1
|
van Osch MJP, Wåhlin A, Scheyhing P, Mossige I, Hirschler L, Eklund A, Mogensen K, Gomolka R, Radbruch A, Qvarlander S, Decker A, Nedergaard M, Mori Y, Eide PK, Deike K, Ringstad G. Human brain clearance imaging: Pathways taken by magnetic resonance imaging contrast agents after administration in cerebrospinal fluid and blood. NMR IN BIOMEDICINE 2024; 37:e5159. [PMID: 38634301 DOI: 10.1002/nbm.5159] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/04/2023] [Revised: 02/26/2024] [Accepted: 03/11/2024] [Indexed: 04/19/2024]
Abstract
Over the last decade, it has become evident that cerebrospinal fluid (CSF) plays a pivotal role in brain solute clearance through perivascular pathways and interactions between the brain and meningeal lymphatic vessels. Whereas most of this fundamental knowledge was gained from rodent models, human brain clearance imaging has provided important insights into the human system and highlighted the existence of important interspecies differences. Current gold standard techniques for human brain clearance imaging involve the injection of gadolinium-based contrast agents and monitoring their distribution and clearance over a period from a few hours up to 2 days. With both intrathecal and intravenous injections being used, which each have their own specific routes of distribution and thus clearance of contrast agent, a clear understanding of the kinetics associated with both approaches, and especially the differences between them, is needed to properly interpret the results. Because it is known that intrathecally injected contrast agent reaches the blood, albeit in small concentrations, and that similarly some of the intravenously injected agent can be detected in CSF, both pathways are connected and will, in theory, reach the same compartments. However, because of clear differences in relative enhancement patterns, both injection approaches will result in varying sensitivities for assessment of different subparts of the brain clearance system. In this opinion review article, the "EU Joint Programme - Neurodegenerative Disease Research (JPND)" consortium on human brain clearance imaging provides an overview of contrast agent pharmacokinetics in vivo following intrathecal and intravenous injections and what typical concentrations and concentration-time curves should be expected. This can be the basis for optimizing and interpreting contrast-enhanced MRI for brain clearance imaging. Furthermore, this can shed light on how molecules may exchange between blood, brain, and CSF.
Collapse
Affiliation(s)
- Matthias J P van Osch
- C. J. Gorter MRI Center, Department of Radiology, Leiden University Medical Center (LUMC), Leiden, The Netherlands
| | - Anders Wåhlin
- Department of Radiation Sciences, Radiation Physics, Biomedical Engineering, Umeå University, Umeå, Sweden
- Department of Applied Physics and Electronics, Umeå University, Umeå, Sweden
- Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden
| | - Paul Scheyhing
- Department of Neuroradiology, University Medical Center Bonn, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Ingrid Mossige
- Division of Radiology and Nuclear Medicine, Department of Physics and Computational Radiology, Oslo University Hospital, Oslo, Norway
- Institute of Clinical Medicine, The Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Lydiane Hirschler
- C. J. Gorter MRI Center, Department of Radiology, Leiden University Medical Center (LUMC), Leiden, The Netherlands
| | - Anders Eklund
- Department of Radiation Sciences, Radiation Physics, Biomedical Engineering, Umeå University, Umeå, Sweden
- Umeå Center for Functional Brain Imaging, Umeå University, Umeå, Sweden
| | - Klara Mogensen
- Department of Radiation Sciences, Radiation Physics, Biomedical Engineering, Umeå University, Umeå, Sweden
| | - Ryszard Gomolka
- Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
| | - Alexander Radbruch
- Department of Neuroradiology, University Medical Center Bonn, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Sara Qvarlander
- Department of Radiation Sciences, Radiation Physics, Biomedical Engineering, Umeå University, Umeå, Sweden
| | - Andreas Decker
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, New York, USA
| | - Yuki Mori
- Center for Translational Neuromedicine, University of Copenhagen, Copenhagen, Denmark
| | - Per Kristian Eide
- Department of Neurosurgery, Oslo University Hospital-Rikshospitalet, Oslo, Norway
- KG Jebsen Centre for Brain Fluid Research, Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Katerina Deike
- Department of Neuroradiology, University Medical Center Bonn, Rheinische Friedrich-Wilhelms-Universität Bonn, Bonn, Germany
- German Center for Neurodegenerative Diseases (DZNE), Bonn, Germany
| | - Geir Ringstad
- Department of Radiology, Oslo University Hospital-Rikshospitalet, Oslo, Norway
- Department of Geriatrics and Internal Medicine, Sorlandet Hospital, Arendal, Norway
| |
Collapse
|
2
|
Persson NDÅ, Lohela TJ, Mortensen KN, Rosenholm M, Li Q, Weikop P, Nedergaard M, Lilius TO. Anesthesia Blunts Carbon Dioxide Effects on Glymphatic Cerebrospinal Fluid Dynamics in Mechanically Ventilated Rats. Anesthesiology 2024; 141:338-352. [PMID: 38787687 DOI: 10.1097/aln.0000000000005039] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 05/26/2024]
Abstract
BACKGROUND Impaired glymphatic clearance of cerebral metabolic products and fluids contribute to traumatic and ischemic brain edema and neurodegeneration in preclinical models. Glymphatic perivascular cerebrospinal fluid flow varies between anesthetics possibly due to changes in vasomotor tone and thereby in the dynamics of the periarterial cerebrospinal fluid (CSF)-containing space. To better understand the influence of anesthetics and carbon dioxide levels on CSF dynamics, this study examined the effect of periarterial size modulation on CSF distribution by changing blood carbon dioxide levels and anesthetic regimens with opposing vasomotor influences: vasoconstrictive ketamine-dexmedetomidine (K/DEX) and vasodilatory isoflurane. METHODS End-tidal carbon dioxide (ETco2) was modulated with either supplemental inhaled carbon dioxide to reach hypercapnia (Etco2, 80 mmHg) or hyperventilation (Etco2, 20 mmHg) in tracheostomized and anesthetized female rats. Distribution of intracisternally infused radiolabeled CSF tracer 111In-diethylamine pentaacetate was assessed for 86 min in (1) normoventilated (Etco2, 40 mmHg) K/DEX; (2) normoventilated isoflurane; (3) hypercapnic K/DEX; and (4) hyperventilated isoflurane groups using dynamic whole-body single-photon emission tomography. CSF volume changes were assessed with magnetic resonance imaging. RESULTS Under normoventilation, cortical CSF tracer perfusion, perivascular space size around middle cerebral arteries, and intracranial CSF volume were higher under K/DEX compared with isoflurane (cortical maximum percentage of injected dose ratio, 2.33 [95% CI, 1.35 to 4.04]; perivascular size ratio 2.20 [95% CI, 1.09 to 4.45]; and intracranial CSF volume ratio, 1.90 [95% CI, 1.33 to 2.71]). Under isoflurane, tracer was directed to systemic circulation. Under K/DEX, the intracranial tracer distribution and CSF volume were uninfluenced by hypercapnia compared with normoventilation. Intracranial CSF tracer distribution was unaffected by hyperventilation under isoflurane despite a 28% increase in CSF volume around middle cerebral arteries. CONCLUSIONS K/DEX and isoflurane overrode carbon dioxide as a regulator of CSF flow. K/DEX could be used to preserve CSF space and dynamics in hypercapnia, whereas hyperventilation was insufficient to increase cerebral CSF perfusion under isoflurane. EDITOR’S PERSPECTIVE
Collapse
Affiliation(s)
- Niklas Daniel Åke Persson
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland; Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Terhi J Lohela
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland; Department of Anaesthesiology, Intensive Care and Pain Medicine, HUS Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| | - Kristian Nygaard Mortensen
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Marko Rosenholm
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Qianliang Li
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Pia Weikop
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - 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, New York
| | - Tuomas O Lilius
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland; Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland; Department of Emergency Medicine and Services, HUS Helsinki University Hospital and University of Helsinki, Helsinki, Finland
| |
Collapse
|
3
|
Hladky SB, Barrand MA. Regulation of brain fluid volumes and pressures: basic principles, intracranial hypertension, ventriculomegaly and hydrocephalus. Fluids Barriers CNS 2024; 21:57. [PMID: 39020364 PMCID: PMC11253534 DOI: 10.1186/s12987-024-00532-w] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/16/2023] [Accepted: 03/21/2024] [Indexed: 07/19/2024] Open
Abstract
The principles of cerebrospinal fluid (CSF) production, circulation and outflow and regulation of fluid volumes and pressures in the normal brain are summarised. Abnormalities in these aspects in intracranial hypertension, ventriculomegaly and hydrocephalus are discussed. The brain parenchyma has a cellular framework with interstitial fluid (ISF) in the intervening spaces. Framework stress and interstitial fluid pressure (ISFP) combined provide the total stress which, after allowing for gravity, normally equals intracerebral pressure (ICP) with gradients of total stress too small to measure. Fluid pressure may differ from ICP in the parenchyma and collapsed subarachnoid spaces when the parenchyma presses against the meninges. Fluid pressure gradients determine fluid movements. In adults, restricting CSF outflow from subarachnoid spaces produces intracranial hypertension which, when CSF volumes change very little, is called idiopathic intracranial hypertension (iIH). Raised ICP in iIH is accompanied by increased venous sinus pressure, though which is cause and which effect is unclear. In infants with growing skulls, restriction in outflow leads to increased head and CSF volumes. In adults, ventriculomegaly can arise due to cerebral atrophy or, in hydrocephalus, to obstructions to intracranial CSF flow. In non-communicating hydrocephalus, flow through or out of the ventricles is somehow obstructed, whereas in communicating hydrocephalus, the obstruction is somewhere between the cisterna magna and cranial sites of outflow. When normal outflow routes are obstructed, continued CSF production in the ventricles may be partially balanced by outflow through the parenchyma via an oedematous periventricular layer and perivascular spaces. In adults, secondary hydrocephalus with raised ICP results from obvious obstructions to flow. By contrast, with the more subtly obstructed flow seen in normal pressure hydrocephalus (NPH), fluid pressure must be reduced elsewhere, e.g. in some subarachnoid spaces. In idiopathic NPH, where ventriculomegaly is accompanied by gait disturbance, dementia and/or urinary incontinence, the functional deficits can sometimes be reversed by shunting or third ventriculostomy. Parenchymal shrinkage is irreversible in late stage hydrocephalus with cellular framework loss but may not occur in early stages, whether by exclusion of fluid or otherwise. Further studies that are needed to explain the development of hydrocephalus are outlined.
Collapse
Affiliation(s)
- Stephen B Hladky
- Department of Pharmacology, Tennis Court Rd, Cambridge, CB2 1PD, UK.
| | | |
Collapse
|
4
|
Smets NG, Strijkers GJ, Vinje V, Bakker ENTP. Cerebrospinal fluid turnover as a driver of brain clearance. NMR IN BIOMEDICINE 2024; 37:e5029. [PMID: 37658736 DOI: 10.1002/nbm.5029] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 05/03/2023] [Revised: 06/30/2023] [Accepted: 08/05/2023] [Indexed: 09/05/2023]
Abstract
Cerebrospinal fluid (CSF) has historically been considered to function as a sink for brain-derived waste disposal. Recent work suggested that CSF interacts even more intensely with brain tissue than previously recognized, through perivascular spaces that penetrate the brain. Cardiac pulsations, vasomotion, and respiration have been suggested to drive CSF flow in these perivascular spaces, thereby enhancing waste clearance. However, the intrinsic role of CSF production in relation to its distribution volume (turnover) is not an explicit component of recent concepts on brain clearance. Here, we review the work on CSF turnover and volume, focusing on preclinical evidence. Herein, we highlight the use of MRI in establishing CSF-related parameters. We describe the impact of sleep, effect of anesthesia, aging, and hypertension on CSF turnover, and how this relates to brain clearance. Evaluation of the available evidence suggests that CSF turnover is a major determinant in brain clearance. In addition, we propose that several putative drivers of brain clearance, but also conditions associated with impaired clearance, such as aging, may actually relate to altered CSF turnover.
Collapse
Affiliation(s)
- Nina G Smets
- Department of Biomedical Engineering and Physics, Amsterdam University Medical Center, location AMC, Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences Research Institute, Amsterdam, the Netherlands
- Amsterdam Neuroscience Research Institute, Amsterdam, the Netherlands
| | - Gustav J Strijkers
- Department of Biomedical Engineering and Physics, Amsterdam University Medical Center, location AMC, Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences Research Institute, Amsterdam, the Netherlands
| | | | - Erik N T P Bakker
- Department of Biomedical Engineering and Physics, Amsterdam University Medical Center, location AMC, Amsterdam, the Netherlands
- Amsterdam Cardiovascular Sciences Research Institute, Amsterdam, the Netherlands
- Amsterdam Neuroscience Research Institute, Amsterdam, the Netherlands
| |
Collapse
|
5
|
Chen Z, Lai JHC, Xu J, Zhang H, Huang J, Chan KWY. The effect of aquaporin-4 inhibition on cerebrospinal fluid-tissue water exchange in mouse brain detected by magnetization transfer indirect spin labeling MRI. NMR IN BIOMEDICINE 2024; 37:e5093. [PMID: 38163739 DOI: 10.1002/nbm.5093] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/25/2023] [Revised: 11/19/2023] [Accepted: 11/27/2023] [Indexed: 01/03/2024]
Abstract
The fluid transport of cerebrospinal fluid (CSF) and interstitial fluid in surrounding tissues plays an important role in the drainage pathway that facilitates waste clearance from the brain. This pathway is known as the glymphatic or perivascular system, and its functions are dependent on aquaporin-4 (AQP4). Recently, magnetization transfer indirect spin labeling (MISL) magnetic resonance imaging (MRI) has been proposed as a noninvasive and noncontrast-enhanced method for detecting water exchange between CSF and brain tissue. In this study, we first optimized the MISL sequence at preclinical 3 T MRI, and then studied the correlation of MISL in CSF with magnetization transfer (MT) in brain tissue, as well as the altered water exchange under AQP4 inhibition, using C57BL/6 mice. Results showed a strong correlation of MISL signal with MT signal. With the AQP4 inhibitor, we observed a significant decrease in MISL value (P < 0.05), suggesting that the hampered AQP4 activity led to decreased water exchange between CSF and brain tissue or the impairment of the glymphatic function. Overall, our findings demonstrate the potential application of MISL in assessing brain water exchange at 3 T MRI and its potential clinical translation.
Collapse
Affiliation(s)
- Zilin Chen
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Joseph H C Lai
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Jiadi Xu
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, Maryland, USA
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
| | - Hao Zhang
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
| | - Jianpan Huang
- Department of Diagnostic Radiology, The University of Hong Kong, Hong Kong, China
| | - Kannie W Y Chan
- Department of Biomedical Engineering, City University of Hong Kong, Hong Kong, China
- Russell H. Morgan Department of Radiology and Radiological Science, Johns Hopkins University School of Medicine, Baltimore, Maryland, USA
- Hong Kong Centre for Cerebro-Cardiovascular Health Engineering (COCHE), Hong Kong, China
- Tung Biomedical Sciences Centre (TBSC), Hong Kong, China
- City University of Hong Kong Shenzhen Research Institute, Shenzhen, China
| |
Collapse
|
6
|
Bork PAR, Hauglund NL, Mori Y, Møllgård K, Hjorth PG, Nedergaard M. Modeling of brain efflux: Constraints of brain surfaces. Proc Natl Acad Sci U S A 2024; 121:e2318444121. [PMID: 38598340 PMCID: PMC11032467 DOI: 10.1073/pnas.2318444121] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/23/2023] [Accepted: 03/04/2024] [Indexed: 04/12/2024] Open
Abstract
Fluid efflux from the brain plays an important role in solute waste clearance. Current experimental approaches provide little spatial information, and data collection is limited due to short duration or low frequency of sampling. One approach shows tracer efflux to be independent of molecular size, indicating bulk flow, yet also decelerating like simple membrane diffusion. In an apparent contradiction to this report, other studies point to tracer efflux acceleration. We here develop a one-dimensional advection-diffusion model to gain insight into brain efflux principles. The model is characterized by nine physiological constants and three efflux parameters for which we quantify prior uncertainty. Using Bayes' rule and the two efflux studies, we validate the model and calculate data-informed parameter distributions. The apparent contradictions in the efflux studies are resolved by brain surface boundaries being bottlenecks for efflux. To critically test the model, a custom MRI efflux assay measuring solute dispersion in tissue and release to cerebrospinal fluid was employed. The model passed the test with tissue bulk flow velocities in the range 60 to 190 [Formula: see text]m/h. Dimensional analysis identified three principal determinants of efflux, highlighting brain surfaces as a restricting factor for metabolite solute clearance.
Collapse
Affiliation(s)
- Peter A. R. Bork
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen2200Denmark
| | - Natalie L. Hauglund
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen2200Denmark
| | - Yuki Mori
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen2200Denmark
| | - Kjeld Møllgård
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen2200Denmark
| | - Poul G. Hjorth
- Department of Applied Mathematics and Computer Science, Technical University of Denmark, Lyngby2800Denmark
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen2200Denmark
| |
Collapse
|
7
|
Osuna-Ramos JF, Camberos-Barraza J, Torres-Mondragón LE, Rábago-Monzón ÁR, Camacho-Zamora A, Valdez-Flores MA, Angulo-Rojo CE, Guadrón-Llanos AM, Picos-Cárdenas VJ, Calderón-Zamora L, Magaña-Gómez JA, Norzagaray-Valenzuela CD, Cárdenas-Torres FI, De la Herrán-Arita AK. Interplay between the Glymphatic System and the Endocannabinoid System: Implications for Brain Health and Disease. Int J Mol Sci 2023; 24:17458. [PMID: 38139290 PMCID: PMC10743431 DOI: 10.3390/ijms242417458] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/17/2023] [Revised: 12/01/2023] [Accepted: 12/06/2023] [Indexed: 12/24/2023] Open
Abstract
The intricate mechanisms governing brain health and function have long been subjects of extensive investigation. Recent research has shed light on two pivotal systems, the glymphatic system and the endocannabinoid system, and their profound role within the central nervous system. The glymphatic system is a recently discovered waste clearance system within the brain that facilitates the efficient removal of toxic waste products and metabolites from the central nervous system. It relies on the unique properties of the brain's extracellular space and is primarily driven by cerebrospinal fluid and glial cells. Conversely, the endocannabinoid system, a multifaceted signaling network, is intricately involved in diverse physiological processes and has been associated with modulating synaptic plasticity, nociception, affective states, appetite regulation, and immune responses. This scientific review delves into the intricate interconnections between these two systems, exploring their combined influence on brain health and disease. By elucidating the synergistic effects of glymphatic function and endocannabinoid signaling, this review aims to deepen our understanding of their implications for neurological disorders, immune responses, and cognitive well-being.
Collapse
Affiliation(s)
- Juan F. Osuna-Ramos
- Faculty of Medicine, Autonomous University of Sinaloa, Culiacán 80019, Mexico
| | - Josué Camberos-Barraza
- Faculty of Medicine, Autonomous University of Sinaloa, Culiacán 80019, Mexico
- Doctorado en Biomedicina Molecular, Autonomous University of Sinaloa, Culiacán 80019, Mexico
| | - Laura E. Torres-Mondragón
- Faculty of Medicine, Autonomous University of Sinaloa, Culiacán 80019, Mexico
- Maestría en Biomedicina Molecular, Autonomous University of Sinaloa, Culiacán 80019, Mexico
| | - Ángel R. Rábago-Monzón
- Faculty of Medicine, Autonomous University of Sinaloa, Culiacán 80019, Mexico
- Doctorado en Biomedicina Molecular, Autonomous University of Sinaloa, Culiacán 80019, Mexico
| | | | | | | | | | | | | | - Javier A. Magaña-Gómez
- Faculty of Nutrition Sciences and Gastronomy, Autonomous University of Sinaloa, Culiacán 80019, Mexico
| | | | | | | |
Collapse
|
8
|
Zhu Y, Wang G, Kolluru C, Gu Y, Gao H, Zhang J, Wang Y, Wilson DL, Zhu X, Flask CA, Yu X. Transport pathways and kinetics of cerebrospinal fluid tracers in mouse brain observed by dynamic contrast-enhanced MRI. Sci Rep 2023; 13:13882. [PMID: 37620371 PMCID: PMC10449788 DOI: 10.1038/s41598-023-40896-x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/20/2023] [Accepted: 08/17/2023] [Indexed: 08/26/2023] Open
Abstract
Recent studies have suggested the glymphatic system as a key mechanism of waste removal in the brain. Dynamic contrast-enhanced MRI (DCE-MRI) using intracisternally administered contrast agents is a promising tool for assessing glymphatic function in the whole brain. In this study, we evaluated the transport kinetics and distribution of three MRI contrast agents with vastly different molecular sizes in mice. Our results demonstrate that oxygen-17 enriched water (H217O), which has direct access to parenchymal tissues via aquaporin-4 water channels, exhibited significantly faster and more extensive transport compared to the two gadolinium-based contrast agents (Gd-DTPA and GadoSpin). Time-lagged correlation and clustering analyses also revealed different transport pathways for Gd-DTPA and H217O. Furthermore, there were significant differences in transport kinetics of the three contrast agents to the lateral ventricles, reflecting the differences in forces that drive solute transport in the brain. These findings suggest the size-dependent transport pathways and kinetics of intracisternally administered contrast agents and the potential of DCE-MRI for assessing multiple aspects of solute transport in the glymphatic system.
Collapse
Affiliation(s)
- Yuran Zhu
- Department of Biomedical Engineering, Case Western Reserve University, Wickenden 430, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Guanhua Wang
- Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Chaitanya Kolluru
- Department of Biomedical Engineering, Case Western Reserve University, Wickenden 430, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Yuning Gu
- Department of Biomedical Engineering, Case Western Reserve University, Wickenden 430, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Huiyun Gao
- Cardiovascular Research Institute, Case Western Reserve University, Cleveland, OH, USA
- Department of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - Jing Zhang
- Department of Biostatistics, Population and Quantitative Health Sciences, Case Western Reserve University, Cleveland, OH, USA
| | - Yunmei Wang
- Cardiovascular Research Institute, Case Western Reserve University, Cleveland, OH, USA
- Department of Medicine, Case Western Reserve University, Cleveland, OH, USA
| | - David L Wilson
- Department of Biomedical Engineering, Case Western Reserve University, Wickenden 430, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
- Department of Radiology, Case Western Reserve University, Wickenden 430, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
| | - Xiaofeng Zhu
- Department of Biostatistics, Population and Quantitative Health Sciences, Case Western Reserve University, Cleveland, OH, USA
| | - Chris A Flask
- Department of Biomedical Engineering, Case Western Reserve University, Wickenden 430, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
- Department of Radiology, Case Western Reserve University, Wickenden 430, 10900 Euclid Avenue, Cleveland, OH, 44106, USA
- Department of Pediatrics, Case Western Reserve University, Cleveland, OH, USA
| | - Xin Yu
- Department of Biomedical Engineering, Case Western Reserve University, Wickenden 430, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.
- Department of Radiology, Case Western Reserve University, Wickenden 430, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.
- Department of Physiology and Biophysics, Case Western Reserve University, Wickenden 430, 10900 Euclid Avenue, Cleveland, OH, 44106, USA.
| |
Collapse
|
9
|
Sarker A, Suh M, Choi Y, Park JY, Lee YS, Lee DS. Intrathecal [ 64Cu]Cu-albumin PET reveals age-related decline of lymphatic drainage of cerebrospinal fluid. Sci Rep 2023; 13:12930. [PMID: 37558700 PMCID: PMC10412645 DOI: 10.1038/s41598-023-39903-y] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/18/2023] [Accepted: 08/01/2023] [Indexed: 08/11/2023] Open
Abstract
Age-related cognitive decline is associated with dysfunctional lymphatic drainage of cerebrospinal fluid (CSF) through meningeal lymphatic vessels. In this study, intrathecal [64Cu]Cu-albumin positron emission tomography (PET) was applied in mice to evaluate lymphatic drainage of CSF and its variation with age. [64Cu]Cu-albumin PET was performed at multiple time points after intrathecal injection of [64Cu]Cu-albumin at an infusion rate of 700 nl/min in adult and aged mice (15-25 months old). CSF clearance and paravertebral lymph nodes were quantified after injection and during the stationary phase. Stationary phase of the next day followed the initial perturbed state by injection of 6 ul (1/7 of total CSF volume) and CSF clearance half-time from the subarachnoid space was 93.4 ± 19.7 and 123.3 ± 15.6 min in adult and aged mice (p = 0.01), respectively. While the % injected dose of CSF space were higher, the activity of the paravertebral lymph nodes were lower in the aged mice on the next day. [64Cu]Cu-albumin PET enabled us to quantify CSF-lymphatic drainage across all levels of brain spinal cords and to visualize and quantify lymph node activity due to CSF drainage. [64Cu]Cu-albumin PET revealed the age-related decrease of the lymphatic drainage of CSF due to this decreased drainage from the subarachnoid space, especially during the stationary phase, in aged mice.
Collapse
Affiliation(s)
- Azmal Sarker
- Department of Nuclear Medicine, College of Medicine, Seoul National University, Seoul, Korea
| | - Minseok Suh
- Department of Nuclear Medicine, College of Medicine, Seoul National University, Seoul, Korea.
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea.
- Biomedical Research Center, Seoul National University Hospital, Seoul, Korea.
| | - Yoori Choi
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea
- Biomedical Research Center, Seoul National University Hospital, Seoul, Korea
- Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Korea
| | - Ji Yong Park
- Department of Nuclear Medicine, College of Medicine, Seoul National University, Seoul, Korea
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea
| | - Yun-Sang Lee
- Department of Nuclear Medicine, College of Medicine, Seoul National University, Seoul, Korea
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea
| | - Dong Soo Lee
- Department of Nuclear Medicine, College of Medicine, Seoul National University, Seoul, Korea.
- Department of Nuclear Medicine, Seoul National University Hospital, Seoul, Korea.
- Department of Molecular Medicine and Biopharmaceutical Sciences, Graduate School of Convergence Science and Technology, Seoul National University, Seoul, Korea.
- Medical Research Center, College of Medicine, Seoul National University, Seoul, Korea.
- Medical Science and Engineering, School of Convergence Science and Technology, Pohang University of Science and Technology (POSTECH), Pohang, Korea.
| |
Collapse
|
10
|
Mathiesen BK, Miyakoshi LM, Cederroth CR, Tserga E, Versteegh C, Bork PAR, Hauglund NL, Gomolka RS, Mori Y, Edvall NK, Rouse S, Møllgård K, Holt JR, Nedergaard M, Canlon B. Delivery of gene therapy through a cerebrospinal fluid conduit to rescue hearing in adult mice. Sci Transl Med 2023; 15:eabq3916. [PMID: 37379370 DOI: 10.1126/scitranslmed.abq3916] [Citation(s) in RCA: 10] [Impact Index Per Article: 10.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/06/2022] [Accepted: 06/09/2023] [Indexed: 06/30/2023]
Abstract
Inner ear gene therapy has recently effectively restored hearing in neonatal mice, but it is complicated in adulthood by the structural inaccessibility of the cochlea, which is embedded within the temporal bone. Alternative delivery routes may advance auditory research and also prove useful when translated to humans with progressive genetic-mediated hearing loss. Cerebrospinal fluid flow via the glymphatic system is emerging as a new approach for brain-wide drug delivery in rodents as well as humans. The cerebrospinal fluid and the fluid of the inner ear are connected via a bony channel called the cochlear aqueduct, but previous studies have not explored the possibility of delivering gene therapy via the cerebrospinal fluid to restore hearing in adult deaf mice. Here, we showed that the cochlear aqueduct in mice exhibits lymphatic-like characteristics. In vivo time-lapse magnetic resonance imaging, computed tomography, and optical fluorescence microscopy showed that large-particle tracers injected into the cerebrospinal fluid reached the inner ear by dispersive transport via the cochlear aqueduct in adult mice. A single intracisternal injection of adeno-associated virus carrying solute carrier family 17, member 8 (Slc17A8), which encodes vesicular glutamate transporter-3 (VGLUT3), rescued hearing in adult deaf Slc17A8-/- mice by restoring VGLUT3 protein expression in inner hair cells, with minimal ectopic expression in the brain and none in the liver. Our findings demonstrate that cerebrospinal fluid transport comprises an accessible route for gene delivery to the adult inner ear and may represent an important step toward using gene therapy to restore hearing in humans.
Collapse
Affiliation(s)
- Barbara K Mathiesen
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Denmark
| | - Leo M Miyakoshi
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Denmark
| | - Christopher R Cederroth
- Department of Physiology and Pharmacology, Karolinska Institutet, Solnavägen 9, Biomedicum, 171 65 Stockholm, Sweden
- Translational Hearing Research, Tübingen Hearing Research Center, Department of Otolaryngology, Head and Neck Surgery, University of Tübingen, Tübingen, Germany
| | - Evangelia Tserga
- Department of Physiology and Pharmacology, Karolinska Institutet, Solnavägen 9, Biomedicum, 171 65 Stockholm, Sweden
| | - Corstiaen Versteegh
- Department of Physiology and Pharmacology, Karolinska Institutet, Solnavägen 9, Biomedicum, 171 65 Stockholm, Sweden
| | - Peter A R Bork
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Denmark
| | - Natalie L Hauglund
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Denmark
| | - Ryszard Stefan Gomolka
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Denmark
| | - Yuki Mori
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Denmark
| | - Niklas K Edvall
- Department of Physiology and Pharmacology, Karolinska Institutet, Solnavägen 9, Biomedicum, 171 65 Stockholm, Sweden
| | - Stephanie Rouse
- Department of Otolaryngology and Neurology, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Kjeld Møllgård
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen; Copenhagen, 2200, Denmark
| | - Jeffrey R Holt
- Department of Otolaryngology and Neurology, Boston Children's Hospital and Harvard Medical School, Boston, MA 02115, USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Denmark
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Rochester Medical Center; Rochester, NY 14642, USA
| | - Barbara Canlon
- Department of Physiology and Pharmacology, Karolinska Institutet, Solnavägen 9, Biomedicum, 171 65 Stockholm, Sweden
| |
Collapse
|
11
|
Ding Z, Fan X, Zhang Y, Yao M, Wang G, Dong Y, Liu J, Song W. The glymphatic system: a new perspective on brain diseases. Front Aging Neurosci 2023; 15:1179988. [PMID: 37396658 PMCID: PMC10308198 DOI: 10.3389/fnagi.2023.1179988] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2023] [Accepted: 05/29/2023] [Indexed: 07/04/2023] Open
Abstract
The glymphatic system is a brain-wide perivascular pathway driven by aquaporin-4 on the endfeet of astrocytes, which can deliver nutrients and active substances to the brain parenchyma through periarterial cerebrospinal fluid (CSF) influx pathway and remove metabolic wastes through perivenous clearance routes. This paper summarizes the composition, overall fluid flow, solute transport, related diseases, affecting factors, and preclinical research methods of the glymphatic system. In doing so, we aim to provide direction and reference for more relevant researchers in the future.
Collapse
|
12
|
Spera I, Cousin N, Ries M, Kedracka A, Castillo A, Aleandri S, Vladymyrov M, Mapunda JA, Engelhardt B, Luciani P, Detmar M, Proulx ST. Open pathways for cerebrospinal fluid outflow at the cribriform plate along the olfactory nerves. EBioMedicine 2023; 91:104558. [PMID: 37043871 PMCID: PMC10119713 DOI: 10.1016/j.ebiom.2023.104558] [Citation(s) in RCA: 17] [Impact Index Per Article: 17.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/07/2022] [Revised: 02/23/2023] [Accepted: 03/24/2023] [Indexed: 04/14/2023] Open
Abstract
BACKGROUND Routes along the olfactory nerves crossing the cribriform plate that extend to lymphatic vessels within the nasal cavity have been identified as a critical cerebrospinal fluid (CSF) outflow pathway. However, it is still unclear how the efflux pathways along the nerves connect to lymphatic vessels or if any functional barriers are present at this site. The aim of this study was to anatomically define the connections between the subarachnoid space and the lymphatic system at the cribriform plate in mice. METHODS PEGylated fluorescent microbeads were infused into the CSF space in Prox1-GFP reporter mice and decalcification histology was utilized to investigate the anatomical connections between the subarachnoid space and the lymphatic vessels in the nasal submucosa. A fluorescently-labelled antibody marking vascular endothelium was injected into the cisterna magna to demonstrate the functionality of the lymphatic vessels in the olfactory region. Finally, we performed immunostaining to study the distribution of the arachnoid barrier at the cribriform plate region. FINDINGS We identified that there are open and direct connections from the subarachnoid space to lymphatic vessels enwrapping the olfactory nerves as they cross the cribriform plate towards the nasal submucosa. Furthermore, lymphatic vessels adjacent to the olfactory bulbs form a continuous network that is functionally connected to lymphatics in the nasal submucosa. Immunostainings revealed a discontinuous distribution of the arachnoid barrier at the olfactory region of the mouse. INTERPRETATION Our data supports a direct bulk flow mechanism through the cribriform plate allowing CSF drainage into nasal submucosal lymphatics in mice. FUNDING This study was supported by the Swiss National Science Foundation (310030_189226), Dementia Research Switzerland-Synapsis Foundation, the Heidi Seiler Stiftung and the Fondation Dr. Corinne Schuler.
Collapse
Affiliation(s)
- Irene Spera
- Theodor Kocher Institute, University of Bern, Bern, Switzerland
| | - Nikola Cousin
- Institute of Pharmaceutical Sciences, ETH Zürich, Zürich, Switzerland
| | - Miriam Ries
- Institute of Pharmaceutical Sciences, ETH Zürich, Zürich, Switzerland
| | - Anna Kedracka
- Institute of Pharmaceutical Sciences, ETH Zürich, Zürich, Switzerland
| | - Alina Castillo
- Theodor Kocher Institute, University of Bern, Bern, Switzerland
| | - Simone Aleandri
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | | | | | | | - Paola Luciani
- Department of Chemistry, Biochemistry and Pharmaceutical Sciences, University of Bern, Bern, Switzerland
| | - Michael Detmar
- Institute of Pharmaceutical Sciences, ETH Zürich, Zürich, Switzerland
| | - Steven T Proulx
- Theodor Kocher Institute, University of Bern, Bern, Switzerland.
| |
Collapse
|
13
|
Georgakopoulou T, van der Wijk AE, van Bavel E, Bakker ENTP. Perivascular clearance of blood proteins after blood-brain barrier disruption in a rat model of microinfarcts. Microvasc Res 2023; 148:104515. [PMID: 36893583 DOI: 10.1016/j.mvr.2023.104515] [Citation(s) in RCA: 2] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/24/2022] [Revised: 02/15/2023] [Accepted: 03/01/2023] [Indexed: 03/09/2023]
Abstract
Microinfarcts result in a transient loss of the blood-brain barrier (BBB) in the ischemic territory. This leads to the extravasation of blood proteins into the brain parenchyma. It is not clear how these proteins are removed. Here we studied the role of perivascular spaces in brain clearance from extravasated blood proteins. Male and female Wistar rats were infused with microspheres of either 15, 25, or 50 μm in diameter (n = 6 rats per group) via the left carotid artery. We infused either 25,000 microspheres of 15 μm, 5500 of 25 μm, or 1000 of 50 μm. One day later, rats were infused with lectin and hypoxyprobe to label perfused blood vessels and hypoxic areas, respectively. Rats were then euthanized and perfusion-fixed. Brains were excised, sectioned, and analyzed using immunostaining and confocal imaging. Microspheres induced a size-dependent increase in ischemic volume per territory, but the cumulative ischemic volume was similar in all groups. The total volumes of ischemia, hypoxia and infarction affected 1-2 % of the left hemisphere. Immunoglobulins (IgG) were present in ischemic brain tissue surrounding lodged microspheres in all groups. In addition, staining for IgG was found in perivascular spaces of blood vessels nearby areas of BBB disruption. About 2/3 of these vessels were arteries, while the remaining 1/3 of these vessels were veins. The subarachnoid space (SAS) of the affected hemisphere stained stronger for IgG than the contralateral hemisphere in all groups: +27 %, +44 % and +27 % respectively. Microspheres of various sizes induce a local loss of BBB integrity, evidenced by parenchymal IgG staining. The presence of IgG in perivascular spaces of both arteries and veins distinct from the ischemic territories suggests that both contribute to the removal of blood proteins. The strong staining for IgG in the SAS of the affected hemisphere suggests that this perivascular route egresses via the CSF. Perivascular spaces therefore play a previously unrecognized role in tissue clearance of fluid and extravasated proteins after BBB disruption induced by microinfarcts.
Collapse
Affiliation(s)
- Theodosia Georgakopoulou
- Amsterdam UMC Location University of Amsterdam, Biomedical Engineering and Physics, Meibergdreef 9, Amsterdam, the Netherlands
| | - Anne-Eva van der Wijk
- Amsterdam UMC Location University of Amsterdam, Biomedical Engineering and Physics, Meibergdreef 9, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Microcirculation, Amsterdam, the Netherlands
| | - Ed van Bavel
- Amsterdam UMC Location University of Amsterdam, Biomedical Engineering and Physics, Meibergdreef 9, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Microcirculation, Amsterdam, the Netherlands; Amsterdam Neuroscience, Neurovascular Disorders, Amsterdam, the Netherlands
| | - Erik N T P Bakker
- Amsterdam UMC Location University of Amsterdam, Biomedical Engineering and Physics, Meibergdreef 9, Amsterdam, the Netherlands; Amsterdam Cardiovascular Sciences, Microcirculation, Amsterdam, the Netherlands; Amsterdam Neuroscience, Neurovascular Disorders, Amsterdam, the Netherlands.
| |
Collapse
|
14
|
Lilius TO, Mortensen KN, Deville C, Lohela TJ, Stæger FF, Sigurdsson B, Fiordaliso EM, Rosenholm M, Kamphuis C, Beekman FJ, Jensen AI, Nedergaard M. Glymphatic-assisted perivascular brain delivery of intrathecal small gold nanoparticles. J Control Release 2023; 355:135-148. [PMID: 36731802 DOI: 10.1016/j.jconrel.2023.01.054] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/28/2022] [Revised: 11/05/2022] [Accepted: 01/18/2023] [Indexed: 02/04/2023]
Abstract
Nanoparticles are ultrafine particulate matter having considerable potential for treatment of central nervous system (CNS) disorders. Despite their tiny size, the blood-brain barrier (BBB) restricts their access to the CNS. Their direct cerebrospinal fluid (CSF) administration bypasses the BBB endothelium, but still fails to give adequate brain uptake. We present a novel approach for efficient CNS delivery of 111In-radiolabelled gold nanoparticles (AuNPs; 10-15 nm) via intra-cisterna magna administration, with tracking by SPECT imaging. To accelerate CSF brain influx, we administered AuNPs intracisternally in conjunction with systemic hypertonic saline, which dramatically increased the parenchymal AuNP uptake, especially in deep brain regions. AuNPs entered the CNS along periarterial spaces as visualized by MRI of gadolinium-labelled AuNPs and were cleared from brain within 24 h and excreted through the kidneys. Thus, the glymphatic-assisted perivascular network augment by systemic hypertonic saline is a pathway for highly efficient brain-wide distribution of small AuNPs.
Collapse
Affiliation(s)
- Tuomas O Lilius
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Department of Pharmacology, Faculty of Medicine, University of Helsinki, Helsinki, Finland; Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland; Department of Emergency Medicine and Services, University of Helsinki and Helsinki University Hospital, Finland
| | - Kristian Nygaard Mortensen
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Claire Deville
- The Hevesy Laboratory, Department of Health Technology, Technical University of Denmark, Roskilde, Denmark
| | - Terhi J Lohela
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland; Department of Anaesthesiology, Intensive Care Medicine, and Pain Medicine, University of Helsinki and Helsinki University Hospital, Finland
| | - Frederik Filip Stæger
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Björn Sigurdsson
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Elisabetta M Fiordaliso
- DTU Nanolab - National Center for Nano Fabrication and Characterization, Technical University of Denmark, Kgs. Lyngby, Denmark
| | - Marko Rosenholm
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark; Individualized Drug Therapy Research Program, Faculty of Medicine, University of Helsinki, Helsinki, Finland
| | - Chris Kamphuis
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands; MILabs B.V., Utrecht, the Netherlands
| | - Freek J Beekman
- Department of Translational Neuroscience, Brain Center Rudolf Magnus, University Medical Center Utrecht, Utrecht, the Netherlands; MILabs B.V., Utrecht, the Netherlands; Department of Radiation Science and Technology, Delft University of Technology, Delft, the Netherlands
| | - Andreas I Jensen
- The Hevesy Laboratory, Department of Health Technology, Technical University of Denmark, Roskilde, Denmark.
| | - 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.
| |
Collapse
|
15
|
Gomolka RS, Hablitz LM, Mestre H, Giannetto M, Du T, Hauglund NL, Xie L, Peng W, Martinez PM, Nedergaard M, Mori Y. Loss of aquaporin-4 results in glymphatic system dysfunction via brain-wide interstitial fluid stagnation. eLife 2023; 12:82232. [PMID: 36757363 PMCID: PMC9995113 DOI: 10.7554/elife.82232] [Citation(s) in RCA: 29] [Impact Index Per Article: 29.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/28/2022] [Accepted: 02/08/2023] [Indexed: 02/10/2023] Open
Abstract
The glymphatic system is a fluid transport network of cerebrospinal fluid (CSF) entering the brain along arterial perivascular spaces, exchanging with interstitial fluid (ISF), ultimately establishing directional clearance of interstitial solutes. CSF transport is facilitated by the expression of aquaporin-4 (AQP4) water channels on the perivascular endfeet of astrocytes. Mice with genetic deletion of AQP4 (AQP4 KO) exhibit abnormalities in the brain structure and molecular water transport. Yet, no studies have systematically examined how these abnormalities in structure and water transport correlate with glymphatic function. Here, we used high-resolution 3D magnetic resonance (MR) non-contrast cisternography, diffusion-weighted MR imaging (MR-DWI) along with intravoxel-incoherent motion (IVIM) DWI, while evaluating glymphatic function using a standard dynamic contrast-enhanced MR imaging to better understand how water transport and glymphatic function is disrupted after genetic deletion of AQP4. AQP4 KO mice had larger interstitial spaces and total brain volumes resulting in higher water content and reduced CSF space volumes, despite similar CSF production rates and vascular density compared to wildtype mice. The larger interstitial fluid volume likely resulted in increased slow but not fast MR diffusion measures and coincided with reduced glymphatic influx. This markedly altered brain fluid transport in AQP4 KO mice may result from a reduction in glymphatic clearance, leading to enlargement and stagnation of fluid in the interstitial space. Overall, diffusion MR is a useful tool to evaluate glymphatic function and may serve as valuable translational biomarker to study glymphatics in human disease.
Collapse
Affiliation(s)
| | - Lauren M Hablitz
- Center for Translational Neuromedicine, University of Rochester Medical CenterRochesterUnited States
| | - Humberto Mestre
- Center for Translational Neuromedicine, University of Rochester Medical CenterRochesterUnited States
- Department of Neurology, University of PennsylvaniaPhiladelphiaUnited States
| | - Michael Giannetto
- Center for Translational Neuromedicine, University of Rochester Medical CenterRochesterUnited States
| | - Ting Du
- Center for Translational Neuromedicine, University of Rochester Medical CenterRochesterUnited States
- School of Pharmacy, China Medical UniversityShenyangChina
| | | | - Lulu Xie
- Center for Translational Neuromedicine, University of Rochester Medical CenterRochesterUnited States
| | - Weiguo Peng
- Center for Translational Neuromedicine, University of CopenhagenCopenhagenDenmark
- Center for Translational Neuromedicine, University of Rochester Medical CenterRochesterUnited States
| | | | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of CopenhagenCopenhagenDenmark
- Center for Translational Neuromedicine, University of Rochester Medical CenterRochesterUnited States
| | - Yuki Mori
- Center for Translational Neuromedicine, University of CopenhagenCopenhagenDenmark
| |
Collapse
|
16
|
Zhu Y, Wang G, Kolluru C, Gu Y, Gao H, Zhang J, Wang Y, Wilson DL, Zhu X, Flask CA, Yu X. Transport Pathways and Kinetics of Cerebrospinal Fluid Tracers in Mouse Brain Observed by Dynamic Contrast-Enhanced MRI. RESEARCH SQUARE 2023:rs.3.rs-2544475. [PMID: 36798228 PMCID: PMC9934740 DOI: 10.21203/rs.3.rs-2544475/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Indexed: 02/10/2023]
Abstract
Background: Recent studies have suggested the glymphatic system as a solute transport pathway and waste removal mechanism in the brain. Imaging intracisternally administered tracers provides the opportunity of assessing various aspects of the glymphatic function. Dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) allows the evaluation of both the kinetics and spatial distribution of tracer transport in the whole brain. However, assessing mouse glymphatic function by DCE-MRI has been challenged by the small size of a mouse brain and the limited volume of fluids that can be delivered intracisternally without significantly altering the intracranial pressure. Further, previous studies in rats suggest that assessment of glymphatic function by DCE-MRI is dependent on the molecular size of the contrast agents. Methods: We established and validated an intracisternal infusion protocol in mice that allowed the measurements of the entire time course of contrast agent transport for 2 hours. The transport kinetics and distribution of three MRI contrast agents with drastically different molecular weights (MWs): Gd-DTPA (MW=661.8 Da, n=7), GadoSpin-P (MW=200 kDa, n=6), and oxygen-17 enriched water (H 2 17 O, MW=19 Da, n=7), were investigated. Results: The transport of H 2 17 O was significantly faster and more extensive than the two gadolinium-based contrast agents. Time-lagged correlation analysis and clustering analysis comparing the kinetics of Gd-DTPA and H 2 17 O transport also showed different cluster patterns and lag time between different regions of the brain, suggesting different transport pathways for H 2 17 O because of its direct access to parenchymal tissues via the aquaporin-4 water channels. Further, there were also significant differences in the transport kinetics of the three tracers to the lateral ventricles, which reflects the differences in forces that drive tracer transport in the brain. Conclusions: Comparison of the transport kinetics and distribution of three MRI contrast agents with different molecular sizes showed drastically different transport profiles and clustering patterns, suggesting that the transport pathways and kinetics in the glymphatic system are size-dependent.
Collapse
Affiliation(s)
| | | | | | | | | | | | | | | | | | | | - Xin Yu
- Case Western Reserve University
| |
Collapse
|
17
|
Could dexmedetomidine be repurposed as a glymphatic enhancer? Trends Pharmacol Sci 2022; 43:1030-1040. [PMID: 36280451 DOI: 10.1016/j.tips.2022.09.007] [Citation(s) in RCA: 8] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2022] [Revised: 09/26/2022] [Accepted: 09/26/2022] [Indexed: 11/06/2022]
Abstract
Cerebrospinal fluid (CSF) flows through the central nervous system (CNS) via the glymphatic pathway to clear the interstitium of metabolic waste. In preclinical studies, glymphatic fluid flow rate increases with low central noradrenergic tone and slow-wave activity during natural sleep and general anesthesia. By contrast, sleep deprivation reduces glymphatic clearance and leads to intracerebral accumulation of metabolic waste, suggesting an underlying mechanism linking sleep disturbances with neurodegenerative diseases. The selective α2-adrenergic agonist dexmedetomidine is a sedative drug that induces slow waves in the electroencephalogram, suppresses central noradrenergic tone, and preserves glymphatic outflow. As recently developed dexmedetomidine formulations enable self-administration, we suggest that dexmedetomidine could serve as a sedative-hypnotic drug to enhance clearance of harmful waste from the brain of those vulnerable to neurodegeneration.
Collapse
|
18
|
Lee H, Ozturk B, Stringer MS, Koundal S, MacIntosh BJ, Rothman D, Benveniste H. Choroid plexus tissue perfusion and blood to CSF barrier function in rats measured with continuous arterial spin labeling. Neuroimage 2022; 261:119512. [PMID: 35882269 PMCID: PMC9969358 DOI: 10.1016/j.neuroimage.2022.119512] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/08/2022] [Revised: 06/18/2022] [Accepted: 07/22/2022] [Indexed: 02/08/2023] Open
Abstract
The choroid plexus (ChP) of the cerebral ventricles is a source of cerebrospinal fluid (CSF) production and also plays a key role in immune surveillance at the level of blood-to-CSF-barrier (BCSFB). In this study, we quantify ChP blood perfusion and BCSFB mediated water exchange from arterial blood into ventricular CSF using non-invasive continuous arterial spin labelling magnetic resonance imaging (CASL-MRI). Systemic administration of anti-diuretic hormone (vasopressin) was used to validate BCSFB water flow as a metric of choroidal CSF secretory function. To further investigate the coupling between ChP blood perfusion and BCSFB water flow, we characterized the effects of two anesthetic regimens known to have large-scale differential effects on cerebral blood flow. For quantification of ChP blood perfusion a multi-compartment perfusion model was employed, and we discovered that partial volume correction improved measurement accuracy. Vasopressin significantly reduced both ChP blood perfusion and BCSFB water flow. ChP blood perfusion was significantly higher with pure isoflurane anesthesia (2-2.5%) when compared to a balanced anesthesia with dexmedetomidine and low-dose isoflurane (1.0 %), and significant correlation between ChP blood perfusion and BCSFB water flow was observed, however there was no significant difference in BCSFB water flow. In summary, here we introduce a non-invasive, robust, and spatially resolved in vivo imaging platform to quantify ChP blood perfusion as well as BCSFB water flow which can be applied to study coupling of these two key parameters in future clinical translational studies.
Collapse
Affiliation(s)
- Hedok Lee
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT, USA.
| | - Burhan Ozturk
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT, USA
| | - Michael S Stringer
- Brain Research Imaging Centre and UK Dementia Research Institute, Centre for Clinical Brain Sciences, University of Edinburgh, Edinburgh, UK
| | - Sunil Koundal
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT, USA
| | - Bradley J MacIntosh
- Department of Medical Biophysics, Faculty of Medicine, University of Toronto, Toronto, Canada
| | - Douglas Rothman
- Departments of Radiology and Biomedical Imaging, Yale School of Medicine, New Haven, CT, USA
| | - Helene Benveniste
- Department of Anesthesiology, Yale School of Medicine, New Haven, CT, USA
| |
Collapse
|
19
|
Abstract
We review theoretical and numerical models of the glymphatic system, which circulates cerebrospinal fluid and interstitial fluid around the brain, facilitating solute transport. Models enable hypothesis development and predictions of transport, with clinical applications including drug delivery, stroke, cardiac arrest, and neurodegenerative disorders like Alzheimer’s disease. We sort existing models into broad categories by anatomical function: Perivascular flow, transport in brain parenchyma, interfaces to perivascular spaces, efflux routes, and links to neuronal activity. Needs and opportunities for future work are highlighted wherever possible; new models, expanded models, and novel experiments to inform models could all have tremendous value for advancing the field.
Collapse
|
20
|
The glymphatic system: implications for drugs for central nervous system diseases. Nat Rev Drug Discov 2022; 21:763-779. [PMID: 35948785 DOI: 10.1038/s41573-022-00500-9] [Citation(s) in RCA: 38] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Accepted: 05/22/2022] [Indexed: 12/14/2022]
Abstract
In the past decade, evidence for a fluid clearance pathway in the central nervous system known as the glymphatic system has grown. According to the glymphatic system concept, cerebrospinal fluid flows directionally through the brain and non-selectively clears the interstitium of metabolic waste. Importantly, the glymphatic system may be modulated by particular drugs such as anaesthetics, as well as by non-pharmacological factors such as sleep, and its dysfunction has been implicated in central nervous system disorders such as Alzheimer disease. Although the glymphatic system is best described in rodents, reports using multiple neuroimaging modalities indicate that a similar transport system exists in the human brain. Here, we overview the evidence for the glymphatic system and its role in disease and discuss opportunities to harness the glymphatic system therapeutically; for example, by improving the effectiveness of intrathecally delivered drugs.
Collapse
|
21
|
Keil SA, Braun M, O’Boyle R, Sevao M, Pedersen T, Agarwal S, Jansson D, Iliff JJ. Dynamic infrared imaging of cerebrospinal fluid tracer influx into the brain. NEUROPHOTONICS 2022; 9:031915. [PMID: 35602461 PMCID: PMC9113559 DOI: 10.1117/1.nph.9.3.031915] [Citation(s) in RCA: 5] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/12/2021] [Accepted: 04/19/2022] [Indexed: 05/14/2023]
Abstract
Significance: The glymphatic system has been described recently as a series of perivascular channels that facilitate fluid exchange and solute clearance in the brain. Glymphatic dysfunction has been implicated in numerous pathological conditions, including Alzheimer's disease, traumatic brain injury, and stroke. Existing methods for assessing glymphatic function have been challenging: dynamic methods, such as two-photon microscopy and contrast-enhanced magnetic resonance imaging require expensive instrumentation and specific technical skills; slice-based fluorescent imaging is more readily implemented but lacks temporal resolution. Aim: To develop a straightforward and adaptable dynamic imaging approach for assessing glymphatic function in vivo in mice. Approach: Using a widely available small animal infrared (IR) imaging system (LICOR Pearl), visualization of IR cerebrospinal fluid tracer distribution over the cortical surface enables time-resolved measurement of the dynamics of glymphatic exchange. Using co-injection of IR and conventional fixable fluorescent tracers, dynamic imaging can be paired with whole-slice fluorescence imaging, permitting the quantification of glymphatic function throughout the brain as well as subsequent histological assessment. Results: These techniques were validated against one another, comparing differences between animals anesthetized with ketamine/xylazine and isoflurane. Conclusions: This technique permits sensitive dynamic imaging of glymphatic function, with the concurrent visualization of resolution of deeper structures.
Collapse
Affiliation(s)
- Samantha A. Keil
- VA Puget Sound Health Care System, VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), Seattle, Washington, United States
- University of Washington School of Medicine, Department of Psychiatry and Behavioral Sciences, Seattle, Washington, United States
| | - Molly Braun
- VA Puget Sound Health Care System, VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), Seattle, Washington, United States
- University of Washington School of Medicine, Department of Psychiatry and Behavioral Sciences, Seattle, Washington, United States
| | - Ryan O’Boyle
- VA Puget Sound Health Care System, VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), Seattle, Washington, United States
| | - Mathew Sevao
- VA Puget Sound Health Care System, VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), Seattle, Washington, United States
| | - Taylor Pedersen
- VA Puget Sound Health Care System, VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), Seattle, Washington, United States
| | - Sanjana Agarwal
- VA Puget Sound Health Care System, VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), Seattle, Washington, United States
| | - Deidre Jansson
- VA Puget Sound Health Care System, VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), Seattle, Washington, United States
- University of Washington School of Medicine, Department of Psychiatry and Behavioral Sciences, Seattle, Washington, United States
| | - Jeffrey J. Iliff
- VA Puget Sound Health Care System, VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), Seattle, Washington, United States
- University of Washington School of Medicine, Department of Psychiatry and Behavioral Sciences, Seattle, Washington, United States
- University of Washington School of Medicine, Department of Neurology, Seattle, Washington, United States
| |
Collapse
|
22
|
Lindhardt TB, Gutiérrez-Jiménez E, Liang Z, Hansen B. Male and Female C57BL/6 Mice Respond Differently to Awake Magnetic Resonance Imaging Habituation. Front Neurosci 2022; 16:853527. [PMID: 35757553 PMCID: PMC9226328 DOI: 10.3389/fnins.2022.853527] [Citation(s) in RCA: 12] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/12/2022] [Accepted: 05/18/2022] [Indexed: 01/20/2023] Open
Abstract
Traditionally, preclinical magnetic resonance imaging (MRI) has been performed in anesthetized animals. However, anesthesia has been shown to perturb normal brain function and physiology. Such effects limit our ability to detect subtle physiological alterations in disease models and treatment studies, thus hampering discovery and compromising generality of findings. Therefore, methods for awake animal MRI are needed to study the rodent brain in its natural physiological state, free of anesthetics. Current setups for awake animal MRI rely on restraining systems to avoid animal movement during scanning. To reduce restraint stress, animals are habituated to the scanner environment prior to MRI data collection. To date, however, most awake MRI studies employ male rodents only. This is a fundamental limitation as results obtained may be pertinent only to half of the population. We characterized training and habituation responses of male and female mice to provide improved, sex-dependent training procedures for awake mouse MRI. We recorded heart rate, monitored behavioral responses (body weight and fecal boli weight) and fecal corticosterone levels (FCM) as indicators of wellbeing and stress during a 14-day progressive habituation protocol. In addition, we also assessed discomfort levels and anxiety using the mouse grimace scale (MGS) and light/dark test (LDT), respectively. All scores were compared between both groups. We found that heart rate was significantly decreased after 10 and 11 days of training for both males and females, respectively. However, the specific time course for this decrease was significantly different between males and females, and females exhibited higher anxiety levels during habituation and 14 days after habituation than males. Lastly, we also found that mean FCM levels for both groups were decreased after 11 days of MRI habituation. The present work shows that mice can be successfully trained for extended MRI sessions which is necessary for many (particularly non-fMRI) studies. Importantly, we find that males and females differ in their response to awake MRI habituation, which should be considered in future awake MRI studies that aim to include male and female mice.
Collapse
Affiliation(s)
- Thomas Beck Lindhardt
- Department of Clinical Medicine, Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
| | - Eugenio Gutiérrez-Jiménez
- Department of Clinical Medicine, Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
| | - Zhifeng Liang
- CAS Center for Excellence in Brain Sciences and Intelligence Technology, Institute of Neuroscience, Chinese Academy of Sciences, Shanghai, China
| | - Brian Hansen
- Department of Clinical Medicine, Center of Functionally Integrative Neuroscience, Aarhus University, Aarhus, Denmark
| |
Collapse
|
23
|
Boster KAS, Tithof J, Cook DD, Thomas JH, Kelley DH. Sensitivity analysis on a network model of glymphatic flow. J R Soc Interface 2022; 19:20220257. [PMID: 35642425 DOI: 10.1098/rsif.2022.0257] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/24/2022] Open
Abstract
Intracranial cerebrospinal and interstitial fluid (ISF) flow and solute transport have important clinical implications, but limited in vivo access to the brain interior leaves gaping holes in human understanding of the nature of these neurophysiological phenomena. Models can address some gaps, but only insofar as model inputs are accurate. We perform a sensitivity analysis using a Monte Carlo approach on a lumped-parameter network model of cerebrospinal and ISF in perivascular and extracellular spaces in the murine brain. We place bounds on model predictions given the uncertainty in input parameters. Péclet numbers for transport in penetrating perivascular spaces (PVSs) and within the parenchyma are separated by at least two orders of magnitude. Low permeability in penetrating PVSs requires unrealistically large driving pressure and/or results in poor perfusion and are deemed unlikely. The model is most sensitive to the permeability of penetrating PVSs, a parameter whose value is largely unknown, highlighting an important direction for future experiments. Until the value of the permeability of penetrating PVSs is more accurately measured, the uncertainty of any model that includes flow in penetrating PVSs is so large that absolute numbers have little meaning and practical application is limited.
Collapse
Affiliation(s)
- Kimberly A S Boster
- Department of Mechanical Engineering, University of Rochester, Rochester, NY 14627, USA
| | - Jeffrey Tithof
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN 55455, USA
| | - Douglas D Cook
- Department of Mechanical Engineering, Brigham Young University, Provo, UT 84602, USA
| | - John H Thomas
- Department of Mechanical Engineering, University of Rochester, Rochester, NY 14627, USA
| | - Douglas H Kelley
- Department of Mechanical Engineering, University of Rochester, Rochester, NY 14627, USA
| |
Collapse
|
24
|
Uselman TW, Medina CS, Gray HB, Jacobs RE, Bearer EL. Longitudinal manganese-enhanced magnetic resonance imaging of neural projections and activity. NMR IN BIOMEDICINE 2022; 35:e4675. [PMID: 35253280 PMCID: PMC11064873 DOI: 10.1002/nbm.4675] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 07/28/2021] [Revised: 10/19/2021] [Accepted: 12/07/2021] [Indexed: 06/14/2023]
Abstract
Manganese-enhanced magnetic resonance imaging (MEMRI) holds exceptional promise for preclinical studies of brain-wide physiology in awake-behaving animals. The objectives of this review are to update the current information regarding MEMRI and to inform new investigators as to its potential. Mn(II) is a powerful contrast agent for two main reasons: (1) high signal intensity at low doses; and (2) biological interactions, such as projection tracing and neural activity mapping via entry into electrically active neurons in the living brain. High-spin Mn(II) reduces the relaxation time of water protons: at Mn(II) concentrations typically encountered in MEMRI, robust hyperintensity is obtained without adverse effects. By selectively entering neurons through voltage-gated calcium channels, Mn(II) highlights active neurons. Safe doses may be repeated over weeks to allow for longitudinal imaging of brain-wide dynamics in the same individual across time. When delivered by stereotactic intracerebral injection, Mn(II) enters active neurons at the injection site and then travels inside axons for long distances, tracing neuronal projection anatomy. Rates of axonal transport within the brain were measured for the first time in "time-lapse" MEMRI. When delivered systemically, Mn(II) enters active neurons throughout the brain via voltage-sensitive calcium channels and clears slowly. Thus behavior can be monitored during Mn(II) uptake and hyperintense signals due to Mn(II) uptake captured retrospectively, allowing pairing of behavior with neural activity maps for the first time. Here we review critical information gained from MEMRI projection mapping about human neuropsychological disorders. We then discuss results from neural activity mapping from systemic Mn(II) imaged longitudinally that have illuminated development of the tonotopic map in the inferior colliculus as well as brain-wide responses to acute threat and how it evolves over time. MEMRI posed specific challenges for image data analysis that have recently been transcended. We predict a bright future for longitudinal MEMRI in pursuit of solutions to the brain-behavior mystery.
Collapse
Affiliation(s)
- Taylor W. Uselman
- University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
| | | | - Harry B. Gray
- Beckman Institute, California Institute of Technology, Pasadena, California, USA
| | - Russell E. Jacobs
- Zilkha Neurogenetic Institute, Keck School of Medicine, University of Southern California, Los Angeles, California, USA
| | - Elaine L. Bearer
- University of New Mexico Health Sciences Center, Albuquerque, New Mexico, USA
- Beckman Institute, California Institute of Technology, Pasadena, California, USA
| |
Collapse
|
25
|
Tithof J, Boster KA, Bork PA, Nedergaard M, Thomas JH, Kelley DH. A network model of glymphatic flow under different experimentally-motivated parametric scenarios. iScience 2022; 25:104258. [PMID: 35521514 PMCID: PMC9062681 DOI: 10.1016/j.isci.2022.104258] [Citation(s) in RCA: 16] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/10/2021] [Revised: 02/08/2022] [Accepted: 04/08/2022] [Indexed: 12/04/2022] Open
Abstract
Flow of cerebrospinal fluid (CSF) through perivascular spaces (PVSs) in the brain delivers nutrients, clears metabolic waste, and causes edema formation. Brain-wide imaging cannot resolve PVSs, and high-resolution methods cannot access deep tissue. However, theoretical models provide valuable insight. We model the CSF pathway as a network of hydraulic resistances, using published parameter values. A few parameters (permeability of PVSs and the parenchyma, and dimensions of PVSs and astrocyte endfoot gaps) have wide uncertainties, so we focus on the limits of their ranges by analyzing different parametric scenarios. We identify low-resistance PVSs and high-resistance parenchyma as the only scenario that satisfies three essential criteria: that the flow be driven by a small pressure drop, exhibit good CSF perfusion throughout the cortex, and exhibit a substantial increase in flow during sleep. Our results point to the most important parameters, such as astrocyte endfoot gap dimensions, to be measured in future experiments. We model the CSF pathway as a network of hydraulic resistances Predictions are bracketed by analyzing parametric scenarios for unknown parameters Low-resistance PVSs and high-resistance parenchyma produce realistic flows Astrocyte endfoot gap size is among the important parameters to be measured
Collapse
Affiliation(s)
- Jeffrey Tithof
- Department of Mechanical Engineering, University of Rochester, 235 Hopeman Building, Rochester 14627, NY, USA
- Department of Mechanical Engineering, University of Minnesota, 111 Church St SE, Minneapolis 55455, MN, USA
- Corresponding author
| | - Kimberly A.S. Boster
- Department of Mechanical Engineering, University of Rochester, 235 Hopeman Building, Rochester 14627, NY, USA
| | - Peter A.R. Bork
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Copenhagen, Denmark
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Blegdamsvej 3B, 2200 Copenhagen N, Copenhagen, Denmark
- Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, 601 Elmwood Avenue, Rochester 14642, NY, USA
| | - John H. Thomas
- Department of Mechanical Engineering, University of Rochester, 235 Hopeman Building, Rochester 14627, NY, USA
| | - Douglas H. Kelley
- Department of Mechanical Engineering, University of Rochester, 235 Hopeman Building, Rochester 14627, NY, USA
| |
Collapse
|
26
|
Juhler M, Hansen TS, Novrup HVG, MacAulay N, Munch TN. Hydrocephalus Study Design: Testing New Hypotheses in Clinical Studies and Bench-to-Bedside Research. World Neurosurg 2022; 161:424-431. [PMID: 35505563 DOI: 10.1016/j.wneu.2021.12.100] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Revised: 12/23/2021] [Accepted: 12/24/2021] [Indexed: 10/18/2022]
Abstract
In this article, we aimed to describe some of the currently most challenging problems in neurosurgical management of hydrocephalus and how these can be reasons for inspiration for and development of research. We chose 4 areas of focus: 2 dedicated to improvement of current treatments (shunt implant surgery and endoscopic hydrocephalus surgery) and 2 dedicated to emerging future treatment principles (molecular mechanisms of cerebrospinal fluid secretion and hydrocephalus genetics).
Collapse
Affiliation(s)
- Marianne Juhler
- Department of Neurosurgery, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark; Department of Neurosurgery, Aarhus University Hospital, Aarhus, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark.
| | | | - Hans V G Novrup
- Department of Neurosurgery, Aarhus University Hospital, Aarhus, Denmark
| | - Nanna MacAulay
- Department of Neuroscience, University of Copenhagen, Copenhagen, Denmark
| | - Tina Nørgaard Munch
- Department of Neurosurgery, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark; Department of Clinical Medicine, University of Copenhagen, Copenhagen, Denmark; Department of Epidemiology Research, Statens Serum Institut, Copenhagen, Denmark
| |
Collapse
|
27
|
Li AM, Chen L, Liu H, Li Y, Duan W, Xu J. Age-dependent cerebrospinal fluid-tissue water exchange detected by magnetization transfer indirect spin labeling MRI. Magn Reson Med 2022; 87:2287-2298. [PMID: 34958518 PMCID: PMC8847338 DOI: 10.1002/mrm.29137] [Citation(s) in RCA: 4] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/16/2021] [Revised: 12/06/2021] [Accepted: 12/10/2021] [Indexed: 01/29/2023]
Abstract
PURPOSE A non-invasive magnetization transfer indirect spin labeling (MISL) MRI method is developed to quantify the water exchange between cerebrospinal fluid (CSF) and other tissues in the brain and to examine the age-dependence of water exchange. METHOD In the pulsed MISL, we implemented a short selective pulse followed by a post-labeling delay before an MRI acquisition with a long echo time; in the continuous MISL, a train of saturation pulses was applied. MISL signal (∆Z) was obtained by the subtraction of the label MRI at -3.5 ppm from the control MRI at 200 ppm. CSF was extracted from the mouse ventricles for the MISL optimization and validation. Comparison between wild type (WT) and aquaporin-4 knockout (AQP4-/- ) mice was performed to examine the contributions of CSF water exchange, whereas its age-dependence was investigated by comparing the adult and young WT mice. RESULTS The pulsed MISL method observed that the MISL signal reached the maximum at 1.5 s. The continuous MISL method showed the highest MISL signal in the fourth ventricle (∆Z = 13.5% ± 1.4%), whereas the third ventricle and the lateral ventricles had similar MISL ∆Z values (∆Z = 12.0% ± 1.8%). Additionally, significantly lower ∆Z (9.3%-18.7% reduction) was found in all ventricles for the adult mice than those of the young mice (p < 0.02). For the AQP4-/- mice, the ∆Z values were 5.9%-8.3% smaller than those of the age-matched WT mice in the lateral and fourth ventricles, but were not significant. CONCLUSION The MISL method has a great potential to study CSF water exchange with the surrounding tissues in brain.
Collapse
Affiliation(s)
- Anna M. Li
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD 21205, USA
| | - Lin Chen
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD 21205, USA
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
- Department of Electronic Science, Fujian Provincial Key Laboratory of Plasma and Magnetic Resonance, School of Electronic Science and Engineering, National Model Microelectronics College, Xiamen University, Xiamen, China
| | - Hongshuai Liu
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Yuguo Li
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD 21205, USA
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Wenzhen Duan
- Division of Neurobiology, Department of Psychiatry and Behavioral Sciences, Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| | - Jiadi Xu
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD 21205, USA
- Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD 21205, USA
| |
Collapse
|
28
|
Pulous FE, Cruz-Hernández JC, Yang C, Kaya Ζ, Paccalet A, Wojtkiewicz G, Capen D, Brown D, Wu JW, Schloss MJ, Vinegoni C, Richter D, Yamazoe M, Hulsmans M, Momin N, Grune J, Rohde D, McAlpine CS, Panizzi P, Weissleder R, Kim DE, Swirski FK, Lin CP, Moskowitz MA, Nahrendorf M. Cerebrospinal fluid can exit into the skull bone marrow and instruct cranial hematopoiesis in mice with bacterial meningitis. Nat Neurosci 2022; 25:567-576. [PMID: 35501382 PMCID: PMC9081225 DOI: 10.1038/s41593-022-01060-2] [Citation(s) in RCA: 72] [Impact Index Per Article: 36.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/19/2021] [Accepted: 03/23/2022] [Indexed: 01/25/2023]
Abstract
Interactions between the immune and central nervous systems strongly influence brain health. Although the blood-brain barrier restricts this crosstalk, we now know that meningeal gateways through brain border tissues facilitate intersystem communication. Cerebrospinal fluid (CSF), which interfaces with the glymphatic system and thereby drains the brain's interstitial and perivascular spaces, facilitates outward signaling beyond the blood-brain barrier. In the present study, we report that CSF can exit into the skull bone marrow. Fluorescent tracers injected into the cisterna magna of mice migrate along perivascular spaces of dural blood vessels and then travel through hundreds of sub-millimeter skull channels into the calvarial marrow. During meningitis, bacteria hijack this route to invade the skull's hematopoietic niches and initiate cranial hematopoiesis ahead of remote tibial sites. As skull channels also directly provide leukocytes to meninges, the privileged sampling of brain-derived danger signals in CSF by regional marrow may have broad implications for inflammatory neurological disorders.
Collapse
Affiliation(s)
- Fadi E Pulous
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Jean C Cruz-Hernández
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Chongbo Yang
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Ζeynep Kaya
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Alexandre Paccalet
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Gregory Wojtkiewicz
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Diane Capen
- Program in Membrane Biology, Division of Nephrology, Department of Medicine, Harvard Medical School and Massachusetts General Hospital, Boston, MA, USA
| | - Dennis Brown
- Program in Membrane Biology, Division of Nephrology, Department of Medicine, Harvard Medical School and Massachusetts General Hospital, Boston, MA, USA
| | - Juwell W Wu
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Maximilian J Schloss
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Claudio Vinegoni
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Dmitry Richter
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Masahiro Yamazoe
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Maarten Hulsmans
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Noor Momin
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Jana Grune
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - David Rohde
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Cameron S McAlpine
- Cardiovascular Research Institute and Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
- Nash Family Department of Neuroscience, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Peter Panizzi
- Department of Drug Discovery and Development, Harrison School of Pharmacy, Auburn University, Auburn, AL, USA
| | - Ralph Weissleder
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA
| | - Dong-Eog Kim
- Molecular Imaging and Neurovascular Research Laboratory, Department of Neurology, Dongguk University College of Medicine, Goyang, South Korea
| | - Filip K Swirski
- Cardiovascular Research Institute and Department of Medicine, Icahn School of Medicine at Mount Sinai, New York, NY, USA
| | - Charles P Lin
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
- Wellman Center for Photomedicine, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
| | - Michael A Moskowitz
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
- Department of Neurology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
| | - Matthias Nahrendorf
- Center for Systems Biology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
- Department of Radiology, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
- Cardiovascular Research Center, Massachusetts General Hospital and Harvard Medical School, Boston, MA, USA.
- Department of Internal Medicine I, University Hospital Wuerzburg, Wuerzburg, Germany.
| |
Collapse
|
29
|
Abstract
The brain harbors a unique ability to, figuratively speaking, shift its gears. During wakefulness, the brain is geared fully toward processing information and behaving, while homeostatic functions predominate during sleep. The blood-brain barrier establishes a stable environment that is optimal for neuronal function, yet the barrier imposes a physiological problem; transcapillary filtration that forms extracellular fluid in other organs is reduced to a minimum in brain. Consequently, the brain depends on a special fluid [the cerebrospinal fluid (CSF)] that is flushed into brain along the unique perivascular spaces created by astrocytic vascular endfeet. We describe this pathway, coined the term glymphatic system, based on its dependency on astrocytic vascular endfeet and their adluminal expression of aquaporin-4 water channels facing toward CSF-filled perivascular spaces. Glymphatic clearance of potentially harmful metabolic or protein waste products, such as amyloid-β, is primarily active during sleep, when its physiological drivers, the cardiac cycle, respiration, and slow vasomotion, together efficiently propel CSF inflow along periarterial spaces. The brain's extracellular space contains an abundance of proteoglycans and hyaluronan, which provide a low-resistance hydraulic conduit that rapidly can expand and shrink during the sleep-wake cycle. We describe this unique fluid system of the brain, which meets the brain's requisites to maintain homeostasis similar to peripheral organs, considering the blood-brain-barrier and the paths for formation and egress of the CSF.
Collapse
Affiliation(s)
- Martin Kaag Rasmussen
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, Denmark
| | - Humberto Mestre
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, New York
| | - 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, New York
| |
Collapse
|
30
|
Li L, Ding G, Zhang L, Davoodi-Bojd E, Chopp M, Li Q, Zhang ZG, Jiang Q. Aging-Related Alterations of Glymphatic Transport in Rat: In vivo Magnetic Resonance Imaging and Kinetic Study. Front Aging Neurosci 2022; 14:841798. [PMID: 35360203 PMCID: PMC8960847 DOI: 10.3389/fnagi.2022.841798] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/22/2021] [Accepted: 02/18/2022] [Indexed: 11/23/2022] Open
Abstract
Objective Impaired glymphatic waste clearance function during brain aging leads to the accumulation of metabolic waste and neurotoxic proteins (e.g., amyloid-β, tau) which contribute to neurological disorders. However, how the age-related glymphatic dysfunction exerts its effects on different cerebral regions and affects brain waste clearance remain unclear. Methods We investigated alterations of glymphatic transport in the aged rat brain using dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) and advanced kinetic modeling. Healthy young (3-4 months) and aged (18-20 months) male rats (n = 12/group) underwent the identical MRI protocol, including T2-weighted imaging and 3D T1-weighted imaging with intracisternal administration of contrast agent (Gd-DTPA). Model-derived parameters of infusion rate and clearance rate, characterizing the kinetics of cerebrospinal fluid (CSF) tracer transport via the glymphatic system, were evaluated in multiple representative brain regions. Changes in the CSF-filled cerebral ventricles were measured using contrast-induced time signal curves (TSCs) in conjunction with structural imaging. Results Compared to the young brain, an overall impairment of glymphatic transport function was detected in the aged brain, evidenced by the decrease in both infusion and clearance rates throughout the brain. Enlarged ventricles in parallel with reduced efficiency in CSF transport through the ventricular regions were present in the aged brain. While the age-related glymphatic dysfunction was widespread, our kinetic quantification demonstrated that its impact differed considerably among cerebral regions with the most severe effect found in olfactory bulb, indicating the heterogeneous and regional preferential alterations of glymphatic function. Conclusion The robust suppression of glymphatic activity in the olfactory bulb, which serves as one of major efflux routes for brain waste clearance, may underlie, in part, age-related neurodegenerative diseases associated with neurotoxic substance accumulation. Our data provide new insight into the cerebral regional vulnerability to brain functional change with aging.
Collapse
Affiliation(s)
- Lian Li
- Department of Neurology, Henry Ford Health System, Detroit, MI, United States
| | - Guangliang Ding
- Department of Neurology, Henry Ford Health System, Detroit, MI, United States
| | - Li Zhang
- Department of Neurology, Henry Ford Health System, Detroit, MI, United States
| | | | - Michael Chopp
- Department of Neurology, Henry Ford Health System, Detroit, MI, United States
- Department of Physics, Oakland University, Rochester, MI, United States
| | - Qingjiang Li
- Department of Neurology, Henry Ford Health System, Detroit, MI, United States
| | - Zheng Gang Zhang
- Department of Neurology, Henry Ford Health System, Detroit, MI, United States
| | - Quan Jiang
- Department of Neurology, Henry Ford Health System, Detroit, MI, United States
| |
Collapse
|
31
|
Li AM, Xu J. Cerebrospinal fluid-tissue exchange revealed by phase alternate labeling with null recovery MRI. Magn Reson Med 2022; 87:1207-1217. [PMID: 34799860 PMCID: PMC8794537 DOI: 10.1002/mrm.29092] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2021] [Revised: 10/09/2021] [Accepted: 11/01/2021] [Indexed: 01/10/2023]
Abstract
PURPOSE To develop phase alternate labeling with null recovery (PALAN) MRI methods for the quantification of the water exchange between cerebrospinal fluid (CSF) and other surrounding tissues in the brain. METHOD In both T1 -PALAN and apparent diffusion coefficient (ADC)-PALAN MRI methods, the cerebrospinal fluid signal was nulled, whereas the partial recovery of other tissues with shorter T1 (T1 -PALAN) or lower ADC values (ADC-PALAN) was labeled by alternating the phase of pulses. The water exchange was extracted from the difference between the recovery curves of CSF with and without labeling. RESULTS Both T1 -PALAN and ADC-PALAN observed a rapid occurrence of CSF water exchange with the surrounding tissues at 67 ± 56 ms and 13 ± 2 ms transit times, respectively. The T1 and ADC-PALAN signal peaked at 1.5 s. The CSF water exchange was 1153 ± 270 mL/100 mL/min with T1 -PALAN in the third and lateral ventricles, which was higher than 891 ± 60 mL/100 mL/min obtained by ADC-PALAN. T1 -PALAN ∆S values for the rostral and caudal ventricles are 0.015 ± 0.013 and 0.034 ± 0.01 (p = 0.022, n = 5), whereas similar ΔS values in both rostral and caudal lateral ventricles were observed by ADC-PALAN (3.9 ± 1.9 × 10-3 vs 4.4 ± 1.4 × 10-3 ; p = 0.66 and n = 5). CONCLUSION The PALAN methods are suitable tools to study CSF water exchange across different compartments in the brain.
Collapse
Affiliation(s)
- Anna M. Li
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, USA
| | - Jiadi Xu
- F.M. Kirby Research Center for Functional Brain Imaging, Kennedy Krieger Research Institute, Baltimore, MD, USA,Russell H. Morgan Department of Radiology and Radiological Science, The Johns Hopkins University School of Medicine, Baltimore, MD, USA,Corresponding Author: Jiadi Xu, Ph.D., Kennedy Krieger Institute, The Johns Hopkins University School of Medicine, 707 N. Broadway, Baltimore, MD, 21205, , Tel: 443-923-9572, Fax: 443-923-9505
| |
Collapse
|
32
|
Abstract
Brain disease remains a significant health, social, and economic burden with a high failure rate of translation of therapeutics to the clinic. Nanotherapeutics have represented a promising area of technology investment to improve drug bioavailability and delivery to the brain, with several successes for nanotherapeutic use for central nervous system disease that are currently in the clinic. However, renewed and continued research on the treatment of neurological disorders is critically needed. We explore the challenges of drug delivery to the brain and the ways in which nanotherapeutics can overcome these challenges. We provide a summary and overview of general design principles that can be applied to nanotherapeutics for uptake and penetration in the brain. We next highlight remaining questions that limit the translational potential of nanotherapeutics for application in the clinic. Lastly, we provide recommendations for ongoing preclinical research to improve the overall success of nanotherapeutics against neurological disease. Expected final online publication date for the Annual Review of Chemical and Biomolecular Engineering, Volume 13 is October 2022. Please see http://www.annualreviews.org/page/journal/pubdates for revised estimates.
Collapse
Affiliation(s)
- Andrea Joseph
- Department of Obstetrics and Gynecology, University of Pennsylvania, Philadelphia, Pennsylvania, USA;
| | - Elizabeth Nance
- Department of Chemical Engineering, University of Washington, Seattle, Washington, USA;
| |
Collapse
|
33
|
Hladky SB, Barrand MA. The glymphatic hypothesis: the theory and the evidence. Fluids Barriers CNS 2022; 19:9. [PMID: 35115036 PMCID: PMC8815211 DOI: 10.1186/s12987-021-00282-z] [Citation(s) in RCA: 87] [Impact Index Per Article: 43.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2021] [Accepted: 10/15/2021] [Indexed: 12/13/2022] Open
Abstract
The glymphatic hypothesis proposes a mechanism for extravascular transport into and out of the brain of hydrophilic solutes unable to cross the blood-brain barrier. It suggests that there is a circulation of fluid carrying solutes inwards via periarterial routes, through the interstitium and outwards via perivenous routes. This review critically analyses the evidence surrounding the mechanisms involved in each of these stages. There is good evidence that both influx and efflux of solutes occur along periarterial routes but no evidence that the principal route of outflow is perivenous. Furthermore, periarterial inflow of fluid is unlikely to be adequate to provide the outflow that would be needed to account for solute efflux. A tenet of the hypothesis is that flow sweeps solutes through the parenchyma. However, the velocity of any possible circulatory flow within the interstitium is too small compared to diffusion to provide effective solute movement. By comparison the earlier classical hypothesis describing extravascular transport proposed fluid entry into the parenchyma across the blood-brain barrier, solute movements within the parenchyma by diffusion, and solute efflux partly by diffusion near brain surfaces and partly carried by flow along "preferred routes" including perivascular spaces, white matter tracts and subependymal spaces. It did not suggest fluid entry via periarterial routes. Evidence is still incomplete concerning the routes and fate of solutes leaving the brain. A large proportion of the solutes eliminated from the parenchyma go to lymph nodes before reaching blood but the proportions delivered directly to lymph or indirectly via CSF which then enters lymph are as yet unclear. In addition, still not understood is why and how the absence of AQP4 which is normally highly expressed on glial endfeet lining periarterial and perivenous routes reduces rates of solute elimination from the parenchyma and of solute delivery to it from remote sites of injection. Neither the glymphatic hypothesis nor the earlier classical hypothesis adequately explain how solutes and fluid move into, through and out of the brain parenchyma. Features of a more complete description are discussed. All aspects of extravascular transport require further study.
Collapse
Affiliation(s)
- Stephen B. Hladky
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD UK
| | - Margery A. Barrand
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD UK
| |
Collapse
|
34
|
Tazoe J, Lu CF, Hsieh BY, Chen CY, Kao YCJ. Altered diffusivity of the subarachnoid cisterns in the rat brain following neurological disorders. Biomed J 2022; 46:134-143. [PMID: 35066210 PMCID: PMC10104961 DOI: 10.1016/j.bj.2022.01.006] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/31/2021] [Revised: 12/20/2021] [Accepted: 01/10/2022] [Indexed: 11/02/2022] Open
Abstract
BACKGROUND Although changes in diffusion characteristics of the brain parenchyma in neurological disorders are widely studied and used in clinical practice, the change in diffusivity in the cerebrospinal fluid (CSF) system is rarely reported. In this study, free water diffusion in the subarachnoid cisterns and ventricles of the rat brain was examined using diffusion magnetic resonance imaging (MRI), and the effects of neurological disorders on diffusivity in CSF system were investigated. METHODS Diffusion MRI and T2-weighted images were obtained in the intact rats, 24 h after ischemic stroke, and 50 days after mild traumatic brain injury (mTBI). We conducted the assessment of diffusivity in the rat brain in the subarachnoid cisterns around the midbrain, as well as the lateral ventricles. One-way ANOVA and Kruskal-Wallis test were used to evaluate the change in mean diffusivity (MD) and MD histogram, respectively, in CSF system following different neurological disease. RESULTS A significant decrease in the mean MD value of the subarachnoid cisterns was observed in the stroke rats compared with the intact and mTBI rats (p < 0.005). In addition, the skewness (p < 0.002), maximum MD (p < 0.002), and MD percentiles (p < 0.002) in the stroke rats differed significantly from those in the intact and mTBI rats. By contrast, no difference was observed in the mean MD value of the lateral ventricles among three groups of rats. We proposed that the assessment of the subarachnoid cisterns, rather than the lateral ventricles, in the rat brain would be useful in providing diffusion information in the CSF system. CONCLUSIONS Alterations in MD parameters of the subarachnoid cisterns after stroke provide evidence that brain injury may alter the characteristics of free water diffusion not only in the brain parenchyma but also in the CSF system.
Collapse
|
35
|
Szczygielski J, Kopańska M, Wysocka A, Oertel J. Cerebral Microcirculation, Perivascular Unit, and Glymphatic System: Role of Aquaporin-4 as the Gatekeeper for Water Homeostasis. Front Neurol 2021; 12:767470. [PMID: 34966347 PMCID: PMC8710539 DOI: 10.3389/fneur.2021.767470] [Citation(s) in RCA: 21] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2021] [Accepted: 11/12/2021] [Indexed: 12/13/2022] Open
Abstract
In the past, water homeostasis of the brain was understood as a certain quantitative equilibrium of water content between intravascular, interstitial, and intracellular spaces governed mostly by hydrostatic effects i.e., strictly by physical laws. The recent achievements in molecular bioscience have led to substantial changes in this regard. Some new concepts elaborate the idea that all compartments involved in cerebral fluid homeostasis create a functional continuum with an active and precise regulation of fluid exchange between them rather than only serving as separate fluid receptacles with mere passive diffusion mechanisms, based on hydrostatic pressure. According to these concepts, aquaporin-4 (AQP4) plays the central role in cerebral fluid homeostasis, acting as a water channel protein. The AQP4 not only enables water permeability through the blood-brain barrier but also regulates water exchange between perivascular spaces and the rest of the glymphatic system, described as pan-cerebral fluid pathway interlacing macroscopic cerebrospinal fluid (CSF) spaces with the interstitial fluid of brain tissue. With regards to this, AQP4 makes water shift strongly dependent on active processes including changes in cerebral microcirculation and autoregulation of brain vessels capacity. In this paper, the role of the AQP4 as the gatekeeper, regulating the water exchange between intracellular space, glymphatic system (including the so-called neurovascular units), and intravascular compartment is reviewed. In addition, the new concepts of brain edema as a misbalance in water homeostasis are critically appraised based on the newly described role of AQP4 for fluid permeation. Finally, the relevance of these hypotheses for clinical conditions (including brain trauma and stroke) and for both new and old therapy concepts are analyzed.
Collapse
Affiliation(s)
- Jacek Szczygielski
- Department of Neurosurgery, Institute of Medical Sciences, University of Rzeszów, Rzeszów, Poland.,Department of Neurosurgery, Faculty of Medicine and Saarland University Medical Center, Saarland University, Homburg, Germany
| | - Marta Kopańska
- Department of Pathophysiology, Institute of Medical Sciences, University of Rzeszów, Rzeszów, Poland
| | - Anna Wysocka
- Chair of Internal Medicine and Department of Internal Medicine in Nursing, Faculty of Health Sciences, Medical University of Lublin, Lublin, Poland
| | - Joachim Oertel
- Department of Neurosurgery, Faculty of Medicine and Saarland University Medical Center, Saarland University, Homburg, Germany
| |
Collapse
|
36
|
Decker Y, Krämer J, Xin L, Müller A, Scheller A, Fassbender K, Proulx ST. Magnetic resonance imaging of cerebrospinal fluid outflow after low-rate lateral ventricle infusion in mice. JCI Insight 2021; 7:150881. [PMID: 34905509 PMCID: PMC8855808 DOI: 10.1172/jci.insight.150881] [Citation(s) in RCA: 18] [Impact Index Per Article: 6.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The anatomical routes for the clearance of cerebrospinal fluid (CSF) remain incompletely understood. However, recent evidence has given strong support for routes leading to lymphatic vessels. A current debate centers upon the routes through which CSF can access lymphatics, with evidence emerging for either direct routes to meningeal lymphatics or along cranial nerves to reach lymphatics outside the skull. Here, a method was established to infuse contrast agent into the ventricles using indwelling cannulae during imaging of mice at 2 and 12 months of age by magnetic resonance imaging. As expected, a significant decline in overall CSF turnover was found with aging. Quantifications demonstrated that the bulk of the contrast agent flowed from the ventricles to the subarachnoid space in the basal cisterns. Comparatively little contrast agent signal was found at the dorsal aspect of the skull. The imaging dynamics from the two cohorts revealed that the contrast agent cleared from the cranium through the cribriform plate to the nasopharyngeal lymphatics. On decalcified sections, we confirmed that fluorescentlylabeled ovalbumin drains through the cribriform plate and can be found within lymphatics surrounding the nasopharynx. In conclusion, routes leading to nasopharyngeal lymphatics appear to be a major efflux pathway for cranial CSF.
Collapse
Affiliation(s)
- Yann Decker
- Department of Neurology, Saarland University, Homburg, Germany
| | - Jonas Krämer
- Department of Neurology, Saarland University, Homburg, Germany
| | - Li Xin
- Theodor Kocher Institute, University of Bern, Bern, Switzerland
| | - Andreas Müller
- Clinic for Diagnostic and Interventional Radiology, Saarland University, Homburg, Germany
| | - Anja Scheller
- Department of Physiology, Saarland University, Homburg, Germany
| | | | - Steven T Proulx
- Theodor Kocher Institute, University of Bern, Bern, Switzerland
| |
Collapse
|
37
|
Ray LA, Pike M, Simon M, Iliff JJ, Heys JJ. Quantitative analysis of macroscopic solute transport in the murine brain. Fluids Barriers CNS 2021; 18:55. [PMID: 34876169 PMCID: PMC8650464 DOI: 10.1186/s12987-021-00290-z] [Citation(s) in RCA: 14] [Impact Index Per Article: 4.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/11/2021] [Accepted: 11/21/2021] [Indexed: 12/16/2022] Open
Abstract
BACKGROUND Understanding molecular transport in the brain is critical to care and prevention of neurological disease and injury. A key question is whether transport occurs primarily by diffusion, or also by convection or dispersion. Dynamic contrast-enhanced (DCE-MRI) experiments have long reported solute transport in the brain that appears to be faster than diffusion alone, but this transport rate has not been quantified to a physically relevant value that can be compared to known diffusive rates of tracers. METHODS In this work, DCE-MRI experimental data is analyzed using subject-specific finite-element models to quantify transport in different anatomical regions across the whole mouse brain. The set of regional effective diffusivities ([Formula: see text]), a transport parameter combining all mechanisms of transport, that best represent the experimental data are determined and compared to apparent diffusivity ([Formula: see text]), the known rate of diffusion through brain tissue, to draw conclusions about dominant transport mechanisms in each region. RESULTS In the perivascular regions of major arteries, [Formula: see text] for gadoteridol (550 Da) was over 10,000 times greater than [Formula: see text]. In the brain tissue, constituting interstitial space and the perivascular space of smaller blood vessels, [Formula: see text] was 10-25 times greater than [Formula: see text]. CONCLUSIONS The analysis concludes that convection is present throughout the brain. Convection is dominant in the perivascular space of major surface and branching arteries (Pe > 1000) and significant to large molecules (> 1 kDa) in the combined interstitial space and perivascular space of smaller vessels (not resolved by DCE-MRI). Importantly, this work supports perivascular convection along penetrating blood vessels.
Collapse
Affiliation(s)
- Lori A Ray
- Department of Chemical and Biological Engineering, Montana State University, Bozeman, USA
| | - Martin Pike
- Advanced Imaging Research Center, Oregon Health and Sciences University, Portland, USA
| | - Matthew Simon
- Department of Anesthesiology and Perioperative Medicine, Oregon Health and Science University, Portland, USA
- Neuroscience Graduate Program, Oregon Health and Science University, Portland, USA
- Denali Therapeutics, San Francisco, USA
| | - Jeffrey J Iliff
- VISN 20 Mental Illness Research, Education and Clinical Center (MIRECC), VA Puget Sound Health Care System, Seattle, USA
- Department of Psychiatry and Behavioral Sciences, University of Washington School of Medicine, Seattle, USA
- Department of Neurology, University of Washington School of Medicine, Seattle, USA
| | - Jeffrey J Heys
- Department of Chemical and Biological Engineering, Montana State University, Bozeman, USA.
| |
Collapse
|
38
|
Dhaya I, Griton M, Konsman JP. Magnetic resonance imaging under isoflurane anesthesia alters cortical cyclooxygenase-2 expression and glial cell morphology during sepsis-associated neurological dysfunction in rats. Animal Model Exp Med 2021; 4:249-260. [PMID: 34557651 PMCID: PMC8446714 DOI: 10.1002/ame2.12167] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/18/2020] [Accepted: 04/19/2021] [Indexed: 01/31/2023] Open
Abstract
Background Magnetic resonance imaging (MRI) of rodents combined with histology allows to determine what mechanisms underlie functional and structural brain changes during sepsis-associated encephalopathy. However, the effects of MRI performed in isoflurane-anesthetized rodents on modifications of the blood-brain barrier and the production of vasoactive prostaglandins and glia cells, which have been proposed to mediate sepsis-associated brain dysfunction, are unknown. Methods This study addressed the effect of MRI under isoflurane anesthesia on blood-brain barrier integrity, cyclooxygenase-2 expression, and glial cell activation during cecal ligature and puncture-induced sepsis-associated brain dysfunction in rats. Results Cecal ligature and puncture reduced food intake and the righting reflex. MRI under isoflurane anesthesia reduced blood-brain barrier breakdown, decreased circularity of white matter astrocytes, and increased neuronal cyclooxygenase-2 immunoreactivity in the cortex 24 hours after laparotomy. In addition, it annihilated cecal ligature and puncture-induced increased circularity of white matter microglia. MRI under isoflurane anesthesia, however, did not alter sepsis-associated perivascular cyclooxygenase-2 induction. Conclusion These findings indicate that MRI under isoflurane anesthesia of rodents can modify neurovascular and glial responses and should, therefore, be interpreted with caution.
Collapse
Affiliation(s)
- Ibtihel Dhaya
- INCIAInstitut de Neurosciences Cognitives et Intégratives d'AquitaineCNRS UMR 5287BordeauxFrance
- Univ. BordeauxINCIAUMR 5287BordeauxFrance
- Laboratoire de Neurophysiologie Fonctionnelle et PathologiesUR/11ES09Faculté des Sciences MathématiquesPhysiques et NaturellesUniversité de Tunis El ManarTunisTunisie
| | - Marion Griton
- INCIAInstitut de Neurosciences Cognitives et Intégratives d'AquitaineCNRS UMR 5287BordeauxFrance
- Univ. BordeauxINCIAUMR 5287BordeauxFrance
- Service de Réanimation Anesthésie NeurochirurgicaleCentre Hospitalier Universitaire (CHU) de BordeauxBordeauxFrance
| | - Jan Pieter Konsman
- INCIAInstitut de Neurosciences Cognitives et Intégratives d'AquitaineCNRS UMR 5287BordeauxFrance
- Univ. BordeauxINCIAUMR 5287BordeauxFrance
| |
Collapse
|
39
|
Wafford KA. Aberrant waste disposal in neurodegeneration: why improved sleep could be the solution. CEREBRAL CIRCULATION - COGNITION AND BEHAVIOR 2021; 2:100025. [PMID: 36324713 PMCID: PMC9616228 DOI: 10.1016/j.cccb.2021.100025] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/14/2021] [Revised: 08/11/2021] [Accepted: 08/12/2021] [Indexed: 06/16/2023]
Abstract
Sleep takes up a large percentage of our lives and the full functions of this state are still not understood. However, over the last 10 years a new and important function has emerged as a mediator of brain clearance. Removal of toxic metabolites and proteins from the brain parenchyma generated during waking activity and high levels of synaptic processing is critical to normal brain function and only enabled during deep sleep. Understanding of this process is revealing how impaired sleep contributes an important and likely causative role in the accumulation and aggregation of aberrant proteins such as β-amyloid and phosphorylated tau, as well as inflammation and neuronal damage. We are also beginning to understand how brain slow-wave activity interacts with vascular function allowing the flow of CSF and interstitial fluid to drain into the body's lymphatic system. New methodology is enabling visualization of this process in both animals and humans and is revealing how these processes break down during ageing and disease. With this understanding we can begin to envisage novel therapeutic approaches to the treatment of neurodegeneration, and how reversing sleep impairment in the correct manner may provide a way to slow these processes and improve brain function.
Collapse
Key Words
- AQP4, aquaporin-4
- Alzheimer's disease
- Amyloid
- Aquaporin-4
- Astrocyte
- Aβ, beta amyloid
- BOLD, blood-oxygen level dependent imaging
- CAA, cerebral amyloid angiopathy
- CSF, Cerebrospinal fluid
- Clearance
- EEG, electroencephalography
- EMG, electromyography
- Glymphatic
- ISF, interstitial fluid
- MCI, mild cognitive impairment
- MRI, magnetic resonance imaging
- NOS, nitric oxide synthase
- NREM, non-rapid eye movement
- OSA, obstructive sleep apnea
- PET, positron emission tomography
- REM, rapid-eye movement
- SWA, slow wave activity
- SWS, slow-wave sleep
- Slow-wave sleep
- iNPH, idiopathic normal pressure hydrocephalus
Collapse
|
40
|
Raghunandan A, Ladron-de-Guevara A, Tithof J, Mestre H, Du T, Nedergaard M, Thomas JH, Kelley DH. Bulk flow of cerebrospinal fluid observed in periarterial spaces is not an artifact of injection. eLife 2021; 10:65958. [PMID: 33687330 PMCID: PMC7979157 DOI: 10.7554/elife.65958] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/20/2020] [Accepted: 03/08/2021] [Indexed: 12/24/2022] Open
Abstract
Cerebrospinal fluid (CSF) flowing through periarterial spaces is integral to the brain’s mechanism for clearing metabolic waste products. Experiments that track tracer particles injected into the cisterna magna (CM) of mouse brains have shown evidence of pulsatile CSF flow in perivascular spaces surrounding pial arteries, with a bulk flow in the same direction as blood flow. However, the driving mechanism remains elusive. Several studies have suggested that the bulk flow might be an artifact, driven by the injection itself. Here, we address this hypothesis with new in vivo experiments where tracer particles are injected into the CM using a dual-syringe system, with simultaneous injection and withdrawal of equal amounts of fluid. This method produces no net increase in CSF volume and no significant increase in intracranial pressure. Yet, particle-tracking reveals flows that are consistent in all respects with the flows observed in earlier experiments with single-syringe injection.
Collapse
Affiliation(s)
- Aditya Raghunandan
- Department of Mechanical Engineering, University of Rochester, Rochester, United States
| | - Antonio Ladron-de-Guevara
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, United States
| | - Jeffrey Tithof
- Department of Mechanical Engineering, University of Rochester, Rochester, United States.,Department of Mechanical Engineering, University of Minnesota, Minneapolis, United States
| | - Humberto Mestre
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, United States
| | - Ting Du
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, United States
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, United States.,Center for Translational Neuromedicine, University of Copenhagen, Rochester, United States
| | - John H Thomas
- Department of Mechanical Engineering, University of Rochester, Rochester, United States
| | - Douglas H Kelley
- Department of Mechanical Engineering, University of Rochester, Rochester, United States
| |
Collapse
|