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Das N, Dhamija R, Sarkar S. The role of astrocytes in the glymphatic network: a narrative review. Metab Brain Dis 2024; 39:453-465. [PMID: 38008886 DOI: 10.1007/s11011-023-01327-y] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Accepted: 11/17/2023] [Indexed: 11/28/2023]
Abstract
To date, treatment of Central Nervous System (CNS) pathology has largely focused on neuronal structure and function. Yet, revived attention towards fluid circulation within the CNS has exposed the need to further explore the role of glial cells in maintaining homeostasis within neural networks. In the past decade, discovery of the neural glymphatic network has revolutionized traditional understanding of fluid dynamics within the CNS. Advancements in neuroimaging have revealed alternative pathways of cerebrospinal fluid (CSF) generation and efflux. Here, we discuss emerging perspectives on the role of astrocytes in CSF hydrodynamics, with particular focus on the contribution of aquaporin-4 channels to the glymphatic network. Astrocytic structural features and expression patterns are detailed in relation to their function in maintaining integrity of the Blood Brain Barrier (BBB) as part of the neurovascular unit (NVU). This narrative also highlights the potential role of glial dysfunction in pathogenesis of neurodegenerative disease, hydrocephalus, intracranial hemorrhage, ischemic stroke, and traumatic brain injury. The purpose of this literature summary is to provide an update on the changing landscape of scientific theory surrounding production, flow, and absorption of cerebrospinal fluid. The overarching aim of this narrative review is to advance the conception of basic, translational, and clinical research endeavors investigating glia as therapeutic targets for neurological disease.
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Affiliation(s)
- Nikita Das
- Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Ravi Dhamija
- Case Western Reserve University School of Medicine, Cleveland, OH, USA
| | - Sumit Sarkar
- Division of Neurotoxicology, HFT-132, National Center for Toxicological Research, U.S. Food & Drug Administration, Jefferson, AR, 72079, USA.
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2
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Boyd ED, Zhang L, Ding G, Li L, Lu M, Li Q, Huang R, Kaur J, Hu J, Chopp M, Zhang Z, Jiang Q. The Glymphatic Response to the Development of Type 2 Diabetes. Biomedicines 2024; 12:401. [PMID: 38398003 PMCID: PMC10886551 DOI: 10.3390/biomedicines12020401] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Revised: 01/21/2024] [Accepted: 02/02/2024] [Indexed: 02/25/2024] Open
Abstract
The glymphatic system has recently been shown to be important in neurological diseases, including diabetes. However, little is known about how the progressive onset of diabetes affects the glymphatic system. The aim of this study is to investigate the glymphatic system response to the progressive onset of diabetes in a rat model of type 2 diabetic mellitus. Male Wistar rats (n = 45) with and without diabetes were evaluated using MRI glymphatic tracer kinetics, functional tests, and brain tissue immunohistochemistry. Our data demonstrated that the contrast agent clearance impairment gradually progressed with the diabetic duration. The MRI data showed that an impairment in contrast clearance occurred prior to the cognitive deficits detected using functional tests and permitted the detection of an early DM stage compared to the immuno-histopathology and cognitive tests. Additionally, the quantitative MRI markers of brain waste clearance demonstrated region-dependent sensitivity in glymphatic impairment. The improved sensitivity of MRI markers in the olfactory bulb and the whole brain at an early DM stage may be attributed to the important role of the olfactory bulb in the parenchymal efflux pathway. MRI can provide sensitive quantitative markers of glymphatic impairment during the progression of DM and can be used as a valuable tool for the early diagnosis of DM with a potential for clinical application.
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Affiliation(s)
- Edward D. Boyd
- Department of Neurology, Henry Ford Health System, E&R B126, 2799 West Grand Boulevard, Detroit, MI 48202, USA; (L.Z.); (G.D.); (L.L.); (Q.L.); (J.K.); (M.C.); (Z.Z.); (Q.J.)
- Department of Radiology, Michigan State University, East Lansing, MI 48824, USA
| | - Li Zhang
- Department of Neurology, Henry Ford Health System, E&R B126, 2799 West Grand Boulevard, Detroit, MI 48202, USA; (L.Z.); (G.D.); (L.L.); (Q.L.); (J.K.); (M.C.); (Z.Z.); (Q.J.)
| | - Guangliang Ding
- Department of Neurology, Henry Ford Health System, E&R B126, 2799 West Grand Boulevard, Detroit, MI 48202, USA; (L.Z.); (G.D.); (L.L.); (Q.L.); (J.K.); (M.C.); (Z.Z.); (Q.J.)
- Department of Radiology, Michigan State University, East Lansing, MI 48824, USA
| | - Lian Li
- Department of Neurology, Henry Ford Health System, E&R B126, 2799 West Grand Boulevard, Detroit, MI 48202, USA; (L.Z.); (G.D.); (L.L.); (Q.L.); (J.K.); (M.C.); (Z.Z.); (Q.J.)
| | - Mei Lu
- Department of Public Health Sciences, Henry Ford Health System, Detroit, MI 48202, USA;
| | - Qingjiang Li
- Department of Neurology, Henry Ford Health System, E&R B126, 2799 West Grand Boulevard, Detroit, MI 48202, USA; (L.Z.); (G.D.); (L.L.); (Q.L.); (J.K.); (M.C.); (Z.Z.); (Q.J.)
| | - Rui Huang
- Department of Neurology, Henry Ford Health System, E&R B126, 2799 West Grand Boulevard, Detroit, MI 48202, USA; (L.Z.); (G.D.); (L.L.); (Q.L.); (J.K.); (M.C.); (Z.Z.); (Q.J.)
| | - Jasleen Kaur
- Department of Neurology, Henry Ford Health System, E&R B126, 2799 West Grand Boulevard, Detroit, MI 48202, USA; (L.Z.); (G.D.); (L.L.); (Q.L.); (J.K.); (M.C.); (Z.Z.); (Q.J.)
- Department of Physics, Oakland University, Rochester, MI 48309, USA
| | - Jiani Hu
- Department of Radiology, Wayne State University, Detroit, MI 48202, USA;
| | - Michael Chopp
- Department of Neurology, Henry Ford Health System, E&R B126, 2799 West Grand Boulevard, Detroit, MI 48202, USA; (L.Z.); (G.D.); (L.L.); (Q.L.); (J.K.); (M.C.); (Z.Z.); (Q.J.)
- Department of Physics, Oakland University, Rochester, MI 48309, USA
- Department of Neurology, Wayne State University, Detroit, MI 28202, USA
| | - Zhenggang Zhang
- Department of Neurology, Henry Ford Health System, E&R B126, 2799 West Grand Boulevard, Detroit, MI 48202, USA; (L.Z.); (G.D.); (L.L.); (Q.L.); (J.K.); (M.C.); (Z.Z.); (Q.J.)
- Department of Neurology, Wayne State University, Detroit, MI 28202, USA
| | - Quan Jiang
- Department of Neurology, Henry Ford Health System, E&R B126, 2799 West Grand Boulevard, Detroit, MI 48202, USA; (L.Z.); (G.D.); (L.L.); (Q.L.); (J.K.); (M.C.); (Z.Z.); (Q.J.)
- Department of Radiology, Michigan State University, East Lansing, MI 48824, USA
- Department of Physics, Oakland University, Rochester, MI 48309, USA
- Department of Neurology, Wayne State University, Detroit, MI 28202, USA
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3
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Chae J, Choi M, Choi J, Yoo SJ. The nasal lymphatic route of CSF outflow: implications for neurodegenerative disease diagnosis and monitoring. Anim Cells Syst (Seoul) 2024; 28:45-54. [PMID: 38292931 PMCID: PMC10826790 DOI: 10.1080/19768354.2024.2307559] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/28/2023] [Accepted: 01/15/2024] [Indexed: 02/01/2024] Open
Abstract
Cerebrospinal fluid (CSF) plays a crucial role in the brain's lymphatics as it traverses the central nervous system (CNS). Its primary function is to facilitate the outward transport of waste. Among the various CSF outflow pathways, the route through the cribriform plate along the olfactory nerves stands out as the most predominant. This review describes the outflow pathway of CSF into the nasal lymphatics. Additionally, we examine existing studies to describe mutual influences observed between the brain and extracranial regions due to this outflow pathway. Notably, pathological conditions in the CNS often influence CSF outflow, leading to observable changes in extracranial regions. The established connection between the brain and the nose is significant, and our review underscores its potential relevance in monitoring CNS ailments, including neurodegenerative diseases. Considering that aging - the most significant risk factor for the onset of neurodegeneration - is also a principal factor in CSF turnover alterations, we suggest a novel approach to studying neurodegenerative diseases in therapeutic terms.
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Affiliation(s)
- Jiwon Chae
- Department of Life Science, College of Natural Sciences, Hanyang University, Seoul, Republic of Korea
| | - Mina Choi
- Keybasic Co., ltd, Seoul, Republic of Korea
| | | | - Seung-Jun Yoo
- Department of Life Science, College of Natural Sciences, Hanyang University, Seoul, Republic of Korea
- Research Institute for Natural Sciences, Hanyang University, Seoul, Republic of Korea
- Research Institute for Convergence of Basic Sciences, Hanyang University, Seoul, Republic of Korea
- Hanyang Institute of Bioscience and Biotechnology, Hanyang University, Seoul, Republic of Korea
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4
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Yoon JH, Jin H, Kim HJ, Hong SP, Yang MJ, Ahn JH, Kim YC, Seo J, Lee Y, McDonald DM, Davis MJ, Koh GY. Nasopharyngeal lymphatic plexus is a hub for cerebrospinal fluid drainage. Nature 2024; 625:768-777. [PMID: 38200313 PMCID: PMC10808075 DOI: 10.1038/s41586-023-06899-4] [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: 03/28/2023] [Accepted: 11/24/2023] [Indexed: 01/12/2024]
Abstract
Cerebrospinal fluid (CSF) in the subarachnoid space around the brain has long been known to drain through the lymphatics to cervical lymph nodes1-17, but the connections and regulation have been challenging to identify. Here, using fluorescent CSF tracers in Prox1-GFP lymphatic reporter mice18, we found that the nasopharyngeal lymphatic plexus is a major hub for CSF outflow to deep cervical lymph nodes. This plexus had unusual valves and short lymphangions but no smooth-muscle coverage, whereas downstream deep cervical lymphatics had typical semilunar valves, long lymphangions and smooth muscle coverage that transported CSF to the deep cervical lymph nodes. α-Adrenergic and nitric oxide signalling in the smooth muscle cells regulated CSF drainage through the transport properties of deep cervical lymphatics. During ageing, the nasopharyngeal lymphatic plexus atrophied, but deep cervical lymphatics were not similarly altered, and CSF outflow could still be increased by adrenergic or nitric oxide signalling. Single-cell analysis of gene expression in lymphatic endothelial cells of the nasopharyngeal plexus of aged mice revealed increased type I interferon signalling and other inflammatory cytokines. The importance of evidence for the nasopharyngeal lymphatic plexus functioning as a CSF outflow hub is highlighted by its regression during ageing. Yet, the ageing-resistant pharmacological activation of deep cervical lymphatic transport towards lymph nodes can still increase CSF outflow, offering an approach for augmenting CSF clearance in age-related neurological conditions in which greater efflux would be beneficial.
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Affiliation(s)
- Jin-Hui Yoon
- Center for Vascular Research, Institute for Basic Science, Daejeon, Republic of Korea
| | - Hokyung Jin
- Center for Vascular Research, Institute for Basic Science, Daejeon, Republic of Korea
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Hae Jin Kim
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA
| | - Seon Pyo Hong
- Center for Vascular Research, Institute for Basic Science, Daejeon, Republic of Korea
| | - Myung Jin Yang
- Center for Vascular Research, Institute for Basic Science, Daejeon, Republic of Korea
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Ji Hoon Ahn
- Center for Vascular Research, Institute for Basic Science, Daejeon, Republic of Korea
| | - Young-Chan Kim
- Center for Vascular Research, Institute for Basic Science, Daejeon, Republic of Korea
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea
| | - Jincheol Seo
- National Primates Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, Republic of Korea
| | - Yongjeon Lee
- National Primates Research Center, Korea Research Institute of Bioscience and Biotechnology, Cheongju, Republic of Korea
| | - Donald M McDonald
- Department of Anatomy, Cardiovascular Research Institute, University of California, San Francisco, San Francisco, CA, USA
- Helen Diller Family Comprehensive Cancer Center, University of California, San Francisco, San Francisco, CA, USA
| | - Michael J Davis
- Department of Medical Pharmacology and Physiology, University of Missouri, Columbia, MO, USA.
| | - Gou Young Koh
- Center for Vascular Research, Institute for Basic Science, Daejeon, Republic of Korea.
- Graduate School of Medical Science and Engineering, Korea Advanced Institute of Science and Technology (KAIST), Daejeon, Republic of Korea.
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5
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Yang H, Wei XS, Gong J, Du XM, Feng HB, Su C, Gilmore C, Yue C, Yu SB, Li C, Sui HJ. The relationship between myodural bridge, atrophy and hyperplasia of the suboccipital musculature, and cerebrospinal fluid dynamics. Sci Rep 2023; 13:18882. [PMID: 37919345 PMCID: PMC10622500 DOI: 10.1038/s41598-023-45820-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: 04/08/2023] [Accepted: 10/24/2023] [Indexed: 11/04/2023] Open
Abstract
The Myodural Bridge (MDB) is a physiological structure that is highly conserved in mammals and many of other tetrapods. It connects the suboccipital muscles to the cervical spinal dura mater (SDM) and transmits the tensile forces generated by the suboccipital muscles to the SDM. Consequently, the MDB has broader physiological potentials than just fixing the SDM. It has been proposed that MDB significantly contributes to the dynamics of cerebrospinal fluid (CSF) movements. Animal models of suboccipital muscle atrophy and hyperplasia were established utilizing local injection of BTX-A and ACE-031. In contrast, animal models with surgical severance of suboccipital muscles, and without any surgical operation were set as two types of negative control groups. CSF secretion and reabsorption rates were then measured for subsequent analysis. Our findings demonstrated a significant increase in CSF secretion rate in rats with the hyperplasia model, while there was a significant decrease in rats with the atrophy and severance groups. We observed an increase in CSF reabsorption rate in both the atrophy and hyperplasia groups, but no significant change was observed in the severance group. Additionally, our immunohistochemistry results revealed no significant change in the protein level of six selected choroid plexus-CSF-related proteins among all these groups. Therefore, it was indicated that alteration of MDB-transmitted tensile force resulted in changes of CSF secretion and reabsorption rates, suggesting the potential role that MDB may play during CSF circulation. This provides a unique research insight into CSF dynamics.
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Affiliation(s)
- Heng Yang
- Department of Anatomy, Dalian Medical University, Dalian, Liaoning, China
| | - Xiao-Song Wei
- Department of Anatomy, Dalian Medical University, Dalian, Liaoning, China
| | - Jin Gong
- Department of Anatomy, Dalian Medical University, Dalian, Liaoning, China
| | - Xue-Mei Du
- Department of Nuclear Medicine, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Hong-Bo Feng
- Department of Nuclear Medicine, The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | - Chang Su
- The First Affiliated Hospital of Dalian Medical University, Dalian, Liaoning, China
| | | | - Chen Yue
- Department of Gynecology ands Obstetrics, Affiliated Zhongshan Hospital of Dalian University, Dalian, Liaoning, China
| | - Sheng-Bo Yu
- Department of Anatomy, Dalian Medical University, Dalian, Liaoning, China
| | - Chan Li
- Department of Anatomy, Dalian Medical University, Dalian, Liaoning, China.
| | - Hong-Jin Sui
- Department of Anatomy, Dalian Medical University, Dalian, Liaoning, China.
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6
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Vera Quesada CL, Rao SB, Torp R, Eide PK. Immunohistochemical visualization of lymphatic vessels in human dura mater: methodological perspectives. Fluids Barriers CNS 2023; 20:23. [PMID: 36978127 PMCID: PMC10044429 DOI: 10.1186/s12987-023-00426-3] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2022] [Accepted: 03/21/2023] [Indexed: 03/30/2023] Open
Abstract
BACKGROUND Despite greatly renewed interest concerning meningeal lymphatic function over recent years, the lymphatic structures of human dura mater have been less characterized. The available information derives exclusively from autopsy specimens. This study addressed methodological aspects of immunohistochemistry for visualization and characterization of lymphatic vessels in the dura of patients. METHODS Dura biopsies were obtained from the right frontal region of the patients with idiopathic normal pressure hydrocephalus (iNPH) who underwent shunt surgery as part of treatment. The dura specimens were prepared using three different methods: Paraformaldehyde (PFA) 4% (Method #1), paraformaldehyde (PFA) 0.5% (Method #2), and freeze-fixation (Method #3). They were further examined with immunohistochemistry using the lymphatic cell marker lymphatic vessel endothelial hyaluronan receptor 1 (LYVE-1), and as validation marker we used podoplanin (PDPN). RESULTS The study included 30 iNPH patients who underwent shunt surgery. The dura specimens were obtained average 16.1 ± 4.5 mm lateral to the superior sagittal sinus in the right frontal region (about 12 cm posterior to glabella). While lymphatic structures were seen in 0/7 patients using Method #1, it was found in 4/6 subjects (67%) with Method #2, while in 16/17 subjects (94%) using Method #3. To this end, we characterized three types of meningeal lymphatic vessels: (1) Lymphatic vessels in intimate contact with blood vessels. (2) Lymphatic vessels without nearby blood vessels. (3) Clusters of LYVE-1-expressing cells interspersed with blood vessels. In general, highest density of lymphatic vessels were observed towards the arachnoid membrane rather than towards the skull. CONCLUSIONS The visualization of meningeal lymphatic vessels in humans seems to be highly sensitive to the tissue processing method. Our observations disclosed most abundant lymphatic vessels towards the arachnoid membrane, and were seen either in close association with blood vessels or remote from blood vessels.
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Affiliation(s)
- César Luis Vera Quesada
- Department of Neurosurgery, Oslo University Hospital-Rikshospitalet, PB 4950 Nydalen, Oslo, 0424, Norway
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Shreyas Balachandra Rao
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Reidun Torp
- Division of Anatomy, Department of Molecular Medicine, Institute of Basic Medical Sciences, University of Oslo, Oslo, Norway
| | - Per Kristian Eide
- Department of Neurosurgery, Oslo University Hospital-Rikshospitalet, PB 4950 Nydalen, Oslo, 0424, Norway.
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
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Streptococcus pneumoniae Rapidly Translocate from the Nasopharynx through the Cribriform Plate to Invade the Outer Meninges. mBio 2022; 13:e0102422. [PMID: 35924840 PMCID: PMC9426477 DOI: 10.1128/mbio.01024-22] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022] Open
Abstract
The entry routes and translocation mechanisms of microorganisms or particulate materials into the central nervous system remain obscure We report here that Streptococcus pneumoniae (pneumococcus), or polystyrene microspheres of similar size, appear in the meninges of the dorsal cortex of mice within minutes of inhaled delivery. Recovery of viable bacteria from dissected tissue and fluorescence microscopy show that up to at least 72 h, pneumococci and microspheres were predominantly found in the outer of the two meninges: the pachymeninx. No pneumococci were found in blood or cerebrospinal fluid. Intravital imaging through the skull, aligned with flow cytometry showed recruitment and activation of LysM+ cells in the dorsal pachymeninx at 5 and 10 hours following intranasal infection. Imaging of the cribriform plate suggested that both pneumococci and microspheres entered through the foramina via an inward flow of fluid connecting the nose to the pachymeninx. Our findings bring new insight into the varied mechanisms of pneumococcal invasion of the central nervous system, but they are also pertinent to the delivery of drugs to the brain and the entry of airborne particulate matter into the cranium.
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Fang Y, Huang L, Wang X, Si X, Lenahan C, Shi H, Shao A, Tang J, Chen S, Zhang J, Zhang JH. A new perspective on cerebrospinal fluid dynamics after subarachnoid hemorrhage: From normal physiology to pathophysiological changes. J Cereb Blood Flow Metab 2022; 42:543-558. [PMID: 34806932 PMCID: PMC9051143 DOI: 10.1177/0271678x211045748] [Citation(s) in RCA: 19] [Impact Index Per Article: 9.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Knowledge about the dynamic metabolism and function of cerebrospinal fluid (CSF) physiology has rapidly progressed in recent decades. It has traditionally been suggested that CSF is produced by the choroid plexus and drains to the arachnoid villi. However, recent findings have revealed that the brain parenchyma produces a large portion of CSF and drains through the perivascular glymphatic system and meningeal lymphatic vessels into the blood. The primary function of CSF is not limited to maintaining physiological CNS homeostasis but also participates in clearing waste products resulting from neurodegenerative diseases and acute brain injury. Aneurysmal subarachnoid hemorrhage (SAH), a disastrous subtype of acute brain injury, is associated with high mortality and morbidity. Post-SAH complications contribute to the poor outcomes associated with SAH. Recently, abnormal CSF flow was suggested to play an essential role in the post-SAH pathophysiological changes, such as increased intracerebral pressure, brain edema formation, hydrocephalus, and delayed blood clearance. An in-depth understanding of CSF dynamics in post-SAH events would shed light on potential development of SAH treatment options. This review summarizes and updates the latest physiological characteristics of CSF dynamics and discusses potential pathophysiological changes and therapeutic targets after SAH.
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Affiliation(s)
- Yuanjian Fang
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Lei Huang
- Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA.,Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, CA, USA
| | - Xiaoyu Wang
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Xiaoli Si
- Department of Neurology, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Cameron Lenahan
- Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA.,Burrell College of Osteopathic Medicine, Las Cruces, NM, USA
| | - Hui Shi
- Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA.,Department of Neurosurgery, Yongchuan Hospital, Chongqing Medical University, Chongqing, China
| | - Anwen Shao
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jiping Tang
- Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA.,Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, CA, USA.,Department of Anesthesiology, Loma Linda University, Loma Linda, CA, USA
| | - Sheng Chen
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - Jianmin Zhang
- Department of Neurosurgery, The Second Affiliated Hospital, School of Medicine, Zhejiang University, Hangzhou, Zhejiang, China
| | - John H Zhang
- Department of Neurosurgery, Loma Linda University, Loma Linda, CA, USA.,Department of Physiology and Pharmacology, Loma Linda University, Loma Linda, CA, USA.,Department of Anesthesiology, Loma Linda University, Loma Linda, CA, USA
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9
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Xue Y, Gursky Z, Monte B, Koundal S, Liu X, Lee H, Michurina TV, Mellanson KA, Zhao L, Nemajerova A, Kahle KT, Takemaru KI, Enikolopov G, Peunova NI, Benveniste H. Sustained glymphatic transport and impaired drainage to the nasal cavity observed in multiciliated cell ciliopathies with hydrocephalus. Fluids Barriers CNS 2022; 19:20. [PMID: 35248089 PMCID: PMC8898469 DOI: 10.1186/s12987-022-00319-x] [Citation(s) in RCA: 6] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2021] [Accepted: 02/21/2022] [Indexed: 11/10/2022] Open
Abstract
Background Hydrocephalus (increased ventricular size due to CSF accumulation) is a common finding in human ciliopathies and in mouse models with genetic depletion of the multiciliated cell (MCC) cilia machinery. However, the contribution of MCC to CSF dynamics and, the mechanism by which impaired MCC function leads to hydrocephalus remains poorly understood. The aim of our study was to examine if defects in MCC ciliogenesis and cilia-generated CSF flow impact central nervous system (CNS) fluid homeostasis including glymphatic transport and solute waste drainage. Methods We used two distinct mouse models of MCC ciliopathy: MCC-specific CEP164 conditional knockout mice (FOXJ1-Cre;CEP164fl/fl (N = 10), 3-month-old) and p73 knock-out (p73−/− (N = 8), 5-month-old) mice. Age-matched, wild-type littermates for each of the mutants served as controls. Glymphatic transport and solute drainage was quantified using in vivo T1 mapping by magnetic resonance imaging (MRI) after CSF infusion of gadoteric acid. Brain morphometry and aquaporin 4 expression (AQP4) was also assessed. Intracranial pressure (ICP) was measured in separate cohorts. Results In both of the two models of MCC ciliopathy we found the ventriculomegaly to be associated with normal ICP. We showed that FOXJ1-Cre;CEP164fl/fl mice with hydrocephalus still demonstrated sustained glymphatic transport and normal AQP4 expression along capillaries. In p73−/− mice glymphatic transport was even increased, and this was paralleled by an increase in AQP4 polarization around capillaries. Further, solute drainage via the cribriform plate to the nasal cavity was severely impaired in both ciliopathy models and associated with chronic rhinitis and olfactory bulb hypoplasia. Conclusions The combination of sustained glymphatic transport, impaired solute drainage via the cribriform plate to the nasal cavity and hydrocephalus has not previously been reported in models of MCC ciliopathy. Our data enhance our understanding of how different types of ciliopathies contribute to disruption of CNS fluid homeostasis, manifested in pathologies such as hydrocephalus. Supplementary Information The online version contains supplementary material available at 10.1186/s12987-022-00319-x.
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10
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Mehta NH, Sherbansky J, Kamer AR, Carare RO, Butler T, Rusinek H, Chiang GC, Li Y, Strauss S, Saint-Louis LA, Theise ND, Suss RA, Blennow K, Kaplitt M, de Leon MJ. The Brain-Nose Interface: A Potential Cerebrospinal Fluid Clearance Site in Humans. Front Physiol 2022; 12:769948. [PMID: 35058794 PMCID: PMC8764168 DOI: 10.3389/fphys.2021.769948] [Citation(s) in RCA: 14] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/13/2021] [Accepted: 11/26/2021] [Indexed: 12/17/2022] Open
Abstract
The human brain functions at the center of a network of systems aimed at providing a structural and immunological layer of protection. The cerebrospinal fluid (CSF) maintains a physiological homeostasis that is of paramount importance to proper neurological activity. CSF is largely produced in the choroid plexus where it is continuous with the brain extracellular fluid and circulates through the ventricles. CSF movement through the central nervous system has been extensively explored. Across numerous animal species, the involvement of various drainage pathways in CSF, including arachnoid granulations, cranial nerves, perivascular pathways, and meningeal lymphatics, has been studied. Among these, there is a proposed CSF clearance route spanning the olfactory nerve and exiting the brain at the cribriform plate and entering lymphatics. While this pathway has been demonstrated in multiple animal species, evidence of a similar CSF egress mechanism involving the nasal cavity in humans remains poorly consolidated. This review will synthesize contemporary evidence surrounding CSF clearance at the nose-brain interface, examining across species this anatomical pathway, and its possible significance to human neurodegenerative disease. Our discussion of a bidirectional nasal pathway includes examination of the immune surveillance in the olfactory region protecting the brain. Overall, we expect that an expanded discussion of the brain-nose pathway and interactions with the environment will contribute to an improved understanding of neurodegenerative and infectious diseases, and potentially to novel prevention and treatment considerations.
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Affiliation(s)
- Neel H. Mehta
- Undergraduate Department of Biology, Cornell University, Ithaca, NY, United States
| | | | - Angela R. Kamer
- Department of Periodontology and Implant Dentistry, NYU College of Dentistry, New York, NY, United States
| | - Roxana O. Carare
- Department of Medicine, University of Southampton, Southampton, United Kingdom
| | - Tracy Butler
- Department of Radiology, Brain Health Imaging Institute, Weill Cornell Medicine, New York, NY, United States
| | - Henry Rusinek
- Department of Radiology, NYU Langone Health, New York, NY, United States
| | - Gloria C. Chiang
- Department of Radiology, Weill Cornell Medicine, New York, NY, United States
| | - Yi Li
- Department of Radiology, Brain Health Imaging Institute, Weill Cornell Medicine, New York, NY, United States
| | - Sara Strauss
- Department of Radiology, Weill Cornell Medicine, New York, NY, United States
| | - L. A. Saint-Louis
- Department of Radiology, NYU Langone Health, New York, NY, United States
| | - Neil D. Theise
- Department of Pathology, NYU Grossman School of Medicine, New York, NY, United States
| | - Richard A. Suss
- Division of Neuroradiology, Department of Radiology, University of Texas Southwestern Medical Center, Dallas, TX, United States
| | - Kaj Blennow
- Clinical Neurochemistry Lab, Inst. of Neuroscience and Physiology, University of Gothenburg, Sahlgrenska University Hospital, Göteborg, Sweden
| | - Michael Kaplitt
- Laboratory of Molecular Neurosurgery, Department of Neurological Surgery, Weill Cornell Medical College, New York, NY, United States
| | - Mony J. de Leon
- Department of Radiology, Brain Health Imaging Institute, Weill Cornell Medicine, New York, NY, United States
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11
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McAllister JP, Talcott MR, Isaacs AM, Zwick SH, Garcia-Bonilla M, Castaneyra-Ruiz L, Hartman AL, Dilger RN, Fleming SA, Golden RK, Morales DM, Harris CA, Limbrick DD. A novel model of acquired hydrocephalus for evaluation of neurosurgical treatments. Fluids Barriers CNS 2021; 18:49. [PMID: 34749745 PMCID: PMC8576945 DOI: 10.1186/s12987-021-00281-0] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/16/2021] [Accepted: 10/09/2021] [Indexed: 02/07/2023] Open
Abstract
Background Many animal models have been used to study the pathophysiology of hydrocephalus; most of these have been rodent models whose lissencephalic cerebral cortex may not respond to ventriculomegaly in the same way as gyrencephalic species and whose size is not amenable to evaluation of clinically relevant neurosurgical treatments. Fewer models of hydrocephalus in gyrencephalic species have been used; thus, we have expanded upon a porcine model of hydrocephalus in juvenile pigs and used it to explore surgical treatment methods. Methods Acquired hydrocephalus was induced in 33–41-day old pigs by percutaneous intracisternal injections of kaolin (n = 17). Controls consisted of sham saline-injected (n = 6) and intact (n = 4) animals. Magnetic resonance imaging (MRI) was employed to evaluate ventriculomegaly at 11–42 days post-kaolin and to plan the surgical implantation of ventriculoperitoneal shunts at 14–38-days post-kaolin. Behavioral and neurological status were assessed. Results Bilateral ventriculomegaly occurred post-induction in all regions of the cerebral ventricles, with prominent CSF flow voids in the third ventricle, foramina of Monro, and cerebral aqueduct. Kaolin deposits formed a solid cast in the basal cisterns but the cisterna magna was patent. In 17 untreated hydrocephalic animals. Mean total ventricular volume was 8898 ± 5917 SD mm3 at 11–43 days of age, which was significantly larger than the baseline values of 2251 ± 194 SD mm3 for 6 sham controls aged 45–55 days, (p < 0.001). Past the post-induction recovery period, untreated pigs were asymptomatic despite exhibiting mild-moderate ventriculomegaly. Three out of 4 shunted animals showed a reduction in ventricular volume after 20–30 days of treatment, however some developed ataxia and lethargy, from putative shunt malfunction. Conclusions Kaolin induction of acquired hydrocephalus in juvenile pigs produced an in vivo model that is highly translational, allowing systematic studies of the pathophysiology and clinical treatment of hydrocephalus. Supplementary Information The online version contains supplementary material available at 10.1186/s12987-021-00281-0.
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Affiliation(s)
- James P McAllister
- Department of Neurosurgery, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA. .,Department of Neurosurgery, BJC Institute of Health, 425 S. Euclid, Campus, Box 8057, St. Louis, MO, 63143, USA.
| | - Michael R Talcott
- Department of Neurosurgery, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA.,Division of Comparative Medicine, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA
| | - Albert M Isaacs
- Department of Surgery, Division of Neurosurgery, University of Calgary School of Medicine, Calgary, AB, T2N 2T9, Canada
| | - Sarah H Zwick
- Department of Neurosurgery, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA
| | - Maria Garcia-Bonilla
- Department of Neurosurgery, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA
| | - Leandro Castaneyra-Ruiz
- Department of Neurosurgery, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA
| | - Alexis L Hartman
- Department of Neurosurgery, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA
| | - Ryan N Dilger
- Department of Animal Sciences, Division of Nutritional Sciences, Neuroscience Program, University of Illinois, Champagne-Urbana, Illinois, 61801, USA.,Traverse Science, Champaign, IL, 61801, USA
| | - Stephen A Fleming
- Department of Animal Sciences, Division of Nutritional Sciences, Neuroscience Program, University of Illinois, Champagne-Urbana, Illinois, 61801, USA.,Traverse Science, Champaign, IL, 61801, USA
| | - Rebecca K Golden
- Department of Animal Sciences, Division of Nutritional Sciences, Neuroscience Program, University of Illinois, Champagne-Urbana, Illinois, 61801, USA
| | - Diego M Morales
- Department of Neurosurgery, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA
| | - Carolyn A Harris
- Department of Chemical Engineering and Materials Science, Wayne State University, Detroit, MI, 48202 , USA.,Department of Neurosurgery, Wayne State University School of Medicine, Detroit, MI, 48202, USA
| | - David D Limbrick
- Department of Neurosurgery, Washington University in St. Louis School of Medicine, St. Louis, MO, 63110, USA.,Department of Pediatrics, St. Louis Children's Hospital, St. Louis, MO, 63110, USA
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12
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Kaur J, Fahmy LM, Davoodi-Bojd E, Zhang L, Ding G, Hu J, Zhang Z, Chopp M, Jiang Q. Waste Clearance in the Brain. Front Neuroanat 2021; 15:665803. [PMID: 34305538 PMCID: PMC8292771 DOI: 10.3389/fnana.2021.665803] [Citation(s) in RCA: 25] [Impact Index Per Article: 8.3] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/11/2021] [Accepted: 06/15/2021] [Indexed: 12/15/2022] Open
Abstract
Waste clearance (WC) is an essential process for brain homeostasis, which is required for the proper and healthy functioning of all cerebrovascular and parenchymal brain cells. This review features our current understanding of brain WC, both within and external to the brain parenchyma. We describe the interplay of the blood-brain barrier (BBB), interstitial fluid (ISF), and perivascular spaces within the brain parenchyma for brain WC directly into the blood and/or cerebrospinal fluid (CSF). We also discuss the relevant role of the CSF and its exit routes in mediating WC. Recent discoveries of the glymphatic system and meningeal lymphatic vessels, and their relevance to brain WC are highlighted. Controversies related to brain WC research and potential future directions are presented.
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Affiliation(s)
- Jasleen Kaur
- Department of Neurology, Henry Ford Health System, Detroit, MI, United States
- Department of Physics, Oakland University, Rochester, MI, United States
| | - Lara M. Fahmy
- Department of Neurology, Henry Ford Health System, Detroit, MI, United States
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University, Detroit, MI, United States
| | - Esmaeil Davoodi-Bojd
- Department of Neurology, Henry Ford Health System, Detroit, MI, United States
- Department of Radiology, Henry Ford Health System, Detroit, MI, United States
| | - Li Zhang
- Department of Neurology, Henry Ford Health System, Detroit, MI, United States
| | - Guangliang Ding
- Department of Neurology, Henry Ford Health System, Detroit, MI, United States
| | - Jiani Hu
- Department of Radiology, Wayne State University, Detroit, MI, United States
| | - Zhenggang Zhang
- Department of Neurology, Henry Ford Health System, Detroit, MI, United States
- Department of Neurology, Wayne State University, 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
| | - Quan Jiang
- Department of Neurology, Henry Ford Health System, Detroit, MI, United States
- Department of Physics, Oakland University, Rochester, MI, United States
- Department of Neurology, Wayne State University, Detroit, MI, United States
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13
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Hsu M, Laaker C, Sandor M, Fabry Z. Neuroinflammation-Driven Lymphangiogenesis in CNS Diseases. Front Cell Neurosci 2021; 15:683676. [PMID: 34248503 PMCID: PMC8261156 DOI: 10.3389/fncel.2021.683676] [Citation(s) in RCA: 6] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/21/2021] [Accepted: 05/05/2021] [Indexed: 11/13/2022] Open
Abstract
The central nervous system (CNS) undergoes immunosurveillance despite the lack of conventional antigen presenting cells and lymphatic vessels in the CNS parenchyma. Additionally, the CNS is bathed in a cerebrospinal fluid (CSF). CSF is continuously produced, and consequently must continuously clear to maintain fluid homeostasis despite the lack of conventional lymphatics. During neuroinflammation, there is often an accumulation of fluid, antigens, and immune cells to affected areas of the brain parenchyma. Failure to effectively drain these factors may result in edema, prolonged immune response, and adverse clinical outcome as observed in conditions including traumatic brain injury, ischemic and hypoxic brain injury, CNS infection, multiple sclerosis (MS), and brain cancer. Consequently, there has been renewed interest surrounding the expansion of lymphatic vessels adjacent to the CNS which are now thought to be central in regulating the drainage of fluid, cells, and waste out of the CNS. These lymphatic vessels, found at the cribriform plate, dorsal dural meninges, base of the brain, and around the spinal cord have each been implicated to have important roles in various CNS diseases. In this review, we discuss the contribution of meningeal lymphatics to these processes during both steady-state conditions and neuroinflammation, as well as discuss some of the many still unknown aspects regarding the role of meningeal lymphatics in neuroinflammation. Specifically, we focus on the observed phenomenon of lymphangiogenesis by a subset of meningeal lymphatics near the cribriform plate during neuroinflammation, and discuss their potential roles in immunosurveillance, fluid clearance, and access to the CSF and CNS compartments. We propose that manipulating CNS lymphatics may be a new therapeutic way to treat CNS infections, stroke, and autoimmunity.
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Affiliation(s)
- Martin Hsu
- Neuroscience Training Program, University of Wisconsin Madison, Madison, WI, United States
| | - Collin Laaker
- Neuroscience Training Program, University of Wisconsin Madison, Madison, WI, United States
| | - Matyas Sandor
- Department of Pathology and Laboratory Medicine, University of Wisconsin Madison, Madison, WI, United States
| | - Zsuzsanna Fabry
- Department of Pathology and Laboratory Medicine, University of Wisconsin Madison, Madison, WI, United States
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14
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Xu H, Fame RM, Sadegh C, Sutin J, Naranjo C, Della Syau, Cui J, Shipley FB, Vernon A, Gao F, Zhang Y, Holtzman MJ, Heiman M, Warf BC, Lin PY, Lehtinen MK. Choroid plexus NKCC1 mediates cerebrospinal fluid clearance during mouse early postnatal development. Nat Commun 2021; 12:447. [PMID: 33469018 PMCID: PMC7815709 DOI: 10.1038/s41467-020-20666-3] [Citation(s) in RCA: 58] [Impact Index Per Article: 19.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2020] [Accepted: 12/10/2020] [Indexed: 12/14/2022] Open
Abstract
Cerebrospinal fluid (CSF) provides vital support for the brain. Abnormal CSF accumulation, such as hydrocephalus, can negatively affect perinatal neurodevelopment. The mechanisms regulating CSF clearance during the postnatal critical period are unclear. Here, we show that CSF K+, accompanied by water, is cleared through the choroid plexus (ChP) during mouse early postnatal development. We report that, at this developmental stage, the ChP showed increased ATP production and increased expression of ATP-dependent K+ transporters, particularly the Na+, K+, Cl-, and water cotransporter NKCC1. Overexpression of NKCC1 in the ChP resulted in increased CSF K+ clearance, increased cerebral compliance, and reduced circulating CSF in the brain without changes in intracranial pressure in mice. Moreover, ChP-specific NKCC1 overexpression in an obstructive hydrocephalus mouse model resulted in reduced ventriculomegaly. Collectively, our results implicate NKCC1 in regulating CSF K+ clearance through the ChP in the critical period during postnatal neurodevelopment in mice.
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Affiliation(s)
- Huixin Xu
- Department of Pathology, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Ryann M Fame
- Department of Pathology, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Cameron Sadegh
- Department of Pathology, Boston Children's Hospital, Boston, MA, 02115, USA
- Department of Neurosurgery, Massachusetts General Hospital and Harvard Medical School, Boston, MA, 02114, USA
| | - Jason Sutin
- Fetal-Neonatal Neuroimaging and Developmental Science Center, Division of Newborn Medicine, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Christopher Naranjo
- Summer Honors Undergraduate Research Program, Division of Medical Sciences, Harvard Medical School, Boston, MA, 02115, USA
| | - Della Syau
- Summer Honors Undergraduate Research Program, Division of Medical Sciences, Harvard Medical School, Boston, MA, 02115, USA
| | - Jin Cui
- Department of Pathology, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Frederick B Shipley
- Department of Pathology, Boston Children's Hospital, Boston, MA, 02115, USA
- Graduate Program in Biophysics, Harvard University, Cambridge, MA, 02138, USA
| | - Amanda Vernon
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- Picower Institute for Learning and Memory, Cambridge, MA, 02139, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Fan Gao
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- Picower Institute for Learning and Memory, Cambridge, MA, 02139, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
- Bioinformatics Resource Center in the Beckman Institute at Caltech, Pasadena, CA, 91125, USA
| | - Yong Zhang
- Pulmonary and Critical Care Medicine, Department of Medicine, Washington University, St. Louis, MO, 63110, USA
| | - Michael J Holtzman
- Pulmonary and Critical Care Medicine, Department of Medicine, Washington University, St. Louis, MO, 63110, USA
| | - Myriam Heiman
- Broad Institute of MIT and Harvard, Cambridge, MA, 02142, USA
- Picower Institute for Learning and Memory, Cambridge, MA, 02139, USA
- Department of Brain and Cognitive Sciences, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA
| | - Benjamin C Warf
- Department of Neurosurgery, Boston Children's Hospital, Boston, MA, 02115, USA
| | - Pei-Yi Lin
- Fetal-Neonatal Neuroimaging and Developmental Science Center, Division of Newborn Medicine, Boston Children's Hospital, Harvard Medical School, 300 Longwood Avenue, Boston, MA, 02115, USA
| | - Maria K Lehtinen
- Department of Pathology, Boston Children's Hospital, Boston, MA, 02115, USA.
- Graduate Program in Biophysics, Harvard University, Cambridge, MA, 02138, USA.
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15
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Proulx ST. Cerebrospinal fluid outflow: a review of the historical and contemporary evidence for arachnoid villi, perineural routes, and dural lymphatics. Cell Mol Life Sci 2021; 78:2429-2457. [PMID: 33427948 PMCID: PMC8004496 DOI: 10.1007/s00018-020-03706-5] [Citation(s) in RCA: 153] [Impact Index Per Article: 51.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/02/2020] [Revised: 10/23/2020] [Accepted: 11/06/2020] [Indexed: 12/19/2022]
Abstract
Cerebrospinal fluid (CSF) is produced by the choroid plexuses within the ventricles of the brain and circulates through the subarachnoid space of the skull and spinal column to provide buoyancy to and maintain fluid homeostasis of the brain and spinal cord. The question of how CSF drains from the subarachnoid space has long puzzled scientists and clinicians. For many decades, it was believed that arachnoid villi or granulations, outcroppings of arachnoid tissue that project into the dural venous sinuses, served as the major outflow route. However, this concept has been increasingly challenged in recent years, as physiological and imaging evidence from several species has accumulated showing that tracers injected into the CSF can instead be found within lymphatic vessels draining from the cranium and spine. With the recent high-profile rediscovery of meningeal lymphatic vessels located in the dura mater, another debate has emerged regarding the exact anatomical pathway(s) for CSF to reach the lymphatic system, with one side favoring direct efflux to the dural lymphatic vessels within the skull and spinal column and another side advocating for pathways along exiting cranial and spinal nerves. In this review, a summary of the historical and contemporary evidence for the different outflow pathways will be presented, allowing the reader to gain further perspective on the recent advances in the field. An improved understanding of this fundamental physiological process may lead to novel therapeutic approaches for a wide range of neurological conditions, including hydrocephalus, neurodegeneration and multiple sclerosis.
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Affiliation(s)
- Steven T Proulx
- Theodor Kocher Institute, University of Bern, Bern, Switzerland.
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16
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Li L, Chopp M, Ding G, Davoodi-Bojd E, Zhang L, Li Q, Zhang Y, Xiong Y, Jiang Q. MRI detection of impairment of glymphatic function in rat after mild traumatic brain injury. Brain Res 2020; 1747:147062. [PMID: 32818526 PMCID: PMC9419050 DOI: 10.1016/j.brainres.2020.147062] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/10/2020] [Revised: 08/02/2020] [Accepted: 08/14/2020] [Indexed: 12/19/2022]
Abstract
We investigated the effect of mild traumatic brain injury (mTBI) on the glymphatic pathway using contrast-enhanced magnetic resonance imaging (CE-MRI) and quantified with kinetic parameters obtained from an advanced two-compartment model. mTBI was induced in male Wistar rats using a closed head impact. Animals with and without mTBI (n = 7/group) underwent the identical MRI protocol 10-weeks post-injury, including T2-weighted imaging and 3D T1-weighted imaging with intra-cisterna magna injection of contrast agent (Gd-DTPA). The parameters of infusion rate, clearance rate and clearance time constant, characterizing the kinetic features of glymphatic tracer transport in a living brain, were quantified in multiple brain tissue regions. In the majority of examined regions, our quantification demonstrated significantly reduced infusion and clearance rates, and significantly increased clearance time constant in the mTBI animals compared to the healthy controls. These data indicate that mTBI induces chronic changes in influx and efflux of contrast agent and glymphatic pathway dysfunction. While the reduced efficiency of glymphatic function after mTBI was apparent in brain, regional evaluation revealed heterogeneous glymphatic effects of the mTBI in different anatomical regions. The suppression of glymphatic function, rather than the presence of focal lesions, indicates a persistent injury of the brain after mTBI. Thus, dynamic CE-MRI in conjunction with advanced kinetic analysis may offer a useful methodology for an objective assessment and confirmatory diagnosis of mTBI.
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Affiliation(s)
- Lian Li
- Department of Neurology, Henry Ford Health System, Detroit, MI 48202, USA.
| | - Michael Chopp
- Department of Neurology, Henry Ford Health System, Detroit, MI 48202, USA; Department of Physics, Oakland University, Rochester, MI 48309, USA.
| | - Guangliang Ding
- Department of Neurology, Henry Ford Health System, Detroit, MI 48202, USA.
| | | | - Li Zhang
- Department of Neurology, Henry Ford Health System, Detroit, MI 48202, USA.
| | - Qingjiang Li
- Department of Neurology, Henry Ford Health System, Detroit, MI 48202, USA.
| | - Yanlu Zhang
- Department of Neurosurgery, Henry Ford Health System, Detroit, MI 48208, USA.
| | - Ye Xiong
- Department of Neurosurgery, Henry Ford Health System, Detroit, MI 48208, USA.
| | - Quan Jiang
- Department of Neurology, Henry Ford Health System, Detroit, MI 48202, USA.
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17
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Melin E, Eide PK, Ringstad G. In vivo assessment of cerebrospinal fluid efflux to nasal mucosa in humans. Sci Rep 2020; 10:14974. [PMID: 32917953 PMCID: PMC7486888 DOI: 10.1038/s41598-020-72031-5] [Citation(s) in RCA: 28] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/05/2020] [Accepted: 08/14/2020] [Indexed: 01/24/2023] Open
Abstract
Extra-vascular molecular clearance routes from the brain and cerebrospinal fluid (CSF) remain insufficiently characterized in humans. Animal studies consistently suggest that the cribriform plate and nasal lymphatic vessels are crucial for molecular clearance from CSF. In this study, we aimed to examine human in vivo transport of a CSF tracer from CSF to nasal mucosa. We hypothesised a CSF tracer would enrich in nasal mucosa provided that nasal lymphatic drainage has a significant role in CSF molecular clearance. Consecutive magnetic resonance imaging during 48 h after intrathecal administration of a tracer (gadobutrol) was performed in 24 patients. Despite a strong enrichment of CSF tracer in CSF spaces nearby the cribriform plate, there was no significant enrichment of CSF tracer in nasal mucosa, as measured in superior, medial and inferior turbinates, or in the nasal septum. Therefore, this in vivo study questions the importance of CSF drainage to the human nasal mucosa and emphasizes the need of further human studies.
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Affiliation(s)
- Erik Melin
- Department of Radiology, Østfold Hospital Trust, Grålum, Norway
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway
| | - Per Kristian Eide
- Institute of Clinical Medicine, Faculty of Medicine, University of Oslo, Oslo, Norway.
- Department of Neurosurgery, Oslo University Hospital-Rikshospitalet, Oslo, Norway.
| | - Geir Ringstad
- Department of Radiology and Nuclear Medicine, Oslo University Hospital-Rikshospitalet, Oslo, Norway
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18
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Kaur J, Davoodi-Bojd E, Fahmy LM, Zhang L, Ding G, Hu J, Zhang Z, Chopp M, Jiang Q. Magnetic Resonance Imaging and Modeling of the Glymphatic System. Diagnostics (Basel) 2020; 10:diagnostics10060344. [PMID: 32471025 PMCID: PMC7344900 DOI: 10.3390/diagnostics10060344] [Citation(s) in RCA: 14] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/17/2020] [Revised: 05/22/2020] [Accepted: 05/25/2020] [Indexed: 12/20/2022] Open
Abstract
The glymphatic system is a newly discovered waste drainage pathway in the brain; it plays an important role in many neurological diseases. Ongoing research utilizing various cerebrospinal fluid tracer infusions, either directly or indirectly into the brain parenchyma, is investigating clearance pathways by using distinct imaging techniques. In the present review, we discuss the role of the glymphatic system in various neurological diseases and efflux pathways of brain waste clearance based on current evidence and controversies. We mainly focus on new magnetic resonance imaging (MRI) modeling techniques, along with traditional computational modeling, for a better understanding of the glymphatic system function. Future sophisticated modeling techniques hold the potential to generate quantitative maps for glymphatic system parameters that could contribute to the diagnosis, monitoring, and prognosis of neurological diseases. The non-invasive nature of MRI may provide a safe and effective way to translate glymphatic system measurements from bench-to-bedside.
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Affiliation(s)
- Jasleen Kaur
- Department of Neurology, Henry Ford Health System, Detroit, MI 48202, USA; (J.K.); (E.D.-B.); (L.M.F.); (L.Z.); (G.D.); (Z.Z.); (M.C.)
- Department of Physics, Oakland University, Rochester, MI 48309, USA
| | - Esmaeil Davoodi-Bojd
- Department of Neurology, Henry Ford Health System, Detroit, MI 48202, USA; (J.K.); (E.D.-B.); (L.M.F.); (L.Z.); (G.D.); (Z.Z.); (M.C.)
- Department of Radiology, Henry Ford Health System, Detroit, MI 48202, USA
| | - Lara M Fahmy
- Department of Neurology, Henry Ford Health System, Detroit, MI 48202, USA; (J.K.); (E.D.-B.); (L.M.F.); (L.Z.); (G.D.); (Z.Z.); (M.C.)
- Department of Psychiatry and Behavioral Neurosciences, Wayne State University, Detroit, MI 48201, USA
| | - Li Zhang
- Department of Neurology, Henry Ford Health System, Detroit, MI 48202, USA; (J.K.); (E.D.-B.); (L.M.F.); (L.Z.); (G.D.); (Z.Z.); (M.C.)
| | - Guangliang Ding
- Department of Neurology, Henry Ford Health System, Detroit, MI 48202, USA; (J.K.); (E.D.-B.); (L.M.F.); (L.Z.); (G.D.); (Z.Z.); (M.C.)
| | - Jiani Hu
- Department of Radiology, Wayne State University, Detroit, MI 48201, USA;
| | - Zhenggang Zhang
- Department of Neurology, Henry Ford Health System, Detroit, MI 48202, USA; (J.K.); (E.D.-B.); (L.M.F.); (L.Z.); (G.D.); (Z.Z.); (M.C.)
| | - Michael Chopp
- Department of Neurology, Henry Ford Health System, Detroit, MI 48202, USA; (J.K.); (E.D.-B.); (L.M.F.); (L.Z.); (G.D.); (Z.Z.); (M.C.)
- Department of Physics, Oakland University, Rochester, MI 48309, USA
| | - Quan Jiang
- Department of Neurology, Henry Ford Health System, Detroit, MI 48202, USA; (J.K.); (E.D.-B.); (L.M.F.); (L.Z.); (G.D.); (Z.Z.); (M.C.)
- Department of Physics, Oakland University, Rochester, MI 48309, USA
- Correspondence: ; Tel.: +1-313-916-8735; Fax: +1-313-916-1324
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19
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Abstract
Given its poor prognosis, glioblastoma represents an area of high unmet clinical need. Standard of care for the treatment of glioblastoma in the frontline setting is limited to surgical resection, radiation, and temozolomide, with the more recent addition of Tumor Treating Fields. Several agents, including bevacizumab, lomustine, and carmustine have been approved in the recurrent setting. To date, no therapies have demonstrated substantial survival benefit beyond standard of care. An expanding understanding of the role of the immune system in fighting cancer has led to the development and approval of various immunotherapeutic approaches across solid tumors. In glioblastoma, the notion of a highly immune-restricted central nervous system has also evolved, further providing the rationale for testing therapies that promote immune trafficking to the CNS and infiltration into the tumor to counteract the immunosuppressive mechanisms that support tumor progression. There are five broad categories of immunotherapies currently being tested in GBM: vaccines, cytokine therapy, oncolytic viral therapy, chimeric antigen receptor T cell therapy, and checkpoint inhibitors. This review focuses on checkpoint inhibitors in GBM, the rationale for its use, preclinical data, and early clinical experience. Efficacy data are limited, and while a number of late-stage trials are ongoing, early trials showed no benefit in survival. There is a dizzying array of combinations being tested in clinical studies with an urgent need for a rational approach to determine the role of checkpoint inhibitors in glioblastoma, including the optimal combinations, and identification of biomarkers or predictive models to determine which patients may benefit from immunotherapy.
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20
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Liu KC, Fleischman D, Lee AG, Killer HE, Chen JJ, Bhatti MT. Current concepts of cerebrospinal fluid dynamics and the translaminar cribrosa pressure gradient: a paradigm of optic disk disease. Surv Ophthalmol 2020; 65:48-66. [DOI: 10.1016/j.survophthal.2019.08.005] [Citation(s) in RCA: 12] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/29/2019] [Revised: 08/07/2019] [Accepted: 08/16/2019] [Indexed: 12/11/2022]
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21
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Eichele G, Bodenschatz E, Ditte Z, Günther AK, Kapoor S, Wang Y, Westendorf C. Cilia-driven flows in the brain third ventricle. Philos Trans R Soc Lond B Biol Sci 2019; 375:20190154. [PMID: 31884922 DOI: 10.1098/rstb.2019.0154] [Citation(s) in RCA: 16] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Abstract
The brain ventricles are interconnected, elaborate cavities that traverse the brain. They are filled with cerebrospinal fluid (CSF) that is, to a large part, produced by the choroid plexus, a secretory epithelium that reaches into the ventricles. CSF is rich in cytokines, growth factors and extracellular vesicles that glide along the walls of ventricles, powered by bundles of motile cilia that coat the ventricular wall. We review the cellular and biochemical properties of the ventral part of the third ventricle that is surrounded by the hypothalamus. In particular, we consider the recently discovered intricate network of cilia-driven flows that characterize this ventricle and discuss the potential physiological significance of this flow for the directional transport of CSF signals to cellular targets located either within the third ventricle or in the adjacent hypothalamic brain parenchyma. Cilia-driven streams of signalling molecules offer an exciting perspective on how fluid-borne signals are dynamically transmitted in the brain. This article is part of the Theo Murphy meeting issue 'Unity and diversity of cilia in locomotion and transport'.
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Affiliation(s)
- Gregor Eichele
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Eberhard Bodenschatz
- Max Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, 37077 Göttingen, Germany
| | - Zuzana Ditte
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Ann-Kathrin Günther
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Shoba Kapoor
- Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, 37077 Göttingen, Germany
| | - Yong Wang
- Max Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, 37077 Göttingen, Germany
| | - Christian Westendorf
- Max Planck Institute for Dynamics and Self-Organization, Am Fassberg 17, 37077 Göttingen, Germany
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22
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Norwood JN, Zhang Q, Card D, Craine A, Ryan TM, Drew PJ. Anatomical basis and physiological role of cerebrospinal fluid transport through the murine cribriform plate. eLife 2019; 8:44278. [PMID: 31063132 PMCID: PMC6524970 DOI: 10.7554/elife.44278] [Citation(s) in RCA: 73] [Impact Index Per Article: 14.6] [Reference Citation Analysis] [Abstract] [Key Words] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/10/2018] [Accepted: 05/06/2019] [Indexed: 12/25/2022] Open
Abstract
Cerebrospinal fluid (CSF) flows through the brain, transporting chemical signals and removing waste. CSF production in the brain is balanced by a constant outflow of CSF, the anatomical basis of which is poorly understood. Here, we characterized the anatomy and physiological function of the CSF outflow pathway along the olfactory sensory nerves through the cribriform plate, and into the nasal epithelia. Chemical ablation of olfactory sensory nerves greatly reduced outflow of CSF through the cribriform plate. The reduction in CSF outflow did not cause an increase in intracranial pressure (ICP), consistent with an alteration in the pattern of CSF drainage or production. Our results suggest that damage to olfactory sensory neurons (such as from air pollution) could contribute to altered CSF turnover and flow, providing a potential mechanism for neurological diseases.
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Affiliation(s)
- Jordan N Norwood
- Cellular and Developmental Biology Graduate Program, Pennsylvania State University, University Park, United States
| | - Qingguang Zhang
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, United States
| | - David Card
- Department of Physics, Pennsylvania State University, University Park, United States
| | - Amanda Craine
- Department of Biomedical Engineering, Pennsylvania State University, University Park, United States
| | - Timothy M Ryan
- Department of Anthropology, Pennsylvania State University, University Park, United States
| | - Patrick J Drew
- Department of Engineering Science and Mechanics, Pennsylvania State University, University Park, United States.,Department of Biomedical Engineering, Pennsylvania State University, University Park, United States.,Department of Neurosurgery, Pennsylvania State University, University Park, United States
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23
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Bothwell SW, Janigro D, Patabendige A. Cerebrospinal fluid dynamics and intracranial pressure elevation in neurological diseases. Fluids Barriers CNS 2019; 16:9. [PMID: 30967147 PMCID: PMC6456952 DOI: 10.1186/s12987-019-0129-6] [Citation(s) in RCA: 122] [Impact Index Per Article: 24.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/10/2019] [Accepted: 03/19/2019] [Indexed: 01/09/2023] Open
Abstract
The fine balance between the secretion, composition, volume and turnover of cerebrospinal fluid (CSF) is strictly regulated. However, during certain neurological diseases, this balance can be disrupted. A significant disruption to the normal CSF circulation can be life threatening, leading to increased intracranial pressure (ICP), and is implicated in hydrocephalus, idiopathic intracranial hypertension, brain trauma, brain tumours and stroke. Yet, the exact cellular, molecular and physiological mechanisms that contribute to altered hydrodynamic pathways in these diseases are poorly defined or hotly debated. The traditional views and concepts of CSF secretion, flow and drainage have been challenged, also due to recent findings suggesting more complex mechanisms of brain fluid dynamics than previously proposed. This review evaluates and summarises current hypotheses of CSF dynamics and presents evidence for the role of impaired CSF dynamics in elevated ICP, alongside discussion of the proteins that are potentially involved in altered CSF physiology during neurological disease. Undoubtedly CSF secretion, absorption and drainage are important aspects of brain fluid homeostasis in maintaining a stable ICP. Traditionally, pharmacological interventions or CSF drainage have been used to reduce ICP elevation due to over production of CSF. However, these drugs are used only as a temporary solution due to their undesirable side effects. Emerging evidence suggests that pharmacological targeting of aquaporins, transient receptor potential vanilloid type 4 (TRPV4), and the Na+-K+-2Cl- cotransporter (NKCC1) merit further investigation as potential targets in neurological diseases involving impaired brain fluid dynamics and elevated ICP.
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Affiliation(s)
- Steven William Bothwell
- Brain Barriers Group, School of Biomedical Sciences and Pharmacy, The University of Newcastle, Medical Sciences Building, University Drive, Callaghan, NSW 2308 Australia
| | - Damir Janigro
- FloTBI Inc., Cleveland, OH USA
- Department of Physiology, Case Western Reserve University, Cleveland, OH USA
| | - Adjanie Patabendige
- Brain Barriers Group, School of Biomedical Sciences and Pharmacy, The University of Newcastle, Medical Sciences Building, University Drive, Callaghan, NSW 2308 Australia
- Hunter Medical Research Institute, Newcastle, NSW Australia
- The Institute of Infection and Global Health, University of Liverpool, Liverpool, UK
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24
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An undescribed venous pathway intervening between the olfactory fossa and nasal vestibule. Surg Radiol Anat 2019; 41:485-490. [PMID: 30783738 DOI: 10.1007/s00276-019-02208-9] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Accepted: 02/12/2019] [Indexed: 10/27/2022]
Abstract
PURPOSE A curvilinear pathway intervening between the olfactory fossa and nasal vestibule has not been well documented. Therefore, the aim of this study was to examine its structure using magnetic resonance imaging (MRI). METHODS In total, 84 patients underwent thin-sliced, contrast MRI. Among these patients, 31 underwent additional thin-sliced, sagittal T2-weighted imaging. RESULTS A curvilinear pathway intervening between the olfactory fossa and nasal vestibule was delineated on sagittal and coronal imaging in 98% and 82% of patients, respectively. All of these pathways demonstrated communication with the lower limit of the superior sagittal sinus (SSS) or fine venous channels connecting to the SSS in the vicinity of the crista galli. The pathway was identified in the parasagittal regions on both sides with varying lengths, diameters, and curvatures. In 94% of the patients who underwent sagittal T2-weighted imaging, the pathways appeared as linear high-intensity signals. Most pathways were delineated as a single channel coursing extracranially adjacent to the olfactory fossa. In 38% of the patients, post-contrast sagittal images showed variable filling defects between the olfactory bulb and floor of the olfactory fossa, furthermore traversing the venous pathway. Additionally, in 73% of the patients, post-contrast images identified diploic venous channels, variably in the nasal bone and communicating with the venous pathway. CONCLUSIONS A curvilinear pathway intervening between the olfactory fossa and nasal vestibule is a consistent venous structure and may function as an extracranial route of cerebrospinal fluid drainage.
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Abstract
Glucose is the long-established, obligatory fuel for brain that fulfills many critical functions, including ATP production, oxidative stress management, and synthesis of neurotransmitters, neuromodulators, and structural components. Neuronal glucose oxidation exceeds that in astrocytes, but both rates increase in direct proportion to excitatory neurotransmission; signaling and metabolism are closely coupled at the local level. Exact details of neuron-astrocyte glutamate-glutamine cycling remain to be established, and the specific roles of glucose and lactate in the cellular energetics of these processes are debated. Glycolysis is preferentially upregulated during brain activation even though oxygen availability is sufficient (aerobic glycolysis). Three major pathways, glycolysis, pentose phosphate shunt, and glycogen turnover, contribute to utilization of glucose in excess of oxygen, and adrenergic regulation of aerobic glycolysis draws attention to astrocytic metabolism, particularly glycogen turnover, which has a high impact on the oxygen-carbohydrate mismatch. Aerobic glycolysis is proposed to be predominant in young children and specific brain regions, but re-evaluation of data is necessary. Shuttling of glucose- and glycogen-derived lactate from astrocytes to neurons during activation, neurotransmission, and memory consolidation are controversial topics for which alternative mechanisms are proposed. Nutritional therapy and vagus nerve stimulation are translational bridges from metabolism to clinical treatment of diverse brain disorders.
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Affiliation(s)
- Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences , Little Rock, Arkansas ; and Department of Cell Biology and Physiology, University of New Mexico , Albuquerque, New Mexico
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26
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Hsu M, Rayasam A, Kijak JA, Choi YH, Harding JS, Marcus SA, Karpus WJ, Sandor M, Fabry Z. Neuroinflammation-induced lymphangiogenesis near the cribriform plate contributes to drainage of CNS-derived antigens and immune cells. Nat Commun 2019; 10:229. [PMID: 30651548 PMCID: PMC6335416 DOI: 10.1038/s41467-018-08163-0] [Citation(s) in RCA: 114] [Impact Index Per Article: 22.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/25/2018] [Accepted: 12/07/2018] [Indexed: 02/07/2023] Open
Abstract
There are no conventional lymphatic vessels within the CNS parenchyma, although it has been hypothesized that lymphatics near the cribriform plate or dura maintain fluid homeostasis and immune surveillance during steady-state conditions. However, the role of these lymphatic vessels during neuroinflammation is not well understood. We report that lymphatic vessels near the cribriform plate undergo lymphangiogenesis in a VEGFC – VEGFR3 dependent manner during experimental autoimmune encephalomyelitis (EAE) and drain both CSF and cells that were once in the CNS parenchyma. Lymphangiogenesis also contributes to the drainage of CNS derived antigens that leads to antigen specific T cell proliferation in the draining lymph nodes during EAE. In contrast, meningeal lymphatics do not undergo lymphangiogenesis during EAE, suggesting heterogeneity in CNS lymphatics. We conclude that increased lymphangiogenesis near the cribriform plate can contribute to the management of neuroinflammation-induced fluid accumulation and immune surveillance. Lymphangiogenesis occurs in the context of systemic inflammation and development but has not been reported for the lymphatics that surround the CNS. Here the authors show that in the context of experimental autoimmune encephatlitis, lymphangiogenesis occurs at the cribriform plate, but not the meninges, and contributes to immune cell and antigen drainage.
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Affiliation(s)
- Martin Hsu
- Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Aditya Rayasam
- Neuroscience Training Program, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Julie A Kijak
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Yun Hwa Choi
- School of Pharmacy, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Jeffrey S Harding
- Samuel Lunenfeld Research Institute, Mount Sinai Hospital, Toronto, ON, M5T 3L9, Canada
| | - Sarah A Marcus
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - William J Karpus
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Matyas Sandor
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI, 53705, USA
| | - Zsuzsanna Fabry
- Department of Pathology and Laboratory Medicine, University of Wisconsin-Madison, Madison, WI, 53705, USA.
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27
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Semyachkina-Glushkovskaya O, Postnov D, Kurths J. Blood⁻Brain Barrier, Lymphatic Clearance, and Recovery: Ariadne's Thread in Labyrinths of Hypotheses. Int J Mol Sci 2018; 19:ijms19123818. [PMID: 30513598 PMCID: PMC6320935 DOI: 10.3390/ijms19123818] [Citation(s) in RCA: 19] [Impact Index Per Article: 3.2] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2018] [Revised: 11/21/2018] [Accepted: 11/23/2018] [Indexed: 12/25/2022] Open
Abstract
The peripheral lymphatic system plays a crucial role in the recovery mechanisms after many pathological changes, such as infection, trauma, vascular, or metabolic diseases. The lymphatic clearance of different tissues from waste products, viruses, bacteria, and toxic proteins significantly contributes to the correspondent recovery processes. However, understanding of the cerebral lymphatic functions is a challenging problem. The exploration of mechanisms of lymphatic communication with brain fluids as well as the role of the lymphatic system in brain drainage, clearance, and recovery is still in its infancy. Here we review novel concepts on the anatomy and physiology of the lymphatics in the brain, which warrant a substantial revision of our knowledge about the role of lymphatics in the rehabilitation of the brain functions after neural pathologies. We discuss a new vision on the connective bridge between the opening of a blood–brain barrier and activation of the meningeal lymphatic clearance. The ability to stimulate the lymph flow in the brain, is likely to play an important role in developing future innovative strategies in neurorehabilitation therapy.
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Affiliation(s)
| | - Dmitry Postnov
- Department of Optics and Biophotonics, Saratov State University, 83 Astrakhanskaya str., 410012 Saratov, Russia.
| | - Jürgen Kurths
- Department of Human and Animal Physiology, Saratov State University, Astrakhanskaya Str. 83, 410012 Saratov, Russia.
- Physics Department, Humboldt University, Newtonstrasse 15, 12489 Berlin, Germany.
- Potsdam Institute for Climate Impact Research, Telegrafenberg A31, 14473 Potsdam, Germany.
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28
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Hladky SB, Barrand MA. Elimination of substances from the brain parenchyma: efflux via perivascular pathways and via the blood-brain barrier. Fluids Barriers CNS 2018; 15:30. [PMID: 30340614 PMCID: PMC6194691 DOI: 10.1186/s12987-018-0113-6] [Citation(s) in RCA: 125] [Impact Index Per Article: 20.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/25/2018] [Accepted: 08/30/2018] [Indexed: 02/06/2023] Open
Abstract
This review considers efflux of substances from brain parenchyma quantified as values of clearances (CL, stated in µL g-1 min-1). Total clearance of a substance is the sum of clearance values for all available routes including perivascular pathways and the blood-brain barrier. Perivascular efflux contributes to the clearance of all water-soluble substances. Substances leaving via the perivascular routes may enter cerebrospinal fluid (CSF) or lymph. These routes are also involved in entry to the parenchyma from CSF. However, evidence demonstrating net fluid flow inwards along arteries and then outwards along veins (the glymphatic hypothesis) is still lacking. CLperivascular, that via perivascular routes, has been measured by following the fate of exogenously applied labelled tracer amounts of sucrose, inulin or serum albumin, which are not metabolized or eliminated across the blood-brain barrier. With these substances values of total CL ≅ 1 have been measured. Substances that are eliminated at least partly by other routes, i.e. across the blood-brain barrier, have higher total CL values. Substances crossing the blood-brain barrier may do so by passive, non-specific means with CLblood-brain barrier values ranging from < 0.01 for inulin to > 1000 for water and CO2. CLblood-brain barrier values for many small solutes are predictable from their oil/water partition and molecular weight. Transporters specific for glucose, lactate and many polar substrates facilitate efflux across the blood-brain barrier producing CLblood-brain barrier values > 50. The principal route for movement of Na+ and Cl- ions across the blood-brain barrier is probably paracellular through tight junctions between the brain endothelial cells producing CLblood-brain barrier values ~ 1. There are large fluxes of amino acids into and out of the brain across the blood-brain barrier but only small net fluxes have been observed suggesting substantial reuse of essential amino acids and α-ketoacids within the brain. Amyloid-β efflux, which is measurably faster than efflux of inulin, is primarily across the blood-brain barrier. Amyloid-β also leaves the brain parenchyma via perivascular efflux and this may be important as the route by which amyloid-β reaches arterial walls resulting in cerebral amyloid angiopathy.
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Affiliation(s)
- Stephen B. Hladky
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD UK
| | - Margery A. Barrand
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD UK
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29
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Bedussi B, Almasian M, de Vos J, VanBavel E, Bakker EN. Paravascular spaces at the brain surface: Low resistance pathways for cerebrospinal fluid flow. J Cereb Blood Flow Metab 2018; 38:719-726. [PMID: 29039724 PMCID: PMC5888857 DOI: 10.1177/0271678x17737984] [Citation(s) in RCA: 108] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Clearance of waste products from the brain is of vital importance. Recent publications suggest a potential clearance mechanism via paravascular channels around blood vessels. Arterial pulsations might provide the driving force for paravascular flow, but its flow pattern remains poorly characterized. In addition, the relationship between paravascular flow around leptomeningeal vessels and penetrating vessels is unclear. In this study, we determined blood flow and diameter pulsations through a thinned-skull cranial window. We observed that microspheres moved preferentially in the paravascular space of arteries rather than in the adjacent subarachnoid space or around veins. Paravascular flow was pulsatile, generated by the cardiac cycle, with net antegrade flow. Confocal imaging showed microspheres distributed along leptomeningeal arteries, while their presence along penetrating arteries was limited to few vessels. These data suggest that paravascular spaces around leptomeningeal arteries form low resistance pathways on the surface of the brain that facilitate cerebrospinal fluid flow.
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Affiliation(s)
- Beatrice Bedussi
- Department of Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, The Netherlands
| | - Mitra Almasian
- Department of Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, The Netherlands
| | - Judith de Vos
- Department of Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, The Netherlands
| | - Ed VanBavel
- Department of Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, The Netherlands
| | - Erik Ntp Bakker
- Department of Biomedical Engineering and Physics, Academic Medical Center, Amsterdam, The Netherlands
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30
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Abnormal cervical lymph nodes in multiple sclerosis: a preliminary ultrasound study. Radiol Med 2017; 123:202-208. [DOI: 10.1007/s11547-017-0829-4] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/14/2017] [Accepted: 10/27/2017] [Indexed: 02/01/2023]
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31
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de Leon MJ, Li Y, Okamura N, Tsui WH, Saint-Louis LA, Glodzik L, Osorio RS, Fortea J, Butler T, Pirraglia E, Fossati S, Kim HJ, Carare RO, Nedergaard M, Benveniste H, Rusinek H. Cerebrospinal Fluid Clearance in Alzheimer Disease Measured with Dynamic PET. J Nucl Med 2017; 58:1471-1476. [PMID: 28302766 DOI: 10.2967/jnumed.116.187211] [Citation(s) in RCA: 133] [Impact Index Per Article: 19.0] [Reference Citation Analysis] [Abstract] [Key Words] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/14/2016] [Accepted: 02/27/2017] [Indexed: 12/27/2022] Open
Abstract
Evidence supporting the hypothesis that reduced cerebrospinal fluid (CSF) clearance is involved in the pathophysiology of Alzheimer disease (AD) comes primarily from rodent models. However, unlike rodents, in which predominant extracranial CSF egress is via olfactory nerves traversing the cribriform plate, human CSF clearance pathways are not well characterized. Dynamic PET with 18F-THK5117, a tracer for tau pathology, was used to estimate the ventricular CSF time-activity as a biomarker for CSF clearance. We tested 3 hypotheses: extracranial CSF is detected at the superior turbinates; CSF clearance is reduced in AD; and CSF clearance is inversely associated with amyloid deposition. Methods: Fifteen subjects, 8 with AD and 7 normal control volunteers, were examined with 18F-THK5117. Ten subjects additionally underwent 11C-Pittsburgh compound B (11C-PiB) PET scanning, and 8 were 11C-PiB-positive. Ventricular time-activity curves of 18F-THK5117 were used to identify highly correlated time-activity curves from extracranial voxels. Results: For all subjects, the greatest density of CSF-positive extracranial voxels was in the nasal turbinates. Tracer concentration analyses validated the superior nasal turbinate CSF signal intensity. AD patients showed ventricular tracer clearance reduced by 23% and 66% fewer superior turbinate CSF egress sites. Ventricular CSF clearance was inversely associated with amyloid deposition. Conclusion: The human nasal turbinate is part of the CSF clearance system. Lateral ventricle and superior nasal turbinate CSF clearance abnormalities are found in AD. Ventricular CSF clearance reductions are associated with increased brain amyloid depositions. These data suggest that PET-measured CSF clearance is a biomarker of potential interest in AD and other neurodegenerative diseases.
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Affiliation(s)
- Mony J de Leon
- Department of Psychiatry, New York University School of Medicine, Center for Brain Health, New York, New York
| | - Yi Li
- Department of Psychiatry, New York University School of Medicine, Center for Brain Health, New York, New York
| | - Nobuyuki Okamura
- Department of Pharmacology, Tohoku University School of Medicine, Tohoku, Japan
| | - Wai H Tsui
- Department of Psychiatry, New York University School of Medicine, Center for Brain Health, New York, New York
| | | | - Lidia Glodzik
- Department of Psychiatry, New York University School of Medicine, Center for Brain Health, New York, New York.,Department of Radiology, New York University Center School of Medicine, New York, New York
| | - Ricardo S Osorio
- Department of Psychiatry, New York University School of Medicine, Center for Brain Health, New York, New York
| | - Juan Fortea
- Memory Unit, Department of Neurology, Hospital de la Santa Creu i Sant Pau, Biomedical Research Institute Sant Pau, Universitat Autònoma de Barcelona, Barcelona, Spain
| | - Tracy Butler
- Department of Psychiatry, New York University School of Medicine, Center for Brain Health, New York, New York
| | - Elizabeth Pirraglia
- Department of Psychiatry, New York University School of Medicine, Center for Brain Health, New York, New York
| | - Silvia Fossati
- Department of Psychiatry, New York University School of Medicine, Center for Brain Health, New York, New York.,Department of Neurology, New York University School of Medicine, New York, New York
| | - Hee-Jin Kim
- Department of Psychiatry, New York University School of Medicine, Center for Brain Health, New York, New York.,Department of Neurology, College of Medicine, Hanyang University, Seoul, Korea
| | - Roxana O Carare
- Faculty of Medicine, University of Southampton, Southampton, United Kingdom
| | - Maiken Nedergaard
- Center for Translational Neuromedicine, University of Rochester Medical Center, Rochester, New York.,Center for Basic and Translational Neuroscience, University of Copenhagen, Copenhagen, Denmark; and
| | - Helene Benveniste
- Department of Anesthesiology, Yale School of Medicine, New Haven, Connecticut
| | - Henry Rusinek
- Department of Radiology, New York University Center School of Medicine, New York, New York
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32
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Louveau A, Da Mesquita S, Kipnis J. Lymphatics in Neurological Disorders: A Neuro-Lympho-Vascular Component of Multiple Sclerosis and Alzheimer's Disease? Neuron 2016; 91:957-973. [PMID: 27608759 PMCID: PMC5019121 DOI: 10.1016/j.neuron.2016.08.027] [Citation(s) in RCA: 111] [Impact Index Per Article: 13.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/21/2022]
Abstract
Lymphatic vasculature drains interstitial fluids, which contain the tissue's waste products, and ensures immune surveillance of the tissues, allowing immune cell recirculation. Until recently, the CNS was considered to be devoid of a conventional lymphatic vasculature. The recent discovery in the meninges of a lymphatic network that drains the CNS calls into question classic models for the drainage of macromolecules and immune cells from the CNS. In the context of neurological disorders, the presence of a lymphatic system draining the CNS potentially offers a new player and a new avenue for therapy. In this review, we will attempt to integrate the known primary functions of the tissue lymphatic vasculature that exists in peripheral organs with the proposed function of meningeal lymphatic vessels in neurological disorders, specifically multiple sclerosis and Alzheimer's disease. We propose that these (and potentially other) neurological afflictions can be viewed as diseases with a neuro-lympho-vascular component and should be therapeutically targeted as such.
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Affiliation(s)
- Antoine Louveau
- Center for Brain Immunology and Glia, Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - Sandro Da Mesquita
- Center for Brain Immunology and Glia, Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - Jonathan Kipnis
- Center for Brain Immunology and Glia, Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA.
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33
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Dhuria SV, Fine JM, Bingham D, Svitak AL, Burns RB, Baillargeon AM, Panter SS, Kazi AN, Frey WH, Hanson LR. Food consumption and activity levels increase in rats following intranasal Hypocretin-1. Neurosci Lett 2016; 627:155-9. [DOI: 10.1016/j.neulet.2016.05.053] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/24/2016] [Revised: 05/20/2016] [Accepted: 05/25/2016] [Indexed: 01/28/2023]
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Lymphatic Clearance of the Brain: Perivascular, Paravascular and Significance for Neurodegenerative Diseases. Cell Mol Neurobiol 2016; 36:181-94. [PMID: 26993512 PMCID: PMC4844641 DOI: 10.1007/s10571-015-0273-8] [Citation(s) in RCA: 255] [Impact Index Per Article: 31.9] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/29/2015] [Accepted: 09/18/2015] [Indexed: 01/04/2023]
Abstract
The lymphatic clearance pathways of the brain are different compared to the other organs of the body and have been the subject of heated debates. Drainage of brain extracellular fluids, particularly interstitial fluid (ISF) and cerebrospinal fluid (CSF), is not only important for volume regulation, but also for removal of waste products such as amyloid beta (Aβ). CSF plays a special role in clinical medicine, as it is available for analysis of biomarkers for Alzheimer's disease. Despite the lack of a complete anatomical and physiological picture of the communications between the subarachnoid space (SAS) and the brain parenchyma, it is often assumed that Aβ is cleared from the cerebral ISF into the CSF. Recent work suggests that clearance of the brain mainly occurs during sleep, with a specific role for peri- and para-vascular spaces as drainage pathways from the brain parenchyma. However, the direction of flow, the anatomical structures involved and the driving forces remain elusive, with partially conflicting data in literature. The presence of Aβ in the glia limitans in Alzheimer's disease suggests a direct communication of ISF with CSF. Nonetheless, there is also the well-described pathology of cerebral amyloid angiopathy associated with the failure of perivascular drainage of Aβ. Herein, we review the role of the vasculature and the impact of vascular pathology on the peri- and para-vascular clearance pathways of the brain. The different views on the possible routes for ISF drainage of the brain are discussed in the context of pathological significance.
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35
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Wolf DA, Hesterman JY, Sullivan JM, Orcutt KD, Silva MD, Lobo M, Wellman T, Hoppin J, Verma A. Dynamic dual-isotope molecular imaging elucidates principles for optimizing intrathecal drug delivery. JCI Insight 2016; 1:e85311. [PMID: 27699254 DOI: 10.1172/jci.insight.85311] [Citation(s) in RCA: 25] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
The intrathecal (IT) dosing route offers a seemingly obvious solution for delivering drugs directly to the central nervous system. However, gaps in understanding drug molecule behavior within the anatomically and kinetically unique environment of the mammalian IT space have impeded the establishment of pharmacokinetic principles for optimizing regional drug exposure along the neuraxis. Here, we have utilized high-resolution single-photon emission tomography with X-ray computed tomography to study the behavior of multiple molecular imaging tracers following an IT bolus injection, with supporting histology, autoradiography, block-face tomography, and MRI. Using simultaneous dual-isotope imaging, we demonstrate that the regional CNS tissue exposure of molecules with varying chemical properties is affected by IT space anatomy, cerebrospinal fluid (CSF) dynamics, CSF clearance routes, and the location and volume of the injected bolus. These imaging approaches can be used across species to optimize the safety and efficacy of IT drug therapy for neurological disorders.
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Affiliation(s)
- Daniel A Wolf
- Experimental Medicine, Biogen Inc., Cambridge, Massachusetts, USA
| | | | | | | | | | | | | | | | - Ajay Verma
- Experimental Medicine, Biogen Inc., Cambridge, Massachusetts, USA
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Louveau A, Harris TH, Kipnis J. Revisiting the Mechanisms of CNS Immune Privilege. Trends Immunol 2015; 36:569-577. [PMID: 26431936 PMCID: PMC4593064 DOI: 10.1016/j.it.2015.08.006] [Citation(s) in RCA: 441] [Impact Index Per Article: 49.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/26/2015] [Revised: 08/13/2015] [Accepted: 08/13/2015] [Indexed: 12/25/2022]
Abstract
Whereas the study of the interactions between the immune system and the central nervous system (CNS) has often focused on pathological conditions, the importance of neuroimmune communication in CNS homeostasis and function has become clear over that last two decades. Here we discuss the progression of our understanding of the interaction between the peripheral immune system and the CNS. We examine the notion of immune privilege of the CNS in light of both earlier findings and recent studies revealing a functional meningeal lymphatic system that drains cerebrospinal fluid (CSF) to the deep cervical lymph nodes, and consider the implications of a revised perspective on the immune privilege of the CNS on the etiology and pathology of different neurological disorders.
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Affiliation(s)
- Antoine Louveau
- Center for Brain Immunology and Glia, Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - Tajie H Harris
- Center for Brain Immunology and Glia, Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA
| | - Jonathan Kipnis
- Center for Brain Immunology and Glia, Department of Neuroscience, School of Medicine, University of Virginia, Charlottesville, VA 22908, USA.
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Dienel GA, Cruz NF. Contributions of glycogen to astrocytic energetics during brain activation. Metab Brain Dis 2015; 30:281-98. [PMID: 24515302 PMCID: PMC4130810 DOI: 10.1007/s11011-014-9493-8] [Citation(s) in RCA: 70] [Impact Index Per Article: 7.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/29/2013] [Accepted: 01/21/2014] [Indexed: 12/11/2022]
Abstract
Glycogen is the major store of glucose in brain and is mainly in astrocytes. Brain glycogen levels in unstimulated, carefully-handled rats are 10-12 μmol/g, and assuming that astrocytes account for half the brain mass, astrocytic glycogen content is twice as high. Glycogen turnover is slow under basal conditions, but it is mobilized during activation. There is no net increase in incorporation of label from glucose during activation, whereas label release from pre-labeled glycogen exceeds net glycogen consumption, which increases during stronger stimuli. Because glycogen level is restored by non-oxidative metabolism, astrocytes can influence the global ratio of oxygen to glucose utilization. Compensatory increases in utilization of blood glucose during inhibition of glycogen phosphorylase are large and approximate glycogenolysis rates during sensory stimulation. In contrast, glycogenolysis rates during hypoglycemia are low due to continued glucose delivery and oxidation of endogenous substrates; rates that preserve neuronal function in the absence of glucose are also low, probably due to metabolite oxidation. Modeling studies predict that glycogenolysis maintains a high level of glucose-6-phosphate in astrocytes to maintain feedback inhibition of hexokinase, thereby diverting glucose for use by neurons. The fate of glycogen carbon in vivo is not known, but lactate efflux from brain best accounts for the major metabolic characteristics during activation of living brain. Substantial shuttling coupled with oxidation of glycogen-derived lactate is inconsistent with available evidence. Glycogen has important roles in astrocytic energetics, including glucose sparing, control of extracellular K(+) level, oxidative stress management, and memory consolidation; it is a multi-functional compound.
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Affiliation(s)
- Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, Slot 500, 4301 W. Markham St., Little Rock, AR, 72205, USA,
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Hladky SB, Barrand MA. Mechanisms of fluid movement into, through and out of the brain: evaluation of the evidence. Fluids Barriers CNS 2014; 11:26. [PMID: 25678956 PMCID: PMC4326185 DOI: 10.1186/2045-8118-11-26] [Citation(s) in RCA: 388] [Impact Index Per Article: 38.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2014] [Accepted: 11/21/2014] [Indexed: 01/08/2023] Open
Abstract
Interstitial fluid (ISF) surrounds the parenchymal cells of the brain and spinal cord while cerebrospinal fluid (CSF) fills the larger spaces within and around the CNS. Regulation of the composition and volume of these fluids is important for effective functioning of brain cells and is achieved by barriers that prevent free exchange between CNS and blood and by mechanisms that secrete fluid of controlled composition into the brain and distribute and reabsorb it. Structures associated with this regular fluid turnover include the choroid plexuses, brain capillaries comprising the blood-brain barrier, arachnoid villi and perineural spaces penetrating the cribriform plate. ISF flow, estimated from rates of removal of markers from the brain, has been thought to reflect rates of fluid secretion across the blood-brain barrier, although this has been questioned because measurements were made under barbiturate anaesthesia possibly affecting secretion and flow and because CSF influx to the parenchyma via perivascular routes may deliver fluid independently of blood-brain barrier secretion. Fluid secretion at the blood-brain barrier is provided by specific transporters that generate solute fluxes so creating osmotic gradients that force water to follow. Any flow due to hydrostatic pressures driving water across the barrier soon ceases unless accompanied by solute transport because water movements modify solute concentrations. CSF is thought to be derived primarily from secretion by the choroid plexuses. Flow rates measured using phase contrast magnetic resonance imaging reveal CSF movements to be more rapid and variable than previously supposed, even implying that under some circumstances net flow through the cerebral aqueduct may be reversed with net flow into the third and lateral ventricles. Such reversed flow requires there to be alternative sites for both generation and removal of CSF. Fluorescent tracer analysis has shown that fluid flow can occur from CSF into parenchyma along periarterial spaces. Whether this represents net fluid flow and whether there is subsequent flow through the interstitium and net flow out of the cortex via perivenous routes, described as glymphatic circulation, remains to be established. Modern techniques have revealed complex fluid movements within the brain. This review provides a critical evaluation of the data.
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Affiliation(s)
- Stephen B Hladky
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD UK
| | - Margery A Barrand
- Department of Pharmacology, University of Cambridge, Cambridge, CB2 1PD UK
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Lactate shuttling and lactate use as fuel after traumatic brain injury: metabolic considerations. J Cereb Blood Flow Metab 2014; 34:1736-48. [PMID: 25204393 PMCID: PMC4269761 DOI: 10.1038/jcbfm.2014.153] [Citation(s) in RCA: 58] [Impact Index Per Article: 5.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 06/17/2014] [Accepted: 07/31/2014] [Indexed: 11/08/2022]
Abstract
Lactate is proposed to be generated by astrocytes during glutamatergic neurotransmission and shuttled to neurons as 'preferred' oxidative fuel. However, a large body of evidence demonstrates that metabolic changes during activation of living brain disprove essential components of the astrocyte-neuron lactate shuttle model. For example, some glutamate is oxidized to generate ATP after its uptake into astrocytes and neuronal glucose phosphorylation rises during activation and provides pyruvate for oxidation. Extension of the notion that lactate is a preferential fuel into the traumatic brain injury (TBI) field has important clinical implications, and the concept must, therefore, be carefully evaluated before implementation into patient care. Microdialysis studies in TBI patients demonstrate that lactate and pyruvate levels and lactate/pyruvate ratios, along with other data, have important diagnostic value to distinguish between ischemia and mitochondrial dysfunction. Results show that lactate release from human brain to blood predominates over its uptake after TBI, and strong evidence for lactate metabolism is lacking; mitochondrial dysfunction may inhibit lactate oxidation. Claims that exogenous lactate infusion is energetically beneficial for TBI patients are not based on metabolic assays and data are incorrectly interpreted.
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Murtha LA, Yang Q, Parsons MW, Levi CR, Beard DJ, Spratt NJ, McLeod DD. Cerebrospinal fluid is drained primarily via the spinal canal and olfactory route in young and aged spontaneously hypertensive rats. Fluids Barriers CNS 2014; 11:12. [PMID: 24932405 PMCID: PMC4057524 DOI: 10.1186/2045-8118-11-12] [Citation(s) in RCA: 80] [Impact Index Per Article: 8.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/04/2014] [Accepted: 05/27/2014] [Indexed: 11/10/2022] Open
Abstract
BACKGROUND Many aspects of CSF dynamics are poorly understood due to the difficulties involved in quantification and visualization. In particular, there is debate surrounding the route of CSF drainage. Our aim was to quantify CSF flow, volume, and drainage route dynamics in vivo in young and aged spontaneously hypertensive rats (SHR) using a novel contrast-enhanced computed tomography (CT) method. METHODS ICP was recorded in young (2-5 months) and aged (16 months) SHR. Contrast was administered into the lateral ventricles bilaterally and sequential CT imaging was used to visualize the entire intracranial CSF system and CSF drainage routes. A customized contrast decay software module was used to quantify CSF flow at multiple locations. RESULTS ICP was significantly higher in aged rats than in young rats (11.52 ± 2.36 mmHg, versus 7.04 ± 2.89 mmHg, p = 0.03). Contrast was observed throughout the entire intracranial CSF system and was seen to enter the spinal canal and cross the cribriform plate into the olfactory mucosa within 9.1 ± 6.1 and 22.2 ± 7.1 minutes, respectively. No contrast was observed adjacent to the sagittal sinus. There were no significant differences between young and aged rats in either contrast distribution times or CSF flow rates. Mean flow rates (combined young and aged) were 3.0 ± 1.5 μL/min at the cerebral aqueduct; 3.5 ± 1.4 μL/min at the 3rd ventricle; and 2.8 ± 0.9 μL/min at the 4th ventricle. Intracranial CSF volumes (and as percentage total brain volume) were 204 ± 97 μL (8.8 ± 4.3%) in the young and 275 ± 35 μL (10.8 ± 1.9%) in the aged animals (NS). CONCLUSIONS We have demonstrated a contrast-enhanced CT technique for measuring and visualising CSF dynamics in vivo. These results indicate substantial drainage of CSF via spinal and olfactory routes, but there was little evidence of drainage via sagittal sinus arachnoid granulations in either young or aged animals. The data suggests that spinal and olfactory routes are the primary routes of CSF drainage and that sagittal sinus arachnoid granulations play a minor role, even in aged rats with higher ICP.
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Affiliation(s)
- Lucy A Murtha
- University of Newcastle and Hunter Medical Research Institute, University of Newcastle: School of Biomedical Sciences & Pharmacy, Medical Sciences Building, Callaghan, NSW 2308, Australia
| | - Qing Yang
- Apollo Medical Imaging Technology Pty Ltd, Suite 611, 365 Little Collins Street, Melbourne, Vic 3000, Australia
| | - Mark W Parsons
- Hunter New England Local Health District: Department of Neurology, John Hunter Hospital, Locked Bag 1, Hunter Region M.C, NSW 2310, Australia
| | - Christopher R Levi
- Hunter New England Local Health District: Department of Neurology, John Hunter Hospital, Locked Bag 1, Hunter Region M.C, NSW 2310, Australia
| | - Daniel J Beard
- University of Newcastle and Hunter Medical Research Institute, University of Newcastle: School of Biomedical Sciences & Pharmacy, Medical Sciences Building, Callaghan, NSW 2308, Australia
| | - Neil J Spratt
- University of Newcastle and Hunter Medical Research Institute, University of Newcastle: School of Biomedical Sciences & Pharmacy, Medical Sciences Building, Callaghan, NSW 2308, Australia
- Hunter New England Local Health District: Department of Neurology, John Hunter Hospital, Locked Bag 1, Hunter Region M.C, NSW 2310, Australia
| | - Damian D McLeod
- University of Newcastle and Hunter Medical Research Institute, University of Newcastle: School of Biomedical Sciences & Pharmacy, Medical Sciences Building, Callaghan, NSW 2308, Australia
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Veening JG, Olivier B. Intranasal administration of oxytocin: behavioral and clinical effects, a review. Neurosci Biobehav Rev 2013; 37:1445-65. [PMID: 23648680 PMCID: PMC7112651 DOI: 10.1016/j.neubiorev.2013.04.012] [Citation(s) in RCA: 133] [Impact Index Per Article: 12.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/01/2012] [Revised: 04/22/2013] [Accepted: 04/24/2013] [Indexed: 12/11/2022]
Abstract
The mechanisms behind the effects of IN-applied substances need more attention. The mechanisms involved in the brain-distribution of IN-OT are completely unexplored. The possibly cascading effects of IN-OT on the intrinsic OT-system require serious investigation. IN-OT induces clear and specific changes in neural activation. IN-OT is a promising approach to treat certain clinical symptoms.
The intranasal (IN-) administration of substances is attracting attention from scientists as well as pharmaceutical companies. The effects are surprisingly fast and specific. The present review explores our current knowledge about the routes of access to the cranial cavity. ‘Direct-access-pathways’ from the nasal cavity have been described but many additional experiments are needed to answer a variety of open questions regarding anatomy and physiology. Among the IN-applied substances oxytocin (OT) has an extensive history. Originally applied in women for its physiological effects related to lactation and parturition, over the last decade most studies focused on their behavioral ‘prosocial’ effects: from social relations and ‘trust’ to treatment of ‘autism’. Only very recently in a microdialysis study in rats and mice, the ‘direct-nose-brain-pathways’ of IN-OT have been investigated directly, implying that we are strongly dependent on results obtained from other IN-applied substances. Especially the possibility that IN-OT activates the ‘intrinsic’ OT-system in the hypothalamus as well needs further clarification. We conclude that IN-OT administration may be a promising approach to influence human communication but that the existing lack of information about the neural and physiological mechanisms involved is a serious problem for the proper understanding and interpretation of the observed effects.
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Affiliation(s)
- Jan G Veening
- Division of Pharmacology, Utrecht Institute for Pharmaceutical Sciences, Utrecht University, P.O. Box 80082, 3508 TB, Utrecht, The Netherlands; Department of Anatomy (109), Radboud University of Medical Sciences, P.O. Box 9101, 6500 HB, Nijmegen, The Netherlands.
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Chikly B, Quaghebeur J. Reassessing cerebrospinal fluid (CSF) hydrodynamics: a literature review presenting a novel hypothesis for CSF physiology. J Bodyw Mov Ther 2013; 17:344-54. [PMID: 23768280 DOI: 10.1016/j.jbmt.2013.02.002] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/03/2012] [Revised: 12/27/2012] [Accepted: 01/30/2013] [Indexed: 10/27/2022]
Abstract
The traditional model of cerebrospinal fluid (CSF) hydrodynamics is being increasingly challenged in view of recent scientific evidences. The established model presumes that CSF is primarily produced in the choroid plexuses (CP), then flows from the ventricles to the subarachnoid spaces, and is mainly reabsorbed into arachnoid villi (AV). This model is seemingly based on faulty research and misinterpretations. This literature review presents numerous evidence for a new hypothesis of CSF physiology, namely, CSF is produced and reabsorbed throughout the entire CSF-Interstitial fluid (IF) functional unit. IF and CSF are mainly formed and reabsorbed across the walls of CNS blood capillaries. CP, AV and lymphatics become minor sites for CSF hydrodynamics. The lymphatics may play a more significant role in CSF absorption when CSF-IF pressure increases. The consequences of this complete reformulation of CSF hydrodynamics may influence applications in research, publications, including osteopathic manual treatments.
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Cruz NF, Ball KK, Froehner SC, Adams ME, Dienel GA. Regional registration of [6-(14)C]glucose metabolism during brain activation of α-syntrophin knockout mice. J Neurochem 2013; 125:247-59. [PMID: 23346911 DOI: 10.1111/jnc.12166] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 01/02/2013] [Accepted: 01/20/2013] [Indexed: 12/16/2022]
Abstract
α-Syntrophin is a component of the dystrophin scaffold-protein complex that serves as an adaptor for recruitment of key proteins to the cytoplasmic side of plasma membranes. α-Syntrophin knockout (KO) causes loss of the polarized localization of aquaporin4 (AQP4) at astrocytic endfeet and interferes with water and K(+) homeostasis. During brain activation, release of ions and metabolites from endfeet is anticipated to increase perivascular fluid osmolarity, AQP4-mediated osmotic water flow from endfeet, and metabolite washout from brain. This study tests the hypothesis that reduced levels of endfoot AQP4 increase retention of [(14)C]metabolites during sensory stimulation. Conscious KO and wild-type mice were pulse-labeled with [6-(14)C] glucose during unilateral acoustic stimulation or bilateral acoustic plus whisker stimulation, and label retention was assayed by computer-assisted brain imaging or analysis of [(14)C]metabolites in extracts, respectively. High-resolution autoradiographic assays detected a 17% side-to-side difference (p < 0.05) in inferior colliculus of KO mice, not wild-type mice. However, there were no labeling differences between KO and wild-type mice for five major HPLC fractions from four dissected regions, presumably because of insufficient anatomical resolution. The results suggest a role for AQP4-mediated water flow in support of washout of metabolites, and underscore the need for greater understanding of astrocytic water and metabolite fluxes.
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Affiliation(s)
- Nancy F Cruz
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Kelly K Ball
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
| | - Stanley C Froehner
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington, USA
| | - Marvin E Adams
- Department of Physiology and Biophysics, University of Washington, Seattle, Washington, USA
| | - Gerald A Dienel
- Department of Neurology, University of Arkansas for Medical Sciences, Little Rock, Arkansas, USA
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D’Agostino PM, Gottfried-Blackmore A, Anandasabapathy N, Bulloch K. Brain dendritic cells: biology and pathology. Acta Neuropathol 2012; 124:599-614. [PMID: 22825593 PMCID: PMC3700359 DOI: 10.1007/s00401-012-1018-0] [Citation(s) in RCA: 124] [Impact Index Per Article: 10.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/21/2012] [Revised: 07/12/2012] [Accepted: 07/12/2012] [Indexed: 12/19/2022]
Abstract
Dendritic cells (DC) are the professional antigen-presenting cells of the immune system. In their quiescent and mature form, the presentation of self-antigens by DC leads to tolerance; whereas, antigen presentation by mature DC, after stimulation by pathogen-associated molecular patterns, leads to the onset of antigen-specific immunity. DC have been found in many of the major organs in mammals (e.g. skin, heart, lungs, intestines and spleen); while the brain has long been considered devoid of DC in the absence of neuroinflammation. Consequently, microglia, the resident immune cell of the brain, have been charged with many functional attributes commonly ascribed to DC. Recent evidence has challenged the notion that DC are either absent or minimal players in brain immune surveillance. This review will discuss the recent literature examining DC involvement within both the young and aged steady-state brain. We will also examine DC contributions during various forms of neuroinflammation resulting from neurodegenerative autoimmune disease, injury, and CNS infections. This review also touches upon DC trafficking between the central nervous system and peripheral immune compartments during viral infections, the new molecular technologies that could be employed to enhance our current understanding of brain DC ontogeny, and some potential therapeutic uses of DC within the CNS.
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Affiliation(s)
- Paul M. D’Agostino
- The Laboratories of Neuroendocrinology, The Rockefeller University, New York, NY 10065, USA
| | | | - Niroshana Anandasabapathy
- The Laboratories of Cellular Physiology and Immunology, The Rockefeller University, New York, NY 10065, USA
| | - Karen Bulloch
- The Laboratories of Neuroendocrinology, The Rockefeller University, New York, NY 10065, USA. The Laboratories of Cellular Physiology and Immunology, The Rockefeller University, New York, NY 10065, USA. The Laboratories of Molecular Immunology, The Rockefeller University, New York, NY 10065, USA. Neuroimmunology and Inflammation Program, The Rockefeller University, 1230 York Avenue, Box 165, New York, NY 10065, USA
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Swiderski RE, Agassandian K, Ross JL, Bugge K, Cassell MD, Yeaman C. Structural defects in cilia of the choroid plexus, subfornical organ and ventricular ependyma are associated with ventriculomegaly. Fluids Barriers CNS 2012; 9:22. [PMID: 23046663 PMCID: PMC3527152 DOI: 10.1186/2045-8118-9-22] [Citation(s) in RCA: 28] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2012] [Accepted: 10/03/2012] [Indexed: 12/02/2022] Open
Abstract
Background Hydrocephalus is a heterogeneous disorder with multiple etiologies that are not yet fully understood. Animal models have implicated dysfunctional cilia of the ependyma and choroid plexus in the development of the disorder. In this report, we sought to determine the origin of the ventriculomegaly in four Bardet Biedl syndrome (BBS) mutant mouse strains as models of a ciliopathy. Methods Evans Blue dye was injected into the lateral ventricle of wild- type and BBS mutant mice to determine whether obstruction of intra- or extra-ventricular CSF flow contributed to ventriculomegaly. Transmission electron microscopy (TEM) was used to examine the ultrastructure of the choroid plexus, subfornical organ (SFO), subcommisural organ (SCO), and ventricular ependyma to evaluate their ultrastructure and the morphology of their primary and motile cilia. Results and discussion No obstruction of intra- or extra-ventricular CSF flow was observed, implying a communicating form of hydrocephalus in BBS mutant mice. TEM analyses of the mutants showed no evidence of choroidal papillomas or breakdown of the blood:CSF barrier. In contrast, structural defects were observed in a subpopulation of cilia lining the choroid plexus, SFO, and ventricular ependyma. These included disruptions of the microtubular structure of the axoneme and the presence of electron-dense vesicular-like material along the ciliary shaft and at the tips of cilia. Conclusions Abnormalities in cilia structure and function have the potential to influence ciliary intraflagellar transport (IFT), cilia maintenance, protein trafficking, and regulation of CSF production. Ciliary structural defects are the only consistent pathological features associated with CSF-related structures in BBS mutant mice. These defects are observed from an early age, and may contribute to the underlying pathophysiology of ventriculomegaly.
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Affiliation(s)
- Ruth E Swiderski
- Department of Anatomy and Cell Biology, The University of Iowa, Iowa City, 52242, IA, USA.
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Increased intracranial pressure after diffuse traumatic brain injury exacerbates neuronal somatic membrane poration but not axonal injury: evidence for primary intracranial pressure-induced neuronal perturbation. J Cereb Blood Flow Metab 2012; 32:1919-32. [PMID: 22781336 PMCID: PMC3463883 DOI: 10.1038/jcbfm.2012.95] [Citation(s) in RCA: 39] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Increased intracranial pressure (ICP) associated with traumatic brain injury (TBI) is linked to increased morbidity. Although our understanding of the pathobiology of TBI has expanded, questions remain regarding the specific neuronal somatic and axonal damaging consequences of elevated ICP, independent of its impact on cerebral perfusion pressure (CPP). To investigate this, Fischer rats were subjected to moderate TBI. Measurements of ICP revealed two distinct responses to injury. One population exhibited transient increases in ICP that returned to baseline levels acutely, while the other displayed persistent ICP elevation (>20 mm Hg). Utilizing these populations, the effect of elevated ICP on neuronal pathology associated with diffuse TBI was analyzed at 6 hours after TBI. No difference in axonal injury was observed, however, rats exhibiting persistently elevated ICP postinjury revealed a doubling of neurons with chronic membrane poration compared with rats exhibiting only transient increases in ICP. Elevated postinjury ICP was not associated with a concurrent increase in DNA damage; however, traditional histological assessments did reveal increased neuronal damage, potentially associated with redistribution of cathepsin-B from the lysosomal compartment into the cytosol. These findings indicate that persistently increased ICP, without deleterious alteration of CPP, exacerbates neuronal plasmalemmal perturbation that could precipitate persistent neuronal impairment and ultimate neuronal death.
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Nasal-to-CNS drug delivery: where are we now and where are we heading? An industrial perspective. Ther Deliv 2012; 3:195-208. [PMID: 22834197 DOI: 10.4155/tde.11.149] [Citation(s) in RCA: 35] [Impact Index Per Article: 2.9] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Abstract
Delivery of drug therapeutics across the blood-brain barrier is a challenging task for pharmaceutical scientists. Nasal-to-CNS drug delivery has shown promising results in preclinical efficacy models and investigatory human clinical trials. The further development of this technology with respect to the establishment of valid, predictable preclinical species models, translatable pharmacokinetic-pharmacodynamic relationships and definition of toxicology impact will help attract additional pharmaceutical investment in this drug-delivery approach. Further discoveries in nasal nanotechnology, targeted delivery devices and diagnostic olfactory imaging will serve to fuel the advancements in this area of drug delivery.
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Olfactory nerve--a novel invasion route of Neisseria meningitidis to reach the meninges. PLoS One 2010; 5:e14034. [PMID: 21124975 PMCID: PMC2987801 DOI: 10.1371/journal.pone.0014034] [Citation(s) in RCA: 52] [Impact Index Per Article: 3.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/18/2010] [Accepted: 10/29/2010] [Indexed: 11/19/2022] Open
Abstract
Neisseria meningitidis is a human-specific pathogen with capacity to cause septic shock and meningitis. It has been hypothesized that invasion of the central nervous system (CNS) is a complication of a bacteremic condition. In this study, we aimed to characterize the invasion route of N. meningitidis to the CNS. Using an intranasally challenged mouse disease model, we found that twenty percent of the mice developed lethal meningitis even though no bacteria could be detected in blood. Upon bacterial infection, epithelial lesions and redistribution of intracellular junction protein N-cadherin were observed at the nasal epithelial mucosa, especially at the olfactory epithelium, which is functionally and anatomically connected to the CNS. Bacteria were detected in the submucosa of the olfactory epithelium, along olfactory nerves in the cribriform plate, at the olfactory bulb and subsequently at the meninges and subarachnoid space. Furthermore, our data suggest that a threshold level of bacteremia is required for the development of meningococcal sepsis. Taken together, N. meningitidis is able to pass directly from nasopharynx to meninges through the olfactory nerve system. This study enhances our understanding how N. meningitidis invades the meninges. The nasal olfactory nerve system may be a novel target for disease prevention that can improve outcome and survival.
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Nagra G, Wagshul ME, Rashid S, Li J, McAllister JP, Johnston M. Elevated CSF outflow resistance associated with impaired lymphatic CSF absorption in a rat model of kaolin-induced communicating hydrocephalus. Cerebrospinal Fluid Res 2010; 7:4. [PMID: 20181144 PMCID: PMC2831828 DOI: 10.1186/1743-8454-7-4] [Citation(s) in RCA: 20] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/04/2009] [Accepted: 02/10/2010] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND We recently reported a lymphatic cerebrospinal fluid (CSF) absorption deficit in a kaolin model of communicating hydrocephalus in rats with ventricular expansion correlating negatively with the magnitude of the impediment to lymphatic function. However, it is possible that CSF drainage was not significantly altered if absorption at other sites compensated for the lymphatic defect. The purpose of this study was to investigate the impact of the lymphatic absorption deficit on global CSF absorption (CSF outflow resistance). METHODS Kaolin was injected into the basal cisterns of Sprague Dawley rats. The development of hydrocephalus was assessed using magnetic resonance imaging (MRI). In one group of animals at about 3 weeks after injection, the movement of intraventricularly injected iodinated human serum albumin (125I-HSA) into the olfactory turbinates provided an estimate of CSF transport through the cribriform plate into nasal lymphatics (n = 18). Control animals received saline in place of kaolin (n = 10). In a second group at about 3.5 weeks after kaolin injection, intraventricular pressure was measured continuously during infusion of saline into the spinal subarachnoid space at various flow rates (n = 9). CSF outflow resistance was calculated as the slope of the steady-state pressure versus flow rate. Control animals for this group either received no injections (intact: n = 11) or received saline in place of kaolin (n = 8). RESULTS Compared to saline injected controls, lateral ventricular volume in the kaolin group was significantly greater (0.087 +/- 0.013 ml, n = 27 versus 0.015 +/- 0.001 ml, n = 17) and lymphatic function was significantly less (2.14 +/- 0.72% injected/g, n = 18 versus 6.38 +/- 0.60% injected/g, n = 10). Additionally, the CSF outflow resistance was significantly greater in the kaolin group (0.46 +/- 0.04 cm H2O microL(-1) min, n = 9) than in saline injected (0.28 +/- 0.03 cm H2O microL(-1) min, n = 8) or intact animals (0.18 +/- 0.03 cm H2O microL(-1) min, n = 11). There was a significant positive correlation between CSF outflow resistance and ventricular volume. CONCLUSIONS The data suggest that the impediment to lymphatic CSF absorption in a kaolin-induced model of communicating hydrocephalus has a significant impact on global CSF absorption. A lymphatic CSF absorption deficit would appear to play some role (either direct or indirect) in the pathogenesis of ventriculomegaly.
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Affiliation(s)
- Gurjit Nagra
- Brain Sciences Program, Department of Laboratory Medicine and Pathobiology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
| | - Mark E Wagshul
- Department of Radiology, Stony Brook University, Stony Brook, NY, USA
- Gruss Magnetic Resonance Research Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Shams Rashid
- Department of Radiology, Stony Brook University, Stony Brook, NY, USA
- Gruss Magnetic Resonance Research Center, Albert Einstein College of Medicine, Bronx, NY, USA
| | - Jie Li
- Department of Neurological Surgery, Wayne State University School of Medicine, University Health Center, St Antoine Detroit, MI, USA
| | - J Pat McAllister
- Department of Neurosurgery, Division of Pediatric Neurosurgery, University of Utah School of Medicine, Salt Lake City, UT, USA
| | - Miles Johnston
- Brain Sciences Program, Department of Laboratory Medicine and Pathobiology, Sunnybrook Health Sciences Centre, University of Toronto, Toronto, Ontario, Canada
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Veening JG, Barendregt HP. The regulation of brain states by neuroactive substances distributed via the cerebrospinal fluid; a review. Cerebrospinal Fluid Res 2010; 7:1. [PMID: 20157443 PMCID: PMC2821375 DOI: 10.1186/1743-8454-7-1] [Citation(s) in RCA: 97] [Impact Index Per Article: 6.9] [Reference Citation Analysis] [Abstract] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/21/2009] [Accepted: 01/06/2010] [Indexed: 01/04/2023] Open
Abstract
The cerebrospinal fluid (CSF) system provides nutrients to and removes waste products from the brain. Recent findings suggest, however, that in addition, the CSF contains message molecules in the form of actively released neuroactive substances. The concentrations of these vary between locations, suggesting they are important for the changes in brain activity that underlie different brain states, and induce different sensory input and behavioral output relationships.The cranial CSF displays a rapid caudally-directed ventricular flow followed by a slower rostrally-directed subarachnoid flow (mainly towards the cribriform plate and from there into the nasal lymphatics). Thus, many brain areas are exposed to and can be influenced by substances contained in the CSF. In this review we discuss the production and flow of the CSF, including the mechanisms involved in the regulation of its composition. In addition, the available evidence for the release of neuropeptides and other neuroactive substances into the CSF is reviewed, with particular attention to the selective effects of these on distant downstream receptive brain areas. As a conclusion we suggest that (1) the flowing CSF is involved in more than just nutrient and waste control, but is also used as a broadcasting system consisting of coordinated messages to a variety of nearby and distant brain areas; (2) this special form of volume transmission underlies changes in behavioral states.
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Affiliation(s)
- Jan G Veening
- Department of Anatomy, (109) UMC St Radboud, Nijmegen, the Netherlands.
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