1
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Kaag Rasmussen M, Møllgård K, Bork PAR, Weikop P, Esmail T, Drici L, Wewer Albrechtsen NJ, Carlsen JF, Huynh NPT, Ghitani N, Mann M, Goldman SA, Mori Y, Chesler AT, Nedergaard M. Trigeminal ganglion neurons are directly activated by influx of CSF solutes in a migraine model. Science 2024; 385:80-86. [PMID: 38963846 DOI: 10.1126/science.adl0544] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/27/2023] [Accepted: 05/01/2024] [Indexed: 07/06/2024]
Abstract
Classical migraine patients experience aura, which is transient neurological deficits associated with cortical spreading depression (CSD), preceding headache attacks. It is not currently understood how a pathological event in cortex can affect peripheral sensory neurons. In this study, we show that cerebrospinal fluid (CSF) flows into the trigeminal ganglion, establishing nonsynaptic signaling between brain and trigeminal cells. After CSD, ~11% of the CSF proteome is altered, with up-regulation of proteins that directly activate receptors in the trigeminal ganglion. CSF collected from animals exposed to CSD activates trigeminal neurons in naïve mice in part by CSF-borne calcitonin gene-related peptide (CGRP). We identify a communication pathway between the central and peripheral nervous system that might explain the relationship between migrainous aura and headache.
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Affiliation(s)
- Martin Kaag Rasmussen
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Kjeld Møllgård
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Peter A R Bork
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Pia Weikop
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Tina Esmail
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Lylia Drici
- NNF Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Nicolai J Wewer Albrechtsen
- NNF Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Department for Clinical Biochemistry, University Hospital Copenhagen - Bispebjerg, Copenhagen, 2400 Copenhagen, Denmark
| | - Jonathan Frederik Carlsen
- Department of Clinical Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Department of Radiology, Copenhagen University Hospital-Rigshospitalet, 2100 Copenhagen, Denmark
| | - Nguyen P T Huynh
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY 14642, USA
- Sana Biotechnology, Cambridge, MA 02139, USA
| | - Nima Ghitani
- National Center for Complementary and Integrative Health (NCCIH), Bethesda, MD 20892, USA
| | - Matthias Mann
- NNF Center for Protein Research, Faculty of Health and Medical Sciences, University of Copenhagen, 2200 Copenhagen, Denmark
- Department of Proteomics and Signal Transduction, Max-Planck Institute of Biochemistry, 82152 Martinsried, Germany
| | - Steven A Goldman
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen, Denmark
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY 14642, USA
- Sana Biotechnology, Cambridge, MA 02139, USA
| | - Yuki Mori
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen, Denmark
| | - Alexander T Chesler
- National Center for Complementary and Integrative Health (NCCIH), Bethesda, MD 20892, USA
- National Institute of Neurological Disorders and Stroke, Bethesda, MD 20892, USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Copenhagen, 2200 Copenhagen, Denmark
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY 14642, USA
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2
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Perkins GD, Neumar R, Hsu CH, Hirsch KG, Aneman A, Becker LB, Couper K, Callaway CW, Hoedemaekers CWE, Lim SL, Meurer W, Olasveengen T, Sekhon MS, Skrifvars M, Soar J, Tsai MS, Vengamma B, Nolan JP. Improving Outcomes After Post-Cardiac Arrest Brain Injury: A Scientific Statement From the International Liaison Committee on Resuscitation. Resuscitation 2024:110196. [PMID: 38932555 DOI: 10.1016/j.resuscitation.2024.110196] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/28/2024]
Abstract
This scientific statement presents a conceptual framework for the pathophysiology of post-cardiac arrest brain injury, explores reasons for previous failure to translate preclinical data to clinical practice, and outlines potential paths forward. Post-cardiac arrest brain injury is characterized by 4 distinct but overlapping phases: ischemic depolarization, reperfusion repolarization, dysregulation, and recovery and repair. Previous research has been challenging because of the limitations of laboratory models; heterogeneity in the patient populations enrolled; overoptimistic estimation of treatment effects leading to suboptimal sample sizes; timing and route of intervention delivery; limited or absent evidence that the intervention has engaged the mechanistic target; and heterogeneity in postresuscitation care, prognostication, and withdrawal of life-sustaining treatments. Future trials must tailor their interventions to the subset of patients most likely to benefit and deliver this intervention at the appropriate time, through the appropriate route, and at the appropriate dose. The complexity of post-cardiac arrest brain injury suggests that monotherapies are unlikely to be as successful as multimodal neuroprotective therapies. Biomarkers should be developed to identify patients with the targeted mechanism of injury, to quantify its severity, and to measure the response to therapy. Studies need to be adequately powered to detect effect sizes that are realistic and meaningful to patients, their families, and clinicians. Study designs should be optimized to accelerate the evaluation of the most promising interventions. Multidisciplinary and international collaboration will be essential to realize the goal of developing effective therapies for post-cardiac arrest brain injury.
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3
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Plá V, Bitsika S, Giannetto MJ, Ladron-de-Guevara A, Gahn-Martinez D, Mori Y, Nedergaard M, Møllgård K. In response to "An "outer subarachnoid space": fact or artifact? A commentary on "Structural characterization of SLYM: a 4th meningeal membrane" fluids and barriers of the CNS (2023) 20:93 by V. Plá et al.". Fluids Barriers CNS 2024; 21:49. [PMID: 38831371 PMCID: PMC11149354 DOI: 10.1186/s12987-024-00540-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/05/2024] Open
Affiliation(s)
- Virginia Plá
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Styliani Bitsika
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Michael J Giannetto
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Antonio Ladron-de-Guevara
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Daniel Gahn-Martinez
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Yuki Mori
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
| | - Maiken Nedergaard
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark.
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA.
| | - Kjeld Møllgård
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark.
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4
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Sun B, Fang D, Li W, Li M, Zhu S. NIR-II nanoprobes for investigating the glymphatic system function under anesthesia and stroke injury. J Nanobiotechnology 2024; 22:200. [PMID: 38654299 DOI: 10.1186/s12951-024-02481-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/14/2024] [Accepted: 04/16/2024] [Indexed: 04/25/2024] Open
Abstract
The glymphatic system plays an important role in the transportation of cerebrospinal fluid (CSF) and the clearance of metabolite waste in brain. However, current imaging modalities for studying the glymphatic system are limited. Herein, we apply NIR-II nanoprobes with non-invasive and high-contrast advantages to comprehensively explore the function of glymphatic system in mice under anesthesia and cerebral ischemia-reperfusion injury conditions. Our results show that the supplement drug dexmedetomidine (Dex) enhances CSF influx in the brain, decreases its outflow to mandibular lymph nodes, and leads to significant differences in CSF accumulation pattern in the spine compared to isoflurane (ISO) alone, while both ISO and Dex do not affect the clearance of tracer-filled CSF into blood circulation. Notably, we confirm the compromised glymphatic function after cerebral ischemia-reperfusion injury, leading to impaired glymphatic influx and reduced glymphatic efflux. This technique has great potential to elucidate the underlying mechanisms between the glymphatic system and central nervous system diseases.
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Affiliation(s)
- Bin Sun
- Joint Laboratory of Opto-Functional Theranostics in Medicine and Chemistry, First Hospital of Jilin University, Changchun, 130021, China
- State Key Laboratory of Supramolecular Structure and Materials, Center for Supramolecular Chemical Biology, College of Chemistry, Jilin University, Changchun, 130012, China
| | - Danlan Fang
- Joint Laboratory of Opto-Functional Theranostics in Medicine and Chemistry, First Hospital of Jilin University, Changchun, 130021, China
- State Key Laboratory of Supramolecular Structure and Materials, Center for Supramolecular Chemical Biology, College of Chemistry, Jilin University, Changchun, 130012, China
| | - Wenzhong Li
- Joint Laboratory of Opto-Functional Theranostics in Medicine and Chemistry, First Hospital of Jilin University, Changchun, 130021, China
| | - Mengfei Li
- Joint Laboratory of Opto-Functional Theranostics in Medicine and Chemistry, First Hospital of Jilin University, Changchun, 130021, China
| | - Shoujun Zhu
- Joint Laboratory of Opto-Functional Theranostics in Medicine and Chemistry, First Hospital of Jilin University, Changchun, 130021, China.
- State Key Laboratory of Supramolecular Structure and Materials, Center for Supramolecular Chemical Biology, College of Chemistry, Jilin University, Changchun, 130012, China.
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Delle C, Wang X, Giannetto M, Newbold E, Peng W, Gomolka RS, Ladrón-de-Guevara A, Cankar N, Schiøler Nielsen E, Kjaerby C, Weikop P, Mori Y, Nedergaard M. Transient but not chronic hyperglycemia accelerates ocular glymphatic transport. Fluids Barriers CNS 2024; 21:26. [PMID: 38475818 DOI: 10.1186/s12987-024-00524-w] [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: 12/17/2023] [Accepted: 02/20/2024] [Indexed: 03/14/2024] Open
Abstract
Glymphatic transport is vital for the physiological homeostasis of the retina and optic nerve. Pathological alterations of ocular glymphatic fluid transport and enlarged perivascular spaces have been described in glaucomatous mice. It remains to be established how diabetic retinopathy, which impairs vision in about 50% of diabetes patients, impacts ocular glymphatic fluid transport. Here, we examined ocular glymphatic transport in chronic hyperglycemic diabetic mice as well as in healthy mice experiencing a daily transient increase in blood glucose. Mice suffering from severe diabetes for two and four months, induced by streptozotocin, exhibited no alterations in ocular glymphatic fluid transport in the optic nerve compared to age-matched, non-diabetic controls. In contrast, transient increases in blood glucose induced by repeated daily glucose injections in healthy, awake, non-diabetic mice accelerated antero- and retrograde ocular glymphatic transport. Structural analysis showed enlarged perivascular spaces in the optic nerves of glucose-treated mice, which were absent in diabetic mice. Thus, transient repeated hyperglycemic events, but not constant hyperglycemia, ultimately enlarge perivascular spaces in the murine optic nerve. These findings indicate that fluid transport in the mouse eye is vulnerable to fluctuating glycemic levels rather than constant hyperglycemia, suggesting that poor glycemic control drives glymphatic malfunction and perivascular enlargement in the optic nerve.
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Affiliation(s)
- Christine Delle
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark
| | - Xiaowei Wang
- Center for Translational Neuromedicine, University of Rochester Medical School, Elmwood Avenue 601, 14642, Rochester, NY, USA
- School of Medicine, University of California, San Francisco, 10 Koret Way, 94117, San Francisco, CA, USA
| | - Michael Giannetto
- Center for Translational Neuromedicine, University of Rochester Medical School, Elmwood Avenue 601, 14642, Rochester, NY, USA
| | - Evan Newbold
- Center for Translational Neuromedicine, University of Rochester Medical School, Elmwood Avenue 601, 14642, Rochester, NY, USA
| | - Weiguo Peng
- Center for Translational Neuromedicine, University of Rochester Medical School, Elmwood Avenue 601, 14642, Rochester, NY, USA
| | - Ryszard Stefan Gomolka
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark
| | - Antonio Ladrón-de-Guevara
- Center for Translational Neuromedicine, University of Rochester Medical School, Elmwood Avenue 601, 14642, Rochester, NY, USA
| | - Neža Cankar
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark
| | - Elise Schiøler Nielsen
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark
| | - Celia Kjaerby
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark
| | - Pia Weikop
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark
| | - Yuki Mori
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Faculty of Medical and Health Sciences, University of Copenhagen, Blegdamsvej 3B, 2200, Copenhagen N, Denmark.
- Center for Translational Neuromedicine, University of Rochester Medical School, Elmwood Avenue 601, 14642, Rochester, NY, USA.
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6
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Peng T, Xie Y, Liu F, Lian Y, Xie Y, Ma Y, Wang C, Xie N. The cerebral lymphatic drainage system and its implications in epilepsy. J Neurosci Res 2024; 102:e25267. [PMID: 38284855 DOI: 10.1002/jnr.25267] [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: 07/08/2023] [Revised: 09/18/2023] [Accepted: 10/08/2023] [Indexed: 01/30/2024]
Abstract
The central nervous system has long been thought to lack a clearance system similar to the peripheral lymphatic system. Therefore, the clearance of metabolic waste in the central nervous system has been a subject of great interest in neuroscience. Recently, the cerebral lymphatic drainage system, including the parenchymal clearance system and the meningeal lymphatic network, has attracted considerable attention. It has been extensively studied in various neurological disorders. Solute accumulation and neuroinflammation after epilepsy impair the blood-brain barrier, affecting the exchange and clearance between cerebrospinal fluid and interstitial fluid. Restoring their normal function may improve the prognosis of epilepsy. However, few studies have focused on providing a comprehensive overview of the brain clearance system and its significance in epilepsy. Therefore, this review addressed the structural composition, functions, and methods used to assess the cerebral lymphatic system, as well as the neglected association with epilepsy, and provided a theoretical basis for therapeutic approaches in epilepsy.
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Affiliation(s)
- Tingting Peng
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, P.R. China
- Academy of Medical Sciences of Zhengzhou University, Zhengzhou, P.R. China
| | - Yinyin Xie
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, P.R. China
- Academy of Medical Sciences of Zhengzhou University, Zhengzhou, P.R. China
| | - Fengxia Liu
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, P.R. China
| | - Yajun Lian
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, P.R. China
| | - Yi Xie
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, P.R. China
| | - Yunqing Ma
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, P.R. China
| | - Cui Wang
- Key Clinical Laboratory of Henan Province, Department of Clinical Laboratory, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, P.R. China
| | - Nanchang Xie
- Department of Neurology, The First Affiliated Hospital of Zhengzhou University, Zhengzhou, P.R. China
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7
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Plá V, Bitsika S, Giannetto MJ, Ladron-de-Guevara A, Gahn-Martinez D, Mori Y, Nedergaard M, Møllgård K. Structural characterization of SLYM-a 4th meningeal membrane. Fluids Barriers CNS 2023; 20:93. [PMID: 38098084 PMCID: PMC10722698 DOI: 10.1186/s12987-023-00500-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2023] [Accepted: 12/06/2023] [Indexed: 12/17/2023] Open
Abstract
Traditionally, the meninges are described as 3 distinct layers, dura, arachnoid and pia. Yet, the classification of the connective meningeal membranes surrounding the brain is based on postmortem macroscopic examination. Ultrastructural and single cell transcriptome analyses have documented that the 3 meningeal layers can be subdivided into several distinct layers based on cellular characteristics. We here re-examined the existence of a 4th meningeal membrane, Subarachnoid Lymphatic-like Membrane or SLYM in Prox1-eGFP reporter mice. Imaging of freshly resected whole brains showed that SLYM covers the entire brain and brain stem and forms a roof shielding the subarachnoid cerebrospinal fluid (CSF)-filled cisterns and the pia-adjacent vasculature. Thus, SLYM is strategically positioned to facilitate periarterial influx of freshly produced CSF and thereby support unidirectional glymphatic CSF transport. Histological analysis showed that, in spinal cord and parts of dorsal cortex, SLYM fused with the arachnoid barrier layer, while in the basal brain stem typically formed a 1-3 cell layered membrane subdividing the subarachnoid space into two compartments. However, great care should be taken when interpreting the organization of the delicate leptomeningeal membranes in tissue sections. We show that hyperosmotic fixatives dehydrate the tissue with the risk of shrinkage and dislocation of these fragile membranes in postmortem preparations.
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Affiliation(s)
- Virginia Plá
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Styliani Bitsika
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Michael J Giannetto
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Antonio Ladron-de-Guevara
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Daniel Gahn-Martinez
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Yuki Mori
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200, Denmark
| | - Maiken Nedergaard
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200, Denmark.
- Division of Glial Disease and Therapeutics, Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, NY, 14642, USA.
| | - Kjeld Møllgård
- Department of Cellular and Molecular Medicine, Faculty of Health and Medical Sciences, University of Copenhagen, Copenhagen, 2200, Denmark.
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8
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Plá V, Bitsika S, Giannetto M, Ladron-de-Guevara A, Gahn-Martinez D, Mori Y, Nedergaard M, Møllgård K. Structural characterization of SLYM - a 4th meningeal membrane. RESEARCH SQUARE 2023:rs.3.rs-3500436. [PMID: 37961391 PMCID: PMC10635397 DOI: 10.21203/rs.3.rs-3500436/v1] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Traditionally, the meninges are described as 3 distinct layers, dura, arachnoid and pia. Yet, the classification of the connective meningeal membranes surrounding the brain is based on postmortem macroscopic examination. Ultrastructural and single cell transcriptome analyses have documented that the 3 meningeal layers can be subdivided into several distinct layers based on cellular characteristics. We here re-examined the existence of a 4th meningeal membrane, Subarachnoid Lymphatic-like Membrane or SLYM in Prox1-eGFP reporter mice. Imaging of freshly resected whole brains showed that SLYM covers the entire brain and brain stem and forms a roof shielding the subarachnoid cerebrospinal fluid (CSF)-filled cisterns and the pia-adjacent vasculature. Thus, SLYM is strategically positioned to facilitate periarterial influx of freshly produced CSF and thereby support unidirectional glymphatic CSF transport. Histological analysis showed that, in spinal cord and parts of dorsal cortex, SLYM fused with the arachnoid barrier layer, while in the basal brain stem typically formed a 1-3 cell layered membrane subdividing the subarachnoid space into two compartments. However, great care should be taken when interpreting the organization of the delicate leptomeningeal membranes in tissue sections. We show that hyperosmotic fixatives dehydrate the tissue with the risk of shrinkage and dislocation of these fragile membranes in postmortem preparations.
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9
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Plá V, Bitsika S, Giannetto M, Ladron-de-Guevara A, Gahn-Martinez D, Mori Y, Nedergaard M, Møllgård K. Structural characterization of SLYM - a 4 th meningeal membrane. BIORXIV : THE PREPRINT SERVER FOR BIOLOGY 2023:2023.10.20.563351. [PMID: 37961461 PMCID: PMC10634706 DOI: 10.1101/2023.10.20.563351] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/15/2023]
Abstract
Traditionally, the meninges are described as 3 distinct layers, dura, arachnoid and pia. Yet, the classification of the connective meningeal membranes surrounding the brain is based on postmortem macroscopic examination. Ultrastructural and single cell transcriptome analyses have documented that the 3 meningeal layers can be subdivided into several distinct layers based on cellular characteristics. We here re-examined the existence of a 4 th meningeal membrane, S ubarachnoid Ly mphatic-like M embrane or SLYM in Prox1-eGFP reporter mice. Imaging of freshly resected whole brains showed that SLYM covers the entire brain and brain stem and forms a roof shielding the subarachnoid cerebrospinal fluid (CSF)-filled cisterns and the pia-adjacent vasculature. Thus, SLYM is strategically positioned to facilitate periarterial influx of freshly produced CSF and thereby support unidirectional glymphatic CSF transport. Histological analysis showed that, in spinal cord and parts of dorsal cortex, SLYM fused with the arachnoid barrier layer, while in the basal brain stem typically formed a 1-3 cell layered membrane subdividing the subarachnoid space into two compartments. However, great care should be taken when interpreting the organization of the delicate leptomeningeal membranes in tissue sections. We show that hyperosmotic fixatives dehydrate the tissue with the risk of shrinkage and dislocation of these fragile membranes in postmortem preparations.
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10
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Miyakoshi LM, Stæger FF, Li Q, Pan C, Xie L, Kang H, Pavan C, Dang J, Sun Q, Ertürk A, Nedergaard M. The state of brain activity modulates cerebrospinal fluid transport. Prog Neurobiol 2023; 229:102512. [PMID: 37482196 DOI: 10.1016/j.pneurobio.2023.102512] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2023] [Revised: 06/13/2023] [Accepted: 07/18/2023] [Indexed: 07/25/2023]
Abstract
Earlier studies based on 2-photon imaging have shown that glymphatic cerebrospinal fluid (CSF) transport is regulated by the sleep-wake cycle. To examine this association, we used 3DISCO whole-body tissue clearing to map CSF tracer distribution in awake, sleeping and ketamine-xylazine anesthetized mice. The results of our analysis showed that CSF tracers entered the brain to a significantly larger extent in natural sleep or ketamine-xylazine anesthesia than in wakefulness. Furthermore, awake mice showed preferential transport of CSF tracers in the rostro-caudal direction towards the cervical and spinal cord lymphatic vessels, and hence to venous circulation and excretion by the kidneys. The study extends the current literature by showing that CSF dynamics on the whole-body scale is controlled by the state of brain activity.
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Affiliation(s)
- Leo M Miyakoshi
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics University of Copenhagen, 2200, Denmark
| | - Frederik F Stæger
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics University of Copenhagen, 2200, Denmark
| | - Qianliang Li
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics University of Copenhagen, 2200, Denmark
| | - Chenchen Pan
- Institute for Tissue Engineering and Regenerative Medicine (iTERM), Helmholtz Center Munich, Neuherberg, Germany; Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig-Maximilians University Munich, Munich, Germany
| | - Lulu Xie
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Hongyi Kang
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Chiara Pavan
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics University of Copenhagen, 2200, Denmark
| | - Juliana Dang
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics University of Copenhagen, 2200, Denmark
| | - Qian Sun
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Ali Ertürk
- Institute for Tissue Engineering and Regenerative Medicine (iTERM), Helmholtz Center Munich, Neuherberg, Germany; Institute for Stroke and Dementia Research, Klinikum der Universität München, Ludwig-Maximilians University Munich, Munich, Germany
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics University of Copenhagen, 2200, Denmark; Center for Translational Neuromedicine, Division of Glial Disease and Therapeutics, University of Rochester Medical Center, Rochester, NY, 14642, USA.
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11
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Hoiland RL, Robba C, Menon DK, Citerio G, Sandroni C, Sekhon MS. Clinical targeting of the cerebral oxygen cascade to improve brain oxygenation in patients with hypoxic-ischaemic brain injury after cardiac arrest. Intensive Care Med 2023; 49:1062-1078. [PMID: 37507572 PMCID: PMC10499700 DOI: 10.1007/s00134-023-07165-x] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/13/2023] [Accepted: 07/07/2023] [Indexed: 07/30/2023]
Abstract
The cerebral oxygen cascade includes three key stages: (a) convective oxygen delivery representing the bulk flow of oxygen to the cerebral vascular bed; (b) diffusion of oxygen from the blood into brain tissue; and (c) cellular utilisation of oxygen for aerobic metabolism. All three stages may become dysfunctional after resuscitation from cardiac arrest and contribute to hypoxic-ischaemic brain injury (HIBI). Improving convective cerebral oxygen delivery by optimising cerebral blood flow has been widely investigated as a strategy to mitigate HIBI. However, clinical trials aimed at optimising convective oxygen delivery have yielded neutral results. Advances in the understanding of HIBI pathophysiology suggest that impairments in the stages of the oxygen cascade pertaining to oxygen diffusion and cellular utilisation of oxygen should also be considered in identifying therapeutic strategies for the clinical management of HIBI patients. Culprit mechanisms for these impairments may include a widening of the diffusion barrier due to peri-vascular oedema and mitochondrial dysfunction. An integrated approach encompassing both intra-parenchymal and non-invasive neuromonitoring techniques may aid in detecting pathophysiologic changes in the oxygen cascade and enable patient-specific management aimed at reducing the severity of HIBI.
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Affiliation(s)
- Ryan L Hoiland
- Division of Critical Care Medicine, Department of Medicine, Faculty of Medicine, Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada.
- Division of Neurosurgery, Department of Surgery, Faculty of Medicine, University of British Columbia, Vancouver, BC, Canada.
- Centre for Heart, Lung, and Vascular Health, School of Health and Exercise Sciences, Faculty of Health and Social Development, University of British Columbia Okanagan, Kelowna, BC, Canada.
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada.
- Collaborative Entity for REsearching Brain Ischemia (CEREBRI), University of British Columbia, Vancouver, BC, Canada.
| | - Chiara Robba
- Anesthesia and Intensive Care, San Martino Policlinico Hospital, IRCCS for Oncology and Neurosciences, Genoa, Italy
- Department of Surgical Sciences and Integrated Diagnostics, University of Genoa, Genoa, Italy
| | - David K Menon
- Department of Medicine, University Division of Anaesthesia, University of Cambridge, Cambridge, UK
| | - Giuseppe Citerio
- School of Medicine and Surgery, University of Milan-Bicocca, Monza, Italy
| | - Claudio Sandroni
- Department of Intensive Care, Emergency Medicine and Anaesthesiology, Fondazione Policlinico Universitario "Agostino Gemelli", IRCCS, Università Cattolica del Sacro Cuore, Rome, Italy
| | - Mypinder S Sekhon
- Division of Critical Care Medicine, Department of Medicine, Faculty of Medicine, Vancouver General Hospital, University of British Columbia, Vancouver, BC, Canada
- International Collaboration on Repair Discoveries, University of British Columbia, Vancouver, BC, Canada
- Collaborative Entity for REsearching Brain Ischemia (CEREBRI), University of British Columbia, Vancouver, BC, Canada
- Djavad Mowafaghian Centre for Brain Health, University of British Columbia, Vancouver, BC, Canada
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12
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Exton J, Higgins JMG, Chen J. Acute brain slice elastic modulus decreases over time. Sci Rep 2023; 13:12826. [PMID: 37550376 PMCID: PMC10406937 DOI: 10.1038/s41598-023-40074-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2023] [Accepted: 08/04/2023] [Indexed: 08/09/2023] Open
Abstract
A common benchmark in the brain tissue mechanics literature is that the properties of acute brain slices should be measured within 8 h of the experimental animal being sacrificed. The core assumption is that-since there is no substantial protein degradation during this time-there will be no change to elastic modulus. This assumption overlooks the possibility of other effects (such as osmotic swelling) that may influence the mechanical properties of the tissue. To achieve consistent and accurate analysis of brain mechanics, it is important to account for or mitigate these effects. Using atomic force microscopy (AFM), tissue hydration and volume measurements, we find that acute brain slices in oxygenated artificial cerebrospinal fluid (aCSF) with a standard osmolarity of 300 mOsm/l experience rapid swelling, softening, and increases in hydration within the first 2 hours after slicing. Reductions in elastic modulus can be partly mitigated by addition of chondroitinase ABC enzyme (CHABC). Increasing aCSF osmolarity to 400 mOsm/l does not prevent softening but may hasten equilibration of samples to a point where measurements of relative elastic modulus are consistent across experiments.
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Affiliation(s)
- John Exton
- School of Engineering, Newcastle University, Newcastle Upon Tyne, NE1 7RU, UK
| | - Jonathan M G Higgins
- Biosciences Institute, Faculty of Medical Sciences, Newcastle University, Framlington Place, Newcastle Upon Tyne, NE2 4HH, UK
| | - Jinju Chen
- School of Engineering, Newcastle University, Newcastle Upon Tyne, NE1 7RU, UK.
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13
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Mukherjee S, Mirzaee M, Tithof J. Quantifying the relationship between spreading depolarization and perivascular cerebrospinal fluid flow. Sci Rep 2023; 13:12405. [PMID: 37524734 PMCID: PMC10390554 DOI: 10.1038/s41598-023-38938-5] [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: 05/15/2023] [Accepted: 07/17/2023] [Indexed: 08/02/2023] Open
Abstract
Recent studies have linked spreading depolarization (SD, an electro-chemical wave in the brain following stroke, migraine, traumatic brain injury, and more) with increase in cerebrospinal fluid (CSF) flow through the perivascular spaces (PVSs, annular channels lining the brain vasculature). We develop a novel computational model that couples SD and CSF flow. We first use high order numerical simulations to solve a system of physiologically realistic reaction-diffusion equations which govern the spatiotemporal dynamics of ions in the extracellular and intracellular spaces of the brain cortex during SD. We then couple the SD wave with a 1D CSF flow model that captures the change in cross-sectional area, pressure, and volume flow rate through the PVSs. The coupling is modelled using an empirical relationship between the excess potassium ion concentration in the extracellular space following SD and the vessel radius. We find that the CSF volumetric flow rate depends intricately on the length and width of the PVS, as well as the vessel radius and the angle of incidence of the SD wave. We derive analytical expressions for pressure and volumetric flow rates of CSF through the PVS for a given SD wave and quantify CSF flow variations when two SD waves collide. Our numerical approach is very general and could be extended in the future to obtain novel, quantitative insights into how CSF flow in the brain couples with slow waves, functional hyperemia, seizures, or externally applied neural stimulations.
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Affiliation(s)
- Saikat Mukherjee
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN, 55455, USA.
- Department of Mechanical Engineering, Iowa State University, Ames, IA, 50011, USA.
| | - Mahsa Mirzaee
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
| | - Jeffrey Tithof
- Department of Mechanical Engineering, University of Minnesota, Minneapolis, MN, 55455, USA
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14
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Sigurdsson B, Hauglund NL, Lilius TO, Mogensen FLH, Mortensen KN, Beschorner N, Klinger L, Bærentzen SL, Rosenholm MP, Shalgunov V, Herth M, Mori Y, Nedergaard M. A SPECT-based method for dynamic imaging of the glymphatic system in rats. J Cereb Blood Flow Metab 2023; 43:1153-1165. [PMID: 36809165 PMCID: PMC10291457 DOI: 10.1177/0271678x231156982] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/10/2022] [Revised: 11/17/2022] [Accepted: 12/07/2022] [Indexed: 02/23/2023]
Abstract
The glymphatic system is a brain-wide waste drainage system that promotes cerebrospinal fluid circulation through the brain to remove waste metabolites. Currently, the most common methods for assessing glymphatic function are ex vivo fluorescence microscopy of brain slices, macroscopic cortical imaging, and MRI. While all these methods have been crucial for expanding our understanding of the glymphatic system, new techniques are required to overcome their specific drawbacks. Here, we evaluate SPECT/CT imaging as a tool to assess glymphatic function in different anesthesia-induced brain states using two radiolabeled tracers, [111In]-DTPA and [99mTc]-NanoScan. Using SPECT, we confirmed the existence of brain state-dependent differences in glymphatic flow and we show brain state-dependent differences of CSF flow kinetics and CSF egress to the lymph nodes. We compare SPECT and MRI for imaging glymphatic flow and find that the two imaging modalities show the same overall pattern of CSF flow, but that SPECT was specific across a greater range of tracer concentrations than MRI. Overall, we find that SPECT imaging is a promising tool for imaging the glymphatic system, and that qualities such as high sensitivity and the variety of available tracers make SPECT imaging a good alternative for glymphatic research.
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Affiliation(s)
- Björn Sigurdsson
- Center for Translational Neuromedicine, University of Copenhagen, Denmark
| | - Natalie L Hauglund
- Center for Translational Neuromedicine, University of Copenhagen, Denmark
| | - Tuomas O Lilius
- Center for Translational Neuromedicine, University of Copenhagen, Denmark
- INDIVIDRUG Research Program, University of Helsinki, Finland
- Department of Pharmacology, University of Helsinki, Finland
- Department of Emergency Medicine and Services, Helsinki University Hospital and University of Helsinki, Finland
| | - Frida L-H Mogensen
- Center for Translational Neuromedicine, University of Copenhagen, Denmark
- Neuro-Immunology Group, Department of Cancer Research, Luxembourg Institute of Health, Luxembourg, Luxembourg
- Doctoral School of Science and Technology, University of Luxembourg, Esch-sur-Alzette, Luxembourg
| | | | - Natalie Beschorner
- Center for Translational Neuromedicine, University of Copenhagen, Denmark
| | - Laura Klinger
- Center for Translational Neuromedicine, University of Copenhagen, Denmark
| | - Simone L Bærentzen
- Translational Neuropsychiatry Unit, Department of Clinical Medicine, Aarhus University, Aarhus, Denmark
- Department of Nuclear Medicine and PET Center, Aarhus University Hospital, Aarhus, Denmark
| | - Marko P Rosenholm
- Center for Translational Neuromedicine, University of Copenhagen, Denmark
| | - Vladimir Shalgunov
- Department of Drug Design and Pharmacology, University of Copenhagen, Denmark
| | - Matthias Herth
- Department of Drug Design and Pharmacology, University of Copenhagen, Denmark
- Department of Clinical Physiology, Copenhagen University Hospital, Denmark
| | - Yuki Mori
- Center for Translational Neuromedicine, University of Copenhagen, Denmark
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Copenhagen, Denmark
- Center for Translational Neuromedicine, University of Rochester Medical Center, USA
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15
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Rey JA, Farid UM, Najjoum CM, Brown A, Magdoom KN, Mareci TH, Sarntinoranont M. Perivascular network segmentations derived from high-field MRI and their implications for perivascular and parenchymal mass transport in the rat brain. Sci Rep 2023; 13:9205. [PMID: 37280246 DOI: 10.1038/s41598-023-34850-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/31/2022] [Accepted: 05/09/2023] [Indexed: 06/08/2023] Open
Abstract
A custom segmentation workflow was applied to ex vivo high-field MR images of rat brains acquired following in vivo intraventricular contrast agent infusion to generate maps of the perivascular spaces (PVS). The resulting perivascular network segmentations enabled analysis of perivascular connections to the ventricles, parenchymal solute clearance, and dispersive solute transport within PVS. Numerous perivascular connections between the brain surface and the ventricles suggest the ventricles integrate into a PVS-mediated clearance system and raise the possibility of cerebrospinal fluid (CSF) return from the subarachnoid space to the ventricles via PVS. Assuming rapid solute exchange between the PVS and CSF spaces primarily by advection, the extensive perivascular network decreased the mean clearance distance from parenchyma to the nearest CSF compartment resulting in an over 21-fold reduction in the estimated diffusive clearance time scale, irrespective of solute diffusivity. This corresponds to an estimated diffusive clearance time scale under 10 min for amyloid-beta which suggests that the widespread distribution of PVS may render diffusion an effective parenchymal clearance mechanism. Additional analysis of oscillatory solute dispersion within PVS indicates that advection rather than dispersion is likely the primary transport mechanism for dissolved compounds greater than 66 kDa in the long (> 2 mm) perivascular segments identified here, although dispersion may be significant for smaller compounds in shorter perivascular segments.
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Affiliation(s)
- Julian A Rey
- Department of Mechanical and Aerospace Engineering, University of Florida, PO BOX 116250, Gainesville, FL, 32611, USA
| | - Uzair M Farid
- Department of Mechanical and Aerospace Engineering, University of Florida, PO BOX 116250, Gainesville, FL, 32611, USA
| | - Christopher M Najjoum
- Department of Mechanical and Aerospace Engineering, University of Florida, PO BOX 116250, Gainesville, FL, 32611, USA
| | - Alec Brown
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, USA
| | - Kulam Najmudeen Magdoom
- Department of Mechanical and Aerospace Engineering, University of Florida, PO BOX 116250, Gainesville, FL, 32611, USA
| | - Thomas H Mareci
- Department of Biochemistry and Molecular Biology, University of Florida, Gainesville, FL, USA
| | - Malisa Sarntinoranont
- Department of Mechanical and Aerospace Engineering, University of Florida, PO BOX 116250, Gainesville, FL, 32611, USA.
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16
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Coppler PJ, Elmer J, Doshi A, Guyette FX, Okubo M, Ratay C, Frisch AN, Steinberg A, Weissman A, Arias V, Drumheller BC, Flickinger KL, Faro J, Schmidhofer M, Rhinehart ZJ, Hansra BS, Fong-Isariyawongse J, Barot N, Baldwin ME, Murat Kaynar A, Darby JM, Shutter LA, Mettenburg J, Callaway CW. Duration of cardiopulmonary resuscitation and phenotype of post-cardiac arrest brain injury. Resuscitation 2023; 188:109823. [PMID: 37164175 DOI: 10.1016/j.resuscitation.2023.109823] [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: 02/24/2023] [Revised: 04/17/2023] [Accepted: 05/01/2023] [Indexed: 05/12/2023]
Abstract
BACKGROUND Patients resuscitated from cardiac arrest have variable severity of primary hypoxic ischemic brain injury (HIBI). Signatures of primary HIBI on brain imaging and electroencephalography (EEG) include diffuse cerebral edema and burst suppression with identical bursts (BSIB). We hypothesize distinct phenotypes of primary HIBI are associated with increasing cardiopulmonary resuscitation (CPR) duration. METHODS We identified from our prospective registry of both in-and out-of-hospital CA patients treated between January 2010 to January 2020 for this cohort study. We abstracted CPR duration, neurological examination, initial brain computed tomography gray to white ratio (GWR), and initial EEG pattern. We considered four phenotypes on presentation: awake; comatose with neither BSIB nor cerebral edema (non-malignant coma); BSIB; and cerebral edema (GWR ≤ 1.20). BSIB and cerebral edema were considered as non-mutually exclusive outcomes. We generated predicted probabilities of brain injury phenotype using localized regression. RESULTS We included 2,440 patients, of whom 545 (23%) were awake, 1,065 (44%) had non-malignant coma, 548 (23%) had BSIB and 438 (18%) had cerebral edema. Only 92 (4%) had both BSIB and edema. Median CPR duration was 16 [IQR 8-28] minutes. Median CPR duration increased in a stepwise manner across groups: awake 6 [3-13] minutes; non-malignant coma 15 [8-25] minutes; BSIB 21 [13-31] minutes; cerebral edema 32 [22-46] minutes. Predicted probability of phenotype changes over time. CONCLUSIONS Brain injury phenotype is related to CPR duration, which is a surrogate for severity of HIBI. The sequence of most likely primary HIBI phenotype with progressively longer CPR duration is awake, coma without BSIB or edema, BSIB, and finally cerebral edema.
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Affiliation(s)
- Patrick J Coppler
- Department of Emergency Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jonathan Elmer
- Department of Emergency Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Ankur Doshi
- Department of Emergency Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Francis X Guyette
- Department of Emergency Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Masashi Okubo
- Department of Emergency Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Cecelia Ratay
- Department of Emergency Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Adam N Frisch
- Department of Emergency Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Alexis Steinberg
- Department of Emergency Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Alexandra Weissman
- Department of Emergency Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Valerie Arias
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Byron C Drumheller
- Department of Emergency Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - John Faro
- Department of Medicine, Soin Medical Center - Kettering Health, Beavercreek, OH, USA
| | - Mark Schmidhofer
- Department of Medicine, Division of Cardiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Zachary J Rhinehart
- Department of Emergency Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Barinder S Hansra
- Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Medicine, Division of Cardiology, University of Pittsburgh, Pittsburgh, PA, USA
| | | | - Niravkumar Barot
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Maria E Baldwin
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA
| | - A Murat Kaynar
- Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Anesthesiology and Perioperative Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Joseph M Darby
- Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Lori A Shutter
- Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA; Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Joseph Mettenburg
- Department of Radiology, University of Pittsburgh, Pittsburgh, PA, USA
| | - Clifton W Callaway
- Department of Emergency Medicine, University of Pittsburgh, Pittsburgh, PA, USA.
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17
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Keep RF, Jones HC, Hamilton MG, Drewes LR. A year in review: brain barriers and brain fluids research in 2022. Fluids Barriers CNS 2023; 20:30. [PMID: 37085841 PMCID: PMC10120509 DOI: 10.1186/s12987-023-00429-0] [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: 04/07/2023] [Indexed: 04/23/2023] Open
Abstract
This aim of this editorial is to highlight progress made in brain barrier and brain fluid research in 2022. It covers studies on the blood-brain, blood-retina and blood-CSF barriers (choroid plexus and meninges), signaling within the neurovascular unit and elements of the brain fluid systems. It further discusses how brain barriers and brain fluid systems are impacted in CNS diseases, their role in disease progression and progress being made in treating such diseases.
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Affiliation(s)
- Richard F Keep
- Department of Neurosurgery, University of Michigan, R5018 BSRB 109 Zina Pitcher Place, Ann Arbor, MI, 48109-2200, USA.
| | | | - Mark G Hamilton
- Department of Clinical Neurosciences, Division of Neurosurgery, University of Calgary, Alberta, Canada
| | - Lester R Drewes
- Department of Biomedical Sciences, University of Minnesota Medical School Duluth, Duluth, MN, 55812, USA
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18
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Maex R. An Isotonic Model of Neuron Swelling Based on Co-Transport of Salt and Water. MEMBRANES 2023; 13:206. [PMID: 36837709 PMCID: PMC9958824 DOI: 10.3390/membranes13020206] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Subscribe] [Scholar Register] [Received: 12/29/2022] [Revised: 01/31/2023] [Accepted: 02/06/2023] [Indexed: 06/18/2023]
Abstract
Neurons spend most of their energy building ion gradients across the cell membrane. During energy deprivation the neurons swell, and the concomitant mixing of their ions is commonly assumed to lead toward a Donnan equilibrium, at which the concentration gradients of all permeant ion species have the same Nernst potential. This Donnan equilibrium, however, is not isotonic, as the total concentration of solute will be greater inside than outside the neurons. The present theoretical paper, in contrast, proposes that neurons follow a path along which they swell quasi-isotonically by co-transporting water and ions. The final neuronal volume on the path is taken that at which the concentration of impermeant anions in the shrinking extracellular space equals that inside the swelling neurons. At this final state, which is also a Donnan equilibrium, all permeant ions can mix completely, and their Nernst potentials vanish. This final state is isotonic and electro-neutral, as are all intermediate states along this path. The path is in principle reversible, and maximizes the work of mixing.
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Affiliation(s)
- Reinoud Maex
- Biocomputation Research Group, School of Physics, Engineering and Computer Science, University of Hertfordshire, College Lane, Hatfield AL10 9AB, UK
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19
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Yan JH, Wang YJ, Sun YR, Pei YH, Ma HW, Mu YK, Qin LH. The lymphatic drainage systems in the brain: a novel target for ischemic stroke? Neural Regen Res 2023; 18:485-491. [DOI: 10.4103/1673-5374.346484] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/04/2022] Open
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20
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Liu G, Ladrón-de-Guevara A, Izhiman Y, Nedergaard M, Du T. Measurements of cerebrospinal fluid production: a review of the limitations and advantages of current methodologies. Fluids Barriers CNS 2022; 19:101. [PMID: 36522656 PMCID: PMC9753305 DOI: 10.1186/s12987-022-00382-4] [Citation(s) in RCA: 13] [Impact Index Per Article: 6.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/25/2022] [Accepted: 10/13/2022] [Indexed: 12/23/2022] Open
Abstract
Cerebrospinal fluid (CSF) is an essential and critical component of the central nervous system (CNS). According to the concept of the "third circulation" originally proposed by Cushing, CSF is mainly produced by the choroid plexus and subsequently leaves the cerebral ventricles via the foramen of Magendie and Luschka. CSF then fills the subarachnoid space from whence it disperses to all parts of the CNS, including the forebrain and spinal cord. CSF provides buoyancy to the submerged brain, thus protecting it against mechanical injury. CSF is also transported via the glymphatic pathway to reach deep interstitial brain regions along perivascular channels; this CSF clearance pathway promotes transport of energy metabolites and signaling molecules, and the clearance of metabolic waste. In particular, CSF is now intensively studied as a carrier for the removal of proteins implicated in neurodegeneration, such as amyloid-β and tau. Despite this key function of CSF, there is little information about its production rate, the factors controlling CSF production, and the impact of diseases on CSF flux. Therefore, we consider it to be a matter of paramount importance to quantify better the rate of CSF production, thereby obtaining a better understanding of CSF dynamics. To this end, we now review the existing methods developed to measure CSF production, including invasive, noninvasive, direct, and indirect methods, and MRI-based techniques. Depending on the methodology, estimates of CSF production rates in a given species can extend over a ten-fold range. Throughout this review, we interrogate the technical details of CSF measurement methods and discuss the consequences of minor experimental modifications on estimates of production rate. Our aim is to highlight the gaps in our knowledge and inspire the development of more accurate, reproducible, and less invasive techniques for quantitation of CSF production.
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Affiliation(s)
- Guojun Liu
- Department of Neurosurgery, The Fourth Affiliated Hospital of China Medical University, Shenyang, 110032, China
- School of Pharmacy, China Medical University, Shenyang, 110122, China
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark
- Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Antonio Ladrón-de-Guevara
- Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Yara Izhiman
- Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, 14642, USA
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark.
- Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, 14642, USA.
| | - Ting Du
- School of Pharmacy, China Medical University, Shenyang, 110122, China.
- Center for Translational Neuromedicine, Faculty of Health and Medical Sciences, University of Copenhagen, 2200, Copenhagen, Denmark.
- Center for Translational Neuromedicine, Department of Neurosurgery, University of Rochester Medical Center, Rochester, NY, 14642, USA.
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21
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Abstract
We review theoretical and numerical models of the glymphatic system, which circulates cerebrospinal fluid and interstitial fluid around the brain, facilitating solute transport. Models enable hypothesis development and predictions of transport, with clinical applications including drug delivery, stroke, cardiac arrest, and neurodegenerative disorders like Alzheimer’s disease. We sort existing models into broad categories by anatomical function: Perivascular flow, transport in brain parenchyma, interfaces to perivascular spaces, efflux routes, and links to neuronal activity. Needs and opportunities for future work are highlighted wherever possible; new models, expanded models, and novel experiments to inform models could all have tremendous value for advancing the field.
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22
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Coppler PJ, Elmer J. Optimizing cerebral oxygen delivery after cardiac arrest: A role for neuromonitoring. Resuscitation 2021; 169:220-222. [PMID: 34748767 DOI: 10.1016/j.resuscitation.2021.10.043] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/27/2021] [Accepted: 10/29/2021] [Indexed: 10/19/2022]
Affiliation(s)
- Patrick J Coppler
- Department of Emergency Medicine, University of Pittsburgh, Pittsburgh, PA, USA
| | - Jonathan Elmer
- Department of Emergency Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Critical Care Medicine, University of Pittsburgh, Pittsburgh, PA, USA; Department of Neurology, University of Pittsburgh, Pittsburgh, PA, USA.
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