median APF (β=0.27, p=0.01), time spent under 90% saturation (β=0.05, p<0.01), female sex (β=1.29, p<0.01), older age (β=0.03, p<0.01) and subjective sleepiness (β=0.07, p<0.01) were significant predictors of belonging to Q4 based on lapses. Only female sex (β=0.75, p<0.01) and depression (β=0.91, p<0.02) were significant predictors of belonging to Q4 based on the within-test variation. Conclusions In conclusion, increased APF in PPG provides a possible polysomnography indicator for deteriorated vigilance especially in male OSA patients. This finding highlights the connection between cardiorespiratory regulation, vigilance and OSA. However, our results indicate substantial sex-dependent differences that warrant further prospective studies.
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Affiliation(s)
- Samu Kainulainen
- Dept of Applied Physics, University of Eastern Finland, Kuopio, Finland.,Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland
| | - Brett Duce
- Sleep Disorders Centre, Dept of Respiratory and Sleep Medicine, Princess Alexandra Hospital, Brisbane, Australia.,Institute for Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia
| | - Henri Korkalainen
- Dept of Applied Physics, University of Eastern Finland, Kuopio, Finland.,Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland
| | - Akseli Leino
- Dept of Applied Physics, University of Eastern Finland, Kuopio, Finland.,Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland
| | - Riku Huttunen
- Dept of Applied Physics, University of Eastern Finland, Kuopio, Finland
| | - Laura Kalevo
- Dept of Applied Physics, University of Eastern Finland, Kuopio, Finland.,Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland
| | - Erna S Arnardottir
- Dept of Computer Science, Reykjavik University, Reykjavik, Iceland.,Internal Medicine Services, Landspitali - The National University Hospital of Iceland, Reykjavik, Iceland
| | - Antti Kulkas
- Dept of Applied Physics, University of Eastern Finland, Kuopio, Finland.,Dept of Clinical Neurophysiology, Seinäjoki Central Hospital, Seinäjoki, Finland
| | - Sami Myllymaa
- Dept of Applied Physics, University of Eastern Finland, Kuopio, Finland.,Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland
| | - Juha Töyräs
- Dept of Applied Physics, University of Eastern Finland, Kuopio, Finland.,Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland.,School of Information Technology and Electrical Engineering, The University of Queensland, Brisbane, Australia
| | - Timo Leppänen
- Dept of Applied Physics, University of Eastern Finland, Kuopio, Finland.,Diagnostic Imaging Center, Kuopio University Hospital, Kuopio, Finland
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408
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Abstract
The glymphatic system is network of perivascular spaces through which cerebrospinal fluid and interstitial fluid can move through the brain, clearing metabolic waste, such as amyloid beta, lactate and more, from the parenchyma. This cleaning system is regulated by sleep and norepinephrine, with increased levels of norepinephrine during wakefulness inhibiting fluid movement. Norepinephrine is also essential for transition from acute to chronic pain, and sufferers of chronic neuropathic pain frequently present with sleep disruption. These connections among glymphatic clearance, sleep, and pain are very intriguing, and might lead to nonpharmaceutical interventions for pain treatment. This short perspective provides a rationale for the hypothesis that mind-body interventions-such as acupuncture-can reduce norepinephrine and increase glymphatic function, ultimately relieving chronic neuropathic pain.
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Affiliation(s)
- Nanna Goldman
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, USA
| | - Lauren M Hablitz
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, USA
| | - Yuki Mori
- Center for Basic and Translational Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, USA.,Center for Basic and Translational Neuroscience, University of Copenhagen, Copenhagen, Denmark
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409
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Vikner T, Nyberg L, Holmgren M, Malm J, Eklund A, Wåhlin A. Characterizing pulsatility in distal cerebral arteries using 4D flow MRI. J Cereb Blood Flow Metab 2020; 40:2429-2440. [PMID: 31722598 PMCID: PMC7820688 DOI: 10.1177/0271678x19886667] [Citation(s) in RCA: 17] [Impact Index Per Article: 4.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Recent reports have suggested that age-related arterial stiffening and excessive cerebral arterial pulsatility cause blood-brain barrier breakdown, brain atrophy and cognitive decline. This has spurred interest in developing non-invasive methods to measure pulsatility in distal vessels, closer to the cerebral microcirculation. Here, we report a method based on four-dimensional (4D) flow MRI to estimate a global composite flow waveform of distal cerebral arteries. The method is based on finding and sampling arterial waveforms from thousands of cross sections in numerous small vessels of the brain, originating from cerebral cortical arteries. We demonstrate agreement with internal and external reference methods and show the ability to capture significant increases in distal cerebral arterial pulsatility as a function of age. The proposed approach can be used to advance our understanding regarding excessive arterial pulsatility as a potential trigger of cognitive decline and dementia.
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Affiliation(s)
- Tomas Vikner
- Department of Radiation Sciences, Umeå University, Umeå, Sweden
- Tomas Vikner, Department of Radiation Sciences, Umeå University, Umeå SE 901 87, Sweden.
| | - Lars Nyberg
- Department of Radiation Sciences, Umeå University, Umeå, Sweden
- Umeå Center for Functional Brain Imaging (UFBI), Umeå University, Umeå, Sweden
- Department of Integrative Medical Biology (IMB), Umeå University, Umeå, Sweden
| | | | - Jan Malm
- Department of Pharmacology and Clinical Neuroscience, Umeå University, Umeå, Sweden
| | - Anders Eklund
- Department of Radiation Sciences, Umeå University, Umeå, Sweden
- Umeå Center for Functional Brain Imaging (UFBI), Umeå University, Umeå, Sweden
| | - Anders Wåhlin
- Department of Radiation Sciences, Umeå University, Umeå, Sweden
- Umeå Center for Functional Brain Imaging (UFBI), Umeå University, Umeå, Sweden
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410
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Benveniste H, Lee H, Ozturk B, Chen X, Koundal S, Vaska P, Tannenbaum A, Volkow ND. Glymphatic Cerebrospinal Fluid and Solute Transport Quantified by MRI and PET Imaging. Neuroscience 2020; 474:63-79. [PMID: 33248153 DOI: 10.1016/j.neuroscience.2020.11.014] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2020] [Revised: 11/04/2020] [Accepted: 11/07/2020] [Indexed: 12/13/2022]
Abstract
Over the past decade there has been an enormous progress in our understanding of fluid and solute transport in the central nervous system (CNS). This is due to a number of factors, including important developments in whole brain imaging technology and computational fluid dynamics analysis employed for the elucidation of glymphatic transport function in the live animal and human brain. In this paper, we review the technical aspects of dynamic contrast enhanced magnetic resonance imaging (DCE-MRI) in combination with administration of Gd-based tracers into the cerebrospinal fluid (CSF) for tracking glymphatic solute and fluid transport in the CNS as well as lymphatic drainage. Used in conjunction with advanced computational processing methods including optimal mass transport analysis, one gains new insights into the biophysical forces governing solute transport in the CNS which leads to intriguing new research directions. Considering drainage pathways, we review the novel T1 mapping technique for quantifying glymphatic transport and cervical lymph node drainage concurrently in the same subject. We provide an overview of knowledge gleaned from DCE-MRI studies of glymphatic transport and meningeal lymphatic drainage. Finally, we introduce positron emission tomography (PET) and CSF administration of radiotracers as an alternative method to explore other pharmacokinetic aspects of CSF transport into brain parenchyma as well as efflux pathways.
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Affiliation(s)
- Helene Benveniste
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT, United States; Department of Biomedical Engineering, Yale School of Medicine, New Haven, CT, United States.
| | - Hedok Lee
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT, United States
| | - Burhan Ozturk
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT, United States
| | - Xinan Chen
- Departments of Computer Science and Applied Mathematics & Statistics, Stony Brook University, Stony Brook, NY, United States
| | - Sunil Koundal
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT, United States
| | - Paul Vaska
- Department of Radiology and Biomedical Engineering, Renaissance School of Medicine at Stony Brook University, Stony Brook, NY, United States
| | - Allen Tannenbaum
- Departments of Computer Science and Applied Mathematics & Statistics, Stony Brook University, Stony Brook, NY, United States
| | - Nora D Volkow
- Laboratory for Neuroimaging, NIAAA, Bethesda, MD, United States
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411
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Howe MD, McCullough LD, Urayama A. The Role of Basement Membranes in Cerebral Amyloid Angiopathy. Front Physiol 2020; 11:601320. [PMID: 33329053 PMCID: PMC7732667 DOI: 10.3389/fphys.2020.601320] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2020] [Accepted: 10/28/2020] [Indexed: 12/25/2022] Open
Abstract
Dementia is a neuropsychiatric syndrome characterized by cognitive decline in multiple domains, often leading to functional impairment in activities of daily living, disability, and death. The most common causes of age-related progressive dementia include Alzheimer's disease (AD) and vascular cognitive impairment (VCI), however, mixed disease pathologies commonly occur, as epitomized by a type of small vessel pathology called cerebral amyloid angiopathy (CAA). In CAA patients, the small vessels of the brain become hardened and vulnerable to rupture, leading to impaired neurovascular coupling, multiple microhemorrhage, microinfarction, neurological emergencies, and cognitive decline across multiple functional domains. While the pathogenesis of CAA is not well understood, it has long been thought to be initiated in thickened basement membrane (BM) segments, which contain abnormal protein deposits and amyloid-β (Aβ). Recent advances in our understanding of CAA pathogenesis link BM remodeling to functional impairment of perivascular transport pathways that are key to removing Aβ from the brain. Dysregulation of this process may drive CAA pathogenesis and provides an important link between vascular risk factors and disease phenotype. The present review summarizes how the structure and composition of the BM allows for perivascular transport pathways to operate in the healthy brain, and then outlines multiple mechanisms by which specific dementia risk factors may promote dysfunction of perivascular transport pathways and increase Aβ deposition during CAA pathogenesis. A better understanding of how BM remodeling alters perivascular transport could lead to novel diagnostic and therapeutic strategies for CAA patients.
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Affiliation(s)
| | | | - Akihiko Urayama
- Department of Neurology, McGovern Medical School, The University of Texas Health Science Center at Houston, Houston, TX, United States
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412
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Young BA, Adams J, Beary JM, Mardal KA, Schneider R, Kondrashova T. The myodural bridge of the American alligator ( Alligator mississippiensis) alters CSF flow. J Exp Biol 2020; 223:jeb230896. [PMID: 33077640 DOI: 10.1242/jeb.230896] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Accepted: 10/11/2020] [Indexed: 12/19/2022]
Abstract
Disorders of the volume, pressure or circulation of the cerebrospinal fluid (CSF) lead to disease states in both newborns and adults; despite this significance, there is uncertainty regarding the basic mechanics of the CSF. The suboccipital muscles connect to the dura surrounding the spinal cord, forming a complex termed the 'myodural bridge'. This study tests the hypothesis that the myodural bridge functions to alter the CSF circulation. The suboccipital muscles of American alligators were surgically exposed and electrically stimulated simultaneously with direct recordings of CSF pressure and flow. Contraction of the suboccipital muscles significantly changed both CSF flow and pressure. By demonstrating another influence on CSF circulation and pulsatility, the present study increases our understanding of the mechanics underlying the movement of the CSF.
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Affiliation(s)
- Bruce A Young
- Department of Anatomy, Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, MO 63501, USA
| | - James Adams
- Department of Anatomy, Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, MO 63501, USA
| | - Jonathan M Beary
- Department of Behavioral Neuroscience, Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, MO 63501, USA
| | | | - Robert Schneider
- Department of Family Medicine, Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, MO 63501, USA
| | - Tatyana Kondrashova
- Department of Family Medicine, Kirksville College of Osteopathic Medicine, A.T. Still University, Kirksville, MO 63501, USA
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413
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Min Rivas F, Liu J, Martell BC, Du T, Mestre H, Nedergaard M, Tithof J, Thomas JH, Kelley DH. Surface periarterial spaces of the mouse brain are open, not porous. J R Soc Interface 2020; 17:20200593. [PMID: 33171075 DOI: 10.1098/rsif.2020.0593] [Citation(s) in RCA: 23] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/15/2022] Open
Abstract
Fluid-dynamic models of the flow of cerebrospinal fluid in the brain have treated the perivascular spaces either as open (without internal solid obstacles) or as porous. Here, we present experimental evidence that pial (surface) periarterial spaces in mice are essentially open. (1) Paths of particles in the perivascular spaces are smooth, as expected for viscous flow in an open vessel, not diffusive, as expected for flow in a porous medium. (2) Time-averaged velocity profiles in periarterial spaces agree closely with theoretical profiles for viscous flow in realistic models, but not with the nearly uniform profiles expected for porous medium. Because these spaces are open, they have much lower hydraulic resistance than if they were porous. To demonstrate, we compute hydraulic resistance for realistic periarterial spaces, both open and porous, and show that the resistance of the porous spaces are greater, typically by a factor of a hundred or more. The open nature of these periarterial spaces allows significantly greater flow rates and more efficient removal of metabolic waste products.
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Affiliation(s)
- Fatima Min Rivas
- Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627, USA
| | - Jia Liu
- Department of Mechanical Engineering, University of Rochester, Rochester, NY 14627, USA
| | - Benjamin C Martell
- Department of Mechanical Engineering, University of Rochester, Rochester, NY 14627, USA.,Department of Aeronautics and Astronautics, Massachusetts Institute of Technology, Cambridge, MA 02142, USA
| | - Ting Du
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Humberto Mestre
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA.,Department of Neurology, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA.,Department of Neurology, University of Rochester Medical Center, Rochester, NY 14642, USA.,Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
| | - Jeffrey Tithof
- Department of Mechanical Engineering, University of Rochester, Rochester, NY 14627, USA.,Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
| | - John H Thomas
- Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627, USA.,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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414
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Tashima T. Shortcut Approaches to Substance Delivery into the Brain Based on Intranasal Administration Using Nanodelivery Strategies for Insulin. Molecules 2020; 25:E5188. [PMID: 33171799 PMCID: PMC7664636 DOI: 10.3390/molecules25215188] [Citation(s) in RCA: 29] [Impact Index Per Article: 7.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/04/2020] [Revised: 10/26/2020] [Accepted: 11/05/2020] [Indexed: 12/13/2022] Open
Abstract
The direct delivery of central nervous system (CNS) drugs into the brain after administration is an ideal concept due to its effectiveness and non-toxicity. However, the blood-brain barrier (BBB) prevents drugs from penetrating the capillary endothelial cells, blocking their entry into the brain. Thus, alternative approaches must be developed. The nasal cavity directly leads from the olfactory epithelium to the brain through the cribriform plate of the skull bone. Nose-to-brain drug delivery could solve the BBB-related repulsion problem. Recently, it has been revealed that insulin improved Alzheimer's disease (AD)-related dementia. Several ongoing AD clinical trials investigate the use of intranasal insulin delivery. Related to the real trajectory, intranasal labeled-insulins demonstrated distribution into the brain not only along the olfactory nerve but also the trigeminal nerve. Nonetheless, intranasally administered insulin was delivered into the brain. Therefore, insulin conjugates with covalent or non-covalent cargos, such as AD or other CNS drugs, could potentially contribute to a promising strategy to cure CNS-related diseases. In this review, I will introduce the CNS drug delivery approach into the brain using nanodelivery strategies for insulin through transcellular routes based on receptor-mediated transcytosis or through paracellular routes based on escaping the tight junction at the olfactory epithelium.
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Affiliation(s)
- Toshihiko Tashima
- Tashima Laboratories of Arts and Sciences, 1239-5 Toriyama-cho, Kohoku-ku, Yokohama, Kanagawa 222-0035, Japan
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415
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Eide PK, Pripp AH, Ringstad G. Magnetic resonance imaging biomarkers of cerebrospinal fluid tracer dynamics in idiopathic normal pressure hydrocephalus. Brain Commun 2020; 2:fcaa187. [PMID: 33381757 PMCID: PMC7753057 DOI: 10.1093/braincomms/fcaa187] [Citation(s) in RCA: 20] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/13/2020] [Revised: 09/09/2020] [Accepted: 09/22/2020] [Indexed: 12/14/2022] Open
Abstract
Disturbed clearance of toxic metabolites from the brain via cerebrospinal fluid is emerging as an important mechanism behind dementia and neurodegeneration. To this end, magnetic resonance imaging work-up of dementia diseases is largely focused on anatomical derangements of the brain. This study explores magnetic resonance imaging biomarkers of cerebrospinal fluid tracer dynamics in patients with the dementia subtype idiopathic normal pressure hydrocephalus and a cohort of reference subjects. All study participants underwent multi-phase magnetic resonance imaging up to 48 h after intrathecal administration of the contrast agent gadobutrol (0.5 ml, 1 mmol/ml), serving as cerebrospinal fluid tracer. Imaging biomarkers of cerebrospinal fluid tracer dynamics (i.e. ventricular reflux grades 0–4 and clearance) were compared with anatomical magnetic resonance imaging biomarkers of cerebrospinal fluid space anatomy (Evans’ index, callosal angle and disproportional enlargement of subarachnoid spaces hydrocephalus) and neurodegeneration (Schelten’s medial temporal atrophy scores, Fazeka’s scores and entorhinal cortex thickness). The imaging scores were also related to a pulsatile intracranial pressure score indicative of intracranial compliance. In shunt-responsive idiopathic normal pressure hydrocephalus, the imaging biomarkers demonstrated significantly altered cerebrospinal fluid tracer dynamics (ventricular reflux grades 3–4 and reduced clearance of tracer), deranged cerebrospinal fluid space anatomy and pronounced neurodegeneration. The altered MRI biomarkers were accompanied by pressure indices of impaired intracranial compliance. In conclusion, we present novel magnetic resonance imaging biomarkers characterizing idiopathic normal pressure hydrocephalus pathophysiology, namely measures of cerebrospinal fluid molecular redistribution and clearance, which add information to traditional imaging scores of cerebrospinal fluid space anatomy and neurodegeneration.
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Affiliation(s)
- Per Kristian Eide
- Department of Neurosurgery, Oslo University Hospital-Rikshospitalet, Oslo, Norway.,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Are H Pripp
- Oslo Centre of Biostatistics and Epidemiology, Oslo University Hospital, Oslo, Norway
| | - Geir Ringstad
- Department of Radiology, Oslo University Hospital- Rikshospitalet, Oslo, Norway
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416
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Kim SH, Ahn JH, Yang H, Lee P, Koh GY, Jeong Y. Cerebral amyloid angiopathy aggravates perivascular clearance impairment in an Alzheimer's disease mouse model. Acta Neuropathol Commun 2020; 8:181. [PMID: 33153499 PMCID: PMC7643327 DOI: 10.1186/s40478-020-01042-0] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/31/2020] [Accepted: 09/24/2020] [Indexed: 02/06/2023] Open
Abstract
Cerebral amyloid angiopathy (CAA), defined as the accumulation of amyloid-beta (Aβ) on the vascular wall, is a major pathology of Alzheimer’s disease (AD) and has been thought to be caused by the failure of Aβ clearance. Although two types of perivascular clearance mechanisms, intramural periarterial drainage (IPAD) and the perivascular cerebrospinal fluid (CSF) influx, have been identified, the exact contribution of CAA on perivascular clearance is still not well understood. In this study, we investigated the effect of CAA on the structure and function of perivascular clearance systems in the APP/PS1 transgenic mouse model. To investigate the pathological changes accompanied by CAA progression, the key elements of perivascular clearance such as the perivascular basement membrane, vascular smooth muscle cells (vSMCs), and vascular pulsation were evaluated in middle-aged (7–9 months) and old-aged (19–21 months) mice using in vivo imaging and immunofluorescence staining. Changes in IPAD and perivascular CSF influx were identified by ex vivo fluorescence imaging after dextran injection into the parenchyma or cisterna magna. Amyloid deposition on the vascular wall disrupted the integrity and morphology of the arterial basement membrane. With CAA progression, vascular pulsation was augmented, and conversely, vSMC coverage was decreased. These pathological changes were more pronounced in the surface arteries with earlier amyloid accumulation than in penetrating arteries. IPAD and perivascular CSF influx were impaired in the middle-aged APP/PS1 mice and further aggravated in old age, showing severely impaired tracer influx and efflux patterns. Reduced clearance was also observed in old wild-type mice without changing the tracer distribution pattern in the influx and efflux pathway. These findings suggest that CAA is not merely a consequence of perivascular clearance impairment, but rather a contributor to this process, causing changes in arterial function and structure and increasing AD severity.
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417
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Jacobsen HH, Sandell T, Jørstad ØK, Moe MC, Ringstad G, Eide PK. In Vivo Evidence for Impaired Glymphatic Function in the Visual Pathway of Patients With Normal Pressure Hydrocephalus. Invest Ophthalmol Vis Sci 2020; 61:24. [PMID: 33201186 PMCID: PMC7683855 DOI: 10.1167/iovs.61.13.24] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/11/2022] Open
Abstract
Purpose Impaired ability to remove toxic metabolites from central nervous system may be an important link between cerebral and ophthalmic degenerative diseases. The aim of the present study was to compare the glymphatic function in the visual pathway in patients with idiopathic normal pressure hydrocephalus (iNPH), a neurodegenerative dementia subtype, with a reference group. Methods We compared 31 subjects with Definite iNPH (i.e., shunt-responsive) with 13 references in a prospective and observational study. After intrathecal injection of the magnetic contrast agent gadobutrol (Gadovist, 0.5 mL, 1.0 mmol/mL, Bayer Pharma AG), serving as a tracer, consecutive magnetic resonance imaging (MRI) scans were obtained (next 24-48 hours). The normalized MRI T1 signal recorded in the cerebrospinal fluid (CSF) and along the visual pathway served as a semi-quantitative measure of tracer enrichment. Gadobutrol does not penetrate the blood-brain barrier and is thus confined to the extravascular space. Overnight measurements of pulsatile intracranial pressure were used as a surrogate marker for the intracranial compliance. Results The tracer enriched the prechiasmatic cistern similarly in both groups, but clearance was delayed in the iNPH group. Moreover, both delayed enrichment and clearance of the tracer were observed in the visual pathway in the iNPH subjects. The enrichment in the visual pathway and the CSF correlated. Individuals with elevated pulsatile intracranial pressure showed reduced enrichment within the visual pathway. Conclusions There was delayed enrichment and clearance of a tracer in the visual pathway of iNPH patients, which suggests impaired glymphatic function in the visual pathway in this disease.
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Affiliation(s)
- Henrik Holvin Jacobsen
- Department of Ophthalmology, Oslo University Hospital, Oslo, Norway.,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Tiril Sandell
- Department of Ophthalmology, Oslo University Hospital, Oslo, Norway.,Department of Ophthalmology, Vestre Viken Hospital, Drammen, Norway
| | | | - Morten C Moe
- Department of Ophthalmology, Oslo University Hospital, Oslo, Norway.,Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Geir Ringstad
- Division of Radiology and Nuclear Medicine, Department of Radiology, Oslo University Hospital-Rikshospitalet, Oslo, Norway
| | - Per Kristian Eide
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Neurosurgery, Oslo University Hospital-Rikshospitalet, Oslo, Norway
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418
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Ji Y, Li X, Teng Z, Li X, Jin W, Lv PY. Homocysteine is Associated with the Development of Cerebral Small Vessel Disease: Retrospective Analyses from Neuroimaging and Cognitive Outcomes. J Stroke Cerebrovasc Dis 2020; 29:105393. [PMID: 33254368 DOI: 10.1016/j.jstrokecerebrovasdis.2020.105393] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/13/2020] [Accepted: 10/04/2020] [Indexed: 01/01/2023] Open
Abstract
OBJECTIVE As the population ages, a growing burden of cerebral small vessel disease (cSVD) has sparked extensive concerns recently. Homocysteine (Hcy), as a traditional risk factor for atherosclerosis, may also participate in the development of cSVD. By comprehensively assessing Hcy's correlation with different MRI markers of cSVD and cognitive outcomes in a homogeneous population with cSVD, this study aims to explore the value of Hcy in the clinical management of cSVD. METHODS 231 inpatients with MRI-confirmed cSVD were enrolled in this retrospective study (mean age 66.4±10.0 years, male sex 47.6%). Along with brain MRI and plasma total Hcy (tHcy) examination, Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA) were also performed to assess their global cognitive function. Burdens of cSVD neuroimaging features encompassing white matter hyperintensity (WMH), lacunes of presumed vascular origin, cerebral microbleeds (CMBs), and enlarged perivascular spaces (EPVS) were evaluated based on brain MRI demonstrations. RESULTS After adjusting for possible confounders, statistical analyses showed that plasma tHcy levels were not only correlated with burdens of deep/periventricular WMH (P < 0.001, P for trend < 0.001; P < 0.001, P for trend < 0.001), lacunes (P < 0.001, P for trend < 0.001), lobar CMBs (P = 0.002), and EPVS in the basal ganglia (P < 0.001, P for trend = 0.002) but also remained an independent predictor of cognitive impairment (B=-0.159, 95%CI -0.269--0.049, P = 0.005, P for trend < 0.001) in the patients with cSVD. CONCLUSIONS Plasma tHcy levels are associated with the development of cSVD in a dose-independent manner and may predict the cognitive outcomes in cSVD patients. These findings provide a potential clue to cSVD's physiopathology and future disease management.
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Affiliation(s)
- Yifan Ji
- Neurology Department, Hebei General Hospital, Shijiazhuang 050051, PR China; Graduate School of Hebei Medical University, Shijiazhuang 050017, PR China
| | - Xiangyu Li
- Neurology Department, Hebei General Hospital, Shijiazhuang 050051, PR China; Graduate School of Hebei Medical University, Shijiazhuang 050017, PR China
| | - Zhenjie Teng
- Neurology Department, Hebei General Hospital, Shijiazhuang 050051, PR China
| | - Xiaosha Li
- Neurology Department, Hebei General Hospital, Shijiazhuang 050051, PR China; Graduate School of Hebei Medical University, Shijiazhuang 050017, PR China
| | - Wei Jin
- Neurology Department, Hebei General Hospital, Shijiazhuang 050051, PR China
| | - Pei Yuan Lv
- Neurology Department, Hebei General Hospital, Shijiazhuang 050051, PR China; Graduate School of Hebei Medical University, Shijiazhuang 050017, PR China.
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419
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Hennig J, Kiviniemi V, Riemenschneider B, Barghoorn A, Akin B, Wang F, LeVan P. 15 Years MR-encephalography. MAGNETIC RESONANCE MATERIALS IN PHYSICS BIOLOGY AND MEDICINE 2020; 34:85-108. [PMID: 33079327 PMCID: PMC7910380 DOI: 10.1007/s10334-020-00891-z] [Citation(s) in RCA: 11] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Revised: 09/02/2020] [Accepted: 09/29/2020] [Indexed: 02/07/2023]
Abstract
Objective This review article gives an account of the development of the MR-encephalography (MREG) method, which started as a mere ‘Gedankenexperiment’ in 2005 and gradually developed into a method for ultrafast measurement of physiological activities in the brain. After going through different approaches covering k-space with radial, rosette, and concentric shell trajectories we have settled on a stack-of-spiral trajectory, which allows full brain coverage with (nominal) 3 mm isotropic resolution in 100 ms. The very high acceleration factor is facilitated by the near-isotropic k-space coverage, which allows high acceleration in all three spatial dimensions. Methods The methodological section covers the basic sequence design as well as recent advances in image reconstruction including the targeted reconstruction, which allows real-time feedback applications, and—most recently—the time-domain principal component reconstruction (tPCR), which applies a principal component analysis of the acquired time domain data as a sparsifying transformation to improve reconstruction speed as well as quality. Applications Although the BOLD-response is rather slow, the high speed acquisition of MREG allows separation of BOLD-effects from cardiac and breathing related pulsatility. The increased sensitivity enables direct detection of the dynamic variability of resting state networks as well as localization of single interictal events in epilepsy patients. A separate and highly intriguing application is aimed at the investigation of the glymphatic system by assessment of the spatiotemporal patterns of cardiac and breathing related pulsatility. Discussion MREG has been developed to push the speed limits of fMRI. Compared to multiband-EPI this allows considerably faster acquisition at the cost of reduced image quality and spatial resolution.
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Affiliation(s)
- Juergen Hennig
- Department of Radiology, Medical Physics, Faculty of Medicine, Medical Center University of Freiburg, University of Freiburg, Freiburg, Germany. .,Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany.
| | - Vesa Kiviniemi
- Oulu Functional NeuroImaging Group, Research Unit of Medical Imaging, Physics and Technology, University of Oulu, Oulu, Finland
| | - Bruno Riemenschneider
- Department of Radiology, Center for Biomedical Imaging, New York University Grossman School of Medicine, New York, NY, USA
| | - Antonia Barghoorn
- Department of Radiology, Medical Physics, Faculty of Medicine, Medical Center University of Freiburg, University of Freiburg, Freiburg, Germany.,Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Burak Akin
- Department of Radiology, Medical Physics, Faculty of Medicine, Medical Center University of Freiburg, University of Freiburg, Freiburg, Germany.,Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Fei Wang
- Department of Radiology, Medical Physics, Faculty of Medicine, Medical Center University of Freiburg, University of Freiburg, Freiburg, Germany.,Center for Basics in NeuroModulation (NeuroModulBasics), Faculty of Medicine, University of Freiburg, Freiburg, Germany
| | - Pierre LeVan
- Departments of Radiology and Paediatrics, Hotchkiss Brain Institute and Alberta Children's Hospital Research Institute, University of Calgary, Calgary, AB, Canada
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420
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Best JG, Barbato C, Ambler G, Du H, Banerjee G, Wilson D, Shakeshaft C, Cohen H, Yousry TA, Al-Shahi Salman R, Lip GYH, Houlden H, Brown MM, Muir KW, Jäger HR, Werring DJ. Association of enlarged perivascular spaces and anticoagulant-related intracranial hemorrhage. Neurology 2020; 95:e2192-e2199. [PMID: 32934168 PMCID: PMC7713790 DOI: 10.1212/wnl.0000000000010788] [Citation(s) in RCA: 22] [Impact Index Per Article: 5.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/19/2019] [Accepted: 05/11/2020] [Indexed: 01/08/2023] Open
Abstract
OBJECTIVE To investigate whether enlarged perivascular spaces (PVS) within the basal ganglia or deep cerebral white matter are risk factors for intracranial hemorrhage in patients taking oral anticoagulants (OACs), independent of established clinical and radiologic risk factors, we conducted a post hoc analysis of Clinical Relevance of Microbleeds in Stroke (CROMIS-2) (atrial fibrillation [AF]), a prospective inception cohort study. METHODS Patients with atrial fibrillation and recent TIA or ischemic stroke underwent standardized MRI prior to starting OAC. We rated basal ganglia PVS (BGPVS) and centrum semiovale PVS (CSOPVS), cerebral microbleeds (CMBs), white matter hyperintensities, and lacunes. We dichotomized the PVS rating using a threshold of >10 PVS in the relevant region of either cerebral hemisphere. The primary outcome was symptomatic intracranial hemorrhage (sICH). We identified risk factors for sICH using Cox regression. RESULTS A total of 1,386 participants with available clinical and imaging variables were followed up for a mean of 2.34 years; 14 sICH occurred (11 intracerebral). In univariable analysis, diabetes, CMB presence, lacune presence, and >10 BGPVS, but not CSOPVS, were associated with sICH. In a multivariable model incorporating all variables with significant associations in univariable analysis, >10 BGPVS (hazard ratio [HR] 8.96, 95% [CI] 2.41-33.4, p = 0.001) and diabetes (HR 3.91, 95% CI 1.34-11.4) remained significant risk factors for sICH. CONCLUSION Enlarged BGPVS might be a novel risk factor for OAC-related ICH. The strength of this association and potential use in predicting ICH in clinical practice should be investigated in larger cohorts.
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Affiliation(s)
- Jonathan G Best
- From the Stroke Research Center (J.G.B., C.B., H.D., G.B., D.W., C.S., M.M.B., D.J.W.) and Lysholm Department of Neuroradiology and the Neuroradiological Academic Unit (T.A.Y., H.R.J.), Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology; Department of Statistical Science (G.A.), Haemostasis Research Unit, Department of Haematology (H.C.), University College London, UK; Stroke Research Center, Department of Neurology (H.D.), Fujian Medical University Union Hospital, Fuzhou, China; Center for Clinical Brain Sciences, School of Clinical Sciences (R.A.-S.S.), University of Edinburgh; Liverpool Center for Cardiovascular Science (G.Y.H.L.), University of Liverpool and Liverpool Heart and Chest Hospital, UK; Aalborg Thrombosis Research Unit, Department of Clinical Medicine (G.Y.H.L.), Aalborg University, Denmark; Department of Molecular Neuroscience (H.H.), UCL Queen Square Institute of Neurology and the National Hospital for Neurology and Neurosurgery, London; and Institute of Neuroscience & Psychology (K.W.M.), University of Glasgow, Queen Elizabeth University Hospital, UK
| | - Carmen Barbato
- From the Stroke Research Center (J.G.B., C.B., H.D., G.B., D.W., C.S., M.M.B., D.J.W.) and Lysholm Department of Neuroradiology and the Neuroradiological Academic Unit (T.A.Y., H.R.J.), Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology; Department of Statistical Science (G.A.), Haemostasis Research Unit, Department of Haematology (H.C.), University College London, UK; Stroke Research Center, Department of Neurology (H.D.), Fujian Medical University Union Hospital, Fuzhou, China; Center for Clinical Brain Sciences, School of Clinical Sciences (R.A.-S.S.), University of Edinburgh; Liverpool Center for Cardiovascular Science (G.Y.H.L.), University of Liverpool and Liverpool Heart and Chest Hospital, UK; Aalborg Thrombosis Research Unit, Department of Clinical Medicine (G.Y.H.L.), Aalborg University, Denmark; Department of Molecular Neuroscience (H.H.), UCL Queen Square Institute of Neurology and the National Hospital for Neurology and Neurosurgery, London; and Institute of Neuroscience & Psychology (K.W.M.), University of Glasgow, Queen Elizabeth University Hospital, UK
| | - Gareth Ambler
- From the Stroke Research Center (J.G.B., C.B., H.D., G.B., D.W., C.S., M.M.B., D.J.W.) and Lysholm Department of Neuroradiology and the Neuroradiological Academic Unit (T.A.Y., H.R.J.), Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology; Department of Statistical Science (G.A.), Haemostasis Research Unit, Department of Haematology (H.C.), University College London, UK; Stroke Research Center, Department of Neurology (H.D.), Fujian Medical University Union Hospital, Fuzhou, China; Center for Clinical Brain Sciences, School of Clinical Sciences (R.A.-S.S.), University of Edinburgh; Liverpool Center for Cardiovascular Science (G.Y.H.L.), University of Liverpool and Liverpool Heart and Chest Hospital, UK; Aalborg Thrombosis Research Unit, Department of Clinical Medicine (G.Y.H.L.), Aalborg University, Denmark; Department of Molecular Neuroscience (H.H.), UCL Queen Square Institute of Neurology and the National Hospital for Neurology and Neurosurgery, London; and Institute of Neuroscience & Psychology (K.W.M.), University of Glasgow, Queen Elizabeth University Hospital, UK
| | - Houwei Du
- From the Stroke Research Center (J.G.B., C.B., H.D., G.B., D.W., C.S., M.M.B., D.J.W.) and Lysholm Department of Neuroradiology and the Neuroradiological Academic Unit (T.A.Y., H.R.J.), Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology; Department of Statistical Science (G.A.), Haemostasis Research Unit, Department of Haematology (H.C.), University College London, UK; Stroke Research Center, Department of Neurology (H.D.), Fujian Medical University Union Hospital, Fuzhou, China; Center for Clinical Brain Sciences, School of Clinical Sciences (R.A.-S.S.), University of Edinburgh; Liverpool Center for Cardiovascular Science (G.Y.H.L.), University of Liverpool and Liverpool Heart and Chest Hospital, UK; Aalborg Thrombosis Research Unit, Department of Clinical Medicine (G.Y.H.L.), Aalborg University, Denmark; Department of Molecular Neuroscience (H.H.), UCL Queen Square Institute of Neurology and the National Hospital for Neurology and Neurosurgery, London; and Institute of Neuroscience & Psychology (K.W.M.), University of Glasgow, Queen Elizabeth University Hospital, UK
| | - Gargi Banerjee
- From the Stroke Research Center (J.G.B., C.B., H.D., G.B., D.W., C.S., M.M.B., D.J.W.) and Lysholm Department of Neuroradiology and the Neuroradiological Academic Unit (T.A.Y., H.R.J.), Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology; Department of Statistical Science (G.A.), Haemostasis Research Unit, Department of Haematology (H.C.), University College London, UK; Stroke Research Center, Department of Neurology (H.D.), Fujian Medical University Union Hospital, Fuzhou, China; Center for Clinical Brain Sciences, School of Clinical Sciences (R.A.-S.S.), University of Edinburgh; Liverpool Center for Cardiovascular Science (G.Y.H.L.), University of Liverpool and Liverpool Heart and Chest Hospital, UK; Aalborg Thrombosis Research Unit, Department of Clinical Medicine (G.Y.H.L.), Aalborg University, Denmark; Department of Molecular Neuroscience (H.H.), UCL Queen Square Institute of Neurology and the National Hospital for Neurology and Neurosurgery, London; and Institute of Neuroscience & Psychology (K.W.M.), University of Glasgow, Queen Elizabeth University Hospital, UK
| | - Duncan Wilson
- From the Stroke Research Center (J.G.B., C.B., H.D., G.B., D.W., C.S., M.M.B., D.J.W.) and Lysholm Department of Neuroradiology and the Neuroradiological Academic Unit (T.A.Y., H.R.J.), Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology; Department of Statistical Science (G.A.), Haemostasis Research Unit, Department of Haematology (H.C.), University College London, UK; Stroke Research Center, Department of Neurology (H.D.), Fujian Medical University Union Hospital, Fuzhou, China; Center for Clinical Brain Sciences, School of Clinical Sciences (R.A.-S.S.), University of Edinburgh; Liverpool Center for Cardiovascular Science (G.Y.H.L.), University of Liverpool and Liverpool Heart and Chest Hospital, UK; Aalborg Thrombosis Research Unit, Department of Clinical Medicine (G.Y.H.L.), Aalborg University, Denmark; Department of Molecular Neuroscience (H.H.), UCL Queen Square Institute of Neurology and the National Hospital for Neurology and Neurosurgery, London; and Institute of Neuroscience & Psychology (K.W.M.), University of Glasgow, Queen Elizabeth University Hospital, UK
| | - Clare Shakeshaft
- From the Stroke Research Center (J.G.B., C.B., H.D., G.B., D.W., C.S., M.M.B., D.J.W.) and Lysholm Department of Neuroradiology and the Neuroradiological Academic Unit (T.A.Y., H.R.J.), Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology; Department of Statistical Science (G.A.), Haemostasis Research Unit, Department of Haematology (H.C.), University College London, UK; Stroke Research Center, Department of Neurology (H.D.), Fujian Medical University Union Hospital, Fuzhou, China; Center for Clinical Brain Sciences, School of Clinical Sciences (R.A.-S.S.), University of Edinburgh; Liverpool Center for Cardiovascular Science (G.Y.H.L.), University of Liverpool and Liverpool Heart and Chest Hospital, UK; Aalborg Thrombosis Research Unit, Department of Clinical Medicine (G.Y.H.L.), Aalborg University, Denmark; Department of Molecular Neuroscience (H.H.), UCL Queen Square Institute of Neurology and the National Hospital for Neurology and Neurosurgery, London; and Institute of Neuroscience & Psychology (K.W.M.), University of Glasgow, Queen Elizabeth University Hospital, UK
| | - Hannah Cohen
- From the Stroke Research Center (J.G.B., C.B., H.D., G.B., D.W., C.S., M.M.B., D.J.W.) and Lysholm Department of Neuroradiology and the Neuroradiological Academic Unit (T.A.Y., H.R.J.), Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology; Department of Statistical Science (G.A.), Haemostasis Research Unit, Department of Haematology (H.C.), University College London, UK; Stroke Research Center, Department of Neurology (H.D.), Fujian Medical University Union Hospital, Fuzhou, China; Center for Clinical Brain Sciences, School of Clinical Sciences (R.A.-S.S.), University of Edinburgh; Liverpool Center for Cardiovascular Science (G.Y.H.L.), University of Liverpool and Liverpool Heart and Chest Hospital, UK; Aalborg Thrombosis Research Unit, Department of Clinical Medicine (G.Y.H.L.), Aalborg University, Denmark; Department of Molecular Neuroscience (H.H.), UCL Queen Square Institute of Neurology and the National Hospital for Neurology and Neurosurgery, London; and Institute of Neuroscience & Psychology (K.W.M.), University of Glasgow, Queen Elizabeth University Hospital, UK
| | - Tarek A Yousry
- From the Stroke Research Center (J.G.B., C.B., H.D., G.B., D.W., C.S., M.M.B., D.J.W.) and Lysholm Department of Neuroradiology and the Neuroradiological Academic Unit (T.A.Y., H.R.J.), Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology; Department of Statistical Science (G.A.), Haemostasis Research Unit, Department of Haematology (H.C.), University College London, UK; Stroke Research Center, Department of Neurology (H.D.), Fujian Medical University Union Hospital, Fuzhou, China; Center for Clinical Brain Sciences, School of Clinical Sciences (R.A.-S.S.), University of Edinburgh; Liverpool Center for Cardiovascular Science (G.Y.H.L.), University of Liverpool and Liverpool Heart and Chest Hospital, UK; Aalborg Thrombosis Research Unit, Department of Clinical Medicine (G.Y.H.L.), Aalborg University, Denmark; Department of Molecular Neuroscience (H.H.), UCL Queen Square Institute of Neurology and the National Hospital for Neurology and Neurosurgery, London; and Institute of Neuroscience & Psychology (K.W.M.), University of Glasgow, Queen Elizabeth University Hospital, UK
| | - Rustam Al-Shahi Salman
- From the Stroke Research Center (J.G.B., C.B., H.D., G.B., D.W., C.S., M.M.B., D.J.W.) and Lysholm Department of Neuroradiology and the Neuroradiological Academic Unit (T.A.Y., H.R.J.), Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology; Department of Statistical Science (G.A.), Haemostasis Research Unit, Department of Haematology (H.C.), University College London, UK; Stroke Research Center, Department of Neurology (H.D.), Fujian Medical University Union Hospital, Fuzhou, China; Center for Clinical Brain Sciences, School of Clinical Sciences (R.A.-S.S.), University of Edinburgh; Liverpool Center for Cardiovascular Science (G.Y.H.L.), University of Liverpool and Liverpool Heart and Chest Hospital, UK; Aalborg Thrombosis Research Unit, Department of Clinical Medicine (G.Y.H.L.), Aalborg University, Denmark; Department of Molecular Neuroscience (H.H.), UCL Queen Square Institute of Neurology and the National Hospital for Neurology and Neurosurgery, London; and Institute of Neuroscience & Psychology (K.W.M.), University of Glasgow, Queen Elizabeth University Hospital, UK
| | - Gregory Y H Lip
- From the Stroke Research Center (J.G.B., C.B., H.D., G.B., D.W., C.S., M.M.B., D.J.W.) and Lysholm Department of Neuroradiology and the Neuroradiological Academic Unit (T.A.Y., H.R.J.), Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology; Department of Statistical Science (G.A.), Haemostasis Research Unit, Department of Haematology (H.C.), University College London, UK; Stroke Research Center, Department of Neurology (H.D.), Fujian Medical University Union Hospital, Fuzhou, China; Center for Clinical Brain Sciences, School of Clinical Sciences (R.A.-S.S.), University of Edinburgh; Liverpool Center for Cardiovascular Science (G.Y.H.L.), University of Liverpool and Liverpool Heart and Chest Hospital, UK; Aalborg Thrombosis Research Unit, Department of Clinical Medicine (G.Y.H.L.), Aalborg University, Denmark; Department of Molecular Neuroscience (H.H.), UCL Queen Square Institute of Neurology and the National Hospital for Neurology and Neurosurgery, London; and Institute of Neuroscience & Psychology (K.W.M.), University of Glasgow, Queen Elizabeth University Hospital, UK
| | - Henry Houlden
- From the Stroke Research Center (J.G.B., C.B., H.D., G.B., D.W., C.S., M.M.B., D.J.W.) and Lysholm Department of Neuroradiology and the Neuroradiological Academic Unit (T.A.Y., H.R.J.), Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology; Department of Statistical Science (G.A.), Haemostasis Research Unit, Department of Haematology (H.C.), University College London, UK; Stroke Research Center, Department of Neurology (H.D.), Fujian Medical University Union Hospital, Fuzhou, China; Center for Clinical Brain Sciences, School of Clinical Sciences (R.A.-S.S.), University of Edinburgh; Liverpool Center for Cardiovascular Science (G.Y.H.L.), University of Liverpool and Liverpool Heart and Chest Hospital, UK; Aalborg Thrombosis Research Unit, Department of Clinical Medicine (G.Y.H.L.), Aalborg University, Denmark; Department of Molecular Neuroscience (H.H.), UCL Queen Square Institute of Neurology and the National Hospital for Neurology and Neurosurgery, London; and Institute of Neuroscience & Psychology (K.W.M.), University of Glasgow, Queen Elizabeth University Hospital, UK
| | - Martin M Brown
- From the Stroke Research Center (J.G.B., C.B., H.D., G.B., D.W., C.S., M.M.B., D.J.W.) and Lysholm Department of Neuroradiology and the Neuroradiological Academic Unit (T.A.Y., H.R.J.), Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology; Department of Statistical Science (G.A.), Haemostasis Research Unit, Department of Haematology (H.C.), University College London, UK; Stroke Research Center, Department of Neurology (H.D.), Fujian Medical University Union Hospital, Fuzhou, China; Center for Clinical Brain Sciences, School of Clinical Sciences (R.A.-S.S.), University of Edinburgh; Liverpool Center for Cardiovascular Science (G.Y.H.L.), University of Liverpool and Liverpool Heart and Chest Hospital, UK; Aalborg Thrombosis Research Unit, Department of Clinical Medicine (G.Y.H.L.), Aalborg University, Denmark; Department of Molecular Neuroscience (H.H.), UCL Queen Square Institute of Neurology and the National Hospital for Neurology and Neurosurgery, London; and Institute of Neuroscience & Psychology (K.W.M.), University of Glasgow, Queen Elizabeth University Hospital, UK
| | - Keith W Muir
- From the Stroke Research Center (J.G.B., C.B., H.D., G.B., D.W., C.S., M.M.B., D.J.W.) and Lysholm Department of Neuroradiology and the Neuroradiological Academic Unit (T.A.Y., H.R.J.), Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology; Department of Statistical Science (G.A.), Haemostasis Research Unit, Department of Haematology (H.C.), University College London, UK; Stroke Research Center, Department of Neurology (H.D.), Fujian Medical University Union Hospital, Fuzhou, China; Center for Clinical Brain Sciences, School of Clinical Sciences (R.A.-S.S.), University of Edinburgh; Liverpool Center for Cardiovascular Science (G.Y.H.L.), University of Liverpool and Liverpool Heart and Chest Hospital, UK; Aalborg Thrombosis Research Unit, Department of Clinical Medicine (G.Y.H.L.), Aalborg University, Denmark; Department of Molecular Neuroscience (H.H.), UCL Queen Square Institute of Neurology and the National Hospital for Neurology and Neurosurgery, London; and Institute of Neuroscience & Psychology (K.W.M.), University of Glasgow, Queen Elizabeth University Hospital, UK
| | - Hans Rolf Jäger
- From the Stroke Research Center (J.G.B., C.B., H.D., G.B., D.W., C.S., M.M.B., D.J.W.) and Lysholm Department of Neuroradiology and the Neuroradiological Academic Unit (T.A.Y., H.R.J.), Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology; Department of Statistical Science (G.A.), Haemostasis Research Unit, Department of Haematology (H.C.), University College London, UK; Stroke Research Center, Department of Neurology (H.D.), Fujian Medical University Union Hospital, Fuzhou, China; Center for Clinical Brain Sciences, School of Clinical Sciences (R.A.-S.S.), University of Edinburgh; Liverpool Center for Cardiovascular Science (G.Y.H.L.), University of Liverpool and Liverpool Heart and Chest Hospital, UK; Aalborg Thrombosis Research Unit, Department of Clinical Medicine (G.Y.H.L.), Aalborg University, Denmark; Department of Molecular Neuroscience (H.H.), UCL Queen Square Institute of Neurology and the National Hospital for Neurology and Neurosurgery, London; and Institute of Neuroscience & Psychology (K.W.M.), University of Glasgow, Queen Elizabeth University Hospital, UK
| | - David J Werring
- From the Stroke Research Center (J.G.B., C.B., H.D., G.B., D.W., C.S., M.M.B., D.J.W.) and Lysholm Department of Neuroradiology and the Neuroradiological Academic Unit (T.A.Y., H.R.J.), Department of Brain Repair and Rehabilitation, UCL Queen Square Institute of Neurology; Department of Statistical Science (G.A.), Haemostasis Research Unit, Department of Haematology (H.C.), University College London, UK; Stroke Research Center, Department of Neurology (H.D.), Fujian Medical University Union Hospital, Fuzhou, China; Center for Clinical Brain Sciences, School of Clinical Sciences (R.A.-S.S.), University of Edinburgh; Liverpool Center for Cardiovascular Science (G.Y.H.L.), University of Liverpool and Liverpool Heart and Chest Hospital, UK; Aalborg Thrombosis Research Unit, Department of Clinical Medicine (G.Y.H.L.), Aalborg University, Denmark; Department of Molecular Neuroscience (H.H.), UCL Queen Square Institute of Neurology and the National Hospital for Neurology and Neurosurgery, London; and Institute of Neuroscience & Psychology (K.W.M.), University of Glasgow, Queen Elizabeth University Hospital, UK.
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421
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Wang MX, Ray L, Tanaka KF, Iliff JJ, Heys J. Varying perivascular astroglial endfoot dimensions along the vascular tree maintain perivascular-interstitial flux through the cortical mantle. Glia 2020; 69:715-728. [PMID: 33075175 DOI: 10.1002/glia.23923] [Citation(s) in RCA: 26] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/12/2020] [Revised: 09/17/2020] [Accepted: 10/02/2020] [Indexed: 12/18/2022]
Abstract
The glymphatic system is a recently defined brain-wide network of perivascular spaces along which cerebrospinal fluid (CSF) and interstitial solutes exchange. Astrocyte endfeet encircling the perivascular space form a physical barrier in between these two compartments, and fluid and solutes that are not taken up by astrocytes move out of the perivascular space through the junctions in between astrocyte endfeet. However, little is known about the anatomical structure and the physiological roles of the astrocyte endfeet in regulating the local perivascular exchange. Here, visualizing astrocyte endfoot-endfoot junctions with immunofluorescent labeling against the protein megalencephalic leukoencephalopathy with subcortical cysts-1 (MLC1), we characterized endfoot dimensions along the mouse cerebrovascular tree. We observed marked heterogeneity in endfoot dimensions along vessels of different sizes, and of different types. Specifically, endfoot size was positively correlated with the vessel diameters, with large vessel segments surrounded by large endfeet and small vessel segments surrounded by small endfeet. This association was most pronounced along arterial, rather than venous segments. Computational modeling simulating vascular trees with uniform or varying endfeet dimensions demonstrates that varying endfoot dimensions maintain near constant perivascular-interstitial flux despite correspondingly declining perivascular pressures along the cerebrovascular tree through the cortical depth. These results describe a novel anatomical feature of perivascular astroglial endfeet and suggest that endfoot heterogeneity may be an evolutionary adaptation to maintain perivascular CSF-interstitial fluid exchange through deep brain structures.
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Affiliation(s)
- Marie Xun Wang
- VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), VA Puget Sound Health Care System, Seattle, Washington, USA.,Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, Washington, USA
| | - Lori Ray
- Department of Chemical and Biological Engineering, Montana State University-Bozeman, Bozeman, Montana, USA
| | - Kenji F Tanaka
- Department of Neuropsychiatry, Keio University School of Medicine, Tokyo, Japan
| | - Jeffrey J Iliff
- VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), VA Puget Sound Health Care System, Seattle, Washington, USA.,Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, Washington, USA.,Department of Neurology, University of Washington School of Medicine, Seattle, Washington, USA
| | - Jeffrey Heys
- Department of Chemical and Biological Engineering, Montana State University-Bozeman, Bozeman, Montana, USA
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422
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Bryniarski MA, Ren T, Rizvi AR, Snyder AM, Morris ME. Targeting the Choroid Plexuses for Protein Drug Delivery. Pharmaceutics 2020; 12:pharmaceutics12100963. [PMID: 33066423 PMCID: PMC7602164 DOI: 10.3390/pharmaceutics12100963] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/12/2020] [Revised: 10/05/2020] [Accepted: 10/10/2020] [Indexed: 12/15/2022] Open
Abstract
Delivery of therapeutic agents to the central nervous system is challenged by the barriers in place to regulate brain homeostasis. This is especially true for protein therapeutics. Targeting the barrier formed by the choroid plexuses at the interfaces of the systemic circulation and ventricular system may be a surrogate brain delivery strategy to circumvent the blood-brain barrier. Heterogenous cell populations located at the choroid plexuses provide diverse functions in regulating the exchange of material within the ventricular space. Receptor-mediated transcytosis may be a promising mechanism to deliver protein therapeutics across the tight junctions formed by choroid plexus epithelial cells. However, cerebrospinal fluid flow and other barriers formed by ependymal cells and perivascular spaces should also be considered for evaluation of protein therapeutic disposition. Various preclinical methods have been applied to delineate protein transport across the choroid plexuses, including imaging strategies, ventriculocisternal perfusions, and primary choroid plexus epithelial cell models. When used in combination with simultaneous measures of cerebrospinal fluid dynamics, they can yield important insight into pharmacokinetic properties within the brain. This review aims to provide an overview of the choroid plexuses and ventricular system to address their function as a barrier to pharmaceutical interventions and relevance for central nervous system drug delivery of protein therapeutics. Protein therapeutics targeting the ventricular system may provide new approaches in treating central nervous system diseases.
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423
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Soria FN, Miguelez C, Peñagarikano O, Tønnesen J. Current Techniques for Investigating the Brain Extracellular Space. Front Neurosci 2020; 14:570750. [PMID: 33177979 PMCID: PMC7591815 DOI: 10.3389/fnins.2020.570750] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2020] [Accepted: 09/17/2020] [Indexed: 12/11/2022] Open
Abstract
The brain extracellular space (ECS) is a continuous reticular compartment that lies between the cells of the brain. It is vast in extent relative to its resident cells, yet, at the same time the nano- to micrometer dimensions of its channels and reservoirs are commonly finer than the smallest cellular structures. Our conventional view of this compartment as largely static and of secondary importance for brain function is rapidly changing, and its active dynamic roles in signaling and metabolite clearance have come to the fore. It is further emerging that ECS microarchitecture is highly heterogeneous and dynamic and that ECS geometry and diffusional properties directly modulate local diffusional transport, down to the nanoscale around individual synapses. The ECS can therefore be considered an extremely complex and diverse compartment, where numerous physiological events are unfolding in parallel on spatial and temporal scales that span orders of magnitude, from milliseconds to hours, and from nanometers to centimeters. To further understand the physiological roles of the ECS and identify new ones, researchers can choose from a wide array of experimental techniques, which differ greatly in their applicability to a given sample and the type of data they produce. Here, we aim to provide a basic introduction to the available experimental techniques that have been applied to address the brain ECS, highlighting their main characteristics. We include current gold-standard techniques, as well as emerging cutting-edge modalities based on recent super-resolution microscopy. It is clear that each technique comes with unique strengths and limitations and that no single experimental method can unravel the unknown physiological roles of the brain ECS on its own.
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Affiliation(s)
- Federico N. Soria
- Achucarro Basque Center for Neuroscience, Leioa, Spain
- Department of Neuroscience, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), Leioa, Spain
| | - Cristina Miguelez
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), Leioa, Spain
- Autonomic and Movement Disorders Unit, Neurodegenerative Diseases, Biocruces Health Research Institute, Barakaldo, Spain
| | - Olga Peñagarikano
- Department of Pharmacology, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), Leioa, Spain
| | - Jan Tønnesen
- Achucarro Basque Center for Neuroscience, Leioa, Spain
- Department of Neuroscience, Faculty of Medicine and Nursing, University of the Basque Country (UPV/EHU), Leioa, Spain
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424
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Abstract
Sleep is evolutionarily conserved across all species, and impaired sleep is a common trait of the diseased brain. Sleep quality decreases as we age, and disruption of the regular sleep architecture is a frequent antecedent to the onset of dementia in neurodegenerative diseases. The glymphatic system, which clears the brain of protein waste products, is mostly active during sleep. Yet the glymphatic system degrades with age, suggesting a causal relationship between sleep disturbance and symptomatic progression in the neurodegenerative dementias. The ties that bind sleep, aging, glymphatic clearance, and protein aggregation have shed new light on the pathogenesis of a broad range of neurodegenerative diseases, for which glymphatic failure may constitute a therapeutically targetable final common pathway.
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Affiliation(s)
- Maiken Nedergaard
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark.
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
| | - Steven A Goldman
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark.
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY 14642, USA
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425
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Bèchet NB, Kylkilahti TM, Mattsson B, Petrasova M, Shanbhag NC, Lundgaard I. Light sheet fluorescence microscopy of optically cleared brains for studying the glymphatic system. J Cereb Blood Flow Metab 2020; 40:1975-1986. [PMID: 32525440 PMCID: PMC7786847 DOI: 10.1177/0271678x20924954] [Citation(s) in RCA: 19] [Impact Index Per Article: 4.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/06/2020] [Revised: 04/14/2020] [Accepted: 04/14/2020] [Indexed: 11/15/2022]
Abstract
Fluid transport in the perivascular space by the glia-lymphatic (glymphatic) system is important for the removal of solutes from the brain parenchyma, including peptides such as amyloid-beta which are implicated in the pathogenesis of Alzheimer's disease. The glymphatic system is highly active in the sleep state and under the influence of certain of anaesthetics, while it is suppressed in the awake state and by other anaesthetics. Here we investigated whether light sheet fluorescence microscopy of whole optically cleared murine brains was capable of detecting glymphatic differences in sleep- and awake-mimicking anaesthesia, respectively. Using light-sheet imaging of whole brains, we found anaesthetic-dependent cerebrospinal fluid (CSF) influx differences, including reduced tracer influx along tertiary branches of the middle cerebral artery and reduced influx along dorsal and anterior penetrating arterioles, in the awake-mimicking anaesthesia. This study establishes that light sheet microscopy of optically cleared brains is feasible for quantitative analyses and can provide images of the entire glymphatic system in whole brains.
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Affiliation(s)
- Nicholas B Bèchet
- Department of Experimental Medical Science, Lund University, Lund, Sweden
- Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden
| | - Tekla M Kylkilahti
- Department of Experimental Medical Science, Lund University, Lund, Sweden
- Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden
| | - Bengt Mattsson
- Developmental and Regenerative Neurobiology, Wallenberg Neuroscience Center, Lund University, Lund, Sweden
| | - Martina Petrasova
- Department of Experimental Medical Science, Lund University, Lund, Sweden
- Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden
- Department of Neurology, University Hospital Brno, Brno, Czech Republic
| | - Nagesh C Shanbhag
- Department of Experimental Medical Science, Lund University, Lund, Sweden
- Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden
| | - Iben Lundgaard
- Department of Experimental Medical Science, Lund University, Lund, Sweden
- Wallenberg Centre for Molecular Medicine, Lund University, Lund, Sweden
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426
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Liu X, Hao J, Yao E, Cao J, Zheng X, Yao D, Zhang C, Li J, Pan D, Luo X, Wang M, Wang W. Polyunsaturated fatty acid supplement alleviates depression-incident cognitive dysfunction by protecting the cerebrovascular and glymphatic systems. Brain Behav Immun 2020; 89:357-370. [PMID: 32717402 DOI: 10.1016/j.bbi.2020.07.022] [Citation(s) in RCA: 46] [Impact Index Per Article: 11.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/07/2020] [Revised: 06/20/2020] [Accepted: 07/19/2020] [Indexed: 01/25/2023] Open
Abstract
INTRODUCTION Depression, the most prevalent mood disorder, has high comorbidity with cerebrovascular disease and cognitive decline. However, there is little understanding of the cellular mechanisms involved in depression and its comorbid cerebrovascular damage and cognition impairment. Here, we tested the prediction that the chronic unpredictable mild stress (CUMS) mouse model would manifest in disturbed glymphatic function and that dietary supplementation with polyunsaturated fatty acids (PUFA) could ameliorate these deficits while alleviating the depression-associated cognitive decline. METHODS To test the treatment effects of PUFA or Es on behaviours, we applied the tail suspension, open field, and sucrose preference tests to assess depressive symptoms, and applied the Morris water maze test to assess cognition in groups of control, chronic unpredictable mild stress (CUMS), PUFA, and escitalopram (Es) treatment. We measured the extracellular concentrations of dopamine (DA), 5-hydroxytryptamine (5-HT) and noradrenaline (NA) in microdialysates from prefrontal cortex (PFC) by liquid chromatography mass spectrometry. Glia cells and inflammatory factors were analysed with fluorescent immunochemistry and western blot, respectively. We tested brain vasomotor function with two-photon and laser speckle imaging in vivo, and measured glymphatic system function by two-photon imaging in vivo and fluorescence tracer imaging ex vivo, using awake and anesthetized mice. Besides, we monitored cortical spreading depression by laser speckle imaging system. AQP4 depolarization is analysed by fluorescent immunochemistry and western blot. RESULTS We confirmed that CUMS elicited depression-like and amnestic symptoms, accompanied by decreased monoamines neurotransmitter concentration in PFC and upregulated neuroinflammation markers. Moreover, CUMS mice showed reduced arterial pulsation and compliance in brain, and exhibited depolarized expression of AQP4, thus indicating glymphatic dysfunction both in awake and anesthetized states. PUFA supplementation rescued depression-like behaviours of CUMS mice, reduced neuroinflammation and cerebrovascular dysfunction, ultimately improved cognitive performance, all of which accompanied by restoring glymphatic system function. In contrast, Es treatment alleviated only the depression-like behavioural symptoms, while showing no effects on glymphatic function and depression-incident cognitive deficits. CONCLUSIONS The CUMS depression model entails suppression of the glymphatic system. PUFA supplementation rescued most behavioural signs of depression and the associated cognitive dysfunction by restoring the underlying glymphatic system disruption and protecting cerebral vascular function.
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Affiliation(s)
- Xinghua Liu
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Trauma Centre/Department of Emergency and Trauma Surgery, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jiahuan Hao
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Ensheng Yao
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jie Cao
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xiaolong Zheng
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Di Yao
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Chenyan Zhang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Jia Li
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Dengji Pan
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Xiang Luo
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China
| | - Minghuan Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
| | - Wei Wang
- Department of Neurology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China; Key Laboratory of Neurological Diseases of Chinese Ministry of Education, the School of Basic Medicine, Tongji Medical College, Huazhong University of Science and Technology, Wuhan 430030, China.
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427
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Benveniste H, Elkin R, Heerdt PM, Koundal S, Xue Y, Lee H, Wardlaw J, Tannenbaum A. The glymphatic system and its role in cerebral homeostasis. J Appl Physiol (1985) 2020; 129:1330-1340. [PMID: 33002383 DOI: 10.1152/japplphysiol.00852.2019] [Citation(s) in RCA: 16] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The brain's high bioenergetic state is paralleled by high metabolic waste production. Authentic lymphatic vasculature is lacking in brain parenchyma. Cerebrospinal fluid (CSF) flow has long been thought to facilitate central nervous system detoxification in place of lymphatics, but the exact processes involved in toxic waste clearance from the brain remain incompletely understood. Over the past 8 yr, novel data in animals and humans have begun to shed new light on these processes in the form of the "glymphatic system," a brain-wide perivascular transit passageway dedicated to CSF transport and interstitial fluid exchange that facilitates metabolic waste drainage from the brain. Here we will discuss glymphatic system anatomy and methods to visualize and quantify glymphatic system (GS) transport in the brain and also discuss physiological drivers of its function in normal brain and in neurodegeneration.
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Affiliation(s)
- Helene Benveniste
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
| | - Rena Elkin
- Departments of Computer Science and Applied Mathematics & Statistics, Stony Brook University, Stony Brook, New York
| | - Paul M Heerdt
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
| | - Sunil Koundal
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
| | - Yuechuan Xue
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
| | - Hedok Lee
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
| | - Joanna Wardlaw
- Brain Research Imaging Centre, Centre for Clinical Brain Sciences, Dementia Research Institute at the University of Edinburgh, Edinburgh, United Kingdom
| | - Allen Tannenbaum
- Departments of Computer Science and Applied Mathematics & Statistics, Stony Brook University, Stony Brook, New York
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428
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Giannetto M, Xia M, Stæger FF, Metcalfe T, Vinitsky HS, Dang JAML, Xavier ALR, Kress BT, Nedergaard M, Hablitz LM. Biological sex does not predict glymphatic influx in healthy young, middle aged or old mice. Sci Rep 2020; 10:16073. [PMID: 32999319 PMCID: PMC7528110 DOI: 10.1038/s41598-020-72621-3] [Citation(s) in RCA: 30] [Impact Index Per Article: 7.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2020] [Accepted: 08/10/2020] [Indexed: 11/09/2022] Open
Abstract
Sexual dimorphism is evident in brain structure, size, and function throughout multiple species. Here, we tested whether cerebrospinal fluid entry into the glymphatic system, a network of perivascular fluid transport that clears metabolic waste from the brain, was altered between male and female mice. We analyze glymphatic influx in 244 young reproductive age (2-4 months) C57BL/6 mice. We found no male/female differences in total influx under anesthesia, or across the anterior/posterior axis of the brain. Circadian-dependent changes in glymphatic influx under ketamine/xylazine anesthesia were not altered by sex. This was not true for diurnal rhythms under pentobarbital and avertin, but both still showed daily oscillations independent of biological sex. Finally, although glymphatic influx decreases with age there was no sex difference in total influx or subregion-dependent tracer distribution in 17 middle aged (9-10 months) and 36 old (22-24 months) mice. Overall, in healthy adult C57BL/6 mice we could not detect male/female differences in glymphatic influx. This finding contrasts the gender differences in common neurodegenerative diseases. We propose that additional sex-dependent co-morbidities, such as chronic stress, protein misfolding, traumatic brain injury or other pathological mechanisms may explain the increased risk for developing proteinopathies rather than pre-existing suppression of glymphatic influx.
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Affiliation(s)
- Michael Giannetto
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Maosheng Xia
- Laboratory of Brain Metabolic Diseases, Institute of Metabolic Disease Research and Drug Development, China Medical University, No. 77, Puhe Street, Shenbei District, Shenyang, 110177, People's Republic of China.,Department of Orthopaedics, The First Hospital of China Medical University, Shenyang, People's Republic of China
| | - Frederik Filip Stæger
- Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Tanner Metcalfe
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Hanna S Vinitsky
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Juliana A M L Dang
- Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Anna L R Xavier
- Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Benjamin T Kress
- Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA. .,Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark.
| | - Lauren M Hablitz
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
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429
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Christensen J, Yamakawa GR, Shultz SR, Mychasiuk R. Is the glymphatic system the missing link between sleep impairments and neurological disorders? Examining the implications and uncertainties. Prog Neurobiol 2020; 198:101917. [PMID: 32991958 DOI: 10.1016/j.pneurobio.2020.101917] [Citation(s) in RCA: 41] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 09/09/2020] [Accepted: 09/21/2020] [Indexed: 12/11/2022]
Abstract
Until recently, both the purpose of the biological need for sleep and the mechanism by which the central nervous system eliminated metabolic waste products were unknown. The glymphatic system is the recently discovered macroscopic waste clearance system for the CNS, which predominantly functions during sleep states. Important implications for the glymphatic system exist for a significant proportion of neurological disorders, including traumatic brain injury, epilepsy, stroke, migraine, and Alzheimer's disease. Within the limited amount of research pertaining to this novel system there exists controversy regarding several of the key structural and functional aspects of the glymphatic system. In this review we address evidence from both standpoints regarding the prominent debates surrounding the glymphatic system, including the functional differences in wakefulness vs. sleep, the role of glial aquaporin-4 water channels, and whether it reflects a convective flow or a passive diffusion process. The answers that underlie these questions will have crucial and distinct outcomes for the future of the glymphatic system and the disorders it has been implicated in. However, this review also summarizes the potential role of the glymphatic system in the development and progression of the aforementioned neurological disorders. Furthermore, the possible contribution of the orexinergic system to this relationship between the glymphatic system, sleep, and these neurological disorders is also explored. Overall, in order to develop and utilize therapeutic interventions centred around the glymphatic system we must first dedicate further investigation to elucidating these discrepancies and unanswered questions.
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Affiliation(s)
- Jennaya Christensen
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - Glenn R Yamakawa
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - Sandy R Shultz
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia
| | - Richelle Mychasiuk
- Department of Neuroscience, Central Clinical School, Monash University, Melbourne, Victoria, Australia.
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430
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Stringer MS, Lee H, Huuskonen MT, MacIntosh BJ, Brown R, Montagne A, Atwi S, Ramirez J, Jansen MA, Marshall I, Black SE, Zlokovic BV, Benveniste H, Wardlaw JM. A Review of Translational Magnetic Resonance Imaging in Human and Rodent Experimental Models of Small Vessel Disease. Transl Stroke Res 2020; 12:15-30. [PMID: 32936435 PMCID: PMC7803876 DOI: 10.1007/s12975-020-00843-8] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/01/2020] [Revised: 08/16/2020] [Accepted: 08/19/2020] [Indexed: 12/29/2022]
Abstract
Cerebral small vessel disease (SVD) is a major health burden, yet the pathophysiology remains poorly understood with no effective treatment. Since much of SVD develops silently and insidiously, non-invasive neuroimaging such as MRI is fundamental to detecting and understanding SVD in humans. Several relevant SVD rodent models are established for which MRI can monitor in vivo changes over time prior to histological examination. Here, we critically review the MRI methods pertaining to salient rodent models and evaluate synergies with human SVD MRI methods. We found few relevant publications, but argue there is considerable scope for greater use of MRI in rodent models, and opportunities for harmonisation of the rodent-human methods to increase the translational potential of models to understand SVD in humans. We summarise current MR techniques used in SVD research, provide recommendations and examples and highlight practicalities for use of MRI SVD imaging protocols in pre-selected, relevant rodent models.
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Affiliation(s)
- Michael S Stringer
- Brain Research Imaging Centre, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK.,UK Dementia Research Institute, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK
| | - Hedok Lee
- Department of Anesthesiology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Mikko T Huuskonen
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.,Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Bradley J MacIntosh
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada.,Hurvitz Brain Sciences Research Program, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Rosalind Brown
- Brain Research Imaging Centre, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK.,UK Dementia Research Institute, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK
| | - Axel Montagne
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.,Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Sarah Atwi
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada.,Department of Medical Biophysics, University of Toronto, Toronto, ON, Canada
| | - Joel Ramirez
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada.,Hurvitz Brain Sciences Research Program, Sunnybrook Research Institute, Toronto, ON, Canada
| | - Maurits A Jansen
- Edinburgh Preclinical Imaging, Centre for Cardiovascular Science, University of Edinburgh, Edinburgh, UK
| | - Ian Marshall
- Brain Research Imaging Centre, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK.,UK Dementia Research Institute, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK
| | - Sandra E Black
- Heart and Stroke Foundation Canadian Partnership for Stroke Recovery, Sunnybrook Research Institute, University of Toronto, Toronto, ON, Canada.,Hurvitz Brain Sciences Research Program, Sunnybrook Research Institute, Toronto, ON, Canada.,Department of Medicine (Neurology), University of Toronto, Toronto, ON, Canada
| | - Berislav V Zlokovic
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA.,Department of Physiology and Neuroscience, Keck School of Medicine, University of Southern California, Los Angeles, CA, USA
| | - Helene Benveniste
- Department of Anesthesiology, Yale School of Medicine, Yale University, New Haven, CT, USA
| | - Joanna M Wardlaw
- Brain Research Imaging Centre, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK. .,UK Dementia Research Institute, Edinburgh Medical School, University of Edinburgh, Edinburgh, UK.
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431
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Xue Y, Liu X, Koundal S, Constantinou S, Dai F, Santambrogio L, Lee H, Benveniste H. In vivo T1 mapping for quantifying glymphatic system transport and cervical lymph node drainage. Sci Rep 2020; 10:14592. [PMID: 32884041 PMCID: PMC7471332 DOI: 10.1038/s41598-020-71582-x] [Citation(s) in RCA: 25] [Impact Index Per Article: 6.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/29/2020] [Accepted: 07/24/2020] [Indexed: 12/13/2022] Open
Abstract
Dynamic contrast-enhanced magnetic resonance imaging (MRI) for tracking glymphatic system transport with paramagnetic contrast such as gadoteric acid (Gd-DOTA) administration into cerebrospinal fluid (CSF) requires pre-contrast data for proper quantification. Here we introduce an alternative approach for glymphatic system quantification in the mouse brain via T1 mapping which also captures drainage of Gd-DOTA to the cervical lymph nodes. The Gd-DOTA injection into CSF was performed on the bench after which the mice underwent T1 mapping using a 3D spoiled gradient echo sequence on a 9.4 T MRI. In Ketamine/Xylazine (KX) anesthetized mice, glymphatic transport and drainage of Gd-DOTA to submandibular and deep cervical lymph nodes was demonstrated as 25–50% T1 reductions in comparison to control mice receiving CSF saline. To further validate the T1 mapping approach we also verified increased glymphatic transport of Gd-DOTA transport in mice anesthetized with KX in comparison with ISO. The novel T1 mapping method allows for quantification of glymphatic transport as well as drainage to the deep and superficial cervical lymph nodes. The ability to measure glymphatic transport and cervical lymph node drainage in the same animal longitudinally is advantageous and time efficient and the coupling between the two systems can be studied and translated to human studies.
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Affiliation(s)
- Yuechuan Xue
- Department of Anesthesiology, Yale School of Medicine, 330 Cedar St, TMP 3, New Haven, CT, 06520, USA.,Department of Critical Care Medicine, Xiangya Hospital, Central South University, Changsha, 410008, Hunan, China
| | - Xiaodan Liu
- Department of Anesthesiology, Yale School of Medicine, 330 Cedar St, TMP 3, New Haven, CT, 06520, USA
| | - Sunil Koundal
- Department of Anesthesiology, Yale School of Medicine, 330 Cedar St, TMP 3, New Haven, CT, 06520, USA
| | - Stefan Constantinou
- Department of Anesthesiology, Yale School of Medicine, 330 Cedar St, TMP 3, New Haven, CT, 06520, USA
| | - Feng Dai
- Yale Center for Analytical Sciences, Yale School of Public Health, New Haven, CT, USA
| | - Laura Santambrogio
- Englander Institute of Precision Medicine, Department of Radiation Oncology, Physiology and Biophysics, Weill Cornell Medicine, New York, NY, 10065, USA
| | - Hedok Lee
- Department of Anesthesiology, Yale School of Medicine, 330 Cedar St, TMP 3, New Haven, CT, 06520, USA
| | - Helene Benveniste
- Department of Anesthesiology, Yale School of Medicine, 330 Cedar St, TMP 3, New Haven, CT, 06520, USA.
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432
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Hablitz LM, Plá V, Giannetto M, Vinitsky HS, Stæger FF, Metcalfe T, Nguyen R, Benrais A, Nedergaard M. Circadian control of brain glymphatic and lymphatic fluid flow. Nat Commun 2020; 11:4411. [PMID: 32879313 PMCID: PMC7468152 DOI: 10.1038/s41467-020-18115-2] [Citation(s) in RCA: 300] [Impact Index Per Article: 75.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/17/2019] [Accepted: 07/24/2020] [Indexed: 12/20/2022] Open
Abstract
The glymphatic system is a network of perivascular spaces that promotes movement of cerebrospinal fluid (CSF) into the brain and clearance of metabolic waste. This fluid transport system is supported by the water channel aquaporin-4 (AQP4) localized to vascular endfeet of astrocytes. The glymphatic system is more effective during sleep, but whether sleep timing promotes glymphatic function remains unknown. We here show glymphatic influx and clearance exhibit endogenous, circadian rhythms peaking during the mid-rest phase of mice. Drainage of CSF from the cisterna magna to the lymph nodes exhibits daily variation opposite to glymphatic influx, suggesting distribution of CSF throughout the animal depends on time-of-day. The perivascular polarization of AQP4 is highest during the rest phase and loss of AQP4 eliminates the day-night difference in both glymphatic influx and drainage to the lymph nodes. We conclude that CSF distribution is under circadian control and that AQP4 supports this rhythm.
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Affiliation(s)
- Lauren M Hablitz
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA.
| | - Virginia Plá
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Michael Giannetto
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Hanna S Vinitsky
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Frederik Filip Stæger
- Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Tanner Metcalfe
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Rebecca Nguyen
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Abdellatif Benrais
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA.
- Center for Basic and Translational Neuroscience, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark.
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433
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Ng Kee Kwong KC, Mehta AR, Nedergaard M, Chandran S. Defining novel functions for cerebrospinal fluid in ALS pathophysiology. Acta Neuropathol Commun 2020; 8:140. [PMID: 32819425 PMCID: PMC7439665 DOI: 10.1186/s40478-020-01018-0] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/21/2020] [Accepted: 08/10/2020] [Indexed: 12/11/2022] Open
Abstract
Despite the considerable progress made towards understanding ALS pathophysiology, several key features of ALS remain unexplained, from its aetiology to its epidemiological aspects. The glymphatic system, which has recently been recognised as a major clearance pathway for the brain, has received considerable attention in several neurological conditions, particularly Alzheimer's disease. Its significance in ALS has, however, been little addressed. This perspective article therefore aims to assess the possibility of CSF contribution in ALS by considering various lines of evidence, including the abnormal composition of ALS-CSF, its toxicity and the evidence for impaired CSF dynamics in ALS patients. We also describe a potential role for CSF circulation in determining disease spread as well as the importance of CSF dynamics in ALS neurotherapeutics. We propose that a CSF model could potentially offer additional avenues to explore currently unexplained features of ALS, ultimately leading to new treatment options for people with ALS.
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Affiliation(s)
- Koy Chong Ng Kee Kwong
- UK Dementia Research Institute at University of Edinburgh, Edinburgh, UK
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh bioQuarter, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, UK
| | - Arpan R Mehta
- UK Dementia Research Institute at University of Edinburgh, Edinburgh, UK
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh bioQuarter, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, UK
- Anne Rowling Regenerative Neurology Clinic, University of Edinburgh, Edinburgh, UK
- Nuffield Department of Clinical Neurosciences, University of Oxford, Oxford, UK
| | - 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, NY, USA
| | - Siddharthan Chandran
- UK Dementia Research Institute at University of Edinburgh, Edinburgh, UK.
- Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh bioQuarter, Chancellor's Building, 49 Little France Crescent, Edinburgh, EH16 4SB, UK.
- Euan MacDonald Centre for MND Research, University of Edinburgh, Edinburgh, UK.
- Anne Rowling Regenerative Neurology Clinic, University of Edinburgh, Edinburgh, UK.
- Centre for Brain Development and Repair, inStem, Bangalore, India.
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434
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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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435
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Berggreen E, Wiig H, Virtej A. Fluid transport from the dental pulp revisited. Eur J Oral Sci 2020; 128:365-368. [PMID: 32794278 DOI: 10.1111/eos.12733] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 07/20/2020] [Indexed: 11/30/2022]
Abstract
In the dental pulp surrounded by rigid dentinal walls, an increase in fluid volume will be followed by a rapid increase in interstitial fluid pressure. To maintain pressure homeostasis, a fluid drainage system is required. The dental pulp and apical periodontal ligament lack lymphatic vessels, and the questions are how the transport can take place inside the pulp and where the lymphatic vessels draining fluid from the apical periodontal ligament are located. The drainage of fluid within the pulp must be governed by a tissue pressure gradient (driving pressure) and the fluid is likely transported in loose connective tissue (gaps) surrounding vessels and nerve fibers. We suggest that aging of the pulp tissue characterized by fibrosis will reduce the draining capacity and make it more vulnerable to circulatory failure. When the fluid leaves the pulp, it will follow the nerve bundles and vessels through the periapical ligament into bone channels, where lymphatic vessels are found. In the mandibular canal, lymphatic vessels are localized and the fluid washout rate from the canal is slow, but chewing may speed it up by increasing the fluid pressure. In acute apical periodontitis, inflammatory mediators and bacterial components can be spread to regional lymph nodes via lymphatic vessels inside the jaw bone.
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Affiliation(s)
- Ellen Berggreen
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Helge Wiig
- Department of Biomedicine, University of Bergen, Bergen, Norway
| | - Anca Virtej
- Department of Biomedicine, University of Bergen, Bergen, Norway.,Department of Oral and Maxillofacial Surgery, Haukeland University Hospital, Bergen, Norway
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436
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Rivera-Rivera LA, Cody KA, Rutkowski D, Cary P, Eisenmenger L, Rowley HA, Carlsson CM, Johnson SC, Johnson KM. Intracranial vascular flow oscillations in Alzheimer's disease from 4D flow MRI. Neuroimage Clin 2020; 28:102379. [PMID: 32871386 PMCID: PMC7476069 DOI: 10.1016/j.nicl.2020.102379] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2020] [Revised: 07/10/2020] [Accepted: 08/07/2020] [Indexed: 11/26/2022]
Abstract
Recent modeling and experimental evidence suggests clearance of soluble metabolites from the brain can be driven by low frequency flow oscillations (LFOs) through the intramural periarterial drainage (IPAD) pathway. This study investigates the use of 4D flow MRI to derive LFOs from arterial and venous measures of blood flow. 3D radial 4D flow MRI data were acquired on a 3.0 T scanner and reconstructed using a low-rank constraint to produce time resolved measurements of blood flow. Physical phantom experiments were performed to validate the time resolved 4D flow against a standard 2D phase contrast (PC) approach. To evaluate the ability of 4D flow to distinguish physiologic flow changes from noise, healthy volunteers were scanned during a breath-hold (BH) maneuver and compared against 2D PC measures. Finally, flow measures were performed in intracranial arteries and veins of 112 participants including subjects diagnosed with Alzheimer's disease (AD) clinical syndrome (n = 23), and healthy controls (n = 89) on whom apolipoprotein ɛ4 positivity (APOE4+) and parental history of AD dementia (FH+) was known. To assess LFOs, flow range, standard deviation, demeaned temporal flow changes, and power spectral density were quantified from the time series. Group differences were assessed using ANOVA followed by Tukey-Kramer method for pairwise comparison for adjusted means (P < 0.05). Significantly lower LFOs as measured from flow variation range and standard deviations were observed in the arteries of AD subjects when compared to age-matched controls (P = 0.005, P = 0.011). Results suggest altered vascular function in AD subjects. 4D flow based spontaneous LFO measures might hold potential for longitudinal studies aimed at predicting cognitive trajectories in AD and study disease mechanisms.
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Affiliation(s)
- Leonardo A Rivera-Rivera
- Department of Medical Physics, University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA
| | - Karly A Cody
- Alzheimer's Disease Research Center, University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA
| | - David Rutkowski
- Department of Radiology, University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA
| | - Paul Cary
- Alzheimer's Disease Research Center, University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA
| | - Laura Eisenmenger
- Department of Radiology, University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA
| | - Howard A Rowley
- Alzheimer's Disease Research Center, University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA; Department of Radiology, University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA
| | - Cynthia M Carlsson
- Alzheimer's Disease Research Center, University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA; Geriatric Research Education and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, WI, USA
| | - Sterling C Johnson
- Alzheimer's Disease Research Center, University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA; Geriatric Research Education and Clinical Center, William S. Middleton Memorial Veterans Hospital, Madison, WI, USA
| | - Kevin M Johnson
- Department of Medical Physics, University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA; Department of Radiology, University of Wisconsin, School of Medicine and Public Health, Madison, WI, USA.
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437
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Fame RM, Lehtinen MK. Emergence and Developmental Roles of the Cerebrospinal Fluid System. Dev Cell 2020; 52:261-275. [PMID: 32049038 DOI: 10.1016/j.devcel.2020.01.027] [Citation(s) in RCA: 107] [Impact Index Per Article: 26.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/15/2019] [Revised: 01/14/2020] [Accepted: 01/24/2020] [Indexed: 12/21/2022]
Abstract
We summarize recent work illuminating how cerebrospinal fluid (CSF) regulates brain function. More than a protective fluid cushion and sink for waste, the CSF is an integral CNS component with dynamic and diverse roles emerging in parallel with the developing CNS. This review examines the current understanding about early CSF and its maturation and roles during CNS development and discusses open questions in the field. We focus on developmental changes in the ventricular system and CSF sources (including neural progenitors and choroid plexus). We also discuss concepts related to the development of fluid dynamics including flow, perivascular transport, drainage, and barriers.
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Affiliation(s)
- Ryann M Fame
- Department of Pathology, Boston Children's Hospital, Boston, MA 02115, USA
| | - Maria K Lehtinen
- Department of Pathology, Boston Children's Hospital, Boston, MA 02115, USA.
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438
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Goodman JR, Iliff JJ. Vasomotor influences on glymphatic-lymphatic coupling and solute trafficking in the central nervous system. J Cereb Blood Flow Metab 2020; 40:1724-1734. [PMID: 31506012 PMCID: PMC7370362 DOI: 10.1177/0271678x19874134] [Citation(s) in RCA: 27] [Impact Index Per Article: 6.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/18/2022]
Abstract
Despite the recent description of meningeal lymphatic vessels draining solutes from the brain interstitium and cerebrospinal fluid (CSF), the physiological factors governing cranial lymphatic efflux remain largely unexplored. In agreement with recent findings, cervical lymphatic drainage of 70 kD and 2000 kD fluorescent tracers injected into the adult mouse cortex was significantly impaired in the anesthetized compared to waking animals (tracer distribution across 2.1 ± 4.5% and 23.7 ± 15.8% of deep cervical lymph nodes, respectively); however, free-breathing anesthetized mice were markedly hypercapnic and acidemic (paCO2 = 64 ± 8 mmHg; pH = 7.22 ± 0.05). Mechanical ventilation normalized arterial blood gases in anesthetized animals, and rescued lymphatic efflux of interstitial solutes in anesthetized mice. Experimental hypercapnia blocked cervical lymphatic efflux of intraparenchymal tracers. When tracers were injected into the subarachnoid CSF compartment, glymphatic influx into brain tissue was virtually abolished by hypercapnia, while lymphatic drainage was not appreciably altered. These findings demonstrate that cervical lymphatic drainage of interstitial solutes is, in part, regulated by upstream changes in glymphatic CSF-interstitial fluid exchange. Further, they suggest that maintaining physiological blood gas values in studies of glymphatic exchange and meningeal lymphatic drainage may be critical to defining the physiological regulation of these processes.
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Affiliation(s)
- James R Goodman
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA.,Department of Physiology and Pharmacology, Oregon Health & Science University, Portland, OR, USA
| | - Jeffrey J Iliff
- Department of Anesthesiology and Perioperative Medicine, Oregon Health & Science University, Portland, OR, USA.,Knight Cardiovascular Institute, Oregon Health & Science University, Portland, OR, USA
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439
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Mechanisms behind altered pulsatile intracranial pressure in idiopathic normal pressure hydrocephalus: role of vascular pulsatility and systemic hemodynamic variables. Acta Neurochir (Wien) 2020; 162:1803-1813. [PMID: 32533412 PMCID: PMC7360648 DOI: 10.1007/s00701-020-04423-5] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2020] [Accepted: 05/19/2020] [Indexed: 12/15/2022]
Abstract
BACKGROUND The dementia subtype idiopathic normal pressure hydrocephalus (iNPH) has unknown etiology, but one characteristic is elevated intracranial pressure (ICP) wave amplitudes in those individuals who respond with clinical improvement following cerebrospinal fluid (CSF) diversion. To explore the mechanisms behind altered ICP wave amplitudes, we correlated central aortic blood pressure (BP) and ICP waveform amplitudes (intracranial aortic amplitude correlation) and examined how this correlation relates to ICP wave amplitude levels and systemic hemodynamic parameters. METHODS The study included 29 patients with probable iNPH who underwent continuous multi-hour measurement of ICP, radial artery BP, and systemic hemodynamic parameters. The radial artery BP waveforms were used to estimate central aortic BP waveforms, and the intracranial aortic amplitude correlation was determined over consecutive 4-min periods. RESULTS The average intracranial aortic amplitude correlation was 0.28 ± 0.16 at the group level. In the majority of iNPH patients, the intracranial aortic amplitude correlation was low, while in about 1/5 patients, the correlation was rather high (average Pearson correlation coefficient > 0.4). The degree of correlation was hardly influenced by systemic hemodynamic parameters. CONCLUSIONS In about 1/5 iNPH patients of this study, the intracranial aortic amplitude correlation (IAACAORTIC) was rather high (average Pearson correlation coefficient > 0.4), suggesting that cerebrovascular factors to some extent may affect the ICP wave amplitudes in a subset of patients. However, in 14/19 (74%) iNPH patients with elevated ICP wave amplitudes, the intracranial aortic amplitude correlation was low, indicating that the ICP pulse amplitude in most iNPH patients is independent of central vascular excitation, ergo it is modulated by local cerebrospinal physiology. In support of this assumption, the intracranial aortic amplitude correlation was not related to most systemic hemodynamic variables. An exception was found for a subgroup of the patients with high systemic vascular resistance, where there was a correlation.
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440
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Zhang Y, Song J, He XZ, Xiong J, Xue R, Ge JH, Lu SY, Hu D, Zhang GX, Xu GY, Wang LH. Quantitative Determination of Glymphatic Flow Using Spectrophotofluorometry. Neurosci Bull 2020; 36:1524-1537. [PMID: 32710307 DOI: 10.1007/s12264-020-00548-w] [Citation(s) in RCA: 5] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 05/06/2020] [Indexed: 12/16/2022] Open
Abstract
Following intrathecal injection of fluorescent tracers, ex vivo imaging of brain vibratome slices has been widely used to study the glymphatic system in the rodent brain. Tracer penetration into the brain is usually quantified by image-processing, even though this approach requires much time and manual operation. Here, we illustrate a simple protocol for the quantitative determination of glymphatic activity using spectrophotofluorometry. At specific time-points following intracisternal or intrastriatal injection of fluorescent tracers, certain brain regions and the spinal cord were harvested and tracers were extracted from the tissue. The intensity of tracers was analyzed spectrophotometrically and their concentrations were quantified from standard curves. Using this approach, the regional and dynamic delivery of subarachnoid CSF tracers into the brain parenchyma was assessed, and the clearance of tracers from the brain was also determined. Furthermore, the impairment of glymphatic influx in the brains of old mice was confirmed using our approach. Our method is more accurate and efficient than the imaging approach in terms of the quantitative determination of glymphatic activity, and this will be useful in preclinical studies.
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Affiliation(s)
- Yu Zhang
- Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou, 215123, China
| | - Jian Song
- Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou, 215123, China
| | - Xu-Zhong He
- Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou, 215123, China
| | - Jian Xiong
- Institute of Medical Biotechnology, Suzhou Vocational Health College, Suzhou, 215009, China
| | - Rong Xue
- Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou, 215123, China
| | - Jia-Hao Ge
- Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou, 215123, China
| | - Shi-Yu Lu
- Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou, 215123, China
| | - Die Hu
- Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou, 215123, China
| | - Guo-Xing Zhang
- Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou, 215123, China
| | - Guang-Yin Xu
- Institute of Neuroscience, Soochow University, Suzhou, 215123, China.
| | - Lin-Hui Wang
- Department of Physiology and Neurobiology, Medical College of Soochow University, Suzhou, 215123, China.
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441
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Braun M, Iliff JJ. The impact of neurovascular, blood-brain barrier, and glymphatic dysfunction in neurodegenerative and metabolic diseases. INTERNATIONAL REVIEW OF NEUROBIOLOGY 2020; 154:413-436. [PMID: 32739013 DOI: 10.1016/bs.irn.2020.02.006] [Citation(s) in RCA: 33] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 02/07/2023]
Abstract
The cerebral vasculature serves as the crossroads of the CNS, supporting exchange of nutrients, metabolic wastes, solutes and cells between the compartments of the brain, including the blood, brain interstitium, and cerebrospinal fluid (CSF). The blood-brain barrier (BBB) regulates the entry and efflux of molecules into brain tissue. The cells of the neurovascular unit regulate cerebral blood flow, matching local metabolic demand to blood supply. The blood-CSF barrier at the choroid plexus secretes CSF, which supports the brain and provides a sink for interstitial solutes not cleared across the BBB. Recent studies have characterized the glymphatic system, a brain-wide network of perivascular spaces that supports CSF and interstitial fluid exchange and the clearance of interstitial solutes to the CSF. The critical role that these structures play in maintaining brain homeostasis is illustrated by the established and emerging roles that their dysfunctions play in the development of neurodegenerative diseases, such as Alzheimer's disease (AD). Loss of BBB and blood-CSF barrier function is reported both in rodent models of AD, and in human AD subjects. Cerebrovascular dysfunction and ischemic injury are well established contributors to both vascular dementia and to a large proportion of cases of sporadic AD. In animal models, the slowed glymphatic clearance of interstitial proteins, such as amyloid β or tau, are proposed to contribute to the development of neurodegenerative diseases, including AD. In total, these findings suggest that cellular and molecular changes occurring within and around the cerebral vasculature are among the key drivers of neurodegenerative disease pathogenesis.
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Affiliation(s)
- Molly Braun
- Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA, United States; VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), VA Puget Sound Health Care System, Seattle, WA, United States
| | - Jeffrey J Iliff
- Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, WA, United States; VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), VA Puget Sound Health Care System, Seattle, WA, United States; Department of Neurology, University of Washington School of Medicine, Seattle, WA, United States.
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442
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Clinically-derived vagus nerve stimulation enhances cerebrospinal fluid penetrance. Brain Stimul 2020; 13:1024-1030. [DOI: 10.1016/j.brs.2020.03.012] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/23/2019] [Revised: 02/07/2020] [Accepted: 03/18/2020] [Indexed: 02/07/2023] Open
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443
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Gallina P, Scollato A, Nicoletti C, Lolli F. Letter to the Editor. Cerebrospinal fluid circulation failure in the pathogenesis of post-craniectomy glymphatic flow impairment. J Neurosurg 2020; 133:267-270. [PMID: 31783370 DOI: 10.3171/2019.6.jns191758] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/06/2022]
Affiliation(s)
- Pasquale Gallina
- 1Florence School of Neurosurgery, University of Florence, Italy Careggi University Hospital, Florence, Italy
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444
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Naessens DMP, Coolen BF, de Vos J, VanBavel E, Strijkers GJ, Bakker ENTP. Altered brain fluid management in a rat model of arterial hypertension. Fluids Barriers CNS 2020; 17:41. [PMID: 32590994 PMCID: PMC7318739 DOI: 10.1186/s12987-020-00203-6] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/14/2020] [Accepted: 06/18/2020] [Indexed: 12/22/2022] Open
Abstract
Background Proper neuronal function is directly dependent on the composition, turnover, and amount of interstitial fluid that bathes the cells. Most of the interstitial fluid is likely to be derived from ion and water transport across the brain capillary endothelium, a process that may be altered in hypertension due to vascular pathologies as endothelial dysfunction and arterial remodelling. In the current study, we investigated the effects of hypertension on the brain for differences in the water homeostasis. Methods Magnetic resonance imaging (MRI) was performed on a 7T small animal MRI system on male spontaneously hypertensive rats (SHR) and normotensive Wistar Kyoto rats (WKY) of 10 months of age. The MRI protocol consisted of T2-weighted scans followed by quantitative apparent diffusion coefficient (ADC) mapping to measure volumes of different anatomical structures and water diffusion respectively. After MRI, we assessed the spatial distribution of aquaporin 4 expression around blood vessels. Results MRI analysis revealed a significant reduction in overall brain volume and remarkably higher cerebroventricular volume in SHR compared to WKY. Whole brain ADC, as well as ADC values of a number of specific anatomical structures, were significantly lower in hypertensive animals. Additionally, SHR exhibited higher brain parenchymal water content. Immunohistochemical analysis showed a profound expression of aquaporin 4 around blood vessels in both groups, with a significantly larger area of influence around arterioles. Evaluation of specific brain regions revealed a decrease in aquaporin 4 expression around capillaries in the corpus callosum of SHR. Conclusion These results indicate a shift in the brain water homeostasis of adult hypertensive rats.
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Affiliation(s)
- Daphne M P Naessens
- Department of Biomedical Engineering and Physics, Amsterdam Cardiovascular Sciences, Amsterdam Neuroscience, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Bram F Coolen
- Department of Biomedical Engineering and Physics, Amsterdam Cardiovascular Sciences, Amsterdam Neuroscience, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Judith de Vos
- Department of Biomedical Engineering and Physics, Amsterdam Cardiovascular Sciences, Amsterdam Neuroscience, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Ed VanBavel
- Department of Biomedical Engineering and Physics, Amsterdam Cardiovascular Sciences, Amsterdam Neuroscience, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Gustav J Strijkers
- Department of Biomedical Engineering and Physics, Amsterdam Cardiovascular Sciences, Amsterdam Neuroscience, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands
| | - Erik N T P Bakker
- Department of Biomedical Engineering and Physics, Amsterdam Cardiovascular Sciences, Amsterdam Neuroscience, University of Amsterdam, Meibergdreef 9, 1105 AZ, Amsterdam, The Netherlands.
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445
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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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446
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Kananen J, Helakari H, Korhonen V, Huotari N, Järvelä M, Raitamaa L, Raatikainen V, Rajna Z, Tuovinen T, Nedergaard M, Jacobs J, LeVan P, Ansakorpi H, Kiviniemi V. Respiratory-related brain pulsations are increased in epilepsy-a two-centre functional MRI study. Brain Commun 2020; 2:fcaa076. [PMID: 32954328 PMCID: PMC7472909 DOI: 10.1093/braincomms/fcaa076] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/13/2020] [Revised: 04/29/2020] [Accepted: 05/05/2020] [Indexed: 01/03/2023] Open
Abstract
Resting-state functional MRI has shown potential for detecting changes in cerebral blood oxygen level-dependent signal in patients with epilepsy, even in the absence of epileptiform activity. Furthermore, it has been suggested that coefficient of variation mapping of fast functional MRI signal may provide a powerful tool for the identification of intrinsic brain pulsations in neurological diseases such as dementia, stroke and epilepsy. In this study, we used fast functional MRI sequence (magnetic resonance encephalography) to acquire ten whole-brain images per second. We used the functional MRI data to compare physiological brain pulsations between healthy controls (n = 102) and patients with epilepsy (n = 33) and furthermore to drug-naive seizure patients (n = 9). Analyses were performed by calculating coefficient of variation and spectral power in full band and filtered sub-bands. Brain pulsations in the respiratory-related frequency sub-band (0.11-0.51 Hz) were significantly (P < 0.05) increased in patients with epilepsy, with an increase in both signal variance and power. At the individual level, over 80% of medicated and drug-naive seizure patients exhibited areas of abnormal brain signal power that correlated well with the known clinical diagnosis, while none of the controls showed signs of abnormality with the same threshold. The differences were most apparent in the basal brain structures, respiratory centres of brain stem, midbrain and temporal lobes. Notably, full-band, very low frequency (0.01-0.1 Hz) and cardiovascular (0.8-1.76 Hz) brain pulses showed no differences between groups. This study extends and confirms our previous results of abnormal fast functional MRI signal variance in epilepsy patients. Only respiratory-related brain pulsations were clearly increased with no changes in either physiological cardiorespiratory rates or head motion between the subjects. The regional alterations in brain pulsations suggest that mechanisms driving the cerebrospinal fluid homeostasis may be altered in epilepsy. Magnetic resonance encephalography has both increased sensitivity and high specificity for detecting the increased brain pulsations, particularly in times when other tools for locating epileptogenic areas remain inconclusive.
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Affiliation(s)
- Janne Kananen
- Oulu Functional NeuroImaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu 90029, Finland
- Medical Imaging, Physics and Technology (MIPT), Faculty of Medicine, University of Oulu, Oulu 90220, Finland
- Medical Research Center (MRC), Oulu 90220, Finland
| | - Heta Helakari
- Oulu Functional NeuroImaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu 90029, Finland
- Medical Imaging, Physics and Technology (MIPT), Faculty of Medicine, University of Oulu, Oulu 90220, Finland
- Medical Research Center (MRC), Oulu 90220, Finland
| | - Vesa Korhonen
- Oulu Functional NeuroImaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu 90029, Finland
- Medical Imaging, Physics and Technology (MIPT), Faculty of Medicine, University of Oulu, Oulu 90220, Finland
- Medical Research Center (MRC), Oulu 90220, Finland
| | - Niko Huotari
- Oulu Functional NeuroImaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu 90029, Finland
- Medical Imaging, Physics and Technology (MIPT), Faculty of Medicine, University of Oulu, Oulu 90220, Finland
- Medical Research Center (MRC), Oulu 90220, Finland
| | - Matti Järvelä
- Oulu Functional NeuroImaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu 90029, Finland
- Medical Imaging, Physics and Technology (MIPT), Faculty of Medicine, University of Oulu, Oulu 90220, Finland
- Medical Research Center (MRC), Oulu 90220, Finland
| | - Lauri Raitamaa
- Oulu Functional NeuroImaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu 90029, Finland
- Medical Imaging, Physics and Technology (MIPT), Faculty of Medicine, University of Oulu, Oulu 90220, Finland
- Medical Research Center (MRC), Oulu 90220, Finland
| | - Ville Raatikainen
- Oulu Functional NeuroImaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu 90029, Finland
- Medical Imaging, Physics and Technology (MIPT), Faculty of Medicine, University of Oulu, Oulu 90220, Finland
- Medical Research Center (MRC), Oulu 90220, Finland
| | - Zalan Rajna
- Oulu Functional NeuroImaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu 90029, Finland
- Center for Machine Vision and Signal Analysis (CMVS), University of Oulu, Oulu 90014, Finland
| | - Timo Tuovinen
- Oulu Functional NeuroImaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu 90029, Finland
- Medical Imaging, Physics and Technology (MIPT), Faculty of Medicine, University of Oulu, Oulu 90220, Finland
- Medical Research Center (MRC), Oulu 90220, Finland
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY 14642, USA
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen 2200, Denmark
| | - Julia Jacobs
- Department of Pediatric Neurology and Muscular Disease, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg 79110, Germany
- Department of Paediatrics, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Neuroscience, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
- Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Pierre LeVan
- Department of Paediatrics, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Neuroscience, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
- Hotchkiss Brain Institute and Alberta Children’s Hospital Research Institute, University of Calgary, Calgary, AB T2N 4N1, Canada
- Department of Radiology, Medical Physics, University Medical Center Freiburg, Faculty of Medicine, University of Freiburg, Freiburg 79110, Germany
- Department of Radiology, Cumming School of Medicine, University of Calgary, Calgary, AB T2N 4N1, Canada
| | - Hanna Ansakorpi
- Medical Research Center (MRC), Oulu 90220, Finland
- Research Unit of Neuroscience, Neurology, University of Oulu, Oulu 90220, Finland
- Department of Neurology, Oulu University Hospital, Oulu 90029, Finland
| | - Vesa Kiviniemi
- Oulu Functional NeuroImaging (OFNI), Department of Diagnostic Radiology, Oulu University Hospital, Oulu 90029, Finland
- Medical Imaging, Physics and Technology (MIPT), Faculty of Medicine, University of Oulu, Oulu 90220, Finland
- Medical Research Center (MRC), Oulu 90220, Finland
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447
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Valnes LM, Mitusch SK, Ringstad G, Eide PK, Funke SW, Mardal KA. Apparent diffusion coefficient estimates based on 24 hours tracer movement support glymphatic transport in human cerebral cortex. Sci Rep 2020; 10:9176. [PMID: 32514105 PMCID: PMC7280526 DOI: 10.1038/s41598-020-66042-5] [Citation(s) in RCA: 45] [Impact Index Per Article: 11.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/05/2019] [Accepted: 05/11/2020] [Indexed: 11/15/2022] Open
Abstract
The recently proposed glymphatic system suggests that bulk flow is important for clearing waste from the brain, and as such may underlie the development of e.g. Alzheimer’s disease. The glymphatic hypothesis is still controversial and several biomechanical modeling studies at the micro-level have questioned the system and its assumptions. In contrast, at the macro-level, there are many experimental findings in support of bulk flow. Here, we will investigate to what extent the CSF tracer distributions seen in novel magnetic resonance imaging (MRI) investigations over hours and days are suggestive of bulk flow as an additional component to diffusion. In order to include the complex geometry of the brain, the heterogeneous CSF flow around the brain, and the transport over the time-scale of days, we employed the methods of partial differential constrained optimization to identify the apparent diffusion coefficient (ADC) that would correspond best to the MRI findings. We found that the computed ADC in the cortical grey matter was 5–26% larger than the ADC estimated with DTI, which suggests that diffusion may not be the only mechanism governing transport.
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Affiliation(s)
| | - Sebastian K Mitusch
- Center for Biomedical Computing, Simula Research Laboratory, Lysaker, Norway
| | - Geir Ringstad
- Department of Radiology, Oslo University Hospital - Rikshospitalet, Oslo, Norway
| | - Per Kristian Eide
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.,Department of Neurosurgery, Oslo University Hospital - Rikshospitalet, Oslo, Norway
| | - Simon W Funke
- Center for Biomedical Computing, Simula Research Laboratory, Lysaker, Norway
| | - Kent-Andre Mardal
- Department of Mathematics, University of Oslo, Oslo, Norway. .,Center for Biomedical Computing, Simula Research Laboratory, Lysaker, Norway.
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448
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Williamson NH, Komlosh ME, Benjamini D, Basser PJ. Limits to flow detection in phase contrast MRI. JOURNAL OF MAGNETIC RESONANCE OPEN 2020; 2-3:100004. [PMID: 33345200 PMCID: PMC7745993 DOI: 10.1016/j.jmro.2020.100004] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/21/2023]
Abstract
Pulsed gradient spin echo (PGSE) complex signal behavior becomes dominated by attenuation rather than oscillation when displacements due to flow are similar or less than diffusive displacements. In this "slow-flow" regime, the optimal displacement encoding parameter q for phase contrast velocimetry depends on the diffusive length scale q s l o w = 1 / l D = 1 / 2 D Δ rather than the velocity encoding parameter v enc = π/(qΔ). The minimum detectable mean velocity using the difference between the phase at +q slow and -q slow is 〈 v m i n 〉 = 1 / SNR D / Δ . These theories are then validated and applied to MRI by performing PGSE echo planar imaging experiments on water flowing through a column with a bulk region and a beadpack region at controlled flow rates. Velocities as slow as 6 μm/s are detected with velocimetry. Theories, MRI experimental protocols, and validation on a controlled phantom help to bridge the gap between porous media NMR and pre-clinical phase contrast and diffusion MRI.
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Affiliation(s)
- Nathan H. Williamson
- National Institute of General Medical Sciences, National Institutes of Health, Bethesda, MD, USA
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
- Corresponding author: Nathan H. Williamson,
| | - Michal E. Komlosh
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
- The Center for Neuroscience and Regenerative Medicine, Uniformed Service University of the Health Sciences, Bethesda, MD, USA
| | - Dan Benjamini
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
- The Center for Neuroscience and Regenerative Medicine, Uniformed Service University of the Health Sciences, Bethesda, MD, USA
| | - Peter J. Basser
- Eunice Kennedy Shriver National Institute of Child Health and Human Development, National Institutes of Health, Bethesda, MD, USA
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449
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Hauglund NL, Pavan C, Nedergaard M. Cleaning the sleeping brain – the potential restorative function of the glymphatic system. CURRENT OPINION IN PHYSIOLOGY 2020. [DOI: 10.1016/j.cophys.2019.10.020] [Citation(s) in RCA: 18] [Impact Index Per Article: 4.5] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/13/2022]
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450
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Jurisch-Yaksi N, Yaksi E, Kizil C. Radial glia in the zebrafish brain: Functional, structural, and physiological comparison with the mammalian glia. Glia 2020; 68:2451-2470. [PMID: 32476207 DOI: 10.1002/glia.23849] [Citation(s) in RCA: 80] [Impact Index Per Article: 20.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/01/2020] [Revised: 05/07/2020] [Accepted: 05/13/2020] [Indexed: 02/01/2023]
Abstract
The neuroscience community has witnessed a tremendous expansion of glia research. Glial cells are now on center stage with leading roles in the development, maturation, and physiology of brain circuits. Over the course of evolution, glia have highly diversified and include the radial glia, astroglia or astrocytes, microglia, oligodendrocytes, and ependymal cells, each having dedicated functions in the brain. The zebrafish, a small teleost fish, is no exception to this and recent evidences point to evolutionarily conserved roles for glia in the development and physiology of its nervous system. Due to its small size, transparency, and genetic amenability, the zebrafish has become an increasingly prominent animal model for brain research. It has enabled the study of neural circuits from individual cells to entire brains, with a precision unmatched in other vertebrate models. Moreover, its high neurogenic and regenerative potential has attracted a lot of attention from the research community focusing on neural stem cells and neurodegenerative diseases. Hence, studies using zebrafish have the potential to provide fundamental insights about brain development and function, and also elucidate neural and molecular mechanisms of neurological diseases. We will discuss here recent discoveries on the diverse roles of radial glia and astroglia in neurogenesis, in modulating neuronal activity and in regulating brain homeostasis at the brain barriers. By comparing insights made in various animal models, particularly mammals and zebrafish, our goal is to highlight the similarities and differences in glia biology among species, which could set new paradigms relevant to humans.
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Affiliation(s)
- Nathalie Jurisch-Yaksi
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Clinical and Molecular Medicine, Norwegian University of Science and Technology, Trondheim, Norway.,Department of Neurology and Clinical Neurophysiology, St Olav University Hospital, Trondheim, Norway
| | - Emre Yaksi
- Kavli Institute for Systems Neuroscience and Centre for Neural Computation, Norwegian University of Science and Technology, Trondheim, Norway
| | - Caghan Kizil
- German Center for Neurodegenerative Diseases (DZNE), Helmholtz Association, Dresden, Germany.,Center for Molecular and Cellular Bioengineering (CMCB), TU Dresden, Dresden, Germany
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